Objective To investigate the routes and MR imaging manifestations of meningeal involvement by nasopharyngeal carcinoma (NPC) with pathological correlation. Methods Twenty five NPC patients with involvement of meninges were included into the study. All patients underwent both unenhanced and Gd DTPA enhanced MR imaging examinations. Surgical and pathological findings were correlated with MR imaging manifestations in 9 patients. Positive cytology was found in only 1 of the 25 patients. Results There were three main routes for meningeal involvement in NPC patients: (1).through the natural bony channels (foramens) of the skull base; (2).through direct bony erosion of the skull base; and (3).Through hematogenous spread. Dura mater was very frequently involved, being seen in 24 patients; pia mater was involved in only one patient. Irregular, patchy thickening in the form of “necklace”, nodules, or mass with obvious enhancement was the major MR feature of meningeal involvement by NPC. In one patient with choroid plexus involvement, dilatation of the lateral ventricles, subependymal nodules with patchy thickening were observed. Conclusion MR imaging with Gd DTPA enhancement was very useful to demonstrate the presence, location and extent of meningeal involvement in NPC patients.

Objective To study the characteristics of susceptibility weighted imaging (SWI) and it's role in glioma classfication. Methods 45 glioma patients with pathologically confirmion, underwent preopera-tive plain MRI, enhanced MRI and SWI examination. By using double blind method, the score of T1 WI, T2WI, enhanced T1 WI, SWI and enhanced SWI were acquired to display enhancing tumor, peritumoral edema, tumor hemorrhage and tumor vein. The tumor volume of low signal areas was measured by using measurement software to acquire the bleeding of tumor. Results In 26 cases of high grade gliomas,18 patients with intratu-moral, multiple patchy low signal cords in varying degrees, which were proved by pathology as tumor hemorrhage and tumor blood vessels; in 19 case of low grade gliomas, 10 cases occured a few spots, linear low signal in tumor, which were proved by pathology as tumor hemorrhage; the bleeding of high grade gliomas was higher than that of the low level group ( P < 0.05 ). SWI was superior to T, WI, T2 WI on displaying tumor hemorrhage and tumor vein(P<0. 05). Conclusion Different grades of glioma show obvious different display on SWI, and SWI probably be helpful for evaluation of glioma grading preoperatively.

Objective To study the characteristics of diffusion tensor imaging (DTI) in brain tumor and it's diagnosis and differential diagnosis value.Methods Thirty-nine patients with brain tumors proven by pathologically (10 meningioma,17 glioma,12 metastatic tumors) were enrolled,by using Philips Achieva 1.5 T MRI,conventional MRI and DTI were underwent on them,fractional anisotropy (FA) maps,apparent diffusion coefficient (ADC) maps and three dimensional white matter fiber bundle map were reconstructed in the workstation.The core substance of the tumor area and the contralateral mirror area were selected as the region of interest,and FA and ADC values of them were measured,and t test was performed.Results The FA values of meningioma,metastases tumors and gliomas were 0.36 ± 0.08,0.28 ± 0.03,0.18 ± 0.06,respectively,and the differences among them were significant( P ＜ 0.05).The ADC values of meningioma,metastases tumors and gliomas were 1.72 ± 0.10,1.52 ± 0.22,1.34 ± 0.14,respectively,and the differences among them were significant( P ＜ 0.05).Conclusion DTI has high clinical value in identification of meningiomas,metastatic tumors and glioma.

Objective To evaluate the usefulness of diffusion-weighted magnetic resonance imaging (DWI) and apparent diffusion coefficients (ADC) in differentiating tumor, edema, and normal brain tissue, and in classification of cerebral gliomas. Methods Using Philips Achieva 1.5T super conduct MR scanner, 46 patients with gliomas underwent conventional MR imaging and DWI. The ADC of regions of interest ( ROI ) were measured with two different b values, 0s/mm2 and 1000s/mm2. ROIs were manually placed over areas of tumor,edema, and normal brain tissue. Results The signals of DWI and ADC map in tumor tissue were respectively higher and lower than those in normal brain tissue. The ADC values in tumor were 1.68 ± 0.18,1.65 ± 0.20,1.29 ±0.16,1.21 ±0.21 for grade Ⅰ、Ⅱ、Ⅲ、Ⅳ gliomas, respectively; the corresponding figures in edema were 1.74 ±0.22,1.72 ±0.19,1.35 ±0.20,1.28 ±0.19, respective. The ADC values in tumor were not significantly different from the values in edema (P ＞0.05); however, both values were significantly different from those in normal brain ( P ＜0.05 ). The ADC value of low grade ( grade1-2 ) gliomas was significantly higher than that of high grade (grade3-4) glioma (P＜0.05). Conclusion ADC values can aid in distinguishing tumors from normal tissues, but can not distinguish tumors from adjacent edema. Individually, ADC values overlapped considerahly. ADC value is associated with cellularity of gliomas. DWI can help characterizing the malignancy of gliomas.

