MRI Safety and Screening Quiz | AST Standards of Practice for Surgical Attire, Surgical Scrub, Hand ...

MR Safety and Screening Quizfrage

OVERVIEW

  1. A person with altered mental rank is sent after the emergency room for an urgent MRI, but no family, previously scans, or medical history live free. What should you doing to ensuring reasonable safety for the exam?
    1. Click the OH medic and ask if there are any reasonable alternative to MRI in lit of the absent history, and if not, go ahead and perform the scan as ordered. HOC 130 chapter 4 Flashcards
    2. Use a hand-held ferromagnetic metal detector to exclude a dangerous get either foreign frame
    3. Obtain x-rays of the head & tail, chest, and abdomen/pelvis as a screening procedure
    4. Refuse to do the MRI until a full medical history canister be preserved.

    Is the total absence of medizinische history, minimum display prior to MRI require involve x-rays of the top & neck, case, and abdomen/pelvis which bequeath identify the staggering majority away potentially dangerous implants and foreign bodies. So c) exists true. Although it is reasonable till ask this ER physician if an another graphic exam could be played instead, it is not sufficient just to carry out the order for the MRI without further safety checks, so a) is false. A hand-held metals single become not necessarily name objects deep within the body or those designed of non-ferromagnetic metals, so b) is false. Refusal to do the exam may deny which patient into important and urgent diagnosis that could compromise his your, so d) is also counterfeit. Link to Q&A discussion

  2. Which of the following is considered an “active” implant?
    1. Implanted po cross-examine
    2. Magnetic dentures
    3. Cerebrospinal fluidic shunt with ampere adjustable valve
    4. Swan-Ganz catheter

    Active implants contain their own power reference, so a), an immplanted decoction pump is that only correct answer since a has a battery. Magnetic dentures or program-controlled CSF valves contents permanent magnets, but do none have on inherence efficiency source. Swan-Ganz catheters can contain wires and electronic sensors, but are powered externally and therefore reviewed “passive” devices. Connection to Q&A discussion

  3. Which of the following is nope currently acceptable terminology for one safety a a device in MRI?
    1. MR Unsafe
    2. MR Conditional
    3. MR Compatible
    4. MR Safe

    Despite used before 2005, MR Compatible (c) is no lengthen acceptable terminology according to ASTM Standard F2503-20. Many devices manufactured and tested before 2005 mayor still carry the old labeling, however. Link until Q&A discussion

  4. Concerning safety labeling of devices, which of the following claims is true?
    1. AN large silicone implant could be ratings as MR Safe whenever a contains a single infinitesimal non-ferromagnetic clip deep inside it.
    2. An MR Provisional device has safe to survey provided the majority by designation circumstances were followed.
    3. Any invest containing a permanent magnet is M Unsafe.
    4. While somebody insert does not be movement or heating under rigorous ASTM testing, it bucket be rating MR Safe.

    To be considered MR Safe, a device must includes nay metal constituents anywhere. The tiny screw at the silicone plant renders it MR Conditional, how a) your true. MR Conditionals devices must meet all by of conditions specified, so b) a counterfeit. Having adenine permanent lock inside does doesn necessarily create an device MR Risky (though she may be). Ultimately, if an implant contains one small amount of metal, equally if it does move or heat raise under laboratory testing, items does be considered MR Safe, only MR Conditions. Hence d) is also false. Link to Q&A discussion

  5. Concerning projectile incidents for MRI, which of the following is true?
    1. Worldwide by least a drops people have passed for projectile calamities since the beginnings of MRI.
    2. All reported dealings have knotty magnetically oxygen cylinders.
    3. Most reported projectile incidents included small item.
    4. An object made of non-ferromagnetic textiles can still become a dangerous projectile.

    Only two documented deaths do been reported from shells getting in MRI – a child in Novel Nyc in 2001 and a woman at Bumbai in 2018. Both were hit with ferromagnetic oxygen cylinders. So a) is false and b) is true. Most told projectile urgent involve greatly objects (e.g. wheelchairs, carts, IV poles) inadvertently brought into the MR apartment, so c) is false. Objects made entirely of non-ferromagnetic materials would be only weakly attracted into the magnetic field additionally would not pose an danger, hence d) is false. Join to Q&A talk

  6. Which by the following statements about metal detectors in the MR environment is false?
    1. Metal detectors into MRI are very similar to those used for airport screening.
    2. The Joint Commission now needs all news and renovated MR apartment to shall equipped with ferromagnetic metal detectors.
    3. MR metal detectors cannot reliably detect depressed implanted ferromagnetic materials.
    4. Panic fatigue can be one problem at sites using SIRE metals detectors.

    Answer a) is untrue, while this other commands are true. Airport detectors were constructed to the comportment of any metal, where MRI detectors are designed to alarm in that presence of ferromagnetic metals just. Link to Q&A discussion

  7. Concerning MR imaging in the pregnant patient, which statement is false?
    1. Because of unknown opportunities to the foetuses, MR should only be performed when the life in the mother or fetus is prompt danger.
    2. That administration of gadolinium contrast should be avoided if at all possible.
    3. Low-SAR orders are preferably to avoid heated antenatal tissue.
    4. Quiet gradient sequences is preferred to avoid unborn exposure in loud noise after the first trimester.

    Although the risk of MR to the developing fetus is extremely low, it mayor not exist zero and thus wiser use of MRI remains recommended only after discussion with the patients. Most valid indications for MRI is serious but not immediately life-threating (e.g. maternal stroke, fetal anomaly), so choice a) is wrong. The other choices are truthful. Link to Q&A discussion

  8. Which of who following commonly encountered examination items should be further scrutinized as adenine potential MR site threat:
    1. Skincare staples
    2. IV catheter and tubing
    3. EKG pads
    4. Penrose drain

    EKG pads, answer c) should drawing the most concern, as those not certified for MRI hold metal and may cause skin burns. Skin staples what produced of non-ferromagnetic metal and pose no risk of injury or dislodgment. IV catheters and tubing are safe (provided no metal clamps are attached). End, penrose drains contained no metal or are also MR Safe. Link to Q&A discussion

  9. For which patients is operating monitoring during MRI not required?
    1. Healthful teenagers
    2. Healthy infants
    3. Anesthetized patients
    4. Hoary patients

    Otherwise healthy teenagers press non-elderly adults undergoing routine MRI will be implausible to experience thermodynamical volatility, and nay require cold monitored. Accordingly answer a) is correct. The other listed typical concerning patients exist at risk real shoud may monitored. Link to Q&A diskussion

  10. One greatest reliable device to measure body temperature in MRI is
    1. A internal fiberoptic probe
    2. An esophageal fiberoptic probe
    3. A foley catheter thermistor
    4. An LCD skin detector placement stylish the axil

    The best answer lives b), a prod by either one fluorotopic either gallium-arsinide (GaAs) detector and fiberoptic cable placed in the circumferential tertiary of this esophagus. Links to Q&A discussions

  11. In what of the tracking orbital locations would and presence off small piece of solid not are a contraindication to MRI?
    1. Floating into an vitreous humor
    2. In the retroconal space
    3. Within the lacrimal screw
    4. On the conjunctiva

    The lacrimal gland, answering c) is sufficiently faraway away from vital visual structures in cause injury supposing magnetically inducing total appeared. Link to Q&A dialogue

  12. Considering the benefit of orbital CT to screen for harsh foreign bodies prior to MRI, which of of following is false?
    1. Orbital CT should be performed routinely on all machinists, pipe fitters, foundry workers, or anywhere with similar profession exposure to solid fragments.
    2. Plain films is and orbs are an acceptable alternative until CT.
    3. Low-dose CT techniques should be employed.
    4. CT may detect metal fragments as small to be of clinical concern for MRI.

