Improvement of Efficiency and Flexibility in Multi-slice Helical CT

One of the main aspects in computed tomography (CT) development is to make CT rapidly scan a large longitudinal volume with high z-axis resolution. The combination of helical scanning with multi-slice CT is a promising approach. Image reconstruction in multi-slice CT becomes, therefore, the major challenge. Known algorithms need to derive the complementary data or work only for certain range of pitches. A reconstruction algorithm was presented that works with the direct data as well as arbitrary pitches. Filter interpolation based on the proposed method was implemented easy. The results of computer simulations under kinds of conditions for four-slice CT were presented. The proposed method can obtain higher efficiency than the conventional method.

Analysis of The Value of Multi-Slice Spiral CT and Magnetic Resonance Imaging in The Diagnosis of Carpal Joint Injury

Objective:To analyze the value of multi-slice spiral computed tomography(CT)and magnetic resonance imaging(MRI)in the diagnosis of carpal joint injury.Methods:A total of 130 patients with suspected wrist injuries admitted to the Department of Orthopedics of our hospital from January 2023 to January 2024 were selected and randomly divided into a single group(n=65)and a joint group(n=65).The single group was diagnosed using multi-slice spiral CT,and the joint group was diagnosed using multi-slice spiral CT and magnetic resonance imaging,with pathological diagnosis as the gold standard.The diagnostic results of both groups were compared to the gold standard,and the diagnostic energy efficiency of both groups was compared.Results:The diagnostic results of the single group compared with the gold standard were significant(P<0.05).The diagnostic results of the joint group compared with the gold standard were not significant(P>0.05).The sensitivity and accuracy of diagnosis in the joint group were significantly higher than that in the single group(P<0.05).The specificity of diagnosis in the joint group was higher as compared to that in the single group(P>0.05).Conclusion:The combination of multi-slice spiral CT and MRI was highly accurate in diagnosing wrist injuries,and the misdiagnosis rate and leakage rate were relatively low.Hence,this diagnostic program is recommended to be popularized.

Three-dimensional Imaging of Multi-slice Spiral CT in Bronchial Artery Correlative Study on Blood Supply of Central Lung Cancer and Its Clinical Significance

Objective: To evaluate three-dimensional bronchial artery imaging charactersin central lung cancer and applied values with multi-slice spiral CT (MSCT) to provide theoreticalevidence on blood supply and intervention therapy. Methods: Eighteen patients with central lungcancer underwent MSCT with real time helical thin-slice CT scanning. Three-dimensional bronchialartery reconstruction was done at the console work-station. The space anatomical characters ofbronchial artery were observed through different rotations. Results: For 6 cases, thethree-dimensional images of bronchial artery (33.33%) could exactly show the origins, the routes(lung inner segment and mediatism segment) and the diameters of bronchial arteries. Vision rate ofbronchial arteries was the highest in pulmonary artery stricture and truncation groups, and thevessels' diameter became larger apparently. These characters demonstrated blood supply of this kindof central lung cancer come from bronchial artery. Volume rendering images were the best ones amongthree-dimensional images. Conclusion: Three-dimensional imaging with MSCT in bronchial artery canreveal the anatomical characters of bronchial artery and provide theoretical evidence on bloodsupply and intervention therapy of central lung cancer.

Multi-slice Spiral CT Three-dimensional Portography in Portal Vein Tumor Thrombus of Hepatic Cancer

Objective: To study the clinical significance of multi-slice spiral CT 3-dimensional (3D) portography in portal vein tumor thrombosis of hepatocellular cacinoma.Methods: 57 cases undergoing 3D portography were collected, of which 6 cases were normal, 5 cases were subjected to cirrhosis and hypertension of portal vein, 42 cases had portal tumor thrombus of hepatic cancer, and the remaining 4 cases showed lymph node enlargment in hilar of liver. All data of the patients came from conventional multi-slice spiral CT double phase of liver. Contrast media was 1.5–2 ml/kg with the injection rate being 2.5–3 ml/s. Axis and 3D portography was analyzed and compared in 42 cases of portal tumor thrombus of hepatic cancer.Results: According to portal tumor thrombus position, 42 cases were fallen into three categories: left (13 cases), right (20 cases), main (9 cases) of potal vein. There was no difference between axis and 3D portography in displaying portal tumor thrombus of hepatic cancer (P>0.05), but 3D portography showing collateral branches was better than axis portography after main portal vein thrombus.Conclusion: Multi-slice spiral CT 3D portography can display the position and types of portal tumor thrombus of hepatic cancer. 3D combined with axis portography can better evaluate the portal tumor thrombus of hepatic cancer and guide to select the therapies. Key words portal vein - tumor thrombus - multi-slice CT - 3 dimension imaging

