Feuerlein Sebastian, Pauls Sandra, Juchems Markus S, Stuber Tina, Hoffmann Martin H K, Brambs Hans-Juergen, Ernst Andrea S
Department of Diagnostic and Interventional Radiology, University of Ulm, Steinhoevelstrasse 9, 89075 Ulm, Germany.
AJR Am J Roentgenol. 2009 Oct;193(4):1070-6. doi: 10.2214/AJR.08.2093.
As diffusion-weighted imaging is increasingly implemented into routine protocols of abdominal MRI, abnormal findings in expected and unexpected locations become more common. The aim of our retrospective study was to investigate the specificity of restricted diffusion in differentiation of benign from malignant abdominal disease.
Two hundred thirty consecutively registered patients underwent abdominal MRI including diffusion-weighted imaging (single-shot spin-echo echo-planar sequence) with b values of 0, 150, 500, and 1,000 s/mm(2). Lesions were detected by two blinded readers using only the images with a b value of 1,000 s/mm(2), and representative apparent diffusion coefficients were measured. Lymph nodes were not documented.
Fifty-two of the 230 patients had a total of 55 lesions with restricted diffusion (23.9%). The mean apparent diffusion coefficient was 809 mm(2)/s. Forty-three lesions (78.2%) were malignant. The 12 benign lesions were liver hemangioma, liver adenoma, autoimmune pancreatitis, pancreatic teratoma, two abscesses, three cases of inflammatory bowel wall thickening due to Crohn's disease, Bartholin cyst, hemorrhagic ovarian cyst, and renal Rosai-Dorfman disease.
Restricted diffusion is generally considered to be associated with malignant tumors because of the high cellularity of these tumors. However, in interpretation of diffusion-weighted images, it should be kept in mind that a number of benign lesions, as many as 22% in our cohort, can exhibit restricted diffusion on images with high b values, thus mimicking malignant lesions.
随着扩散加权成像越来越多地应用于腹部MRI的常规检查方案中，在预期和非预期部位出现的异常表现变得更加常见。我们这项回顾性研究的目的是探讨扩散受限在鉴别腹部良性与恶性疾病中的特异性。
230例连续登记的患者接受了腹部MRI检查，包括扩散加权成像（单次激发自旋回波平面回波序列），b值分别为0、150、500和1000 s/mm²。两名阅片者在不知情的情况下仅使用b值为1000 s/mm²的图像检测病变，并测量代表性的表观扩散系数。未记录淋巴结情况。
230例患者中有52例共有55个病变表现为扩散受限（23.9%）。平均表观扩散系数为809 mm²/s。43个病变（78.2%）为恶性。12个良性病变包括肝血管瘤、肝腺瘤、自身免疫性胰腺炎、胰腺畸胎瘤、2个脓肿、3例克罗恩病所致的炎症性肠壁增厚、巴氏腺囊肿、出血性卵巢囊肿和肾罗萨伊-多夫曼病。
由于恶性肿瘤细胞密度高，扩散受限通常被认为与恶性肿瘤有关。然而，在解读扩散加权图像时，应牢记在我们的队列中有多达22%的一些良性病变在高b值图像上可表现为扩散受限，从而酷似恶性病变。