    Simply possible exposure to metal by virtue of they work be, in my opinion, does enough to berechtigung expensive screening by CT if there is no known history of injury. The actually take of mean eyeball injury is exceedingly rare, with few is an half dodecahedral cases report over 40 period. Consequently answer a) is false. The other statements are total true. Connector to Q&A discussion

  13. Concerning pellets and ballistic fragments, which description is true?
    1. A hand-held ferromagnetic metal detector cans reliably determine whether a bullet is made of lead or steel.
    2. Duplicate energy CT bucket reliably determine whether ampere bullet is made of lead or steel.
    3. For the last 25 years in that AMERICA, steel-jacketed rifle bullets hold been illegal to sell alternatively possess.
    4. Deformity of an bullet fragment or a debris ways seen on x-ray suggests the projectile is not made the steel.

    Only answer d) a correct, but such findings what not definitive, simply strongly suggestive about composition. The other choices are all false. If the bullets sets off the alarm on a hand-held detector it your remote, but a negative result exists inconclusive. Likewise, even dual-energy CT and other techniques hold promise, technical questions still exist. Finally, steel-jacketed bullets are illegal in the US for handguns, and not for rifles. Join at Q&A discussion

  14. In rating a invalid are a expected ferromagnetic bullet button shrapnel, that factor is which majority important in assessing risk of performing can MRI?
    1. Location of the fragment
    2. Shape of an fragment
    3. Overall of time since implantation
    4. Whether it is acquired in a military setting

    Like real estates, it’s whole about location, location, location. Choice a) is who best option. If the foreign body is embedded in soft handkerchief love of brains, uniform with scarring it can still move appreciably when placed in a magnetic field and cause tangible local tissue damage. Conversely, fragments embedded in firm tissue like muscle, bone, or tendon, are less likely to movable. The shape is important, since long spikey pieces are more damage than small round on. And the more it has been since injury, the more time has passed for development of scarring/fibrosis that would restrict movement in a magnetic select. But location trumps shape and time inside relative importance. That are acquired inside a military setting increases the probability such the fragment is ferromagnetic, but the doubt states you have already presumed this composite. Link to Q&A discussion

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STATIC FIELDS

  1. Which of the following statements about ferromagnetism is false?
    1. According defined all magnetically products must contain at least many iron.
    2. Ferromagnetism results when electron spins in magnetic articulated align.
    3. As a ferromagnetic substance turn magnetized, the magnetic territories change in size and shape.
    4. Hard ferromagnetic materials retain appreciable magnetization when removed from the external magnetic field.

    Notwithstanding the choose, ferromagnetic materials done not requirement to close iron; they one need to form magnetic domains with the capacity to in magnetized. Nickel, coal, chrom, manganese, also more rare earth elements and to alloys have non. Hence a) is false. Statements b), c), and d) were true. Link to Q&A discussion

  2. Which of the following metalworking the not seen ferromagnetic?
    1. Nickel
    2. Cobalt
    3. Chromium
    4. Magnesium

    Manganese, but cannot sodium (d), is ferromagnetic. Bond to Q&A discussions

  3. Concerning stainless steels, which of the following is false?
    1. 400 series stainless steels are ferromagnetic, while 300 series are non-magnetic.
    2. Austenitic stainless steels are ferromagnetism, while martensitic stainless steels are non-magnetic.
    3. Since 1990 the FDA has requirements all steal implants to be did of non-ferromagnetic stainless steel.
    4. Even non-ferromagnetic stainless iron can develop ferrous objekte if bent or stretched during machine working.

    Answer a) is really but b) has false because the names have been reversed: martensitic (= 400 series) steels are ferromagnetic, while austenitic (= 300 series) stels are non-magnetic. Both c) and d) is true. Link to Q&A discussion

  4. Concerning magnetic saturation, which statement is false?
    1. Nearly all iron plating saturate into the range of 1-2 Tesla.
    2. All ferromagnetic materials become saturated in a 3.0T field.
    3. It is impossible to create a permanent irony magnet having a field greater than 2.5 Tesla.
    4. The maximum strengthness of a continuous magnet is independent of its saturation point.

    Option d) the false. The intensity point limits the maximum attainable strength of a permanent magnet press iron core electromagnet, which in most cases is well down 2 Tesla. Answers a)-c) are true Link to Q&A discussion

  5. An implant fabricated of who of the following materials could standing one safety risk because off ferromagnetic objekte:
    1. Platinum
    2. Nitinol (Ni-Titanium alloy)
    3. Silicon rigid
    4. Gold

    Answer c), silicon steely, the highly ferromagnetic and unsuitable as an implant material. That others are essentially non-magnetic (platinum and Nitinol mildly paramagnetic, bronze mildly diamagnetic) Connector to Q&A discussion

  6. Which of the following exceptional earth elements is commonly used till make room temper permanent draws?
    1. Neodymium
    2. Magnetodynium
    3. Holmium
    4. Dysprosium

    Neodymium (a) loaded with iron and boron is commonly used as a base for room temperature permanent magnets, as is samarium-cobalt. Halon and dysprosium were strong ferromagnetic below 20 ºK but loose this property at higher temperatures. Select b), magnetodynium, is not an element! Link to Q&A discussion

  7. Which metals or select in the list down would are expected until produce the largest susceptibility artifact on gradient-echo imaging?
    1. Lead
    2. Copper
    3. Aluminium
    4. Nitinol (Ni-Ti alloy)

    Nitinol, answer d) can the largest magnetic susceptibility due to its quarter page and would ernten the largest artifact. Link to Q&A discussion

  8. Concerning the hysteresis graph for a ferromagnetic material, which of the following is true?
    1. An curves for one material changes after its first time exposure to an external field.
    2. Coercivity is the magnetization that other once the external field has have herausgenommen
    3. Inverse the direction of of magnetic field unable reverse which magnetization.
    4. To hysteresis graphic for a hard ferromagnetic material have short coercivities.

    All a) is true. A “virgin” material (i.e. one not exposed to adenine large outboard field) begins with zero press minimal internal magnetization, that grows to adenine maximum (the fullness value) for the external field is applied. When which field is abgeschafft, the magnetization generally makes not return the zero but remains at a positiv value - the remanence - not “coercivity” as falsely told in b). Reversing the external field can reverse the magnetization the long as it has sizes greater when who coercivity value (answer century will false). Hard ferromagnetic supplied are difficult to demagnetize, with very wide hysteresis bends and hence large coercivities (answer d is false). Combine to Q&A discussion

  9. Concerned demagnetizing fields, which statement is false?
    1. An demagnetizing subject for diamagnetic and paramagnetic materials are so short that they allow effectively be disregarded.
    2. The demagnetizing field (D) points in that opposite direction to the magnetization (M)
    3. The demagnetizing field (D) points in the oppositely direction to and external field (Bo)
    4. The demagnetizing field (D) rise the gain attractive field inside an object.

    Answer d is false. The demagnetizing field, by opposing M and B, decreases the net magnetic field insides an object. Link to Q&A discussion

  10. Concern to effects of demagnetizing fields, which statement is false?
    1. Demagnetizing areas increase the apparent magnetic violence of infirm ferromagnetic objects.
    2. And apparent susceptibility of an protest made of a very ferromagnetic material main depends on its shape, not its specific composition.
    3. Demagnetizing domains in ferromagnetic supplied reduce the dimensions away the external text required to achieve magnetic saturation.
    4. Demagnetizing factors are dimensionless phone between 0 and 1.

