Objective To improve the diagnosis and differential diagnosis of mediastinal cysts.Methods 36 patients with mediastinal cyst proved by surgery and pathology were collected, and CT findings were analyzed retrospectively.Results In all 36 cases,CT defined the masses with clear margin, thin wall and fluid-like density content which had no enhancement after intravenous contrast administration. There were neurenteric cyst(n=1), bronchial cyst(n=12), esophageal cyst(n=2), pericardial cyst(n=5), dermoid cyst(n=7), lymphangioma(n=4), thymic cyst(n=4) and non-special cyst(n=1). Conclusion The diagnosis of mediastinal cyst and differential diagnosis from other cystic lesions can be made according to the characteristics on plain and post-contrast CT scans.

Objective To study the CT features and enhance the knowledge of peripheral primitive neuroectodermal tumors(pPNETs). Methods The CT appearances of 6 patients with pPNETs pathologically proved were analyzed retrospectively. Results The CT findings of 5 bone pPNETs were soft mass of homogeneous or heterogeneous density and osteolytic destruction without osteosclerosis, periosteum reaction and tumor bone formation. Follow up CT showed the mass shrunken significantly after radiotherapy in one case. In 1 patient of chest Askin tumor, the lesion appeared as a vast heterogeneous soft mass with moderate inhomogeneous enhancement. The mass invaded mediastinum and local bone destruction were not detected. Four months after operation, a small homogeneous tumor occurred in right chest wall with moderate homogeneous enhancement. Conclusion The manifestations of pPNETs on CT have no characteristics. However, CT can show the intra tumor structures and the extent of the tumor very well, which is helpful in differentiating diagnosis,predicting resectability, detecting distant metastases and evaluating the response to treatment.

Objective To study the CT appearances of primary pulmonary histoplasmosis (PPHP)and evaluate the diagnostic values of CT for PPHP.Methods The clinical materials and multi-slice spiral CT appearances in 8 patients with PPHP proved pathologically were reviewed retrospectively.Results Single or multiple pneumonia-like lesions were seen in 3 esses,single or multiple nodules or masses were in 4 cases,and both pneumonia-like lesions and nodules or mflsses in 1 case.Calcification and halo sign were common,and only slight enhancement was demonstrated after intravenous contrast administration on CT.Conclusion CT is helpful imaging method in the diagnosis and differential diagnosis of PPHP combining with clinical materials although the CT appearances are not specific.

Objective To study the imageological findings and the evolution of pulmonary alveolar microlithiasis(PAM). Methods The clinical and imageological information of 3 siblings suffering from PAM were collected, and their imageological findings and changes in follow-up plain radiographs were analyzed retrospectively. Results On chest radiographs, the typical “sandstorm” pattern was shown in all 3 cases. The severity and extent of microliths and interstitial fibrosis were increased with age and clinical course by comparing with the radiographs 24 years ago. On conventional CT, bilateral diffuse micronodules in parenchyma were demonstrated with pulmonary window in 3 cases, concentrating in the subpleural zones of middle and lower lung fields and the areas around bronchovascular bundles. All were associated with various degrees of fibrosis. The nodules and calcifications were visible in both lungs with mediastinal window, forming so-called flame sign and white line sign in the concentrated areas. The extents and degrees of the microliths, small cysts and interstitial fibrosis were revealed more clearly and truly on HRCT. MRI showed diffusely increased signal intensity on T 1WI and lower signal intensity on T 2WI in both lung fields. Conclusion The chest radiograph was still an initial modality in detecting the disease. CT could comprehensively reveal the pathological status of the PAM and played a decisive role in the diagnosis and differential diagnosis. MRI had only limited value in evaluating the condition.

Objective To investigate the CT manifestations of pulmonary sclerosing hemangioma (PSH), and improve the CT diagnostic accuracy of the disease.Methods The CT manifestations of 5 cases with pulmonary sclerosing hemangioma which were proved by pathology were analyzed retrospectively. Results Solitary pulmonary nodule was demonstrated in all 5 cases with clear demarcation on CT. The nodule was smooth and homogeneous in density in 4 cases, and was slightly irregular with cavity in another case. After intravenous contrast administration, all the lesions were homogeneously enhanced, similar to the nearby blood vessels. The vessels linked with the lesions were found generally.Conclusion The CT is helpful for the diagnosis of PSH.

Objective To compare the conventional non-enhanced and virtual non-enhanced images of dual-energy computed tomography (CT) in evaluating solitary pulmonary nodules (SPNs).Methods Forty-seven patients with SPNs proved by pathology underwent conventional and enhanced thoracic DECT.The virtual non-enhanced CT images and iodine images were reconstructed based on the enhanced imaging data.The mean CT number,noise,signal to noise (SNR),nodual diameter of SPNs were compared between the true non-contrast CT(TNCT) and the virtual non-contrast CT (VNCT),with paired t test.The image quality and detectability of calcification were also compared.The diagnostic accuracy for malignant nodulesbased on the increased CT values and iodine-enhanced image were compared.The independent t test was used to compare the increased CT number of SPNs and iodine images.The single-phase radioation dose of the single energy,was compared with dual energy scan.Results No significant difference in the mean CT Number(t =1.556,P ＞ 0.05),noise (t =-0.357,P ＞ 0.05),SNR (t =0.767,P ＞ 0.05) on TNCT and VNCT.The mean CT Number,the noise,and SNR were (29.90 ± 12.43)vs (27.52 ± 16.67) HU,(9.60 ±3.74) vs (9.88 ± 2.90),and (3.07 ± 1.93) vs (2.76 ± 2.36),respectively.The increased CT number ofSPNs with TNCT and VNCT from baseline were(18.63 ± 8.03) and(20.45 ± 9.13) HU.The CT number of iodine image was(23.82 ± 9.20)HU.A significant difference was observed between the TNCT and iodineed image (t =-2.371,P ＜ 0.05).The quality scores of VNCT image wasslightly worse than TNCT image.The detectability rate of calcification on VNCT was 92.3％ (72/78).The iodine image carried the highest diagnostic sensitivity rate and accuracy rate,82.3％ (28/34)and 74.5％ (35/47),respectively.The highest specificity rate was 76.9％ (10/13) from the increased CT number with VNCT.No significant difference in single-phase radiation dose was observed between TNCT and VNCT,(5.68 ± 1.31) vs.(4.89 ± 1.27)mSv.Conclusions VNCT could be obtained with similar image quality as TNCT.This methods might favor a reduction in radiation exposure.

