Head dual energy-computed tomography angiography versus neuro-digital subtraction angiography

Dual-energy X-ray absorptiometry provides two modes of head computed tomography （CT） angiography scanning： neuro-digital subtraction angiography and dual-energy CT angiography （DE-CTA）. Previous studies have compared image quality, radiation exposure, and bone removal between neuro-digital subtraction angiography and DE-CTA. However, the number of cases was relatively small. The present study examined 300 suspected cases of cerebrovascular disease and observed the methods and duration of post-processing, examination time, and data volume. Results demonstrated similar image quality between the two methods, but lower radiation doses and shorter examination time in DE-CTA. DE-CTA allowed for faster and more stable scanning performance and post-processing methods, facilitating accurate and direct diagnosis of cerebrovascular disease.

NON-INVASIVE IMAGING OF CORONARY ARTERY WITH 16-SLICE SPIRAL COMPUTED TOMOGRAPHY

To evaluate the value of 16-slice spiral CT in the demonstration of coronary artery and in the diagnose of coronary artery stenosis. Methods Plain and enhanced CT scans were performed with a 16-slice CT scanner (Sensation 16, Siemens, Germany) in 230 patients with suspected coronary heart disease (CHD). Parameters of the plain scan were: 120 kV, 133 mA, slice col-limation 16 mm×1.5 mm, rotation time 0.42 seconds, increment 1.5 mm, and slice width 3 mm. Parameters of the enhanced scan were: 120 kV, 500 mA, slice collimation 16 mm×0.75 mm, rotation time 0.42 seconds, increment 0.5 mm, and slice width 1 mm. Enhanced CT scan was performed with a rapid intravenous injection of 100 mL iothalamate meglumine (Ultravist) (370 mgI/mL) or Omnipaque (350 mgI/mL) and 30 mL 0.9% NaCl chaser bolus at a flow rate of 3.5 mL/s. Calcium scoring with plain scan images and two and three dimensional reconstruction with enhanced scan images were made in all cases, among which 30 cases underwent conventional coronary angiography. Demonstration of coronary arteries and their stenosis were evaluated and the factors that might influence the image quality were analyzed. Results Coronary calcium scores were calculated and coronary artery was demonstrated in our study. In the evaluationof image quality with volume rendering technique (VRT) images, 78.3% of the images were of the first class, 12.2% the sec-ond class, and 9.6% the third class. Multi-planar reconstruction (MPR) and maximal intensity projection (MIP) were better than VRT in the demonstration of small branches. The image quality was related to the heart rate, with or without arrhythmia, and breath-hold ability of patients. Comparative study of the stenosis of coronary arteries in 30 cases showed that the sensi-tivity and specificity of 16-slice coronary CT angiography (CTA) to diagnose significant stenosis were 95.8% and 94.8% resp-ectively. Conclusion As a non-invasive and quick method, 16-slice coronary CTA is sensitive and specific to diagnose the stenosis of coronary arteries and can be used as a screening method in the diagnosis of CHD.

Noninvasive Detection of Coronary Artery Stenosis Using 16-slice Spiral CT: a Comparison with Selective X-ray Coronary Angiography

The role of 16-slice spiral CT was selective X-ray coronary angiography （SCA） who were suspected of having coronary heart evaluated in the diagnosis of coronary stenosis, with serving as the reference standard. Sixty-five patients disease, without percutaneous transluminal coronary angioplasty or coronary bypass-grafting, were investigated using 16-slice CT. Eight patients with pre-scan heart rate of more than 80 beats/min were given β-blockers. After the retrospectively ECG-gated axial imaging reconstruction, volume redering （VR）, multi-planar reconstruction （MPR）, curved MPR and maximum intensity projection （MIP） were used to reconstruct. Every segment of coronary artery with a diameter ≥1.5 mm was assessed, and the presence on CT with a stenosis exceeding 50 % diameter reduction was compared with that on SCA. The reasons which lead to some segments unevaluable were analysed. Compared with SCA, 93 % coronary segments and 94 % main branches were evaluable. Residual cardiac motion artifacts, severe calcification and poor opacification made 58 %, 28 % and 14 % of the remaining 60 segments unevaluable respectively. Without routine administration of β-blockers, good coronary imaging quality can be acquired using 16-slice spiral CT. It is a reliable noninvasive method for detection of obstructive coronary artery disease.

