Preoperative diagnosis and operative effect of intracranial aneurysm with three-dimensional computed tomography angiography

BACKGROUND ： Digital subtraction angiography （DSA） is always regarded as the golden standard for diagnosis of intracranial aneurysm; however, the procedure is complex, traumatic, expensive and easy to induce vascular complication. Three-dimensional computed tomography angiography （3D-CTA） can make up deficiencies of DSA; therefore, it is used in clinical therapy wider and wider. OBJECTIVE ： To evaluate the clinical effect of 3D-CTA on disruption and hemorrhage of intracranial aneurysm pre- and post-operation and compare with the effect of DSA. DESIGN ： Auto-control contrast observation SETTING ： Department of Neurosurgery, Shengjing Hospital of China Medical University PARTICIPANTS ： A number of 106 patients with disruption and hemorrhage of intracranial aneurysm were selected from the Department of Neurosurgery, Shengjing Hospital of China Medical University from January 2003 to April 2006. All patients were diagnosed with cranial operation and consent. There were 47 males and 59 females aged from 3-76 years with the mean age of （47±13） years. Among them, 82 patients had extensive subarachnoid hemorrhage （SAH）, 7 had hemorrhage at longitudinal fissure, and 17 had hemorrhage at ambiens cistema and lateral fissure. Moreover, intraventricular hematocele was accompanied on 13 patients and hematom on 9 patients. METHODS： （1） 3D-CTA examination： Siemens SOMATOM Sensation 64 CT was used in this study. The thickness was 1 mm and interval of reconstruction was 0.8 mm. Localizing section was plainly scanned as the standard of canthus line. Scan ranged from 30 mm below sella to 50 mm above sella. Non-ion contrast medium of Omnipaque 350 （concentration of iodine was 350 g/L） was inserted into anterior vein of elbow with 18G trochar retained with high-pressured injectoc pum. The speed was 4.5 mL/s and the total volume was 80-100 mL with the means of 90 mL. Scan started at 10-20 s after injection of contrast medium. Original image was dealt with Leonardo workstation and retreated with Syngo software. Volume rendering and maximum intensity projection were used to reconstructed images, （2） All 106 patients suffered from occlusion of aneurysm clamp. Before operation, 3D-CTA was undertaken and DSA was followed. After operation, patients were rechecked with 3D-CTA. MAIN OUTCOME MEASURES： Comparisons between 3D-CTA and DSA. RESULTS ： All 106 patients were involved in the final analysis. （1） Examination of 3D-CTA and DSA： Among 118 patients with aneurysm, 110 were checked with 3D-CTA and the detected rate was 93.2% （110/118）. Among other 8 cases, 3 were negative and checked again with DSA; 1 had pericallosal aneurysm, 1 ophthalmic aneurysm, and 1 anterior choroidal artery of aneurysm. 3D-CTA results of other 5 cases were suspicious, and then, they were regarded as having aneurysm with DSA. Before operation, correlation among site, body, neck of aneurysm and peripheral anatomic structure were shown sufficiently. After operation, 82 patients were rechecked with 3D-CTA, which was complete occlusion, precise, unobvious constriction, emphraxis or remains as compared with 3D-CTA those pre-operation. （2） Characteristics of 3D-CTA： With multiple vessels and angles, 3D-CTA observed the relationship between aneurysm neck and carried artery and showed thrombosis in cavity of aneurysm, calcification of aneurysm wall and peripheral structure of vessel at the same time. However, DSA could not detect the reactions mentioned above. It could delete image of cranium, simulate image of operative route, eliminate artifact induced by metal, but not distinguish blood stream direction. Meanwhile, posterior communicating artery was always poor during circle of Willis artery showing. CONCLUSION： （1） 3D-CTA is characterized by simple operation and non-invasive showing vascular stereo structure and correlation. Therefore, it is significant for diagnosis and designing plan of operative approach and focal location pre-operation and evaluating effect post-operation. （2） 3D-CTA does not completely replace DSA on the diagnosis of intracranial aneurysm.

