屏气三维快速平衡稳态进动序列在磁共振冠状动脉成像中的可靠性研究

目的 :评价屏气三维快速平衡稳态进动 ( 3D FIESTA)序列在冠状动脉磁共振成像 (CMRA)中的可靠性。材料和方法 :67例受检者 ,采用心电触发的三维FIESTA序列 ,呼气末屏气采样 ,在 8个不同层面方向定位显示冠状动脉各主支 ,包括右冠 (RCA)、左主支 (LM)、左前降支 (LAD)和左回旋支 (LCX) ,以 0 -IV级图像质量体系为参照 ,评分II级以上作为可接受标准 ,采用美国心脏协会 (AHA)的冠状动脉分段标准评价其显示的长度和范围。结果 :67例受检者能够屏气配合完成检查的 65例 ,检查适用率为 97.0 % ;对AHA 18、19段 (RCA近段和中段 )、AHA 1、2 (LM)、AHA 3、5、7段 (LAD近段和中段 ) ,AHA 10段 (LCX近段 )的显示可重复性为 10 0 % ;对AHA 9、14、2 1段 (LAD、LCX和RCA的远段 )的显示可重复性分别为 95 .3 8%、72 .3 1%、96.92 %。结论 :此三维FIESTA序列可以稳定显示冠状动脉主要分支的近段和中段 ,初步具备临床应用的价值。     

磁共振冠状动脉成像定位方法

目的 摸索磁共振冠状动脉成像(MRCA)的扫描定位方法。方法 89例受检者，用快速平衡稳态成像(FIESTA)序列获得标准四腔心位、左室和右室长轴位的电影图像并确定舒张中期触发延迟时间，在此基础上用脂肪抑制的三维FIESTA序列在呼气末屏气定位扫描冠状动脉右支(RCA)、左主干(LM)、前降支(LAD)和回旋支(LCX)，以美国心脏协会(AHA)推荐的冠状动脉解剖分段法评价定位显示的可重复性。结果 86例受检者能够屏气配合完成检查，适用效率为96．63％；9个位置可以稳定地显示冠状动脉各主支，各位置综合对RCA近段和中段(AHA-18、19段)、LM全长(AHA-1、2)、LAD近段和中段(AHA-3、5、7段)，LCX近段(AHA-10段)的显示可重复性为100％；对LAD、LCX和RCA的远段(AHA-9、14、21段)的显示可重复性分别为94．19％、72．09％、96．51％。结论 MRCA定位方法简单实用，可以稳定显示冠状动脉主要分支的近段和中段，初步具备临床应用的价值。     

磁共振成像显示冠状动脉起源异常1例

患者男,53岁。反复发作心绞痛10余年,静息间期ECG检查未见异常,心肌酶学检查正常,心脏超声检查无形态及运动异常。冠状动脉造影显示左前降支（LAD）狭窄50％左右,左回旋支（LCX）无狭窄征象,右冠状动脉（RCA）未显影。使用ECG触发的屏气三维快速平衡稳态进动序列（FIESTA）进行冠状动脉磁共振成像（MRA）,RCA与左主干（LM）并行起源左冠窦,经过肺动脉主干和升主动脉间期进入右侧房室沟,并可见粗大的圆锥支（PB）发出,RCA近段光滑清晰、中段管壁不规则,考虑狭窄大于50％;LAD中段第一对角支以远部分可见节段性冠状动脉管腔狭窄和管壁增厚改变,与冠状动脉造影显示一致。     