0D-1D coupling model and 3D fluid-structure interaction model based on coronary CT angiography for displaying hemodynamic characteristics of coronary artery stenosis

Objective To observe value of 0D-1D coupling model and 3D fluid-structure interaction(FSI)model based on coronary CT angiography(CCTA)for displaying hemodynamic characteristics of coronary artery stenosis.Methods Based on CCTA data of the stenosed left anterior descending branch(LAD)in a patient with coronary heart disease,an 0D-1D coupling model and 3D FSI model were built,respectively.Then hemodynamic characteristic indexes,including the pressure,flow velocity and wall shear stress(WSS)were obtained in every 0.01 s during 1 s at 5 sampling points(i.e.sampling point 1—5)using these 2 models,respectively,and the consistencies of the results between models were evaluated with Spearman correlation coefficient r s.Results The time consuming for construction of 0D-1D coupling model and 3D FSI model was 0.033 min and 704 min,respectively.Both models showed basically distribution of the pressure,flow velocity and WSS of the stenosed LAD.For more details,the pressure at the stenosed segment of LAD and the proximal segment of stenosis were both higher,which gradually decreased at the distal segment of stenosis,and the flow velocity at the proximal segment of stenosis was in a relatively slow and uniform condition,with significantly increased flow velocity and WSS at the stenosed segment.Compared with 3D FSI model,0D-1D vascular coupling model was relatively unrefined and lack of distal flow lines when displaying blood flow velocity.For sampling point 2 at the stenosed segment of LAD,no significant consistency for pressure between 2 models was found(P=0.118),but strong consistency for the flow velocity and WSS(r s=0.730,0.807,both P<0.05).The consistencies of pressure,flow velocity and WSS between 2 models at the proximal and distal segment of stenosis,i.e.1,3—5 sampling points were week to moderate(r s=0.237—0.669,all P<0.05).Conclusion 0D-1D coupling model exhibited outstanding computational efficiency and might provide relatively reasonable results,while 3D FSI model showed higher accuracy for details and streamline when simulating LAD stenosis.

Role of Early Arterial Phase Multislice Helical CT Angiography in Evaluation of Hepatocellular Carcinoma

Objective: To investigate the clinical application of early arterial phase multislice CT angiog raphy (MSCTA) of hepatic vessels in evaluation of middle or advanced stage hepatocellular carcinoma. Methods: Trigger Bolus program was used to carry out MSCTA in early and late arterial phases and portal vein phase with single breath holding. Hepatic vessels were reconstructed from the original images of early arterial phase by post processing. The blood supply of tumor and normal liver tissue and the appearances of venous thrombosis and arteriovenous shunts were analyzed. Results: The MSCTA with early arterial phase could perfectly display the origin, shape and amount of feeding vessels to normal liver tissue and tumor in middle or advanced stage hepatocellular carcinoma. It had the ability of displaying the arteriovenous shunts better than that in conventional dual phased liver scanning. Conclusion: MSCTA of hepatic vessels with early arterial phase acquisition using multislice helical CT in middle or advance stage hepatocellular carcinoma has favorable and promising application. It can be used as an imaging method for comprehensive assessment of the hepatocellular carcinoma before treatment.

