Personnel Qualifications
Interpreting Physician Personnel Qualifications [1]
Must meet country’s qualification requirements
Must meet one of the following Continuing Experience requirements:
Currently meets the Maintenance of Certification (MOC) requirements for the ABR or the Osteopathic Continuous Certification (OCC) for AOBR.
Physicians reading MR examinations across multiple organ systems must have interpreted 200 MR exams over the prior 36 months.
Physicians reading organ-system-specific exams (i.e. body, abdominal, musculoskeletal, head) across multiple modalities must interpret a minimum of 60 organ-system-specific MR exams in 36 months; however, they must interpret a total of 200 cross-sectional imaging (MRI, CT, PET/CT and ultrasound) studies over the prior 36 months (the 60 organ-system-specific exams are included in the 200 cross-sectional imaging studies).
Cardiac MR Continuing Experience requirements [2]
Radiologists reading Cardiac MR examinations must have read 50 exams over the prior 24-month period. The cardiac exams interpreted will count toward the overall continuing experience for other MR modules.
Cardiologists reading Cardiac MR examinations must have continuing experience in accordance with level 2 requirements or higher - 50 examinations each year.
Breast MR Continuing Experience requirements [2]- Meet one of the following:
Meets Maintenance of Certification (MOC) requirements for ABR or the Osteopathic Continuous Certification (OCC) for AOBR
75 breast MRI exams in the prior 36 months
Must meet one of the following Continuing Education requirements:
Currently meets the Maintenance of Certification (MOC) requirements for the ABR or the Osteopathic Continuous Certification (OCC) for AOBR.
150 hours CME (including 75 hours category 1) in the prior 36 months pertinent to the physician's practice patterns (see the ACR Practice Parameter for Continuing Medical Education).
15 hours CME (half must be category 1) in prior 36 months specific to the imagingm modality or organ system
Cardiac MR Continuing Education requirements:
Radiologists interpreting MR Cardiac must have earned at least 15 CME hours in MR (half of which must be category 1) in the prior 36-month period and should include CME in Cardiac MR as is appropriate to the physician's practice needs.
Cardiologists interpreting MR Cardiac must have completed at least 30 hours of coursework in the prior 36-month period, in accordance with Level 2 requirements.
Breast MR Continuing Education requirements- Meet one of the following:
Meets MOC requirements for ABR or the OCC for AOBR
150 hours CME (including 75 Cat 1) in the prior 36 months pertinent to the physician’s practice patterns
15 hours CME (half of which must be Cat 1) in the prior 36 months specific to the imaging modality or organ system (CME may be in MRI, breast, or a combination)
The requirements specify that physicians must complete 15 hours of continuing education(half in category 1) in the prior 36 months specific to the imaging modality or organ system. These CE credits may be in MRI, breast, or a combination of MRI and breast. As examples, the following would meet the continuing education requirements for the Breast MRI Accreditation Program:
15 hours of CE in MRI of any body part (e.g. brain, musculoskeletal or breast): this is acceptable because MRI is the imaging modality
15 hours of CE in breast ultrasound: this is acceptable because the breast is the organ system
15 hours of CE in mammography: this is acceptable because the breast is the organ system
15 hours of CE in breast MRI: this is acceptable because it meets both the organ system condition and the modality condition
In addition, the physician shall have the responsibility for all aspects of the study including, but not limited to, reviewing all indications for the examination, specifying the pulse sequences to be performed, specifying the use and dosage of contrast agents, interpreting images, generating official interpretations (final reports), and assuring the quality of both the images and interpretations. The physician interpreting breast MRIs must have knowledge and expertise in breast disease and breast imaging diagnosis.
Medical Physicist Personnel Qualifications
Must meet country qualification requirements
Must perform 2 MR unit surveys within 24 months
Must meet one of the following Continuing Education requirements:
Currently meets ABR Maintenance of Certification requirements for medical physics or
ABMP MOC requirements.
For both MRI and Breast MRI: Completes 15 CEU/CME (1/2 Cat 1) in the prior 36 months (must include credits pertinent to the accredited modality)
The medical physicist/MR scientist must:
Be familiar with the principles of MRI safety for patients, personnel, and the public; the Food and Drug Administration’s guidance for MR diagnostic devices; and other regulations pertaining to the performance of the equipment being monitored.
Be knowledgeable in the field of nuclear MR physics and familiar with MRI technology, including function, clinical uses, and performance specifications of MRI equipment, as well as calibration processes and limitations of the performance testing hardware, procedures, and algorithms.
