Medical Policy


Subject: PET/MRI
Document #: RAD.00061 Publish Date:    12/12/2018
Status: Reviewed Last Review Date:    11/08/2018


This document addresses combination positron emission tomography/magnetic resonance imaging (PET/MRI) technology with dedicated scanners, such as the Biograph mMR System (Siemens Medical Solutions U.S.A., Inc., Malvern, PA). The Biograph mMR System is a combined Magnetic Resonance Diagnostic Device (MRDD) and Positron Emission Tomography (PET) scanner that provides a combined approach to imaging anatomical, functional and biochemical characteristics of disease.

Position Statement

Investigational and Not Medically Necessary:

The use of combined PET/MRI imaging technology is considered investigational and not medically necessary for all indications.


The Siemens Biograph mMR (Siemens Medical Solutions U.S.A., Inc., Malvern, PA) System obtained clearance from the U.S. Food and Drug Administration (FDA) on June 8, 2011 as a combined magnetic resonance diagnostic device (MRDD) and a PET scanner that provides registration and fusion of high resolution physiologic and anatomic information, acquired simultaneously and isocentrically. The combined system maintains the independent functionality of the magnetic resonance (MR) and the PET devices, allowing for single modality MR or PET imaging. The MR is intended to produce transverse, sagittal, coronal and oblique cross-sectional MR images, spectroscopic or spectra images, and displays the internal structure and function of the human body.  Other physical parameters derived from the images may also be produced. Depending on the region of interest, approved contrast agents may be used.  This system may also be used for imaging during interventional procedures when performed with MR compatible devices, such as MR-safe biopsy needles. The PET images and measures the distribution of PET radiopharmaceuticals in humans to aid the physician in determining various metabolic (molecular) and physiologic functions within the human body for evaluation of diseases and disorders such as, but not limited to, cardiovascular disease, neurological disorders and cancer.

According to the FDA labeling for the Siemens Biograph mMR System:

These systems are intended to be utilized by appropriately trained health care professionals to aid in the detection, localization, and diagnosis of diseases and disorders. The combined system utilizes the MR for radiation-free attenuation correction maps for PET studies. The system provides inherent anatomical reference for the fused PET and MR images due to precisely aligned MR and PET image coordinate systems (FDA, 2011).

The International Cancer Imaging Society commented as follows:

A synergistic combination of scanning characteristics sounds promising. However, the exact clinical value has not yet been fully established. The role of PET/CT image fusion must be weighed carefully against other available modalities. When available, PET/CT currently appears the diagnostic tool of choice. In the near future, combined PET/MRI may further enhance the diagnostic algorithm (Vogel, 2005).

There are technical challenges to combined PET and MRI image acquisition including attenuation correction (AC) of whole-body PET data in combined PET/MRI tomographs which are being investigated. 

In 2012, exploratory analysis was conducted that evaluated the outcomes of PET/MRI in 21 subjects with soft tissue sarcoma (STS) in different treatment settings: (a) neoadjuvant setting, (b) metabolic-driven local therapy in metastatic sarcoma, and (c) palliative treatment.  An Ingenuity PET/MR system (Philips Healthcare) was used.  It combines a 3-Tesla MRI and a PET scanner with time-of-flight technology.  Results were reported as the first such analysis of STS examined with whole-body-PET/MRI.  Results showed high contrast imaging without significant artifacts or distortions.  Four subjects with high-risk sarcoma (3 rhabdo, 1 pleomorphic) completed their planned neoadjuvant therapy.  Change in tumor size did not correlate with pathologic response, whereas surgical outcome was well predicted in metabolic changes.  Due to this finding, the preplanned course of chemotherapy for 1 subject was changed, and in 3 individuals, with a remnant metabolic activity in a single spot, surgical resection of a single metastatic lesion was performed or local radiotherapeutic treatment was given.  In 3 subjects who had stable disease after first-line treatment, persisting metabolic activity on the PET/MRI resulted in a change in the treatment regimen which ultimately resulted in decreased metabolic activity and tumor regression.  The authors concluded that whole-body PET/MRI is feasible in STS and may provide valuable information in treatment, monitoring and prognosis of STS.  Additional prospective studies of PET/MRI for STS are needed (Richter, 2012).

To date, few studies have focused on this combined PET/MRI technology (Gatidis, 2016; Heusch, 2013; Malone, 2011; Martinez-Moller, 2009; Ponisio, 2016; Schleyer, 2010; Schmidt, 2013; Sher, 2016; Xin, 2016).  At the present time, additional research is needed to resolve the technical issues and inform regarding the most appropriate applications for combined PET/MRI imaging technology.


