title: Improved aortic enhancement in CT angiography using slope-based triggering with table speed optimization: a pilot study.
abstract: To assess whether a scan triggering technique based on the slope of the time-attenuation curve combined with table speed optimization may improve arterial enhancement in aortic CT angiography compared to conventional threshold-based triggering techniques. Measurements of arterial enhancement were performed in a physiologic flow phantom over a range of simulated cardiac outputs (2.2-8.1 L/min) using contrast media boluses of 80 and 150 mL injected at 4 mL/s. These measurements were used to construct computer models of aortic attenuation in CT angiography, using cardiac output, aortic diameter, and CT table speed as input parameters. In-plane enhancement was calculated for normal and aneurysmal aortic diameters. Calculated arterial enhancement was poor (<150 HU) along most of the scan length using the threshold-based triggering technique for low cardiac outputs and the aneurysmal aorta model. Implementation of the slope-based triggering technique with table speed optimization improved enhancement in all scenarios and yielded good- (>200 HU; 13/16 scenarios) to excellent-quality (>300 HU; 3/16 scenarios) enhancement in all cases. Slope-based triggering with table speed optimization may improve the technical quality of aortic CT angiography over conventional threshold-based techniques, and may reduce technical failures related to low cardiac output and slow flow through an aneurysmal aorta.
authors: Department of Radiology, Duke University Medical Center, Duke North, Room 1508F, Erwin Road, Durham, NC 27710, USA. mustafa.bashir@duke.edu
authors: Mustafa R
authors: MR
authors: Bashir
authors: Paul W
authors: PW
authors: Weber
authors: Daniela B
authors: DB
authors: Husarik
authors: Laurens E
authors: LE
authors: Howle
authors: Rendon C
authors: RC
authors: Nelson
mesh_terms: D000465:Algorithms; D001014:Aortic Aneurysm / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001027:Aortography / Q000295:instrumentation / Q000379:methods*; D001783:Blood Flow Velocity; D002302:Cardiac Output; D003198:Computer Simulation; D003287:Contrast Media; D006801:Humans; D016014:Linear Models; D008955:Models, Cardiovascular; D061330:Multidetector Computed Tomography / Q000295:instrumentation; D019047:Phantoms, Imaging; D010865:Pilot Projects; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D012039:Regional Blood Flow; D013997:Time Factors
chemical_list: D003287:Contrast Media