MRI Safety Equipment Safety/Patient Safety Flashcards
The FDA recommends posting warning signs to indicate the _________ line.
5 Gauss
FDA safety levels for RF exposure during MR examination are defined by SAR restrictions, which are imposed to reduce the risk of:
Systemic and/or thermal injury to patient
FDA guidelines dictate a level of concern when RF energy absorption produces an increase in body temperature of:
1° Celsius
Risk factors of MR exposure with regards to SAR include all of the following EXCEPT:
Hypotension
What type of pulse sequence transmits the most RF to the patient and consequently can potentially have more SAR restrictions?
Fast spin echo
Fast spin echo sequences utilize ETL (echo train lengths/180° RF pulses) to reduce scan time, at the expense of increased RF power/absorption to the patient
The fringe magnetic field:
Can cause nearby medical devices to malfunction
Which of the following is regulated by the FDA?
Acoustic noise
RF energy is:
Low energy, non-ionizing radiation
ACR recommended Zone 1 signage designates an area intended for _________________.
General public
ACR recommended Zone 2 signage designates an area intended for:
Unscreened MRI patients
ACR recommended Zone 3 signage designates an area intended for:
Screened MRI patients/personnel
ACR recommended Zone 4 signage designates an area intended for:
Screened MRI patients under constant direct supervision of trained MR personnel
The magnetic field that the MR technologist is most exposed to would be the:
Static magnetic field
The intensity limit for a static magnetic field in clinical use is limited by the FDA to what field strength? (Clinical imaging in patients over one month of age and above)
8.0 Tesla
The intensity limit for a static magnetic field by the FDA for the entire population is?
4.0 Tesla
The pulse sequence that should be utilized the least in a patient with implanted metallic hardware is:
Gradient echo
Gradient echo sequences lack a 180° RF pulse that aids in correcting local magnetic field inhomogeneities, found in metallic implants.
A patient with a history of _______ should have their GFR checked prior to the administration of IV contrast.
All of the above
Kidney disease, hypertension, diabetes
Adequate patient care dictates a patient having an MRI should be __________ monitored
Visually and/or verbally
Patient types who may require additional monitoring while undergoing an MR exam might include:
All of the above
Claustro, Pediatric, unresponsive, limited vocal
The effect by which a patient may experience a visual stimulation, described as “seeing stars”, is known as:
Magnetophosphenes
When moving blood enters a magnetic field, an effect on the ECG seen as a “T wave swelling” or spike occurs, also known as:
Magnetohydrodynamic effect
Regions of the body that do not quickly dissipate thermal absorption from SAR during MR procedures are
Eyes and testicles
The following items are typically permitted access to enter a high field MRI system during an MRI guided core biopsy:
C and/or D
Aluminum interventional equipment, Sterile nonferrous biopsy tray
Prior to entering the MRI scan room, a patient should be screened for:
All of the above
Surgical implants, Pregnancy, Prior trauma or injury
During a quench, patients and employees should be evacuated from the scan room to prevent __________.
A and B
Ruptured tympanic membranes, Frostbite and asphyxiation
The primary biological effect of radiofrequency fields is ____________.
Tissue heating
As the flip angle is doubled, the RF absorption increases by a factor of __________.
4
The minimum acceptable method for detection of intra-ocular ferrous foreign bodies is:
X-ray
A more accurate method of detecting small intra-ocular ferrous foreign bodies is:
Cat Scan
The percentage of patients reported to have reactions to gadolinium MRI contrast are:
Less than 1%
It is ___________ that every patient having an MRI be provided auditory protection in the form ______________.
Recommended; earplugs and/or headphones
The general public is limited to a magnetic field of ___________?
5 Gauss
The FDA limit on time varying magnetic fields is __________.
Once the patient experiences peripheral nerve stimulation
Cables from RF coils and gating leads should be:
Braided and positioned straight in the bore
RF heating is more of a concern in ________ sequences.
Fast spin echo
When would sterile technique be utilized?
When performing any procedure that would puncture a patient’s skin
Risk factors of MR exposure with regards to SAR absorption include all of the following EXCEPT:
Hypotension
The fringe magnetic field:
Specific absorption rate
FDA limits for whole body SAR is ______ over 15 minutes of scanning.
4 W/kg
FDA limits for whole body SAR is 4 W/kg over 15 minutes of scanning