呼吸导航3D BTFE与双反转TSE序列对冠状动脉成像质量的评价

目的 比较呼吸导航三维平衡超快场同波(3D balanced turbo field echo,3D BTFE)与双反转快速自旋回波(TSE)冠状动脉磁共振血管成像(CMRA)方面有无差异.资料与方法 对28例分别利用呼吸导航3D BTFE和双反转TSE序列进行CMRA.在图像后处理[最大密度投影(MIP)、最小密度投影(MinIP)]后,对图像进行半定量评价(0～4级),并对评分≥2者进行统计学分析;采用标准的冠状动脉分段方式评价两种不同方法目标血管显示的成功率;对两种不同方法图像信噪比(SNR)、对比噪声比(CNR)和图像质量的评分进行比较.结果 评分≥2者25例.(1)利用VCG触发和呼吸导航技术能较好地抑制心跳和呼吸运动伪影;(2)两种方法可以显示绝大部分目标节段,二者在右冠状动脉(RCA)近中段、左主干(LM)、左前降支(LAD)近中段、左回旋支(LCX)近中段显示率接近,RCA远段的显示率分别为75%和54%;(3)两种方法的RCA、LM、LAD和LCX的显示长度分别为97.38/89.14、15.34/14.19、52.50/35.41和50.92/49.16 mm;(4)两种方法SNR、CNR和质量评分分别为108.86/4.66、67.77/28.01和3.50/2.54;(5)两种方法的单次扫描时间分别为1 min 45 s和2 min 40 s.结论 (1)两种方法的冠状动脉主干的显示率较高(RCA和LCX远段相对较低);(2)两种方法对患者的配合要求不高,均可在自由呼吸的情况下得到冠状动脉影像;(3)双反转TSE序列在冠状动脉目标节段的显示率上与3D BTFE序列接近,但是,其图像质量较后者差,稳定性不佳,在成像时间上也没有优势;(4)3D BTFE序列在冠状动脉目标节段的显示率、图像质量以及成像时间方面具有优势.     

按患者体重分期注射造影剂方案在64层螺旋CT冠状动脉成像中的应用

目的评价按患者体重设计的分期注射造影剂方案在64层螺旋CT冠状动脉成像(MSCTCA)中的应用,并与传统注射法比较。方法 100例拟接受MSCTCA患者随机分为传统注射组(共50例,先注射造影剂85 mL,后注射生理盐水30 mL)和分期注射组(50例)。分期注射组按患者体重(<60,61～74,>75 kg)又分为3个亚组。3亚组患者均接受3期注射:1期,均注射生理盐水16 mL;2期,分别注射造影剂70,75和80 mL;3期,分别注射造影剂与生理盐水(3∶7)混合物30,30和40 mL。由两名经验丰富的放射医师盲法评价冠状动脉各分支(15节段)显示情况与图像质量,并比较两种注射方案的差异。结果分期注射组中右冠状动脉(RCA)远段、右后降支(RPD)、左前降支(LAD)远段、第一第二对角支(D1、D2)、左回旋支(LCX)远段、左室后支(LVP)及左后降支(LPD)的图像质量明显优于传统注射组(P<0.05),但是两组间RCA近段、RCA中段、左主干(LM)、LAD近段与中段、LCX近段及钝缘支(BE)的图像质量无明显差异(P>0.05)。结论在MSCTCA中,分期注射方案较传统注射法明显提高了冠脉动脉远端分支的强化程度,提供了更好的图像质量,因而能更好地满足临床诊断要求。     

3.0 T MR增强冠状动脉造影3PPS分段采集与全心采集的定量对比分析

目的 采用定量的方法评价3T增强冠状动脉磁共振血管成像(Coronary MR Angiography,CMRA)对冠状动脉的显示能力和图像质量.资料与方法 10例临床疑为冠心病的患者接受了3 T增强CMRA检查,采集技术包括3点定位(3PPS)分段采集和全心采集两种方式,使用Soap-Bubble软件对两种技术采集的CMRA数据进行后处理重组并通过测量冠状动脉各主要分支的长度、直径及血管的锐利度,定量评判CMRA的图像质量.结果 3PPS分段采集CMRA各主要分支的测量值为:长度:右冠状动脉(RCA)(132±13) mm,左冠状动脉系统,即左主干 左前降支(LM LAD)(112±16) mm,左旋支(LCX)(64±11) mm;直径:RCA(3.8±0.5) mm,LM LAD(3.3±0.2) mm,LCX(2.9±0.5) mm;锐利度分别为(49±10)%,(47±11)%,(44±16)%.全心采集:长度:RCA(128±21) mm,LM LAD(101±15) mm,LCX(52±13) mm;直径:RCA(3.5±0.6) mm,LM LAD(3.1±0.4) mm,LCX(3.0±0.7) mm;锐利度分别为(35±15)%,(33±11)%,(30±12)%.两者间的血管锐利度和图像质量差异均有统计学意义(P＜0.05),但长度和直径的差异无统计学意义(P＞0.05).结论 3PPS分段采集较全心采集具有更好的血管锐利度和图像质量,在CMRA的采集方式上建议尽量采用分段采集技术.     