Multi-slice spiral CT angiography in evaluating donors of living-related liver transplantation

BACKGROUND: During the past years, the number of liver transplantation has increased greatly, but the number of available organs has not increased. In view of the critical shortage of organs, the indications for living-related liver transplantation (LRLT) have broadened since experience with the procedure has been achieved. This study was undertaken to assess the value of multi-slice spiral CT (MSCT) angiography in evaluating the hepatic arterial and veinous anatomy of potential donors for LRLT. METHODS: MSCT was performed after intravenous injection of contrast material at 3 ml/s. The total dose was calculated as 2 ml/kg. Twenty LRLT donors (2 men and 18 women) were subjected to MSCT angiography of hepatic blood vessels. These were generated by volume rendering and maximum intensity projection, while curved planar reformation was added in 5 patients. RESULTS: We identified 10 important hepatic vascular variants in 9 of the 20 donors (4 arterial, 4 venous, and 2 portal venous variants). In hepatic arterial variants, two had a replaced right hepatic artery arising from the superior mesenteric artery, an accessory right hepatic artery from the superior mesenteric artery and a replaced left hepatic artery arising from the left gastric artery. In hepatic venous variants, three had an accessory inferior right hepatic vein and one had two accessory inferior right hepatic veins. In hepatic portal venous variants, two had trifurcation of the main portal vein. CONCLUSIONS: As a non-invasive and reliable method, MSCT angiography is of value in the clinical evaluation of LRLT donors. MSCT angiography should be recommended as a routine preoperative examination for potential LRLT donors.

Application of two-phase helical CT in liver neoplasms

Objective: To assess the value of helical CT in the di- agnosis of liver diseases. Methods: 59 patients with different liver diseases were examined by two-phase or multi-phase dynamic helical CT. Results: Small hepatocellular carcinoma showed a higher density in the arterial phase, and a lower den- sity in the portal vein phase. Large hepatic carcino- ma showed a mixed pattern of higher-density in the arterial phase, and a lower density in the portal vein phase. Metastasis carcinoma showed an 'oxeye sign' in the portal vein phase. Hemangioma was not obvi- ously enhanced in the early arterial phase, marginal- ly enhanced in the arterial phase, and equally-densed in the balanced phase. Conclusion: Two-phase helical CT is of value in im- proving the detection rate of or determining the fea- tures of hepatic diseases by two-phase helical dyna- mic scan (2.0-3.0 ml/s speed, and delay time 25- 30 s and 70-85 s).

Study on the combined value of multi-slice spiral CT in the diagnosis of elderly colorectal cancer colorectal cancer tumor markers

Objective:To investigate the value of tumor markers in colorectal cancer with multi-slice spiral CT in the diagnosis of elderly colorectal cancer.Methods:From January 2016 to September 2017 year period, 73 elderly patients with colorectal cancer treated in our hospital were selected as observation group;64 elderly patients with intestinal benign lesions were selected as control group during the same period. Serum samples were collected to detect contents of CEA, CA72-4, CA19-9 and CYFRA21-1 by Roche luminous immunoassay analyzer, and multi slice spiral CT was used.Results:Serum levels of CEA, CA72-4, CA19-9 and CYFRA21-1 levels of the observation group were significantly higher than that of the control group;the positive rate of CEA, CA72-4, CA19-9, CYFRA21-1 and their combined detection were all significantly higher than that of the control group;positive rate of MSCT in the observation group was higher than the control group;positive rates of tumor markers combining with MSCT examination of colorectal cancer were higher than that of combined detection of tumor markers and MSCT examination;but there was no significant difference in positive rate of combined detection of tumor markers and the positive rate of MSCT detection of colorectal cancer.Conclusion:Colorectal cancer tumor markers combined with multi-slice spiral CT in the diagnosis of colorectal cancer in elderly has important research value, can significantly improve the positive rate of diagnosis.

