Testing Overview: MRI (Revised 10-21-2024)

Revision History

Successful accreditation is a team effort involving the lead supervising physician, MR technologist and qualified medical physicist.

There are three portions to your ACR MR Accreditation submission:

1. Annual System Performance Evaluation Summary (see our article on MR QC)

2. Clinical Testing

3. Phantom Testing

To achieve ACR MR accreditation, an MR unit must pass both the clinical and phantom image quality tests. Follow all instructions for every unit being reviewed for accreditation. Every unit must apply for all modules routinely performed on each unit for a facility to be accredited. Please see our article on Modalities with Low Volume or Emergency Use as needed.

The application for ACR MR Accreditation is available through ACRedit, the ACR’s online accreditation site. If your facility has never applied for accreditation before, you will “register” as a new facility. New facilities will be assigned a unique identification number (MRAP#) after the online application is submitted. This number appears on all correspondence from the ACR and your online records. Please use this number on all submitted materials and to identify your facility when contacting the ACR for assistance.

After your application is processed, an online testing packet will be activated which will contain all clinical and phantom data forms required for accreditation review. Your facility will receive an email with a link to the online testing packet as well as a link to the electronic PDF version of the MR Quality Control Manual.

The following items will assist you in gathering data for your accreditation submission:

1. Clinical Data Form

2. Large Phantom Data Form

3. Large/Medium Phantom Data Form

4. Small Phantom Data Form

These forms are attached below. These are generic forms designed to assist you in gathering data. Do not submit these forms. You must login to ACRedit to enter the data in your online testing package and submit the package online. 

The online testing packet has the image submission due date, 45 calendar days from the online testing packet link that was emailed to your facility. You must collect your images and submit your testing packet by that date. Failure to meet this due date will jeopardize completion of your accreditation. Thus, if your facility is renewing its accreditation, we cannot guarantee completion in a timely fashion before your ACR certificate expires. If your site cannot submit the required materials by your due date, contact the ACR immediately.

Any MRI facility may apply for MRI accreditation. For small, extremity-only scanners, there is a smaller phantom that your scanner can accommodate. Simply indicate on your application that your scanner is only capable of extremity scans. If you are submitting on a magnet capable of breast imaging only (i.e., Aurora) contact the ACR for information regarding submission of phantom images.

All clinical and phantom examinations submitted must have been performed within six 6 months of the date that the testing package link was released to the facility. No images will be accepted for review that predate this date by more than six months.

Clinical Image Testing: Overview

Prior to beginning the accreditation process, your supervising physician should ensure that all of your facility’s protocols meet the minimum requirements listed in our article on clinical image testing, as well as our articles detailing examination requirements by module. Please note the following as you select images for submission:

• Select examples of your best work and have them approved by your supervising physician prior to submission. Your supervising physician should review all materials submitted for accreditation. All images must demonstrate adequate positioning, resolution, noise, patient and facility identification, and lack of artifacts.

• Submit normal or near normal examinations if possible (with the exception of the Breast MR exam. See note below). The submitted examinations should demonstrate as little pathology as possible.  The purpose of the accreditation evaluation is to review the quality of the practice of MRI at applicant facilities and not to comment on abnormal findings. The ACR is not responsible for clinical findings shown on the studies. Submitting abnormal examinations (except for the Breast MR exam) may significantly delay the accreditation process. 

  Note:  A known enhancing biopsy-proven carcinoma clearly visible in the breast parenchyma is required for the Breast MR exam. 

• IMPORTANT: Submit only the sequences required for accreditation and any corresponding reconstructed images. 

• The submission of examinations performed on models or volunteers is strictly prohibited and may jeopardize accreditation. Any clinical image submitted for accreditation review must be of an actual patient who needed the examination. Use of volunteers or models, including staff from your facility, is prohibited and may result in withholding, denial or revocation of accreditation. Attempting to “pass off” images taken from a volunteer/model as clinical images from a patient may constitute fraud.

• Images submitted for each individual examination must be from the same patient (i.e. all brain images must be from the same brain exam) 

If it is determined you need to change exams the change request must be submitted as a support ticket request   before submitting your testing package. There, you may select the topic/category of exam change, fill out the modality ID number and unit (if applicable) and specify the exam or module you wish to add, remove or change. You will be contacted once the change is complete to upload and submit your testing package.  

Before the collection of any images can begin, first evaluate your clinical image spatial resolution, and compare it with ACR criteria. Our article on clinical testing lists the formulas to determine spatial and temporal resolution. If your site determines that you need to adjust your protocols, please make changes before proceeding to phantom testing. Please be aware that further changes in clinical image spatial resolution may be warranted based on evaluation of phantom images performed during the test image collection phase.

Please note that if you make any alterations in any resolution parameters (matrix, field of view or slice/slab thickness) as a result of ACR recommendations, it will result in a modification of the voxel volume, the signal-to-noise ratio (SNR) of the image and the amount of partial volume averaging exhibited in the image. Alterations in the number of phase encoding steps (Np) affects scan time, while alterations in the number of frequency encoding steps (Nf) may affect the maximum number of slices as well as the minimum possible TE for the imaging sequence. Your site will be responsible for making any necessary corresponding changes in scan protocols to maintain image quality.

The ACR provides comprehensive practice parameters and technical standards for MR imaging which are independent of the accreditation program. As needed, please visit the ACR website for a listing of practice parameters and technical standards. Additional guidance and educational materials may be found at the following webpages:

• MR Safety - American College of Radiology

Phantom Testing: Overview

Clinical image review and phantom review are intended to complement each other for a comprehensive evaluation of the quality of MRI services. Depending on the type of scanner, one of three phantoms will be required for the facility to scan and submit images on. It is strongly recommended to consult with the facility's Qualified Medical Physicist (QMP/MR Scientist) to determine which phantom to utilize. The decision is based on the head coil routinely used for clinical brain imaging on the scanner. It must be the largest phantom that fits inside the head coil used clinically. If the routinely used head coil for brain imaging cannot accommodate the medium (or large) phantom, phantom images may be acquired using an alternative clinical head coil with the largest phantom that fits inside the head coil.  Facilities with scanners that do not have a head coil and/or do not routinely perform brain imaging should use the small phantom in the knee coil to obtain phantom images for accreditation review. The small phantom scanned in the knee coil is also used for extremity-only units. The ACR will provide more detailed information in the testing materials for each unit once the application is processed.

At this time, the phantom can be purchased by MRI facilities that apply for accreditation, MRI equipment manufacturers, and consulting physicists or MR scientists only. For your convenience, the large, medium and small MR phantom order forms are attached to the respective phantom testing instructions. The fees are listed on the forms.

Each facility is required to submit phantom images for each unit using the ACR protocols for T1 and T2 weighting and phantom images using its own routine T1 and T2 weighted scan protocol. Please review the phantom scanning instructions for the size phantom you are submitting (large, medium, or small) and follow them carefully before obtaining images for submission to the accreditation program. If you have any questions about the phantom scanning instructions, please contact the ACR.

The images and testing data will be used to assess:

• Limiting high-contrast spatial resolution

• Slice thickness accuracy

• Distance measurement and accuracy

• Signal uniformity

• Image ghosting ratio

• Low-contrast detectability

• Slice positioning accuracy

• Image artifacts 

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