Esser Michael, Tsiflikas Ilias, Jago James R, Rouet Laurence, Stebner Alexander, Schäfer Jürgen F
Department of Diagnostic and Interventional Radiology, Universitätsklinikum Tübingen, Hoppe-Seyler-Str.3, 72076, Tübingen, Germany.
Philips Healthcare, Ultrasound General Imaging, Bothell, WA, United States.
Pediatr Radiol. 2025 May;55(6):1298-1307. doi: 10.1007/s00247-025-06249-8. Epub 2025 May 6.
Two-dimensional (D) assessment of renal volume underestimates the actual value and shows high interobserver variability. Limited data exist on innovative 3-D ultrasound (US) technique for the evaluation of pediatric hydronephrosis.
To assess the interrater agreement of kidney volume segmentation by 3-D US with a matrix array transducer in children with hydronephrosis and to compare the 3-D metrics to conventional hydronephrosis grading.
We prospectively acquired 48 renal volumes in 45 patients with hydronephrosis by freehand 3-D US (6-1 MHz volumetric sector array, electronic rotation; median age, 4 years; 1 month to 16 years). Semi-automated kidney segmentation was performed by two independent readers providing volumes for total kidney (renal capsule), dilated collective system, renal parenchyma (renal capsule-collective system) and hydronephrosis index (renal parenchyma/capsule). Interrater agreement was evaluated with Bland-Altman plots, intraclass correlation coefficient (ICC) and Dice similarity coefficients. The maximum calibre of renal pelvis was measured and hydronephroses were morphologically classified grade 1-4.
Interrater agreement for renal capsule, collective system, hydronephrosis index, and renal parenchyma was good to excellent with ICC of 0.94, 0.87, 0.83 and 0.92 respectively (P < 0.001 each). Median Dice was 0.90 (capsule), 0.77 (collective system) and 0.88 (parenchyma). There was a positive correlation between conventional hydronephrosis grading and ultrasonic hydronephrosis index and between renal pelvis diameter and collective system volume (P < 0.001 both).
Semiautomatic 3-D US volumetric analysis has a high degree of interrater agreement and enables reliable assessment of renal parenchymal volume in hydronephrosis. Volumes of the collective system and hydronephrosis index correlate with the extent of hydronephrosis.
Trial registration number, DRKS00022772; date of registration, 07/31/2020.
二维（2D）评估肾体积会低估实际值，且观察者间差异较大。关于用于评估小儿肾积水的创新三维（3D）超声（US）技术的数据有限。
评估使用矩阵阵列换能器的三维超声对肾积水患儿肾体积分割的观察者间一致性，并将三维测量指标与传统肾积水分级进行比较。
我们前瞻性地通过徒手三维超声（6 - 1MHz容积扇形阵列，电子旋转；中位年龄4岁；1个月至16岁）获取了45例肾积水患者的48个肾体积。由两名独立的阅片者进行半自动肾脏分割，提供全肾（肾包膜）、扩张的集合系统、肾实质（肾包膜 - 集合系统）和肾积水指数（肾实质/包膜）的体积。通过Bland - Altman图、组内相关系数（ICC）和Dice相似系数评估观察者间一致性。测量肾盂最大内径，并对肾积水进行形态学1 - 4级分类。
肾包膜、集合系统、肾积水指数和肾实质的观察者间一致性良好至优秀，ICC分别为0.94、0.87、0.83和0.92（均P < 0.001）。Dice中位数分别为0.90（包膜）、0.77（集合系统）和0.88（实质）。传统肾积水分级与超声肾积水指数之间以及肾盂直径与集合系统体积之间存在正相关（均P < 0.001）。
半自动三维超声容积分析具有高度的观察者间一致性，能够可靠地评估肾积水时的肾实质体积。集合系统体积和肾积水指数与肾积水程度相关。
试验注册号，DRKS00022772；注册日期，2020年7月31日。
