A comparative study of ultrasound and cross-sectional imaging for detection of small renal masses: anatomic factors and radiologist's experience

ABSTRACT Objective: To evaluate anatomic factors and radiologist's experience in the detection of solid renal masses on ultrasonography. Methods: We searched for solid renal masses diagnosed on cross-sectional imaging from 2007 to 2017 that also had previous ultrasonography from the past 6 months. The following features were evaluated: nodule size, laterality, location and growth pattern, patient body mass index and radiologist's experience in ultrasound. In surgically resected cases, pathologic reports were evaluated. Unpaired t test and χ2 test were used to evaluate differences among subgroups, using R-statistics. Statistical significance was set at p<0.05. Results: The initial search of renal nodules on cross-sectional imaging resulted in 428 lesions and 266 lesions were excluded. Final cohort included 162 lesions and, of those, 108 (67%) were correctly detected on ultrasonography (Group 1) and 54 (33%) were missed (Group 2). Comparison of Groups 1 and 2 were as follows, respectively: body mass index (27.7 versus 27.1; p=0.496), size (2.58cm versus 1.74cm; p=0.003), laterality (54% versus 59% right sided; p=0.832), location (27% versus 22% upper pole; p=0.869), growth pattern (25% versus 28% endophytic; p=0.131) and radiologist's experience (p=0.300). From surgically resected cases, histology available for Group 1 was clear cell (n=11), papillary (n=15), chromophobe (n=2) renal cell carcinoma, oncocytoma (n=1), and, for Group 2, clear cell (n=7), papillary (n=5) renal cell carcinoma, oncocytoma (n=2), angiomyolipoma, chromophobe renal cell carcinoma, and interstitial pyelonephritis (n=1, each). Conclusion: Size was the only significant parameter related to renal nodule detection on ultrasound.

摘要 研究目的：评估解剖学因素及放射科医师的阅片经验对超声检查（ultrasonography）检出肾脏实性占位的影响。研究方法：检索2007年至2017年间经横断面成像（cross-sectional imaging）确诊的肾脏实性占位病例，且所有病例均在近6个月内接受过超声检查。本研究评估的指标包括：结节大小、侧别、位置、生长方式、患者体质量指数（body mass index）以及放射科医师的超声阅片经验。对于手术切除的病例，进一步评估其病理报告结果。采用R统计软件（R-statistics）进行分析，使用成组t检验（unpaired t test）和卡方（χ²）检验比较各亚组间的差异，设定检验水准p<0.05为具有统计学意义。研究结果：初始横断面成像检索共检出428个肾脏结节，最终排除266个病灶。最终纳入分析的队列共162个病灶，其中108个（67%）经超声正确检出（第1组），54个（33%）被漏诊（第2组）。两组的比较结果如下：体质量指数分别为27.7与27.1（p=0.496），结节大小分别为2.58cm与1.74cm（p=0.003），右侧病灶占比分别为54%与59%（p=0.832），肾上极病灶占比分别为27%与22%（p=0.869），内生型生长占比分别为25%与28%（p=0.131），放射科医师阅片经验的差异无统计学意义（p=0.300）。手术切除病例的组织病理学结果：第1组包括肾透明细胞癌（clear cell renal cell carcinoma）11例、乳头状肾细胞癌（papillary renal cell carcinoma）15例、嫌色细胞肾细胞癌（chromophobe renal cell carcinoma）2例、嗜酸细胞瘤（oncocytoma）1例；第2组包括肾透明细胞癌7例、乳头状肾细胞癌5例、嗜酸细胞瘤2例、血管平滑肌脂肪瘤（angiomyolipoma）1例、嫌色细胞肾细胞癌1例以及间质性肾盂肾炎（interstitial pyelonephritis）1例。结论：结节大小是唯一与超声检出肾脏结节相关的具有统计学意义的参数。