3.0T磁共振全心冠脉成像和靶容积冠脉成像方法的对比研究

目的:初步评价3.0T磁共振全心冠脉成像显示正常冠状动脉长度及成像质量的价值。材料和方法:应用3.0TMR对15名志愿者分别进行全心成像及靶容积成像。对比两种成像方式显示的血管长度、信噪比、对比信噪比及图像质量。结果:全心成像RCA(10.41±2.37cm)、LM/LAD(8.47±1.40cm)的长度显示大于靶容积成像(9.82±1.44cm和8.24±0.85cm),(P<0.05);显示LCX长度两种成像方式无差异(4.75±0.86cm和4.65±0.91cm,P>0.05)。信噪比及对比信噪比无显著差异。RCA、LAD远段全心成像质量评分(3.1±1.0;2.8±1.1)高于靶容积成像(2.5±1.2;2.5±1.2,P<0.05);其余各节段图像质量评分均无明显差异。结论:3.0 T磁共振全心冠状动脉成像是可行的;全心冠脉MRA在对冠状动脉血管远端的显示上优于靶容积成像。     

屏气三维快速平衡稳态进动序列对冠状动脉狭窄的诊断效能

目的以普通冠状动脉导管造影为参照,评价屏气三维快速平衡稳态进动(FIESTA)序列对冠状动脉狭窄的显示效能。方法连续33例患者在冠状动脉导管造影检查的3周内接受冠状动脉MR血管成像(CMRA)检查,将冠状动脉狭窄划分成0%、0%~25%、25%~50%、50%~75%,75%~100%共5个级别,对两者判断的结果逐段进行比较。结果CMRA对区分>50%和<50%狭窄的准确度、敏感度和特异度分别为843%、848%和841%,阴性预测值为923%;对区分50%~75%与75%~100%狭窄的准确度、敏感度和特异度均为615%。结论屏气三维FIESTA冠状动脉成像序列对具有血流动力学意义狭窄的排除具有一定的实用价值,但是更细致的分级受限。     

16层螺旋CT冠状动脉血管成像技术临床应用

目的:探讨16层螺旋CT冠状动脉成像技术临床应用价值。方法:对45例临床诊断或可疑冠心病的住院患者行16层螺旋CT冠状动脉回顾性心电门控平扫及增强扫描。将增强扫描图像传送到Wizard图像工作站进行最大密度投影(MIP)、多平面重组(MPR)、曲面重组(CPR)、容积再现技术(VRT)及平带多平面重组(RMPR)。并将VRT及MIP重组像为参照,用平扫图像对冠状动脉各支段进行钙化积分。结果:左冠状动脉主干(LM)、左前降支近中段(LAD1、LAD2)、第一对角支(D1)、左回旋支(LCX)及右冠状动脉近段(RCA1)显示均45例(100%),左前降支远段(LAD3)23例(51%),第二对角支(D2)30例(67%),第三对角支(D3)24例(53%),第一左缘支(M1)36例(80%),第二缘支(M2)28例(62%),右冠状动脉中段(RCA2)41例(91%),右冠状动脉远段(RCA3)43例(96%)及后降支(PDA)34例(76%)。左冠状动脉主干钙化12例(27%),左前降支近中段钙化有29例(64%),左回旋支钙化例数22例(49%),右冠状动脉近中段钙化有24例(53%)。结论:16层螺旋CT可对冠状动脉进行钙化积分并准确显影,是冠状动脉粥样硬化疾病筛选和诊断的首选方法。     

