Institute of Neuroradiology, University Hospital, LMU Munich, Marchioninistrasse 15, 81377, Munich, Germany.
Center of Radiology and Neuroradiology, Klinikum Ingolstadt, Ingolstadt, Germany.
Eur Radiol. 2019 Jun;29(6):2859-2867. doi: 10.1007/s00330-018-5930-0. Epub 2019 Jan 11.
Intraoperative CT (iCT) angiography of the brain with stereotactic frames is an integral part of navigated neurosurgery. Validated data regarding radiation dose and image quality in these special examinations are not available. We therefore investigated two iCT protocols in this IRB-approved study.
Retrospective analysis of patients, who received a cerebral stereotactic iCT angiography on a 128 slice CT scanner between February 2016 and December 2017. In group A, automated tube current modulation (ATCM; reference value 410 mAs) and automated tube voltage selection (reference value 120 kV) were enabled, and only examinations with a selected voltage of 120 kV were included. In group B, fixed parameters were applied (300 mAs, 120 kV). Radiation dose was measured by assessing the volumetric CT dose index (CTDI), dose length product (DLP) and effective dose (ED). Signal-to-noise ratio (SNR) and image noise were assessed for objective image quality, visibility of arteries and grey-white differentiation for subjective image quality.
Two hundred patients (n = 100 in each group) were included. In group A, median selected tube current was 643 mAs (group B, 300 mAs; p < 0.001). Median values of CTDI, DLP and ED were 91.54 mGy, 1561 mGy cm and 2.97 mSv in group A, and 43.15 mGy, 769 mGy cm and 1.46 mSv in group B (p < 0.001). Image quality did not significantly differ between groups (p > 0.05).
ATCM yielded disproportionally high radiation dose due to substantial tube current increase at the frame level, while image quality did not improve. Thus, ATCM should preferentially be disabled.
• Automated tube current modulation (ATCM) yields disproportionally high radiation dose in intraoperative CT angiography of the brain with stereotactic head frames. • ATCM does not improve overall image quality in these special examinations. • ATCM is not yet optimised for CT angiography of the brain with major extracorporeal foreign materials within the scan range.
脑立体定向框架术中 CT（iCT）血管造影是神经导航手术的重要组成部分。目前尚无关于这些特殊检查的辐射剂量和图像质量的验证数据。因此，我们在这项经过机构审查委员会批准的研究中调查了两种 iCT 方案。
回顾性分析 2016 年 2 月至 2017 年 12 月期间在 128 层 CT 扫描仪上接受脑立体定向 iCT 血管造影的患者。在组 A 中，启用了自动管电流调制（ATCM；参考值 410 mAs）和自动管电压选择（参考值 120 kV），并且仅纳入选择电压为 120 kV 的检查。在组 B 中，应用了固定参数（300 mAs，120 kV）。通过评估容积 CT 剂量指数（CTDI）、剂量长度乘积（DLP）和有效剂量（ED）来测量辐射剂量。为了评估客观图像质量，评估了信噪比（SNR）和图像噪声，为了评估主观图像质量，评估了动脉的可见度和灰白质分化。
共纳入 200 例患者（每组 100 例）。在组 A 中，中位数选择的管电流为 643 mAs（组 B 为 300 mAs；p < 0.001）。组 A 的 CTDI、DLP 和 ED 的中位数值分别为 91.54 mGy、1561 mGy·cm 和 2.97 mSv，组 B 分别为 43.15 mGy、769 mGy·cm 和 1.46 mSv（p < 0.001）。组间图像质量无显著差异（p > 0.05）。
由于框架层面的管电流显著增加，ATCM 导致不成比例的高辐射剂量，而图像质量并未改善。因此，应优先禁用 ATCM。
脑立体定向框架术中 CT 血管造影的自动管电流调制（ATCM）会产生不成比例的高辐射剂量。
ATCM 并不能改善这些特殊检查的整体图像质量。
ATCM 尚未针对扫描范围内有大量体外异物的脑部 CT 血管造影进行优化。
