介入微导管技术中的DSA质控

目的探讨介入微导管技术中DSA的质量控制。方法常规Seldinger导管法,选择好DSA技术参数、高压注射器参数,常规呼吸训练及心理护理,利用“路径图”(roadmap)技术,将微导管超选至靶血管,进行造影及栓塞治疗时,对其DSA图像质量进行评价。结果检查151例病例(上腹部128例,胸部16例,头面部5例,盆腔2例),620个曝光采集序列(sequences),洗印966幅图像,图像质量优秀的497个序列,占80.2%;图像质量良好的109个序列,占17.5%;图像质量差的9个序列,占1.45%;造影失败5个序列,占0.86%。结论不同的病例、部位的图像采集应用不同的技术参数;使用非离子型造影剂有利于提高检查图像质量;肺部DSA要利用密度补偿;手推造影要注意压力控制、手脚配合及采集蒙片时机;术中护理与呼吸训练必不可少。     

探讨影响冠状动脉造影的设备技术因素

目的　探讨影响冠状动脉造影成像质量的技术因素。方法　随机抽取 35 0例冠状动脉造影检查 ,其中男 2 75例、女 75例 ,年龄 38～ 80岁 ,临床诊断 :不稳定型心绞痛 2 2 5例 ,急性心肌梗死 6 3例 ,陈旧性心肌梗死 4 2例 ,高血压、高脂血症 2 0例。 35 0例中有 2 80例既往有抽烟、饮酒史。多数病例有心前区疼痛病史和心电图缺血性改变。结果　　相关技术因素分析情况表技术因素图像质量Ⅱ级 (例 )Ⅲ级 (例 )导管位置 5 3投照体位 9 1移动摄影技术 15 1缩光器和滤过板技术 9造影剂注射流率 10 2合计 487结论　本组 3 5 0例图像质量评定结果 ,Ⅰ级 2 95例 ,占 83 % ;Ⅱ级 48例 ,占 15 % ;Ⅲ级 7例 ,占 2 %。操作技术因素 ,对冠状动脉造影成像质量有很大影响 ,它可能导致图像质量降级 ,并影响诊断。①合理使用对比剂的注射流率。常规采用注射延迟 ,这种注射对比剂的方法 ,可以充分显示冠状动脉充盈显影的全部过程。推注对比剂的压力及流速要适度 ,用力不够、流速不稳 ,图像显示不清晰 ,用力过度导管会反弹出冠脉口。本组有 10例Ⅱ级图像 ,就是由于对比剂注射流率不恰当和注射对比剂与采集图像配合不当 ,而导致图像质量降级。②灵活运用移动摄影。移动摄影是根据对比剂注入的剂量、血流状态和摄影范围来决定摄     

冠状动脉能谱CT单能量成像与混合能量成像质量的比较——静态模型的实验研究

目的通过模拟冠状动脉静态模型分析比较能谱CT宝石能谱成像(GSI)与混合能量成像的图像质量。材料与方法采用模拟冠状动脉静态体模,体模内共3支相同的模拟冠状动脉,管腔内斑块采用人造混合斑块(120 kVp下CT值约60.0～148.6 HU)伴有三种不同程度狭窄(25%、50%及75%)。在3支模拟冠状动脉内分别注入3种不同浓度的对比剂进行扫描,模型内对比剂碘浓度由低到高依次为6.25 mgI/ml、7.89 mgI/ml、14.06 mgI/ml,分别将其定为A、B、C组。采用GE Discovery CT 750 HD扫描仪,采集120 kVp下的混合能量模式(包括混合能量标准扫描和混合能量高清扫描标准重组)及GSI能谱扫描模式;每支模拟冠状动脉分别在每种狭窄处选取4个层面的感兴趣区进行测量,分别测量管腔内CT值、模拟斑块的CT值及背景噪声,计算各层面的对比噪声比(con-trast-to-noise ratio,CNR)。同时由两名专业影像医师根据图像显示情况对感兴趣区的轴位及冠状重组图像进行评分。通过CNR及主观评分的比较评价冠状动脉的图像质量。结果比较GSI序列40～140 keV图像的CNR,A～C组均在50～60 keV具有较好的CNR,比较60 keV单能量图像与混合能量图像不同狭窄率条件下A～C组CNR,除A组浓度25%及75%狭窄率的CNR间比较没有统计学差异,B、C组浓度单能量60 keV扫描模式CNR值均高于混合能量扫描模式,其差异有统计学意义。比较不同狭窄率条件下A～C组图像质量的主观评分,60 keV单能量图像与混合能量图像相比,在对比剂浓度较低时(A组及B组)其评分均高于混合能量图像,其差异有统计学意义,而对比剂浓度相对较高的C组内50%及75%狭窄率的GSI 60 keV单能量图像与混合能量模式图像比较图像质量评分无统计学差异性。结论冠状动脉狭窄模型运用宝石能谱CT扫描,在60 keV时能够获得最佳图像质量,优化图像的CNR,较冠状动脉常规混合能量扫描模式具有更好的图像质量。     

