The analysis of high-attenuating, extra-axial fluid collections after traumatic brain injuries, especially in older patients, remains a challenge. A standard, single-energy CT scan does not allow for discrimination between a real subdural hematoma and iodinated contrast that leaked into the subdural space and could ultimately be mistaken for a new hemorrhage in follow-up scans, with numerous clinical consequences, including unnecessary repeated head CTs.
Our intention was to evaluate the use of dual-energy CT (DECT) with derived virtual noncontrast and 190-keV virtual monochromatic images to improve the differentiation between a hemorrhage and iodine contrast leakage into the subdural space. We found that, among our patients, those with enhancing subdural effusions were significantly older (mean age of 69 years) and the incidence for contrast leakage was 13% for patients older than 50. The peak contrast accumulation in the subdural space was reached within 8 hours after the full-body admission scan and a complete washout of the contrast occurred after 38 hours.
DECT acquisitions of the head with 190-keV virtual monochromatic images have become the standard for our trauma patients and are now increasingly adopted in other institutions.