Objective To investigate the role of DWI in differentiating autoimmune pancreatitis ( AIP) from pancreatic cancer ( PC) , and in the therapeutic effect evaluation of AIP.Methods DWI data of 26 cases with AIP , 29 cases with PC and 30 cases with normal pancreas ( NP ) were analyzed retrospectively.The distribution type and signal feature of lesions in cases with AIP or PC were evaluated by Chi-squared test.ADC values were measured and compared among 3 groups by Kruskal-Wallis test.ADC values of AIP and PC were analyzed by using ROC curve to determine the optimal threshold and diagnostic efficiency.ADC values were compared in AIP ( n=15 ) before and after steroid therapy by paired t test.Results Diffuse lesions were detected in 21 cases with AIP and 3 cases with PC, while focal lesions in 5 cases with AIP and 26 cases with PC (χ2 =27.64, P<0.01).On DWI, most of AIP (n=19) and PC (n=24) showed hyper-intense signal, while a few of AIP (n=7) and PC (n =5) showed iso-intense signal (χ2 =0.75, P>0.05).The median ADC values of AIP, PC and NP were 1.15 ×10 -3,1.35 × 10 -3 ,1.59 ×10-3 mm2/s, respectively; and the difference was statistically significant ( H=45.60, P <0.01).ROC analysis yielded an optimal ADC cutoff value of 1.255 ×10 -3 mm2/s (80.8% sensitivity, 79.3%specificity and 0.871 area under curve for the diagnosis of AIP ).ADC values of AIP ( n=15) were markedly increased from the baseline (1.10 ±0.19) ×10 -3 to (1.57 ±0.12) ×10 -3 mm2/s after steroid therapy (t=-10.14, P<0.01).Conclusions DWI may be useful for diagnosing and evaluating the effect of steroid therapy in AIP.ADC values of AIP were significantly lower than those of pancreatic cancer and normal pancreas.After steroid therapy , ADC values were markedly increased in AIP.

Objective To investigate the diagnostic value of DWI on nasopharyngeal neoplasm recurrence and fibrotic lesions after radiotherapy.Methods A retrospective analysis of pathologically confirmed nasopharyngeal neoplasm was performed in 39 patients with recurrent patients ( recurrence group ) confirmed by biopsy or MRI follow-up and 51 patients with confirmed localized fibrosis (fibrosis group) after radiotherapy.All patients underwent DWI , non-enhanced and enhanced MR scan.DWI findings and ADC values of the lesions in two groups of patients were observed and measured , then compared by using independent samples t test.Diagnostic performance of routine MRI and DWI in the diagnosis of nasopharyngeal neoplasm recurrence after radiotherapy was calculated by using ROC analysis and the differences of both of them were analyzed by using Z test.Results DWI of 39 recurrent patients showed hyper-intensity signal and ADC map showed hypo-intensity signal appearance.Overall signal of DWI in 51 recurrent patients is lower than that in recurrent group , in which ADC maps of 36 cases showed iso-intensity or moderately hypo-intensity signal appearance and the remaining 15 cases showed moderate hyper-intensity signal appearance.The ADC values of recurrent group and fibrotic group were (0.753 ±0.127) × 10 -3 mm2/s, and ( 1.233 ± 0.310 ) ×10 -3 mm2/s, respectively.The difference was statistically significant ( t=-9.118, P<0.05).On the ROC curve, the sensitivity of ADC for the diagnosis of tumor recurrence was 87.18%(34/39), specificity 94.12%(48/51) and area under the ROC curve 0.968 with the ADC cutoff value of 0.887 ×10 -3 mm2/s.The sensitivity of routine MRI was 71.79% ( 28/39 ) , the specificity 74.51% ( 38/51 ) and the area under the ROC curve was 0.732 for the diagnosis of tumor recurrence.The difference of area under the curve between them was statistically significant ( Z=4.583, P<0.01).Conclusion DWI can help tumor detection and diagnosis of recurrent nasopharyngeal neoplasm and has a higher diagnostic performance compared with routine MRI.

