Non-Ischemic Perfusion Defects due to Delayed Arrival of Contrast Material on Stress Perfusion Cardiac Magnetic Resonance Imaging after Coronary Artery Bypass Graft Surgery

Herein we report about the adenosine stress perfusion MR imaging findings of a 50-year-old man who exhibited two different perfusion defects resulting from two different mechanisms after a coronary artery bypass surgery. An invasive coronary angiography confirmed that one perfusion defect at the mid-anterior wall resulted from an ischemia due to graft stenosis. However, no stenosis was detected on the graft responsible for the mid-inferior wall showing the other perfusion defect. It was assumed that the perfusion defect at the mid-inferior wall resulted from delayed perfusion owing to the long pathway of the bypass graft. The semiquantitative analysis of corrected signal-time curves supported our speculation, demonstrating that the rest-to-stress ratio index of the maximal slope of the myocardial territory in question was similar to those of normal myocardium, whereas that of myocardium with the stenotic graft showed a typical ischemic pattern. A delayed perfusion during long graft pathway in a post-bypass graft patient can mimick a true perfusion defect on myocardial stress MR imaging. Radiologists should be aware of this knowledge to avoid misinterpretation of graft and myocardial status in post bypass surgery patients.     

64层CT冠状动脉造影和磁共振多技术扫描联合诊断冠心病

目的：探讨64层螺旋CT冠状动脉造影（CTA）和磁共振心脏多技术扫描联合诊断冠心病（CHD）的临床应用价值。材料和方法：28例拟行冠状动脉造影（CAG）的冠心病患者，于术前1周分别完成64层螺旋CTA及磁共振心脏多技术扫描，以CAG为标准分析CTA与MRI诊断冠心病的各项指标，评价平行试验和系列试验的诊断价值。结果：64层螺旋CTA判断中、重度狭窄血管（≥50％）的敏感度、特异度、准确度、阳性预测值、阴性预测值为87．88％、98．73％、95．54％、96．67％、95．12％。磁共振多技术扫描左室增大8例，室壁明显变薄7例。在476个节段中，29个节段（6．09％）运动减弱或不运动，9个节段（1．89％）出现矛盾运动或室壁瘤。左心功能改变，与正常值相比有统计学意义（P〈0．001）。MRI间接推断中、重度狭窄血管（≥50％）的敏感度、特异度、准确度、阳性预测值、阴性预测值为93．75％、86．54％、89．29％、81．08％、95．74％。两种方法联合平行试验和系列试验总的敏感度、特异度分别为99．24％、85．44％，82．39％、99．83％。结论：64层螺旋CTA和磁共振心脏多技术扫描诊断冠心病各有优势，两者互相补充，联合使用可方便、全面、准确、无创地对冠心病患者进行评估。     

Myocardial Contrast Defect Associated with Thrombotic Coronary Occlusion: Pre-Autopsy Diagnosis of a Cardiac Death with Post-Mortem CT Angiography

We report the case of a female who died of suspected acute myocardial infarction. Post-mortem CT angiography (PMCTA) was performed with intravascular contrast infusion before the standard autopsy, and it successfully demonstrated the complete thrombotic occlusion of a coronary artery and also a corresponding perfusion defect on myocardium. We herein describe the PMCTA findings of a cardiac death with special emphasis on the potential benefits of this novel CT technique in forensic practice.     

Anomalous Origin of the Coronary Artery from the Pulmonary Artery in Children and Adults: A Pictorial Review of Cardiac Imaging Findings

Anomalous origin of the coronary artery from the pulmonary artery is a rare and potentially fatal congenital heart defect. Up to 90% of infants with an anomaly involving the left coronary artery die within the first year of life if left untreated. Patients who survive beyond infancy are at risk of sudden cardiac death. Cardiac CT and MRI are increasingly being used for the accurate diagnosis of this anomaly for prompt surgical restoration of the dual coronary artery system. Moreover, life-long imaging surveillance after surgery is necessary for these patients. In this pictorial review, multimodal cardiac imaging findings of this rare and potentially fatal coronary artery anomaly are comprehensively discussed, and representative images are provided to facilitate the understanding of this anomaly.     

