Jang Kyung Mi, Kim Seong Hyun, Park Hyun Jeong, Lim Sanghyeok, Kang Tae Wook, Lee Soon Jin, Choi Dongil
Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Acta Radiol. 2013 Dec;54(10):1107-16. doi: 10.1177/0284185113491251. Epub 2013 Jul 15.
Ectopic pancreas can frequently be mistaken for other submucosal masses. Ectopic pancreas may follow the signal intensity of mother pancreas on various magnetic resonance (MR) sequences, which might be helpful for differentiation between ectopic pancreas and other submucosal tumors in upper gastrointestinal (UGI) tract.
To evaluate the value of MR imaging (MRI) in differentiating ectopic pancreases from submucosal tumors in UGI tract.
Fifteen patients with ectopic pancreas and 26 patients with UGI submucosal tumors were included. All patients underwent abdominal MRI with diffusion-weighted imaging (DWI) and gadoxetic acid-enhanced MRI. Qualitative (location, contour, growth pattern, lesion border, and presence of intralesional cystic portion and duct-like structure) and quantitative (long diameter [LD], short diameter [SD], LD/SD ratio, signal intensities and apparent diffusion coefficients [ADC], and signal intensity - and ADC ratios of UGI submucosal lesions to pancreas) parameters were compared between ectopic pancreases and UGI submucosal tumors using Fisher's exact test, the Mann-Whitney U test, and receiver-operating characteristic (ROC) analysis.
Duodenum was the most common location for ectopic pancreas (12/15, 79.9%), and the gastric body for UGI submucosal tumors (15/26, 57.7%) (P = 0.005). Round shape was an imaging feature more common in UGI submucosal tumors (12/26, 46.2%) than in ectopic pancreas (1/15, 6.7%; P = 0.021). On all of the various pulse sequences of MR images, ectopic pancreas showed isointensity comparable to that of pancreas more frequently than did sequences of UGI submucosal tumors (P < 0.01).The means (0.95 ± 0.09, 0.99 ± 0.06, 1.07 ± 0.08) of the signal intensity ratio of ectopic pancreas to pancreas on fat-suppressed unenhanced T1-weighted, arterial, and portal phase images were significantly higher than those (0.60 ± 0.09, 0.62 ± 0.28, 0.86 ± 0.27) of UGI submucosal tumors (P < 0.05). In contrast, the means (1.05 ± 0.12, 0.93 ± 0.18) of the signal intensity ratios of ectopic pancreas on T2-weighted images and DW images (b = 800 s/mm(2)) were significantly lower than those (1.82 ± 0.39, 2.35 ± 0.94) of UGI submucosal tumors (P < 0.001). On ROC analysis, if absolute value of difference between 1.0 and signal intensity ratio of submucosal lesions to the pancreas on T1-weighted images is <0.21, the sensitivity and specificity reach 100.0% for diagnosis ectopic pancreas from submucosal tumors.
Abdominal MRI with DWI can be a valuable tool for differentiating ectopic pancreases from UGI submucosal tumors.
异位胰腺常被误诊为其他黏膜下肿物。异位胰腺在各种磁共振（MR）序列上可能呈现出与母胰腺相同的信号强度，这可能有助于鉴别上消化道（UGI）中的异位胰腺与其他黏膜下肿瘤。
评估MR成像（MRI）在鉴别UGI中的异位胰腺与黏膜下肿瘤方面的价值。
纳入15例异位胰腺患者和26例UGI黏膜下肿瘤患者。所有患者均接受了腹部MRI检查，包括扩散加权成像（DWI）和钆塞酸增强MRI。采用Fisher精确检验、Mann-Whitney U检验和受试者操作特征（ROC）分析，对异位胰腺和UGI黏膜下肿瘤的定性（位置、轮廓、生长方式、病变边界以及病灶内囊性部分和导管样结构的存在情况）和定量（长径[LD]、短径[SD]、LD/SD比值、信号强度和表观扩散系数[ADC]，以及UGI黏膜下病变与胰腺的信号强度和ADC比值）参数进行比较。
十二指肠是异位胰腺最常见的部位（12/15，79.9%），而胃体是UGI黏膜下肿瘤最常见的部位（15/26，57.7%）（P = 0.005）。圆形是UGI黏膜下肿瘤比异位胰腺更常见的影像学特征（12/26，46.2%比1/15，6.7%；P = 0.021）。在MR图像的所有不同脉冲序列上，异位胰腺比UGI黏膜下肿瘤序列更频繁地显示出与胰腺相当的等信号（P < 0.01）。脂肪抑制未增强T1加权、动脉期和门静脉期图像上异位胰腺与胰腺的信号强度比值均值（0.95±0.09、0.99±0.06、1.07±0.08）显著高于UGI黏膜下肿瘤的均值（0.60±0.09、0.62±0.28、0.86±0.27）（P < 0.05）。相比之下，T2加权图像和DWI图像（b = 800 s/mm(2)）上异位胰腺的信号强度比值均值（1.05±0.12、0.93±0.18）显著低于UGI黏膜下肿瘤的均值（1.82±0.39、2.35±0.94）（P < 0.001）。在ROC分析中，如果T1加权图像上黏膜下病变与胰腺的信号强度比值与1.0之间的差值绝对值<0.21，则从黏膜下肿瘤诊断异位胰腺的敏感性和特异性可达100.