Effects of dry-wet cycles on three-dimensional pore structure and permeability characteristics of granite residual soil using X-ray micro computed tomography

Due to seasonal climate alterations,the microstructure and permeability of granite residual soil are easily affected by multiple dry-wet cycles.The X-ray micro computed tomography(micro-CT)acted as a nondestructive tool for characterizing the microstructure of soil samples exposed to a range of damage levels induced by dry-wet cycles.Subsequently,the variations of pore distribution and permeability due to drywet cycling effects were revealed based on three-dimensional(3D)pore distribution analysis and seepage simulations.According to the results,granite residual soils could be separated into four different components,namely,pores,clay,quartz,and hematite,from micro-CT images.The reconstructed 3D pore models dynamically demonstrated the expanding and connecting patterns of pore structures during drywet cycles.The values of porosity and connectivity are positively correlated with the number of dry-wet cycles,which were expressed by exponential and linear functions,respectively.The pore volume probability distribution curves of granite residual soil coincide with the χ^(2)distribution curve,which verifies the effectiveness of the assumption of χ^(2)distribution probability.The pore volume distribution curves suggest that the pores in soils were divided into four types based on their volumes,i.e.micropores,mesopores,macropores,and cracks.From a quantitative and visual perspective,considerable small pores are gradually transformed into cracks with a large volume and a high connectivity.Under the action of dry-wet cycles,the number of seepage flow streamlines which contribute to water permeation in seepage simulation increases distinctly,as well as the permeability and hydraulic conductivity.The calculated hydraulic conductivity is comparable with measured ones with an acceptable error margin in general,verifying the accuracy of seepage simulations based on micro-CT results.

Phase II Clinical Study of Three-Dimensional Printed Coplanar Template Combined with CT-Guided Percutaneous Core Needle Biopsy of Pulmonary Nodules in Elderly Patients

Background: As the population age structure gradually ages, more and more elderly people were found to have pulmonary nodules during physical examinations. Most elderly people had underlying diseases such as heart, lung, brain and blood vessels and cannot tolerate surgery. Computed tomography (CT)-guided percutaneous core needle biopsy (CNB) was the first choice for pathological diagnosis and subsequent targeted drugs, immune drugs or ablation treatment. CT-guided percutaneous CNB requires clinicians with rich CNB experience to ensure high CNB accuracy, but it was easy to cause complications such as pneumothorax and hemorrhage. Three-dimensional (3D) printing coplanar template (PCT) combined with CT-guided percutaneous pulmonary CNB biopsy has been used in clinical practice, but there was no prospective, randomized controlled study. Methods: Elderly patients with lung nodules admitted to the Department of Oncology of our hospital from January 2019 to January 2023 were selected. A total of 225 elderly patients were screened, and 30 patients were included after screening. They were randomly divided into experimental group (Group A: 30 cases) and control group (Group B: 30 cases). Group A was given 3D-PCT combined with CT-guided percutaneous pulmonary CNB biopsy, Group B underwent CT-guided percutaneous pulmonary CNB. The primary outcome measure of this study was the accuracy of diagnostic CNB, and the secondary outcome measures were CNB time, number of CNB needles, number of pathological tissues and complications. Results: The diagnostic accuracy of group A and group B was 96.67% and 76.67%, respectively (P = 0.026). There were statistical differences between group A and group B in average CNB time (P = 0.001), number of CNB (1 vs more than 1, P = 0.029), and pathological tissue obtained by CNB (3 vs 1, P = 0.040). There was no statistical difference in the incidence of pneumothorax and hemorrhage between the two groups (P > 0.05). Conclusions: 3D-PCT combined with CT-guided percutaneous CNB can improve the puncture accuracy of elderly patients, shorten the puncture time, reduce the number of punctures, and increase the amount of puncture pathological tissue, without increasing pneumothorax and hemorrhage complications. We look forward to verifying this in a phase III randomized controlled clinical study. .

