Departamento de Urologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, SP, Brasil.
Departamento de Radiologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, SP, Brasil.
Int Braz J Urol. 2019 Sep-Oct;45(5):948-955. doi: 10.1590/S1677-5538.IBJU.2018.0819.
Measurements of stone features may vary according to the non-contrast computed tomography (NCCT) technique. Using magnified bone window is the most accurate method to measure urinary stones. Possible differences between stone measurements in different NCCT windows have not been evaluated in stones located in the kidney. The aim of this study is to compare measurements of kidney stone features between NCCT bone and soft tissue windows in patients submitted to retrograde intrarenal surgery (RIRS).
Preoperative and 90th postoperative day NCCT were performed in 92 consecutive symptomatic adult patients (115 renal units) with kidney stones between 5 mm to 20 mm (< 15 mm in the lower calyx) treated by RIRS. NCCT were evaluated in the magnified bone window and soft tissue window in three axes in a different time by a single radiologist blinded for the measurements of the NCCT other method.
Stone largest size (7.92±3.81 vs. 9.13±4.08; mm), volume (435.5±472.7 vs. 683.1±665.0; mm3) and density (989.4±330.2 vs. 893.0±324.6; HU) differed between bone and soft-tissue windows, respectively (p<0.0001) 5.2% of the renal units (6/115) were reclassified from residual fragments > 2 mm on soft tissue window to 0-2 mm on bone window.
Kidney stone measurements vary according to NCCT window. Measurements in soft tissue window NCCT of stone diameter and volume are larger and stone density is lesser than in bone window. These differences may have impact on clinical decisions.
结石特征的测量值可能因非增强计算机断层扫描（NCCT）技术而异。使用放大的骨窗是测量尿路结石最准确的方法。尚未评估不同 NCCT 窗口中结石测量值之间的差异在肾脏结石中。本研究旨在比较经逆行肾内手术（RIRS）治疗的患者的 NCCT 骨窗和软组织窗中肾结石特征的测量值。
对 92 例连续症状性成年患者（115 个肾脏单位）的术前和术后第 90 天的 NCCT 进行了检查，这些患者的肾结石大小为 5 毫米至 20 毫米（下盏结石<15 毫米），采用 RIRS 治疗。由一位对 NCCT 其他方法的测量结果不知情的放射科医生在不同时间对放大的骨窗和软组织窗的三个轴位进行了评估。
结石最大尺寸（7.92±3.81 与 9.13±4.08；mm）、体积（435.5±472.7 与 683.1±665.0；mm3）和密度（989.4±330.2 与 893.0±324.6；HU）在骨窗和软组织窗之间存在差异（p<0.0001）。5.2%的肾脏单位（6/115）从软组织窗上>2mm 的残留碎片重新分类为骨窗上的 0-2mm。
肾结石的测量值因 NCCT 窗口而异。软组织窗 NCCT 测量的结石直径和体积较大，而结石密度较小。这些差异可能对临床决策产生影响。