Have a working understanding of clinical imaging protocols and methods of their optimization. This proficiency should be maintained by participation in continuing education programs of sufficient frequency to ensure familiarity with current concepts, equipment, and procedures.
Be responsible for the conduct of all surveys of the MRI/Breast MRI equipment. The medical physicist/MR scientist may be assisted by properly trained individuals in obtaining data in accordance with applicable regulations. The medical physicist (or MR Scientist for MRI recognition) is responsible for determining if the assisting individual is “properly trained.” These individuals must be approved by the medical physicist/MR scientist in the techniques of performing tests, the function and limitations of the imaging equipment and test instruments, the reasons for the tests, and the importance of the test results. Any assisting individual must be under the direct supervision of the medical physicist during the surveys (direct supervision means that the medical physicist/MR scientist must be present in the facility and immediately available to furnish assistance and direction throughout the performance of the procedure; direct supervision does not require that the medical physicist be present in the room when the procedure is being performed; teleconferencing does not constitute direct supervision).
Be present during the surveys; review, interpret, and approve all data; and provide a report of the conclusions with his/her signature.
Technologist Personnel Qualifications
Must meet country's qualification requirements.
Must have 24 hours of continuing education every 2 years.
CE must be relevant to imaging and the radiologic sciences, patient care.
CT must include credits pertinent to technologist's clinical practice.
MRI Equipment Quality Control (QC)
The MR equipment specifications and performance shall meet all state and federal requirements. The requirements include, but are not limited to, specifications of:
Maximum static magnetic field strength
Maximum rate of change of magnetic field strength (dB/dt)
Maximum radiofrequency power deposition (specific absorption rate)
Maximum auditory noise levels
A quality control (QC) program must be established and implemented under the supervision of a qualified medical physicist (QMP). Initial performance testing (acceptance testing) is required upon installation. All facilities must maintain a documented QC program and must comply with the minimum frequencies of testing outlined in the 2015 ACR Magnetic Resonance Imaging (MRI) Quality Control Manual.
The ongoing QC program assesses relative changes in system performance as determined by the technologist, service engineer, qualified medical physicist/MR scientist, or supervising physician. A qualified medical physicist/MR scientist must have the responsibility for overseeing the equipment quality control program and for monitoring performance upon installation and routinely thereafter. All ACR international recognized facilities must maintain a documented quality control (QC) program and must comply with the minimum frequencies of testing outlined in the 2015 ACR Magnetic Resonance Imaging (MRI) Quality Control Manual. There are no QC tests specific to breast MR, as distinct from those required for general MRI.
Although many of the procedures and action criteria outlined in the 2015 ACR Magnetic Resonance Imaging (MRI) Quality Control Manual were written specifically for the ACR MRI Accreditation Phantom, the ACR understands that the use of this phantom may not be possible for all QC in breast imaging. Some facilities use the ACR Small MRI Phantom for this purpose. The ACR leaves the choice of the QC phantom and the resultant action criteria to the facility. This decision must be made by the qualified medical physicist/MR scientist in cooperation with the system vendor.
Acceptance Testing
Acceptance testing is intended to measure quantifiable system parameters, which may then be compared to the manufacturer’s specifications and used to develop baseline performance. A complete evaluation of system performance should be conducted by a qualified medical physicist (QMP)/MR scientist after completion of installation and prior to patient imaging. This testing should be more comprehensive than periodic performance testing and should be consistent with current acceptance testing practices. It should include all of the technologist’s QC tests as well as the annual tests in the 2015 ACR Magnetic Resonance Imaging (MRI) Quality Control Manual and an evaluation of all coils, including all breast imaging and biopsy coils. Useful guidance is also available in a report from the MR Subcommittee Task Group of the AAPM.
Annual Medical Physicist Survey
All facilities applying for ACR international recognition must demonstrate compliance with the ACR requirements for QC by including a copy of the facility’s most recent Annual MRI System Performance Evaluation Summary (must be performed and signed by a medical physicist/MR scientist and must include evaluation of the weekly technologist QC and MR Safety Program Assessment). The medical physicist/MR scientist must provide a written report of findings of acceptance testing and performance evaluations to the responsible physician(s) and to the professional(s) responsible for service of the MRI equipment. If appropriate, the medical physicist/MR scientist should inform the site supervisor of the required service. Written reports must be provided in a timely manner consistent with the importance of any adverse findings. If use of the equipment poses imminent danger to patients or staff, the medical physicist/MR scientist must take immediate action to preclude use of the equipment.
The ACR realizes that surveys cannot usually be scheduled exactly on the anniversary date of the previous survey; therefore, a period of up to 14 months between surveys is acceptable. If the facility has been conducting QC for less than one quarter, the facility will submit whatever they have on these forms.