Clinical value of multi-slice helical CT angiography in diagnosis of cerebral vascular diseases

Objective: To evaluate the clinical value of multi-slice helical CT angiography (MSCTA) in diagnosis of cerebral vascular diseases. Methods: 52 patients with cerebral vascular diseases were examined with GE Light Speed 4-slice and 16-slice helical CT. Pitch: 0.5–3, slice thickness: 0.625–1.25 mm, adult injection dosage: 90–100 mL, children injection dos- age: 2 mL/kg, injection rate: 2.5–4.0 mL/s, delay time: 15–22 s. Intelligent track scan (Smart prep Rx) were adopted in parts of these cases. Three-dimensional cerebral vascular images were processed at ADW 3.1 and ADW 4.2 workstation. Results: MSCTA could clearly display spacious anatomic details of cerebral aneurysm, including its origin, size, neck width, and trend etc. MSCTA results of 19 cases were consistent with those of operations. The diameter of the smallest cerebral aneurysm shown in our research was about 3 mm. As a non-invasive examination, MSCTA could also be applied in post-operational evaluation of cerebral aneurysm by observing the location of silver clip and the distant vessels. Besides, MSCTA could be used to diagnose arteriovenous malformation and moyamoya disease. Of all the three-dimentional imaging methods, volume rendering (VR) is the best means to display the cerebral vascular diseases. Conclusion: As a non-invasive examination, MSCTA plays an important role in detection, pre-operational and post-operational evaluation of cerebral vascular diseases.

Multislice spiral CT angiography in evaluation of liver transplantation candidates

BACKGROUND: Orthotopic liver transplantation has be- come the treatment of choice for patients with end-stage liver disease. This study was designed to study whether multislice spiral CT angiography (MSCTA) could be used for preoperative evaluation for orthotopic liver transplanta- tion candidates. METHODS: Eighty consecutive potential candidates for liver transplantation were evaluated with dual-phase three-di- mensional CT angiography (3DCTA). The arterial-phase was used to create vascular maps of the celiac axis (inclu- ding the origin of the hepatic common artery, left gastric artery and splenic artery) and origin of the superior mesen- teric artery. The portal venous-phase was used to analyze portal vein thrombosis and collateral vascularization of the portal vein. Statistical analyses were made using the chi- square test for differences between hepatic arterial anatomy of 80 patients and Michel's anatomy of 200 patients. Appearance of MSCTA and operative results of 16 patients were analyzed. RESULTS; Sixty-two patients (77.5%) showed conven- tional and 18 (22.5%) nonconventional hepatic arterial anatomy. A significant difference was found between the two groups in anatomy of the hepatic artery (P <0.05). Celiac axis stenosis was observed in 6 patients, SA aneu- rysm in 2, small-caliber hepatic arterial vessels in 2, and portal vein thrombosis in 15. Vascular structures of 16 ope- rative patients were well defined. CONCLUSION: As a noninvasive examination, MSCTA can provide a comprehensive preoperative vascular evalua- tion for liver transplantation candidates.

The value of CT pulmonary angiography to the diagnosis of right ventricular dysfunction due to acute pulmonary embolism:compared with ultrasonographic cardiography

To analyze the value of CT pulmonary angiography（CTPA） in assessing right ventdcular dysfunction（RVD） after acute pulmonary embolism. Methods：Thirty-six patients with CTPA-confirmed PE who underwent ultrasonic cardiography（UCG） within the ensuing 24 hours were retrospectively reviewed. According to the severity of the disease, the patients were divided into the massive PE group（24 cases） and non-massive PE group（12 cases） respectively. CT scans were analyzed for findings suggestive of RVD. Scans were considered positive for RVD if the right ventricle was dilated（RVd/LVd 〉 1） or if the interventricular septum was straightened or deviated towards the left ventricle. Results were then compared with the results of UCG to estimate the value of CTPA in detecting RVD associated with PE, Results：In all cases, compared with UCG, the diagnostic sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value, and negative predictive value of CTPA was 84.61%, 78.26%, 3.892, 0.197, 68.75% and 90% respectively. Kappa value was 0.60, which suggested moderate agreement between CTPA and UCG in the whole level. In the massive PE group, the diagnostic sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value, negative predictive value of CTPA was 84.61%, 72.73%, 3.103, 0.212, 78.57% and 80% respectively. Kappa value was 0.58, which suggested moderate agreement between CTPA and UCG in the massive PE group. In the non-massive PE group, the diagnostic specificity of CTPA was 83.33%. By statistics, the value of RVd/LVd had significant difference between the massive PE and the non-massive PE group. Conclusion：CTPA can reliably detect RVD through the evaluation of cardiac morphology. However, this result requires confirmation using a larger prospective cohort study.

