Anatomical Sequences The anatomical scans will be done at the McCausland Center for Brain Imaging located near the Radiology Department in the Palmetto-Richland Medical Center, which is the teaching hospital for the University of South Carolina School of Medicine. This center has a Siemens 3T “TIM Trio” MRI. The motivation is to acquire safe, rapid, high quality anatomical scans to allow the EEG/ERP data / EGI Sensor net electrodes to be accurately co-registered and dipole source calculations to be solved. High resolution 3D T1-weighted scans are typically used to produce suitable anatomical scans of adult brains (e.g., 3D Magnetization Prepared Rapid Acquisition with Gradient Echoes, MPRAGE). However, there is evidence that T1-weighted images alone will not be sufficient to segment white and gray matter in infant brains reliably [Gilmore, Zhai, Wilber, Smith, Lin, Gerig, 2004][Williams, Gelman, Picot, Lee, Ewing, Han, Thompson 2005]. In neonatal brains, it has been reported that T2-weighted scans may be preferable for white/gray segmentation [Williams, Gelman, Picot, Lee, Ewing, Han, Thompson 2005]. Therefore, a dual-echo Turbo Spin Echo (TSE) acquisition also will be performed, which will provide a proton density (PD) and T2-weighted image for each slice position. This also has the advantage of conforming to the NIH MRI study of normal brain development [NIH 1998][Evans 2006][Almli, Rivkin, McKinstry, submitted][NIHMRI 2004]. By combining the T2-weighted scan with the PD image, a crude T2 map can be constructed. This should be advantageous for segmentation as the majority of signal non-uniformity throughout the RF coil is removed in the T2 calculation. Furthermore, the acquisition parameters must be modified to take account of both the differences in contrast between adult and infant brains, and the use of a 3T scanner [Rutherford, Malamateniou, Zeka, Counsell 2004]. It has been reported that T1 values in infant brain increase by around 1000 ms when moving from 1.5T to 3T whereas T2 values remain fairly consistent between field strengths [Williams, Gelman, Picot, Lee, Ewing, Han, Thompson 2005]. This has been reflected in the acquisition parameters for the T1 weighted MPRAGE scan used by increasing both the inversion time (TI) and repetition time (TR) between inversion pulses.
The extra signal available from a 3T MR scanner may be utilized to obtain improved spatial resolution or a quicker scan. In this case, the emphasis is on reducing scan time to increase the number of subjects scanned successfully without head movement or before waking in the scanner. This scanner is equipped with a 12-channel parallel imaging head coil, allowing the application of parallel imaging techniques to further speed up the acquisition. The use of parallel imaging also offers benefits in slightly reducing the acoustic noise of the scanner, as the reduced number of echoes in a TSE sequence, resulting from use of parallel imaging, allows more time to ramp the gradients more slowly, thereby reducing acoustic noise (so-called “whisper” sequences). Although a smaller knee RF coil is available which historically has been used to scan infants’ heads, it does not support parallel imaging, and initial experiments suggest its use would not be beneficial in terms of image quality compared to the 12 channel head coil. The use of parallel imaging reduces the number of RF pulses applied to the subject (by reducing the echo train length) and thus reduces the amount of RF energy the subject receives (reduction in SAR, see Human Subjects Protection section).
The scanning protocol will be as follows: A localizer sequence (45 seconds) will first be done to orient the subsequent high resolution slices so that the longitudinal fissure is parallel with the saggital plane, perpendicular to both coronal and axial planes, and the AC-PC line is on the center MRI slice. This will orient the scan so that the MRI may be oriented relative to the AC-PC line for Talairach space [Talairach, Tournoux 1988]. This will be followed by the 3D MPRAGE T1-weighted scan, acquired sagittally to allow whole head coverage with the fewest number of slices. The MPRAGE employs a TI of 960 ms, a delay of 3000 ms between shots and an 8 degree flip angle, with a very short TE (4.9 ms) and a parallel imaging reduction factor of 2, and whisper mode. Using this sequence we can collect a 1mm isotropic (256x256x128 mm FOV) in less than 5 min. This scan will be repeated if degraded by motion artifacts. The gray matter, white matter, and CSF can be segmented from the T1W scan, but a subsequent T2W scan helps to discriminate white matter and CSF with automatic segmenting routines. This is acquired as a dual contrast proton density and T2-weighted sequence with a dual echo fast spin echo sequence. The dual echo acquisition takes under 5 minutes to acquire (256x256 matrix with rectangular FOV, 1x1mm pixel size, 2mm slice thickness, no slice gap, 50 saggital slices in two interleaved packages, echo train length of 10, first TE=13ms, second TE=101ms, TR=4640ms, parallel imaging factor=2). If there are large motion artifacts in the T2W scan, it also will be repeated. If only the T1W scan is available, some automatic classification / segmentation routines will be substituted with manual segmentation routines of the T1W scan. The MRI scans will be identified only with a participant number to protect participant confidentiality. The MRI images are transformed into DICOM images which are passed from the Center for Brain Imaging to the PI computer server over a network line secured with VPN connection.
