MRI of the pancreas: tumours and tumour-simulating processes.
MRI of the pancreas: tumours and tumour-simulating processes.
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DOI：
10.1102/1470-7330.2006.0035
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发表时间：
2006-12-20
期刊：
影响因子：
--
通讯作者：
Schima, Wolfgang
中科院分区：
文献类型：
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作者：
Schima, Wolfgang
胰腺成像中最重要的问题是胰腺癌的检测和分期、癌症和局灶性胰腺炎的鉴别、囊性病变的表征以及神经内分泌肿瘤的寻找。应使用具有强梯度和相控阵躯干线圈的磁共振（MR）装置（1.5 T），使屏气成像成为可能，以避免运动伪影。标准成像序列是有或没有脂肪饱和的 T1 加权 (T1w) 梯度回忆回波 (GRE)。对于 T2 加权 (T2w) 成像，优选轴向单次涡轮自旋回波 (TSE) 和冠状/斜向 MR 胆管胰造影 (MRCP) 脉冲序列。使用钆剂或锰福地吡三钠作为造影剂。动态钆增强 T1w fatsat 3D GRE 图像有助于描绘腺癌的血管浸润并评估囊性肿块的病因。研究发现，在检测小癌症和描绘肝转移方面，锰福地吡增强 MRI 优于螺旋计算机断层扫描 (CT)。对于模棱两可的胰腺肿块，MRCP 中出现“导管穿透征”（即导管穿过肿块）提示存在炎性假瘤。由于局灶性脂肪浸润导致的低衰减可能类似于 CT 上的肿瘤，但同相和反相 T1w 成像很容易描绘脂肪。由于胰周血管的 3D 可视化，多排 CT 在胰腺成像中越来越受欢迎。然而，磁共振成像在描绘小胰腺肿瘤方面表现出色。由于其卓越的软组织对比度，MR 成像也是 CT 不明确患者的肿瘤与肿瘤模拟病症的鉴别诊断以及评估囊性病变的首选方法。
The most important issues in pancreatic imaging are the detection and staging of pancreatic cancer, differentiation between cancer and focal pancreatitis, the characterization of cystic lesions and the search for neuroendocrine tumours. Magnetic resonance (MR) units (1.5 T) with strong gradients and a phased-array torso coil should be used, making breath-hold imaging possible in order to avoid motion artifacts. Standard imaging sequences are T1-weighted (T1w) gradient recalled-echo (GRE) with and without fat saturation. For T2-weighted (T2w) imaging, axial single-shot turbo spin-echo (TSE) and coronal/oblique MR cholangio-pancreatography (MRCP) pulse sequences are preferable. As contrast agents either gadolinium agents or mangafodipir trisodium are used. Dynamic gadolinium-enhanced T1w fatsat 3D GRE images are helpful to delineate vessel infiltration by adenocarcinoma and to assess the aetiology of cystic masses. Mangafodipir-enhanced MRI has been found to be superior to helical computed tomography (CT) in the detection of small cancers and in the delineation of liver metastases. In cases of an equivocal pancreatic mass the presence of the "duct penetrating sign" at MRCP (i.e., the duct traversing the mass) is suggestive of an inflammatory pseudotumour. Hypoattenuation due to focal fatty infiltration may mimic a tumour at CT, but in-phase and opposedphased T1w imaging readily depicts the fat. Multi-detector CT has gained increasing popularity for pancreatic imaging because of the 3D visualization of the peripancreatic vessels. However, MR imaging is excellent in the delineation of small pancreatic tumours. Due to its superior soft tissue contrast, MR imaging is also the method of choice in the differential diagnosis between tumours and tumour-simulating conditions in patients with equivocal CT and to assess cystic lesions.