The dynamic study of the pulmonary artery obstruction degree and the right ventricular function in massive pulmonary embolism on CT pulmonary angiography

Objective： To analyze the value of CTPA in assessing the dissolve of embolus and the function of the right ventricle dynamically. Methods：Twenty-three cases of massive pulmonary embolism were analyzed retrospectively. The pulmonary artery obstruction index and the right ventricular function parameters were collected and analyzed on CTPA before thrombolytic therapy, 24 hours and 14 days after therapy, respectively. Results：The pulmonary artery obstruction index decreased gradually, and there was significant difference before therapy, 24 hours and 2 weeks after therapy. Twenty-four hours after therapy, the maximal short axes diameter and the maximal transverse area of right ventricle（RVd, RV~） decreased significantly, the maximal short axes diameter and the maximal transverse area of left ventricle（LVd, LVs） increased significantly, and the RVd/LVd, RVs/LVS decreased apparently. The pulmonary artery symbolic pressure before and 24 hours after therapy were apparently different. There was no significant difference between azygos vein, the super vena cava, the main pulmonary artery and vein reflux before and after therapy. Conclusion：CTPA can evaluate the pulmonary artery obstruction degree and right ventricular function dynamically.

双源CT冠状动脉造影评价冠状动脉狭窄

目的评价双源CT(DSCT)冠状动脉造影诊断冠状动脉狭窄的准确性。方法收集104例临床疑诊或确诊冠心病并于30日内先后接受DSCT冠状动脉造影检查和导管法冠状动脉造影(CAG)患者,以CAG诊断结果作为金标准,分别评估DSCT诊断冠状动脉狭窄性病变(<50%、≥50%和≥75%)的价值。结果 CAG显示1296段冠状动脉。DSCT可评估的冠状动脉为1217段,可评估率为93.90%(1217/1296);诊断<50%、≥50%和≥75%狭窄的敏感度分别为79.12%(144/182)、84.73%(172/203)和89.83%(106/118),特异度分别为97.33%(802/824)、99.21%(1006/1014)和99.82%(1097/1099),阳性预测值为86.75%(144/166)、95.56%(172/180)和98.15%(106/108),阴性预测值为95.48%(802/840)、97.01%(1006/1037)和98.92%(1097/1109),准确率为94.04%(946/1006)、96.80%(1178/1217)和98.85%(1203/1217)。钙化斑块是导致血管不可评估及误诊的主要原因。结论 DSCT冠状动脉造影判断冠状动脉狭窄程度的准确性较高,可作为临床筛查冠心病的较为可靠的方法。

Comparison in Diagnosing the Postoperative Recurrence of Hepatocarcinoma between MSCT and DSA

Objective： To evaluate the value of MSCT and DSA in diagnosing the postoperative recurrence of hepatocellular carcinoma by analyzing the results of these two image examinations. Methods： Seventytwo patients with postoperative recurrence of hepatocellular carcinoma were subjected to MSCT and DSA of their livers. The interval of two examinations was 2 to 14 days. Results： In 51 cases （70.83%）, the recurrent lesions were multiple small nodules （type Ⅰ）, 9 cases （12.36%） were single nodule （type Ⅱ）, and the remaining 12 cases （16.81%） were unequal nodules （type Ⅲ）. The results of two examinations were discrepancy in 10 patients. In 7 cases having positive results in DSA, the number of small nodules in 5 cases displayed by DSA was more than that by MSCT, and 2 cases had negative results in MSCT. In 3 patients having positive results in MSCT, number of small nodules in 2 cases displayed by MSCT was more than that by DSA and 1 case had negative results in DSA. Conclusion： MSCT and DSA had difference in displaying the postoperative recurrent lesions of hepatocellular carcinoma. The combined application of MSCT and DSA would be beneficial to improve the diagnosis of recurrent lesions.

