Displaced cortical vein sign on CT in infants: a reliable predictor to distinguish low-attenuation subdural collections from benign enlargement of subarachnoid spaces.

Abstract

Differentiating benign enlargement of subarachnoid spaces (BESS) from low-attenuation subdural collections on CT imaging of infants can be challenging. This distinction is crucial in infants, as subdural collections may raise the concern for abusive head trauma (AHT). To evaluate the utilization of the displaced cortical vein sign on CT as a predictor of pathological subdural collections confirmed by MRI and to assess the reproducibility of this finding among radiologists with different levels of clinical experience. A total of 104 imaging exams were independently reviewed by junior- and senior-level radiologists (52 head CTs and 52 corresponding brain MRI exams). These exams included 43 MRI-confirmed cases of subdural collections and 9 MRI-confirmed cases of BESS from patients aged 0-2 years. The presence of pathological collections and sulcal flattening, and the displaced cortical vein sign were recorded for both reviewers along with attenuation and signal characteristics of the collections. Confirmed diagnosis of AHT was determined by chart review. The sensitivity, specificity, and inter-observer reliability were analyzed between reviewers. The average patient age was 6.4 months with a median age of 4 months. The sensitivity values of the displaced cortical vein sign on CT for the presence of subdural collections were 69.6% and 79.0% for the two reviewers, respectively. The specificity of this finding was 100% for both reviewers, with no false negative cases. Interobserver reliability was the highest for the depiction of the displaced cortical vein sign on CT (κ=0.63, 95% CI 0.45-0.82) and MRI (κ=0.96, 95% CI 0.87-1.00). All cases where at least 1 reviewer noted the displaced cortical vein sign on CT and were later confirmed to be traumatic subdural collection on MRI were concluded to have high concern for AHT upon chart review. In total, 23.3% (11 out of 52) of cases confirmed to have subdural collections on MRI were found to have calvarial fractures associated with their presentation. The displaced cortical vein sign on head CT is a specific and reproducible finding associated with subdural collections. Our data suggest that this sign is a more reliable and readily identifiable indicator of pathological subdural collections compared to other traditional imaging findings, such as flattening of the cerebral sulci.