64层螺旋CT冠状动脉成像评价冠状动脉钙化与狭窄的临床应用研究

目的探讨64层螺旋CT冠状动脉成像评价冠状动脉钙化和狭窄的临床应用价值。方法对32例临床确诊或疑诊冠状动脉粥样硬化性心脏病患者行64层螺旋CT冠状动脉成像。利用平扫图像进行钙化积分测量,冠状动脉CTA扫描后进行多平面重建（MPR）、曲面重建（CPR）及容积再现（VRT）,其中,9例行常规冠状动脉造影作对照,总结CTA的评价方法和显示情况,分析影响冠状动脉成像质量的因素。结果64层螺旋CT平扫能测定钙化积分,而MPR、CPR及VRT能多角度显示冠状动脉主干及主要分支,MPR与CPR对显示冠状动脉病变优于VRT。本组患者中,冠状动脉管壁欠光滑见于10例,管壁钙化11例,非钙化斑块15例,管腔狭窄18例。影响图像质量的因素主要是心率、心律及呼吸运动。结论64层螺旋CT冠状动脉成像是一种安全、快速、无创的诊断冠状动脉粥样硬化性心脏病的方法,也可作为筛查公众中冠状动脉病变的重要手段。     

64层螺旋CT成像技术对下肢动脉病变显示的探讨

目的:探讨64层螺旋CT血管成像技术的不同后处理方法对下肢动脉病变的显示。方法:采用4种不同的后处理方法(MPR、MIP、VRT、CTVE)针对其下肢动脉疾病中常见病变:血管狭窄、管壁钙化、管腔内软斑块、侧支循环进行扫描。结果:MPR对血管狭窄、管壁钙化、管腔内软斑块、侧支循环的显示情况按显示率依次为95.7%、91.1%、95.4%、23.2%;VRT显示率依次为84.9%、88.4%、0%、85.7%;MIP显示率依次为87.1%、97.3%、20.7%、94.7%;CTVE显示率依次为19.4%、0%、0%、0%。结论:MPR对血管腔内软斑块、血管狭窄显示优于其他方法;MIP及VRT显示钙化灶及侧支循环有优势;CTVE可以显示血管腔内狭窄及闭塞,可作为其他方法的补充。     

电子束CT血管三维重建技术与冠状动脉成像

目的　分析电子束CT(EBT)三维血管重建技术对冠状动脉及其狭窄的最佳显示方法。方法　对 40例分别行EBT冠状动脉增强扫描及常规冠状动脉造影 (CAG)的病例图像行回顾性三维重建。重建方法主要是最大密度投影法 (MIP)、曲面重建法(CPR)、多平面重组法 (MPR)及容积再现法 (VR)。所有三维重建图像由 2名不知CAG结果的医师按左主干、前降支、回旋支及右冠4支血管进行分析 (分支血管未包括在内 ) ,狭窄程度以 >5 0 %为标准与CAG结果对照。结果　MIP及CPR成像清晰 ,对 48支正常冠状动脉的评价准确率达 91.7%和 93 .8% ,对 5 9支狭窄 >5 0 %血管的评价准确率分别为 83 .1%和 88.1%。VR法重建立体效果好 ,但图像易造成正常血管狭窄的假象 ,48支正常血管中有 2 9支显示狭窄改变。对有狭窄血管的程度也较CAG夸大了约 10 %～3 0 %。MPR重建图像粗糙 ,无法评价冠状动脉。结论　MIP与CPR是显示冠状动脉及其狭窄的最佳三维重建方法 ,诊断准确性高 ,VR可作为补充显示方法 ,MPR可不采用     