Research on focal nodular hyperplasia with MSCT and postprocessing

AIM： To investigate and evaluate the pathological features and diagnostic value of focal nodular hyperplasia （FNH） with multiection spiral computed tomography （MSCT） and postprocessing. METHODS： A total of 25 patients with FNH who had undergone MSCT and postprocessing were included in the investigation. All patients had been pathologically or clinically confirmed with FNH. A number of 75 cases of hepatic carcinomas, hemangiomas and adenomas were randomly selected at a same period for a comparative study. RESULTS： There was a single focus in 22 cases and multiple foci in 3 cases. On the plain scan, 17 lesions showed hypodensity, 7 isodensity and 4 hyperdensity （the case with fatty liver）. With contrast, 28 lesions were enhanced evenly or in the nodules in the arterial phase; 13 lesions still showed hyperdensity, 11 lesions isodensity and 4 lesions hypodensity in the parenchymatous phase; in the delayed phase only 5 lesions showed hyperdensity but 9 lesions showed isodensity or slight hypodensity and 14 lesions showed hypodensity. Twelve lesions of 28 had central asteroid scars. Thickened feeding arteries in postprocessing were seen in 24 lesions, and were integrated into the parenchymatous lesions with a gradual and smooth course. On the contrary, there were no artery penetrated into the lesion found in any of comparative hepatic tumors. CONCLUSION： Doctors could make a correct diagnosis and differentiation of FNH on evaluation of the characteristic appearance on MSCT with postprocessing,

The Clinical Characteristics and Imaging Findings of Morning Glory Syndrome

To investigate the features of CT, ultrasonography and fundus fluorescein angiography （FFA） of morning glory syndrome, the data on CT, A/B-scan ultrasonography and fundus fluorescein angiography （FFA） were retrospectively analyzed in 8 cases of morning glory syndrome （MGS）. Among those cases, 6 were examined with CT, 4 with FFA and 8 with A/B-scan ultrasonography. Results showed that the characteristics of CT, A/B-scan ultrasonography and FFA in MGS included： （1） The attachment spot of optic nerve became thin and vitreous body protruded to the posterior wall of eyeball with a spherical shape on CT image; （2） in the early period of FFA, hypofluorescence appeared on the optic, the abnormal arteriae and veins around the optic papilla were displayed clearly and in the late period, optic disc was stained with fluorescein; （3） on B-scan ultrasonogram, the vitreous cavity extended to the posterior pole and optic papilla, and projected to the basal part of muscle cones and thus the posterior part of vitreous cavity looked like an upside-down bottleneck. Sometimes the echogenic band of retinal detachment could also be seen. On A-scan ultrasonogram, both vitreous cavity and bottleneck showed no ultrasonic echoes and presented a base line without any evident wave crest. It is concluded that CT, A /B-scan ultrasonography and FFA could show the imageological features of MGS from different aspects, which helps clinicians to differentiate it from other diseases such as optic disc coloboma. CT and A /B-scan ultrasonography, in particular, are considered to be reliable imageological methods for the accurate diagnosis of MGS and are superior to the traditional techniques.