Additionally, if the Annual MRI System Performance Evaluation and/or QC files show performance deficits (e.g., problems with the system and/or data outside of the action limits), the facility must state what steps it has taken to correct the problems.
All QC testing must be carried out in accordance with the written procedures and methods outlined in the 2015 ACR Magnetic Resonance Imaging (MRI) Quality Control Manual. The evaluation must include, but is not limited to, the following:
Annual Medical Physicist's/MR Scientist's MR System Performance Evaluation | |
QC Test | Description |
Magnetic Field Homogeneity | Checks the uniformity of the main magnetic field strength (B0) over a designated volume. Inhomogeneities can contribute to geometrical distortion of images, adversely influence image quality, and compromise the signal-to-noise ratio (SNR) in some fast imaging sequences. |
Slice Position Accuracy | Checks the accuracy with which axial slices are positioned at specific locations utilizing a sagittal localizing image. The test determines whether the actual locations of acquired slices differ from their prescribed locations by substantially more than is normal for a well-functioning scanner. |
Slice Thickness Accuracy | Checks the prescribed slice thickness against that of the measured slice thickness. Poor slice thickness accuracy may not only suggest that slices are too thick or thin but can extend to factors such as incorrect image contrast or SNR. |
Radiofrequency Coil Checks | Checks the trade-off between maximizing image uniformity and enhancing SNR that is inherent to various types of radiofrequency coils. Tests should be performed on all coils used clinically (including breast coils) and include:
|
Soft-Copy Displays (Monitors) | Checks that display devices meet manufacturer’s published specifications for
|
Evaluation of QC Program | Provides an external assessment of QC, checks that appropriate actions are taken to correct problems, identifies areas where quality and QC testing may be improved and enables a comparison of QC practices with those of other MRI sites. |
Continuous Quality Control
A continuous QC program must be implemented for all MRI units and should be established with the assistance of a qualified medical physicist/MR scientist. The technologist must perform the QC tests listed below at a weekly minimum frequency. The medical physicist/MR scientist should identify the person responsible for performing the tests and may choose to increase the frequency of testing based on the facility and MRI usage. If any QC parameter being monitored falls outside of the control limits, corrective action should be taken. A medical physicist/MR scientist should be available to assist in prescribing corrective actions for unresolved problems. The technologist weekly QC program must include, but not be limited to, the following:
Technologist's Weekly MRI Quality Control | |
QC Test | Description |
Table Positioning | To determine that the MRI scanner is functioning properly with regard to performing patient set up |
Setup and Scanning | To determine that the MRI scanner is functioning properly with regard to performing data entry and prescan tasks |
Center (Central) Frequency | To determine that the MRI system is set on-resonance; the effects of off-resonance relate primarily to system sensitivity and appear as a reduction in image SNR |
Transmitter Gain or Attenuation | To determine whether there are problems with the radiofrequency chain (coil RF calibration) |
Geometric Accuracy | To determine whether the geometric relationships of the MR image are in error (gradient calibration) |
High Contrast (Spatial) Resolution | To assess the scanner’s ability to resolve small objects |
Low Contrast Resolution (Detectability) | To assess the extent to which objects of low-contrast are discernible in the imagesNOTE: SNR is an acceptable alternative to LCD scoring for daily/weekly phantom QC. However, LCD scores must be included in the Annual System Performance Evaluation. |
Artifact Analysis | To assess the presence of artifacts that may be early indicators of declining MRI system performance |
Film (Hardcopy Image) QC | To ensure artifact-free laser films are produced with consistent gray levels that match the image appearance on the filming console |
Visual Checklist | To ensure the MRI system patient bed transport, alignment and system indicator lights, RF room integrity, emergency cart, safety lights, signage and monitors are present and working properly and are electrically and mechanically stable |
If your facility does not have laser printer capability for Breast MRI, there is no need to perform QC for a laser printer. Just indicate that you do not use a laser printer when you complete the application.
MRI Safety
Safety guidelines, practices, and policies must be written, enforced, reviewed and documented at least annually by the MR supervising physician. For guidance, see the ACR’s Manual on MR Safety and the ACR Manual on Contrast Media. The annual medical physicist/MR scientist performance summary must also include an assessment of the MRI safety program (signage, access control, screening procedures and cryogen safety) as well as an inspection of the physical and mechanical integrity of the system.
The use of remote MR system operation does not, in any way, diminish the obligations of the site to provide safe MR patient care.
Preventative Maintenace
Preventive maintenance must be scheduled, performed and documented by a qualified service engineer on a regular basis. Service performed to correct system deficiencies must also be documented and service records maintained by the MR site.