64排CT冠状动脉成像多种后处理技术在冠状动脉狭窄的对比研究

目的 探讨64排冠状动脉CTA各种图像后处理技术在诊断引起血流动力学变化的冠状动脉狭窄的意义.方法 101例患者进行冠状动脉CTA检查.4个研究者分别对影像资料进行分析,评估各冠状动脉的图像质量,使用横断位图像、多斜面重建(MPR)、最大密度投影(MIP)、曲面MPR、曲面MIP、三维立体容积再现重建(VRT)分别对各冠状动脉节段进行分析,所得结果与DSA冠状动脉造影结果对比.结果 64排冠状动脉CTA图像共显示95条冠状动脉狭窄,可评估的冠状动脉节段数及能精确探测冠状动脉狭窄的百分数分别是:横断位为99%和92%,斜MPR为99%和93%,斜MIP为96%和89%,曲面 MIP为96%和87%,曲面 MPR为95%和81%,VRT为88%和75%.探测冠状动脉狭窄的精确性斜MPR、斜MIP(P＜0.05)、曲 面MPR(P＜0.005)、曲面MIP(P＜0.05) 及VRT(P＜0.005)五者相比较而言,斜MPR的精确性最高.结论 64排CT冠状动脉各节段CTA图像质量能满足诊断要求.以横断位为基础,利用多种后处理方法可以评价冠状动脉狭窄,特别是斜MPR能够比较精确诊断冠状动脉狭窄.     

16层螺旋CT冠状动脉成像的临床应用

目的 探讨16层螺旋CT冠状动脉造影的临床应用价值及影响成像质量的因素.方法 对31例临床怀疑冠心病患者行16层螺旋CT扫描,利用回顾性心电门控技术,行普通扫描(层厚3 mm)和冠状动脉成像扫描(层厚1 mm),并进行多平面重建(MPR)、最大密度投影重建(MIP) 、容积重建(VRT),评价16层螺旋CT对各支冠状动脉的显示能力、病变的检出率,总结部分影响冠状动脉成像的因素.结果 16层螺旋CT对RCA1、RCA2、LAD1、LAD2、LM、LCX1的显示良好.心律、呼吸运动、管壁大量钙化等因素均可影响成像质量.结论 16层螺旋CT冠状动脉成像在冠状动脉疾病的筛选及诊断中具有一定的应用价值.     

16排40层螺旋CT冠状动脉血管造影的应用技术探讨简

目的：探讨16排40层螺旋CT冠状动脉血管造影的应用技术。方法使用东芝公司16排螺旋CT进行冠状动脉血管成像检查,采用多平面重建（MPR）、最大密度投影（MIP）、曲面重建（CPR）和容积再现技术（VR）进行图像后处理,可清晰显示冠状动脉主干及主要分支。结果心率平稳为53~66次/min,冠状动脉节段图像质量可准确地显示冠状动脉通畅情况及管壁病变。心率＞68次/min时,冠状动脉的主要分支显示不规整。结论16排CT冠状动脉成像可比较准确诊断冠状动脉病变,具有较高的临床应用价值。     

螺旋CT诊断原发性输尿管癌的价值

目的:探讨原发性输尿管癌螺旋CT扫描及三维重建的影像特点和诊断价值.材料和方法:回顾性分析14例经手术病理证实原发性输尿管癌的螺旋CT影像表现,分析其特点.14例患者中13例行增强扫描,1例为逆行性尿路造影后CT平扫,14例均行MPR/CPR重建,4例同时行MIP重建及VE检查.结果:CT增强轴位扫描及MPR/CPR重建能够清晰地显示肿瘤的大小、形态、范围及其与周围组织的关系;MIP重建能很好地显示肿瘤引起的输尿管管腔不规则狭窄或截断改变;VE检查则能够从管腔内观察肿瘤的形态.结论:螺旋CT容积扫描及三维重建能够多平面、多方位、立体地显示病变,使病变定位、定性诊断更加准确,为临床手术治疗提供帮助.     

