Risks/ Discomforts/ Inconveniences
The long-term effects of MRI procedures on the body are unknown. However, there is no evidence of harmful or adverse effects.
The Food and Drug Administration (FDA) has set recommendations for exposure in MRI studies and this study satisfies those criteria. However, there are unique considerations associated with MR imaging, which we will address below. We will screen every participant for contraindications (e.g., metal in the body, head or brain) prior to scanning to ensure that it is safe for them to enter the scanner. This screening will include a personal interview with a standard MRI safety screening form. The MRI safety screening asks individuals to report about the presence of non-removable metal in or on the body, implanted medical devices, tattoos, medication patches, orthodontia (braces or permanent retainers), hearing aids, eyeglasses (corrected vision is acceptable so long as participants can wear contact lenses or MRI-compatible glasses), previous MRI history, history of claustrophobia or breathing disorders, and current medications. This screening is important to ensure that participants are safe for MRI scanning.
On the day of the scan, screening procedures will take place as follows:
1. MRI screening: On the day of the MRI scan, we will repeat the MRI safety screening to verify the participant’s safety in the MRI environment on that day.
2. Urine pregnancy screen. We will administer a urine pregnancy test for all people of childbearing ability to verify the absence of pregnancy on the day of MRI scanning. If there is a positive result, the participant will be excluded from the study, and the results will be disclosed the participant.
Day of scan procedures for maintaining participant safety and comfort:
1. MRI setup: In the MR scanner, we can communicate with the participant via a microphone and camera. The participant can receive instructions and check in between scanning runs.
2. Ability to terminate MRI scan: Participants will be removed from the scanner anytime they request to end the scan. They can communicate their desire to exit the scanner by speaking with experimenters at any time, or by squeezing a ball device (in the participant’s left hand) while the scanner is running.
3. Participant monitoring: We will monitor the participants through the window at the MRI scanner to ensure that there are no overt signs of discomfort. Excessive participant movement may indicate discomfort. When this is observed, the staff will speak to the participant and ask about their comfort.
Procedures for minimizing risks
Specific risks associated with study participation:
1. Claustrophobia. The MRI procedure is painless and noninvasive. It does require the participant to lie still, with the head and part of the body in a tunnel-like device. Approximately 3% of participants cannot tolerate the procedure because of claustrophobia.
2. Acoustic noise. Some participants find the loud sounds of the oscillating gradients during image acquisition to be discomforting.
3. Heating. The guidelines from the Bureau of Radiological Health by the FDA will be followed in regard to specific absorption rate (SAR) of radiofrequency energy and time varying magnetic fields (dB/dt).
4. Incidental MRI finding. Structural and functional images of the brain will be collected during the MRI scan, raising the possibility of detecting a brain abnormality not otherwise known to the participant.
Procedures for addressing specific potential risks outlined above
1. Claustrophobia: If any participant experiences claustrophobia they may terminate the study immediately. Additionally, we will pre-screen for claustrophobia to reduce the risk that participants will find the enclosed space intolerable.
2. Acoustic noise: The noise created by the scanner is below FDA guidelines of 140 dB peak referenced to 20 micropascals. Because of the loud noise generated by the imaging, all participants will be supplied with 30db attenuating foam earplugs and headphones. In addition, padding will be used to fill in spaces between the participant’s head and the head coil. This serves three purposes. First, it aids in noise abatement. Second, it helps participants remain still. Third, the foam reduces participant discomfort. Any request to terminate the study because of noise will be accommodated immediately.
3. Heating. As indicated above, we will follow guidelines from the Bureau of Radiological Health by the FDA in regard to specific absorption rate (SAR) of radiofrequency energy and time varying magnetic fields (dB/ dt). Precautions will be maintained so that SAR will be less than 8watts/kg in any 1 gram of tissue. This is the estimated power required to raise the temperature 1 degree centigrade. The maximum dB/dt will be set at 20T/sec for > 120us or 200T/sec for < 12usec. These levels are well below peripheral nerve stimulation threshold in both children and adults.
4. Procedure in the event of an incidental MRI finding: A radiologist reviews all anatomical scans conducted in this study, within a month of the scan date, whether or not an anatomical abnormality is suspected. In the event of an incidental finding requiring follow-up, the radiologist will immediately alert the PI, and will provide them with information describing the abnormality. The PI or a delegated person will call the participant. They will discuss the finding with the participant and may recommend that the participant arrange for a diagnostic MRI. Medical expenses will not be reimbursed by study personnel but will be billed to the participant’s insurance company. There is a minimal risk of undue stress or concern and costs for treatment, if referred to the participant’s insurance company. In addition, it is possible that participants could be unnecessarily worried if a problem were suspected, but not actually found. All participants are made aware of this concern prior to scanning. If at any time during discussions a participant experiences significant psychological or emotional distress, they will be referred for evaluation and psychological counseling.