Clinical Value of Multiparametric Whole-Body Magnetic Resonance Imaging over Whole-Spine Magnetic Resonance Imaging in Patients with Neurofibromatosis Type I

Objective To determine the clinical value of multiparametric whole-body (WBMRI) over whole-spine magnetic resonance imaging (WSMRI) in patients with neurofibromatosis type 1 (NF1). Methods A consecutive series of 30 patients with known NF1 underwent WBMRI screening using anatomic, diffusion, and contrast imaging over a 30-month period. Thirteen of 30 patients also had WSMRI. Tumors were classified per location and morphology and were software segmented to determine numbers and volumes. Extra tumor burden detected by WBMRI was assessed. The comparison was made between WBMRI and WSMRI in 13 patients who had both types of scans. Enhancement characteristics were noted and 2 readers recorded apparent diffusion coefficient (ADC) in 30 patients with WBMRI scans. Interobserver performance was assessed using intraclass correlations. A 2-sample test was used for testing mean differences between tumors. Results The age of 30 patients with WBMRI and 13 patients with WSMRI were 39.4 ± 14.4 and 41.54 ± 10.79 years (mean ± standard deviation) and male/female ratio was 1:1.73 and 1:2.25, respectively. Only 1 patient was found to have a heterogeneously enhancing lumbar paraspinal malignant peripheral nerve sheath tumor, seen on both WBMRI and WSMRI. The additional total number of tumors on WBMRI was 2766 and 2602 tumors were missed on WSMRI. The volume of tumors was 16,053 cm³ and 15,614 cm³ of tumor burden was incrementally detected on WBMRI. Mean ADC of superficial tumors was significantly lower than that of deep tumors (1.93 ± 0.39 × 10⁻³ mm²/second and 2.26 ± 0.56 × 10⁻³ mm²/second, respectively; P = 0.009), whereas no ADC differences were seen in plexiform versus discrete tumors (P = 0.64). Interobserver performance for ADC was excellent (intraclass correlation, 0.84). Conclusions Multiparametric WBMRI provides superior determination of tumor burden and should be considered as a preferred method for evaluation of patients with NF1.