Laboratory and imaging studies for the diagnosis of prion disease

We evaluated the diagnostic sensitivity of periodic synchronous discharge (PSD) in EEG, brain specific proteins in CSF such as neuron specific enolase (NSE), 14-3-3 protein, and tau protein, and imaging studies performed by T2-weighted MRI (T2I) and diffusion-weighted MRI (DWI). 36 patients with a mean age of 68.6 years were enrolled. Their diagnostic levels were as follows: seven were definite, 28 were possible, and one was probable who had a disease-specific point mutation of V180I. The diagnostic sensitivities of PSD, NSE, 14-3-3 protein, tau protein, DWI, and T2I were 50% (N = 36), 70% (N = 30), 80.8% (N = 26), 87.5% (N = 16), 92.3% (N = 26), and 42.3% (N = 26), respectively. DWI could revealed the CJD-related lesions earlier than the appearance of PSD. DWI revealed the lesions even in the patients who did not show PSD. For the diagnosis of CJD, DWI and either 14-3-3 protein or tau protein are useful. Using western blot, we detected the protease-resistant PrP in the urine of 11 of 15 CJD patients. We also detected it in three of 25 disease control patients. Differing from previous reports, the detection of a proterase-resistant PrP was not specific to CJD patients. However, the sensitivity was 73.3% and the specificity was 88.9%.