胰腺异位副脾的CT与MRI检查特征

Computed tomography and magnetic resonance imaging features of intrapancreatic accessory spleen

  • 摘要: 胰腺异位副脾(IPAS)临床少见,其影像学表现易与胰腺实质性肿瘤相混淆,总结其CT和MRI检查特征,将有助于提高对该病的诊断与鉴别诊断水平,避免不必要的手术。2007年8月至2012年8月宁波大学医学院附属医院和第二军医大学长海医院分别收治的5例和3例IPAS患者。8例患者均行CT检查。7例患者同时行MRI检查,其中5例行磁共振弥散加权成像(DWI)检查。其结果显示:8例患者病灶均位于胰尾,4例呈卵圆形,3例呈类圆形、1例呈类三角形,最长径为(2.3±1.0)cm,最短径为(1.4±0.6)cm。CT平扫:8例患者病灶密度与原位脾相近。CT增强扫描检查:动脉期:3例患者病灶呈均匀强化,5例患者病灶呈斑马纹样强化;门静脉期:8例患者病灶强化程度趋向均匀;延迟期:8例患者病灶强化程度均下降。三期动态增强扫描中,8例患者病灶强化方式与原位脾基本一致,7例患者病灶强化程度高于胰腺实质。MRI检查:7例患者病灶在T1WI、T2WI的信号强度与原位脾一致;在动态增强扫描各期6例患者病灶强化程度均高于胰腺实质。DWI检查:b=600 s/mm2时,病灶呈显著高信号,ADC600值为(0.868±0.046)mm2/s,与相应原位脾的ADC600值(0.870±0.045)mm2/s比较,差异无统计学意义(t=0.522,P>0.05)。2例患者合并肝硬化,其中1例伴原发性肝癌。2例患者发现脾脏周围存在其他副脾。因此,当影像学检查发现胰尾的类圆形或卵圆形病灶边界清楚,其密度、信号强度与脾脏相近时应考虑IPAS。CT和(或)MRI动态增强扫描联合DWI检查对IPAS的诊断具有重要价值。

     

    Abstract: Intrapancreatic accessory spleen (IPAS) is rarely seen in clinical practice. Its imaging presentation was similar to that of the pancreatic solid tumor. Familiarity with the computed tomography (CT) and magnetic resonance imaging (MRI) features is helpful for the diagnosis and treatment of IPAS, and thus avoid unnecessary operations. From August 2007 to August 2012, 5 patients with IPAS were admitted to the Affiliated Hospital of Ningbo University and 5 patients to the Changhai Hospital. All the 8 patients underwent CT scan. Seven patients received concomitant MRI examination [5 patients received diffusion weighted imaging (DWI)]. The IPAS of 8 patients were located at the tail of pancreas (the shapes of 3 cases were round, 4 were oval and 1 was triangular). The longest diameter was (2.3±1.0) cm and the shortest diameter was (1.4±0.6) cm. The results of CT plain scan showed that the density of the IPAS of the 8 patients was similar to that of the orthotopic spleen. The results of artery phase of the enhanced CT showed zebra patterns enhancement in 5 patients, and homogenous enhancement in 3 patients. The results of venous phase of the enhanced CT showed remarkable high signal intensity consistent with spleen, and the signal intensity decreased gradually in the delayed phase. The patterns of enhancement of the lesions were similar to those of orthotopic spleen in 8 patients, and the lesions of 7 patients had higher signal intensity than those of pancreatic parenchyma. The signals of 7 patients in T1 weighted images and T2 weighted images were similar to those of orthotopic spleen. On DWI images (b=600 s/mm2), IPAS showed remarkable high signal intensity, and the ADC600 value was (0.868±0.046)mm2/s, which showed no significant difference compared with (0.870±0.045)mm2/s of the orthotopic spleen (t=0.522, P>0.05). Two patients were complicated with hepatic cirrhosis, and 1 of them was with concomitant primary liver cancer. Other accessory spleens around the orthotopic spleen were found in 2 patients. In conclusion, IPAS has similar characteristics to those of the spleen on both the precontrast and contrast-enhanced images of all imaging modalities. CT and MRI combined with DWI examination have great value in diagnosing IPAS.

     

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