PurposeIt is important to keep the consistency of CT perfusion imaging (CTP) measurement in the evaluation of intracranial disorders. The purpose of this paper is to probe into the consistency of basal ganglia hemodynamic characteristics in normal rabbits with CTP measurement in the mode of volume helical shuttle (VHS).Materials and Methods Brain CTP scans of 10 healthy rabbits were carried out in the VHS mode. The images derived from CTP were separately analyzed by two radiologists (A and B) with different experiences. ROIs were placed in the bilateral basal ganglia of the subjects and parameters such as cerebral blood volume (CBV), cerebral blood flow (CBF) and mean transit time (MTT) were measured three times in each rabbit. Thirty days later, radiologist A analyzed the CTP images again with the same method. Differences of parameters in bilateral basal ganglia measured by different radiologists at different periods were compared respectively and consistency of the measurements was further assessed.Results There was no significant difference among the three measurements of CBV, CBF and MTT in bilateral basal ganglia (F=0.162, 0.050 and 0.488,P>0.05). TheICC of CBV, CBF and MTT measured by the two radiologists for the first time were 0.84, 0.81 and 0.79; while theICC of CBV, CBF and MTT measured by radiologist A twice were 0.80, 0.89 and 0.84, which showed that the results had good consistency measured by different radiologists at different times.Conclusion With the same post-processing software, the consistency of CTP of basal ganglia in the VHS mode is satisfactory in healthy rabbits, which suggests this technique may be a suitable means in the evaluation of basal ganglia hemodynamics in animal models.

Objective To observe the diffusion characteristics and pathology changes with DTI in rabbit models with mild cerebral contusion and laceration (CCL). Methods Thirty rabbits were randomly selected and made into models of mild CCL by free fall, while other 10 rabbits were cut only in the skull as control. T2WI and DTI were performed 1, 3, 6, 12, 24, 48 and 72 h after the operation. DTI value of average diffusion coefficient (DCavg) and fractional anisotropy (FA) of mild CCL and its peripheral area were measured and compared. Histological examination was also performed. Results One hour after operation, CCL area showed high signal on T2WI, and no abnormal signal was found in the peripheral area, but both had abnormal color on DTI map. T2WI signal intensity in peripheral area of 22 rabbits (73.33%) increased gradually and had much abnormal color on T2WT map after 3 h. There was significant difference of FA and DCavg between CCL and the mirror region, the peripheral area and the mirror region (P<0.05). The value of FA decreased slightly since 12 h. More prominent tissue necrosis, edema and hemorrhage were found in CCL area than in the peripheral area with pathology examination. No abnormal manifestations of the brain were detected with both pathology and MR examination in the control rabbits. Conclusion DTI is sensitive for detecting mild CCL and can show it directly on color map, and thus may be used as a routine examination in the evaluation of mild CCL.

Objective To investigate the lowest concentration of iodine contast medium which can ensure CT pulmonary angiography (CTPA) imaging quality at tube voltage of 80 kVp.Methods Ten New Zealand rabbits underwent CTPA four times every three days with the iodine concentrations of contrast medium at each time were 350,300,270 and 250 mg I/mL respectively.The attenuation values of trunk pulmonary artery and air around the body on the same level,as well as right and left pulmonary arteries,and the pulmonary artery branches were compared among different groups.Meanwhile,image noise (N),contrasvto-noise ratio (CNR) and signal-to-noise ratio (SNR) were calculated.All those data were analyzed with One way classification ANOVA test.When multiple samples compared,Dunnett-t test was employed.The pulmonary arteries were divided into large and small arteries and assessed by multiple sample Kruskal-Wallis H test and analyzed with LSD-t test when multiple samples compared.When the attenuation of trunk pulmonary artery of different viewers or the different times of the same viewer compared,paired t test was employed.Wilcoxon signed rank testing was employed for comparing the scores of pulmonary arteries among different groups.Results All the images of CTPA could demonstrate sixthorder branches of pulmonary artery.The attenuation of pulmonary arteries of the 300-group was the highest,however no statistical difference was found between 270 and 300-group [major pulmonary arteries:(687.17±167.83) HU,(848.68±185.03) HU,t=-161.52,P =0.097].The CNR (6.3±1.30) and SNR (10.9±2.01) of the 270-group were the highest (t=-45.99,P=0.008;t=3.73,P=0.088),and N (62.84±6.05) was the lowest (t=-11.09,P=0.016).No statistical difference was found between 270-group and other 3 groups.And for the subjective scores of large arteries,no statistical differences (from 350-group to 250 group,3.91±0.35,3.90±0.38,3.90±0.42 and 3.86±0.42,H=6.588,P=0.086) were found.The scores of small arteries of 270-group were lower than those of 350 and 300 group,but the image quality of 270-group (3.34±0.51) met the diagnostic requirements.Conclusion When the tube voltage being 80 kVp,the contrast medium of 270 mg I/mL is more suitable for rabbits' CTPA.Thus,the iodine dose per unit can decrease effectively.