下肢动脉瘤的MDCTA诊断

目的:探讨MDCTA在下肢动脉瘤病变中的诊断价值。方法:回顾分析了18例临床诊断下肢动脉瘤病例的四排螺旋CTA影像。三种不同的重组后处理方式包括MIP,VR及CPR,以及横断位图像均被用于回顾性分析。结果:18位患者中共检出真性动脉瘤15例(23个),假性动脉瘤3例。MDCTA较好地显示了所有瘤腔及腔壁的血栓。其中8例真性动脉瘤和3例假性动脉瘤均经手术证实。结论:下肢动脉MDCTA成像技术安全可靠,在下肢动脉瘤病变的影像学诊断中有着较好的诊断价值,能够基本替代创伤性的血管造影。

Three-dimensional CT angiography and surgical correlation in the evaluation of intracranial aneurysms

OBJECTIVE: To evaluate the diagnostic accuracy of three-dimensional CT angiography in the surgical treatment of intracranial aneurysms. METHODS: Twenty-four patients suspected of intracranial aneurysms underwent routine catheter four-vessel angiography, three dimensional CT angiography (3D-CTA), magnetic resonance angiography (MRA) or conventional digital subtraction angiography (DSA). RESULTS: A total of 28 aneurysms were detected by CT angiography in this study. Twenty-one patients each had a single aneurysm, two patients each had two aneurysms, and one had three aneurysms. The shapes of aneurysms revealed by 3D-CTA were round in 20 lesions, elliptical in 5, and 1 obulated in 3. Of the 24 lesions which were completely disclosed during surgery, the shapes correlated well with the 3D-CT angiograms. The mean diameter of the aneurysmal neck was 5.9 mm in 3D-CTA images, with the smallest being 1.6 mm and the largest 13.7 mm. The size was very close to the actual size measured at surgery (P

Cerebral artery evaluation of dual energy CT angiography with dual source CT

Background Conventional computed tomography angiography （CTA） is time consuming, user-dependent and has poor image quality in skull base region. This study assessed the feasibility of a new method, dual energy CTA for depicting the cerebral artery.Methods Phantom scan was done with head CTA sequences on dual source CT and 64 spiral CT for radiation dose calculation. Dual energy CTA was done with dual source CT on 36 patients who were suspected of having cerebral vascular disease. Three series axial images in 0.75 mm thick, 0.4 mm increment were acquired, which were named with 80 kV, 140 kV and merged images; 80 kV and 140 kV images were transferred into dual energy software, and maximum intensity projection （MIP） image was generated quickly by dual energy bone remove （DEBR group）; merged images were transferred into In Space software to acquire MIP image through manual conventional bone remove （CoBR group）. Post processing time and reading time were compared. Image qualities of the two groups were compared, mainly focusing on skull base segments of internal carotid artery and bone subtraction. ANOVA and SNK tests were applied for radiation dose comparison. Student＇s t test and Wilcoxon rank sum test were applied for assessing differences between data for significance. Cohen＇s kappa was used for interobserver agreement. Results Radiation dose of phantom scan showed dual energy CTA was between digital bone subtraction and conventional CTA. The post processing time and reading time were much shorter in DEBR than CoBR, and image quality in skull base was much higher in DEBR than CoBR （P〈0.01）. There was no significant difference for suprasellar vessels between two groups （P〉0.5）. Interobserver agreement for all vessel segments was excellent （kappa=0.97）. Conclusions Dual energy CTA is a reliable, new modality for depicting cerebral artery, overcoming the limitation of conventional CTA in the skull base region. It can save much time in post processing and reading than conventional CTA.

Assessment of the anterior spinal artery and the artery of Adamkiewicz using multi-detector CT angiography