MRI Procedure The informed consent procedure is done at the University of South Carolina laboratory, including the screening for parents to be in the scanner room. The infant’s height will be measured and the infant will be weighed to obtain values for input to the Siemens scanner software. The method for doing the MRI recording will follow that used by several laboratories for doing MRIs of non-sedated infants [Paterson, Badridze, Flax, Liu, Benasich 2004][Dehaene-Lambertz, Dehaene, Hertz-Pannier 2002][Gilmore, Zhai, Wilber, Smith, Lin, Gerig 2004][Evans 2006][Almli, Rivkin, McKinstry, submitted][NIHMRI 2004]. Parents and infants are invited to the McCausland Center for Brain Imaging at a time when the infant is regularly scheduled for sleep—such as early evening, or late afternoon naps. Parents are instructed to keep the infant awake as long as possible before the session and to plan a feeding (nursing, or bottle) immediately prior to the scan. Upon arrival to the imaging center the infant and parent are checked for magnetic items before entering the scanner room. Then the infant will be prepared for the scan. This includes swaddling in a light cloth blanket. The parents then will use a rocking chair, soothing music, or other customary bedtime routines. As the infant begins sleeping, the infant will be given infant-earplugs, acoustic foam pads over the ears, earphones, and a flexible foam covering or custom designed Styrofoam bead bag that fits snugly around the head and ear covering and will keep the ear coverings in place. The covering also keeps the infants head still in the MRI coil. When the infant is sleeping, the parent will lay the infant on the scanning table and the imaging procedure can begin. The parent may choose to be in the scanner room with the infant. In that case, the parent is checked for magnetic items, uses earplugs and headphones, and will sit in a chair in the MRI scanner room. Success rates for scanning young infants without sedation range from 66% [Gilmore, Zhai, Wilber, Smith, Lin, Gerig 2004], 75% [Sury, Harker, Begent, Chong 2005] to 90% [Evans 2006][Almli, Rivkin, McKinstry, submitted] and scan failures are most often due to not being able to get the child to sleep [Almli, Rivkin, McKinstry, submitted][Gilmore, Zhai, Wilber, Smith, Lin, Gerig 2004] or the child waking during the scan [Almli, Rivkin, McKinstry, submitted]. The infants will be monitored with the Siemens pulse oximetry system integrated into the Siemens “Tim Trio” scanner to check for pulse or oxygen changes during the scanning.
The risks associated with the MRI recording in pediatric infant populations are minimal. An extended discussion of these risks will be presented, but the conclusion is that these risks have been minimized to an acceptable level for infants participating in scientific research. There are now several basic scientific research studies of MRI recording in non-sedated infants at 1.5T [Dehaene-Lambertz, Dehaene, Hertz-Pannier 2002][Evans 2006] and 3.0T [Gilmore, Zhai, Wilber, Smith, Lin, Gerig 2004][Rutherford, Malamateniou, Zeka, Counsell 2004], with much of that work being supported by the National Institutes of Health (e.g., MRI study of normal brain development [Evans 2006], Early brain development in twins (R01MY070890 [Gilmore 2005]), Early brain development in high risk children (P50MH064065 [Gilmore#2006]).