Objective To describe MRI findings of 12 cases of non hemorrhagic contusion of corpus callosum. Methods The MR images of 12 patients were reviewed retrospectively. 11 cases were victims of vehicle accident and 1 patient was injured by falling. All patients were examined with precontrast CT and MR imaging within 3 days (8 cases) and 6 to 30 days (4 case). Results The lesions were located at splenium (3 cases) and mainly at body (9 cases). There was no abnormal signs of corpus callosum on CT images. MR study in all 12 cases demonstrated isointense or slight hypointense signal compared with gray matter on T 1WI and obvious hyperintense signal lesions on T 2WI on corpus callosum. There was no hemorrhagic signal or density on MR and CT images at corpus callosum. These contusion lesions were demonstrated nicely on SE or FSE T 2WI images. On FLAIR sequence, these lesions were revealed more clearly for the signal of CSF was suppressed. MR follow up examination in one case four months later, the contusion lesion became malacia with the signal similar to that of CSF. Several other multiple contusion and hemorrhage lesions were detected in ten cases. Conclusion The non hemorrhagic contusion of corpus callosum is a relatively rare species. These lesions can′t be found on CT images, while MRI is the best tool for detecting them. SE or FSE T 2WI is the main sequence for demonstrating. These lesions could be seen more clearly on FLAIR sequence. The isointense or slight hypointense T 1WI signal and hyperintense T 2WI signal of corpus callosum after head injury is the typical MR imaging signs.

Objective To study CT and MRI features and classification of brain schistosomiasis granuloma. Methods CT and MRI data of 30 cases of brain schistosomiasis granuloma were reviewed.All cases were proved by the surgery or pathological examination and clinical laboratory test.There were 20 males and 10 females, and their age ranged from 5 to 58 years, mean 29.2 years.Plain and enhanced CT were performed in all patients with GE MAX 640 scanner.Ten patients were examined by plain and enhanced MRI with GE Signa profile 0.2 Tesla open scanner.Results The lesions located in supratentorial region in 27 cases and in infratentorial region in 3cases.The nodules were isodense or slight hyperdense on CT plain scan, iso or hypointense on T_1WI, hyperintense on T_2WI, Slight hyperintense on FLAIR.After the contrast material was injected intravenously, CT and MRI findings were multiple or single enhanced nodules at the cortical or subcortical area.There were four types of imaging features: (1) multiple small nodules in 5 cases (presenting as bright stars in the dark sky); (2) single large nodule in 8 cases; (3) mixed nodules in 14 cases; (4) circle-enhanced nodules in 3 cases.Conclusion The brain schistosomiasis granuloma has typical CT and MRI findings.CT and MRI classification is not only helpful to its diagnosis and differential diagnosis, but also might be useful for the choice of clinical treatment.

Pupose To explore the role of histogram analysis of apparent diffusion coefficient (ADC) maps obtained from multiple b value diffusion weighted imaging (DWI) in the assessment of progression of high-grade glioma (HGG) treated with chemoradiotherapy so as to determine the optimal b value.Materials and Methods Forty-one consecutive patients with HGG proved histopathologically who had undergone concurrent chemoradiotherapy at Second Hospital of Hebei Medical University from September 2014 to October 2015 were enrolled in the study.All the subjects underwent diffusion weighted MR imaging before and after therapy with b values of 0,1000,2000 and 3000 s/mm2.Based on the clinical and radiographic follow-ups,the patients were divided into progression and nonprogression groups.ADC maps were calculated according to hyperintense FLAIR lesions after completion of chemoradiotherapy.The fifth percentile (C5) in terms of cumulative histograms in different b-value ADC maps in multiple b value DWI was calculated,and the C5 of each ADC map between progression and non-progression groups was compared.Moreover,receiver operating characteristic analysis was used to determine the best cutoff values and diagnostic accuracy for predictors in the differentiation of true progression from non-progression.Results The C5 of all different b value ADC maps were significantly lower in the progression group than those in the non-progression group (P＜0.01).In terms of the accuracy of assessing the progression after therapy,the C5 in the high b value ADC maps was significantly higher than that in the low b value ADC maps.The area under the receiver operating characteristic curve (AUC) of the C5 was 0.717,0.832,0.909,0.933 and 0.937 respectively in the 5 ADC maps [ADC(1000/0),ADC(2000/0),ADC(30000/0,ADC(3000/1000) and ADC(3000/2000)].When the cutoff value of C5 was 405.6 mm/s2 in ADC(3000/2000) map,the sensitivity,specificity,positive predictive value and negative predictive value were 90.9％,89.7％,89.9％ and 91.0％,respectively.Conclusion The C5 in ADC map can effectively differentiate tumor progression of HGG,and that of high b values have higher accuracy.