Background Damage to the spinal cord after the treatment of the descending thoracic and thoracoabdominal aortic aneurysms is an uncommon but devastating complication. The artery of Adamkiewicz （AKA） is the principal arterial supply of the anterior spinal artery （ASA） in the lower thoracic and lumbar level. The purpose of this study was to evaluate the visualization of the anterior spinal artery and the artery of Adamkiewicz, the affecting factors for the detection rate using multi-detector row CT （MDCT）. Methods Ninety-nine consecutive patients （31 women and 68 men; age range, 25-90 years; average age 61.3 years）, with suspicion for thoracic aortic lesions necessitating surgical intervention （31 aortic aneurysm, 45 dissection, 5 intramural hematoma, and 18 normal）, underwent CT angiography from the aortic arch to the aortic bifurcation. Transverse sections, multiplanar reformations and thin maximum intensity projections were used to assess the ASA and AKA. The level of the ASA and AKA origins and CT acquisition parameters were recorded. The contrast-to-noise ratio of the image, an index of the mass of the Tll body （vertebral mass index）, the subcutaneous fat thickness, and the CT value within the aortic arch and at the Tll level were measured. The detection of the ASA and AKA were evaluated relative to the acquisition parameters, scan characteristics, and aortic lesion type. Differences were assessed with the Wilcoxon rank-sum and t tests. Results The ASA was visualized in 51 patients （52%） and the AKA in 18 patients （18%）. The ASA was identified in 36/67 patients （54%） with 1.25 mm thickness and in 15/32 patients （47%） with 2.5-3.0 mm thickness. This difference did not achieve significance （P=0.13）. The detection rate of the ASA and the AKA was influenced by the vertebral mass index and the contrast-to-noise ratio （P〈0.05）. The amount of subcutaneous fat affected the detection rate of the ASA （P 〈0.05） but not the AKA. In CT scans of ASA detection, the mean CT values in the aorta at the arch and at Tll were 360 and 358 HU, respectively, whereas in CT scans without ASA detection, the CT values in the aorta at the arch and at Tll were lower （P 〈0.05）, 297 and 317 HU, respectively. Conclusions The ASA and AKA were less frequently detected in our cohort than previous reports. The visualization of the ASA and AKA was significantly affected by aortic enhancement, the ＂vertebral mass index＂, and the contrast-to-noise ratio. Chin Med J 2009; 122（2）： 145-149

Clinical significance of multislice spiral CT scans in hepatic veins occlusion in Budd-Chiari syndrome

Background Budd-Chiari syndrome with hepatic vein occlusion （HVBCS） can induce severe portal hypertension and liver damage. We retrospectively analyzed hepatic CT features of HVBCS and evaluated the usefulness of triphasic enhancement of CT examinations and CT angiography （CTA） in its diagnosis. Methods Twenty-five cases with HVBCS, confirmed by digital subtraction angiography （DSA）, received a triphasic enhancement CT scan within one week before DSA. The CTA images of the relevant blood vessels were reconstructed with maximum intensity projection, volume rendering and oblique reformat techniques. Results Compared with DSA, the detection rate of transverse CT and CTA images for abnormal hepatic vein were 81.7% （58/71） and 95.8% （68/71） （X^2=7.044, P=-0.008）, for membranous obstruction were 47.4% （9/19） and 84.2% （16/19） respectively （X^2 =5.729, P=-0.017 ）, for segmental obstruction were 88.0% （22/25） and 100% （25/25） respectively （X^2=1.418, P=-0.234）. The detection rates for hepatic vein stenosis were 100% with each method. Diffuse hepatomegaly was found in all 6 cases in acute phase and 3 of 19 cases in chronic phase who had severe obstruction of three hepatic veins without patent intrahepatic collaterals. The other 16 cases in chronic phase had hepatatrophia to different extents related to the obstructed hepatic vein. All in acute phase and 15 in chronic phase presented typical patchy enhancement initially in caudate lobe and perihilar areas and enlarged with time delay. In all cases, parenchyma areas with atrophy, necrosis and congestion demonstrated lower and later enhancement. In all the parts, which had normal enhancement at least one patent outflow hepatic vein, accessory hepatic vein or collateral vessel was detected.Conclusion Dynamic enhancement CT examination by multislice spiral CT not only could improve the diagnosis of HVBCS by CTA technique, but also could noninvasively provide anatomical information and reveal damage to the hepatic parenchyma.

