Evaluation of 18F-FDG PET and MRI in differentiating benign and malignant peripheral nerve sheath tumors

Stephen M. Broski, Geoffrey B. Johnson, Benjamin M. Howe, Mark A. Nathan, Doris E. Wenger, Robert J. Spinner, Kimberly K. Amrami

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


Objective: To compare 18F-FDG PET/CT and MRI for differentiating benign and malignant peripheral nerve sheath tumors (BPNSTs and MPNSTs) and correlate imaging characteristics with histopathology. Materials and methods: Patients with pathologically proven PNSTs undergoing 18F-FDG PET/CT were retrospectively reviewed. PET/CTs and, if available, MRIs were analyzed, noting multiple imaging characteristics and likely pathology (benign or malignant). Results: Thirty-eight patients with 23 BPNSTs and 20 MPNSTs were analyzed. MPNSTs had higher SUVmax (10.1 ± 1.0, 4.2 ± 0.4, p < 0.0001), metabolic tumor volume (146.5 ± 39.4, 21.7 ± 6.6 cm3, p = 0.01), total lesion glycolysis (640.7 ± 177.5, 89.9 ± 23.2 cm3*g/ml, p = 0.01), and SUVmax/LiverSUVmean (5.3 ± 0.5, 2.0 ± 0.2, p < 0.0001). All lesions with SUVmax < 4.3 were benign. All lesions with SUVmax > 8.1 were malignant. SUVmax cutoff of 6.1 yielded 90.0 % sensitivity and 78.3 % specificity for MPNSTs. SUVmax/LiverSUVmean cutoff of 3.0 yielded 90.0 % sensitivity and 82.6 % specificity. MPNSTs more commonly had heterogeneous FDG activity (p < 0.0001), perilesional edema (p = 0.004), cystic degeneration/necrosis (p = 0.015), and irregular margins (p = 0.004). There was no difference in lesion size, MRI signal characteristics, or enhancement. Expertly interpreted MRI had 62.5–81.3 % sensitivity and 94.1–100.0 % specificity while PET had 90.0–100.0 % sensitivity and 52.2–82.6 % specificity for diagnosing MPNSTs. Conclusions: FDG PET and MRI play a complementary role in PNST evaluation. Multiple metabolic parameters and MRI imaging characteristics are useful in differentiating BPNSTs from MPNSTs. This underscores the potential critical role of PET/MRI in these patients.

Original languageEnglish (US)
Pages (from-to)1097-1105
Number of pages9
JournalSkeletal Radiology
Issue number8
StatePublished - Aug 1 2016


  • MRI
  • Nerve sheath
  • PET/CT
  • Tumor

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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