Establishing models of portal vein occlusion and evaluating value of multi-slice CT in hepatic VX2 tumor in rabbits

AIM： To establish models of portal vein occlusion of hepatic VX2 tumor in rabbits and to evaluate the value of multi-slice CT. METHODS： Forty New Zealand rabbits were divided into 4 groups according to digital table： Immediate group （group A; transplantation of tumor immediately after the portal vein occlusion）, 3-wk group （group B; transplantation of tumor at 3 wk after the portal vein occlusion）, negative control group （group C） and positive control group （group D）, 10 rabbits in each group. Hepatic VX2 tumor was transplanted with abdominalembedding innoculation immediately after the portal vein occlusion and at 3 wk after the portal vein occlusion. Meanwhile, they were divided into negative control group （Left external branch of portal vein was occluded by sham-operation, and left exite was embedded and inoculated pseudoly） and positive control group （Transplanted tumor did not suffer from the portal vein occlusion）. All rabbits were scanned with multi-slice CT. RESULTS： All 40 animals were employed in the final analysis without death. Tumor did not grow in both immediate group and 3-wk group. In 3-wk group, left endite was atrophied and growth of tumor was inhibited. The maximal diameter of tumor was significantly smaller than that in positive control group （2.55±0.46 vs 3.59±0.37 cm, t = 5.57, P 〈 0.001）. Incidences of metastasis in the liver and lung were lower in 3-wk group than those in positive control group （10% vs 400, and 90% vs 100%, respectively）. The expression intensities of the vascular endothelium growth factor （VEGF） in groups A, B, C and D were 0.10±0.06, 0.66±0.21, 0.28±0.09 and 1.48±0.32, respectively. VEGF expression level in the test group A was significantly lower than that in the negative control group C （t = 5.07; P 〈 0.001）.In addition, VEGF expression in the test group B was significantly lower than that in the positive control group D （t = 6.38; P 〈 0.001）. Scanning with multi-slice CT showed that displaying rate of hepatic artery branches was obviously lower in grade Ⅲ（40%） than that in grade Ⅰ（70%） and Ⅱ（100%） （P 〈 0.05）; but there was no significant difference in displaying rate of the portal vein at various grades. Values of blood flow （BF） of the liver, blood volume （BV）, mean transit time （MTT） and permeability of vascular surface （PS） were lower in the immediate group and 3-wk group than those in control groups, but values of hepatic arterial fraction （HAF） were increased. Significant positive correlations were existed between BF and BV （r = 0.905, P 〈 0.01）, and between BF and PS （r = 0.967, P 〈 0.01）, between BV and PS （r = 0.889, P 〈 0.01）. A significant negative correlation existed between PV and HAF （r = -0.768, P 〈 0.01）, between PS and HAF （r = -0.557, P 〈 0.01）. The values of BF, BV and PS had a positive correlation with VEGF （rBF = 0.842, rBV = 0.579, rPS = 0.811, P 〈 0.01） . However, there was no significant correlation between the values of MTT and HAF and the VEGF expression （rMTt = 0.066, rHAF = -0.027）. CONCLUSION： Ligating the left external branch of portal vein is an ideal way to establish models of portal vein occlusion in rabbits with hepatic VX2 tumor. Multi slice CT plays a key role in evaluating effect of portal vein occlusion.

Value of Multi-slice Spiral CT in the Diagnosis and Resectability of Pancreatic Cancer

Objective:To analyze the value of multislice spiral CT in the diagnosis and resectability of pancreatic cancer.Method:56 patients with pancreatic cancer treated in our hospital from January 2018 to October 2019 were selected as the research subjects.All patients underwent multi-phase scanning by multislice spiral CT.According to the results of the images,observe whether the pancreatic cancer has affected the blood vessels surrounding the pancreas,evaluate the resectability based on the results of the examination,and analyze the final results of the operation which was taken as the standard.Results:all the 56 cases presented slightly low density or equal density,and 28 cases had complete outline.Multi-slice spiral assessment of patients’vascular invasion types found that 192 branches can be resected with 70 branches cannot;Multi-slice spiral assessment of the main arterial and venous invasion grades around the pancreas of the patients found that 212 branches can be resected with 50 branches cannot;Multi-slice spiral CT was used to evaluate the resectability of pancreatic cancer compared with surgical results.The accuracy of resectable types of vascular invasion was 72.52%;the accuracy of resectable vascular invasion grades was 79.39%.Conclusion:the application of multi-slice spiral CT in the diagnosis of pancreatic cancer can provide a clear understanding of the condition of vascular invasion and distant metastasis,and the accuracy of assessing resection can reach more than 70.00%,which provides a reference for clinical application.

