Role of diffusion- and perfusion-weighted MR imaging for brain tumour characterisation Impiego delle tecniche di diffusione e di perfusione con RM nella caratterizzazione dei tumori cerebrali

Purpose. This study was undertaken to correlate apparent diffusion coefficient (ADC) and relative regional cerebral blood volume (rrCBV) to histological findings in a large series of patients with primary or secondary brain tumours to evaluate diffusion-weighted (DWI) and perfusionweighted (PWI) imaging in the characterisation of cerebral tumors. Materials and methods. Ninety-eight patients with cerebral tumours, 46 of which were primary (seven grade 0-I, nine low-grade gliomas, two gliomatosis cerebri, nine lymphomas and 19 high-grade gliomas) and 52 secondary, underwent conventional magnetic resonance (MR) imaging completed with DWI and dynamic contrast susceptibility PWI. Both ADC and rrCBV were calculated on a workstation by using Functool 2 software. Student’s t test was used to determine any statistically significant differences in the ADC and rrCBV values. Results. Seventeen of 98 tumours were cystic or necrotic (12/17 hypointense and 5/17 hyperintense on DWI); the ADC value of hyperintense cystic areas was 0.97±0.23×10 -3 mm 2 /s. The ADC value of solid tumours varied between 0.64 and 3.5×10 -3 mm 2 /s. The rrCBV value was 1.4 (σ 0.66) in low-grade gliomas; 1.22 (σ 0.25) in lymphomas; 4.5 (σ 0.85) in grade III gliomas; 3.18 (σ 1.26) in grade IV gliomas and 2.53 (σ 1.6) in metastases.