Abolition of Respiratory-Motion Artifact in Computed Tomography Coronary Angiography with Ultrafast Examinations: A Comparison Between 64-row and 320-row Multidetector Scanners

Purpose

To compare the incidence of respiratory artifact in computed tomography (CT) coronary angiography performed with 64-row and 320-row multidetector scanners and to assess its effect on coronary evaluability.

Methods

A retrospective review of consecutive coronary angiograms performed on a 64-row multidetector CT from March to April 2007 (group 1: 115 patients, 63 men; mean age [standard deviation] 59.6 ± 12.8 years) and on a 320-row multidetector CT from March to April 2008 (group 2: 169 patients, 89 men; mean [SD] age 57.9 ± 11.6 years). Two cardiac radiologists assessed the occurrence of respiratory artifact and coronary evaluability in studies with respiratory artifacts. Unevaluable coronary segments because of motion at the same anatomical level of the respiratory artifact were considered unevaluable because of this artifact. The association between the occurrence of respiratory artifact and patient biometrics, medication, and scan parameters was examined.

Results

Respiratory artifacts were detected in 9 of the 115 patients from group 1 (7.8%) and in none of the 169 patients from group 2 (P < .001). Group 1 had longer scan times (median, 9.3 seconds; range, 7.5−14.4 seconds) compared with group 2 (median, 1.5 seconds; range, 1.1−3.5 seconds; P < .001). In group 1, 4 patients (3.5%) showed unevaluable coronary segments because of respiratory artifacts, and the CT coronary angiography was repeated in 1 patient (0.9%).

Conclusions

Respiratory artifacts are important in CT coronary angiography performed with 64-row multidetector scanners and impair the diagnostic utility of the examination in up to 3.5% of the studies. These artifacts can be virtually eliminated with a faster scan time provided by 320-row multidetector CT.     

Evaluation of the Ostium in Anomalous Origin of the Right Coronary Artery with an Interarterial Course Using Dynamic Cardiac CT and Implications of Ostial Findings

ObjectiveWe aimed to evaluate the ostium of right coronary artery of anomalous origin from the left coronary sinus (AORL) with an interarterial course throughout the cardiac cycle on CT and analyze the clinical significance of the ostial findings.Materials and MethodsFrom January 2011 to December 2015, 68 patients (41 male, 57.3 ± 12.1 years) with AORL with an interarterial course and retrospective cardiac CT data were included. AORL was classified as high or low ostial location based on the pulmonary annulus in the diastolic and systolic phases on cardiac CT. In addition, the height, width, height/width ratio, area, and angle of the ostium were measured in both cardiac phases. After cardiac CT, patients were followed until December 31, 2020 for major adverse cardiac events (MACE). Clinical and CT characteristics associated with MACE were explored using Cox regression analysis.ResultsDuring a median follow-up period of 2071 days (interquartile range, 1180.5–2747.3 days), 13 patients experienced MACE (19.1%, 13/68). Seven (10.3%, 7/68) had the ostial location change from high in the diastolic phase to low in the systolic phase. In the univariable analysis, younger age (hazard ratio [HR] = 0.918, p < 0.001), high ostial location (HR = 4.008, p = 0.036), larger height/width ratio (HR = 5.621, p = 0.049), and smaller ostial angle (HR = 0.846, p = 0.048) in the systolic phase were significant predictors of MACE. In multivariable cox regression analysis, younger age (adjusted HR = 0.917, p = 0.002) and high ostial location in the systolic phase (adjusted HR = 4.345, p = 0.026) were independent predictors of MACE.ConclusionThe ostial location of AORL with an interarterial course can change during the cardiac cycle, and high ostial location in the systolic phase was an independent predictor of MACE.     