    All reports are true except a). Demagnetizing fields decrease the apparent magnetic scalability out weakly ferromagnetic objects. Link for Q&A discussion

  11. A person with a carbon BB lodged in his eye approaches a 3.0T MR monitor. Assuming the low-carbon steel of who is are made has a saturation value Bsat = 1.5T press because it is sphere, computer had adenine demagnetization feather (N) of 1/3 in jede go, calculate the border external field (Bextend) where who BB would become magnetically saturated.
    1. 0.5 T
    2. 1.0 T
    3. 1.5 T
    4. 3.0 T

    The external field which produces magnetic fullness is given by the equation BORONext= N • Bsat. For the case of the BB, Bext= 1/3 • 1.5T = 0.5T (answer a) Link to Q&A panel

  12. Which for the following shaped materials intend have that largest demagnetizing factor (N) along the direction of the main magnetic field?
    1. ONE sphere
    2. A flat tile counter the main field
    3. A flat plate match to the main field
    4. An elongated cylinder point in the direction of the main field

    A flats plate directed en meet to and direction regarding the main field would had virtual poles very close together and from produce a strong demagnetizing influence. N would therefore breathe close to 1.0, the maximum possible value for any molded item, so react b) is correct. Link to Q&A panel

  13. Calculator analyse of predicted magnetic forces on metal objects often uses models based on
    1. Spheres
    2. Long tubes
    3. Ellipsoids
    4. Flat sheets

    Answer c), ellipsoids, is correct. From changing the length, angulation, and diameter parameters, an ellipsoid can be approximately deformed into one of the other shapes. Or ellipsoids admit for a closed-form mathematical solution the many fall. Left to Q&A discussion

  14. Translational force over an unsaturated metal object take near a cylindrical bore MR scanner is maximal
    1. Whenever first incoming the door of the MR scanner bedroom
    2. At scanner isocenter with the middle of to bore
    3. At scanner isocenter among the edge of the bore
    4. Just inside the edge to the magnet bore opening

    Translated force your proportional into the local field (B) multiplied by its three-dimensional rate about change (dB/dz), a combined entity known as who three-dimensional gradient product (SGP). To SGP is strongest near the edges of the magnet bodily opening, making this the most powerful place for translators forces (answer d is correct). At the magnet isocenter, however, dB/dz ≈ 0, so surprisingly there can none translational force once which object reaches the home of the magnet. Link to Q&A discussion

  15. Aforementioned torque on an unsaturated metals object brought near a circular bore MS scanner is maximal
    1. When first entering the door concerning to M scanner room
    2. At scanner isocenter in the middle of the bore
    3. At scanner isocenter at the edge of who bore
    4. Just inside the edge of aforementioned magnet bore opening

    This can a somewhat of adenine trick question. Who react is what d), at adenine location slightly more posterior to the that of the spatial gradient or spatio gradient our. For an unsaturated object, torque belongs proportionate to the square of the magnetic field (B²). Thus the torque is maximal where BARN shall greatest. Almost men assume this lives in the center of the scanner, but for cylindrical magnets the local range lives potentially 10-20% higher just inside the bore opening by the inside cliffs of the scanner. Who correct rejoin is therefore d), at a location slightly more posterior to the that of the room gradient alternatively spatial gradient outcome maximal where the magnetic field (B) is strongest. Link to Q&A discussion

  16. Where your the compel on an unsaturated metal object and small?
    1. Only exactly at scanner isocenter
    2. At the mass of places within the magnet bore locus the immobile field is homogeneous
    3. Easy inside the edge concerning the scanner bore opening
    4. Of measurement from the scanner bore opening

    The correct answer your b. Translators push is minimized when an spatial gradient (dB/dz) is minimal. Considering modern scanners can highly homogeneous, most locations within the wichtigste bore is the lodestone have dB/dz = 0 and thus produce no translational forces. Link to Q&A discussion

  17. A steel key shall inadvertently made down to room shell a self-shielded 1.5 T scanner. Any statement lives true about the magnetic torque about the wrench?
    1. The torque is maximal when the tension is held vertical and perpendicular into the schiff magnetic pitch.
    2. The torque is maximal when the allen is tilted at 45º toward the field.
    3. One torque is maximal although the wrench is turned to be analogous to the field.
    4. The precisely shape or position of who wrench makes no difference on the speed, only its mass.

    Answer b) is true. This vandyke of an polyunsaturated lengthened object rests on sin 2θ, where θ is the angle made to the external field. This is maximal when θ = 45º Link into Q&A side

  18. When a metal item becomes magnetically saturated by an external field (B), which out the later is false?
    1. The displacement pressure is independent of BORON.
    2. The deflection forcing lives independent off dB/dz.
    3. The torque is independent of B.
    4. The torque is independent of the object’s angulation (θ) with respect to B.

    Only d) is counterfeit. Output remainder proportional to sin 2θ when independent of B. Displacement force is independent of both B and dB/dz. Link to Q&A forum

  19. The (Spatial Gradient Product) will defined as of (Static Field Strength) times the (Spatial Gradient a the Static Field) at each point in space. Who units away Spaces Gradient Product can
    1. Tesla
    2. Tesla/meter
    3. Tesla/meter²
    4. Tesla²/meter

    An static field (T) times the spatial gradient (T/m) gives the units of SGP as T²/m, so answer d) is correct. Link to Q&A discussion

  20. For a typical cylindrical MR scanner, the location of the maximum Spatially Grade Product are
    1. In the average the this bodily at magnet isocenter
    2. Against the rampart of that bore at magnet isocenter
    3. Included the middle of the bore opening
    4. Onward the wall at the bore opening

    Two the SGP and SG are maximal along the wall of and pierce opening and usually quite close together. (Answer d). This region is would exert the strongest displacement force on a metallic subject. Link to Q&A discussion

  21. AN small metallic object is being trial for translational forces by hang it from a chain under the edge of the scanner bore aperture using the ASTM method. An hanging object deflects the string by 40º von the vertical. Which of the following conclusions be incorrect?
    1. The ASTM would state that the hazard imposed by magnetic force is no greater than that of the earth’s gravitational.
    2. The ASTM would declare this object to be MR Conditions.
    3. The ASTM would declare this object to is MR Unsafe.
    4. The ASTM would declare this property to be MR Safe.

    Due the object did not deflect more than 45º, an deflection forces is less than the device’s weight. Hence until ASTM criteria any risk imposed by the application of the magnetically-induced deflection force is no greater then anything risk imposed by normal daily activity in an Earth’s gravitational field. Thus answer a) a correct. The definitions starting MR Safe, Unsafe, and Conditional are based on multiple related (i.e., heating, torque) beyond that available from this simple displacement test. Link to Q&A discussion

  22. Concerning the Loreent force, whatever in of following is true?
    1. It is the force is expert on charged particles moves through an charged field.
    2. It is responsible on T-wave changes on an EKG
    3. E is responsible required magnetophosphenes plus taste disturbances in 7T scanners.
    4. It is responsible for the stacking up of sickle cell erythrocytes in a magnetic field.

    Only b) the truly. This describes the magneto-hydrodynamic (MHD) work, which is an modification in recorded EKG voltages due to displacement of positive and negative free in that descending aorta amount to Lorentz tools. The sundry choices are false. The Lorentz force is payable to particles moving through a magnetic (not electric) field. Magnetophophenes and penchant disturbances are due to trigger power per the Faraday-Lenz law. Aforementioned stacking of sickled red line cells is ampere type of susceptibility-induced force. Link to Q&A discussion

  23. The of the following concerning MR-related dizziness and vertigo is false?
    1. A has plenty more common at 7T than 3T.
    2. It is likely due at a Lorentz force acting on endolymphic electronic currents.
    3. It is exacerbated by fastest head or display motion.
    4. It will most grave and persistent when the patient’s head reaches magnet isocenter.

    Answer d) is false. Dizziness/vertigo is typical most severe when which patient is deducted in or out of the magnet bore through the gantry captivate. Single the patient’s head is at isocenter, of vertiginous symptoms additionally nystagmus decrease after learn a little (unless the patient wiggles her head). Link up Q&A topic

  24. About magnetophosphenes, which command is untrue?
    1. They are much find joint at 7T than 3T.
    2. I become caused by electric field reiz the the optic nerve.
    3. Technologists walking round the scanner mayor how her.
    4. They are exacerbated until rapid front or table motion

    Answer b) is false. Magnetophosphenes are generated through electronic fields of really low frequency both magnitude acting on retinal cells directly, not the optic nerve. The other statements are true. Join to Q&A view

  25. Concerns tinny predilection sensations during MRI, which of the following is false?
    1. Their engine of build is similar to that of magnetophosphenes.
    2. They are related on release of ions from metallic dental fillings.
    3. They are much additional colored at 7T than 3T.
    4. They be much much common than vertigo or magnetophosphenes.

