ObjectiveTo explore the characteristic CT features of benign and malignant submandibular gland lesions.Methods CT scans of 75 cases of submandibular gland lesions verified pathologically after surgery were analyzed retrospectively,including 38 cases of pleomorphic adenoma,22 cases of malignant tumors,11 cases of chronic submaxillaritis,2 cases of myoepithelioma,1 case of neurilemoma and 1 case of hemangioma.Results ( 1 ) All 38 cases of submandibular gland pleomorphic adenoma only occupied a part of submandibnlar gland.Thirty five lesions were on the edge of submandibular gland.The edge of 33 lesions were smooth and the density of 30 lesions were even.Thirty three lesions were slightly or moderately enhanced and 10 lesions showed “target sign” on enhanced CT.( 2 ) There were 22 cases of submandibular gland malignant tumors.Three lesions of lymphoma located at the edge of submandibular gland with smooth edge and even density,and showed mild to moderate enhancement.The remaining 19 lesions showed rough edge and uneven density.Eighteen of the 19 lesions showed ill-defined boundary,2 of the 18 lesions invaded most of submandibular gland and 16 of the 18 lesions invaded the whole submandibular gland.Seventeen lesions were unevenly enhanced,thickened,cirvilinear vessels were seen in 12 of the 17 lesions.Nine cases were accompanied with swollen lymph nodes ( minor diameter greater than 1.0 cm) in neck.(3)There were 11 cases of chronic submaxillaritis,which showed enlargement of the whole submandibular gland with relative smooth edge and relative clear boundary.Most of lesions were moderately and evenly enhanced.Six cases were companied with submandibular duct lithiasis and dilatation.All of 11 cases were accompanied with lymph node enlargement in neck.(4) Two cases of myoepithelioma demonstrated irregular ring enhancement on CT;one case of neurilemoma showed obvious cystic changes and slight enhancement on the edge;1 case of hemangioma showed multiple phleboliths and prolonged contrast enhancement.ConclusionsMost of submandibular gland benign and malignant lesions show some degree of characteristic CT findings.It is relatively difficult to discriminate between lymphoma and submandibular gland pleomorphic adenoma.

Objective To study the CT findings of small thyroid carcinoma. Methods The CT findings of 40 patients with histology-proven small thyroid carcinoma (diameter, 1.0 to 2. 0 cm) were retrospectively reviewed. Results (1)The single lesion was detected in 38 cases and two lesions in bilateral thyroid in 2 cases. Two cases were combined with contralateral nodular goiter and I case with contralateral thyroid adenoma. ( 2 ) Eight lesions showed smooth edge and complete envelope. Thirty-four lesions demonstrated foggy edge and incomplete envelope,but they didn't invade the surrounding soft tissues and important organs. ( 3 ) The density of all lesions were homogeneous or comparatively homogeneous without obvious hemorrhage or necrosis area on non-enhanced CT. Thirty lesions showed varied shape calcifications,with granular calcifications in 20 lesions being the most common. Irregular nodular,eggshell-like or mulberrylike calcifications were also detected. (4)Forty-one lesions showed marked enhancement on post-contrast CT and the amplitude of enhanced CT value was greater than 40 HU(range,90 to 140 HU). Thirty-eight lesions exhibited homogeneous enhancement, and other 3 lesions showed marked enhancement center with a ring-like low density edge and manifested as a characteristic damascene-like appearance. (5)Enlarged cervical lymph nodes were found in 24 cases ( 60. 0% ), which displayed solid, cystic-solid or cystic appearances on nonenhanced CT. They showed markedly homogeneous,irregular ring or wall-node enhancement on post-contrast CT. In 8 cases there were granular, nodular or eggshell-like calcifications within the enlarged lymph nodes.Conclusion A solid thyroid nodule with granular calcification, incomplete envelope and marked enhancement, companied with enlarged lymph nodes with calcification, cystic degeneration and obviously enhanced solid part are the relatively characteristic CT features of small thyroid carcinoma.