Thoracoscopic segmentectomy and lobectomy assisted by threedimensional computed-tomography bronchography and angiography for the treatment of primary lung cancer

BACKGROUND Anatomical segmentectomy has been proposed as a substitution for lobectomy for early-stage lung cancer.However,it requires technical meticulousness due to the complex anatomical variations of segmental vessels and bronchi.AIM To assess the safety and feasibility of three-dimensional computed-tomography bronchography and angiography(3D-CTBA)in performing video-assisted thoracoscopic surgery(VATS)for lung cancers.METHODS In this study,we enrolled 123 patients who consented to undergo thoracoscopic segmentectomy and lobectomy assisted by 3D-CTBA between May 2017 and June 2019.The image data of enhanced computed tomography(CT)scans was reconstructed three-dimensionally by the Mimics software.The results of preoperative 3D-CTBA,in combination with intraoperative navigation,guided the surgery.RESULTS A total of 59 women and 64 men were enrolled,of whom 57(46.3%)underwent segmentectomy and 66(53.7%)underwent lobectomy.The majority of tumor appearance on CT was part-solid ground-glass nodule(pGGN;55.3%).The mean duration of chest tube placement was 3.5±1.6 d,and the average length of postoperative hospital stay was 6.8±1.8 d.Surgical complications included one case of pneumonia and four cases of prolonged air leak lasting>5 d.Notably,there was no intraoperative massive hemorrhage,postoperative intensive-care unit stay,or 30-d mortality.Preoperative 3D-CTBA images can display clearly and vividly the targeted structure and the variations of vessels and bronchi.To reduce the risk of locoregional recurrence,the application of 3D-CTBA with a virtual 3D surgical margin help the VATS surgeon determine accurate distances and positional relations among the tumor,bronchial trees,and the intersegmental vessels.Three-dimensional navigation was performed to confirm the segmental structure,precisely cut off the targeted segment,and avoid intersegmental veins injury.CONCLUSION VATS and 3D-CTBA worked in harmony in our study.This combination also provided a new pattern of transition from lesion-directed location of tumors to computer-aided surgery for the management of early lung cancer.

Numerical analysis of the failure process of soil-rock mixtures through computed tomography and PFC3D models

Soil-rock mixture （SRM） is a unique type of geomaterial characterized by a heterogeneous composition and a complicated structure. It is intractable for the continuum-based soil and rock mechanics theories to accurately characterize and predict the SRM＇s mechanical properties. This study reports a novel numerical method incorporating microfocus computed tomography and PFC3D codes to probe the deformation and failure processes of SRM. The three-dimensional （3D） PFC models that represent the SRM＇s complex structures were built. By simulating the entire failure process in PFC3D, the SRM＇s strength, elastic modulus and crack growth were obtained. The influence of rock ratios on the SRM＇s strength, deformation and failure processes, as well as its internal mesoscale mechanism, were analyzed. By comparing simulation results with experimental data, it was verified that the 3D PFC models were in good agreement with SRM＇s real structure and the SRM＇s compression process, deformation and failure patterns; its intrinsic mesomechanism can be effectively analyzed based on such 3D PFC models.

3D Reconstruction with Spiral Computed Tomography in Choroidal Osteoma

Choroidal osteoma (CO) is a rare, ossifying benign tumor originated in the choroid that typically occurs in otherwise healthy young women (1,2). It is characterized by a yellowish, well demarcated lesion in the juxtapapillary or macular area. The diagnosis is clinical and can be confirmed with the use of fluorescein or indocyanine angiography, optical coherence tomography, computed tomography or magnetic resonance imaging. Choroidal neovascularization or subretinal fluid, the main causes for vision loss, can be treated with laser therapy, photodynamic therapy or intravitreal antivascular endothelial growth factor therapy. We present a case of choroidal osteoma, showing the role of the high resolution 3D spiral computed tomography.

3D-CTA与3D-DSA对颅内动脉瘤影像诊断的对照研究

目的比较三维-螺旋CT血管造影(3D-CTA)和三维-数字减影血管造影(3D-DSA)在颅内动脉瘤诊断中的应用价值。方法对2008年9月至2009年3月收治入院的自发性蛛网膜下腔出血(SAH)患者79例,行3D-CTA、3D-DSA检查。研究并比较CTA和DSA影像特点。结果79例患者,阴性2例,余77例患者共检出83个动脉瘤。3D-DSA与3D-CTA准确性比较,差异无统计学意义。结论对颅内动脉瘤影像学诊断上,3D-CTA和3D-DSA各有优势。