The US FDA lists four potential risks for the MRI: main static magnetic field, specific absorption rate (SAR), gradient fields rate of change, and sound pressure level [USFDA 2003]. In addition to these four, the presence of ferromagnetic materials in the scanner room poses a risk. The U.S. FDA considers MRI recording in infants to be a “non-significant” risk when used within FDA specified parameters [USFDA 2003][USFDA 2006]. This assessment is based on over 20 years of MRI recording in neonate and infants (e.g. [Barkovich, Kjos, Jackson, Norman 1988][Rivkin 2000]) with no reports of deleterious long-term effects, and on several studies showing no short-term or long-term effects from this type of recording [Schenck 2000][Kangarlu, Burgess, Zu 1999][Baker, Johnson, Harvey, Gowland, Mansfield 1994][Kok, de Vries, Heerschap, van den Berg, 2004][Clements, Duncan, Fielding, Gowland, Johnson,Baker, 2000][Myers, Duncan, Gowland, Johnson, Baker 1998]. These risks are discussed in detail in several sources [Stokowski 2005][Barkovich 2005][Dehaene-Lambertz 2001][Evans 2006][ACR 2002][ACR 2004] and the major points of those sources are reviewed here.
The first risk is the static magnetic field [Schenck 2000]. The FDA deems static magnetic fields up to 8.0T are a non-significant risk to infants aged greater than 1.0 months. Studies of the effects of static magnetic fields on humans in field up to 8.0T indicate that there is a substantial margin of safety for the 3.0T MRI to be used in the proposed project [Schenck 2000]. MRI scanning of normal neonates and infants is routinely done with magnetic fields at this 3.0 T level [Gilmore, Zhai, Wilber, Smith, Lin, Gerig 2004][Rutherford, Malamateniou, Zeka, Counsell 2004].
The second risk is the RF electromagnetic effects caused by electromagnetic coils and a transmitter that delivers RF pulses during the imaging [Shellock 2000]. This the greatest of the four risks associated with the MRI process. The RF pulses may cause tissue heating, heating of implanted electrical devices, or heating of implanted metal. The RF “Specific Absorption Rate” (SAR) is the amount of energy per second absorbed per kilogram of body mass (Watts per kg, W/kg) from application of the RF pulses required by the MR acquisition. The US FDA sets the limits for SAR in MRIs. There are four maximum allowable SAR measures: 3 W/kg averaged over the whole head in 10 min, 4 W/kg averaged over the whole body in 15 min, or 8 W/kg per gram of head/torso tissue in 5 min or 12 W/kg per gram of extremity tissue over 5 min [USFDA 2003]. The SAR level is a major concern when performing MRI of infants, especially at 3T. Compared to 1.5T, at 3T, more energy is required in order to flip the precessing protons by the same flip angle. Due to infants’ small mass, the fact a larger proportion of body mass is in the RF coil, and concern that any potential interactions may have a larger effect while the body is developing rapidly, then special effort should be made to control the SAR of sequences. There are a number of sequence optimizations which may be performed at 3T which mitigate the theoretical quadrupling of SAR compared to 1.5T (see Anatomical Sequences in “Realistic cortical source models of infant ERP using infant MRI” section). The use of the increase in signal at 3T to apply parallel imaging techniques successfully decreases acquisition time and reduces the number of RF pulses applied, by roughly the parallel imaging factor in the case of the spin echo and single gradient echo sequences to be used for this study. The longer T1s at 3T require lower flip angles or longer TRs to maintain optimal T1 contrast, which results in a slight lowering of SAR. The T1W scan we will use is a 3D MPRAGE T1-weighted scan, with a TI of 960 ms, a delay of 3000 ms between shots and a 8 degree flip angle, with a very short TE (4.9 ms) and a parallel imaging reduction factor of 2, and whisper mode. A T1W sequence on the Siemens software was tested with these values, and the height and weight for an infant the size of the youngest / smallest in this study were entered into the software. The Siemens software estimated this will produce SAR levels of less than 0.44 W/kg for the whole head exposure for an infant of this size, significantly less than the FDA limits. The SAR can be further lowered in the TSE sequence by reducing the 180 degree focusing RF pulses by application of the hyperecho technique [Hennig, Scheffler 2001], available on the Siemens platform. The T2W scan we will use is acquired as a dual contrast proton density and T2W sequence with a dual echo fast spin echo sequence, with an echo train length of 10, first TE=13ms, second TE=101ms, TR=4640ms, parallel imaging factor=2. The Siemens software estimates this will produce SAR levels of about 1.32 W/kg for the whole head exposure, well below the FDA limits. Though these optimizations may be unlikely to reduce SAR to typical levels seen on 1.5T scanners, we and other groups [Gilmore, Zhai, Wilber, Smith, Lin, Gerig 2004][Rutherford, Malamateniou, Zeka, Counsell 2004] believe that the described reduction in SAR achievable at 3T, combined with the rapid scan times and improvement of image quality, justify the use of a 3T MR scanner for this study.