128层CT多种图像后处理技术评估心肌桥-壁冠状动脉

目的 探讨128层螺旋CT对心肌桥的诊断效能,评估壁冠动脉狭窄程度.方法 对146例可疑冠心病患者进行128层螺旋CT冠状动脉血管成像,VR、MIP、MPR、CPR对血管进行重建,短轴多平面重组,分析血管在收缩期或舒张期血管狭窄程度.结果 多种图像后处理技术中,MPR/CPR/MIP重建更有利于心肌桥一壁冠状动脉的显示;共检出30例心肌桥,34段;19例发生在前降支,10例发生在回旋支,1例发生在右冠状动脉;17例伴有不同程度的邻近冠状动脉粥样板块形成;1例合并冠状动脉起源异常.结论 128层螺旋CT结合多种图象后处理技术,尤其MPR/CPR/MIP重建可以清晰显示心肌桥一壁冠状动脉,是一种能够无创、准确诊断心肌桥一壁冠状动脉的重要手段.     

多层螺旋CT冠状动脉成像在冠心病中的临床应用

目的　评价多层螺旋CT冠状动脉造影 (MSCTA)在冠心病中的应用价值。方法　对4 0例冠心病患者 (35例拟诊冠心病 ,5例冠状动脉支架或搭桥术后患者 )进行了心电门控螺旋CT(MSCT)增强扫描 ,所得数据传到工作站进行三维重建 ,并与冠状动脉造影结果相对照。结果　 4 0例患者中对 16 0支冠状动脉 (简称冠脉 )进行了MSCT三维重建 ,35例拟诊者中 4例MSCTA和DSA排除了冠脉疾病 ;31例 12 4支冠脉中 ,MSCTA对于显示近中段≥ 5 0 %的狭窄有一定的准确性 (敏感性 81 8% ,特异性 90 1% ) ,不能显示轻度狭窄病变、远端或细小分支病变 ;可以发现并判断粥样硬化斑块的类型 ,显示斑块的形态及引起狭窄的程度。钙化斑块特别是钙化范围广者可引起管腔轻度狭窄 (冠状动脉腔径狭窄 <5 0 % ) ,非钙化斑块则引起较明显的狭窄 (冠状动脉腔径狭窄≥ 5 0 % )。 4例冠状动脉支架和 1例冠状动脉搭桥术后均可清晰显示支架和血管桥的位置及远端血流情况。结论MSCTA是有效可靠的冠心病诊断方法 ,对病变血管管腔狭窄、粥样硬化斑块的评价有一定的应用价值。它作为一种非创伤性检查方法 ,可替代DSA用于易碎软斑块的早期检查。     

16层螺旋CT在血管病变诊断中的临床应用

目的评价16层螺旋CT血管造影(16SCTA)及重建技术在血管病变诊断中的临床应用价值。方法100例血管病变行16SCTA,采用准直0.75 mm,层厚1 mm,间隔0.5 mm。重建应用多平面重建(MPR),最大密度投影(M IP)及容积显示技术(VRT)。结果100例血管病变中65例经手术病理或DSA证实。100例病变中,8例脑动脉瘤,2例脑动静脉畸形,6例肺动静脉畸形,9例肺动脉栓塞伴下肢深静脉血栓,4例肺隔离症,20例冠状动脉软斑块和/或钙化,12例主动脉瘤,3例肾动脉狭窄,2例肠系膜上动脉血栓,1例股动脉狭窄,33例软组织血管瘤。这3种重建技术均能显示病变的大小、形态及范围,对病变可进行任意角度重建和观察,VRT可立体地显示病变。MPR和M IP可显示血栓,M IP和VRT显示钙化。结论综合应用16层螺旋CT的各种重建技术,能够全面而清晰地显示血管病变,可取代DSA,为患者提供一种安全可靠的诊断手段,对临床治疗具有重要指导意义。     

Virtual nonenhanced abdominal dual-energy MDCT: Analysis of image characteristics