动脉瘤性蛛网膜下腔出血的3D-CTA及3D-DSA影像诊断

目的评价动脉瘤性蛛网膜下腔出血的三维CT血管造影(3D-CTA)及三维数字减影血管造影(3D-DSA)的影像学诊断价值。方法回顾性分析51例动脉瘤性蛛网膜下腔出血患者的双源CTA和DSA影像学资料,将其动脉瘤检出的敏感性、诊断符合率以及动脉瘤特征和载瘤血管的显示进行对比分析。结果51例患者共检出动脉瘤56个。双源CTA检出49例54个动脉瘤,灵敏度为96.1%,符合率为97.4%;DSA检出49例54个动脉瘤,灵敏度为96.1%,符合率为97.9%。直径在3.1～5mm和5.1～10mm之间的动脉瘤的检出上,3D-CTA和3D-DSA相等。结论对动脉瘤性蛛网膜下腔出血诊断上,3D-CTA和3D-DSA各有优势。

Experimental investigation of junction growth of rough contacts using X-ray computed tomography

The real contact area(RCA)of randomly rough contacts has received a great deal of attention because it correlates strongly with friction,lubrication,sealing,and conductivity.Simulations have revealed that the RCA associated with deterministic normal squeezing loads increases when tangential loads are also applied,in a phenomenon called junction growth.However,experimental investigations of the junction growth of randomly rough contacts are rare.Here,we used X-ray computed tomography(CT)to measure junction growth when two aluminum alloy surfaces were in contact.A high-resolution experimental setup was used to apply loads and observe contact behaviors at a resolution of 4μm.The RCA and average contact gaps were computed using a three-dimensional(3D)geometric model constructed from gray CT images using the Otsu thresholding method.The results showed that the RCA increased as the normal load increased.The RCA increased by 22.67%after a tangential load was applied(junction growth),and the average gap decreased by 14.01%after a tangential load was applied.Thus,X-ray CT accurately measured the junction growth as a novel quantitative method.

Influences of Motion Artifacts on Three-Dimensional Reconstruction Volume and Conformal Radiotherapy Planning

Objective ：To investigate the influences of motion artifacts on three-dimensional （3D） reconstruction volume and conformal radiotherapy planning. Methods： A phantom which can mimic the clip motion of lung tumor along the cranial-caudal direction is constructed by step motor, small ball of polyethylene and potato. Ten different scan protocols were set and CT data of the phantom were acquired by using a commercial GE LightSpeedl6 CT scanner. The 3D reconstruction of the CT data was implemented by adopting volume-rendering technology of GE AdvantageSim 6.0 system. The reconstructed volumes of each target in different scan protocols were measured through 3D measuring tools. Thus, relative deviations of the reconstruction volumes between moving targets and static ones were determined. The three-dimensional conformal radiation therapy （3D- CRT） plans and conformal fields were created and compared for a static/moving target with the WiMRT treatment planning system （TPS）. Results：For a static target, there was no obvious difference among the 3D reconstruction volumes when the CT data were acquired with different pitches and slices. The appearance of 3D reconstruction volume and 3D conformal field of a moving target was quite different from that of static one. The maximum relative deviation is nearly 90% for a moving target scanned with different scan protocols. The relative deviations are variable among the different targets, about from -39.8% to 89.5% for a smaller target and from - 18.4% to 20.5% for a larger one. Conclusion ：The motion artifacts have great effects on 3 D-CRT planning and reconstruction volume, which will greatly induce distorted conformal radiation fields and false DVHs for a moving target.

Permeability differences based on three-dimensional geometrical information of void spaces

In this study,the permeabilities of Berea and Otway sandstones were measured under different confining pressures,and porosity was investigated through mercury intrusion porosimetry(MIP).The total porosities of the Berea and Otway sandstones were approximately 17.4%and 25%,respectively.Pore size distributions of each sandstone were almost the same,but the pores in the Otway sandstone were slightly narrower.However,the permeability of the Otway sandstone was smaller than that of the Berea sandstone by one order of magnitude.Three-dimensional(3D)void geometry and geometrical properties of the void spaces relevant to flow were compared to obtain the relation between the permeability differences and porosities of the two sandstones.The 3D geometrical analysis using microfocus X-ray computed tomography(CT)was performed,and the pore geometries of both sandstones were compared using the 3D medial axis(3DMA)method.Pore and throat radii,pore coordination number,tortuosity,number of connecting paths,connecting path volume,and other factors were determined using 3DMA.The Otway sandstone was characterized by a small effective throat/pore radius ratio.Based on the fluid flow mechanism,the lower effective throat/pore radius ratio results in a lower permeability induced by the fluid energy loss,which means that the 3D geometrical shape of void spaces affects the permeability value.