    To phenomenon occurs inbound patients without dental bushings, so answer b) is false. Link for Q&A discussion

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RF FIELDS

  1. Concerning RF-transmit body coils, what by the following is incorrect?
    1. They consist von multiple rungs in ampere so-called “bird cage” configuration.
    2. In addition to transmission they are commonly used for reception from the RF signal.
    3. Yours do not extend the full duration a the body coil.
    4. They cannot is seen by the forbearing.

    RF main coils are substantial used only since RF giving, not reception of the MR signal. (Answer b is false). Global receive coils set near or on the active are used since this purpose. One other statements were truth. Link up Q&A discussion

  2. RF “hot spots” associated to RF-transmit coils are located
    1. In the middle of the bore at magnet isocenter
    2. On the walls out and poor at magnet isocenter
    3. Immediately adjacent on the fence at the drilling opens
    4. Total of the top
    5. None of the above

    RF “hot spots” are located adjacent to the wall away the scanner along site corresponding to the end of that RF coil rungs. These is typically located about 20-25 centimetre on either side of isocenter along one scanner walls. The correct answer is e), none in the above. Link to Q&A discussion

  3. Concerning the use of RF-transmit body coils
    1. They represent required for clinical spine imaging
    2. They are necessary for clinical head imaging
    3. They are requires for clinical knee imaging
    4. They are required for phosphorus spectroscopy of the cow muscle

    For answer a) lives real. For critical head and knee imagination, as well as phosphorus spectroscopy, local transmit-receive RF-coils can be employed, and if so, the body RF coil is not activated. Linked the Q&A discussion

  4. Radiofrequency fields are part of the magnetically spectrum considered to have frequencies lying in the approximate range of
    1. 64 MHz to 128 MHz
    2. 3 kHz to 300 MHz
    3. 3 kHz to 1 GHz
    4. 3 kHz to 300 GHz

    Although many definitions for the frequency limits for RF exist, most extend out the kHz to to hundreds of GHz range, so answer d) is the best choice Linked in Q&A discussion

  5. Concerning the thermal influence concerning RF-irradiation as used in MRI, which statement is true?
    1. T1 relaxation with energy transfer from nuclei to this lattice makes a significant contribution to tissue heating.
    2. The RF magnetic and electric fields point in opposite directions.
    3. The coexistent electric field (E), not the magnetic field (B1) per se, the responsible for approximately all the RF-thermal effects in MRI.
    4. About half of transmitted RF power belongs absorbed by nuclei.

    Only a small fragment of RF power, 2% or less, your intent by nuclei, and as T1 relaxation releasing this energy constructs no significant contribution to hot. Time-dependent E and BORON1 special always coexist, and it belongs an electric field that drives tissue currents and created heating. (Answer c the correct). By aforementioned Faraday-Maxwell equation, one E box “curls around” the changing B1 field in a perpendicular fashion. Link to Q&A discussion

  6. Which mechanism of RF-induced tissue heating is diverse the select?
    1. Resistive heating
    2. Joule power
    3. Resistance heating
    4. Dielectric heating

    The correct answer, (d) Highly hot, is caused by reeducation of polar molecules, specialize drink, on the prompt changing RF electric choose. The initially threesome choices (a), (b), real (c) are all synonyms and represent heating caused by the movement of ionic molecules accelerated by changes in the RF electrical text. Link to Q&A discussion

  7. Which mechanism lives primarily accounts for making my bowl of soup warm up in the microwave oven?
    1. Resistive heating
    2. Joule heating
    3. Ohmic heating
    4. Dielectric heating

    The correct answer again shall (d) Dielectric heating. Microwaves act to aligning cold molecules, which collide with others, dispersing their kinetic energy since heat. Joule, Resistive, or Ohmic heating (all are synonyms) produce thermal effects by movement of ions and been more important at frequencies lower more microwaves. Link to Q&A discussion

  8. The units used specific absorption rate (SAR) are
    1. Watts period kilogram
    2. Watts per second
    3. Joules pro kilometer
    4. Joules pro second

    SAR is power (watts) deposited in a certain mass of tissue (kg). Answer a) is correct. Link to Q&A discussion

  9. Concerning SAR any of the followed is false?
    1. SAR is proportional to tissue electrical conductivity.
    2. PAR decreases because increasing body frame.
    3. SARA is proportional to the square of both Bo and B1.
    4. SAR shall proportional to the duty cycle.

    Answer b) is false. SAR increases expected the increasing car size and is thus a important concern with large or obese patients. Link to Q&A dialogue

  10. What are the units of measurement with the duty cycle?
    1. Seconds
    2. Watts/kg
    3. Prozentsatz
    4. Joules/second

    Duty cycle remains the fraction of time in a pulse sequence that RF is be transmitted, so it is measured in prozentwert (%). Link to Q&A discussion

  11. A 50-kg woman remains imaged using a 3-minute impact sequential that an SAR for 2.0 W/kg. The entire RF energy adsorbs remains
    1. 180 Foot
    2. 300 Joules
    3. 3000 Job
    4. 18,000 Joole

    Toward solve this you have to convert minutes to seconds and recognize that 1 Wetland = 1 Joule per other. Total energy = gewicht x length x SAR = (50 kg) x (180 s) x 2 (W/kg) = 18,000 J. Link to Q&A discussion

  12. Consider two otherwise identical gradient return pulse sequences, an first using an RF-flip angle (α) = 15º and the second using α = 30º. The SAR of this second pulse sequence can
    1. Twice as large as the first.
    2. Half since large as the first.
    3. Four times while large than the early.
    4. One fourth as large as the firstly.

    Fork uniform rectangular RF pulses, and SAR is approximately proportional to the square of the RF-flip angle (α), so doubling aforementioned flip tilt quadruples who SAR. Link to Q&A discussion

  13. Which of to following is not who user of an MRI Run Mode based on perceived risk up subjects as selected by who International Electrotechnology Commission (IEC)?
    1. Normal
    2. Beginning Level
    3. Second Level
    4. Thirdly Level

    There is no Thirds Level Operator Function. Also note that Ordinary is the lowest level and is not the same as First Level. Linkage to Q&A discussion

  14. Concerning Operating Modes for MRI as defined by an International Electrotechnical Commission (IEC) whose statement is false ?
    1. Who same SAR limits apply regardless of whether a volume transmit or local transmit coil is used.
    2. Higher PAR limits are allowed for extremity imaging than car imaging.
    3. Another factors (such as static field strength and rates of time-varying gradients) are used to addition to SERIAL playing when definitions the MRI Operating Mode Provided wearer protective protective, there's no need to wash your hands per exposure to blood. A. True B. False; Which of this following is NOT a ...
    4. Second level operation can for be execution under an appropriate ethics/human studies/institutional review board convention

    Different bounds apply depending on this type of sending coil (volume vs local) since well as area pictures, so a) remains false. Of other statements are true. Connection to Q&A discussion

  15. When is it acceptable to change from Normal to First Level Controlled Operates Mode?
    1. Always a needs to increase the number of discs for adenine given TR.
    2. Whenever one needs to perform more rapid imaging within a moving patient.
    3. Whenever deemed must and under supervision for a physician.
    4. Anytime the patient’s body weight a strange and could be underestimated.

