The putamen intensity gradient in CJD diagnosis

The deep grey matter structures of the brain have been reported to show MR hyperintensity in the sporadic form of Creutzfeldt-Jakob disease (sCJD), but the criteria for visual judgment of this are not well defined. We carried out a quantitative study of T2 weighted and proton density scans comparing 10 sCJD patients with 10 non-CJD dementia controls (NCD) and also with I I patients suffering from the new variant form of CID (vCJD). Scans were acquired in a clinical context and came from many hospitals. Absolute intensities varied widely and did not allow any useful discrimination. In all groups the putamen had a gradient of reducing, intensity from anterior to posterior on T2 scans. In both s- and v- CJD patients this gradient was increased. Sensitivity and specificity (S&S) for sCJD against NCD were 89%. The T2 and PD intensities of the putamen relative to the other grey matter structures studied were not useful for distinguishing between any of the patient groups. The ratio of putamen to frontal white matter T2 intensity was significantly increased in vCJD compared to NCD and also to sCJD, while sCJD and NCD were indistinguishable by this test. We conclude that: (1) in our preliminary study, the putamen gradient appears to be important diagnostically for sCJD; (2) intensities of deep grey matter structures vary systematically and intensity-based segmentation methods used in patients and normals should take account of this.