Clinical Image Evaluation and Labeling
Facilities must review 1 typical clinical examination from each module performed and attest to meeting the ACR clinical image quality and labeling requirements found in the links below.
Exam Requirements
MRI Exam-Specific Parameters: Head and Neck Module (Revised 4-6-2022) : Accreditation Support
MRI Exam-Specific Parameters: Spine Module (Revised 5-10-2022) : Accreditation Support
MRI Exam-Specific Parameters: MSK Module (Revised 3-5-2025) : Accreditation Support
MRI Exam-Specific Parameters: Body Module (Revised 9/11/2020) : Accreditation Support
MRI Exam-Specific Parameters: MRA Module (Revised 4-10-2024) : Accreditation Support
MRI Exam-Specific Parameters: Cardiac Module (Revised 8-10-2023) : Accreditation Support
MRI Exam-Specific Parameters: Breast (Revised 3-19-2025) : Accreditation Support
Pulse Sequence and Image Contrast
The type of pulse sequence (e.g. conventional SE, multishot RARE or gradient echo) and the precise imaging parameters (e.g. TR, TE, FA, ETL, etc.) are not specified and are left to the discretion of the imaging facility unless otherwise stated.
Our articles on examination-specific parameters detail the sequences considered to be the minimum necessary for a quality examination.
All sequences must demonstrate sufficient Signal to Noise (SNR) and not appear too grainy. If contrast is required, it is very important that patient selection is appropriate for the examination using contrast. Please refer to the https://www.acr.org/Clinical-Resources/Clinical-Tools-and-Reference/radiology-safety/mr-safety for more information on IV contrast safety.
Anatomic Coverage and Imaging Planes
Proper anatomic coverage and imaging planes are important components of clinical MRI exams. The minimum sets of images required for each examination and the anatomy to be included on those images are listed in our articles on examination-specific parameters.
Spatial/Temporal Resolution
The spatial resolution necessary for quality MRI images varies by examination and sequence. MRI facilities must use the determinants and formulas listed below to determine the spatial resolution of their clinical MRI examinations. The five determinants of pixel/voxel dimensions in an MRI examination are:
Slice thickness (ST)
Field of view along the phase encode direction (FOVp)
Field of view along the frequency encode direction (FOVf)
Number of phase encoding steps (Np) (This is your phase matrix)
Number of frequency encoding steps (Nf) (This is your frequency or read matrix)
If you are using a rectangular FOV, your phase FOV will be different from your frequency FOV. This may also be true for your matrix. If you are not sure, consult your manufacturer.
The determinants of temporal resolution are:
Speed of frames per millisecond
Temporal resolution = msec/frames
For cine images, the number of views per segment (nvs) or segmentation factor also controls acquired temporal resolution
Note that most manufacturers use phase sharing (view sharing techniques) to increase the visual smoothness of the cine movies. Our articles on examination-specific parameters refer to temporal resolution before these view sharing techniques.
With view sharing, images that are acquired every 80 msec can be interpolated, so that the cine display shows a new image every 40 msec (or less). However, each image still contains 80 msec worth of data.
To determine the temporal resolution, use this formula: Temporal resolution (cine) = TR x NVS (Where NVS is the number of views per segment, or segmentation factor and TR is the intrinsic or minimum TR of the pulse sequence). Some manufacturers may not display this TR value. If in doubt, please contact your manufacturer’s application specialist.
Image Artifacts
Artifacts on any image may interfere with image interpretation. Although some artifacts may be unavoidable on certain images (e.g. susceptibility artifacts near sinuses on T2 weighted brains); others may be indicators of inadequate equipment or lack of preventive maintenance at an MRI facility. The artifacts listed in the table below are among the most common. All of the images should be assessed to determine if any of these artifacts are present, especially if they could potentially compromise the diagnostic value of the images. Your examinations will be reviewed for excessive artifacts that may interfere with image quality.
