Differentiation of pilocytic astrocytoma, medulloblastoma, and hemangioblastoma on diffusion-weighted and dynamic susceptibility contrast perfusion MRI

This study aimed to evaluate the diagnostic performance of dynamic susceptibility contrast (DSC) perfusion magnetic resonance imaging and apparent diffusion coefficient (ADC) for differentiating common posterior fossa tumors, pilocytic astrocytoma (PA), medulloblastoma (MB), and hemangioblastoma (HB). Between January 2016 and April 2022, we enrolled 23 (median age, 7 years [range, 2–26]; 12 female), 13 (10 years [1–24]; 3 female), and 12 (43 years [23–73]; 7 female) patients with PA, MB, and HB, respectively. Normalized relative cerebral blood volume and flow (nrCBV and nrCBF) and normalized mean ADC (nADCmean) were calculated from volume-of-interest and statistically compared. nADCmean was significantly higher in PA than in MB (PA: median, 2.2 [range, 1.59–2.65] vs MB: 0.93 [0.70–1.37], P < .001). nrCBF was significantly higher in HB than in PA and MB (PA: 1.10 [0.54–2.26] vs MB: 1.62 [0.93–3.16] vs HB: 7.83 [2.75–20.1], all P < .001). nrCBV was significantly different between all 3 tumor types (PA: 0.89 [0.34–2.28] vs MB: 1.69 [0.93–4.23] vs HB: 8.48 [4.59–16.3], P = .008 for PA vs MB; P < .001 for PA vs HB and MB vs HB). All tumors were successfully differentiated using an algorithmic approach with a threshold value of 4.58 for nrCBV and subsequent threshold value of 1.38 for nADCmean. DSC parameters and nADCmean were significantly different between PA, MB, and HB. An algorithmic approach combining nrCBV and nADCmean may be useful for differentiating these tumor types.