Objective To explore the feasibility of prediction of subacute infarct lesion volumes by processing ADC maps based on ADC cut-off values in patients with acute stroke.Methods MRI was performed in 20 patients with clinically diagnosed acute infarct less than 6 h after stroke onset.The MRI included a DWI and conventional MRI.The follow-up MR examinations of all the patients were carried out within 4-7 days after admission.The brain tissue, which showed abnormal high intensity both in DWI at the baseline and FLAIR at the reexamination , was regarded as the area of the initial ischemia core.Graphic-penumbra was regarded as the difference between initial DWI and follow-up FLAIR.The ADC values of the ischemia core, graphic-penumbra and the contralateral normal brain tissue , the relative ADC (rADC) were measured.The rADC value of the graphic-penumbra was defined as the ADC cut-off values.GE medical system based on ADC cut-off values was also tested in these patients to obtain ADC maps.The lesion volumes, the abnormal area seen on the DWI , ADC maps and follow-up FLAIR, were also measured.rADC values in different areas were analyzed by paired Student t test.Relationship between baseline DWI , ADC map and follow-up FLAIR was analyzed using Spearman rank-order correlation test , and Kruskal-Wallis H test was used to compare the volumes among three groups.Results Absolute ADC and rADC values gradually increased from the core to the periphery of the ischemic lesion.The absolute ADC values statistically differed from those on the contralateral side for both ischemia core and graphic-penumbra.The rADC values were significantly decreased in the ischemia core ( 0.620 ±0.116 ) compared with the graphic-penumbra values (0.809 ±0.097;t =8.083,P <0.01).The lesion volume of follow-up FLAIR [16.3 (4.7, 29.0) cm3 ] correlated highly with both volume predicted with the ADC map [13.5 (4.8, 25.4) cm3] (r=0.967, P<0.01) and baseline DWI volume [11.0 (4.4,30.4) cm3] (r=0.950, P<0.01).There was no difference between the volume of DWI , ADC map and follow-up FLAIR(H=0.168, P>0.05).Conclusions Data shows the high feasibility of prediction of subacute infarct lesion volumes by processing ADC maps based on ADC cut-off values in patients with acute stroke , without intravenous contrast material, and it provides a new method for outcome prediction.

Objective To investigate the time course of cerebral infarction with diffusion kurtosis imaging-related parameters.Methods According to the time interval from symptom onset to MRI examination, 114 cases of cerebral infarction were divided into five groups:8 cases of hyperacute phase(less than 6 hours), 14 cases of acute(>6-24 h), 60 cases of early subacute(>24 h-7 d), 20 cases of late subacute(>7-14 d), and 12 cases of chronic phase ( >14 d-2 months).They underwent routine diffusion weighted imaging (DWI) and diffusion kurtosis imaging (DKI) scanning, and apparent diffusion coefficient ( ADC) and DKI-derived parameters were obtained from them.The derived diffusion parameters were compared among different phases in the patients , and the percent of changes in the infarcted regions were calculated.Paired t-test was used to compare the difference of each parameter between the infarcted region and contralateral normal region , and their correlation with time interval was tested using Pearson correlation analysis.Results Except for chronic phase , mean kurtosis ( MK) , axial kurtosis ( K∥) , radial kurtosis (K⊥)map showed uneven high signal in the infarcted regions , while mean diffusion(MD), axial diffusion(D∥), radial diffusion(D⊥) showed uniform low signal.MK values in the infarcted regions of hyperacute, acute, early subacute and late subacute phase (1.331 ±0.357,1.578 ±0.453,1.519 ±0.455, 1.403 ±0.275 ) increased significantly , compared with the contralateral normal mirror regions ( 0.850 ± 0.236,0.827 ±0.194,0.865 ±0.144,0.939 ±0.212) (t values were 5.242,6.907,12.416,5.629, respectively.P values were all less than 0.01 ).MK, K∥, K⊥ achieved a peak in the acute and early subacute phase , and showed more amplitude than the decrease of MD , D∥, D⊥.Then they gradually reduced, and tended to normalize.MK, MD, ADC had a significant correlation with the time onset of cerebral infarction ( r was 0.354, 0.747, 0.723, respectively, P values were all less than 0.05 ).Conclusion Diffusion kurtosis imaging can provide more diffusion information than conventional DWI , which can better reflect the microstructure changes in tissue.