The magnetic gradients are the third FDA risk [Schaefer, Bourland, Nyenhuis 2000]. The magnetic gradients are time-varying magnetic fields (dB/dt) induced along the static magnetic field and induce electrical field changes in nuclei with magnetic moments. The magnetic gradients may induce circulating electrical currents in the conductive tissues of the body, producing change in nerve and muscle function, resulting in nerve stimulation, which potentially causes discomfort or painful nerve stimulation. The magnetic gradient effects are controlled by limiting the maximum rate of change in the magnetic gradients. The US FDA MRI standards state that significant risk will be “Any time rate of change of gradient fields (dB/dt) sufficient to produce severe discomfort or painful nerve stimulation” [USFDA 2003] but do not give a specific dB/dt limit. A suggested upper limit for non-significant risk are dB/dt of 20 T/sec [Schaefer, Bourland, Nyenhuis 2000]. The Siemens software uses a “SAFE Model” (Stimulation Approximation by Filtering and Evaluation) for the stimulation limits that takes into account the dB/dt, and the relation between the stimulation effect and the parameters of the measurement sequence (rise time, amplitude,number of axes, repetition rate, etc.) The stimulation limits are determined by empirical procedures using clinical trials, and at the threshold level could result in nerve stimulation in nor more than 1% of individuals. The Siemens software estimates the T1W and PD/T2W scans to be used in the current proposal will produce stimulation levels of about 21% of its stimulation level threshold, well below suggested upper dB/dt limit of 20 T/sec. Outcome studies of such effects show that the magnetic field or the magnetic gradients do not threaten the concurrent physiological stability of the infant during scanning [Battin, Maalouf, Counsell, Herlihy, Hall 1998][Taber, Hayman, Northrup, Maturi 1998][Stokowski 2005]. The infants will be monitored with the Siemens pulse oximetry system integrated into the Siemens “Tim Trio” scanner to determine if any physiological stability changes occur during the scan.
The fourth risk is the acoustic noise. The US FDA limit for sound is140 dB (SPL, unweighted) or 99 dB (A) with hearing protection in place [USFDA 2003]. The main source of noise is the generation of the magnetic gradient, which is about 100 dBA SPL for the Siemens Trio scanner. The magnet tunnel has internal acoustic insulation for noise protection which reduces noise and vibrations in the tunnel (~ -10 dbA). The sound level is reduced for the infant by placing sponge foam or wax ear plugs in the external ear canals, a foam pad over the ears, and head phones or ear muffs (e.g., Avotec, Inc., Jensen Beach, FL) over the ears. The infants head will then be covered with a flexible foam covering or custom designed Styrofoam bead bag that fits snugly around the head and ear covering and will keep the ear coverings in place. The outer covering also stabilizes the infants head in the MRI coil. This procedure should attenuate the acoustic noise by about -30 dBA, leading to sound levels of about 70 dBA (SPL) for the infant participant. Other personnel in the scanning room during scanning will have sponge foam or wax ear plugs and headphones, which decreases the sound level to about 70 dBA (SPL) during the scanning.