AIM:To evaluate abdominal and pelvic image characteristics and artifacts on virtual nonenhanced(VNE) images generated from contrast-enhanced dual-energy multidetector computed tomography(MDCT)studies.METHODS:Hadassah-Hebrew University Medical Institutional Review Board approval was obtained;22 patients underwent clinically-indicated abdominal and pelvic single-source dual-energy MDCT(Philips Healthcare,Cleveland,OH,USA),pre-and post-IV administration of Omnipaque 300 contrast(100 cc).Various solid and vascular structures were evaluated.VNE images were generated from the portal contrast-enhanced phase using probabilistic separation.Contrast-enhanced-,regular nonenhanced(RNE)-,and VNE images were evaluated with a total of 1494 density measurements.The ratio of iodine contrast deletion was calculated.Visualization of calcifications,urinary tract stones,and image artifacts in VNE images were assessed.RESULTS:VNE images were successfully generated in all patients.Significant portal-phase iodine contrast deletion was seen in the kidney(61.7%),adrenal gland(55.3%),iliac artery(55.0%),aorta(51.6%),and spleen(34.5%).Contrast deletion was also significant in the right atrium(RA)(51.5%)and portal vein(39.3%),but insignificant in the iliac vein and inferior vena cava(IVC).Average post contrast-to-VNE HU differences were significant(P<0.05)in the:RA-135.3(SD 121.8),aorta-114.1(SD 48.5),iliac artery-104.6(SD 53.7),kidney-30.3(SD 34.9),spleen-9.2(SD 8.8),and portal vein-7.7(SD 13.2).Average VNE-toRNE HU differences were significant in all organs but the prostate and subcutaneous fat:aorta 38.0(SD 9.3),RA 37.8(SD 16.1),portal vein 21.8(SD 12.0),IVC 12.2(SD 11.6),muscle 3.3(SD 4.9),liver 5.7(SD 6.4),spleen 22.3(SD 9.8),kidney 40.5(SD 6.8),and adrenal 20.7(SD 13.5).On VNE images,196/213 calcifications(92%)and 5/6 renal stones(84%)were visualized.Lytic-like artifacts in the vertebral bodies were seen in all studies.CONCLUSION:Iodine deletion in VNE images is most significant in arteries,and less significant in solid organs and veins.Most vascular and intra-abdominal organ calcifications are preserved.     

Visualisation of intracerebral haemorrhage with flat-detector CT compared to multislice CT: results in 44 cases

The aim of the study was to test the reliability of intracerebral haemorrhage (ICH) detection with C-arm-mounted flat-detector computed tomography (FD-CT) in the angio suite as compared to multislice CT (MSCT). In this study 44 patients with 45 ICH were included. All patients were investigated with MSCT and FD-CT during angiographic evaluation. As a control group we included 16 patients without ICH. In each haematoma we assessed volumetric data of the ICH and counted the numbers of ICH-positive slices. Using interobserver ratings, we additionally investigated the potential of FD-CT to serve as a diagnostic tool to detect ICH. In FD-CT three haematomas were not detected because of motion and beam-hardening artefacts in the region close to the skull base. The r value for the degree of interobserver agreement for the number of slices was 0.95 for MSCT and 0.94 for FD-CT. Measurements of the area and the calculated volume of the ICH showed high inter- and intraobserver agreement. Our results indicate that FD-CT is a helpful tool in the daily emergency management of ICH patients as detection of ICH was found to be nearly as reliable as in MSCT. Limitations of this technology are motion and beam-hardening artefacts that may mask small haematomas located in the posterior fossa or the skull base.     

Computed tomography of the bowel: A prospective comparison study between four techniques

Objectives

The major objective was to prospectively compare the grade of bowel distension obtained with four different computed tomography (CT) techniques dedicated for the examination of the small intestine (CT enteroclysis [CTE] and enterography [CTe]), of the colon (CT with water enema [CT-WE]), or both (CTe with water enema [CTe-WE]). The secondary objective was to assess patients’ tolerance toward each CT protocol.