Magnetic Resonance Imaging of Acute Reperfused Myocardial Infarction: Intraindividual Comparison of ECIII-60 and Gd-DTPA in a Swine Model

Purpose To compare a necrosis-avid contrast agent (NACA) bis-Gd-DTPA-pamoic acid derivative (ECIII-60) after intracoronary delivery with an extracellular agent Gd-DTPA after intravenous injection on magnetic resonance imaging (MRI) in a swine model of acute reperfused myocardial infarction (MI). Methods Eight pigs underwent 90 min of transcatheter coronary balloon occlusion and 60 min of reperfusion. After intravenous injection of Gd-DTPA at a dose of 0.2 mmol/kg, all pigs were scanned with T1-weighted MRI until the delayed enhancement of MI disappeared. Then they were intracoronarily infused with ECIII-60 at 0.0025 mmol/kg and imaged for 5 hr. Signal intensity, infarct-over-normal contrast ratio and relative infarct size were quantified, compared, and correlated with the results of postmortem MRI and triphenyltetrazolium chloride (TTC) histochemical staining. Results A contrast ratio over 3.0 was induced by both Gd-DTPA and ECIII-60. However, while the delayed enhancement with Gd-DTPA virtually vanished in 1 hr, ECIII-60 at an 80× smaller dose depicted the MI accurately over 5 hr as proven by ex vivo MRI and TTC staining. Conclusion Both Gd-DTPA and ECIII-60 strongly enhanced acute MI. Comparing with fading contrast in a narrow time window with intravenous Gd-DTPA, intracoronary ECIII-60 persistently demarcated the acute MI, indicating a potential method for postprocedural assessment of myocardial viability after coronary interventions.     

Artificial Luminal Narrowing on Contrast-Enhanced Magnetic Resonance Angiograms on an Occasion of Stent-Assisted Coiling of Intracranial Aneurysm: In Vitro Comparison Using Two Different Stents with Variable Imaging Parameters

ObjectiveIntracranial stenting for stent-assisted coiling of aneurysms requires adequate follow-up imaging. The aim of this in vitro study was to compare in-stent artificial luminal narrowing on contrast-enhanced MR angiograms (CE-MRA) when applying Neuroform® and Enterprise® stents for stent-assisted coiling.ResultsLower magnetic field strength, axial plane perpendicular to axis of stent, and wider bandwidth resulted in a lower ALN on CE-MRA for both stents. Larger voxel size resulted in lower ALN for Neuroform® stent. The parallel imaging acceleration factor did not affect ALN. The mean ALN was lower for Neuroform®, but it was not significant by a paired t test.ConclusionCE-MRA of the stented lumen of vascular phantom was partially impaired with ALN. Consequently, image plane orientation, magnetic field strength, bandwidth, and voxel size should be adjusted appropriately to reduce ALN.     

Left Ventricular Remodeling in Patients with Primary Aldosteronism: A Prospective Cardiac Magnetic Resonance Imaging Study

ObjectiveThis study used cardiac magnetic resonance imaging (MRI) to compare the characteristics of left ventricular remodeling in patients with primary aldosteronism (PA) with those of patients with essential hypertension (EH) and healthy controls (HCs).Materials and MethodsThis prospective study enrolled 35 patients with PA, in addition to 35 age- and sex-matched patients with EH, and 35 age- and sex-matched HCs, all of whom underwent comprehensive clinical and cardiac MRI examinations. The analysis of variance was used to detect the differences in the characteristics of left ventricular remodeling among the three groups. Univariable and multivariable linear regression analyses were used to determine the relationships between left ventricular remodeling and the physiological variables.ResultsThe left ventricular end-diastolic volume index (EDVi) (mean ± standard deviation [SD]: 85.1 ± 13.0 mL/m² for PA, 75.9 ± 14.3 mL/m² for EH, and 77.3 ± 12.8 mL/m² for HC; p = 0.010), left ventricular end-systolic volume index (ESVi) (mean ± SD: 35.2 ± 9.8 mL/m² for PA, 30.7 ± 8.1 mL/m² for EH, and 29.5 ± 7.0 mL/m² for HC; p = 0.013), left ventricular mass index (mean ± SD: 65.8 ± 16.5 g/m² for PA, 56.9 ± 12.1 g/m² for EH, and 44.1 ± 8.9 g/m² for HC; p < 0.001), and native T1 (mean ± SD: 1224 ± 39 ms for PA, 1201 ± 47 ms for EH, and 1200 ± 44 ms for HC; p = 0.041) values were higher in the PA group compared to the EH and HC groups. Multivariable linear regression demonstrated that log (plasma aldosterone-to-renin ratio) was independently correlated with EDVi and ESVi. Plasma aldosterone was independently correlated with native T1.ConclusionPatients with PA showed a greater degree of ventricular hypertrophy and enlargement, as well as myocardial fibrosis, compared to those with EH. Cardiac MRI T1 mapping can detect left ventricular myocardial fibrosis in patients with PA.     

