Reduction of radiation exposure and improvement of image quality with BMI-adapted prospective cardiac computed tomography and iterative reconstruction

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• 作者：Waldemar Hosch ; Wolfram Stiller ; Dirk Mueller ; Gitsios Gitsioudis ; Johanna Welzel ; Monika Dadrich ; Sebastian J. Buss ; Evangelos Giannitsis ; Hans U. Kauczor ; Hugo A. Katus ; Grigorios Korosoglou
• 关键词：256-Slice computed tomography angiography ; Image quality ; Radiation exposure ; Prospective ECG-triggering ; Iterative reconstruction
• 刊名：European Journal of Radiology
• 出版年：2012
• 出版时间：November, 2012
• 年：2012
• 卷：81
• 期：11
• 页码：3568-3576
• 全文大小：1314 K

文摘

Purpose

To assess the impact of body mass index (BMI)-adapted protocols and iterative reconstruction algorithms (iDose) on patient radiation exposure and image quality in patients undergoing prospective ECG-triggered 256-slice coronary computed tomography angiography (CCTA).

Methods

Image quality and radiation exposure were systematically analyzed in 100 patients. 60 Patients underwent prospective ECG-triggered CCTA using a non-tailored protocol and served as a ¡®control¡¯ group (Group 1: 120 kV, 200 mA s). 40 Consecutive patients with suspected coronary artery disease (CAD) underwent prospective CCTA, using BMI-adapted tube voltage and standard (Group 2: 100/120 kV, 100-200 mA s) versus reduced tube current (Group 3: 100/120 kV, 75-150 mA s). Iterative reconstructions were provided with different iDose levels and were compared to filtered back projection (FBP) reconstructions. Image quality was assessed in consensus of 2 experienced observers and using a 5-grade scale (1 = best to 5 = worse), and signal- and contrast-to-noise ratios (SNR and CNR) were quantified.

Results

CCTA was performed without adverse events in all patients (n = 100, heart rate of 47-87 bpm and BMI of 19-38 kg/m²). Patients examined using the non-tailored protocol in Group 1 had the highest radiation exposure (3.2 ¡À 0.4 mSv), followed by Group 2 (1.7 ¡À 0.7 mSv) and Group 3 (1.2 ¡À 0.6 mSv) (radiation savings of 47 % and 63 % , respectively, p < 0.001). Iterative reconstructions provided increased SNR and CNR, particularly when higher iDose level 5 was applied with Multi-Frequency reconstruction (iDose5 MFR) (14.1 ¡À 4.6 versus 21.2 ¡À 7.3 for SNR and 12.0 ¡À 4.2 versus 18.1 ¡À 6.6 for CNR, for FBP versus iDose5 MFR, respectively, p < 0.001). The combination of BMI adaptation with iterative reconstruction reduced radiation exposure and simultaneously improved image quality (subjective image quality of 1.4 ¡À 0.4 versus 1.9 ¡À 0.5 for Group 2 reconstructed using iDose5 MFR versus Group 1 reconstructed using FBP, p < 0.05).

Conclusions

Prospective ECG-triggered 256-slice CCTA allows for visualization of the coronary artery tree with high image quality within a wide range of heart rates and BMIs. The combination of BMI-adapted protocols with iterative reconstruction algorithms can reduce radiation exposure for the patients and simultaneously improve image quality.