宽体探测器CT对法洛四联症患儿冠状动脉成像效果研究

目的:研究法洛四联症(TOF)患儿行宽体探测器CT心脏成像时冠状动脉的图像质量和辐射剂量,初步探讨其临床价值。方法:115例TOF患儿纳入研究,按患儿年龄分为4组,A组(年龄≤6月,39例);B组：(6月<年龄≤1岁,36例);C组：(1岁<年龄≤3岁,24例);D组：(3岁<年龄≤12岁,16例)。将冠状动脉分为11个节段,采用4分制评分法评价冠状动脉各节段图像质量,统计冠状动脉异常(CAAs)情况。记录主动脉根部CT值、噪声、信噪比(SNR)及对比噪声比(CNR)评价客观图像质量。分析各组容积剂量指数(CTDIvol)、剂量长度乘积(DLP)和有效剂量(ED)相关性。结果:冠状动脉总显示率92.9%,开口、近段、中段、远段显示率顺次为100%(227/227)、99.1%(456/460)、93.9%(216/230)、79.4%(274/345)。冠状动脉开口、左主干、前降支(LAD)近段、右冠状动脉(RCA)近段显示率均为100%,回旋支(LCX)远段显示率最低为58.3%(67/115)。TOF患儿CAAs发生率10.4%。各组客观图像质量无明显差异(P&g...     

Navigator echo-based respiratory gating for three-dimensional MR coronary angiography: reduction of scan time using a slice interpolation technique

PURPOSE: The aim of the study was to compare a conventional respiratory-gated 3D MR coronary angiographic technique (conventional MRCA) with a respiratory-gated 3D MR coronary angiographic technique that includes a slice interpolation technique (slice interpolation MRCA). Both MRCA techniques were compared based on the quality of visualization of the coronary arteries and the diagnostic accuracy in identifying hemodynamically significant coronary artery stenoses. METHOD: Forty patients with known proximal coronary artery stenosis after conventional CA were examined on a 1.5 T scanner, that is, 20 patients with each sequence. A 6 point grading system (0 = worst quality, 5 = best quality) was used to evaluate and compare the image quality. The length and proximal diameter of the depicted coronary arteries were measured. Detection of coronary artery stenoses was compared with that obtained by conventional CA by two blinded readers. RESULTS: With the slice interpolation technique, the average scan time of the entire heart was reduced by approximately 40%. With use of conventional MRCA, 69% of all proximal and middle coronary artery segments were visualized with a sufficient image quality; with the slice interpolation technique, 79% of these segments were depicted adequately. For the assessment of stenoses, sensitivity was 71% and specificity was 53% for conventional MRCA and 72 and 60% for slice interpolation MRCA, respectively. These differences in sensitivity and specificity were statistically not significant. CONCLUSION: The application of a slice interpolation technique reduces the scan time, maintains a comparable sensitivity and specificity for the assessment of coronary artery stenoses, and increases the number of completely identified coronary artery segments compared with the conventional technique.     

Improvement of image quality with beta-blocker premedication on ECG-gated 16-MDCT coronary angiography

OBJECTIVE: The objective of our study was to assess the effect of beta-blockers on image quality of ECG-gated 16-MDCT coronary angiography. MATERIALS AND METHODS: Coronary CT angiography was performed in two groups: group 1, 24 volunteers (mean age, 50 years; mean heart rate, 69 beats per minute [bpm]; range, 47-97 bpm); and group 2, 15 patients with current ischemic heart disease (mean age, 54 years; mean heart rate, 54 bpm; range, 48-69 bpm) who were premedicated with 20-40 mg of oral propranolol 1 hr before the study. CT scans were obtained on a 16-MDCT scanner with a 12 x 0.75 mm collimation and 420-msec rotation using nonionic contrast material (80 mL; injection rate, 4 ml/sec). Images were reconstructed at 30-80% of the cardiac cycle in increments of 5%. Image quality of the following eight coronary segments was assessed by two radiologists in consensus: left main coronary artery; proximal and middle segments of the left anterior descending (LAD) and left circumflex (LCX) coronary arteries; and the proximal, middle, and distal segments of the right coronary artery (RCA). Image quality was assessed, using a 5-point grading scale, as grades 1-5. Images assessed as grade 4 or 5 were considered to be of diagnostically acceptable quality. RESULTS: In group 1, grade 4 or 5 image quality was achieved for visualization of 92% of the left main coronary arteries; 96% of the proximal LAD coronary arteries; 88% of the middle LAD, proximal LCX, and middle LCX coronary arteries; 83% of the proximal RCAs; 58% of the middle RCAs; and 96% of the distal RCAs. In group 2, this level of image quality was achieved in 100% of the left main coronary arteries, proximal and middle LAD arteries, and proximal LCX arteries; 87% of the middle LCX arteries; and 93% of the proximal, middle, and distal RCAs. CONCLUSION: Reduction of heart rates with beta-blocker premedication improves the image quality of CT coronary angiography, especially in terms of the visualization of the right coronary artery.     

