多层螺旋CT对慢性胰腺炎并发假性动脉瘤的诊断价值

目的：探讨慢性胰腺炎并发假性动脉瘤的多层螺旋CT表现及CT诊断价值。方法：回顾性分析经手术、DSA及临床随访证实的9例慢性胰腺炎并发假性动脉瘤患者的CT资料,包括平扫、多期增强扫描横断面图像及后处理重组图像,重点分析假性动脉瘤的部位、形态、大小、密度、强化程度以及病灶与周围血管的关系。结果：9例假性动脉瘤患者中,发生于脾动脉者4例,位于胰体尾部区域;肠系膜上动脉1例,位于肠系膜上动脉走行区;胃十二指肠动脉及胰十二指肠动脉各2例,位于胰头区域。瘤体直径3.0～6.5cm,平均4.5cm。平扫病灶多呈稍低密度,圆形或类圆形;增强后病灶明显强化,动脉期瘤体内强化区域略低于或接近同层面主动脉CT值;门脉期接近或高于同层面主动脉CT值,6例延迟期扫描的病灶均呈相对高密度;病灶周边存在无强化区域。9例中3例可显示破口（33%）。结论：MSCT多期增强扫描结合图像后处理技术对慢性胰腺炎并发假性动脉瘤的定位、定性诊断具有重要价值。

Value of multi-slice spiral CT in the diagnosis of pseudoaneurysm associated with chronic pancreatitis

Objective：To discuss the imaging findings and values of multi-slice spiral CT （MSCT） in the diagnosis of pseudoaneurysm associated with chronic pancreatitis.Methods：9 cases of pseudoaneurysm complicating chronic pancreatitis proved by surgery,DSA or unequivocal clinical follow-up results were retrospectively reviewed about their CT manifestations with axial and post-processing images,and emphasis was focused on its location,shape,size,density,enhancement pattern and the relationship between lesions and vessels.Results：The pseudoaneurysm was located in the body or tail in 4 patients,in the region of superior mesenteric artery in 1 patient.and in the head of the pancreas in the remaining 4 patients.The bleeding arteries were respectively the splenic artery （4 cases）,superior mesenteric artery （1 case）,gastroduodenal artery （2 cases） and pancreaticoduodenal artery （2 cases）.Their size ranged from 3.0 to 6.5cm with a mean diameter of 4.5cm.On pre-contrast images,these lesions showed slightly low density with round or oval shape.During the arterial phase of post-contrast CT,these lesions exhibited marked enhancement which was below or similar to the CT attenuation value within the aorta, while density of pseudoaneurysm was slightly higher than or similar to the CT attenuation value within the aorta on portal venous phase.The lesions of 6 patients showed relatively high density during delayed phase and peripheral nonenhanced margin within the lesions were observed.The rupture of the pseudoaneurysms were correctly visualized in 33% of patients （3/9） on post-processing images.Conclusion：Multiple-phase scanning and the post-processing techniques with MSCT are of great value in the diagnosis of pseudoaneurysm associated with chronic pancreatitis.