Materials and methods

Recruitment was designed to obtain four groups of the same number of patients (30). Each group corresponded to a specific CT technique, for a total of 120 consecutive outpatients (65 male and 55 female, mean age 51.09 ± 13.36 years).CTE was performed after injection of methylcellulose through a nasojejunal tube, while in the CTe protocol a polyethylene glycol electrolyte solution was orally administered to patients prior to the CT acquisition. In the CT-WE protocol intraluminal contrast (water) was administered only by a rectal enema, while CTe-WE technique included both a rectal water enema and oral ingestion of neutral contrast material to obtain a simultaneous distension of small and large bowel.CT studies were reviewed in consensus by two gastrointestinal radiologists who performed a quantitative and qualitative analysis of bowel distension on a per segment basis. The presence and type of adverse effects were recorded.

Results

CTE provided the best distension of jejunal loops (median diameter 27 mm, range 17–32 mm) when compared to all the other techniques (p < 0.0001). The frequency of patients with an adequate distension of the terminal ileum was not significantly different among the four groups (p = 0.0608). At both quantitative and qualitative analysis CT-WE and CTe-WE determined a greater and more consistent luminal filling of the large intestine than that provided by both CTE and CTe (p < 0.0001 for all colonic segments). Adverse effects were more frequent in patients belonging to the CTE group (p < 0.0028).

Conclusions

CTE allows an optimal distension of jejunal loops, but it is the most uncomfortable CT protocol. When performing CT-WE, an adequate retrograde distension of the terminal ileum was provided in a particularly high percentage of patients. CTe-WE provides a simultaneous optimal distension of both small and large bowel.     

Gated blood-pool emission tomography: A new technique for the investigation of cardiac structure and function

ECG-gated single-photon emission-computed tomography of the intracardiac blood pool is a new technique that has not previously been widely applied. It involves the acqusition of ECG-gated images of the intracardiac blood pools labelled with sodium pertechnetate Tc 99m in 32 projections around the left-anterior hemithorax using a rotating gamma camera. From these images, tomographic sections are reconstructed orthogonal to the long axis of the left ventricle. The heart is therefore imaged three dimensionally, and more extensive information is obtained than in planar radionuclide ventriculography where imaging is usually restricted to only a single projection. Both structure and function can be studied, and the left-ventricular volume and ejection fraction, and wall motion are obtained. Of 50 patients studied, 7 cases are illustrated in order to show normal findings, examples of wall motion that were not shown by planar-contrast and radionuclide ventriculography, examples of the localisation of ventricular hypertrophy, and a comparison between blood-pool and ²⁰¹TI myocardial tomography.This work was supported by the Sir Jules Thorn Charitable Trust     

PET-CT在乳腺癌诊断中的应用价值

乳腺癌是当今大多数国家妇女最常见的恶性肿瘤.在过去的数十年中,正电子发射体层显像（PET）的应用极大地提高了乳腺肿瘤的临床诊治率.然而由于PET对肿瘤病灶缺乏准确的解剖定位而使18F-氟代脱氧葡萄糖（18F-FDG）PET临床应用的准确性受到限制.PET-CT的完美结合使对肿瘤的解剖定位和诊断的敏感性及特异性得到了明显的提高.本文着重介绍PET-CT在乳腺癌治疗后再分期、疗效观察、术前分期和放疗计划拟定中的应用价值.     

PET-CT在乳腺癌诊断中的应用价值

乳腺癌是当今大多数国家妇女最常见的恶性肿瘤。在过去的数十年中,正电子发射体层显像(PET)的应用极大地提高了乳腺肿瘤的临床诊治率。然而由于PET对肿瘤病灶缺乏准确的解剖定位而使18F-氟代脱氧葡萄糖(18F-FDG) PET临床应用的准确性受到限制。PET-CT的完美结合使对肿瘤的解剖定位和诊断的敏感性及特异性得到了明显的提高。本文着重介绍PET-CT在乳腺癌治疗后再分期、疗效观察、术前分期和放疗计划拟定中的应用价值。     

Spectral photon-counting CT in cardiovascular imaging

Photon-counting computed tomography (PCCT) is an emerging technology promising to substantially improve cardiovascular imaging. Recent engineering and manufacturing advances by several vendors are expected to imminently launch this new technology into clinical reality. Photon-counting detectors (PCDs) have multiple potential advantages over conventional energy integrating detectors (EIDs) such as the absence of electronic noise, multi-energy capability, and increased spatial resolution. These developments will have different timescales for implementation and will affect different clinical scopes. We describe the technical aspects of PCCT, explain the current developments, and finally discuss potential advantages of PCCT in cardiovascular imaging.     