Objective To discuss the feasibility and accuracy of dual-source CT ( DSCT) in the evaluation of aortic stenosis ( AS) with transthoracic echocardiography ( TTE) as reference.Methods A total of 53 patients who underwent both DSCT and TTE were prospectively evaluated.All of them were assessed by TTE for aortic stenosis.Maximum aortic valve area ( AVA) in systolic phase was measured with DSCT , and was compared to that index obtained from the continuity equation on TTE.The severity of AS was graded as mild , moderate , or severe according to the AVA.Linear regression analysis and Bland-Altman plots were used to compare the AVA measured by using CT and TTE.Agreement on semi-quantitative grades of AS severity between the two methods was tested by using Kappa statistics.Results The mean AVA using DSCT was (1.45 ±0.35 ) cm2 compared to the mean AVA of ( 1.33 ±0.36 ) cm2 using TTE, with a significant correlation between them (r=0.92,P<0.01).Bland-Altman analysis demonstrated good inter-modality consistency between DSCT and TTE.However , DSCT demonstrated a slight overestimation of the AVA compared to TTE.As identified by TTE, there were 53 patients with AS, 13 with mild AS, 21 with moderate AS , and 19 with severe AS.In 3 patients DSCT showed no AS , TTE detected mild AS.In 6 cases, TTE had graded the stenosis as moderate , but the stenosis degree was graded as mild using DSCT.Kappa analysis showed a good agreement between the two methods on semi -quantitative grades of aortic stenosis severity (Kappa=0.75,P<0.01).Conclusion AVA measurements using DSCT is feasible and reasonably accurate for those patients with moderate to severe aortic stenosis.

Objective To evaluate prognostic effects and complications of interventional embolization at different time points on patients with ruptured intracranial aneurysms of Hunt -Hess Ⅳ-Ⅴlevels.Methods Through a retrospective analysis from 2008.1 to 2012.12, we collected 162 from 200 patients who underwent interventional embolization due to ruptured intracranial aneurysms according to the criteria.Patients with serious neurological disorders , coma, and end-stage diseases were excluded.Brain CT scan was performed to identify the spontaneous subarachnoid hemorrhage of the patients , followed by CTA or digital subtraction angiography ( DSA) to ensure the accurate diagnosis of intracranial aneurysms.All of the patients at Hunt-HessⅣ-Ⅴlevels were treated with interventional embolization , and were divided into two study groups:early stage therapy group of 79 patients ( embolization at the time <72 hours after the onset) and late stage therapy group of 83 patients ( embolization at the time ≥72 hours after the onset ).Factors including pre-and post-interventional Glasgow coma score ( GCS ) and Glasgow outcome score , ( GOS) as well as barthel index ( BI ) were statistically compared between the study groups.T-test was performed to compare the data between the two study groups.Chi-square test was taken to evaluate the enumeration data.And the correlation of therapeutic time and prognosis of patients was demonstrated by binary regression analysis.Results In the patients with ruptured intracranial aneurysms at Hunt-Hess Ⅳ-Ⅴlevels, early stage intervention (63.5 ±13.5) resulted in significantly better BI after three months , and demonstrated better recovery in comparison to the late stage intervention group (34.8 ±12.7) ( t=6.127, P<0.05).But no statistical significance of post-operative GCS (6.6 ±1.6 in early therapy group;6.1 ± 1.4 in late therapy group ) and discharging GOS ( 3.0 ±0.7 in early therapy group; 2.9 ±0.7 in late therapy group) was found between the two groups (t=1.822, 0.631 respectively; P>0.05).The early therapy group also presented a significant decrease of complications , such as hydrocephalus (χ2 =6.369, P<0.05 ) and venous thrombosis (χ2 =5.158, P <0.05 ), compared to the late therapy group.Furthermore, Statistical analysis revealed that therapeutic time closely correlated with the prognosis of patients with ruptured intracranial aneurysms at Hunt-Hess Ⅳ-Ⅴ levels ( P =0.009, OR =3.897).Conclusion The early stage therapy can improve the prognosis and decrease incidence of complications , which should benefit the efficient management of the patients with interventional embolization of ruptured intracranial aneurysms.

