From the Research
Computed Tomography Angiography (CTA) can detect active bleeding at rates of less than 0.1 mL/min, as demonstrated by a recent study 1. This detection threshold allows CTA to identify bleeding that is clinically significant while being fast enough to guide urgent treatment decisions. CTA works by capturing images during the arterial phase of contrast administration, typically 20-30 seconds after contrast injection, when the contrast material is primarily in the arterial system. For optimal bleeding detection, multiphasic CTA protocols are often used, including arterial, venous, and delayed phases to capture intermittent bleeding that might be missed on single-phase imaging. Some key points to consider when using CTA for bleeding detection include:
- The technology's ability to detect bleeding depends on several factors including the scanner technology (with newer multidetector CT scanners offering improved sensitivity), contrast protocol used, patient factors such as cardiac output, and the anatomical location of the bleeding.
- CTA's rapid acquisition time of just seconds to minutes makes it particularly valuable in emergency settings where quick diagnosis is essential for patient survival.
- A study from 2021 found that larger extravasation volumes correlate with higher bleeding rates and may identify patients who require hemostatic therapy, have intraprocedural bleeding, and require blood transfusions 1.
- Another study from 2021 highlighted the underutilization of CTA in the management of gastrointestinal bleeding, despite its high sensitivity and specificity for diagnosis and treatment 2. Overall, CTA is a highly sensitive and valuable tool for detecting active bleeding, and its use should be considered in emergency settings where quick diagnosis is essential for patient survival.