DR摄影曝光量的设定方法及图像质量的对比分析

目的:通过分析DR自动曝光处理(AEC)系统X线摄影仟伏值与成像质量的关系,确定AEC和手动曝光处理(FIXED)时最佳摄影条件。方法:以腹部摄影为例,选择DR腹部前后立位滤线器摄影模式,采用AEC系统,对CRDR-26型测试板进行摄影,统计不同仟伏值下图像的质量系数(QC),并进行统计学分析,取得最佳图像质量的摄影条件,并将该条件设定为FIXED时的摄影条件。采用以上摄影条件,分别利用AEC方式和FIXED对临床患者进行摄影,按照图像质量标准验证不同摄影模式下图像质量的差异。结果:小于80kV摄影条件下,不同摄影条件组间QC差异有统计学意义(P<0.05);当大于80kV时,不同摄影条件组间QC差异无统计学意义(P>0.05)。以最佳摄影条件取得的腹部X线图像,摄影质量较好以上分别占90.0%和87.5%,但对图像进行调节处理后,几乎没有明显差异。两者影像质量的差异无统计学意义。结论:DRAEC摄影通过增加仟伏值可以提高影像质量,但当仟伏值足够大时,再增加仟伏值并不能显著提高图像质量。影像质量与曝光剂量间存在一个最佳摄影条件和优化剂量,该最佳摄影条件和优化剂量可以作为FIXED方式摄影的设定条件。     

支气管动脉DSA的质量控制

目的：总结138例肺癌的．186次支气管动脉DSA及化疗药物灌注。就对比剂的选择及注射量、流量的应用、减影方式、帧频、密度补偿等对图像质量的影响以及支气管动脉化疗灌注的流率与患的耐受程度进行分析，提出质量控制措施。方法：Seldinger导管法，导管插至支气管动脉开口处行DSA检查。遮挡双侧肺野，注射对比剂流率0.5—1．0ml／s，总量5—7m1，延时0．5—1．0s减影至10s。使用离子型对比剂119次；非离子型对比剂67次。脉冲方式减影182次，帧频6—10F／S；连续方式4次；6F／S和30F／S各1次；10F／S2次；常规对患进行呼吸训练。结果：图像质量优秀的57例，造成图像质量差主要是呼吸性伪影有137次，其中使用离子型对比剂108次，非离子型对比剂29次；心脏搏动性伪影22次，10F／S脉冲方式11次；6F／S脉冲方式和连续方式出现11次，强透过出现8次，注射流率超过0．5m1／s有17例逆流。结论：①支气管动脉DSA，使用非离子型对比剂图像优质率明显高于使用离子型对比剂，特别是能有效抑制呼吸性移动伪影，在支气管动脉造影中应首选；②支气管动脉造影不宜使用连续方式，应选择曝光脉宽较窄的脉冲方式，采集频率不能少于10F／S，这样有利于降低心脏搏动性伪影的出现；③正确遮挡肺野，低流率造影，也是提高图像府号的有效手段。     