Objective To evaluate the safety and effectiveness of treating the endovascular stents placement for spontaneous isolated dissection of splanchnic artery ( SIDSA).Methods Sixteen consecutive patients with diagnosis of SIDSA through CTA and DSA were retrospectively analyzed .All patients had acute persistent abdominal pain and treated by endovascular stents placement.The serious complications and symptoms improvement were reviewed after the operation.The symptoms recurrence and repeated color doppler ultrasonography and CTA were also reviewed in the follow up.Results Twelve superior mesenteric artery ( SMA) dissection and four celiac artery ( CA) dissection were diagnosed among sixteen patients.The dissection length was 1.07 to 11.87 cm and the median length was 3.93 cm.The distance from the original dissection to the orifice of superior mesenteric artery or celiac artery was 0.50 to 6.44 cm and the median was 1.98 cm.Eight stent-grafts and 3 bare stents were successfully implanted in 11 patients.One case with celiac dissection was failed to treat because of the severe compression of true lumen and the guide wire cann′t cannulate to the distal true lumen.Four patients with superior mesenteric artery dissection gave up interventional therapy , Among these 4 patients , 2 patients had small tear site and small false lumen , 1 patient had extremely long dissection , and one case had blood supply of target organs from both true and false lumen.No severe complications such as hemorrhage , intestinal necrosis , hepatic failure and splenic necrosis occurred during the eleven successful endovascular interventions.The abdominal pain in 10 cases was disappeared or significantly relieved , 1 case with superior mesenteric vein thrombosis and severe intestinal ischemia before intervention underwent intestinal resection for necrosis.The follow up period was 1 to 74 months in eleven successful cases , and the median follow-up period was 16 months.One patient with SMA dissection after endovascular treatment was died of sudden stroke three months later .Others had satisfactory outcome and the repeated color doppler ultrasonography and CTA were normal .Conclusions Endovascular stents placement is a safe and effective therapy for symptomatic spontaneous isolated dissection of splanchnic artery.

Objective To prepare a new thrombus model by fluid model method , which is suitable for evaluation of mechanical thrombectomy devices for acute stroke.Methods The fluid model adopted the Chandler loop theory , while the static model adopted conventional method.Mechanical properties of thrombi prepared by fluid model and static model were measured by manual elongation test ( 15 samples in each group) and catheter injection test (15 samples in each group ).Histological structure was compared among the above thrombus models ( 5 samples in each group ) and specimens of five patients with stroke by hematoxylin-eosin staining method.Then, thrombi in fluid model were utilized to establish embolization of vessels in swine model ( two pigs ) for evaluation of radiopacity.Independent-Sample test was performed to compare the maximum tensile length of two methods , and Fisher′s exact test was used to compare the rate of thrombus fragmentation after catheter injection test.Results The maximum tensile length of two models were (4.28 ±0.23) and (3.16 ±0.13) cm, respectively, and the difference was statistically significant (t=16.38, P<0.01);After catheter injection, the fracture rates of thrombus were 13% (2/15) and 60%(9/15), which were also statistically significant (P<0.05).As to histological structure, thrombi prepared by fluid model showed mixed thrombus structure , which similar to thrombi of stroke patients , But thrombi prepared by static model were replete with erythrocytes under the microscope .A total of eight vessels ( lingual arteries and superficial cervical arteries ) in two swines were successfully occlusive ( TIMI 0 or 1 ) , and sufficient radiopacity of each injected thrombus was observed.Conclusions The thrombi prepared by fluid model not only have good mechanical stability and sufficient radiopacity , but their histological structure is similar to thromboemboli retrieved from cerebral arteries of patients with acute stroke.

