title: Validation of a raw data-based synchronization signal (kymogram) for phase-correlated cardiac image reconstruction.
abstract: Phase-correlated reconstruction is commonly used in computed tomography (CT)-based cardiac imaging. Alternatively to the commonly used ECG, the raw data-based kymogram function can be used as a synchronization signal. We used raw data of 100 consecutive patient exams to compare the performance of kymogram function to the ECG signal. For objective validation the correlation of the ECG and the kymogram was assessed. Additionally, we performed a double-blinded comparison of ECG-based and kymogram-based phase-correlated images. The two synchronization signals showed good correlation indicated by a mean difference in the detected heart rate of negligible 0.2 bpm. The mean image quality score was 2.0 points for kymogram-correlated images and 2.3 points for ECG-correlated images, respectively (3: best; 0: worst). The kymogram and the ECG provided images adequate for diagnosis for 93 and 97 patients, respectively. For 50% of the datasets the kymogram provided an equivalent or even higher image quality compared with the ECG signal. We conclude that an acceptable image quality can be assured in most cases by the kymogram. Improvements of image quality by the kymogram function were observed in a noticeable number of cases. The kymogram can serve as a backup solution when an ECG is not available or lacking in quality.
authors.affiliation: Institute of Medical Physics (IMP), University of Erlangen-Nürnberg, Henkestrasse 91, 91052 Erlangen, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Ertel
authors.forename: Tobias
authors.initials: T
authors.lastname: Pflederer
authors.forename: Stephan
authors.initials: S
authors.lastname: Achenbach
authors.forename: Marc
authors.initials: M
authors.lastname: Kachelriess
authors.forename: Peter
authors.initials: P
authors.lastname: Steffen
authors.forename: Willi A
authors.initials: WA
authors.lastname: Kalender
mesh_terms: D003324:Coronary Artery Disease / Q000175:diagnosis*; D004311:Double-Blind Method; D004562:Electrocardiography / Q000706:statistics & numerical data; D004571:Electrokymography / Q000379:methods / Q000706:statistics & numerical data; D006321:Heart / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006331:Heart Diseases / Q000175:diagnosis; D006339:Heart Rate; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007734:Kymography / Q000379:methods* / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D036542:Tomography, Spiral Computed / Q000295:instrumentation / Q000379:methods*