Objective To summarize CT features , benign and malignant differential main points of the tumors of germ cell origin in the mediastinum.Methods 32 cases with pathologically confirmed the tumors of germ cell origin in the mediastinum were retrospectively analysed.Results Of 32 cases,26 were benign tumors,including cyst mass in 10,solid mass in 9 and cyst-solid mass in 7.6 cases were malignant tumors, including seminoma in 1 ,endodermal sinus tumor or yolk sac tumor in 1,embryo cell casinoma in 1 and malignant teratoma in 3 .Typical benign teratoid tumors appeared as water to soft tissue density masses,with defined margin,fat or calcification inside the tumors,around tissues were compresed by tumors,the malignant tumors appeared as lobular or irregular masses and around organ invaded.Conclusion CT is a reliable method for the diagnosis of the tumors of germ cell origin in the mediastinum accurately.Malignant tumors of germ cell origin in the mediastinum are difficult differentiation from other mediastinal malignant tumors.

Objective To explore the imaging features of primary bone tumors and tumor-like lesions of the skull,so that to improve the diagnostic accuracy of the disease.Methods 47cases with bone tumors and tumor-like lesions of the skull confirmed by pathology or typical imaging manifestations were retrospectively analysed.Results Of 47 cases,there were benign tumors in 22 cases,malignant tumors in 6 cases and tumor-like lesions in 19 cases.Benign tumors included osteoma of 11cases,epidermoid tumor and cyst of 4 cases,osteochondroma and neurofibromatosis of 2 cases respectively,carvernous angioma ,osteoid osteoma,and benign fibrohistiocytoma of 1case respectively.Malignant tumors included multiple myeloma and angiosarcoma of 2 cases respectively,Ewing’s tumor and osteosarcoma each and all in 1 case .Tumor-like lesions included fibrodysplasis of bone in 8 cases, Langerhans’ cell histiocytosis in 7 cases ,brown tumor and deformed osteitis each and all in 2 cases.Conclusion Primary bone tumor and tumor-like lesions of the skull are of a great variety,each one has its own imaging characteristics,the diagnosis of them should be combined with clinic and pathologic data.

Objective To study the imaging value in diagnosis of congenital cholangiectasis.Methods The clinical and imaging (CT and ultrasonics) data of 6 patients with congenital cholangiectasis were restrospectively analyzed with literature review.Results According to Todani's classifications of cholangiectasis,there were type I in one case,CT showed cystic hypodense shadow with thin and smooth wall;type IV in 4 cases,CT showed cystic or fusiform extension of intra-and extra-hepatic bile ducts;type V in one case,CT showed cystic extension of intra-hepatic bile ducts,and the central spot enhancement could be seen on contrast-enhanced CT scan.6 cases underwent ultrasonic examinations,ultrasound showed extension of intra-and extra-hepatic bile ducts in 6 cases,choledochal cyst in one.4 cases suspected with congenital cholangiectasis,and misdiagnosed in one.In company with cholecystitis and cholelithiasis in one,biliary carcinoma in one and cirrhosis in one.Conclusion CT and US are of important value in diagnosis of congenital cholangiectasis.