Derivative-Hilbert-Backprojection based image reconstruction from truncated projections in helical cone-beam CT

In helical cone-beam computed tomography(CT), Feldkamp-Davis-Kress(FDK) based image reconstruction algorithms are by far the most popular. However, artifacts are commonly met in the presence of lateral projection truncation. The reason is that the ramp filter is global. To restrain the truncation artifacts, an approximate reconstruction formula is proposed based on the Derivative-Hilbert-Backprojection(DHB) framework. In the method, the first order derivative filter is followed by the Hilbert transform. Since the filtered projection values are almost zero by the first order derivative filter, the following Hilbert transform has little influence on the projection values, even though the projections are laterally truncated. The proposed method has two main advantages. First, it has comparable computational efficiency and image quality as well as the conventional helical FDK algorithm for non-truncated projections. The second advantage is that images can be reconstructed with acceptable quality and much lower computational cost in comparison to the Laplace operator based algorithm in cases with truncated projections. To point out the advantages of our method, simulations on the computer and real data experiments on our laboratory industrial cone-beam CT are conducted. The simulated and experimental results demonstrate that the method is feasible for image reconstruction in the case of projection truncation.

Comparison of the Imaging Manifestations and Diagnostic Values of Multi-slice Spiral CT and Enhanced MRI Scans of Primary Liver Cancer(PLC)Intrahepatic Lesions

Objective:To compare and analyze the clinical diagnostic value of multi-slice spiral CT and enhanced MRI for primary liver cancer(PLC),and to summarize the imaging findings.Methods:The research subjects in this article were 50 patients with PLC who were admitted to our hospital from 2017 April to 2018 September.After the patients were admitted,they were examined by multi-slice spiral CT and enhanced MRI scanning,and the pathological diagnosis results were followed up.Relevant information was reviewed and analyzed.Results:The detection rate of multi-slice spiral CT was higher than that of MRI in the portal venous phase lesion detection.The difference was statistically significant(P<0.05).The detection rate of lesions in the arterial phase and delayed phase was not statistically significant(P>0.05);the diagnostic accuracy of multi-slice spiral CT was 85.96%,and the diagnostic accuracy of enhanced MRI scanning was 91.11%,which was not statistically significant(P>0.05).MRI scans showed the capsules of primary liver cancer better than CT,but the difference was not statistically significant(P>0.05).Conclusion:In conclusion,both multi-slice spiral CT and enhanced MRI can be used for the effective diagnosis of primary liver cancer intrahepatic lesions.The diagnostic value of the two is equivalent,but enhanced MRI has a slightly higher diagnostic accuracy and can be used as the preferred method.

Value of helical CT volume rendering technique in post-operative evaluation of screw in screw fixation of axis fractures

To explore the value of helical CT volume rendering technique (VRT) in post-operative evaluation of screw fixation of axis fractures.Methods There were 21 cases of screw fixation of axis fractures between February 2002 and May 2004 in the study including six cases with fractures on axis body,five on odontoid process and 10 on axis body and odontoid process.All cases received X-ray plain film,helical CT scanning,multi-planar reformatting(MPR) and VRT.Results Screw fixation through axis body and massa lateralis atlantis was performed in 10 cases and that through axis body and odontoid process in 11.VRT could clearly display full aperture of screw orbit,location of screw and angle of fixation and hence was superior to X-ray plain film and MPR.Multi-angle VRT displayed asymmetrical space of odontoid process and massa lateralis atlantis in four cases and medial deviation of 2～5 mm of half screw in screw fixation through axis body and massa lateralis atlantis in six.Conclusion VRT can eliminate false shadow of fixation screw,clearly display full aperture of screw orbit and hence supply improtant imaging evidence for post-operative evaluation of screw fixation of axis fractures.7 refs,1 fig,1 tab.

