title: Image quality and radiation dose stratified by patient heart rate for coronary 64- and 320-MDCT angiography.
abstract: OBJECTIVE. The purpose of this study is to retrospectively measure and compare estimated radiation doses between consecutive patient cohorts who underwent coronary imaging CT with 64- and 320-MDCT scanners. MATERIALS AND METHODS. Subjects without arrhythmia (n = 4475) underwent imaging with 64-MDCT (n = 770) and 320-MDCT (n = 3705) scanners and were classified into one of five subgroups according to the patient heart rate and the image acquisition strategy. For all patients, image quality was subjectively evaluated using a 3-point scale. Estimated radiation dose and image quality were compared between subjects stratified by CT scanner and by subgroups imaged with each technology. RESULTS. For patients with a heart rate of 60 beats/min or less, the estimated radiation dose was halved (3.8 ± 2.0 vs 7.6 ± 2.6 mSv) when the 320-MDCT scanner (n = 2787) replaced the 64-MDCT scanner (n = 511). For the entire cohort, image quality score was significantly better (2.9 ± 0.4 vs 2.8 ± 0.5; p < 0.0001) and the effective dose was significantly lower (4.9 ± 3.3 vs 9.9 ± 5.4 mSv; p < 0.0001) for 320-MDCT scanners, compared with 64-MDCT scanners. CONCLUSION. Wide area-detector coronary CT angiography protocols have reduced radiation dose, with image quality maintained at the same level, compared with 64-MDCT technologies.
authors.affiliation: Department of Cardiology, Takase Clinic, 885-2 Minami-orui, Takasaki 370-0036, Japan. s-fujimo@tj8.so-net.ne.jp
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Fujimoto
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Matsutani
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kondo
authors.forename: Tomonari
authors.initials: T
authors.lastname: Sano
authors.forename: Kanako
authors.initials: K
authors.lastname: Kumamaru
authors.forename: Shinichi
authors.initials: S
authors.lastname: Takase
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Rybicki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D011829:Radiation Dosage; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media