Potential clinical applications for PET/MRI imaging technology include the early identification and staging of malignancies, therapy planning, and treatment. Proposed advantages of PET/MRI combined imaging include reduced total radiation dose and increased soft-tissue contrast visualization. Although the PET component will still require the injection of a radioactive contrast agent to obtain the scan, there is no ionizing radiation used during the MRI scan. It is reported that PET/MRI will allow for imaging at a significantly lower total radiation dose compared to PET/CT (computed tomography) which is particularly advantageous for children and also adults undergoing multiple scans, as part of the diagnostic workup of certain conditions. Another purported advantage involves minimizing changes in the subject’s position between the PET and MRI test segments which will potentially improve accuracy in the comparative interpretation of scanned images.


Attenuation: Refers to the decrease or loss in energy of radiation strength that occurs as the distance from the source increases and the radiation passes through matter. This is due to absorption or scattering in three dimensions.

Magnetic resonance imaging (MRI): A diagnostic imaging modality that uses magnetic and radiofrequency fields to image the anatomy of body tissue non-invasively.

Positron emission tomography (PET): An imaging technique that measures the concentration of chemicals injected into the body and provides images of the chemical function of body parts of interest.


The following codes for treatments and procedures applicable to this document are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services are Investigational and Not Medically Necessary:
When the code(s) describes a procedure indicated in the Position Statement section as investigational and not medically necessary.




Unlisted miscellaneous procedure, diagnostic nuclear medicine [when specified as mMR combination PET/MRI imaging]



ICD-10 Diagnosis



All diagnoses


Peer Reviewed Publications:

  1. Antoch G, Bockisch A. Combined PET/MRI: a new dimension in whole-body oncology imaging. Eur J Nucl Med Mol Imag. 2009; 36 Suppl 1:S113-S120.
  2. Blanchet EM, Millo C, Martucci V, et al. Integrated whole-body PET/MRI with 18F-FDG, 18F-FDOPA, and 18F-FDA in paragangliomas in comparison with PET/CT: NIH first clinical experience with a single-injection, dual-modality imaging protocol. Clin Nucl Med. 2014; 39(3):243-250.
  3. Eiber M, Takei T, Souvatzoglou M, et al. Performance of whole-body integrated 18F-FDG PET/MR in comparison to PET/CT for evaluation of malignant bone lesions. J Nucl Med. 2014; 55(2):191-197.
  4. Fraioli F, Shankar A, Hargrave D, et al. 18F-Fluoroethylcholine (18F-Cho) PET/MRI functional parameters in pediatric astrocytic brain tumors. Clin Nucl Med. 2015; 40(1):e40-e45.
  5. Gatidis S, Schmidt H, Gücke B, et al. Comprehensive oncologic imaging in infants and preschool children with substantially reduced radiation exposure using combined simultaneous ¹⁸F-Fluorodeoxyglucose positron emission tomography/magnetic resonance imaging: A direct comparison to ¹⁸F-Fluorodeoxyglucose positron emission tomography/computed tomography. Invest Radiol. 2016; 51(1):7-14.
  6. Heusch P, Buchbender C, Köhler J, et al. Correlation of the apparent diffusion coefficient (ADC) with the standardized uptake value (SUV) in hybrid 18F-FDG PET/MRI in non-small cell lung cancer (NSCLC) lesions: initial results. Rofo. 2013; 185(11):1056-1062.
  7. Hicks RJ, Lau EW. PET/MRI: a different spin from under the rim. Eur J Nucl Med Mol Imag. 2009; 36 Suppl 1:S10-S14.
  8. Malone IB, Ansorge RE, Williams GB, et al. Attenuation correction methods suitable for brain imaging with a PET/MRI scanner: a comparison of tissue atlas and template attenuation map approaches. J Nucl Med. 2011; 52(7):1142-1149.
  9. Martinez-Moller A, Souvatzoglou M, Delso G, et al. Tissue classification as a potential approach for attenuation correction in whole-body PET/MRI: evaluation with PET/CT data. J Nucl Med. 2009; 50(4):520-526.
  10. Moy L, Noz ME, Maguire GQ Jr, et al. Role of fusion of prone FDG-PET and magnetic resonance imaging of the breasts in the evaluation of breast cancer. Breast J. 2010; 16(4):369-376.
  11. Nagarajah J, Jentzen W, Hartung V, et al. Diagnosis and dosimetry in differentiated thyroid carcinoma using 124I PET: comparison of PET/MRI vs. PET/CT of the neck. Eur J Nucl Med Mol Imag. 2011; 38(10):1862-1868.
  12. Nakajo K, Tatsumi M, Inoue A, et al. Diagnostic performance of fluorodeoxyglucose positron emission tomography/magnetic resonance imaging fusion images of gynecological malignant tumors: comparison with positron emission tomography/computed tomography. Japan J Radiol. 2010; 28(2):95-100.
  13. Ponisio MR, McConathy J, Laforest R, Khanna G. Evaluation of diagnostic performance of whole-body simultaneous PET/MRI in pediatric lymphoma. Pediatr Radiol. 2016; 46(9):1258-1268.
  14. Ratib O, Beyer T. Whole-body hybrid PET/MRI: ready for clinical use? Eur J Nucl Med Mol Imaging. 2011; 38(6):992-995.
  15. Rauscher I1, Eiber M, Fürst S, et al. PET/MR imaging in the detection and characterization of pulmonary lesions: technical and diagnostic evaluation in comparison to PET/CT. Nucl Med. 2014; 55(5):724-729.
  16. Richter S, Platzek I, Beuthien-Baumann B, et al. Whole-body PET/MR in soft tissue sarcoma (STS) patients. J Clin Oncol. 2012; 30:(15):suppl abstr 10068. Available at: Accessed on September 26, 2018.
  17. Salamon N, Kung J, Shaw SJ, et al. FDG-PET/MRI coregistration improves detection of cortical dysplasia in patients with epilepsy. Neurology. 2008; 71(20):1594-1601.
  18. Sauter AW, Wehrl HF, Kolb A, et al. Combined PET/MRI: one step further in multimodality imaging. Trends Mol Med. 2010; 16(11):508-515.
  19. Schleyer PJ, Schaeffter T, Marsden PK. The effect of inaccurate bone attenuation coefficient and segmentation on reconstructed PET images. Nucl Med Com. 2010; 31(8):708-716.
  20. Schmidt H, Brendle C, Schraml C, et al. Correlation of simultaneously acquired diffusion-weighted imaging and 2-deoxy-[18F] fluoro-2-D-glucose positron emission tomography of pulmonary lesions in a dedicated whole-body magnetic resonance/positron emission tomography system. Invest Radiol. 2013; 48(5):247-255.
  21. Sher AC, Seghers V, Paldino MJ, et al. Assessment of sequential PET/MRI in comparison with PET/CT of pediatric lymphoma: A prospective study. AJR Am J Roentgenol. 2016; 206(3):623-631.
  22. Tatsumi M, Isohashi K, Onishi H, et al. F-FDG PET/MRI fusion in characterizing pancreatic tumors: comparison to PET/CT. Int J Clin Oncol. 2011; 16(4):408-415.
  23. Vogel WV, Wiering B, Corstens FHM, et al. Colorectal cancer: the role of PET/CT in recurrence. Canc Imag. 2005; 5(A):S143-S149.
  24. Xin J, Ma Q, Guo Q, et al. PET/MRI with diagnostic MR sequences vs PET/CT in the detection of abdominal and pelvic cancer. Eur J Radiol. 2016; 85(4):751-759.
  25. Yi CA, Lee KS, Lee HY, et al. Coregistered whole body magnetic resonance imaging-positron emission tomography (MRI-PET) versus PET-computed tomography plus brain MRI in staging resectable lung cancer: comparisons of clinical effectiveness in a randomized trial. Cancer. 2013; 119(10):1784-1791.

