Oto Aytekin, Schmid-Tannwald Christine, Agrawal Garima, Kayhan Arda, Lakadamyali Hatice, Orrin Sarah, Sethi Ila, Sammet Steffen, Fan Xiaobing
Department of Radiology, University of Chicago, 5841 S. Maryland Avenue, MC 2026, Chicago, IL 60637, USA.
Emerg Radiol. 2011 Dec;18(6):515-24. doi: 10.1007/s10140-011-0976-1. Epub 2011 Aug 9.
This study was conducted to determine the incremental value of diffusion-weighted MR imaging (DW-MRI) over T2-weighted imaging diagnosing abdominopelvic abscesses and compare apparent diffusion coefficient (ADC) values of abscesses and non-infected ascites. In this IRB-approved, HIPAA-compliant study, two radiologists retrospectively compared T2-weighted, T2-weighted + DW-MRI and T2-weighted + contrast enhanced MR images of 58 patients (29 with abscess, 29 with ascites) who underwent abdominal MRI for abscess detection. Confidence and sensitivity was compared using McNemar's test. ADC of abscesses and ascites was compared by t test, and a receiver operating characteristic (ROC) curve was constructed. Detection of abscesses and confidence improved significantly when T2-weighted images were combined with DW-MRI (sensitivity: observer 1-100%, observer 2-96.6%) or contrast enhanced images (sensitivity: both observers-100%) compared to T2-weighted images alone (sensitivity: observer 1-65.5%, observer 2-72.4%). All abscesses showed restricted diffusion. Mean ADC of abscesses (observer 1-1.17 ± 0.42 × 10(-)³ mm²/s, observer 2-1.43 ± 0.48 × 10(-3) mm²/s) was lower than ascites (observer 1-3.57 ± 0.68 × 10(-3) mm²/s, observer 2-3.42 ± 0.67 × 10(-3) mm²/s) (p < 0.01). ROC analysis showed perfect discrimination of abscess from ascites with threshold ADC of 2.0 × 10(-3) mm²/s (Az value 1.0). DW-MRI is a valuable adjunct to T2-weighted images diagnosing abdominopelvic abscesses. ADC measurements may have the potential to differentiate abdominal abscesses from ascites.
本研究旨在确定扩散加权磁共振成像（DW-MRI）相对于T2加权成像在诊断腹盆腔脓肿方面的增量价值，并比较脓肿与非感染性腹水的表观扩散系数（ADC）值。在这项经机构审查委员会（IRB）批准且符合健康保险流通与责任法案（HIPAA）的研究中，两位放射科医生回顾性比较了58例接受腹部MRI以检测脓肿患者（29例有脓肿，29例有腹水）的T2加权、T2加权+DW-MRI以及T2加权+对比增强MR图像。使用McNemar检验比较信心度和敏感度。通过t检验比较脓肿与腹水的ADC，并构建受试者操作特征（ROC）曲线。与单独的T2加权图像（敏感度：观察者1为65.5%，观察者2为72.4%）相比，当T2加权图像与DW-MRI（敏感度：观察者1为100%，观察者2为96.6%）或对比增强图像（敏感度：两位观察者均为100%）相结合时，脓肿的检测及信心度显著提高。所有脓肿均表现为扩散受限。脓肿的平均ADC（观察者1为1.17±0.42×10⁻³mm²/s，观察者2为1.43±0.48×10⁻³mm²/s）低于腹水（观察者1为3.57±0.68×10⁻³mm²/s，观察者2为3.42±0.67×10⁻³mm²/s）（p<0.01）。ROC分析显示，以2.0×10⁻³mm²/s的ADC阈值可完美区分脓肿与腹水（Az值为1.0）。DW-MRI是T2加权图像诊断腹盆腔脓肿的有价值辅助手段。ADC测量可能具有区分腹部脓肿与腹水 的潜力。
