Objective To explore the performance of meningiomas in MRI dynamic enhancement and DWI sequence,and to improve the accuracy of differential diagnosis of benign and malignant meningiomas.Methods Meningioma MRI data,which were pathology proved by the Guilin medical college affiliated hospital at different levels(Ⅰ,Ⅱ and Ⅲ),were retrospectively analyzed.The enhancement of meningiomas at all levels and the extent of edema were summarized,at the meantime the dynamic enhancement perfusion parameters and ADC values of meningioma MRI meningioma were contrastively analyzed.Results There were 30 cases of meningioma located in the brain falcus,27 cases of meningioma located in the sagittal sinus,10 cases of meningioma located in the cerebellopontine angle and 6 cases of meningioma located in other parts.The difference of ADC value between grade Ⅰ meningiomas and grade Ⅲ meningiomas was statistically significant different[(1.253±0.123)×10-3 mm2/s vs.(0.891±0.103)×10-3 mm2/s,P<0.05].The relative blood flow(rCBF)and relative blood volume(rCBV)of grade Ⅰ meningiomas were significantly lower than those of grade Ⅲ meningiomas(P<0.05).Conclusion MRI dynamic enhancement combined with DWI can accurately identify grade Ⅰ meningiomas and grade Ⅲ meningiomas,and it is necessary that the assessment of its classification should be appropriately considered to the higher level for patients who do not have a characteristic manifestation of meningioma in the preoperative.

Objective To investigate the optimal b value of diffusion-weighted imaging (DWI)in predicting the grade of cerebral gliomas.Methods 38 patients with pathologically-proved brain gliomas (24 high-grade gliomas and 14 low-grade ones)were studied retrospectively.All patients received conventional MRI and DWI examination with three different b values (1 000 s/mm2 ,2 000 s/mm2 and 3 000 s /mm2 ).The signal features of the tumor on DWI with three different b values were evaluated and compared.The minimum ADC values of the tumors were calculated and compared between each other.Through drawing the ROC curve of different b values, the best diagnostic threshold was found.The sensitivity and specificity in predicting the grade of brain gliomas were assessed using Chi-square test.Results On DWI with b value of 3 000 s/mm2 ,91.6% (22/24)of high-grade tumors showed hyper-intensity, while 85.7%(12/14)of low-grade tumors presented hypo-intensity signals.Regarding hyper-intensity signals as diagnostic criterion for high-grade tumors,the sensitivity and specificity were 91.6% and 100% respectively.When the b value was similar,the minimum ADC value of high-grade glioma was significantly lower than that of low-grade glioma,and statistically significant differences in differentiating high-grade glioma from low-grade glioma existed among three b values (P <0.05).When the ADC 3 000 value<0.74×10 -3 mm2/s was regarded as a standard for the identification of high-grade and low-grade glioma,the sensitivity and specificity were 100% and 87.3%respectively.Conclusion DWI with high b value is more useful than standard moderate b value in preoperative grading the gliomas.When DWI with b value of 3 000 s/mm2 is used,the minimum ADC value will provide quantitative indicators in preoperatively precisely predicting grading glioma.

Objective To evaluate the clinical value of CT perfusion (CTP) imaging for providing quantitative information about angiogenesis in patients with lung carcinoma and investigate the correlation of CTP enhancement parameters and histological microvessel density (MVD) with lymphatic involvement in peripheral lung carcinoma. MethodsFifty-three patients with pathology-proved peripheral lung carcinoma underwent CT perfusion scan before operation. The enhancement parameters of CTP were calculated based on the time-density curves (TDC) of fist pass phase. All cases were classified into two groups according to pathologic results: tumor with and without lymph node involvement. Two-sample t test was used for the statistics. The ROC curve was used to assess the efficiency of the enhancement parameters of CT perfusion and MVD for predicting lymphatic involvement.Results Tumors with lymph node involvement had significantly higher value of MVD than those without lymph node involvement (64.69±16.34 and 42.67± 16.78, respectively,t=4.84,P<0.01). Tumors with lymph node involvement had significantly higher value of CTP enhancement parameters (PH, M/A, PV) than those without lymph node involvement [PH= (41.79±15.50) and (29.99±10.91) HU,M/A =0.24±0.09 and 0.15±0.06, PV=(2.14±1.09) and (1.27±0.53) ml·min~(-1)·ml~(-1), t=3.21,3.95, 3.66, P<0.01, respectively]. The CTP enhancement parameters (PH, M/A, PV) of lung cancer correlated positively with the MVD, the highest correlation coefficient was between the PV and MVD (r=0.716, P<0.01). MVD and PV had higher values for predicting lymph node involvement in ROC curve analysis.The sensitivity, specificity and accuracy for predicting lymph node involvement were 80.8%, 81.5% and 81.1% or 84.6% ,85.2% and 84.9% respectively if MVD>52/0.74 mm~2 or PV>1.52 ml·min~(-1)·ml~(-1). ConclusionThe CT perfusion PV and histological MVD have good correlation with lymph node involvement in peripheral lung carcinoma and are important predicting parameters before operation.