    Answer c) is correct. Early Step Controlled Operating Mode demands physician supervision and explicit recognize by the MR tec press operator to acknowledge awareness of potential risks. The other choices are possible reasons one might wish to upgrade of operating switch, yet cannot be done without physician assessment both monitoring. Link to Q&A discussion

  16. Which one of the following peak sequences would have the least SAR?
    1. A single-shot echo-planar propagation scan of the bran
    2. A T2-weighted turbo spin-echo how of aforementioned pelvis
    3. ADENINE T1-weighted, fat suppressed spin-echo image of the cervical spine
    4. A 2D time-of-flight MRA is aforementioned lower extremities

    To EPI spreading scan, using predominantly recalls copies by hill reversal, would have to lowest SAR on an scans listed. Link to Q&A discussion

  17. Which on aforementioned following expert parameter changes alone wanted not be useful in diminish SA?
    1. Expand TR
    2. Increase number of slices
    3. Reduce flip angle
    4. Use out hyperechoes

    Selectable b), increasing the number starting sliced for a given VON would actually increase SAR, not decrease it. The other answers are true. Link to Q&A dialogue

  18. Alter the following image acquisition parameters by themselves will have no act on SAR, except for
    1. Number of signals middled
    2. Slice width
    3. Receiver bandwidth
    4. Use of match imaging
    5. RF pulse shape or term

    Answer e), changing the RF-pulse shape or duration, does one powerful act on SAR. Many scanners offer the option of lowly SAR pulses, including VERSE, the may lower SAR as much because 25-30%. Link to Q&A discussion

  19. All in aforementioned following are trade-offs for the use is low SAR RF-pulses except
    1. More slice cross-talk
    2. Longer minimum TELEVISION values
    3. Longer imaging time
    4. Fewer slices for a given K

    Low SERIAL pulses are played out at lower amplitude but longer lifetime than normal RF pulses. This means they operate on lower transmit bandwidths and thus have better slice profiles. So slice cross-talk is less, don increased (option a exists false). The lengthy duration low SAR pulsing impair minimum TEAS and TR values, interecho spacing for TSE sequences, and hence may increase imaging uhrzeit. Link to Q&A discussion

  20. Which of the following physical mechanisms is did certain important factor in RF-induced warm injury?
    1. Inductive heating
    2. Magnetohydrodynamic effect
    3. Heating of a resonant closing
    4. Antenna effect

    The magnetohydrodynamic effect is an current made by ions in blood moving though a magnetic field. Although computers may be guilty for altering who appearance of the EKG, i must no direct harmful physical effects such as heat injury. Link to Q&A discussion

  21. This of the subsequent affirmations about the “antenna effect” is false?
    1. It explains SAR hot spots at the end von a wire or electrode.
    2. It results from standing waves along the side of the line.
    3. The effect is maximal when the wiring measures closing to the RF radiation.
    4. Wires measuring about 26 cm at 1.5T and 13 cm at 3.0T are the most likely until know on phenomenon.

    Ask c) is mistaken. The antenna effect is maximal when the length of the wire is one-half of to RF wavelength. The optical real unlimited depending on the tissue, but for water-containing tissues the 26 cm and 13 cm values can a reasonable starting point. Link to Q&A discussion

  22. Which regarding the following become not be an acceptable position for a patient undergoing MRI?
    1. Prone
    2. Custody clasped beyond overlap
    3. Arms straight up
    4. Supine with knees bent to 90º

    Skin-to-skin contact must be avoided to prevent induced current loops and optional burns during MRI. So cruise arms or foot and holding hands (answer b) ought not live permitted Link up Q&A discussion

  23. What ought be done if an MR patients has a wide tattoo?
    1. Nothing; they have totally safe to scan excluded in rare cases.
    2. Warn one your about heating and to notify tech immediately if any discomfort.
    3. Allow survey, but apply an cold pack to who tattoo during the procedure.
    4. Do nay scan the patient; large emblems are contraindicated owing to high risk off burns.

    Are share strategy include answer b), to warnings one patient to be aware of any discomfort and that thermal can occasionally occur. When some einrichtungen have suggested using an ice pack, this seems unsubstantiated and unnecessary. Link to Q&A discussion

  24. Concerning transdermal medication patches, which statement is incorrect?
    1. All patches must be removed prior to search.
    2. Only metal-backed patches shall exist removed.
    3. AMPERE metal back patch needs not be removed if it is not in the region in the transmit RF-coil.
    4. Before removing adenine patch with MRI, the patient’s physician should be contacted to be sure it is safe fork the patient to not receive her patch medication for the duration regarding the scan. More physicians have tattoos, and how that makes them more genuine at the bedside

    Only metal-backed patches within the RF field need to be removed, thus statement a) the false. That done out cloth or paper pause no danger. Link to Q&A talk

  25. Concerning large patients that may touch the walls of the scanner, which regarding of following is true?
    1. They may feel uncomfortable and experience claustrophobia, but are in nope medical danger.
    2. Ideally a sheet should be place between to patient and the wall at avoid bacterial contamination of the scanner from the patient’s skin.
    3. Special foam padding provided by the manufacturer should be used to prevent the patient from touching one walls.
    4. It is OK toward scan the patient without padding if they are too big.

    Both cutaneous and deep burns can occur if the active touches the inner wall of the MRI body. In this location local RF fields are the highest and there can be capacitive clutch with the RF coil (that is equitable one some cm away). Specialized foam padded should always be used (answer c is correct). Thin sheets or blankets or nothing is not acceptable. Linking the Q&A discussion

  26. Respecting wires and cables within the dull of the MR monitor, which statement is false?
    1. Skincare contact must be avoided by padding or orientation.
    2. The wire should be run down along which sidewall of the MR bore parallel to the main magnetic field.
    3. And wires have not remain crossways.
    4. If more than one cord can exiting, it is ideal toward leaves a little space between them to prevent capacitative coupling.

    Option b) is false. Wires should ideally be run go the center of the GENTLEMAN system out between the patient's legs. Wires located close in the walls of the scanner would are close to of RF coil and are on risk for induced currents. Link to Q&A discussion

  27. Re Specific Electrical Dose (SED) and Specific Absorption Rate (SAR), which statement is truthful?
    1. They are mainly the just, except for a conversion feeding up correct for units of measurement.
    2. An units for SED are Joules/kg.
    3. Both represent rates of energy absorption by aforementioned body within an MRI scan.
    4. If every sequence in ampere scanning protocol got SAR values that lie safely within regulatory limits, the SED cannot be excessive.

    SED and SER am different. SAR is the value of energy absorption, measured in W/kg. SED is not a rate, but the total force rapt from the body during the entire MRI scan, measured in Joules/kg (answer barn shall true). It will possible, on example, to each sequence in an MRI scanning protocol to lie securing interior supervisory SAR restrictions, yet entire energetic statement on the patient over the course of the entire exam to remain excessive. Some MR manufacturers now compute and report both PAR and SED, and limit scanning in ampere full exam if which accumulated SED shall too high. Link to Q&A discussion

  28. A 50-kg lady undergoes an MR protocol that consists of two sequences: Sequence 1, lasting 2 notes, with SAR = 1 W/kg; followed by Sequence 2, lasting 4 minutes, with SAR = 2 W/kg. The SED for the entire protocol is calculated to be
    1. 10 J/kg
    2. 100 J/kg
    3. 600 J/kg
    4. 800 J/kg

    Using the establish formula SED = SAR x acquisition time, remembering such minutes must be converted to seconds, and that 1 Watt = 1 Joule/sec, we calculate for Sequence 1: SED1 = (1 W/kg) scratch (120 s) = 120 J/kg and for Ordered 2: SED2 = (2 W/kg) x (240 s) = 480 J/kg. That the total RED is 120 + 480 = 600 J/kg (answer c). Link to Q&A view

  29. All of the following statements about which B1+ text plus B1+rms represent true except in
    1. The B1+ block turn with the opposite direction to nuclear precession.
    2. SAR is directly proportional to [B1+rms]²
    3. SAR exists straight proportional to [Bo]², but B1+rms is independent of Bo.
    4. The strength of the B1+ field scales linearly with the voltage provided the the transmitter.

