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Minerva Medica 2011 August;102(4):249-59


language: English

Radiation dose in coronary artery angiography with 320-detector row CT and its diagnostic accuracy: comparison with 64-detector row CT

Zhang T., Luo Z. R., Wang D., Han D., Bai J. Q., Meng X. W., Shen B. Z.

Department of Radiology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin, China


AIM:The aim of this study was the comparison of image quality, diagnostic accuracy and radiation dose of ECG-gated volume scan mode of 320-detector row CT with 64-detector row CT.
METHODS: A hundred and twenty patients receiving coronary artery CT angiography (CTA) were divided into two groups. Sixty patients in Group A underwent 64-detector row CTA; for the remainder, Group B, 320-detector row CT was used. Conventional coronary angiography was then performed in all patients. In Group B, patients with a pulse <65 beat/min underwent a prospective ECG-gated volume scan using a 70-80% R-R phase window and 1-beat, whereas a 30-80% R-R phase window, 2-beat CT was performed in patients with a pulse >65 beat/min.
RESULTS: In Group A, 247 vessels and 920 segments were assessed; in Group B, 242 and 906. In 320-detector row CTA, the coronary stenosis diagnosis’ specificities were 98%, 96%, and 95% at the segmental, vessel, and patient levels, respectively (98%, 94%, and 92% in 64-detector row CTA); the negative predictive values were 99%, 98%, and 100% (98%, 97%, and 95% in 64-detector row CTA). There was no significant difference in specificity or negative predictive values between the groups. The average effective radiation dose in Group B was lower than in Group A (P<0.001). In Group B, the dose for 48 patients with 70-80% R-R phase window, 1-beat scan, was lower than for the remaining 12 patients (30-80% R-R phase window, 2-beat) (P<0.001).
CONCLUSION: The 320-detector CT reduces the radiation exposure by approximately 80% compared with 64-detector CT, with similar diagnostic accuracy and image quality.

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