The fifth risk is from external ferromagnetic materials. These include biomedical implanted electrical devices (e.g., heart pacemaker, defibrillator, neurostimulator) or implanted metal (e.g., aneurysm clips, skull plate, metal pins, dental brace, bullet or bullet fragments, metal slivers, non-removable piercing), external ferromagnetic material brought into the room by the participant or parent (belts, shoes, diaper pins), and other ferromagnetic material in the scanner room. There are two risks to such ferromagnetic materials. First, the RF effects may cause heating of other materials, i.e., ferromagnetic or metal implanted materials, monitor cables or wires used for physiological monitoring, heating of diaper pins, or other materials in the scanner. Magnetic materials internal to the patient may undergo severe heating in the high magnetic fields and from the RF electromagnetic effects. Second, the ferromagnetic materials may cause projectile missiles in the static magnetic field. The procedures to minimize risk from ferromagnetic materials include the following: 1) an IRB-approved form is given to the parents during the informed consent process that inquires about contraindications for MRI recording. These include implanted ferromagnetic metal or electrical devices (infant or parent), medication patches, and IUD birth control. No infants will be scanned with any implanted devices. Any implanted devices or ferromagnetic material in the infant will be contraindications for inclusion in the study. No parent will be allowed in the scanning room with any implanted medical devices, or any implanted ferromagnetic metal. No mother will be allowed into the scanning room if pregnant. Any questionable implanted material in the parent will be a contraindication for being allowed in the scanning room. 2) the parent(s) are again questioned about contraindicating conditions for infant or parent immediately prior to the scan to confirm the questionnaire screening; 3) the parent and the infant are screened for metallic objects prior to entering the scanning room. The infants are undressed to check for clips, diaper pins, or other metallic object in their clothes or on their body (e.g., earrings). The parents are led through a “head to toe” examination for potential metallic objects, including hearing aids, glasses with metal frames, hairpins, earrings, jewelry, watch, shoes, wallets (credit cards), cell phone, and so forth. A similar examination for metallic objects is done for anyone entering the scanning room. 4) No other metallic objects are allowed in the scanning room at any time. Some devices are allowed in the scanning room that are MR-safe. MR safe items are those that pose no known hazards in the MRI environment [Shellock 2006]. Some equipment or material are MR-safe and will be allowed if the make and model of the device is known and these have been verified as being safe for a 3.0T scanner. Shellock [Shellock 2006] and the American Society for Testing and Materials International [ASTM 2005] are references to the MR-safe devices.
Another potential risk is sedation; infant movement causes artifact or distortion in the MRI images and often infants are sedated during MRI studies. However, sedation will NOT be used in this work so this is not a risk for infant participants. Several laboratories do MRI recording with normal infants who are non-sedated [Gilmore, Zhai, Wilber, Smith, Lin, Gerig 2004][Evans 2006][Paterson, Badridze, Flax, Liu, Benasich 2004][Dehaene-Lambertz, Dehaene, Hertz-Pannier 2002]. The increased SNR afforded by imaging at 3 T can be used to obtain information in a shorter time. The procedures for doing such work involved recording the infant at a time that is regularly scheduled for sleep, feeding the infant immediately prior to the scan, swaddling the infant during the scan, and restricting head movement with a foam or Styrofoam bead bag head covering. In all of this we will follow the protocol developed by the NIH MRI study of normal brain development [NIH 1998][Evans 2006][Almli, Rivkin, McKinstry, submitted][NIHMRI 2004]. The general outlines of this procedure may be found in the current proposal (Experiment Design and Methods, MRI Procedure). These methods should not increase the risk to the participant.
2. Adequacy of Protection Against Risks
a. Recruitment and Informed Consent
For the anatomical MRI recording, the informed consent consists of a description of the MRI recording situation, a questionnaire about contraindicating conditions (primarily magnetic implants), and a debriefing form describing the risks and benefits of the MRI recording. There is an infant participant and a parent participant questionnaire about contraindicating conditions (e.g., magnetic implants) because parents will be going in and out of the scanning room and may choose to stay in the room with the infant during the scan. The Institutional Review Board for the Use of Human Subjects in Research at the University of South Carolina the MRI recording, and approval is pending for these studies. This IRB includes as members a developmental psychologist, several physicians including one from pediatrics and a pediatric neurologist, community members, and several other scientists.
b. Protection Against Risk
The risks for the MRI recording have been outlined earlier (section 1C) and steps to protect these risks also have been detailed. These will be briefly summarized here. The risks associated with the MRI are minimal. The static magnetic field of the 3.0T MRI is considered a non-significant risk by the US FDA. The magnetic gradients of the scanner are controlled by the Siemens scanner system and have conservative pre-set safety limits. The RF electromagnetic effects have their risks limited by choosing sequences that are designed to meet US FDA guidelines. The height and weight of each participant is taken during the informed consent process and entered into the Siemens software before scanning. The height and weight variables entered into the Siemens software and the variables of the scanning sequence are used to calculate the estimated SAR, and the resulting SAR levels are limited to minimal levels. Acoustic noise hazard is protected against with the use of infant earplugs and headphones for the infant and earplugs/headphones for parents in the scanning room. The effects of ferromagnetic materials are minimized with parental screening for contra-indications for scanning, pre-scan examination of the infant and parent for ferromagnetic materials, and correct procedure for scanning staff entering the scanning room. The infants will be monitored with the Siemens pulse oximetry system integrated into the Siemens “Tim Trio” scanner to check for pulse or oxygen changes during the scanning. The protections for risk and the characteristics of the proposed study will be approved by the Institutional Review Board for the Use of Human Participants in Research at the University of South Carolina.
