Dr. Rupal Jain is back with Episode 2 of The Rad Review: The ABCT’s of CT Imaging (Part II)
Pearl #1: The Hounsfield unit of blood is approximately 50.
Pearl #2: CT Angiography (CTA) is not the same as CT with IV Contrast. CTA is a special type of CT with IV contrast study that requires power injection of contrast so that the contrast is specifically timed for the arterial phase.
Pearl #3: In order to obtain a CTA, where contrast is caught quickly in the arterial phase, the patient is going to need a power-injectable line in which contrast can be pushed at a faster rate of approximately 4-5mL/min. Examples of power-injectable lines include: 20G peripheral IV in the antecubital fossa and certain PICC lines/central lines/chest ports. If you’re not sure if the PICC/central line is power injectable, check the lumen or the hub for the words “power injectable”, “CT” or “5 mL/min”. If the patient has a chest port, consider checking the operative report to see what type of line was placed and then check the manufacturer’s guidelines. If you don’t know what type of chest port the patient has, zoom into the chest x-ray in order to look for the letters “CT,” which would confirm that the chest port is indeed power-injectable.
- Coche E, Pawlak S, Dechambre S, Maldague B. Peripheral pulmonary arteries: identification at multislice helical CT with 3D reconstruction. Eur Radiol 2003; 13:815-822
- Bae KT. Peak contrast enhancement in CT and MR angiography: when does it occur and why? Pharmacokinetic study in a porcine model. Radiology 2003; 227:809-816
- University of California San Francisco Department of Radiology and Biomedical Imaging. Vascular Access and Use of Central Lines and Ports in Adults. Retrieved from https://radiology.ucsf.edu/patient-care/patient-safety/contrast/iodinated/vascular-access-adults
- Alexander MD, Morrison HL. Power-injectable ports: safety during placement, therapeutic use, and contrast administration during computed tomography procedures. J Vasc Access. 2012;13(4):432-437. doi:10.5301/jva.5000074