急性胆囊炎

History

49-year-old man with a history of prior intrahepatic biliary stone disease and new onset of right upper quadrant pain

49岁男性，既往有肝内胆管结石病史，新发右上腹痛。

Fig 3.2.1：

Fig 3.2.2：

Fig 3.2.3：

Imaging Findings

Coronal SSFSE (Figure 3.2.1) and axial fat-suppressed SSFP

(Figure 3.2.2) images show moderate gallbladder wall thickening with mural edema and a gallstone in the gallbladder neck. Of note, a smaller stone, probably impacted in the cystic duct, and the bile fluid-fluid level can be seen on axial SSFP images. Axial postgadolinium 3D SPGR images (Figure 3.2.3) show irregular mucosal enhancement of the gallbladder wall, as well as patchy enhancement of the liver adjacent to the gallbladder fossa.

冠状位SSFSE序列(Figure 3.2.1)和横断位脂肪抑制SSFP序列(Figure 3.2.2)示胆囊壁中度增厚，囊壁水肿，胆囊颈部可见结石。另外，胆囊管内可见更小的结石，阻塞胆囊管。横断位SSFP序列示胆汁淤积，胆囊内可见液-液平面。

3D SPGR横断位增强扫描(Figure 3.2.3)示胆囊壁粘膜不规则强化，胆囊窝周围肝实质见斑片状强化。

Diagnosis

Acute cholecystitis

急性胆囊炎

Comment

MRI is not the primary imaging test for patients with right upper quadrant pain and suspected cholecystitis. US is much more readily available, is cheaper, and is reasonably accurate, and we certainly agree with the American College of Radiology Appropriateness Criteria for this indication, although the criteria lump MRI, CT with or without contrast medium, and scintigraphy as secondary options with equal validity (a questionable conclusion). Nevertheless, in cases where US is indeterminate or there are other potential diagnoses, MRI can be helpful. In this case,since the patient had known intrahepatic biliary stones, it was thought that MRI would be the more useful test.

对于右上腹痛、临床怀疑胆囊炎的患者，MRI并不是首选的影像学检查。美国放射学会适用标准认为超声检查经济、有效、准确，是影像学检查的首选，MRI、CT平扫或增强、闪烁扫描法有效性相同，可作为备选的检查（这一结论值得商榷）。

然而，当超声检查无法确诊，或存在其他可能性诊断时，MRI对诊断有一定的帮助。本例患者已知肝内胆管结石病史，MRI对诊断更有帮助。

Acute cholecystitis usually results from obstruction of the cystic duct or gallbladder neck by an impacted gallstone. Acalculous cholecystitis occurs in 5% to 10% of cases and may be incited by a gallbladder polyp, neoplasm, or adenomyomatosis. MRI findings in acute cholecystitis include impacted gallstones in the gallbladder neck or cystic duct, gallbladder wall thickening >3 mm, gallbladder wall edema, gallbladder distention (diameter>40 mm), pericholecystic fluid, and fluid around the liver. The presence of 1 or more of these 6 criteria was predictive of cholecystitis, with a sensitivity of 88% and specificity of 89% in 1 study. These results are dubious, however, because most of the criteria are nonspecific and have long differential diagnostic lists (ie, not all cirrhotic patients have acute cholecystitis), but in the appropriate clinical setting, they may be useful findings. We would also add to the list the presence of mucosal or mural enhancement, a near universal indication of inflammation. Hyperenhancement of the adjacent hepatic parenchyma, seen in this case, is a nonspecific finding but is suggestive of adjacent inflammation.

急性胆囊炎多由结石阻塞胆囊颈或胆囊管引起。结石所致胆囊炎发病率约5%-10%，可由胆囊息肉、肿瘤、胆囊腺肌瘤病刺激发病。MRI表现包括胆囊颈或胆囊管内结石嵌顿、胆囊壁增厚＞3mm、胆囊壁水肿、胆囊增大（直径大于40mm）、胆囊周围积液、肝周积液。

一项研究表明:满足上述6条胆囊炎诊断标准中的一项或多项，诊断敏感性88%，特异性89%。然而这一结果并不准确，因为上述的各项标准都没有特异性，需要与很多疾病鉴别诊断（例如，并非所有的肝硬化病人都有胆囊炎），只是在特定的临床条件下，这些表现有助于临床诊断。此外，胆囊壁或粘膜层的强化是胆囊炎症的普遍表现。

本例患者胆囊附近的肝实质也可见异常强化，这是一个非特异性征象，提示临近的肝实质炎症。

Another option in assessing patients with suspected cholecystitis is to use gadoxetate disodium(Eovist) and essentially perform the MR equivalent of nuclear scintigraphy. On hepatobiliary phase images, you should be able to see excreted contrast in the cystic duct andgallbladder. If you don’t,its absence implies obstruction of the cystic duct and cholecystitis.

对于怀疑胆囊炎的患者，钆塞酸二钠（Eovist）增强扫描也是影像学检查的选择之一，其检查的原理类似于核素的闪烁扫描。增强扫描的肝胆相位图像上，可以见到经胆囊和胆囊管排出的造影剂，如果没有看到造影剂排出，则提示胆囊管梗阻和胆囊炎。