心率对64层螺旋CT冠状动脉成像图像质量的影响

目的:评价心率对64层螺旋CT冠状动脉成像图像质量的影响.方法:采用GE Light speed 64层螺旋VCT,以心脏扫描模式对心脏动态体模进行扫描.心脏动态体模由3个部分组成:动力部分、解剖结构模拟部分和控制部分.心脏动态体模的心率设置为40、45、50、55、60、65、70、75、80、85、90、95、100、105、110和115次/min,心律齐.以球管转速0.35 s对不同心率下的心脏动态体模进行冠状动脉成像扫描.所有扫描数据在R-R间期90%时相分别进行单扇区和多扇区重建.重建数据传至工作站后处理成像.后处理方法采用VR、MPR重组模式.分别对重建图像进行评分.结果:①心率与图像质量呈负相关(P＜0.01);随着心率的增加,图像质量评分呈下降趋势;②在同一条件下多扇区重建算法较单扇区重建算法提高了图像质量评分.结论:采用心脏动态体模评价心率对64层螺旋CT冠状动脉成像图像质量的影响,对临床研究和应用有着重要价值.     

核素心肌灌注显像结合冠状动脉CT成像评价2型糖尿病功能相关冠状动脉病变的价值

目的 应用核素心肌灌注显像(MPI)结合冠状动脉CT成像(CTCA)评价2型糖尿病冠状动脉病变对心肌血供的影响,并与单一MPI或CTCA进行比较.资料与方法 纳入120例怀疑或确诊的冠状动脉粥样硬化性心脏病患者,根据其病史分为糖尿病组(n=58)和非糖尿病组(n=62),所有患者均行常规腺苷负荷/静息MPI和CTCA,并均于1个月内行冠状动脉血管造影术(CAG).以CAG、CAG联合MPI作为标准评价单一MPI、CTCA、MPI结合CTCA对“功能相关冠状动脉病变”的诊断效能.结果 糖尿病组MPI结合CTCA评价2型糖尿病冠状动脉病变与心肌血供关系的敏感性、特异性、准确性、阳性预测值和阴性预测值分别为93.58％、86.15％、90.80％、91.89％、88.89％.非糖尿病组MPI结合CTCA评价冠状动脉病变与心肌血供关系的敏感性、特异性、准确性、阳性预测值和阴性预测值分别为93.10％、91.43％、92.47％、94.74％、88.89％,均高于单一MPI或CTCA的诊断效能.结论 MPI结合CTCA评价2型塘尿病冠状动脉病变对心肌血供的影响,其诊断“功能相关冠状动脉病变”的效能明显高于单一影像技术.     

猪急性心肌梗死模型cTnI与DE-MRI相关性实验研究

目的探讨临床试剂盒是否适用于猪心肌梗死模型心肌肌钙蛋白(cTnI)的检测,其检测的cTnI峰值与DE-MRI所检测心肌梗死积分的关系。材料与方法 10只制备成功的猪急性心肌梗死模型分别于术前、术后1h、2h、5h、24h、48h、72h、1周采血行cTnI检测,所用试剂盒为临床试剂盒;术后行延迟增强MRI(DE-MRI)检查,心脏标本行氯化三苯基四氮唑(TTC)染色和免疫组织化学检查。结果 10例TTC染色和免疫组织化学均证实有心肌梗死;10例cTnI术后1h可见上升,于24h达高峰,24h峰值与DE-MRI、TTC检测的心肌梗死积分高度相关,相关系数分别为0.84、0.855(P值<0.05),有显著统计学意义。结论临床试剂盒对猪血清cTnI术前及术后检测,可反映猪心肌损伤;其24h峰值与DE-MRI心肌梗死范围强相关;两者均可活体内检测,且对坏死心肌有高度敏感性,两者结合有助于结果的相互印证和互为补充,可更准确地评价心肌梗死。     

Effect of Arterial Deprivation on Growing Femoral Epiphysis: Quantitative Magnetic Resonance Imaging Using a Piglet Model

Objective

To investigate the usefulness of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion MRI for the evaluation of femoral head ischemia.