CT冠状动脉成像在冠心病诊断中的应用

目的:研究CT冠状动脉成像在冠心病早期诊断冠状动脉狭窄定性定量判读的作用。方法:对34例临床未发生急性冠脉综合征的冠心病患者,先后进行冠状动脉造影、128排双源CT冠状动脉成像。以冠状动脉造影为"金标准",计算CT冠状动脉成像敏感性、特异性、阳性预测值、阴性预测值。结果:①与冠状动脉造影相比,CT冠状动脉成像的敏感性为68%,特异性为97%,阳性预测值为89%,阴性预测值为90%。②CT冠状动脉成像有65个血管段图像质量差,约占12%,造成图像质量差的原因主要为钙化,心跳、呼吸伪影,少部分为管腔显示不良。结论:冠心病早期诊断中,CT冠状动脉成像可用作冠状动脉造影前筛选,CT冠状动脉成像阴性的患者不必行冠状动脉造影检查;CT冠状动脉成像阳性的患者,可行冠状动脉造影进一步确认病变。     

双源CT冠状动脉成像图像质量与影响因素的相关性分析

目的分析多种图像质量影响因素与图像质量的关系,探讨相应的解决方案。方法回顾性分析926例行双源CT(dual-source CT,DSCT)冠状动脉成像资料,分析其平均心率、心率变化、视野(FOV)、螺距(Pitch)值、采集心动周期数、对比剂注射流率、对比剂用量、触发阈值、触发时间等扫描参数与冠状动脉成像图像质量的相关性。结果影响因素中平均心率、心率变化及FOV与图像质量有统计学意义的相关关系。平均心率及心率变化与DSCT冠状动脉CTA图像质量呈负相关;FOV与图像质量呈正相关。心动周期、Pitch值、对比剂注射流率、对比剂用量、触发阈值、触发时间与图像质量无统计学意义的相关。结论冠状动脉CT成像图像质量受多种因素影响,其中心率、心率变化及FOV是影响图像质量的主要因素。     

双C臂冠状动脉DCM的质量控制

目的:分析利用运行双C臂提高冠状动脉造影图像质量的具体措施。方法:使用Siemens B1Cor Plus/TOP双C臂心血管造影机,采用Seldinger技术选择性插管至冠状动脉开口处,行双向冠状动脉数字电影模式(DCM)成像。结果:807例冠状动脉全部显示清楚。744例图像质量优(占92.19%),38例良,25例差。结论:使用双C臂DCM行冠状动脉造影能实现到位迅速、运行安全、体位角度准确的技术要求,缩短检查时间,提高冠状动脉造影的图像质量和安全性。     

数字化乳腺X线摄影体位设计技术探讨

目的: 探讨数字化乳腺摄影的摆位操作技巧,以提高图像质量.材料和方法: 回顾性分析6240例患者的数字化乳腺摄影的图像资料,对每一个摄影位置的摆位方法做主观评价,对图像显示效果进行分级.结果: 25087幅图像中,Ⅰ级片24655幅,占总数的98.3%;Ⅱ级片383幅,占总数的1.5%;重拍片49幅,占0.2%.结论: 精心的体位设计,在数字化乳腺摄影中,是获得高质量乳腺摄影图像的必要条件.     

A Comparative Study on Simulated Coronary Artery with Artificial Plaques with Gemstone Spectral Imaging and Conventional Polychromatic X-ray Imaging

目的 通过模拟冠状动脉静态模型分析比较能谱CT宝石能谱成像(GSI)与混合能量成像的图像质量.材料与方法 采用模拟冠状动脉静态体模,体模内共3支相同的模拟冠状动脉,管腔内斑块采用人造混合斑块(120 kVp下CT值约60.0-148.6 HU)伴有三种不同程度狭窄(25％、50％及75％).在3支模拟冠状动脉内分别注入3种不同浓度的对比剂进行扫描,模型内对比剂碘浓度由低到高依次为6.25 mgI/ml、7.89 mgI/ml、14.06 mgI/ml,分别将其定为A、B、C组.采用GE Discovery CT 750 HD扫描仪,采集120kVp下的混合能量模式(包括混合能量标准扫描和混合能量高清扫描标准重组)及GSI能谱扫描模式;每支模拟冠状动脉分别在每种狭窄处选取4个层面的感兴趣区进行测量,分别测量管腔内CT值、模拟斑块的CT值及背景噪声,计算各层面的对比噪声比(contrast -to-noise ratio,CNR).同时由两名专业影像医师根据图像显示情况对感兴趣区的轴位及冠状重组图像进行评分.通过CNR及主观评分的比较评价冠状动脉的图像质量.结果 比较GSI序列40～140 keV图像的CNR,A～C组均在50～60 keV具有较好的CNR,比较60 keV单能量图像与混合能量图像不同狭窄率条件下A～C组CNR,除A组浓度25％及75％狭窄率的CNR间比较没有统计学差异,B、C组浓度单能量60 keV扫描模式CNR值均高于混合能量扫描模式,其差异有统计学意义.比较不同狭窄率条件下A～C组图像质量的主观评分,60 keV单能量图像与混合能量图像相比,在对比剂浓度较低时(A组及B组)其评分均高于混合能量图像,其差异有统计学意义,而对比剂浓度相对较高的C组内50％及75％狭窄率的GSI 60 keV单能量图像与混合能量模式图像比较图像质量评分无统计学差异性.结论 冠状动脉狭窄模型运用宝石能谱CT扫描,在60 keV时能够获得最佳图像质量,优化图像的CNR,较冠状动脉常规混合能量扫描模式具有更好的图像质量.     

