Department of Urology, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.
Department of Pediatrics, Marienhaus Hospital St. Elisabeth Neuwied, Neuwied, Germany.
Urol Int. 2021;105(7-8):600-604. doi: 10.1159/000515646. Epub 2021 Apr 29.
Low-dose computer tomography (NCCT) is the standard imaging modality for patients with acute flank pain with a suspicion of urolithiasis. The stone size is usually measured 2D by a radiologist. We compared 3D stone measurement using different windows to the 2D measurement and evaluated the clinical impact on ureterorenoscopic stone removal (URS).
One hundred sixty-four patients (201 stones) with a preoperative NCCT, following a URS within 4 weeks, were included in this study. Stone location, number and size of stones, operating time, and laser lithotripsy were documented. Stones were measured in 3D using bone and soft tissue window. The maximum diameter was compared to the radiological report. The U test, Kruskal-Wallis, and regression were used for statistical analyses.
Almost two-thirds (64.68%; 130 stones) of stone measurements in 3D with the bone window were lower than the radiologist reports in 2D. One-third (34.83%; 70 stones) of stone measurements were higher and 0.5% (1 stone) reported the same size. Using the 3D soft tissue window, 81.09% (163 stones), 17.91% (37 stones), and 1% (2 stones) of stones were measured bigger, smaller, or had the same measurement results, respectively. In the clinical setting, we could calculate a cutoff for laser lithotripsy at a maximum stone diameter of 5.70 mm (p < 0.01) with the 3D and 6.01 mm with the 2D measurements, respectively, and found a significant correlation between maximum stone diameter and operating time (p < 0.01) and number of stones and operating time (p < 0.01 with and p = 0.02 without laser).
3D stone measurement with bone window seems to be more accurate than 2D measurement, but 2D is sufficient for planning stone treatment.
低剂量计算机断层扫描（NCCT）是怀疑患有尿路结石的急性腰痛患者的标准影像学检查方法。放射科医生通常通过 2D 来测量结石的大小。我们比较了不同窗口下的 3D 结石测量与 2D 测量，并评估了其对输尿管镜碎石术（URS）的临床影响。
本研究纳入了 164 例（201 个结石）术前接受 NCCT 检查并在 4 周内接受 URS 的患者。记录结石位置、结石数量和大小、手术时间和激光碎石情况。使用骨窗和软组织窗在 3D 下测量结石，将最大直径与放射科报告进行比较。采用 U 检验、Kruskal-Wallis 检验和回归分析进行统计学分析。
在 3D 下使用骨窗测量的结石中，有近三分之二（64.68%；130 个结石）的测量值低于放射科医生在 2D 下的报告值。三分之一（34.83%；70 个结石）的测量值更高，而 0.5%（1 个结石）的报告值相同。在临床应用中，我们可以使用 3D 软组织窗分别计算出激光碎石的截止值为最大结石直径 5.70mm（p<0.01）和 6.01mm（p<0.01），且发现最大结石直径与手术时间之间存在显著相关性（p<0.01），以及结石数量与手术时间之间存在显著相关性（p<0.01 时未行激光碎石，p=0.02 时行激光碎石）。
与 2D 测量相比，3D 骨窗结石测量似乎更准确，但 2D 足以用于计划结石治疗。