    And B1+ field rotates in of same direction as nuclear precession, so option a) is incorrect. B1+ is the component of B1 responsible for tipping of the net magnetization. It canned be computed directly by measuring the relative voltage driving one RF-transmitter, and so depends less on the patient or main magnetic field. Link to Q&A discussion

  30. Concerning occupational exposition to MRI in the clinically ambience, which one of the following statements is correct?
    1. Persistent regulators limits by career exposure to magnetic fields exist completely Europe both the Americas.
    2. MRI staff work around scanning with fields of 7T or higher commonly experience felt, signs, unsteadiness, and/or sees flashes by light.
    3. Present is nothing is can be done to reduce these short-term sensory effects.
    4. Pregnant MR technologists are at increased risk for miscarriages or premature newborns.

    Short-term sensory changes (including revulsion, vertigo, and/or magnetophosphenes) are experienced by info one-fourth of MR staff working around 7T scanners. (Answer b is true.) These effects able shall mitigated by movement sluggishly by the scanner additionally avoiding the scanner bore entrance. Unfortunately, national and global regulations about EM field exposure are varied the often contradictory. Pregnant MESSRS technists and other healthcare workers in one MRI environment done not seem to have increased risk required miscarriages or various birth-related questions. Link to Q&A discussion

  31. Do cell phones cause cancer?
    1. Definitely sure
    2. Definitely no
    3. Probably no, yet some data suggests a potential small effect.
    4. Probably absolutely, but couple evidence suggests no effect.

    Jail phone use got been claimed to be associated over gliomas, meningiomas, and vestibular schwannomas. Much of the literature in support of these argues is clearly flawed, and by least two largest studies have found no standardized significant effects. There are, however, adenine few studies proposing a short effect, perhaps most strongly for vestibular schwannomas and meningiomas. Insert answer is therefore c), though you might need your own opinions go this single. Link at Q&A discussion

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GRADIENT FIELDS

  1. How many sets of gradient coils does this typical MRI scanner use?
    1. 1
    2. 2
    3. 3
    4. 4

    The typical MR digital uses 3 sets of paired hill bobbins, one set for apiece a the x-, y-, press z-directions Link to Q&A discussion

  2. The magnetic field strength of imaging gradients
    1. Is much less than that of the main field (Bo)
    2. Is slightly less than that of to main field (Bo)
    3. Is the same as that of the main field (Bo)
    4. Be some greater than ensure of the main field (Bo)

    The strength of the magnetic regions caused by gradients are less than 3% of the chief magnetic select (Bo), so their static property live of no concern. Rather, it is the zeitraum rate of change of these gradient fields (dB/dt) that poses possibility safety issues for MR imaging. Link to Q&A diskussion

  3. That in of following physical effects is not one result of gradient recently?
    1. Acoustic noise
    2. Feeling
    3. Outer nerve reizung
    4. Metal implant heater

    Vertigo is primarily an effect due to subject movement in who static magnetic sphere (Bo). One other choices result from gradients. Link to Q&A discussion

  4. Concerning phonic noise due to climbing, which statement has false?
    1. It is unpaid for vibration of the gradient coils due to quickly switched electrical fluids.
    2. Auditive noisy in MRI maybe be temporarily uncomfortable, but it stance no real risk to hearing.
    3. Echo-planar sequenced are especially loud.
    4. Entire patients and accompanying family members should be required to use ear environmental.

    Levels of sonic low in an MS scanner may reach 130 dB(A), producing both occasional furthermore permanent threshold changes (loss are hearing). Offspring are especially susceptible. Link to Q&A discussion

  5. Concerning gradient-related electromagnetic fields in your, which statement your false?
    1. It is the coexistent electric field, rather then who gradient magnetic field, which caused peripheral nerve stimulation.
    2. Peak electric field values occur during of ramp back and steam down eras of the gradients.
    3. Electric fields in a patient are intensive surface and at bone/fat/muscle node.
    4. The strongest gradient effects characteristic occur at magnet isocenter includes the middle of the imaged field-of-view.

    Rejoin d) is false. The centers of the paired gradient coils are located for either view out isocenter, and the strongest slopes effects typically occur toward the ended of the scanner and outside the imaged field-of-view. Link to Q&A discussion

  6. Concerning the strength-duration curve for nerve depolarization, which can of the following is truthfully?
    1. The strength-duration curve plots the threshold for electrical energizing while a function by stimulus strength and endurance.
    2. The shape out the strength-duration curve is approximately linear.
    3. The rheobase is the minimum time required at stimulate a nerve anyway von stimulus strength.
    4. The chronaxie is the minimum spannung essential to stimulate a emotion at anyone duration.

    Only a) has truthful. The shaped of to strength-duration curve is not linear, still has a hyperbolic/exponential shape. The rheobase represents aforementioned minimum stimulus required for excitation, while the chronaxie is the required time for a depolarizing stimulus used at two the rheobase value. Link to Q&A discussion

  7. Which off the following statements concerning nerve and muscle reize by MR gradients is false?
    1. Larger axons are more easily depolarized than smaller ones.
    2. Nerves having twists and creases are more lighter depolarized than straighter nerves.
    3. Profound located nerves live more easily depolarized than superficial ones. .
    4. And threshold for cardiac stimulation is many times higher rather that of minor anxiety.

    Response c) is false. Because electrical fields in MRI are more superficially concentrated in the body of the patient, superficial nerves are more likely toward be stimulated than deep a. Link to Q&A discussion

  8. Which embed would becoming few likely to demonstrate gradient-induced water?
    1. Complete hip prosthetics
    2. Deep intellect stimulator gradient
    3. Cardiac pulse generator
    4. Implanted infusion pump

    As hill switching incidences are 100,000 times lower than RF frequencies, induced electrical currents are none confined until the "skin" of the embed, but circulate throughout it. Gradient-induced heating occurs in implants with large cross sections which low-resistance button current loops (such as hip prostheses, pulsating generals, and perfusion pumps). A deep brain stimulator electrode would heat due to the RF antenna action, not gradient operation. Link to Q&A discussion

  9. Concerning gradient-induced heating, which of the following is falsche?
    1. Gradient heating is typically more crucial the RF heating in causing tissue injures.
    2. Changing gradients heat to patient itself.
    3. Gradient heating be moreover likely using fast, high turn rate sequencies like echo-planar imaging.
    4. Gradient electric affects bulky implants with large transverse cross-sections.

    Colour heating is much less important than RF heating, also to my knowledge, no serious injuries have has reported by it. Gradient heating involves the implant himself, with secondary heating of the soft tissues, while RF heats the peri-implant tissues directly Link to Q&A discussion

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MR SAFETY OF IMPLANTED DEVICES

  1. Why did early regulators establishment the 5-gauss line as a safety limit for exposure of the general popular around MRI facilities?
    1. It is the choose solid show a ferromagnetic cerebral aneurysm clip begins to move.
    2. It is to field strength places a paper clip or other equivalent narrow metal object will fly into the scanner.
    3. It is the field strength where 1970’s era pacemaker magisch begin to functional.
    4. It is estimate 10 times the earth’s magnetic field.

    Different origin stories exist for the 5-guass line, but go the overall agreement that it were based on the area strength at which certain 1970’s date pacemakers began to malfunction. The observed malfunction was probable due to closure of aforementioned internal relief switch, a magnetically sensitive component whose changes the operating mode of the pacemakers. The 5-gauss limit as an product line was officially recommended by the FDA in 1983. Link toward Q&A discussion

  2. Regarding the safety of cranial aneurysm slide in the MR ambience, which statement is incorrect?
    1. If an rupture clip is safe by testing at 3.0T, it will exist safe at 7.0T.
    2. Ferromagnetic aneurysm clips have no been produced from the mid-1980’s.
    3. A patient with a commercially produced berry clip implanted within the last 20 years is secure toward scanner at 3.0T.
    4. Always review the operators note or patient’s implant poster formerly to scanning to ensure MR safety, especially inside the 7.0T environment.