Diagnostic accuracy and its affecting factors of dual-source CT for assessment of coronary stents patency and in-stent restenosis

Background In-stent restenosis is a common complication after stent implantation. However, the assessment of stent lumen in computed tomography （CT） coronary angiography is limited by multiple factors. Our study aimed to evaluate the accuracy and the suspected affecting factors in diagnosing coronary in-stent restenosis by dual-source CT （DSCT） compared with coronary angiography. Methods One hundred and fifteen stents in 50 patients were evaluated with DSCT before coronary angiography for the detection of coronary in-stent restenosis （〉 50% luminal narrowing）. Patency of each stent was analyzed by two independent expert radiologists blinded to the results of coronary angiography. The relationship between diagnostic accuracy and the suspected factors including age, body mass index （BMI）, heart rate, variation of heart rate, radiation dose, image quality, location and stent characteristics （type, material, diameter, length and strut thickness） was assessed with both univariate and multivariate analysis. The fitting of a Logistic regression model was evaluated using a receiver operating characteristic （ROC） curve. Results Mean stent diameter was （2.9±0.4） mm. Sensitivity, specificity, positive and negative predictive values and accuracy of DSCT in detection of in-stent restenosis were 69.2%, 91.2%, 50.0%, 95.9%, and 88.7%, respectively. In a subgroup of stents with a diameter 〉3.0 mm, sensitivity, specificity, positive and negative predictive values and accuracy were 100.0%, 96.5%, 75.0%, 100.0%, and 96.8%, respectively. Stent diameter 〈3.0 mm and poor image quality were associated with poor diagnostic accuracy （P 〈0.05）. The area under curve of ROC was 0.79. Conclusion DSCT can provide high accuracy for the assessment of in-stent restenosis in stents with a diameter 〉3.0 mm, and can play an important role in ruling out in-stent restenosis.

Diagnostic value of CTA and MRA in intracranial traumatic aneurysms

Objective： To investigate the diagnostic value of computerized tomographic angiography （ CTA ） and magnetic resonance angiography （ MRA ） for intracranial traumatic aneurysms （TAs）. Methods： CTA and MRA of six patients with intracranial TAs verified by digital subtraction angiography （DSA） and surgery were retrospectively analysed. All patients were examined by nonenhanced computerized tomography （CT） and two by CTA. The source data were reconstructed by volume rendering （VR） and multi-planar reconstruction （MPR） from CTA. Four of them had maxhnum intensity project （MIP） from MRA. Results ： Of the six patients, a total of seven TAs were detected by CTA and MRA examinations. Five cases had only one TA and one case had two TAs. The average diameter was 2.3 cm （1.1-3.3 cm）. CTA demonstrated two TAs appeared at the cavernous segment of the internal carotid artery （ICA） and the middle cerebral artery （MCA） respectively. MCA TA was definitely and dearly demonstrated on VR images, whereas VR images failed to depict the cavernous ICA TA, which was detected on MPR images. Two TAs were found irregular saccular shape,irregular margin of parent artery and wide neck on CTA. Four MRA examinations demonstrated five TAs, including the cavernous segment ICA TAs （2 cases）, the supraclinoid segment ICA TA （1 case ）, and the cavernous segment associated with opposite side of the petrosal segment ICA TA （1 case）. In a cavernous ICA TA, MRA only revealed aneurysm body, whereas aneurysm neck and distal segment of the parent artery were not revealed. In the remaining cases, MRA clearly depicted aneurysm body and parent artery, whereas the neck was not displayed. ICA TAs showed irregular capsnle-like high signal intensity on MRA images. Four TAs exhibited irregular distal segment of the parent artery. TAs at the supraclinoid segment or MCA failed to find fracture signs on nonenhanced CT. Conclusions： Both CTA and MRA examinations are the effective non-invasive method of imageology for diagnosing intracranlal TAs, while CTA is more eligible for diagnosing TAs after nonenhanced CT has demonstrated skull base fractures.