非增强 CT 上的绝对亨氏单位测量不能准确预测鸟粪石结石成分。

Absolute Hounsfield unit measurement on noncontrast computed tomography cannot accurately predict struvite stone composition.

机构信息

Glickman Urological and Kidney Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.

出版信息

J Endourol. 2013 Feb;27(2):162-7. doi: 10.1089/end.2012.0470. Epub 2012 Dec 7.

DOI:10.1089/end.2012.0470

PMID:22974047

Abstract

BACKGROUND

The purpose of our study was to determine, in vivo, whether single-energy noncontrast computed tomography (NCCT) can accurately predict the presence/percentage of struvite stone composition.

METHODS

We retrospectively searched for all patients with struvite components on stone composition analysis between January 2008 and March 2012. Inclusion criteria were NCCT prior to stone analysis and stone size ≥4 mm. A single urologist, blinded to stone composition, reviewed all NCCT to acquire stone location, dimensions, and Hounsfield unit (HU). HU density (HUD) was calculated by dividing mean HU by the stone's largest transverse diameter. Stone analysis was performed via Fourier transform infrared spectrometry. Independent sample Student's t-test and analysis of variance (ANOVA) were used to compare HU/HUD among groups. Spearman's correlation test was used to determine the correlation between HU and stone size and also HU/HUD to % of each component within the stone. Significance was considered if p<0.05.

RESULTS

Fourty-four patients met the inclusion criteria. Struvite was the most prevalent component with mean percentage of 50.1%±17.7%. Mean HU and HUD were 820.2±357.9 and 67.5±54.9, respectively. Struvite component analysis revealed a nonsignificant positive correlation with HU (R=0.017; p=0.912) and negative with HUD (R=-0.20; p=0.898). Overall, 3 (6.8%) had <20% of struvite component; 11 (25%), 25 (56.8%), and 5 (11.4%) had 21% to 40%, 41% to 60%, and 61% to 80% of struvite, respectively. ANOVA revealed no difference among groups regarding HU (p=0.68) and HUD (p=0.37), with important overlaps. When comparing pure struvite stones (n=5) with other miscellaneous stones (n=39), no difference was found for HU (p=0.09) but HUD was significantly lower for pure stones (27.9±23.6 v 72.5±55.9, respectively; p=0.006). Again, significant overlaps were seen.

CONCLUSIONS

Pure struvite stones have significantly lower HUD than mixed struvite stones, but overlap exists. A low HUD may increase the suspicion for a pure struvite calculus.

摘要

背景

本研究旨在体内确定单能非对比 CT（NCCT）能否准确预测鸟粪石结石成分的存在/百分比。

方法

我们回顾性搜索了 2008 年 1 月至 2012 年 3 月之间结石成分分析中存在鸟粪石成分的所有患者。纳入标准为结石分析前有 NCCT 检查，且结石大小≥4mm。一位对结石成分不知情的泌尿科医生对所有 NCCT 进行了回顾，以获取结石的位置、尺寸和亨氏单位（HU）。HU 密度（HUD）通过将平均 HU 除以结石的最大横径来计算。结石分析通过傅里叶变换红外光谱法进行。使用独立样本 t 检验和方差分析（ANOVA）比较各组之间的 HU/HUD。使用斯皮尔曼相关检验确定 HU 与结石大小之间的相关性，以及 HU/HUD 与结石内各成分的百分比之间的相关性。如果 p<0.05，则认为有统计学意义。

结果

44 名患者符合纳入标准。鸟粪石是最常见的成分，平均百分比为 50.1%±17.7%。平均 HU 和 HUD 分别为 820.2±357.9 和 67.5±54.9。鸟粪石成分分析显示，HU 呈正相关（R=0.017；p=0.912），与 HUD 呈负相关（R=-0.20；p=0.898）。总体而言，有 3 名患者（6.8%）鸟粪石成分<20%；11 名患者（25%）、25 名患者（56.8%）和 5 名患者（11.4%）鸟粪石成分分别为 21%至 40%、41%至 60%和 61%至 80%。ANOVA 显示各组之间在 HU（p=0.68）和 HUD（p=0.37）方面无差异，且存在重要重叠。当比较纯鸟粪石结石（n=5）与其他混合结石（n=39）时，HU 无差异（p=0.09），但纯鸟粪石结石的 HUD 明显较低（分别为 27.9±23.6 和 72.5±55.9；p=0.006）。同样，存在显著重叠。