Department of Radiology, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, IA, 52242, USA.
Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA, USA.
Neuroradiology. 2020 Aug;62(8):965-970. doi: 10.1007/s00234-020-02406-y. Epub 2020 Apr 10.
We hypothesized that cerebral CT angiogram performed using third-generation reconstruction algorithm and lower contrast dose-low-kVp technique (LD-CTA) will provide better image quality when compared with regular contrast dose CTA at 120 kVp using a sinogram-affirmed iterative reconstruction algorithm (ND-CTA).
Retrospective imaging review of 100 consecutive patients (50 each in LD- and ND-CTA groups). Two readers independently assessed the subjective image quality across multiple vascular segments on a Likert-like scale. Differences in contrast dose, CT dose index (CTDI), and dose length product (DLP) were compared using Mann-Whitney U test. Fisher's exact test was used to compare subjective image quality. Similarly, contrast- and signal-to-noise ratios (CNR and SNR) were compared in the mid-M1 MCA vessels bilaterally and the mid-basilar artery using Mann-Whitney U test. Interclass correlation coefficient (ICC) was calculated for the SNR/CNR values.
Both observers showed excellent correlation in subjective image quality (mean percentage agreement of 95.2% for group 1 versus 89.2% for group 2). LD-CTA group showed better SNR and CNR (p < 0.0001) for both MCA vessels and the mid-basilar artery. Interclass correlation coefficient showed moderate correlation (0.51-0.63) between readers. LD-CTA group also used lower contrast (49 cc versus 97 cc in ND-CTA) and had lower radiation exposure (DLP/CTDI for both groups 268.3/80.7 vs 519.5/36.08, both < 0.0001).
Next-generation reconstruction algorithm and low-kV scanning significantly improved image quality on cerebral CTA images despite lower contrast dose and, in addition, have lower radiation exposure.
我们假设与使用常规造影剂剂量 120kVp 下的正弦图确认迭代重建算法（ND-CTA）相比，使用第三代重建算法和低对比剂剂量-低千伏技术（LD-CTA）进行的脑 CT 血管造影术将提供更好的图像质量。
回顾性分析了 100 例连续患者（每组 50 例，分别在 LD-和 ND-CTA 组）的影像学检查结果。两名读者独立使用类似于李克特量表的评分标准评估多个血管段的主观图像质量。使用 Mann-Whitney U 检验比较造影剂剂量、CT 剂量指数（CTDI）和剂量长度乘积（DLP）的差异。使用 Fisher 确切检验比较主观图像质量。同样，使用 Mann-Whitney U 检验比较双侧大脑中动脉（MCA）中部和基底动脉中部的对比噪声比（CNR）和信噪比（SNR）。计算 SNR/CNR 值的组内相关系数（ICC）。
两名观察者在主观图像质量方面均显示出极好的相关性（组 1 的平均百分比一致性为 95.2%，组 2 为 89.2%）。LD-CTA 组在双侧 MCA 血管和基底动脉中部均显示出更好的 SNR 和 CNR（p < 0.0001）。组内相关系数显示出观察者之间中等程度的相关性（0.51-0.63）。LD-CTA 组还使用了较低的造影剂剂量（ND-CTA 组为 49cc，LD-CTA 组为 97cc），且辐射暴露更低（两组的 DLP/CTDI 分别为 268.3/80.7 与 519.5/36.08，均 < 0.0001）。
尽管造影剂剂量较低，但下一代重建算法和低千伏扫描显著提高了脑 CT 血管造影图像的质量，并且还降低了辐射暴露。