Objective To explore the CT and MR imaging findings of acinic cell carcinoma (ACC)in salivary gland and enhance the diagnosis of this rare disease.Methods The CT and MR imaging characteristics of 20 patients (7 males and 13 females,median age 44 years old) with pathologically proved ACC were retrospectively reviewed.CT and MR images were evaluated in relation to the following: location,size,morphology,margin,CT density/MR signal intensity and enhancement pattern.Results Twelve lesions were located in parotid gland,two lesions in maxillary Sinus,and one lesion in submandibular,parapharyngeal,infratemporal fossa,buccal,nasal cavity,and hard palate respectively.The size of lesions were 0.7～5.8 cm.Sixteen lesions less than 3 cm in size demonstrated round or oval round masses with well defined margin.Four lesions more than 3 cm in size demonstrated irregular masses with unclear margin.Among them,bony destruction of the wall of the maxillary sinus was noted in 3 cases,and the preauricular skin was invaded in 1 case.The densities (signal intensity) were homogeneous in 6 cases and heterogeneous in 14 cases.Lesions were slightly low density in 11 case and isodensity in 3 cases on CT plain scan.Lesions were homogeneous isointense in 2 cases and heterogeneous isointense in 4 cases on T1WI,heterogeneous hyperintense in all cases on T2WI.On post contrast images,lesions demonstrated remarkable enhancement in 14 cases,moderate enhancement in 2 cases and mild enhancement in 3 cases.Conclusions The imaging characteristic of ACC were nonspecific.CT and MR could accurately detect the extent of tumor involvement and was helpful to provide more comprehensive information for the strategy of clinic therapy.

Objective To improve the clinic,CT and pathologic knowledge of pleomorphic hyanilizing angiectatic tumor of soft parts(PHAT).Methods Clinical,CT and pathologic characters of PHAT in one case at the right nuchal region were detailedly analysed with literature review.Results The clinical symptoms of PHAT were slight and unspecified.The lesion appeared as a orbicular-ovate tumour with sublobe and clear edge,the density of tumor was uneven on plain scan and uneven enhanced after injected contrast agent,and a part of the tumour was enhanced close to the CT value of blood vessel.The characters of pathology were the presence of clusters of dilated thin-walled vessels,with prominent hyalinization of vessel wall,perivascular and intercellular hyalinization,and pantomorphia neoplastic cell distributed between these dilated vessels.Conclusion PHAT is a low potential malignant soft tissue tumor,it has some specific CT and pathologic characters.

Objective To study the clinicopathological features in the diagnosis of serous microcystic adenoma of pancreas.Method A clinicopathological and immunohistochemical study was conducted on 7 patients with serous microcystic adenoma of pancreas.Results All the patients were female,with a mean age of 51 years.Clinical symptoms were present in 2(28.6％)patients.On microscopy,the tumor composed of variable-sized cysts.The cyst wall was covered by simple cuboidal epithelium.The cytoplasm was clear and glycogen-rich.The nucleus of the epithelial cells was small and round.In the center,there was no nucleolus and no nuclear division.There were bulky fibrous tissues between the cystic cavities.Immunohistochemical study showed AE1/AE3,CK7,CK8,CK19,CK/LMW,EMA were positive,and CEA,CD31,CD34,D2-40,Syn,CgA,Calretinin,Vim were negative.Conclusions Serous microcystic adenoma of pancreas is a rare tumor,which was common in old women.Serous microcystic adenoma of pancreas is a benign tumor with good prognosis.The diagnosis is made on histopathological and immunohistochemical study.

OBJECTIVETo assess the diagnostic value of dual energy CT for lymph node metastasis in patients with non-small cell lung cancer (NSCLC).

METHODSForty NSCLC patients, including 15 cases of squamous cell carcinoma and 25 cases of adenocarcinoma, underwent dual energy CT examination in pre-contrast and venous phase contrast scans, then the CT attenuation value of the lung cancer lesions and 85 mediastinal enlarged lymph nodes (the short diameter ≥ 5 mm, 53 metastatic and 32 non-metastatic) were measured at different energy levels (40-190 keV, spacing 10 keV) in venous phase contrast. CT spectral curves of the lung cancer lesions, hilus pulmonis and mediastinal enlarged lymph nodes were produced automatically, through comparing their CT spectral curves slope to judge whether or not the lymph nodes were metastatic. Receiver operating characteristic (ROC) curve was used to evaluate the efficiency of CT spectral curve in diagnosis of lymph node metastasis.

RESULTSThe CT spectral curves slopes of the lung cancer, metastatic lymph nodes and non-metastatic lymph nodes were 1.10±0.11, 1.08±0.07 and 1.54±0.17, respectively. There was no significant difference in curve slope between metastatic lymph nodes and lung cancer (=-1.32,>0.05); while there was significant difference between non-metastatic lymph nodes and lung cancer (=-2.58,<0.05). The CT spectral curve slope ratios of metastatic and non-metastatic lymph nodes to lung cancer were 0.98±0.05 and 1.40±0.12, respectively (=-2.86,<0.05). ROC curve showed that taking CT spectral curve slope ratio of 1.15 as cut-off value for the diagnosis of metastatic lymph nodes, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 81.1%, 87.5%, 91.5%, 73.7% and 83.5%, respectively.

CONCLUSIONSDual energy CT is of value in improving the diagnostic accuracy of lymph node metastasis in NSCLC patients before treatment.