64排螺旋CT冠脉成像中双筒注射技术探讨

目的:探讨64排螺旋CT冠状动脉成像中,应用双筒注射技术消除上腔静脉伪影的作用。方法:182例疑冠心病的患者行64排螺旋CT冠状动脉成像,采用双筒高压注射器,高速注射对比剂后立刻以相同流率注射30~50ml生理盐水。评价上腔静脉伪影对图像质量的影响,图像质量分优、良和差3个等级。结果:本组中CT冠脉成像质量优者占85%,良占14%,差占1%。结论:通过采用双筒高压注射器,可消除上腔静脉和右心房内潴留对比剂而产生的伪影,提高64排螺旋CT冠状动脉成像质量。     

Initial experience with the intravascular contrast agent NC100150-injection (Clariscan) for breath-hold and navigator-gated magnetic resonance coronary artery imaging

PURPOSE: To examine magnetic resonance coronary artery imaging after NC100150-Injection. MATERIALS AND METHODS: Breath-hold and navigator-gated images were acquired in five patients. RESULTS: Breath-hold image quality, coronary artery-fat SDNR, and coronary artery SNR improved. Respiratory artifacts due to reduced liver signal intensity degraded navigator-gated image quality. CONCLUSION: NC100150-Injection improves breath-hold coronary artery imaging. Navigator-gated acquisitions should use techniques that are insensitive to T2* effects.     

Coronary MR angiography during peak-systole: Work in Progress

The purpose of this study is to compare the quality of images of coronary arteries obtained with two-dimensional breath-hold coronary MR angiography during peak systole and mid diastole. Two-dimensional coronary MR angiography was performed in eight normal volunteers at peak systole and in mid diastole with a commercial 1.5-T MR imager. An ultrafast gradient-echo sequence with incremented flip angle series and k-space segmentation was used. The image quality grade, length, and proximal diameter of each visualized coronary artery were measured. The highest quality images in systole and diastole were compared. Coronary MR angiography provided high quality images in systole and diastole in 14 of 16 coronary vessels (87.5%). In 8 of 14 vessels (57%), there was no visible coronary MR angiogram image degradation when comparing peak systolic with mid-diastolic images. In 4 of 14 vessels (29%), there was mild MR image degradation. There was significant MR image degradation in only one case (7%). And in one case (7%), there was mild image improvement during systole. The width and length of the visualized coronary vessels did not change significantly from diastole to systole. Existing two-dimensional breath-hold coronary MR angiography provides MR images during peak systole and mid-diastole with little or no perceptible difference in quality.     

Dynamic intravenous coronary angiography using 2D monochromatic synchrotron radiation.

A method of examination for coronary artery disease that is less invasive and easier than coronary angiography (CAG) has been sought. We have developed a dynamic intravenous coronary angiography (IVCAG) system using synchrotron radiation (SR) and have used it clinically. Four patients suspected of having angina pectoris underwent IVCAG. An SR beam was reflected asymmetrically with a silicon crystal to produce a wide (150 mm x 80 mm) and monochromatic (37 keV) X-ray beam, with an energy level to achieve high sensitivity to the contrast agent. Following an intravenous injection of contrast agent, irradiation was applied for 4 ms periods at 33 ms intervals for dynamic IVCAG at 30 images s-1. Images were acquired with an image intensifier and recorded with a digital fluorography system. The dynamic images permitted clear visualization of the coronary arteries and permitted evaluation of coronary anatomy. Two patients exhibited no stenotic lesions, one patient had a 90% stenosis in the right coronary artery, and the remaining patient had a 25% stenosis at the site of previous percutaneous transluminal coronary angioplasty in the left anterior descending artery (LAD). The total irradiation doses used for IVCAG were less than those for conventional angiography. Dynamic IVCAG can be readily used for the evaluation of coronary arteries.     