冠状动脉CT血管造影及血清指标对冠心病冠状动脉狭窄程度的评价

目的:探讨冠状动脉CT血管造影(CCTA)及血清脂蛋白相关磷脂酶A2(Lp-PLA2)、血管生成素样蛋白3(ANGPTL3)对冠心病冠状动脉狭窄程度的评价。方法:选取2022年7月至2023年3月河北省胸科医院诊治的102例冠心病患者,按照冠状动脉狭窄程度积分(Gensini积分)情况将其分为轻度组(0分≤Gensini积分≤20分)、中度组(20分<Gensini积分≤60分)及重度组(Gensini积分>60分),每组34例。对比3组患者冠状动脉最小管腔直径(MLD)、狭窄面积百分比(%AS)、狭窄直径百分比(%DS)、最小管腔面积(MLA)、Lp-PLA2及ANGPTL3,根据受试者工作特征(ROC)曲线,预测冠状动脉狭窄程度的诊断效能。结果:重度组MLA、MLD低于中度组和轻度组,而%AS、%DS高于中度组和轻度组,差异有统计学意义(t=6.905、4.083、5.871、6.976、3.387、2.198、2.668、3.505,P<0.05)。重度组Lp-PLA2、ANGPTL3高于中度组和轻度组,差异有统计学意义(t=4.164、8.220、2.575、3.050,P<0.05)。ROC曲线分析显示,MLA、MLD、%AS、%DS、CCTA综合参数、LpPLA2以及ANGPTL3预测冠状动脉狭窄程度的ROC曲线下面积(AUC)值分别为0.838、0.690、0.742、0.801、0.904、0.808和0.807。灵敏度分别为91.20%、91.20%、64.70%、94.10%、97.10%、70.60%和88.20%;特异度分别为76.50%、57.40%、75.00%、50.00%、70.60%、97.10%和70.60%。CCTA综合参数的AUC分别高于LpPLA2和ANGPTL3,但差异无统计学意义(P>0.05)。结论:CCTA及血清Lp-PLA2、ANGPTL3评估冠心病冠状动脉狭窄程度均具有一定效能,且CCTA的预测效能更高。

S^(2)b+S^(3)a联合亚段切除术治疗右上肺后段(S2)和前段(S3)之间肺结节的疗效研究

目的:探讨S^(2)b+S^(3)a联合亚段切除术治疗右肺上叶后段(S;)和前段(S^(3))之间早期非小细胞肺癌等肺结节的可行性与安全性。方法:回顾本中心2015—2020年肺段切除术资料,分析接受S^(2)b+S^(3)a联合亚段切除术的患者结节特征及围术期资料,采用倾向评分匹配获取年龄、性别、结节病理直径相当的右肺上叶切除术病例进行对比研究。结果:共有46例S^(2)b+S^(3)a切除术病例和与之匹配的46例右上叶切除术病例。右上叶组的结节病理恶性程度较S^(2)b+S^(3)a组高(P=0.037),TNM分期更晚(P=0.026),结节深度较S^(2)b+S^(3)a组更深(P=0.005),淋巴结采样站数及采样总数大于S^(2)b+S^(3)a组(P<0.001)。S^(2)b+S^(3)a组的第1天引流量、总引流量及引流管留置时间均小于右上叶组。两组均无围术期死亡,随访终点无复发及死亡。结论:在合理规划下,S^(2)b+S^(3)a联合亚段切除术是治疗右上肺S;和S^(3)之间早期低度恶性非小细胞肺癌等肺结节的一种安全可行的方式。

Role of 3DCT in laparoscopic total gastrectomy with spleen-preserving splenic lymph node dissection

AIM: To investigate whether computed tomography with 3D imaging (3DCT) can reduce the risks associated with laparoscopic surgery.