Special training will be done for the research assistant, pediatric radiology nurse, and PI in the conduct of MRI research in normal infants without sedation. The MRI recording will use the protocol established for the NIH MRI study of normal brain development [NIH 1998][Evans 2006][Almli, Rivkin, McKinstry, submitted][NIHMRI 2004]. This was a multi-center research project sponsored by the National Institutes of Health that did 1.5T anatomical MRIs for infants in this age range. Dr. Robert Almli in the School of Medicine at Washington University in St. Louis was one of the sites that has recorded the MRIs for infants in the age range of the current project. Dr. Almli has consented to allow the research assistant and pediatric radiology nurse to observe / participate in the recording of infants in his laboratory and will provide training to these personnel in the protocol. These two people will travel to St. Louis for this training in advance of any MRI recording that is done on the current project. The PI also will visit the Washington University laboratory to observe the procedure and to obtain details for the conduct of this work.
Several people are involved in this project that aid in the protection against risks. First, one consultant is a MRI physicist, Dr. Paul Morgan, who designs the MRI sequences, evaluates the fidelity of the anatomical MRIs, and consults on the recordings throughout the course of the project (Biosketch, Letters of Support). Second, a consultant is Dr. William Savoca of Pitts Radiology Associates (Biosketch). The Pitts Radiology Associates is the contracting radiology physician group practice for the MRI facilities of the Palmetto-Richland Hospital. Dr. Savoca will assess all MR scans for clinical abnormalities. Any clinically abnormal recordings will be reported to the PI who will notify the parents and with their permission will forward the results to the child’s primary care physician as designated by the parents. A letter of agreement is included from Pitts Radiology Associates concerning this arrangement. Third, several people will be present during the scanning who have medical and MRI safety training. These include a pediatric radiology nurse, a research assistant with MRI technology safety certification, and the PI. The pediatric radiology nurse will come from the pediatric unit of the Department of Radiology Services at the Palmetto-Richland hospital. The pediatric division does about 65 MRIs per year on infants in this age range and have several experienced nurses available for this work. All nurses in the Radiology department are BCLS, ACLS, and PALS certified, and have completed a course in critical care. The parent will accompany the infant in the scanning room to put the infant in the scanner and may remain in the scanning room if they wish. The parent may stop participation in the experiment at any time. The PI and research assistant doing the MRI recording have been trained and certified for safety by the Safety Committee of the Center for Brain Imaging.
The Siemens “Trio” system has three emergency shutdown procedures. The first is computer-controlled and is for relatively minor situations. This shutdown will immediately terminate the MRI scanning and the bed may be removed from the magnet core in under 5 s. This could be done if the infant or parent is showing signs of distress or if the parent wants to immediately end participation in the experiment. The second and third shutdowns are rarely used. The second shutdown is for situations involving the scanner. This shuts down the ongoing scan and turns off all computer systems attached to the scanner. This is done with a manual switch. One switch is located in the scanning room and one is in the control room. The bed may be removed from the scanner electronically at the side of the bed or in a manual mode. The infant may be evacuated from the magnet core in less than 5 s. The third shutdown is an emergency “quench” shutdown of the system. This can be made with an emergency switch in the scanning room or one in the control room. This shuts down the total system, removes the cryogens that keep the magnet cooled and in a superconducting state, and decreases the static magnetic field. This is done in extreme circumstances, such as if someone has been pinned to the magnet with a ferromagnetic projectile. In the case of a quench the infant, parent, and all personnel are evacuated from the MRI suite due to the possibility of the presence of the cryogens in the scanning room.
Medical emergencies in the MRI suite will be handled by the pediatric radiology nurse and hospital staff. The nurses are BCLS (CPR), ACLS (Advanced Cardiac Life Support), and PALS (Pediatric Advanced Life Support) certified, and have completed a course in critical care. The infant may be removed from the scanner in approximately 5 s if an emergency is detected. If an infant requires any more than minor attention during the examination it will be brought out of the scanning room for these procedures. The pediatric radiology nurse may decide the infant or parent needs more than routine attention. The MRI suite has a hospital code alarm which will summon emergency personnel from the Palmetto Richland Hospital. In the event of adverse effect to the participant during the MRI scanning personnel will be available for emergency treatment in accordance with the hospital standards for human subjects’ protection.
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