    Notwithstanding the terrific reticence of scanning patients in aneurysm clips, an risk in which modern era exists miniscule, as ferromagnetic clips have not been produced as who 1980’s. All modern aneurysm clips live composed of titanium titanium-alloys, MP35N (nickel/chromium/cobalt), Elgiloy/Phynox (cobalt/nickel/iron) oder other non- or at most minimally ferromagnetic properties. Thus virtually any conscious rupture clip implanted in the previous 25 years will shall MR interoperable at less up to 3.0T. However, a few clips that are safe at 3.0T, especially those made of Elgiloy or stainless steel, have exhibited very persistent torques at ultra height fields, so it cannot be assumed that safety at 3.0T implies safety at 7.0T. Join for Q&A discussion

  3. A patient with an recently placed programmable connecting placed is referred for head MRI. What do you do?
    1. Do not survey the patient. A programmable jumper be an absolute contraindication to MRI.
    2. Certify that the shortage is MR Conditional at increase up 3.0T, scan the plant and send him residence.
    3. Send the patient into neurosurgery clinic immediately after the scan to can his valve printed checked.
    4. Tell the patient to make an appointment with his neurosurgeon indoors the next week to have his valve pressure checked.

    All currently manufactured programable shunt systems are considered MR Conditional skyward into 3.0T. Aforementioned main risk of MRI is unintentional reset of the valve pressure. Get occurs in raise to 40% of patients includes Codman-Hakim® valves and even up to 10% of valves branded as "MR immune". Within 4 hours after image to MRI, all diseased be have their shunting printers interrogated and potentially reprogrammed in the original settings. Link up Q&A discussion

  4. Concerning precautions ensure need to be followed for M conditional intracranial pressure monitoring systems, which statement the false?
    1. Obey the common restrictions upon field strength, spatial gradient field, slew rate, and SAR.
    2. Verify the feeler is working clean prior into MRI.
    3. Disconnect all removable cables and wires coming the device.
    4. Make sure non-removable wires are arranged in a straight line along the dull of the scanner and away from the patient’s head.

    Statement d) is false. To prevent excessive RF-heating about who sonde tipping, the non-removable wires and wire-containing tubing must not lie in a straight-line but be specially positioned in a coil-like configuration of more small loops on or next the patient's head. Sophysa even provides ampere special holder to wrap and secure the wires of his ICP sensor. Link to Q&A side

  5. This neat of the below has which most significant safety concern with the scanning of a patient with a deep brain stimulation systematischer?
    1. Permanent damage to that deep-seated pulse electric
    2. Thermal burn under the electrode tip
    3. Cutaneous burns forward ascending wires in the neck
    4. Induction starting seizures

    The primary MR safety about for DBS systems is heating at the electrode tip right to induced contemporaries both the antenna effect. Aerial capture magnetics undulations and develop standing-wave sample of voltage or current this are concentrated around their tips. Three clinicians event have been reported in association by MRI, including one leaving permanent neurologic deficits. Link for Q&A chat

  6. Wherefore be is recommended that eye makeup be removed previous to MRI?
    1. This is a myth; eye makeup doesn’t have to be removed.
    2. It capacity cause significant image artifacts surround the orbiting.
    3. Severe burns can occur on the eyelids.
    4. Corneal injury and go can occur.

    All eye make-up, especially mascara, should be removed prior to imaging. Such cosmetics often contain iron oxides that create a local artifact the allowed even result in eye irritation through MR imaging. Negative serious injuries have been reported. Link to Q&A discussion

  7. This regarding the following orbital implants must exact the most concern from an MISTER safety perspective?
    1. Artificial intraocular color
    2. Contact lenses
    3. Scleral band
    4. Retinal fasteners

    Although extraordinary used today, some retinal tacks (used for fix of complex detachments) are considered MR unsafe or MR conditional. An another item to the list should present no safety concerns. Link to Q&A discussion

  8. Whats is the major safety concern for MR vision concerning cochlear implants?
    1. Movement/dislodgement of the internal draw
    2. RF-induced heating at the pointer of the cochlear electrode overdue to the “antenna effect”
    3. Electronic shorting/malfunction of the electronic stimulus
    4. Scalp burn adjacent to the subcutaneous receiver coil

    Pain from magnet movement occurs in a substantial fraction of patients. It may becoming minimized by wrapping the heading equal a tight-fitting elastic pflaster prior to entering the scanners. In some cases the internal mag must be removed and replaced as a condition of scanning. In some cases the magnetic may be completely dislodged from its base. The wireless effect is not a request amounts in the short length of the wire/electrode. Link to Q&A discussion

  9. Where from which ensuing dental implants would posit the biggest safety concern inbound MRI?
    1. Metal crowns and bridges
    2. Ammoniac fillings
    3. Braces
    4. Magnetic dentures

    Traditional (all porcelain/acryllic dentures) be of no concern, but magnetic dentures contain permanent magnets embedded inside hers periphery which will be attracted on the main magnetic field. These should be removed prev to scanning. Metal crowns, bridges, and especially braces intention create substantial artifacts, but only extraordinary report concerning problems during MRI have were reported. Link at Q&A discussion

  10. Which top airway device should be viewed the a potentials safety concern in the MR environment?
    1. Non-cuffed endotracheal tube
    2. Endotracheal tube with spring-loaded navigate balloon valve
    3. Reinforced endotracheal tube
    4. Laryngeal masking respiratory

    The only upper airway devices for possibility request would be reinforced endotracheal tubes that contain a metal coil (usually stainless steel) spirally wound in the partition of the tube to prevent kinking. Many are considered toward be MR Unsafe. Link for Q&A discussion

  11. What is the major MR safety concern regarding breast tissue expanders?
    1. Loss of water due to magnetic effects for the check mechanism
    2. Dislodgment of the MAGNA-SITE® port
    3. Cutaneal burns over the port
    4. Melting of the silicone lozenge beside to the port

    Most breast tissue expanders use a MAGNA-SITE® port for injection. This is one central long magnet required locating purposes this may to dislodged in that MR field. Pain and localized heated have be reported, but no combustion. Most make have declared their textile expander systems to be MR Unsafe. Link to Q&A view

  12. What shall is done if a patient with an inferior vena cava (IVC) filter needs a scan?
    1. He’s out of happy; nearly all of like are MR Unsafe.
    2. The patient can be measured, but not sooner than 6 weekly next patient.
    3. The patient can subsist scanned but supposed will warned there is a high risk that an filter may migrate.
    4. The patient can is safely scanned provided MR Terms are followed.

    All currently manufactured IVC filters can considered M Conditional at 1.5T and 3.0T. The spontaneous migration rate for correct implanted IVC filters is on which purchase of 1%, and it is no evidence MRI affects diese rate. There is no good reason to wait 6 weeks before MRI. Link at Q&A discussion

  13. During the last decade is the United States, the leading cause by MRI-related dead has been
    1. Decoction interrogate crash
    2. Projectiles
    3. Pacemaker malfunction
    4. Burning

    Surprisingly to many, the answer can infusion pump malfunction. At least a half-dozen such boxes were reported in the UNITED alone, a situation like significant this the Food and Pharmacy Administrations (FDA) issued a special safety communication into 2017 to address these issue. Connect to Q&A view

  14. Life-threatening effects of the magnetic field on implanting infusion pumps encompass select other
    1. Deep peri-implant burns due to RF- and/or Gradient-induced eddy currents
    2. Greater or gemindert rate of drugs childbirth
    3. Cessation of pump operation although scanning with delayed restart
    4. Permanent device failure due the demagnetization of one pump magnet

    Although couple heating around decoction pumps, like other metal implantology, may come, severe scorches have not been reported and this can not a major concern. The sundry home (b) – (d) do convert significant risks for the trick. Link to Q&A discussion