14例Abernethy畸形患者多层螺旋CT及MRI影像学表现分析

目的分析Abernethy畸形患者多层螺旋CT(multislice helical CT,MSCT)及MRI影像资料,以提高对该类疾病的认识。方法选取2015年1月至2022年1月中山大学附属第一医院及韶州人民医院符合诊断标准的l4例具有完整MSCT或MRI影像资料的Abernethy畸形患者作为研究对象,分析其影像学表现。结果14例患者中,4例Ⅰ型Abernethy畸形患者影像学表现为肝门静脉缺如,1例Ⅰa型门静脉缺如脾静脉-左肾静脉,肠系膜上静脉-腔静脉,3例Ⅰb型Abernethy畸形患者中,肠系膜上静脉及脾静脉-左肾静脉2例,门脉缺如,肠系膜上静脉及脾静脉-腔静脉;肝动脉增粗1例;10例Ⅱ型Abernethy畸形患者影像学特点为门静脉主干或分支细小,部分分支缺如,其中肠系膜上静脉及脾静脉-左肾静脉7例,肠系膜上静脉及脾静脉汇入肠系膜下静脉再分支并与双侧髂内静脉沟通1例,门脉右支-腔静脉2例。结论Abernethy畸形是较罕见的先天性疾病,MSCT及MRI增强扫描是诊断本病的主要影像学手段,对疾病的分型及确定门体分流途径起到重要作用,提高对该病的认识是实现准确诊断的关键。

多层螺旋CT及其后处理技术对隐匿性骨折的诊断价值

目的 探讨多层螺旋CT(MSCT)二维(MPR、MIP)和三维(VRT、SSD)重建技术对复杂结构的隐匿性骨折的诊断价值。资料与方法 对4 2例外伤患者普通X线平片中未显示而临床怀疑有骨折的患者进行MSCT扫描后,通过特殊的CT图像处理软件包在工作站上进行后处理(MPR、MIP、VRT及SSD) ,得到外伤部位骨骼高清晰度的二维和三维图像后,由两位有经验的放射科医师共同阅片,以共同意见为准。结果 4 2例X线平片中未显示骨折的患者经MSCT重建后,18例显示有骨折,其中枕骨骨折2例,肩胛骨骨折2例,肋骨骨折4例,脊椎骨折3例,骨盆骨折3例,股骨颈骨折3例,跟骨骨折1例。结论 MSCT二维和三维重建对临床怀疑骨折而普通X线不能确诊为骨折的病例能准确地作出诊断,并对治疗方案的选择及预后的估计有重要价值。

胆管癌螺旋CT强化特征与病理学对照研究

目的 探讨胆管癌的螺旋CT增强扫描表现与病理学的关系 ,以及螺旋CT的诊断价值。资料与方法 2 8例经手术及病理证实的肝门区胆管癌的螺旋CT平扫及多期增强扫描资料 ,重点观察肿块相对于肝脏的密度变化。结果 肝门区胆管癌CT主要表现为肝门区不规则低或略低密度软组织肿块 ,在动态扫描过程中相对于肝脏密度的变化趋势为高、低、高。 75 % (2 1/ 2 8)的病变于门脉期 (10例 )和延迟期 (11例 )显示最清楚 ,19例有延迟强化 ,延迟强化率为 6 7.9% (19/ 2 8) ;此外螺旋CT还清楚地显示了胆管扩张 ,肝叶萎缩 ,病变周围的异常强化区等间接征象。结论 肝门区胆管癌的CT表现与病理密切相关 。

急性阑尾炎的CT表现

目的 探讨急性阑尾炎的CT表现。方法 对 68例手术、病理证实为急性阑尾炎病人的腹部CT资料进行回顾性分析 ,对阑尾大小、有无阑尾结石、阑尾周围及盲肠末端的改变作了观察、分析。结果 68例中 61例CT诊断为急性阑尾炎 ,7例假阴性 ,CT诊断急性阑尾炎的敏感性为 89.7%。急性阑尾炎的CT表现主要有阑尾增粗 ( 76.5 % ) ,阑尾结石( 2 9.4% ) ,阑尾周围炎性改变 ( 66.2 % ) ,阑尾脓肿 ( 13 .2 % ) ,蜂窝织炎 ( 10 .3 % ) ,盲肠末端肠壁增厚 ( 7.4% )和局部淋巴结肿大 ( 5 .9% )。结论 急性阑尾炎可出现多种CT表现 ,熟悉这些表现有助于提高CT诊断阑尾炎的准确性。

