Work

Discrimination of benign, atypical, and malignant peripheral nerve sheath tumours in neurofibromatosis type 1 – intraindividual comparison of positron emission computed tomography and diffusion-weighted magnetic resonance imaging

Year: 2024

Type: article

Abstract: Background To intraindividually compare the diagnostic performance of positron emission computed tomography (F-18-FDG-PET/CT) and diffusion-weighted magnetic resonance imaging (DW-MRI) in a non-inferiority design for the discrimination of peripheral nerve sheath tumours as benign (BPNST), atypical (ANF), or malignant (MPNST) in patients with neurofibromatosis type 1 (NF1). Results In this prospective single-centre study, thirty-four NF1 patients (18 male; 30 ± 11 years) underwent F-18-FDG-PET/CT and multi-b-value DW-MRI (11 b-values 0 – 800 s/mm²) at 3T. Sixty-six lesions corresponding to 39 BPNST, 11 ANF, and 16 MPNST were evaluated. Two radiologists independently assessed the maximum standardized uptake value (SUV max ) and mean and minimum apparent diffusion coefficient (ADC mean/min ) as well as the ADC in areas of lowest signal intensity in each lesion (ADC dark ). The AUCs of DW-MRI and F-18-FDG-PET/CT were compared to determine whether the ADC is non-inferior to SUV max (non-inferiority margin equal to -10%). Follow-up of ≥ 24 months (BPNST) or histopathological evaluation (MPNST + ANF) served as diagnostic reference standard. Both SUV max and ADC parameters demonstrated good diagnostic accuracy (AUC SUVmax 94.0%; AUC ADCmean/min/dark 91.6% / 90.1% / 92.5%). However, non-inferiority could not be demonstrated for any of the three ADC parameters (lower limits of the confidence intervals of the difference between the AUC of ADC mean/min/dark and SUV max -12.9% / -14.5% / -11.6%). Inter-rater reliability was excellent for both imaging techniques (Krippendorff’s alpha all > 0.94). Conclusions Both PET/CT-derived SUV max and MRI-derived ADC allow sensitive and non-invasive differentiation of benign and (pre)-malignant peripheral nerve sheath tumours. Nevertheless, DW-MRI cannot be considered as non-inferior to F-18-FDG-PET/CT in this prospective single-centre study.

Source: EJNMMI Research

DOI: 10.1186/s13550-024-01189-0