Description
MRI scanners with a field strength of greater than 1.0 Tesla (T) are considered high field. The typical high-field MRI units in clinical practice range between 1.0 – 3.0 Tesla. In October 2017, the FDA cleared the first 7 T MRI units. The definition of mid- and low-field MRI is more variable with mid-field units having a lower field strength range of 0.3 to 0.5 and an upper limit under 1.0 T. Low-field units have field strengths below 0.3 to 0.2 T. The major disadvantage of low-field strength MRI relative to higher field scanners is lower signal to noise ratios, less homogeneity in the magnetic field, lower detection of calcification, hemorrhage or gadolinium enhancement. Lee et al. showed that low-field (< 0.5 T) units were effective in evaluating medial meniscal, anterior cruciate ligament, and rotator cuff tears but not effective for evaluating lateral meniscal tears, osteochondral defects, or shoulder superior labrum-anterior posterior (SLAP) ligament complex pathology.

Policy
Low-field MRI services are not considered to be MEDICALLY NECESSARY.

References

1. Lee CS, Davis SM, McGroder C, et al. Analysis of low-field magnetic resonance imaging scanners for evaluation of knee pathology based on arthroscopy. Orthop J Sports Med. December 2013; 1(7):2325967113513423. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4555514/. Retrieved January 10, 2018.
2. Lee CS, Davis SM McGroder C, et al. Analysis of low-field MRI scanners for evaluation of shoulder pathology based on arthroscopy. Orthop J Sports Med. July 2014; 2(7):2325967114540407. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4588525/. Retrieved January 10, 2018.
3. Low-field Disadvantages from MRIquestions.com website. http://mriquestions.com/disadvantages.html. Retrieved December 28, 2017.
4. US Food and Drug Administration (FDA). News Release: FDA clears first 7T magnetic resonance imaging device. https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm580154.htm. Released October 12, 2017. Retrieved 12/28/17.

Coding Section

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive. 

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross Blue Shield Association technology assessment program (TEC) and other nonaffiliated technology evaluation centers, reference to federal regulations, other plan medical policies, and accredited national guidelines.

"Current Procedural Terminology © American Medical Association. All Rights Reserved" 

History From 2019 Forward