MRI findings are often missed in the diagnosis of Creutzfeldt-Jakob disease

Abstract

Background: Establishing a confident clinical diagnosis before an advanced stage of illness can be difficult in Creutzfeldt-Jakob disease (CJD) but unlike common causes of dementia, prion diseases can often be diagnosed by identifying characteristic MRI signal changes. However, it is not known how often CJD-associated MRI changes are identified at the initial imaging report, whether the most sensitive sequences are used, and what impact MRI-diagnosis has on prompt referral to clinical trial-like studies.

Methods: We reviewed the MRI scans of 103 patients with CJD referred to the National Prion Clinic since 2007 and reviewed the presence of CJD-associated changes, compared these findings with the formal report from the referring centre and reviewed the types of sequence performed.

Results: In sCJD we found CJD-associated MRI changes in 83 of 91 cases (91% sensitivity). However, the referring centres documented CJD-associated MRI changes in 43 of the sCJD cases (47% sensitivity). The most common region not documented by referring centres was the cortex (23 of 68 sCJD cases), but there was a statistically significant discrepancy in all regions (p<0.0001). Patients in whom MRI abnormalities were missed by the referring hospital were more advanced at the time of recruitment to a clinical trial-like study (p=0.03).

Conclusions: CJD-associated MRI changes are often not documented on the formal investigation report at the referring centre. This is important as delay makes enrolment to clinical trials futile because of highly advanced disease. If a diagnosis of CJD is suspected, even if the initial imaging is reported as normal, a specialist MRI review either by an experienced neuroradiologist or by a prion disease specialist unit could facilitate earlier diagnosis.

Figure 1

The MRI scans of 91 patients with sCJD were reviewed and compared with the corresponding report from the referring centre. The overall sensitivity of MRI scans found by the NPC was 91% compared with 47% from the referring centre (p<0.0001). The NPC found that 74% of cases had cortical high signal, 73% of cases had changes in the caudate, 59% of cases had changes in the putamen and 37% in the thalamus. The region that there was the most discrepancy between the two impressions was the cortex but there was a significant difference in all regions evaluated (p<0.0001).