320排宽体探测器CT与3D-TEE对主动脉夹层患者分型诊断价值研究

目的:探讨320排宽体探测器CT与三维经食道超声心动图(3D-TEE)对主动脉夹层(AD)患者分型诊断的价值。方法:采集在医院就诊的28例患有主动脉夹层患者的临床资料,以手术治疗结果为金标准,对比CT与3D-TEE对患者AD类型诊断的符合率、准确率、灵敏度和特异度,以及AD患者的冠状动脉和主动脉根部的累及情况,采用DeBakey分型分析CT与3D-TEE对AD患者的诊断价值。结果:CT血管造影(CTA)诊断的灵敏度、特异度和准确率分别为92.9%、17.9%和96.4%,3D-TEE分别为71.4%、42.8%和78.6%,其差异有统计学意义(x^(2)=4.383,x^(2)=4.139,x^(2)=4.082;P<0.05);3D-TEE对夹层分型中近端与远端型、近端型和远端型3种类型的诊断符合率均为100%,CTA检测DeBakey分型中对夹层分型Ⅰ型、Ⅱ型和Ⅲ型的诊断符合率分别为69.2%、87.5%和100%,CTA对夹层分型总诊断率为82.1%,低于3D-TEE对夹层分型(100%),差异有统计学意义(x^(2)=5.490,P<0.05);CTA检测冠状动脉累及率为44.4%,3D-TEE检测为88.9%,差异有统计学意义(x^(2)=4.571,P<0.05);CTA检测主动脉根部累及率为62.5%,3D-TEE检测为93.8%,差异有统计学意义(x^(2)=4.571,P<0.05)。结论:实时3D-TEE能够准确诊断AD的类型,破口的位置及冠状动脉和主动脉根部的累及情况,对解剖位置的选择有着重大作用。

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.

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

正常脑血管的螺旋CT血管造影及三维重建技术

目的押对正常头颅螺旋CT血管造影穴spiralCTangiography熏SCTA雪表现及三维重建穴three-dimensionalreconstruction,3D雪进行探讨。材料与方法押24例中,男14例,女10例,年龄11～43岁,平均年龄26.7岁。采用Picker螺旋CT扫描仪进行SCTA,螺距穴pitch雪1.0～1.5,扫描层厚1.0mm。图像后处理,均采用为血管成像最大强度投影法穴maximumintensityprojection,MIP雪和表面遮盖显示法(surfaceshadeddisplay,SSD)并采取多个角度分析。结果押24例头颅脑血管MIP图像中颅底动脉环血管显示良好,均能显示脑血管1～4级结构。结论:SCTA是非创伤性血管检查方法,具有安全、简便、快捷、经济的优点。

应用于医学三维影像的血管结构自动提取

针对从计算机断层扫描血管造影术(CTA)的三维体数据中提取血管结构信息通常需要大量的人为介入操作的问题,提出了一种全自动血管分割方法。首先,采用多尺度增强滤波器对数据中的管状结构进行增强,剔除非管状结构,并过滤噪声。然后,利用Sigmoid函数作用于梯度图像产生水平集的速度图像,并通过测地活动轮廓模型迭代逼近真实的三维血管轮廓。最后,通过拉普拉斯算法对提取的血管表面网格进行平滑处理,获得光滑的血管曲面。实验采用胸部和颈部的CTA体数据对算法进行测试,结果表明:该方法无需人工干预即可从CTA体数据中准确地提取出血管的三维信息;血管中心线提取的平均误差为0.26mm,直径测量平均误差为0.16mm,分割精度满足临床血管疾病辅助诊疗的要求。

Research on CT characteristics reconstruction technology

The traditional computed tomography(CT)reconstruction methods are noisy,low resolution,poor contrast,and generally not suitable to detect the smaller flaws.Besides,the filter design is also difficult.The CT characteristics reconstruction technology was brought forward to improve in these aspects,which is defined to directly reconstruct the characteristics of the projection for the best requirements not the overall image quality.The two-dimension(2D)and three-dimension(3D)CT characteristics reconstruction algorithm were firstly introduced,then by detailed analysis,experimental results and comparsion of parameters calculated,its advantages in keeping better high-frequency feature,better noise immunity,short time-consuming and easier design are verified.