Recurrent coronary artery stenosis: assessment with three-dimensional MR imaging

PURPOSE: To assess the diagnostic value of three-dimensional coronary magnetic resonance (MR) angiography with fat saturation and navigator echo in the setting of restenosis after percutaneous transluminal coronary angioplasty (PTCA). MATERIALS AND METHODS: Thirty consecutive patients who had PTCA and were referred for elective coronary reangiography underwent MR imaging and coronary angiography. The pulse sequence was a cardiac triggered, single-slab, three-dimensional, gradient-echo sequence, employing a spin-echo navigator echo measurement to track the variation of the diaphragm during the scan. The following segments of the coronary arteries were included in this prospective study: left main coronary artery, proximal and middle left anterior descending, proximal and middle left circumflex, proximal and middle right coronary artery, and intermediate branch, if present. The quality of the MR images was graded from 0 to 5. RESULTS: In total, 221 coronary artery segments could be identified. Mean image quality was 3.3. Overall accuracy for segments with an image quality of grade 2 or more was 90%. To achieve a positive predictive value >70% for a significant stenosis/restenosis, only segments with quality >/=3 could be assessed, whereas an acceptable negative predictive value could be achieved for nearly all segments. CONCLUSION: Our preliminary data suggest that MR coronary angiography may be most helpful as a screening test in selected patients to exclude clinically relevant stenoses or to assess restenoses after PTCA or in patients in whose coronary angiography is relatively contraindicated.     

3D FIESTA pulse sequence for assessing renal artery stenosis: is it a reliable application in unenhanced magnetic resonance angiography?

Objectives

To assess the capability of the three-dimensional (3D) Fast Imaging Employing Steady-State Acquisition (FIESTA) sequence in evaluating renal artery stenosis (RAS).

Methods

We retrospectively analysed 79 patients referred for suspected RAS, examined by 3D FIESTA and contrast-enhanced magnetic resonance angiography (CE-MRA), using a 1.5T whole-body scanner. Image quality was assessed as well as the presence and grade of RAS. Patients with RAS?≥?50 % were evaluated for possible digital subtraction angiography (DSA). Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy of 3D FIESTA were calculated with ROC analysis using CE-MRA and DSA as the standard of reference.

Results

A total of 186 renal arteries were assessed; 36 had RAS?≥?50 % demonstrated by CE-MRA. Ten patients underwent DSA, for a total evaluation of 22 arteries. Sensitivity, specificity, NPV, PPV, and accuracy of 3D FIESTA were 91.7 %, 100 %, 98 %, 100 %, and 98 %, respectively, as compared to CE-MRA, and 88.2 %, 100 %, 71.4 %, 100 %, and 91 %, respectively, as compared to DSA. The area under the ROC curve (AUC) of 3D FIESTA as compared to CE-MRA and DSA was 0.958 and 0.941, respectively.

Conclusions

Our study demonstrated the capability of the 3D FIESTA sequence in evaluating RAS, with high-quality images and good diagnostic accuracy.

Key Points

? The 3D FIESTA sequence provides a robust evaluation of RAS. ? The 3D FIESTA sequence allows non-invasive evaluation of the renal arteries. ? The 3D FIESTA sequence could be a useful tool in evaluating RAS.     

