Assessment of solid lesions of the temporal fossa with diffusion-weighted magnetic resonance imaging

The aim of this work was to assess solid lesions of the temporal fossa with diffusion-weighted magnetic resonance imaging (MRI). A retrospective analysis of diffusion-weighted MRI obtained for 33 patients with solid lesions of the temporal fossa was conducted. Fifteen of the patients were male and 18 were female, and their mean age was 39 years. The apparent diffusion coefficient (ADC) of solid lesions of the temporal fossa was calculated on two separate occasions by the same observer. The mean ADC values (x10(-3) mm(2)/s) of the two readings in cases of malignancy (0.98 +/- 0.17 and 0.95 +/- 0.13) were significantly different to those of benign lesions (1.32 +/- 0.24 and 1.28 +/- 0.21) (P = 0.001 and 0.001), with excellent intra-observer agreement (kappa = 0.937). The area under the receiver operating characteristic curve was 0.855. A threshold ADC of 1.23 x 10(-3) mm(2)/s was found to have an accuracy of 91%, with sensitivity of 94% and specificity of 85%, for differentiating malignancy of the temporal fossa from benign lesions. It is concluded that ADC is a non-invasive imaging parameter that is able to differentiate malignancy of the temporal fossa from benign lesions.