Low Russell N, Sebrechts Christopher P, Barone Robert M, Muller Wayne
Sharp and Children's MRI Center, 7901 Frost St., San Diego, CA 92123, USA.
AJR Am J Roentgenol. 2009 Aug;193(2):461-70. doi: 10.2214/AJR.08.1753.
The purpose of our study was to evaluate the utility of single-shot spin-echo echo-planar diffusion-weighted imaging (DWI) using a b value of 400-500 s/mm(2) for depicting peritoneal tumors.
Thirty-four consecutive oncology patients underwent preoperative abdominal and pelvic MRI for tumor staging. MRI included breath-hold DWI with a b value of 400-500 s/mm(2), T1-weighted spoiled gradient-echo, T2-weighted fast spin-echo, and 0- and 5-minute delayed gadolinium-enhanced imaging. At three separate sessions, two observers independently reviewed images for peritoneal tumors at 16 anatomic sites. First DWI alone was reviewed, followed by conventional MRI alone, and then conventional MRI, including DWI, was reviewed. Results of laparotomy and histopathologic evaluation were compared with MRI results. Sensitivity, specificity, and accuracy were calculated for DWI, conventional MRI, and combined DWI and conventional MRI for peritoneal tumor depiction.
Two-hundred fifty-five sites of peritoneal tumor were proven by surgical and histopathologic findings. The combination of DWI and conventional MRI was most sensitive and accurate for peritoneal tumors, depicting 230 and 214 tumor sites for the two observers (sensitivity, 0.90, 0.84; and accuracy, 0.91, 0.88) compared with DWI alone, which depicted 182 and 182 tumor sites with sensitivity (0.71, 0.71; and accuracy, 0.81, 0.81), and conventional MRI alone, which depicted 185 and 132 tumor sites (sensitivity, 0.73, 0.52; and accuracy, 0.81, 0.72). Peritoneal tumor showed restricted diffusion on DWI and ascites was of low signal intensity, increasing tumor conspicuity.
Adding DWI to routine MRI improves the sensitivity and specificity for depicting peritoneal metastases. Breath-hold DWI is now routinely used in all oncology patients referred for abdominal MRI at our institution.
本研究旨在评估使用b值为400 - 500 s/mm²的单次激发自旋回波平面扩散加权成像（DWI）对腹膜肿瘤的诊断价值。
34例连续的肿瘤患者术前行腹部和盆腔MRI检查以进行肿瘤分期。MRI检查包括屏气DWI（b值为400 - 500 s/mm²）、T1加权扰相梯度回波序列、T2加权快速自旋回波序列以及0分钟和5分钟延迟钆增强成像。在三个不同阶段，两名观察者分别独立对16个解剖部位的腹膜肿瘤图像进行评估。首先单独评估DWI图像，接着单独评估传统MRI图像，然后评估包括DWI的传统MRI图像。将剖腹手术及组织病理学评估结果与MRI结果进行比较。计算DWI、传统MRI以及DWI与传统MRI联合用于腹膜肿瘤诊断的敏感性、特异性和准确性。
手术及组织病理学检查证实255个腹膜肿瘤部位。DWI与传统MRI联合对腹膜肿瘤的诊断最为敏感和准确，两名观察者分别发现230个和214个肿瘤部位（敏感性分别为0.90、0.84；准确性分别为0.91、0.88）；单独DWI发现182个和182个肿瘤部位（敏感性分别为0.71、0.71；准确性分别为0.81、0.81）；单独传统MRI发现185个和132个肿瘤部位（敏感性分别为0.73、0.52；准确性分别为0.81、0.72）。腹膜肿瘤在DWI上表现为扩散受限，腹水呈低信号强度，提高了肿瘤的显影效果。
在常规MRI检查中加入DWI可提高腹膜转移瘤诊断的敏感性和特异性。目前在我院，所有因腹部MRI检查而转诊的肿瘤患者均常规进行屏气DWI检查。