磁共振3DFIESTA及3DT1SPGR序列显示舌咽神经及血管压迫的诊断价值

 目的探讨磁共振3DFIESTA及3DT₁SPGR序列显示舌咽神经及血管压迫的诊断价值。方法对5例(10根神经)舌咽神经痛患者及17位(34根神经)健康志愿者共44根舌咽神经同时行3DFIESTA及3DT₁SPGR两序列成像,并对图像进行3D后处理重建,对图像质量及血管与舌咽神经的关系进行分析比较。结果两种序列显示舌咽神经图像质量比较,3DFIESTA序列优质图像43根神经(98%)明显多于3DT₁SPGR序列19根神经(43%),而劣质图像3DT₁SPGR序列25根神经(57%),FIESTA序列1根神经(2%)。3DFIESTA序列图像质量明显好于3DT₁SPGR序列(χ²=31.44,P<0.001)。5例舌咽神经痛患者中血管紧贴舌咽神经者6根神经(60%),而健康志愿者血管紧贴舌咽神经者8根神经(23%),舌咽神经痛患者血管紧贴舌咽神经者较健康志愿者多,且与临床表现相符合。结论在舌咽神经检查中利用3DFIESTA序列显示舌咽神经图像质量较好,同时做3DT₁SPGR序列,利用其血管呈现高信号的特点,对舌咽神经痛血管紧贴神经的诊断更加有益。     

多层螺旋CT冠状动脉成像临床应用价值探讨

目的 探讨冠状动脉多层螺旋CT成像的临床应用价值。资料与方法 38例冠状动脉进行多层螺旋CT血管造影,利用多种重建方法进行重建,分析冠状动脉的成像质量及其显示率,以及冠状动脉疾病的影像特点。结果 图像质量的优良率：优28．9％(11／38),良60．5％(23／38),差10．5％(4／38),优良率为89．5％(34／38);冠状动脉分段显示率为：右冠状动脉近段100％(38／38),中段76．3％(29／38),远段60．5％(23／38);左冠状动脉前降支近中段100％(38／38),远段81．6％(31／38),左回旋支近段100％(38／38),远段55．3％(21／38)。发现冠状动脉管壁欠光滑18例,钙化8例,管腔充盈缺损2例,冠状动脉仿真内镜发现冠状动脉夹层1例,管腔狭窄3例。结论 多层螺旋CT冠状动脉成像可以作为冠心病的一种筛选手段。     

胎儿磁共振成像序列的对比研究及应用

目的:比较单次激发快速自旋回波序列(SSFSE)和快速成像稳态采集序列(FIESTA)对胎儿解剖结构和病变的显示能力,探讨两种快速成像序列在胎儿MRI中的临床应用价值。方法:82例中晚期妊娠孕妇行单次激发快速自旋回波序列和快速成像稳态采集序列扫描,并根据图像平均信号强度、图像质量和图像伪影等方面对两个序列在胎儿解剖结构和病变的显示能力方面做出统计学分析。结果:两种序列对胎儿解剖结构和异常病变的显示各有优点和不足,SSFSE和FIESTA均能清楚显示胎儿正常脏器的解剖结构和异常病变。SSFSE的平均信号强度和分辨力要高于FIESTA序列,但其呼吸伪影要比FIESTA序列明显,而对于液体的显示FIESTA要优于SSFSE。结论:SSFSE序列和FIESTA序列对胎儿的不同组织其显示能力不同,所以根据病情做出不同的选择是非常重要的。     

Two-dimensional coronary MRA: limitations and artifacts

Our purpose was to assess image quality and interpretation problems of two-dimensional (2D) coronary MR angiograms. The coronary arteries of 27 subjects (12 normal volunteers and 15 patients) were evaluated with 2D coronary MR angiography (MRA). Coronary MRA was performed with a fat-suppressed electrocardiographically gated breath-hold gradient-echo sequence with k-space segmentation using a 1.5-T imager. Image quality throughout the study was occasionally degraded by: image ghosting (22%), ringing (19%), and/or blurring (22%) and incomplete fat-suppression (19%). Intermittent difficulties with breathholding were encountered in 44% of subjects. When limiting the analysis to those images with optimal image quality, interpretative difficulties were sometimes found: misregistration due to inconsistent breathholding (37%); difficulty in distinguishing veins from arteries (37%); obscured anatomy due to overlapping structures (26%); and poor visualization of portions of the left main coronary artery (59%). Two-dimensional coronary MRA studies have image quality and interpretive problems which need to be understood and addressed before routine clinical scanning is initiated.Correspondence to: A. J. Duerinckx