Apparent Diffusion Coefficient Measurements. A Reliable Tool for the Diagnosis of Creutzfeldt-Jakob Disease

Background and Purpose

Creutzfeldt-Jakob disease (CJD) is a rare, rapidly fatal neurodegenerative disorder. The gold standard test for a positive diagnosis of definite CJD is histopathological confirmation, usually post-mortem; however, an autopsy study is not always feasible in all health settings.

Materials and Methods

We performed a cross-sectional analysis of a retrospectively enrolled cohort of patients with suspected prion disease between 2008 and 2019. Only patients with complete medical histories who fulfilled a diagnostic checklist were enrolled. The magnetic resonance imaging (MRI) sequences (T2-FLAIR and DWI) were analyzed, and the apparent diffusion coefficients (ADCs) were calculated for five regions of interest (ROIs) in each cerebral hemisphere.

Results

In total, 72 MRI scans were post-processed. The series included 47 cases of CJD, including 25 genetic and 22 sporadic cases, in addition to 25 age-paired controls with non-prion encephalopathies. The neostriatum showed the most significant difference in ADC values (×10^–3 mm²/s) at 0.5946 in the left anterior putamen vs. 0.8644 in the control encephalopathies (p < 0.001; 95% confidence interval: 0.5751–0.6142 vs. 0.7812–0.9476), while the other ROIs also showed significant differences. The best cut-off value to differentiate CJD from other encephalopathies was identified as 0.65×10^–3 mm²/s, with no significant differences in this coefficient between sporadic and genetic cases.

Conclusions

Quantitative ADC measurements made in the basal ganglia seem to be the most useful ante-mortem diagnostic tool for differentiating CJD from non-prion encephalopathies when cerebrospinal fluid real-time quaking-induced conversion or other specific misfolded protein detection tests are inaccessible.