Purpose To explore the diagnostic value of multiple image technique derived from dual-energy CT in arterial+parenchymal phase scan mode in detecting pancreatic adenocarcinoma so as to provide more valuable information for clinical treatment.Materials and Methods Thirty two patients with pancreatic adenocarcinoma proved pathologically underwent dual-phase scan with dual-source CT.Linear blend image,non-linear blend image and iodine map were acquired.The absolute enhancement value of tumor (AEV),the relative enhancement value of tumor (REV),enhancement ratio (ER) of tumor to pancreatic parenchyma,and the image contrast to noise ratio (CNR) were also calculated,so that the diagnostic value and the ability image in two phases to display the pancreatic adenocarcinoma lesions could be assessed.Results On arterial phase,the differences in AEV,REV and CNR value were significant among the three groups images (P＜0.05).On parenchymal phase,the difference in REV,ER,and CNR value were also significant among the three groups (P＜0.05).When the three sequences on the 2 phases were compared with each other,the differences in AEV and REV value of tumor tissues were significant among the groups (P＜0.05).Moreover,the differences of ER value in linear blend image and CNR in the iodine map were significant in dual phase enhancement (P＜0.05).Conclusion Dualenergy CT enhanced scan mode on dual phase combined with multiple sequences can improve the sensitivity in detection of pancreatic adenocarcinoma lesions.

Objective To observe the clinical value of application of low-dose scanning technology in dual source CT coronary angiography.Methods 200 cases who received coronary artery imaging were randomly selected as the study subjects.Patients were divided into the observation group and the control group using the random number method,100 cases in each group.All patients underwent dual source CT angiography.The observation group was treated by adaptive prospective ECG gated sequence,the control group was treated with retrospective ECG gated sequences.The image quality and radiation dose to bear were compared between the two groups.Results The various stages of image score proportion between the two groups had no significant difference(P＞0.05).The average score of reading image of the observation group was (1.52±0.33)points,which of the control group was (1.48±0.46)points,there was no difference between the two groups(t=0.857,P＞0.05).The CTDL,DLP and ED in the observation group were significantly lower than the control group[the observation group:CTDL(23.41±5.82),DLP(224.61±85.44),ED(3.01±1.12)mSv;the control group:CTDL(34.09±6.77),DLP(82.93±94.28),ED(5.33±2.01)mSv],and the differences were statistically significant(t=11.963,12.443,10.083,all P＜0.05)].Conclusion Prospective ECG gated sequence technology can effectively reduce the radiation dose of the patients under dual source CT coronary angiography,reduce probability of radiation damage,and the image quality is not changed obviously,which meets the needs of clinical diagnosis.

Objective To analyse CT signs of giant cell tumor of bone.Methods CT appearances of 42 cases of giant cell tumor of bone were reviewed.All patients were pathological proven.Results (1)Two kinds of bone destruction were seen in all ases:expansive cystic destruction and osteolytic destruction.The anterior was predominantly.(2)Most of our patients haven't bone septations in their tumors (95.2%).(3)Bone crests were usually seen in our study(63.2%).(4)Complete or incomplete sclerotic borders existed in 44.7% of all cases.(5)The inner bone soft tissues were heterogeneously in most of the patients.Fluid-fluid level can be seen in 5 cases (11.9%).(6)The outer-bone soft tissue masses were demonstrated in the majority cases with discontinuous bone shell.Conclusion CT may deepen our understanding and add imaging signs about giant cell tumor of bone;Which can enhance our diagnostic and differential diagnostic capability.

Objective To analyze CT manifestation of Schistosoma haematobium cystitis.Methods Retrospective analysis 32 patients,who were tested for Schistosoma haematobium cystitis using the urine filtration method.CT scan was performed for each patient with contrast enhancement.Results The vast majority of urinary tract schistomiasis lesions were in the urinary bladder.Calcification of the bladder wall was observed in all patients and mild enhancement in non calcified zone was found after intravenous contrast.Except for 5 patients of bladder cancer,the rest were no abnormality in size of bladder when bladder was filling or emptying.Ureteral wall annular calcification could also be identified in 25 patients.Twenty two patients were companied with ureteric hydronephrosis.Seminal vesicle calcification was seen in 4 patients among 11 male patients,while both uterine and ovarian in female and prostate in men had non calcification.Serious illness can be combined with bladder cancer.In 5 patients of patients with bladder cancer,bladder showed irregular soft tissue mass which was enhanced moderately after post-contrast scan,with vesical calcification in mass medially.Conclusion Bladder calcification is the most prominent CT feature of Schistosoma haematobium cystitis,which is useful in diagnosis the disease.