Contrast-enhanced 4D radial coronary artery imaging at 3.0 T within a single breath-hold.

Coronary magnetic resonance angiography data are usually acquired during mid-diastole of each heartbeat to minimize cardiac motion related artifacts. The proper trigger delay time, which may vary widely among subjects, must be determined individually for each subject before data acquisition to achieve optimal image quality. These complications could be resolved by acquiring contiguous cardiac phase images through the cardiac cycle. In this study, we used a radial sampling technique to acquire 3D cine coronary artery images at 3 T within a single breath-hold. An extravascular, paramagnetic contrast agent was i.v. administered to improve the blood signal intensity. Relatively high temporal resolution and spatial resolution were achieved simultaneously with radial sampling, parallel data acquisition, and interleaved sliding window image reconstruction. Volunteer studies demonstrate the feasibility of this technique in acquiring 4D coronary artery images and the flexibility in postprocessing of 3D image sets.     

Abdominal phase-contrast MR angiography: Breath-Hold versus non-breath-hold techniques

Breath-hold magnetic resonance (MR) imaging is now replacing many non-breath-hold pulse sequences in the upper abdomen because of faster imaging times and improved image quality. The authors compared non-breath-hold cine phase-contrast (PC) and breath hold 2D phase-contrast (2DPC) magnetic resonance (MR) angiograms of the main portal vein (MPV) and superior mesenteric artery (SMA) in 12 volunteers. All angiograms were graded in overall image quality, vessel conspicuity, and signal-to-noise ratios (SNR). In the MPV MR angiograms, the breath-hold 2DPC sequence produced better images than the non-breath-hold cine PC sequence as graded by overall image quality (P=.016) and SNR (P=.004). Conversely, in the SMA MR angiograms, the non-breath-hold cine PC sequence produced better images than the breath-hold sequence in terms of overall image quality (P=.008) and SNR (P=.008). By reducing the most significant cause of image artifacts, (ie, using a breath-hold 2DPC sequence to decrease respiratory misregistration of the MPV, and using a cardiac-gated cine PC sequence to minimize pulsatile artifacts of the SMA), one can clearly optimize the quality of MR angiography.     

MR coronary angiography with SH L 643 A: initial experience in patients with coronary artery disease

PURPOSE: To prospectively assess the accuracy of breath-hold three-dimensional magnetic resonance (MR) coronary angiography with the gadolinium-based intravascular contrast agent SH L 643 A in patients with coronary artery disease. MATERIALS AND METHODS: Twelve patients (seven men, five women; age range, 46-78 years; mean age, 61.3 years) with angiographically proved coronary artery disease (luminal narrowing >50%) underwent breath-hold three-dimensional MR coronary angiography before and after injection of SH L 643 A (0.1 mmol gadolinium per kilogram body weight). For all MR examinations, signal-to-noise ratio and contrast-to-noise ratio were measured. Image quality was assessed with a four-point scale. Conventional angiograms and MR angiograms were evaluated for depiction of the left main, proximal and middle left anterior descending, proximal left circumflex, and proximal and middle right coronary artery segments in a blinded fashion by two experienced readers in consensus. Results of this evaluation were compared by using a paired Student t test. P < .05 was considered to indicate a statistically significant difference. RESULTS: For the 72 coronary artery segments, the contrast-to-noise ratio significantly improved after administration of SH L 643 A, compared with the prior ratio (9.8 +/- 5.1 [standard deviation] vs 23.0 +/- 8.7; P < .01), whereas the difference in signal-to-noise ratio did not reach statistical significance (25.2 +/- 11.4 vs 29.5 +/- 9.8; P > .3). Image quality significantly improved from a mean of 2.0 +/- 0.9 for nonenhanced images to 2.9 +/- 0.9 (P < .03) for contrast material-enhanced images. The proportion of segments for which images were nondiagnostic decreased from 38% to 10% with application of SH L 643 A. Overall sensitivity and specificity of contrast-enhanced MR coronary angiography for detection of coronary artery disease were 80% and 93%, respectively, and accuracy was 87%. CONCLUSION: Use of SH L 643 A improves detection of coronary artery disease at three-dimensional MR coronary angiography.     

