David Amstutz MD, PRESENTER: Nothing to Disclose

Abstract: HTML Purpose: To compare the adequacy of cerebral arterial enhancement achieved with computed tomographic angiography (CTA) protocols employing dual-chamber (contrast-saline chaser) and single-chamber (contrast only) power injectors. Methods and Materials: Over a four week span at our institution, CT angiography of the brain was performed in 42 patients. In twenty-two patients, a 50 cc Omnipaque-300 contrast bolus was injected and chased with a 40 cc saline flush using a dual-chamber power injector (Medrad, Inc; Indianola, PA). In twenty patients, a 75 cc Omnipaque-300 contrast bolus was injected through a standard single chamber power injector (Medrad Inc, Indianola, PA). Attenuation values (measured as Hounsfield units (HU)) within in the A2 segment of the anterior cerebral artery, V4 segment of the vertebral artery, and M1 segment of the middle cerebral artery were measured. Comparisons between protocols were performed using a t-test. Attenuation values within the frontal lobe white matter were used as an internal standard between examinations. Adequacy of bolus timing and venous contamination were also graded and compared. Results: Bolus timing was considered adequate in 21 of the 22 dual injector exams and 18 of the 20 single injector exams. Of the exams with an appropriately timed contrast bolus, venous contamination was observed in 1 of 21 dual injector exams and 2 of 18 single injector exams. The mean attenuation values measured within the ACA were significantly less with the dual injector protocol (144 HU dual, 189 HU single; p < 0.05) than with the single injector protocol. No differences in attenuation values were observed between protocols within the MCA (288 HU dual, 323 HU single, p = 0.58) or vertebral artery (199 HU dual, 170 HU single, p = 0.37). Although the absolute level of ACA opacification was less with the dual injector protocol, the minimum level of arterial opacification required for diagnostic evaluation (HU > 90) was achieved in 20 of 21 cases. Similarly, in 17 of 18 cases using the single injector, the level of ACA opacification met or exceeded the level required for diagnostic evaluation. Conclusion: The use of a dual injector with a contrast-saline chaser protocol for cerebral CT angiography provides similar levels of arterial enhancement, rates of venous contamination, and bolus timing accuracy when compared with a standard single injector protocol. The dual phase injector uses 25 cc less contrast per exam which translates into decreased patient risk (e.g., contrast induced nephropathy) and reduced technical cost per exam.       Questions about this event email: Stutz5150@aol.com

Amstutz MD, D, Utility of a Dual Power Injector for Intracranial Computed Tomographic Angiography (CTA).  Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL. http://archive.rsna.org/2003/3103914.html