Validation of a raw data-based synchronization signal (kymogram) for phase-correlated cardiac image reconstruction
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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.
KeywordsSpiral CT Cardiac imaging ECG Kymogram Heart motion
We are grateful to the CT division of Siemens Medical Solutions for financial support of this study. We also wish to acknowledge Katja Scholz for her assistance with the statistical analysis tools.
- 4.Flohr T, Prokop M, Becker C, Schoepf UJ, Kopp AF, White RD, Schaller S, Ohnesorge B (2002) A retrospectively ECG-gated multislice spiral CT scan and reconstruction technique with supression of heart pulsation artifacts for cardio-thoratic imaging with extended volume coverage. Eur Radiol 12(6):1497–1503PubMedCrossRefGoogle Scholar
- 6.Willi A, Kalender WA, Kachelrieß M (1999) Computertomograph mit objektbezogener Bewegungsartefaktreduktion und Extraktion der Objektbewegungsinformation (Kymogramm). European Patent Office, Patent pending, Patent No.: 99111708.6–1522Google Scholar
- 10.Ertel D, Kachelrieß M, Pflederer T, Achenbach S, Lapp RM, Nagel M, Kalender WA (2006) Rawdata-based detection of the optimal reconstruction phase in ECG-gated cardiac image reconstruction. Proc MICCAI LNCS 4191:348–355Google Scholar
- 11.Ertel D (2007) Kymogram-based cardiac CT image reconstruction. In: Kalender WA (ed) Berichte aus dem Institut für Medizinische Physik. Shaker, AachenGoogle Scholar