Objective To observe CT features of struma ovarii (SO) in comparison of pathologic findings. Methods CT features of 9 patients with pathologically confirmed SO were analyzed retrospectively and compared with pathological findings. Results All tumors were unilateral and had smooth margins, 3 were cystic and 6 were cystic-solid lesions, 5 were high attenuation lesions in the cyst portion of the mass on contrast CT. The cyst wall moderately (n=3) or markedly (n=5) enhanced after administration of contrast medium. Scattered, stripe-like or ring-like calcifications were found in 6 patients. On pathology, most of cystic portions were filled with high proteinaceous gelatinous fluid of eosinophiclic colloid, and the solid portion of tumors consisted of the thyroid tissue and stoma containing abundant blood vessels and fibrous tissue. Conclusion SO appears as a smooth marginated multicystic mass with calcification, high attenuation lesionin plain CT, and marked solid part enhancement on contrast CT.

Objective To assess influence factors of imaging quality with 64-slice spiral CT angiography (CTA) of renal artery. Methods A total of 305 hypertension patients underwent CTA of renal artery, and 108 of them were examined with DSA. The imaging quality was classified as Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅴ, and the degree of stenosis wass classified as <50%, 50%-74%, 75%-99% and occlusion. The sensitivity and specificity of CTA of renal artery was analyzed taking DSA as the standard. Results The influence factors of CTA of renal artery included the delayed time set, rotation time, the units dose of contrast medium and the speed of injection, breath-holding, the patients age and vascular calcification. The sensitivity and specificity of CTA of arterial stenosis <50%, 50%-74%, 75%-99%, occlusion was 76.30% and 76.80%, 89.70% and 90.40%, 96.30% and 97.10%, 100% and 100%, respectively. Conclusion The influence factors of CTA of renal artery are the delayed time set, rotation time, the units dose of contrast medium and the speed of injection, breath-holding, the patients age and vascular calcification. CTA of renal artery can meet the clinical requirements in assessing the renal arterial stenosis.

ObjectiveTo analyze the characteristics of magnetic resonance diffusion tensor imaging(DTI)and diffusion tensor tractography (DTIT) in patients with cerebral infarction, and explore the diagnosis values and prognosis of diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) in patients with cerebral infarction in different stages. Methods58 patients with cerebral infarction in different stages and 25 healthy volunteers were examined by magnetic resonance imaging(MRI), including conventional T1 and T2 weighted imaging, DWI and DTI. Fractional anisotropy (FA) images were reconstructed. The values of FA and apparent diffusion coefficient (ADC) were measured in the infarcted regions, corresponding contralateral normal regions and corresponding normal regions in normal control group. Results①DWI and DTI showed size of infarction focus was more accurate and clearer than that of conventional MRI; ②The FA and ADC values of the infarcted regions during superacute stage, acute stage, subacute stage and chronic stage were (0.24±0.02, 0.31 ±0.11), (0.20±0.02, 0.32±0.12), (0.18±0.02, 0.34±0.11) and (0.16±0.02, 0.37±0.13), respectively, lower than those in the contralateral corresponding regions which were (0.40±0.03, 0.70±0.21), (0.37±0.03, 0.71±0.21), (0.39±0.03, 0.72±0.22) and (0.40:±0.03, 0.72±0.23), respectively. The differences were statistically significant (P＜0.05). The FA and ADC values had no significant differences between the uninjured sides in patients with cerebral infarction and the corresponding regions in the normal control group (P＞0.05); ③The FA and ADC values in brain tissues changed regularly with the time of infarction after cerebral infarction. The FA values in the affected sides had no consistent changes as compared with the contralateral sides in the superacute stage. They increased or decreased slightly, then (during acute stage, subacute stage and chronic stage) decreased irreversibly. The ADC values in the affected sides changed with time regularly, they decreased significantly, gradually returned to normal, and then increased again. Conclusion DTI and DTT examination contribute to the diagnosis of cerebral infarction. The combination of the FA and ADC values may more accurately conduct clinical staging and evaluate the time of the occurrence of cerebral infarction.