Objective To probe the value of both liver volume(LV)measurement and Gd-EOB-DTPA enhanced MRI to evaluate hepatic reserve function in order to obtain a better assessment method.Methods Clinical and imaging data of 42 patients with hepatic focal lesions were analyzed retrospectively.Gd-EOB-DTPA enhanced MRI scan,Child-Pugh scoring and ICG clearance tests were performed in all patients,and the liver relative enhancement (RE)and LV were used to assess the hepatic reserve function.The differences of LV, LV/standard liver volume (SLV)and RE between the Child-Pugh class A and B were compared using independent student's t-test. Spearman correlation analysis was applied to analyze the relationship of indocyanine green retention rate at 1 5 minutes (ICG-R1 5) with the LV,LV/SLV,RE,RE×LV and RE×LV/SLV.Results There was no significant difference in LV between two groups(P>0.05), whereas the RE had significant difference(P=0.039).There were no significant correlations between ICG-R15 and LV,LV/SLV(P>0.05). ICG-R1 5 was negatively correlated with RE,RE×LV and RE×LV/SLV,and RE×LV/SLV showed significant correlation with ICG-R15 (r=-0.524,P=0.000).Conclusion Gd-EOB-DTPA enhanced MRI can assess the status of hepatic reserve function, while the combination of RE with LV is a more effective method.

Objective To explore the CT and MRI characteristics of hepatic epithelioid angiomyolipomas (H EA)in order to improve recognition and diagnostic accuracy of the disease.Methods The CT and MR imaging data of 8 patients with HEA proved by pathology were analyzed retrospectively.Among these patients,4 cases underwent plain and enhanced CT scans,2 plain and enhanced MRI scans and 2 both CT and MRI scans.Results In the 8 cases,7 were female.All lesions were solitary and well-defined,with maximum diameters ranging from 42 mm to 68 mm.6 leions on plain CT displayed slightly low density,of which 1 showed fat density and other 2 showed patchy cystic areas.MRI showed 4 masses with slight hypointensity on T1 WI,slight hyperintensity or hyperintensity on T2 WI,of which one demonstrated decreased signal on out-phase of T1 WI.On enhanced MR images,7 masses were significantly inhomogeneous in arterial phase,5 showed "fast wash-in and slow wash-out",2 "fast wash-in and wash-out"and 1 "slow wash-in and wash-out".6 showed"central vascular sign"in arterial phase and 2 displayed incomplete pseudocapsule in the portal venous and delayed phases.Conclusion Inhomogeneous enhancement in arterial phase,central vascular sign,fast wash-in and slow wash-out enhancement and no pseudocapsule are imaging features of HEA,which can help to improve the diagnostic accuracy.Its diagnosis still depends on histopathology and immunohistochemistry.

Objective To investigate the CT features of pulmonary mucosa-associated lymphoid tissue (MALT)lymphoma. Methods The data of 20 cases with pathologically confirmed pulmonary MALT lymphoma were collected.All cases underwent CT plain and enhanced scan,and the CT features were analyzed retrospectively.Results Among the 20 cases,15 cases showed multiple consolidations,accompanied by mass and small nodules,1 case had solitary consolidation with multiple micronodules,2 cases had solitary consolidation,2 cases had diffuse micronodules.The sign of dilated air bronchograms was found in 10 cases with pulmonary consolidation lesions, reaching the margin of lesion.All lesions and masses were mildly and moderately homogenous enhanced.Pulmonary thin-wall cystic cavity was seen in 7 cases of diseased tissue and surrounding lung tissue.Conclusion CT manifestation of pulmonary MALT lymphoma mainly shows multiple lung consolidation,which includes the signs of consolidation with dilated air bronchograms,homogenous enhancement, and accompanying with signs such as mass,micronodules and pulmonary thin-wall cystic cavity.

Objective To explore the factors influencing the image quality of thyroid CT and the application value of optimization schemes in reducing streak artifacts in thyroid CT examinations.Methods A retrospective review of the data of 141 patients who underwent thyroid enhanced CT examinations was conducted to analyze the factors affecting image quality.After determining the influencing factors,a self-controlled study was conducted on 48 patients who underwent thyroid CT examinations to analyze the feasibility of the optimization scheme.Results The patients'body mass index(BMI),neck circumference,pharynx-jaw angle,and pharynx-jaw angle-to-neck circumference ratio showed statistically significant differences in their impact on image quality(P<0.05).Compared to the conventional scheme,the optimization scheme showed significantly higher subjective and objective image evaluations.The optimization scheme also significantly improved the diagnostic performance of the images,with statistically significant differences(P<0.05).There was no statistically significant difference in radiation dose between the two positions(P>0.05).Conclusion The optimization scheme can effectively reduce streak artifacts in thyroid CT examinations.