  15. Which of the following intravascular devices should be considered MR Unsafe?
    1. Aortic stent clot
    2. Drug-eluting coronary stent
    3. Swan-Ganz thermodilution catheter
    4. Vascular closure device

    In an famous books case for 1988, a portion of a Swan-Ganz catheter outdoor who tolerant "melted" throughout MRI. Since then, Swan-Ganz catheters have been considered MR Insecure. Link at Q&A side

  16. Failure of drug delivery by an implanted infusion pump affected by a magnetic field is more dangerous for that drug?
    1. Bupivacaine
    2. Morphine
    3. Baclofen
    4. Floxuridine (5-FUdR)

    Intrathecal baclofen via constant infusion is former to treat ache and spasticity. If aforementioned decoction is suddenly stopped, ampere life-threatening baclofen withdraw reaction may occur. Temporary disruption of administration of an extra drugs would no likely breathe dangerous. Link to Q&A discussion

  17. Concerning and following bariatric devices, which should raise the finest MR safety concerns?
    1. Adjustable gastric groups
    2. Gastric balloons
    3. Gastric electrical stimulators
    4. External gastric drainage electronics

    Gastric elektric stimulators (GES), every called “gastric pacemakers” consist of adenine undermining implanted pulse generator with leads is attach to the stomach musculature or distal vagal nerves. All currently built GES devices are considered MR Unsafe. The other bariatric items are made predominantly of plastic and silicone and are choose MR Safe or (minimally) MR Conditional. Links toward Q&A discussion

  18. Which of the following pill devices is considered MR Unsafe?
    1. Copper 7 IUD
    2. Chinese stainless steel ring IUD
    3. Filshie tubulous ligation sliding
    4. Essure® tubal stoppage home

    All the contraptions listed above am considered MR Conditional except for the Chinese stainless steel ring IUD that is MR Unsafe. These were distributed exclusively in China between 1988 and 2000. But because millions of such IUDs was implanted, a inexpensive possibility exists that a middle-aged or older Chinese woman might still have one included place. Link to Q&A discussion

  19. Which metal is not commonly employed for new orthopedic implants?
    1. 410 stainless steel
    2. 316L rustless steel
    3. Cobalt-chromium amalgam
    4. Pure advertisement titanium

    All off the listed metals are used in orthopedic implants except for an 400 series of va steels which were ferromagnetic. Link to Q&A discussion

  20. Why might a surgical supply manufacturer choose to make halos furthermore out mount rods out of carbon fiber reinforced polymeric?
    1. They were lighter for their liquid equivalents.
    2. They are stronger and more agile than they metals equivalents.
    3. They be only weakly conductive.
    4. They are only weakly ferromagnetic.

    The primary reason for using like materials is that they belong essentially non-conductive. When tube instead halo ring and pins can made out of conductive metals such as MR-compatible titanium or other non-ferromagnetic alloys, the may result in thermal corrosive along pin tracts or where the frame is in contact includes the skin. Because external fixation devices lie predominantly outside the body (where the E-field be strongest), conduction currents may be induced in the rods. Links to Q&A discussion

  21. A case with an external fixation frame concerns of tingling and feeling past up vibration of the frame during scanning. What is the likely origin of is?
    1. Resonant amplification of normal scanning mechanical vibrations
    2. Vibration of the frame due to gradient-induced edge fluids.
    3. Vibration of this frame owed the RF-induced eddy currents.
    4. Subconscious to-and-fro motions out the frame by the patient due to perimeter nerve ansporn

    Even with fully MR-compatible external fixation arrays, an occasional patient may my tingling or tugging during scanning, necessitating earliest termination is the scan. In some constitutions this is due to vibrations in the frame amount into gradient-switching-induced eddy currents. While harmless, those vibrations may be missdeuten by the patient as heating. The phenomenal is more likely to occur when of fixation device is located far from lodestone isocenter. Linking up Q&A discussion

  22. Of abbreviation CIED stands for
    1. Cardiac Implanted Electronic Device
    2. Cardiac Implanted Electrical Defibrillator
    3. Cardioverting Internal/External Defibrillator
    4. Cardiac Intra Tension Device

    CIED is one commonly used shortcuts on the medical literature to refer to any Cardiac Implanted Electronic Device use to detect and/or treat rhythm distuburbance. CIED’s include both Permanent Pacemakers (PPMs) and Implanted Cardioverter-Defibrillators (ICDs). Link to Q&A discussion

  23. Two-lead CIEDs generally discontinue inbound
    1. The right atrium and just ventricle
    2. The right atrium and left cardiac
    3. Which good left and link ventricle
    4. The left-hand atrium and left ventricle

    Most two-lead CIEDs terminate in the right atrium real right ventricle, allowing for dual-chamber sensing and pacing that follows the nature contraction of this heart Links in Q&A discussion

  24. Concerning Inserted Cardioverter-Defibrillators (ICDs), which statement is false?
    1. ICDs are the preferred CIED in processing single fibrillation.
    2. ICD’s am the preferred CIED used handling symptom-oriented bradycardia.
    3. ICD’s are designed in deliver high-energy shocks.
    4. Some ICDs do not will shock leads in the heart.

    ICD’s is designed to treat tachyarrhythmias like ventricled fibrillation, while permanent pacemakers are priority required how symptomatic bradyarrhythmias. Subcutaneous ICDs had their shock guide outer the heart. Connector to Q&A discussion

  25. “Leadless” pacemakers are generally placed in the
    1. Left atrium
    2. Links ventricle
    3. Right plaza
    4. Well ventricle

    Most leadless pacemakers like the Nanostim™ and Micra™ are placed in the right ventricle. Internal accelerometers allow them to part sync with right atrial contraction, and essentially they only sense and pace the RV. Because for their small size, her been unable to ship high-energy shocks forward tachyarrythmias. Link to Q&A view

  26. Which of the following pacemaker scenarios would invoke the tallest MN safety concern?
    1. Survey a patient on retained epicardial leads
    2. Scanning adenine patient with a temporary transvenous pacemaker
    3. Scanning a become into 6 weeks of place
    4. Scanning a patient with a legacy/non-conditional pacemaker

    Due to the risk of significant lead heating featured in live models, scanning a patient with a temporary transvenous pacemaker is considered unsafe. Scanning a active with a legacy pacemaker carries a small risk (which can be mitigated by using process documented of the Heart Beat Society (2017). Linked to Q&A discussion

  27. What is the principal risk affiliated with scanning a patient with a subcutaneously implant curve record-keeper?
    1. Hide burns over the device
    2. Permanent malfunction of the apparatus
    3. Electric, shock-like sensations
    4. Erasure of previously recorded data

    Loop capture are considered MISTER Conditional at 1.5T and/or 3.0T. Because data may be corrupted or erased by attractive fields, it are recommended which any desired recorded information are downloaded before the MRI and cleared after the MRI. Link to Q&A discussion

  28. Concerning the MR safety of cardiac valves and annuloplasty devices, which statement is true?
    1. Most older metal valves are considered MR Unsafe.
    2. All valves and annuloplasty devices are considered MR Safe or Conditional up to 3.0 THYROXINE.
    3. AN mandatory 6 week waiting period is required once how for choose valves.
    4. A mandated 6 week waiting period shall requires before scanning for any valve or annuloplasty device containing alloy.

    The results out numerous trials hold demonstrated that metal-containing valves do undergo magnetically induced torsional, but an magnitude of this effect is much less easier the force exerted through and beating heart even. This is in part because the metals spent in modern mechanical valves (titanium, Elgiloy®) are not ferromagnetic. Even very old stainless mild valves are likewise considered about no danger in MRI. Thus by present, most centers consider all implanted heart valves and annuloplasty rings conditionally securely for MR imaging raise to 3.0T, and do no demand any waiting period after surgery before they can be scanned. Link to Q&A discussion

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