Objective To study the value of MR diffusion weighted imaging(DWI)and apparent diffusion coefficient(ADC)in differentiating benign and malignant lesions of prostate.Methods Twenty-two patients with prostate cancer and 17 patients with benign prostatic hyperplasia confirmed by pathology or biopsy,and 20 healthy volunteers were underwent prostate plain MRI,DWI and enhanced MRI,and measuring the value of ADC in the regions of interest in the workstation,and the ADC values of prostate cancer,benign prostatic hyperplasia,normal prostate were analyzed statistically.Results The ADC of prostate cancer,benign prostatic hyperplasia,normal prostate in central gland and peripheral zone were 1.08 ±0.23,1.43 ±0.27,1.51 ±0.26 and 1.26 ±0.47,1.72 ±0.40,1.75 ± 0.28,respectively,the ADC of prostate cancer was significantly lower than that of benign prostatic hyperplasia and normal prostate,and there was significant difference(P＜ 0.05),but there was no significant difference between benign prostatic hyperplasia and normal prostate(P ＞0.05).Looking the ADC was 1.30 and 1.60 in central gland and peripheral zone as the threshold to distinguish benign and malignant lesions of prostate,had high sensitivity and specificity.Conclusion The application of DWI combined with ADC,has improved the capability of diagnosis and differential diagnosis in benign and malignant lesions of prostate greatly.

Objective To explore the value of fascial tail sign at MR images in the detection of nodular fasciitis (NF). Methods A retrospective analysis of MR images was performed in 19 patients with pathologically proven NF of the soft tissue and 53 patients with a variety of other fibrous-predominant tumors. MR manifestations of all cases were reviewed by two experienced musculoskeletal radiologists using a single blind method. The presence of fascial tail on MR images were evaluated. ROC was used to assess the value of fascial tail sign in the detection of NF. Sensitivity, specificity, Youden index and area under ROC curve were calculated. The association between the presence of fascial tail sign on MRI and pathological classification of NF was analyzed by Pearson chi-square test for independence . Results Fascial tail was present in 17 cases (89.5%) of the study group and in 6 cases (11.3%) of the control group, respectively, yielding a sensitivity of 89.5%, a specificity of 88.7%, a Youden index of 0.782 and an area under ROC curve of 0.891. The fascial tail sign was significantly associated with NF (c2=39.294,P<0.05,r=0.594). Conclusions Fascial tail sign at MRI is a moderately specific and sensitive for the diagnosis of NF relative to fibrous-predominant tumors. It can be used in differentiate between NF and aggressive soft tissue tumors.

Objective To explore the optimal body size index for the calculation of iodine contrast agent dose required for multiphase liver enhanced CT scans based on the total body weight (TBW),lean body weight (LBW)and body surface area (BSA).Methods Two hundred and twenty enrolled patients were randomly divided into three groups,TBW-group (n＝75),LBW-group (n＝72)and BSA-group (n＝73),and administrated iodine doses were 600 mg I/TBW(kg),780 mg I/LBW(kg)and 22 g I/BSA(m2 ),respectively.All patients had taken upper abdominal plain scans and triple-phase enhanced CT scans.The enhanced values (ΔHU)of the aorta at hepatic arterial phase (HAP),the portal vein and liver parenchyma at portal venous phase (PVP)were compared.The correlation coefficients of adjusted maximal hepatic enhancement(aMHE)with TBW,LBW and BSA in three groups were evaluated,respectively.Results There were no statistical differences in the ΔHU values of the aorta at HAP and the portal vein and liver parenchyma at PVP in the three groups respectively.The smallest variances of the aorta at HAP,the portal vein and liver parenchyma at PVP were found in the LBW group. The aMHE showed mildly positive correlation with TBW (r＝0.230)with a P value of 0.047,but it was consistent with LBW (r＝0.158)and BSA (r＝－0.1 54)with corresponding P values of 0.1 85 and 0.1 9 2 ,respectively.Conclusion Compared with TBW and BSA,iodine contrast agent dose calculated based on the patient’s LBW can improve the patient-to-patient uniformities on aorta,portal vein and liver enhancement during the liver multiphase enhanced CT scans.The LBW is the best body index for the calculation of iodine dose on liver enhanced CT scans.