CT-angiography in acute bleeding: Is a non-enhanced scan necessary?

OBJECTIVE: In clinical routine CT-angiography is frequently used to detect hemorrhage and to locate its source. Many centers use a triple phase protocol consisting of non-contrast, arterial and portal venous phase scan. The aim of this study was to clarify the added value of the non-contrast CT scan in detection of hemorrhage and to provide evidence for or against its usage. MATERIALS & METHODS: We retrospectively included all patients between 2014 and 2020 who underwent triphasic CT angiography for suspected bleeding and interventional angiography within 6 h of CT confirming bleeding. Two experienced observers re-evaluated all CT scans and established consensus on whether the bleeding could confidently be detected without the non-enhanced CT scan. Additionally, we recorded data on radiation exposure. RESULTS: 915.0 mGy*cm). CONCLUSION: Our results suggest that in the vast majority of cases non-contrast CT is not necessary to detect hemorrhage. Omission of non-enhanced CT scans results in relevant dose reduction. However, in few cases non-contrast scan can be helpful to exclude false positive findings in particular in suspected gastrointestinal bleeding.