Rapid echoplanar diffusion imaging in a case of variant Creutzfeldt-Jakob disease; where speed is of the essence

Neuroimaging with magnetic resonance imaging (MRI) is important in the diagnosis of Creutzfeldt-Jakob disease (CJD), but is frequently frustrated by patient movement. Diffusion-weighted imaging (DWI) has previously shown markedly restricted diffusion in grey matter structures of patients with CJD, and may add to diagnostic sensitivity. Echoplanar imaging (EPI) sequences, which are usually used for DWI, are also very rapid, and typically allow imaging of the whole brain in less than 1 min. A case of histologically proven variant CJD (vCJD) in which conventional MRI was difficult to interpret confidently owing to motion artefact, but EPI was diagnostic, emphasises the utility of rapid imaging in agitated patients. Comparison of the regional quantitative apparent diffusion coefficient (ADC) with a control group (n=5) showed restricted diffusion in the caudate (vCJD: 0.63×10⁻³ mm²/s; controls: mean 0.722×10⁻³ mm²/s, SD 0.017) and lentiform (vCJD: 0.65×10⁻³ mm²/s; controls: mean 0.707×10⁻³ mm²/s, SD 0.011) nuclei. T2 effects dominated the signal abnormality on DWI in the pulvinar; ADC was increased (vCJD: 0.87–0.95×10⁻³ mm²/s; controls: mean 0.773×10⁻³ mm²/s, SD 0.038). Our data emphasise variation in diffusion patterns in vCJD, and illustrate the value in using all the components available from the DWI examination for maximum diagnostic information. EPI-DWI provides both rapid T2- and diffusion-dependent information, and is recommended for those patients in whom confusion and agitation is likely to confound standard MRI protocols.