Department of Radiology, Atatürk University, School of Medicine, Dadaskent, Erzurum 25090, Turkey.
AJR Am J Roentgenol. 2010 Oct;195(4):W268-73. doi: 10.2214/AJR.10.4221.
The aim of this feasibility study was to evaluate the role of diffusion-weighted MRI in the evaluation of nonpalpable undescended testes.
Thirty-six boys with undescended testes underwent preoperative abdominal and pelvic MRI to identify the location of the testes. MRI included free-breathing diffusion-weighted imaging (DWI) with b values of 50, 400, and 800 s/mm(2), a T1-weighted turbo spin-echo sequence, and a T2-weighted fat-suppressed turbo spin-echo sequence. After laparoscopic examinations, two observers independently reviewed the preoperative images. The DW images alone were reviewed first, followed by the conventional MR images alone and the conventional MR and the DW images together. The laparoscopic and MRI findings were compared. Sensitivity, specificity, and accuracy in the identification of nonpalpable undescended testes were calculated for DWI, conventional MRI, and the combination of DWI and conventional MRI.
The combination of DWI and conventional MRI was the most sensitive and most accurate technique. Observer 1 found 31 undescended testes, and observer 2, 30 testes with this technique. Sensitivity was 0.91 and 0.88 for observers 1 and 2, and accuracy was 0.92 and 0.86. With DWI alone, observer 1 located 30 testes, and observer 2, 28 testes (sensitivity, 0.88 and 0.82; accuracy, 0.86 and 0.81). Using conventional MRI alone, both observers located 29 testes (sensitivity, 0.85; accuracy, 0.86 and 0.84). The accuracy of locating testes was superior with the combination of DWI and conventional MRI for both observers (accuracy, 0.92 and 0.86). An intraabdominal atrophic testis managed by laparoscopic orchiectomy was found by neither observer with DWI or with conventional MRI.
Use of DWI with a high b value yields information that complements conventional MRI findings, improving identification and location of nonpalpable undescended testes. We recommend the use of conventional MRI in addition to DWI to increase the preoperative sensitivity and accuracy of identifying and locating nonpalpable testes.
本可行性研究旨在评估弥散加权 MRI 在评估不可触及未降睾丸中的作用。
36 名隐睾症男孩接受了术前腹部和骨盆 MRI 检查，以确定睾丸的位置。MRI 包括自由呼吸弥散加权成像（DWI），b 值分别为 50、400 和 800 s/mm2，T1 加权涡轮自旋回波序列，以及 T2 加权脂肪抑制涡轮自旋回波序列。腹腔镜检查后，两名观察者独立地对术前图像进行了回顾。首先单独对 DW 图像进行了评估，然后是单独的常规 MRI 图像，以及常规 MRI 和 DW 图像一起进行了评估。比较了腹腔镜和 MRI 的检查结果。计算了 DWI、常规 MRI 以及 DWI 和常规 MRI 联合应用在识别不可触及未降睾丸中的敏感性、特异性和准确性。
DWI 和常规 MRI 的联合应用是最敏感和最准确的技术。观察者 1 发现了 31 个未降睾丸，观察者 2 发现了 30 个睾丸。观察者 1 和 2 的敏感性分别为 0.91 和 0.88，准确性分别为 0.92 和 0.86。单独使用 DWI，观察者 1 定位了 30 个睾丸，观察者 2 定位了 28 个睾丸（敏感性分别为 0.88 和 0.82，准确性分别为 0.86 和 0.81）。单独使用常规 MRI，两位观察者均定位了 29 个睾丸（敏感性为 0.85，准确性分别为 0.86 和 0.84）。对于两位观察者来说，DWI 和常规 MRI 的联合应用在定位睾丸的准确性上均优于单独使用 DWI（准确性分别为 0.92 和 0.86）。两名观察者均未通过 DWI 或常规 MRI 发现腹腔镜下睾丸切除术治疗的腹腔内萎缩睾丸。
使用高 b 值的 DWI 可提供补充常规 MRI 发现的信息，从而提高不可触及未降睾丸的识别和定位。我们建议除了 DWI 之外，还应使用常规 MRI，以提高识别和定位不可触及睾丸的术前敏感性和准确性。
