Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Strasse 22, 81675 Munich, Germany.
TUM-Neuroimaging Center, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.
AJR Am J Roentgenol. 2021 May;216(5):1308-1317. doi: 10.2214/AJR.20.23083. Epub 2021 Mar 11.
The purpose of our study was to evaluate simulated sparse-sampled MDCT combined with statistical iterative reconstruction (SIR) for low-dose imaging of patients with spinal instrumentation. Thirty-eight patients with implanted hardware after spinal instrumentation (24 patients with short- or long-term instrumentation-related complications [i.e., adjacent segment disease, screw loosening or implant failure, or postoperative hematoma or seroma] and 14 control subjects with no complications) underwent MDCT. Scans were simulated as if they were performed with 50% (P50), 25% (P25), 10% (P10), and 5% (P5) of the projections of the original acquisition using an in-house-developed SIR algorithm for advanced image reconstructions. Two readers performed qualitative image evaluations of overall image quality and artifacts, image contrast, inspection of the spinal canal, and diagnostic confidence (1 = high, 2 = medium, and 3 = low confidence). Although overall image quality decreased and artifacts increased with reductions in the number of projections, all complications were detected by both readers when 100% of the projections of the original acquisition (P100), P50, and P25 imaging data were used. For P25 data, diagnostic confidence was still high (mean score ± SD: reader 1, 1.2 ± 0.4; reader 2, 1.3 ± 0.5), and interreader agreement was substantial to almost perfect (weighted Cohen κ = 0.787-0.855). The mean volumetric CT dose index was 3.2 mGy for P25 data in comparison with 12.6 mGy for the original acquisition (P100 data). The use of sparse sampling and SIR for low-dose MDCT in patients with spinal instrumentation facilitated considerable reductions in radiation exposure. The use of P25 data with SIR resulted in no missed complications related to spinal instrumentation and allowed high diagnostic confidence, so using only 25% of the projections is probably enough for accurate and confident diagnostic detection of major instrumentation-related complications.
我们的研究目的是评估模拟稀疏采样 MDCT 结合统计迭代重建（SIR）在脊柱内固定术后患者低剂量成像中的应用。38 例脊柱内固定术后植入内固定物的患者（24 例有短期或长期与内固定物相关的并发症[即相邻节段疾病、螺钉松动或植入物失败、术后血肿或血清肿]，14 例无并发症的对照组）接受 MDCT 检查。使用我们自主开发的 SIR 算法对原始采集的投影进行模拟，模拟采集以 50%（P50）、25%（P25）、10%（P10）和 5%（P5）的投影进行。两位读者对整体图像质量和伪影、图像对比度、椎管检查和诊断信心（1=高，2=中，3=低）进行定性图像评估。尽管随着投影数量的减少，整体图像质量下降，伪影增加，但当使用原始采集的 100%（P100）、P50 和 P25 成像数据时，两位读者均能检测到所有并发症。对于 P25 数据，诊断信心仍然很高（平均评分±SD：读者 1，1.2±0.4；读者 2，1.3±0.5），并且两位读者之间的一致性为中等至高（加权 Cohen κ=0.787-0.855）。与原始采集（P100 数据）的 12.6 mGy 相比，P25 数据的容积 CT 剂量指数平均为 3.2 mGy。在脊柱内固定患者中，稀疏采样和 SIR 用于低剂量 MDCT 可显著降低辐射暴露。使用 SIR 的 P25 数据不会遗漏与脊柱内固定物相关的并发症，并允许高诊断信心，因此仅使用 25%的投影可能足以准确和有信心地诊断主要与内固定物相关的并发症。