Objective To evaluate the application value of ADC of different b-value ADC maps in multiple b-value DWI for assessment of early treatment response and detection of tumor progression.Methods Totally 47 postoperative patients with glioma were enrolled.All of them accepted chemoradiotherapy after operation.Conventional MRI and multiple b-value DWI (b=0,1 000,2 000,3 000 s/mm2) scans were performed.The mean and minimal ADC values (ADC and ADCrmin) were measured in 5 differrent corresponding ADC maps,such as ADC(1 000/0),ADC(/2 000/0),ADC(3 000/0),ADC(3 000/1000） and ADC(3 000/2 000).And the relative values (rADC and rADCmin) were calculated.The differences of ADC values among different reaction types (complete response,partial response,stable disease and progressive disease)and between progressive and non-progressive groups were compared.ROC analysis was used to determine the best cutoff values and diagnostic efficiency of ADC value for diagnosis of tumor progression.Results The rADC in ADC(3 000/0),ADC(3 000/1000） and ADC(3 000/2 000) maps were significantly different among different response types and between progressive group and non progressive group (all P＜0.05).The ADC in ADC(3 000/1000） and ADC(3000/2 000) maps were significantly different among different response types and between progressive group and non-progressive group (all P＜0.05).The ADC and rADC in ADC(3 000/2 000) map had the maximum area under curve (0.86,0.84).When ADC and rADC in ADC3 000/2 000 map were 408.65 × 10-6 mm2/s and 1.12,the sensitivities and specificities were 89.3 ％0,71.0 ％00 and 92.9 ％,77.4 ％,respectively.Conclusion The ADC and rADC in high b-value ADC maps are helpful to discriminate the early treatment response from tumor progression,which can provide valuable information for identification of tumor progression of glioma after treatment.

Objective To investigate the effect of different injection rate of contrast medium on the quality of multislice spiral CT portography(SCTP). Methods Thirty patients with no prominent difference in the age and weight randomly divided into 3 groups (10 cases each group) underwent contrast-enhanced CT scan of abdomen. Non-ionic contrast medium (300 mgⅠ/ml, 1.5 ml/kg) was injected through antebrachium veins with power injector at the rates of 2.0 ml/s,3.0 ml/s and 4.0ml/s. Arterial phase acquisi-tion was made using the software of automated bolus triggering with a ROI placed on abdominal aorta when 100 HU was reached, and 7 seconds and 20 seconds later, portal phases were done respectively. The attenuations of portal vein(PV) and hepatic parenchy-ma of 3 groups were measured on source images. Then the oblique axial and coronal maximum intensity projection(MIP) maps were reconstructed at workstation and PVs were observed. Statistics analysis was made with software of SPSS 11.5. Results The attenu-ations of PV in 2.0ml/s, 3.0 ml/s and 4.0 ml/s groups were (150.80±21.16)HU, (170.90±17.26)HU and [181.90±22.88) HU respectively. There was obvious difference between 2.0ml/s and 4.0ml/s groups for atteuation of PV(P=0.017). The differences of CT attenuation of PV-hepatic parenchyma in three groups were (50.20±17.40) HU, (67.10±23.08) HU and (76.20±22.75) HU respectively. Prominent difference was also found between 2.0 ml/s and 4.0 ml/s groups(P=0.039). The grades of segment of PV displayed on SCTP maps were 4.20±1.14,4.90±0.99 and 5.50±0.53 in 2.0 ml/s,3.0 ml/s and 4.0 ml/s groups respectively, which were of obvious differences between them (P=0.013). Conclusion Injection rate of contrast medium dose influence the quality of SCTP of PV,SCTP quality is best with velocity of flow at 4.0 ml/s.