PET/CT——功能与解剖结构的同机图像融合

PET/CT为近几年出现的一种新技术,将PET与CT安装在同一机架上,一次扫描可获得PET与CT的融合图像,对定位诊断肿瘤、指导肿瘤放疗计划、选择活检部位及监测疗效等具有重要价值,同时,CT提供了一种PET衰减校正的方法。本文简要介绍PET/CT的结构设计与性能、优势及目前尚存在的技术问题。     

^18F-FDG PET-CT结合HRCT诊断细支气管肺泡癌的价值

目的探讨^18F-FDG PET-CT结合HRCT诊断细支气管肺泡癌的价值。方法回顾分析经病理证实的24例细支气管肺泡癌患者的PET-CT及其HRCT图像资料。分别记录其形态学表现及放射性分布，同时测量其最大SUV值（SUVmax）。结果根据形态学表现分为3型：（1）孤立结节型（12例）：表现为密度略不均匀或并有磨玻璃样密度的单发结节，主要征象为分叶、短毛刺、支气管充气征、胸膜凹陷征、空泡征、晕征、血管集束征。SUVmax均值为3．78±1．54；（2）多发结节型（5例）：表现为两肺散在多发的结节，以中下肺叶为主，结节大小不一，小结节无放射性聚积，对于直径〉5mm的结节，SUVmax均值为3．46±1．32。（3）肺炎型（7例）：为一个或多个肺叶的实变。其内见充气支气管征或蜂窝征，放射性分布不均匀，部分病灶FDG摄取为阴性。结论^18F-FDG PET-CT结合HRCT在细支气管肺泡癌的诊断中具有重要的应用价值。诊断时要密切结合PET与HRCT图像，以最大限度地减少误诊。     

Performance of the new generation of whole-body PET/CT scanners: Discovery STE and Discovery VCT

Purpose The new GE Discovery STE and Discovery VCT respectively combine 16-slice and 64-slice CT with PET. The PET scanner has a new BGO detector block of 8×6 matrix (6.3×4.7×30 mm³). The aim of this study was to test the performance of the new scanner. Methods The PET performance evaluation was done using NEMA methodology. Owing to improved front-end electronics, the system was tested with different energy window and coincidence timing settings. Results Transaxial resolution FWHM for 2D(3D) mode at 1 cm offset from the centre of the field of view (R1) was 4.87 mm (5.12 mm) and at 10 cm off centre (R10) radially 5.70 mm (5.89 mm) and tangentially 5.84 mm (5.47 mm). The axial resolutions were 4.4 mm (5.18 mm) (R1) and 5.99 mm (5.86 mm) (R10). The sensitivities were 2.3 cps/kBq (8.8 cps/kBq) (R0, centre of field of view) and 2.3 cps/kBq (8.9 cps/kBq) (R10). The system scatter fraction was 21.4% in 2D at an energy of 375 keV (33.9% in 3D mode at a higher energy of 425 keV). Peak noise equivalent count rates (k=1) were 84.9 kcps at 43.9 kBq/ml (2D) and 67.6 kcps at 12.1 kBq/ml (3D). In image quality measurement the hot sphere to background contrast with 10- to 22-mm diameter spheres varied from 14% to 68%, being slightly better in 3D than in 2D mode. Cold sphere contrast was 67% in 2D and 59% in 3D mode. Conclusion GE’s new STE and VCT PET/CT systems have improved spatial resolution without loss in sensitivity. When compared with the LYSO crystal-based GE Discovery RX, the resolution and scatter fraction are comparable, the count rate capability is lower but the sensitivity is higher.