Government Agency, Medical Society, and Other Authoritative Publications:

  1. Centers for Medicare and Medicaid Services (CMS). Decision memo for positron emission tomography. CAG-00065R2. March 7, 2013. Available at: Accessed on September 26, 2018.
  2. Stanford University. PET/MRI Imaging of Cardiac Sarcoidosis. NLM Identifier: NCT03103490. Last updated April 12, 2018. Available at: Accessed on September 24, 2018.
  3. U.S. Food and Drug Administration. Center for Devices and Radiological Health (CDRH) 510(k) Premarket Notification Database. Siemens Biograph mMR. Summary of Safety and Effectiveness. No. K103429. Rockville, MD: FDA. June 8, 2011. Available at: Accessed on September 26, 2018.

PET/MRI, Positron Emission Tomography/Magnetic Resonance Imaging
Siemens Biograph mMR

The use of specific product names is illustrative only. It is not intended to be a recommendation of one product over another, and is not intended to represent a complete listing of all products available.

Document History






Medical Policy & Technology Assessment Committee (MPTAC) review.



Hematology/Oncology Subcommittee review. The Description/Scope, Rationale and References sections were updated.



MPTAC review.



Hematology/Oncology Subcommittee review. The document header wording was updated from “Current Effective Date” to “Publish Date.” The Rationale and References sections were updated. 



MPTAC review. 



Hematology/Oncology Subcommittee review. References were updated.



MPTAC review.



Hematology/Oncology Subcommittee review. References were updated. Removed ICD-9 codes from Coding section.



MPTAC review.



Hematology/Oncology Subcommittee review. References were updated.



MPTAC review.



Hematology/Oncology Subcommittee review. References were updated.



MPTAC review.



Hematology/Oncology Subcommittee review. References were updated.



MPTAC review. MPTAC approved new policy.



Hematology/Oncology Subcommittee review. Initial document development.