螺旋CT对胃癌浸润及转移的诊断价值

目的 评价螺旋CT三期增强扫描对胃癌浸润及转移的准确性,并探讨影像学与病理学的内在联系。资料与方法 对46例胃癌患者行螺旋CT三期增强扫描并与术后病理对照。结果 (1)螺旋CT诊断浆膜受侵、淋巴结转移和远处转移的准确性分别为84.8％、87.0％和100％。(2)螺旋CT征象中浆膜侵犯、淋巴结转移和远处转移均与其病理特征密切相关(P<0.05)。结论 螺旋CT三期增强扫描能较全面、准确地反映胃癌病理特征,是诊断胃癌浸润及转移的可靠影像学方法。

非增强螺旋CT扫描对急性阑尾炎的诊断价值

目的 评价非增强螺旋CT扫描对急性阑尾炎的诊断价值。资料与方法 对 115例临床怀疑急性阑尾炎患者作非增强螺旋CT扫描 ,不口服或结肠内灌注对比剂 ,层厚 10mm ,Pitch 1,扫描范围从L3 椎体至耻骨联合。CT诊断急性阑尾炎的标准包括阑尾增粗横径超过 6mm ,或阑尾结石同时伴有阑尾周围的炎性改变。CT诊断结果与手术、病理或临床随访结果进行对照。结果 CT发现 5 6例真阳性 ,49例真阴性 ,7例假阴性和 3例假阳性。CT诊断急性阑尾炎的敏感性为 89%,特异性为 94%,准确性为 91%,阳性预测值为 95 %,阴性预测值为 88%。 49例无阑尾炎患者中 ,CT发现其他病变 2 2例 (45 %)。结论 非增强螺旋CT扫描 ,能快速、准确地诊断有无急性阑尾炎 ,而且还能发现除阑尾炎以外的其他各种病变。

实时灰阶超声造影和螺旋CT诊断肝肿瘤的比较研究

目的 比较实时超声造影和螺旋CT显示肝肿瘤血流信号的特点。方法 对 2 9例肝肿瘤 (原发性肝癌 16例 ,转移性肝癌 2例 ,血管瘤 6例和肝局灶性结节增生 5例 )分别进行超声造影和CT检查。结果 超声造影显示肝恶性肿瘤的整体型、血管瘤的周边型及局灶性结节增生的中央型出现率显著高于其他病变 (P <0 .0 1)。CT示恶性肿瘤中 94.4%( 17/ 18)动脉期强化、门脉期低密度 ;血管瘤中 83 .3 % ( 5 / 6)呈结节状强化 ;肝局灶性结节增生动脉期均明显强化。超声造影和CT鉴别肝肿瘤的能力无显著差异。结论 超声造影和CT都能敏感地显示不同肝肿瘤的血供特征。

周围性肺栓塞螺旋CT强化扫描肺密度测量的研究

目的 探讨螺旋CT平扫与强化扫描肺实质密度测量在周围性肺栓塞诊断中的作用。方法 8只犬于DSA下复制为单侧周围性肺栓塞动物模型后进行螺旋CT平扫和强化扫描 ,根据DSA发现的栓塞肺动脉的位置 ,于螺旋CT平扫和强化扫描图像上分别测量栓塞区与对侧肺正常肺实质的CT值 ,比较双肺的CT值差异与净增CT值差异。结果 螺旋CT平扫栓塞区的CT值与对侧正常肺实质的CT值之间无明显差异 (P >0 .0 5 ) ;螺旋CT强化扫描显示栓塞区的CT值明显低于正常肺实质的CT值 (P <0 .0 1) ,而且栓塞区的净增CT值也明显低于正常肺实质的净增CT值 (P <0 .0 1)。结论 螺旋CT强化扫描可以发现周围性肺栓塞所致的低灌注区 。