Objective To explore imaging features of Zinner syndrome.Methods Eight male patients with clinically diagnosed Zinner syndrome performed abdominal and pelvic CT and /or MRI scan.The radiological data was studied retrospectively.Results Eight cases showed seminal vesicle cyst with ipsilateral renal agenesis on CT and/or MR imaging ( left side, n =5; right side, n =3).The maximal diameter of seminal vesicle cysts varied from 4.2 to 7.0 cm, and appeared as oval cystic lesion with irregular contour or tube-like dilatation , which appeared low density on CT image and hypo-or hyperintensity on T 1 WI and hyperintensity on T 2 WI.Bladder compression was found in 6 cases.Fuild-fuild level in the cysts was seen in 2 cases.Remnants of ureter structure were seen in only 1 case.There was no other accompanying abnormality of urinary system.Conclusions Zinner syndrome presents with characteristic imaging features , and the key issue is differential diagnosis of seminal vesicle cysts.

Objective To investigate the value of DWI before treatment on predicting sensitivity of concurrent chemoradiation in nasopharyngeal carcinoma.Methods Seventy patients with nasopharyngeal carcinoma proved by nasopharyngoscope and biopsy pathology conducted DWI before concurrent chemoradiation and reexamined on receiving dose of 50 Gy.The mean, maximum and minimum ADC value of tumor were measured on DWI and maximum area of tumor before and during treatment ( on dose of 50 Gy) was delineated to calculate the tumor regression rate ( RS0-50 ).The patients were classified into three groups according to the RS0-50 as sensitive, moderate, and resistant therapeutic effect.Patients were classified into different groups according to the pathologic type and clinical stage respectively .Spearman correlation analysis was used between RS 0-50 and ADC values of all tumors , different pathologic types and clinical stages , respectively.ROC was used to evaluate the cutoff and value of ADC which had highest correlation to RS0-50 on predicting therapeutic effect.Results DWI of 3 patients were excluded due to obvious swallow artifact which influenced the measurement , and finally 67 patients were included in this study, with pathological type of nonkeratinized differentiated undifferentiated carcinoma in 49 cases, nonkeratinized undifferentiated carcinoma in 18 cases, clinical T1 stage in 7 cases, T2 in 14 cases, T3 in 17 cases and T4 in 29 cases.During treatment , there were 13 cases with sensitive therapeutic effect , 42 cases with moderate therapeutic effect and 12 cases with resistant therapeutic effect.RS0-50 [ ( 65.6 ± 3.1) %] showed mildly and moderately negative correlation to mean ADC [(1.06 ±0.19) ×10 -3 mm2/s] and maximum ADC [(1.29 ±0.33) ×10 -3 mm2/s] respectively ( r =-0.276, P =0.024 and r =-0.434, P=0.001, respectively).ROC showed when setting threshold at maximum ADC value of lower than 1.06 ×10 -3 mm2/s for predicting sensitive therapeutic effect , the specificity , sensitivity , and accuracy was 69.2%(9/13), 88.9%(48/54) and 85.1% (57/67), respectively, and when setting threshold at maximum ADC value of higher than and equal to 1.30 ×10 -3 mm2/s for predicting resistant therapeutic effect, the specificity, sensitivity, and accuracy was 75.0% (9/12), 65.5% (36/55) and 67.2%(45/67), respectively.Conclusion Pretreatment maximum ADC value were able to predict the tumor regression rate and sensitivity of concurrent chemoradiation in nasopharyngeal carcinoma .