Materials and Methods

Unilateral femoral head ischemia was induced by selective embolization of the medial circumflex femoral artery in 10 piglets. All MRIs were performed immediately (1 hour) and after embolization (1, 2, and 4 weeks). Apparent diffusion coefficients (ADCs) were calculated for the femoral head. The estimated pharmacokinetic parameters (Kep and Ve from two-compartment model) and semi-quantitative parameters including peak enhancement, time-to-peak (TTP), and contrast washout were evaluated.

Results

The epiphyseal ADC values of the ischemic hip decreased immediately (1 hour) after embolization. However, they increased rapidly at 1 week after embolization and remained elevated until 4 weeks after embolization. Perfusion MRI of ischemic hips showed decreased epiphyseal perfusion with decreased Kep immediately after embolization. Signal intensity-time curves showed delayed TTP with limited contrast washout immediately post-embolization. At 1-2 weeks after embolization, spontaneous reperfusion was observed in ischemic epiphyses. The change of ADC (p = 0.043) and Kep (p = 0.043) were significantly different between immediate (1 hour) after embolization and 1 week post-embolization.

Conclusion

Diffusion MRI and pharmacokinetic model obtained from the DCE-MRI are useful in depicting early changes of perfusion and tissue damage using the model of femoral head ischemia in skeletally immature piglets.     

Vulnerable Atherosclerotic Carotid Plaque Evaluation by Ultrasound,Computed Tomography Angiography,and Magnetic Resonance Imaging: An Overview

Ischemic syndromes associated with carotid atherosclerotic disease are often related to plaque rupture. The benefit of endarterectomy for high-grade carotid stenosis in symptomatic patients has been established. However, in asymptomatic patients, the benefit of endarterectomy remains equivocal. Current research seeks to risk stratify asymptomatic patients by characterizing vulnerable, rupture-prone atherosclerotic plaques. Plaque composition, biology, and biomechanics are studied by noninvasive imaging techniques such as magnetic resonance imaging, computed tomography, ultrasound, and ultrasound elastography. These techniques are at a developmental stage and have yet to be used in clinical practice. This review will describe noninvasive techniques in ultrasound, magnetic resonance imaging, and computed tomography imaging modalities used to characterize atherosclerotic plaque, and will discuss their potential clinical applications, benefits, and drawbacks.     

衰减伪影对冠心病患者门控心肌灌注显像图像质量及灌注结果的影响

目的探讨衰减伪影对冠心病患者门控心肌灌注显像(GMPI)图像质量及灌注结果的影响。资料与方法回顾性分析2020年3月—2021年3月在郑州大学第一附属医院核医学科经冠状动脉造影证实且于造影前后1周行GMPI的99例冠心病患者的图像,定性及半定量分析衰减校正前后GMPI图像结果,比较衰减校正前后左心室各壁段平均放射性计数及灌注结果的差异,进一步分析衰减校正前后灌注结果不一致部分的受检者的节段性室壁运动及增厚情况。结果与衰减校正前比较,衰减校正后左心室间隔、下后壁及侧壁的平均放射性计数较高(Z=-7.302、-8.014、-3.991,P均<0.001),心尖部较低(Z=-8.021,P<0.001)。其中女性衰减校正后前壁平均放射性计数减低(Z=-2.314,P=0.021)。男性衰减校正前后下后壁放射性计数差值明显高于女性(t=-8.408,P<0.05)。衰减校正后44%(44/99)的左前降支及37%(37/99)的右冠状动脉分支供血区域显像结果发生改变,结合超声心动图及GMPI结果显示其中85%(35/41)的左前降支及81%(29/36)的右冠状动脉分支供血区...