Department of Orthopaedic Surgery, Duke University Medical Center, Durham, North Carolina.
Department of Radiology, Duke University Medical Center, Durham, North Carolina.
J Bone Joint Surg Am. 2022 Jun 1;104(11):1004-1014. doi: 10.2106/JBJS.20.01916. Epub 2022 Apr 14.
Shoulder computed tomography (CT) is commonly utilized in preoperative planning for total shoulder arthroplasty. Conventional-dose shoulder CT may expose patients to more ionizing radiation than is necessary to provide high-quality images for this procedure. The purpose of this study was to evaluate the utility of simulated low-dose CT images for preoperative planning using manual measurements and common preoperative planning software.
Eighteen shoulder CT scans obtained for preoperative arthroplasty planning were used to generate CT images as if they had been acquired at reduced radiation dose (RD) levels of 75%, 50%, and 25% using a simulation technique that mimics decreased x-ray tube current. This technique was validated by quantitative comparison of simulated low-dose scans of a cadaver with actual low-dose scans. Glenoid version, glenoid inclination, and humeral head subluxation were measured using 2 commercially available software platforms and were also measured manually by 3 physicians. These measurements were then analyzed for agreement across RD levels for each patient. Tolerances of 5° of glenoid version, 5° of glenoid inclination, and 10% humeral head subluxation were used as equivalent for preoperative planning purposes.
At all RD levels evaluated, the preoperative planning software successfully segmented the CT images. Semiautomated software measurement of 25% RD images was within tolerances in 99.1% of measurements; for 50% RD images, within tolerances in 96.3% of measurements; and for 75% RD images, within tolerances in 100% of measurements. Manual measurements of 25% RD images were within these tolerances in 95.1% of measurements; for 50% RD images, in 98.8% of measurements; and for 75% RD images, in 99.4% of measurements.
Simulated low-dose CT images were sufficient for reliable measurement of glenoid version, glenoid inclination, and humeral head subluxation by preoperative planning software as well as by physician-observers. These findings suggest the potential for substantial reduction in RD in preoperative shoulder CT scans without compromising surgical planning.
The adoption of low-dose techniques in preoperative shoulder CT may lower radiation exposure for patients undergoing shoulder arthroplasty, without compromising image quality.
肩部计算机断层扫描（CT）常用于全肩关节置换术的术前规划。常规剂量的肩部 CT 可能会使患者暴露在比提供该手术高质量图像所需的更多电离辐射下。本研究的目的是评估使用手动测量和常见术前规划软件对模拟低剂量 CT 图像进行术前规划的效用。
使用模拟技术生成 18 例用于术前关节置换规划的肩部 CT 扫描的 CT 图像，该模拟技术模拟降低 X 射线管电流，从而使图像的辐射剂量（RD）水平降低至 75%、50%和 25%。通过对一具尸体的模拟低剂量扫描与实际低剂量扫描的定量比较验证了该技术的有效性。使用 2 种商业上可用的软件平台和 3 名医生进行测量，以测量关节盂倾斜度、关节盂倾斜度和肱骨头半脱位。然后，分析每个患者的 RD 水平的测量值的一致性。为了满足术前规划的目的，将关节盂倾斜度 5°、关节盂倾斜度 5°和肱骨头半脱位 10%的容差用于此。
在所评估的所有 RD 水平下，术前规划软件均成功分割了 CT 图像。在 99.1%的测量中，25%RD 图像的半自动软件测量值在容差范围内；在 96.3%的测量中，50%RD 图像的测量值在容差范围内；在 100%的测量中，75%RD 图像的测量值在容差范围内。在 95.1%的测量中，25%RD 图像的手动测量值在容差范围内；在 98.8%的测量中，50%RD 图像的测量值在容差范围内；在 99.4%的测量中，75%RD 图像的测量值在容差范围内。
模拟低剂量 CT 图像足以通过术前规划软件以及医师观察者进行可靠的关节盂倾斜度、关节盂倾斜度和肱骨头半脱位的测量。这些发现表明，在不影响手术计划的情况下，术前肩部 CT 扫描中采用低剂量技术有可能大幅降低 RD。
术前肩部 CT 采用低剂量技术可能会降低接受肩部关节置换术的患者的辐射暴露量，同时不影响图像质量。
