Radiology, Charité-Universitätsmedizin Berlin, Germany.
Rofo. 2020 Dec;192(12):1174-1182. doi: 10.1055/a-1150-7646. Epub 2020 Apr 16.
To retrospectively investigate the effectiveness of a novel 3-phase protocol for computed tomography (CT) before transcatheter aortic valve implantation/transcatheter aortic valve replacement (TAVI/TAVR) in terms of radiation dose and image quality.
A total of 107 nonrandomized patients (81 ± 7.4 years) scheduled for TAVI/TAVR underwent preprocedural CT on an 80-row CT scanner. 55 patients underwent a combined ECG-synchronized spiral scan of the chest and non-ECG-synchronized spiral scan of the abdomen/pelvis as recommended by the Society of Cardiovascular Computed Tomography (SCCT). 52 patients underwent an updated 3-phase variable helical pitch (vHP3) protocol combining a non-ECG-synchronized spiral scan of the upper thoracic aperture, followed by a prospective ECG-synchronized spiral scan of the heart, and a non-ECG-synchronized abdominal/pelvic spiral scan. The radiation dose was determined from an automatically generated protocol based on the CT dose index (CTDI). Objective image quality in terms of vessel attenuation and image noise was measured, and the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Subjective image quality was evaluated using a 4-point scale and compared for interrater agreement using Cohen's weighted kappa coefficient (κw). All data were compared and statistically analyzed.
Use of the novel 3-phase vHP3 protocol reduced the dose-length product (DLP) from 1256.58 ± 619.05 mGycm to 790.90 ± 238.15 mGycm, reducing the effective dose (E) from 21.36 ± 10.52 mSv to 13.44 ± 4.05 mSv and size-specific dose estimates (SSDE) from 20.85 ± 7.29 mGy to 13.84 ± 2.94 mGy (p < 0.001). There were no significant differences in objective and subjective image quality between the two protocols and between the two readers.
The novel 3-phase vHP3 protocol significantly reduces the radiation dose of preprocedural TAVI/TAVR CT without a loss of image quality.
· The use of a novel 3-phase protocol for preprocedural TAVI/TAVR CT reduces radiation dose by 37 % compared to a combined ECG-synchronized and non-ECG-synchronized spiral CT protocol.. · Objective image quality remains unaffected as image noise, SNR, and CNR did not differ significantly between the two protocols. The average attenuation of the aortic root and abdominal aorta exceeded 450 HU in both protocols.. · The average subjective image quality ratings were good to excellent for both protocols with almost perfect to substantial interrater agreement..
· Shnayien S, Bressem KK, Beetz NL et al. Radiation Dose Reduction in Preprocedural CT Imaging for TAVI/TAVR Using a Novel 3-Phase Protocol: A Single Institution's Experience. Fortschr Röntgenstr 2020; 192: 1174 - 1182.
回顾性研究一种新的三阶段协议在经导管主动脉瓣植入/经导管主动脉瓣置换（TAVI/TAVR）前 CT 中的有效性，从辐射剂量和图像质量方面进行评估。
共 107 名非随机患者（81±7.4 岁）在 80 排 CT 扫描仪上进行了术前 CT 检查。55 名患者按照心血管计算机断层扫描协会（SCCT）的建议进行了胸部 ECG 同步螺旋扫描和腹部/骨盆非 ECG 同步螺旋扫描。52 名患者采用了更新的三阶段可变螺距（vHP3）方案，包括非 ECG 同步的上胸部孔径螺旋扫描，然后进行前瞻性 ECG 同步的心脏螺旋扫描，以及非 ECG 同步的腹部/骨盆螺旋扫描。辐射剂量由基于 CT 剂量指数（CTDI）的自动生成协议确定。对血管衰减和图像噪声的客观图像质量进行了测量，并计算了信噪比（SNR）和对比噪声比（CNR）。使用 4 分制对主观图像质量进行评估，并使用 Cohen 加权 kappa 系数（κw）比较了观察者间的一致性。比较并对所有数据进行了统计学分析。
使用新型三阶段 vHP3 方案，剂量长度乘积（DLP）从 1256.58±619.05 mGycm 降低到 790.90±238.15 mGycm，有效剂量（E）从 21.36±10.52 mSv 降低到 13.44±4.05 mSv，体积剂量估计值（SSDE）从 20.85±7.29 mGy 降低到 13.84±2.94 mGy（p<0.001）。两种方案之间以及两位观察者之间的客观和主观图像质量均无显著差异。
新型三阶段 vHP3 方案可显著降低 TAVI/TAVR 术前 CT 的辐射剂量，而不影响图像质量。
·与联合 ECG 同步和非 ECG 同步螺旋 CT 方案相比，用于 TAVI/TAVR 术前 CT 的新型三阶段方案可降低 37%的辐射剂量。·客观图像质量不受影响，因为两种方案之间的图像噪声、SNR 和 CNR 无显著差异。主动脉根部和腹部主动脉的平均衰减均超过 450 HU。·两种方案的平均主观图像质量评分均为良好至极好，观察者间的一致性接近完美至显著。
