title: Computed Tomography Angiography of Carotid Arteries and Vertebrobasilar System: A Simulation Study for Radiation Dose Reduction.
abstract: Computed tomography angiography (CTA) of carotid arteries and vertebrobasilar system is a standardized procedure with excellent image quality, but radiation exposure remains a matter of concern. The aim of this study is to examine to what extent radiation dose can be lowered in relation to a standard protocol by simulating examinations with lower tube currents applying a dedicated software.Lower tube current was simulated by a dedicated noise insertion and reconstruction software (ReconCT). In a phantom study, true scans were performed with different dose protocols and compared to the results of simulated dose reductions of the same degree, respectively. In a patient study, 30 CTAs of supra-aortic vessels were reconstructed at a level of 100%, 75%, 50%, and 25% of the initial dose. Objective and subjective image analyses were performed.No significant noise differences between true scans and simulated scans of mimicked contrasted vessels were found. In the patient study, the quality scores of the 4 dose groups differed statistically significant; this difference vanished for the comparison of the 100% and 75% datasets after dichotomization into the categories of diagnostic and nondiagnostic image quality (P = .50).This study suggests an easy-to-implement method of simulating CTAs of carotid arteries and vertebrobasilar system with lower tube current for dose reduction by artificially adding noise to the original raw data. Lowering the radiation dose in a moderate extent to 75% of the original dose levels does not significantly alter the diagnostic image quality.
authors.affiliation: From the Institute of Radiology (MK, SE, AE, FK, MSM, JFB, MU, MML), University of Erlangen-Nuremberg, Maximiliansplatz 1, Erlangen, Germany; and Siemens Healthcare (TA), Forchheim, Germany. MK and SE contributed equally to this work.
authors.forename: Manuel
authors.initials: M
authors.lastname: Kramer
authors.forename: Stephan
authors.initials: S
authors.lastname: Ellmann
authors.forename: Thomas
authors.initials: T
authors.lastname: Allmendinger
authors.forename: Achim
authors.initials: A
authors.lastname: Eller
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Kammerer
authors.forename: Matthias S
authors.initials: MS
authors.lastname: May
authors.forename: João F
authors.initials: JF
authors.lastname: Baigger
authors.forename: Michael
authors.initials: M
authors.lastname: Uder
authors.forename: Michael M
authors.initials: MM
authors.lastname: Lell
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000792:Angiography; D001488:Basilar Artery / Q000000981:diagnostic imaging; D001921:Brain / Q000098:blood supply; D002339:Carotid Arteries / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D058996:Quality Improvement; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed; D014711:Vertebral Artery / Q000000981:diagnostic imaging*