Figure 1. Sample images for case 1. (a) T₂ map; (b) magnetization transfer ratio (MTR) map; (c) pre-contrast 3D T₁ weighted image; (d) post-contrast 3D T₁ weighted image. T₂ map (e) and MTR map (f) are thresholded so that the total abnormality is seen within the red shading. Note that stereological test systems for point counting are overlain on the enhancing abnormality (d), T₂ total enhancing abnormality (e) and MTR total abnormality (f) with a uniform random position to obtain unbiased volume estimation. Each red cross (+) signifies one test point. Details of the calculation of tumour volume and precision are given in the text.