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脾脏的大体及断面解剖.2 .脾脏的先天变异( 位置、形态及数目) .3 .脾感染性疾病:脾脓肿,脾结核及脾包虫病.CT、MRI 均表现病灶中心为低密度液化坏死区,边缘可见环行强化.病灶多发及钙化有助于脾结核的诊断.4 .脾脏的囊性病变:主要包括脾囊肿、脾内假性胰腺囊肿及脾包虫病.CT、MRI 像呈液性密度或信号,边缘光整.鉴别诊断需结合临床病史及包虫皮试.5 .脾良性肿瘤:主要包括脾血管瘤,脾错构瘤和淋巴管瘤.以脾血管瘤最多见,较特征性的影像学表现为CT 增强扫描病灶明显强化,MRI T1 W 像呈低信号或等信号,T2 W 像呈高信号.6 .脾脏恶性肿瘤:常见有恶性淋巴瘤和转移瘤.恶性淋巴瘤CT 表现为脾肿大,脾内多发或单发低密度灶,边缘不规整.脾转移瘤表现多种多样,病灶可单发或多发,实性或囊性.MRI呈稍长T1 、T2 信号.7 .脾梗塞:常见于脾血管血栓、癌栓栓塞及肿瘤组织的包埋.典型梗塞形状为尖端指向脾门、内小外大的锥形.CT 增强扫描为低密度灶.MRI 呈稍长T1、长T2 信号.8 .脾外伤包括三种:a 完全性破裂;b 脾中心破裂;c 包膜下破裂.CT、MRI 可显示脾损伤裂口,还可区分新鲜、陈旧出血及腹腔积液等.“,”The gross and cross-sectional anatomy of spleen.2. Splenic Anatomical variations in quantity, localization and shape.3. Inflammatory splenic disease:Abscess, tuberculosis and hydatidosis are commonly seen. On contrast enhanced CT, abscess typically shows contrast-enhancing wall and central low density representing necrosis. Multiplicity and calcification are more inclined to suggest tuberculosis.4. Cystic splenic disease:This kind of splenic lesions mainly include cyst, pancreatic pseudocyst and hydatidosis. With CT and MRI, Cyst is seen as localized lesion with smooth borderline and attenuation or intensity similar to fluid. The differential diagnosis needs combining with clinical history and hydatid skin test.5. Benign tumors:The three most important benign tumors of the spleen are hemangioma, hamartoma and cystic lymphangioma. Hemangiomas are the most frequently seen and uaually show characteristic imaging features. On enhanced CT, most hemangiomas exhibit obvious enhancement and on MRI show low or equal intensity on T 1 WI and high intensity on T 2 WI.6. Malignant tumors:Malignant lymphoma and metastasis are the commonest malignant tumors of the spleen. On CT, malignant lymphoma of spleen shows splenomegaly and single or multiple lesions with low density and irregular borders. Metastatic deposits may be solitary or multiple and vary in size, shape and density. On MRI, there may be slightly prolonged T 1 and T 2 relaxation time. 7. Infarction:Splenic infarctions are usually caused by thrombo-embolic occlusions of splenic arteries or tumor encasement of splenic vessels. Typical splenic infarction shows as a wedge-shaped lesion with the tip pointing to the splenic hilum. On CT, it is hypodenses and on MRI, T 1 and T 2 relaxation time are slightly increased. 8. Trauma:Splenic injuries can be divided into 3 types: complete rupture, central rupture and subcapsular rupture. CT and MRI can not only demonstrate the injury site, but also characterize new bleeding, old bleeding or ascites.