Assessment of coronary artery bypass grafts: value of different breath-hold MR imaging techniques

OBJECTIVE: Our aim was to evaluate the patency of coronary artery bypass grafts and to detect graft stenosis using different breath-hold MR imaging techniques. SUBJECTS AND METHODS: Twenty-two patients with 59 grafts (14 internal mammary artery grafts and 45 saphenous vein grafts) and 76 distal anastomoses (singular and sequential grafts) were studied using a 1.5-T scanner. A two-dimensional T2-weighted breath-hold half-Fourier acquisition single-shot turbo spin echo (HASTE) sequence and a three-dimensional breath-hold contrast-enhanced MR angiography sequence (fast imaging with steady-state free precession) were performed. For MR angiography, a bolus of 20 ml of gadopentetate dimeglumine was used. Time delay for contrast injection was calculated by a test bolus. The gold standard was coronary angiography performed within 14 days of MR imaging. All images were evaluated independently by two radiologists. RESULTS: With the HASTE sequence, 95% of the patent grafts were recognized (42/44); specificity was 93% (14/15). MR angiography had both a sensitivity (41/44) and specificity (14/15) of 93%. Interobserver agreement for both sequences was good (Cohen's kappa = 87%; McNemar test, p = 56%). Forty-nine (83%) of 59 patent distal graft anastomoses were revealed with the HASTE sequence; 38 (64%) of 59 were seen on contrast-enhanced angiography. With HASTE imaging, only two of eight hemodynamically significant graft stenoses were detected. MR angiography revealed only four of eight significant graft stenoses. CONCLUSION: The HASTE sequence and three-dimensional MR angiography proved to be useful MR techniques when evaluating the patency of coronary artery bypass grafts. However, reliable detection of graft stenosis does not yet seem possible with these imaging techniques.     

前瞻性心电门控多期相重建在儿童冠状动脉CT检查中的应用

目的:探讨前瞻性心电门控多期相重建技术在儿童冠状动脉CT成像中的应用。方法:回顾性选取2017年6月-2018年5月在本院行冠状动脉CTA检查且心率为100~120次/分的60例患儿作为对照组,采用回顾性心电门控多相位扫描技术,重建40%、45%、50%、70%、75%和80%R-R间期的6组图像,选取其中冠状动脉成像质量主观评分最高的期相。前瞻性选取2018年6月-2019年5月在本院行冠状动脉CTA检查且心率为100~120次/分的60例2~4岁患儿作为实验组,采用前瞻性心电门控多期相重建技术,重建40%、45%和50%R-R间期的三组图像,选取其中冠状动脉成像质量主观评分最高的期相。两组患儿采用相同的扫描参数、对比剂用量和注射方式。对比两组中CT扫描的辐射剂量和冠状动脉血管成像质量。结果:实验组中冠状动脉40%、45%和50%R-R间期重建图像的主观评分分别为4.02±0.70、4.88±0.33和4.07±0.73,对照组中冠状动脉40%~80%R-R间期重建图像的主观评分依次为2.33±1.50、4.90±0.52、2.30±1.38、2.30±1.38、1.30±0.62和1.18±0.47;两组中最佳期相均为45%R-R间期,这2个期相的冠状动脉重建图像的主观评分之间的差异无统计学意义(P>0.05)。CTA扫描的有效辐射剂量,实验组为(0.42±0.07)mGy,对照组为(2.87±0.48)mGy,实验组较对照组降低85%,差异有统计学意义(P<0.05)。两组中对比剂用量,实验组为(19.24±5.12)mL,对照组为(18.75±4.26)mL,差异无统计学意义(P>0.05)。结论:前瞻性心电门控多期相重建技术可应用于儿童冠状动脉CT成像,在不影响冠状动脉成像质量的条件下,可显著降低患儿接受的辐射剂量。