Lamb Christopher R, Dirrig Helen, Cortellini Stefano
Department of Clinical Sciences and Services, The Royal Veterinary College, University of London, London, UK.
J Feline Med Surg. 2018 Oct;20(10):948-954. doi: 10.1177/1098612X17736657. Epub 2017 Oct 11.
Objectives The objective of this study was to identify the renal ultrasonographic (US) findings most strongly associated with azotaemia in cats. Methods US findings in 238 cats with (serum creatinine >180 μmol/l) and 270 cats without azotaemia were compared in a retrospective case-control study. Cats with pre-renal azotaemia or urethral obstruction were excluded. Data extracted from the medical records included age, body weight and body condition score (BCS). Quantitative and subjective US findings were extracted from archived ultrasound images and contemporaneous reports. Results In non-azotaemic cats, mean ± SD renal length was 40.1 ± 5.5 mm. Male cats had larger kidneys than female cats (mean difference 5.2 mm; P = 0.001) and, on average, the right kidney was slightly larger than the left (mean difference 1.6 mm; P = 0.01). Azotaemic cats had significantly lower mean body weight and BCS, and greater mean age and renal pelvic diameter. Renal pelvic diameter was negatively correlated with urine specific gravity (ρ -0.44, P <0.001). Compared with non-azotaemic cats, there was no difference in mean renal length of azotaemic cats because the numbers with enlarged kidneys and small kidneys were similar. Radiologists' subjective assessments of renal size differed markedly between azotaemic and non-azotaemic cats, with azotaemic cats more likely to be recorded falsely as having abnormally small or enlarged kidneys. US findings significantly associated with azotaemia were perinephric fluid (odds ratio [OR] 26.4, 95% confidence interval [CI] 3.4-207.7), small kidneys (OR 8.4, 95% CI 4.0-17.4), hyperechoic renal cortex (OR 4.1, 95% CI 2.2-7.6), loss of corticomedullary differentiation (OR 4.1, 95% CI 1.8-9.6), renal calculi (OR 2.7, 95% CI 1.4-4.9), enlarged kidneys (OR 2.5, 95% CI 1.2-5.5) and dilated renal pelvis (OR 1.6, 95% CI 1.3-1.9). Conclusions and relevance Perinephric fluid was the US finding most strongly associated with azotaemia in this study and may merit more emphasis than it has received to date. Bias in radiologists' subjective assessments of renal size suggests that other subjective findings will also be biased.
目的 本研究的目的是确定猫氮质血症最密切相关的肾脏超声（US）表现。方法 在一项回顾性病例对照研究中，比较了238只患有氮质血症（血清肌酐>180μmol/l）的猫和270只无氮质血症的猫的超声检查结果。排除有肾前性氮质血症或尿道梗阻的猫。从病历中提取的数据包括年龄、体重和体况评分（BCS）。从存档的超声图像和同期报告中提取定量和主观的超声检查结果。结果 在无氮质血症的猫中，平均±标准差肾长为40.1±5.5mm。雄性猫的肾脏比雌性猫大（平均差异5.2mm；P=0.001），平均而言，右肾略大于左肾（平均差异1.6mm；P=0.01）。氮质血症猫的平均体重和BCS显著较低，平均年龄和肾盂直径较大。肾盂直径与尿比重呈负相关（ρ-0.44，P<0.001）。与无氮质血症的猫相比，氮质血症猫的平均肾长没有差异，因为肾脏增大和缩小的数量相似。放射科医生对肾脏大小的主观评估在氮质血症和无氮质血症的猫之间有明显差异。氮质血症猫更有可能被错误记录为肾脏异常小或增大。与氮质血症显著相关的超声表现为肾周积液（优势比[OR]26.4，95%置信区间[CI]3.4-207.7）、小肾脏（OR 8.4，95%CI 4.0-17.4）、高回声肾皮质（OR 4.1，95%CI 2.2-7.6）、皮质髓质分界消失（OR 4.1，95%CI 1.8-9.6）、肾结石（OR 2.7，95%CI 1.4-4.9）、肾脏增大（OR 2.5，95%CI 1.2-5.5）和肾盂扩张（OR 1.6，95%CI 1.3-1.9）。结论及相关性 在本研究中，肾周积液是与氮质血症最密切相关的超声表现，可能比目前受到的关注更值得重视。放射科医生对肾脏大小主观评估中的偏差表明其他主观表现也会存在偏差。