Common Image Artifacts | |
Aliasing | The image appears wrapped around into itself. This is due to a large body portion included in a too small FOV. |
Parallel Imaging | Mismatches between the anatomy on calibration images and diagnostic images appear as chemical shift, motion, ghosting and misregistration along the phase-encoding direction in the middle of the FOV. |
Truncation (Edge Ringing) | Periodic parallel lines or ringing adjacent to borders or tissue discontinuity, in either the phase and/or frequency encoding directions. This is due to a small matrix. |
Black Boundary (India Ink) | Well-defined black contours outlining regions of MR anatomy, without corresponding anatomical structure. |
Heterogeneous Brightness (Shading) | This is due to RF heterogeneity, improper patient positioning, or metal in the magnet or on the patient. |
Heterogeneous Fat Suppression | Uneven darkening of the fat signal in different portions of the image set. This may be due to either a heterogeneous magnetic field or a heterogeneous RF field. |
Susceptibility | Localized field distortion or non-uniformities produced by differing tissue magnetic susceptibility (especially at air-tissue interfaces). |
Chemical Shift | Occurs along the frequency encoding axis at fat/water soft tissue interfaces as a thin intense band of high signal or low signal. |
Ghosting | Periodic replication of partial copies of images of the original structure along the phase encoding axis due to motion. It includes artifacts from swallowing (C-spine), respiration and peristalsis (L-spine), CSF pulsation (brain and spine), vascular pulsation (brain and knee) and cardiac motion (T-spine). |
Geometric Distortion | Size, orientation or shape is not accurately represented on the image. |
Excessive Filtering | Excessive smoothing using software to reduce apparent noise in the image. Excessive filtering or smoothing obscures true anatomical structure and/or contrast. |
Misregistration of 2D Images | Consecutive 2D images do not line up so some anatomy is skipped and other regions are imaged twice. This can also be a particularly serious problem on 2D time-of-flight MRA MIPs. |
Misregistration of Subtracted Images | On subtracted images, there is incomplete subtraction of the background tissue signal with prominent signal at edges that do not align properly. |
Ringing | Accentuation of edges due to either under sampling of k-space (not enough phase encoding steps) or at the leading edge of the bolus on an enhanced 3D MRA study due to IV contrast being present during acquisition of peripheral k-space but not as much during acquisition of the center of k-space. |
Stair Step (Venetian Blind Effect) | In MRA, a vessel goes obliquely through slices, due to slice thickness and vessel size. Venetian blind occurs on multi slab MRA (typically on reformations and MIPs), when the adjacent slabs are not properly and seamlessly overlapped. |
Reformatting Artifacts | Improper MIP and reformations may give the false appearance of vessel occlusion or stenosis when it is only partially included in the MIP volume. Superimposed vessels may falsely appear stenotic on MIP due to stealing of voxels at the vessel edges. Stair step artifact may occur on oblique reconstruction when the slices are too thick or there is insufficient zero filling. |
ECG Lead Artifacts | The ECG leads used for cardiac gating should not produce excessive artifacts that would interfere with the interpretation of the image. |
RF Leak or "Zipper" Artifact | Linear hyperintensity parallel to the phase encoding direction often caused by unwanted sources of RF signals originating within (e.g., light bulb failure) or outside (e.g. inadequate RF shielding) the scanner room. |
Echo Train Blurring | Image blurring due to excessively long echo spacing and/or echo train length. |
Peripheral signal artifacts | Star artifact: A bright spot close to the image center originates very far from isocenter because FID signal from RF 180 pulse or SAT pulse is not crushed out and aliases back into image center.Annefact artifact: Smeared, bright, ribbon ghosting signals in the phase-encoding direction are uncompensated eddy currents that also originate far from isocenter where gradients are non-linear. |
Other | There are other artifacts that are not as common as those listed above but which may be important. |
Exam Identification and Labeling
Patient and technical data must be displayed on the images or be available in the DICOM header.
Exam Identification | |||
Each Exam | Each Sequence | Each Image | |
|
The following labels are not required, but are strongly recommended for each sequence:
|
| |
Policies and Procedures
In addition to the general policies and procedures noted in the instruction article, the facility must also have the following MR specific policies and procedures:
Documentation listing the MRI medical director or MR safety officer's name and responsibilities
MRI staffing policy
MRI screening forms for patients and representatives
Educating MRI, non-MRI and emergency personnel to include Level 1 and Level 2 training
Ongoing education for MRI
Physican Quality Assurance
Facilities must meet the Physician Quality Assurance requirements found in Physician QA Requirements: CT, MRI, Nuclear Medicine/PET, Ultrasound (Revised 1-3-2024): Accreditation Support (acr.org).
Footnotes:
[1] Occasional readers who are providing imaging services to and for the practice readers are not required to meet continuing experience requirements. However, the reads of all occasional readers combined should not exceed 5% of the total volume of reads per practice and per modality. There must be an active written review process in place at the institution for occasional readers based on each institution’s credentialing requirements.
[2] Biopsies performed under MRI guidance may be counted toward initial and continuing experience. A bilateral breast exam of one patient is considered one examination.
[3] SNR is an acceptable alternative to LCD scoring for daily/weekly phantom QC. However, LCD scores must be included in the Annual System Performance Evaluation.