Medical Policy

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.

Investigational and Not Medically Necessary:

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

PET/MRI has become increasingly investigated as an alternative to PET/CT imaging. This procedure involves less radiation exposure than PET/CT imaging, which is an important factor to consider, especially when radiation-sensitive populations are involved.

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; Ruhlmann, 2016; Schleyer, 2010; Schmidt, 2013; Sekine, 2017; Sher, 2016; Xin, 2016). Additional hybrid imaging technologies are under investigation, such as multiparametric magnetic resonance imaging (mpMRI) and three-dimensional T1-weighted high-resolution isotropic volume examination (3D-THRIVE) with some preliminary trials data that has shown comparable or superior diagnostic performance to PET/CT (Gődény, 2016; Yoo, 2018).

At the present time, additional research from large, robust, randomized prospective trials is needed to resolve the technical issues and inform regarding the most appropriate applications for combined PET/MRI imaging technologies.

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.

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. Evangelista L, Briganti A, Fanti S, et al. New clinical indications for (18)F/(11)C-choline, new tracers for Positron Emission Tomography and a promising hybrid device for prostate cancer staging: A systematic review of the literature. Review Eur Urol. 2016; 70(1):161-175.
5. 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.
6. 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.
7. Gődény M, Lengyel Z, Polony G, et al. Impact of 3T multiparametric MRI and FDG-PET-CT in the evaluation of occult primary cancer with cervical node metastasis. Cancer Imaging. 2016; 16(1):38.
8. Guberina N, Hetkamp P, Ruebben H, et al. Whole-Body integrated [68 Ga] PSMA-11-PET/MR imaging in patients with recurrent prostate cancer: comparison with whole-body PET/CT as the standard of reference. Comparative Study Mol Imaging Biol. 2020; 22(3):788-796.
9. 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.
10. 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.
11. 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.
12. 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.
13. 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.
14. 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.
15. 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.
16. 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.
17. Ratib O, Beyer T. Whole-body hybrid PET/MRI: ready for clinical use? Eur J Nucl Med Mol Imaging. 2011; 38(6):992-995.
18. Rauscher I, 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.
19. 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.
20. Ruhlmann V, Ruhlmann M, Bellendorf A, et al. Hybrid imaging for detection of carcinoma of unknown primary: a preliminary comparison trial of whole-body PET/MRI versus PET/CT. Eur J Radiol. 2016; 85(11):1941-1947.
21. 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.
22. 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.
23. 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.
24. 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.
25. Scobioala S, Kittel C, Wolters H, et al. Diagnostic efficiency of hybrid imaging using PSMA ligands, PET/CT, PET/MRI and MRI in identifying malignant prostate lesions. Ann Nucl Med. 2021; 35(5):628-638.
26. Sekine T, Barbosa FG, Sah BR, et al. PET/MR outperforms PET/CT in suspected occult tumors. Clin Nucl Med. 2017; 42(2):e88-e95.
27. 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.
28. 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.
29. Vogel WV, Wiering B, Corstens FHM, et al. Colorectal cancer: the role of PET/CT in recurrence. Cancer Imaging. 2005; 5(A):S143-S149.
30. 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.
31. 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.
32. Yoo MG, Kim J, Bae S, et al. Detection of clinically occult primary tumors in patients with cervical metastases of unknown primary tumors: comparison of three-dimensional THRIVE MRI, two-dimensional spin-echo MRI, and contrast-enhanced CT. Clin Radiol. 2018; 73(4):410.e9-410.e15.

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: http://www.cms.gov/medicare-coverage-database/details/nca-decision-memo.aspx?NCAId=261. Accessed on August 7, 2023.
2. NCCN Clinical Practice Guidelines in Oncology ^© 2023. National Comprehensive Cancer Network, Inc. For additional information visit the NCCN website: http://www.nccn.org/index.asp. Accessed on August 7, 2023.
   • Anal Carcinoma V2.2023). Revised April, 28, 2023.
   • Central Nervous System (V1.2023). Revised March 24, 2023.
   • Hodgkin Lymphoma (V2.2023). Revised November 8, 2022.
   • Neuroendocrine and Adrenal Tumors (V2.2022). Revised December 21, 2022.
   • Occult Primary (V3.2023). Revised December 21, 2022.
   • Ovarian Cancer Including Fallopian Tube Cancer and Primary Peritoneal Cancer. (V2.2023). Revised June 2, 2023.
   • Pediatric Hodgkin Lymphoma (V2.2023). Revised March 9, 2023.
   • Pediatric Aggressive Mature B-Cell Lymphomas (V1.2023). Revised April 4, 2023.
   • Prostate Cancer (V1.2023). Revised September 16, 2022.

mpMRI, Multiparametric Magnetic Resonance Imaging
3D-THRIVE, Three-dimensional T1-weighted High-resolution Isotropic Volume Examination
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.