左冠状动脉右室瘘的X线和MRI诊断1例

病例男,18岁,活动后心悸、气短7年,伴紫绀,肺动脉第二音不清,左2～3肋间闻及双期杂音。X线表现:双肺血略少,心脏增大,以左室增大为主,肺动脉段不凸,相当于左三弓处见局限性结节状突出(图1),边缘清晰。MRI:心脏增大,右房、室增大,肺动脉干较细,房间隔信号中断约1.2cm,室间隔完整,左冠状动脉窦扩张,左冠状动脉增粗、迂曲走行,在横轴位像上似串珠样(图2),其③④图1心脏远达正位像。双肺血略少,心脏增大,以左室大为主,相当于左三弓处见局限性结节状突出,边缘清晰。图2MRI横轴位像。左冠状动脉窦明显扩张(有尾箭头),左冠状动脉迂曲、扩张(无尾…     

Spasm in ectatic coronary arteries

Patients with ectatic coronary arteries often have occlusion of the affected arteries. Because ectatic arteries are considered to have medial damage, they are normally assumed to have little capacity to constrict; therefore, spasm has not been considered a factor in the occlusive process. In two patients who had diffuse coronary ectasia, no appreciable stenosis, and angina pectoris, we found that the ectatic arteries indeed had an augmented vasoconstrictor response to ergonovine. This finding indicates that some ectatic arteries have a sufficient amount of smooth muscle to cause coronary spasm and may produce symptoms of coronary disease by causing recurrent arterial spasm.     

Spasm of organically altered coronary arteries

The paper is concerned with 11 patients with an angiographically recorded spasm at the site of the coronary artery stenosis. In the 2 patients, the spasm was spontaneous, whereas in the 9, it was provoked by ergometrine. None of the patients had a typical clinical picture of Prinzmetal's angina pectoris, but all the cases were characterized by exacerbation of coronary heart disease, which was manifested by repetition and increase of the intensity of attacks of angina pectoris at rest. The data of the repeated ergometrine tests, during which the ECG was recorded indicate that in the majority of the patients, the ability to respond by spasms toward ergometrine administration disappeared as the clinical condition was stabilized, but some of the patients preserved this ability despite therapy with calcium antagonists. If 2 or 3 coronary vessels were involved, spasm developed but in one of the vessels. This is indirect evidence for the fact that during multiple stenosing of the coronary arteries, the reactivity of one of the stenoses plays the leading part in the genesis of the disease exacerbation.     

Anomalous coronary arteries of aortic origin

Anomalous coronary arteries cause only uncharacteristic symptoms and are therefore often an incidental finding during conventional coronary angiography, with an incidence of 0.3-0.8%. The commonest anomaly is an aberrant origin of the main left or right coronary artery from the wrong sinus of Valsalva. Rarely there is a fistula draining into one of the cardiac cavities (right ventricle, right atrium, left ventricle or, rarely, superior vena cava) or displaced connection, as seen in anomalous origin of coronary artery from the pulmonary artery, resulting in a left-to-right shunt. In congenital heart disease, especially Fallot's tetralogy, the incidence of abnormal coronary arteries may be 2% or more. The proximal course in the former category may be misdiagnosed in up to 50% of cases. Aortic root injection with subtraction angiography, further detailed investigation with transoesophageal echocardiography or magnetic resonance angiography are therefore required as these have potential implications on subsequent surgery. Because of the abnormal course between aorta and pulmonary artery/outflow tract of the right ventricle and acute angulation there is a risk of angina, acute myocardial infarction or sudden death during or after exercise. It is therefore important to identify the exact cardiac anatomy, particularly in patients undergoing angioplasty, stenting or cardiac surgery.     

MRI of subclinical coronary atherosclerosis

Coronary artery disease (CAD) is the leading cause of morbidity and mortality in the Western world. Whereas atherosclerosis alone is rarely fatal, sudden luminal thrombosis precipitates life-threatening clinical events such as acute coronary syndromes and stroke. Plaques assumed to cause luminal thrombosis are referred to as vulnerable plaques, which tend to preserve a normal vessel lumen. Today’s clinical assessment of CAD is based on the severity of luminal narrowing or flow restriction and functional indices of cardiac ischemia, thus making a priori detection of vulnerable plaques ambiguous. MRI is an emerging noninvasive imaging modality and is unique in its ability to offer morphologic, functional, and biologic information, including several approaches to detect, quantify, and characterize atherosclerotic plaque burden and composition. These methods, which include noncontrast and contrast-enhanced vessel wall imaging, have shown great promise to assess morphological and biological characteristics of vulnerable plaques, such as inflammatory activity, neovasculature, or positive vessel wall remodeling. Current research that focuses on the development of novel contrast agents for the identification of biologic processes associated with plaque progression and plaque rupture ultimately may facilitate the detection of subclinical disease, enable earlier treatment, and allow imaging-based therapy control.     

Digital subtraction angiography of the coronary arteries

The application of digital coronary arteriography in the evaluation of patients with known or suspected coronary artery disease is considered. Digital imaging of coronary arteries and bypass grafts can augment 35-mm cineangiography and may eventually replace film for coronary arteriography. The clinical efficacy of both selective and nonselective digital coronary arteriography is not yet established, however, a number of advantages over 35 mm cine have now been delineated including high contrast sensitivity image subtraction and digital image processing. One particular advantage of digital coronary arteriography is the ability to perform an immediate quantitative analysis of coronary images providing a reliable and consistent measure of the significance of a stenotic lesion. Technical requirements for digital coronary arteriography include a high output X-ray generator, low noise television chain, a 512 X 512 digital image matrix, frame rates of at least 15 fps, and high data storage capacity of c500 megabytes. The utilization of digital coronary imaging as a supplement or in place of 35-mm cine angiography will provide improved coronary imaging and enable quantification for more accurate and clinically significant coronary artery imaging.     

Dimensions of the coronary arteries in children

The extent of narrowing of the coronary arteries was measured in a series of 106 children who died accidentally. The outer radius of left main stem coronary artery increases from 1.06 mm at the age of 1 to 1.67 mm at 15. The left anterior descending branch increased with age from 0.70 to 1.35 mm and the inner radius from 0.55 to 1.10 mm. The mean thickness of the media and intima also increased with age; the correlation between thickness and weight was less pronounced. The coronary arteries thickened concomitantly with the size of the artery but that was due mainly to thickening of the intima. Substantial narrowing was found in the youngest age groups and the extent did not correlate with age but with the size of the vessel. The greatest narrowing was 57% of the arterial lumen. The measured dimensions will serve as normal values for the coronary arteries in Finnish children at autopsy.     

冠状动脉粥样硬化的高分辨磁共振管壁成像

目的探讨高分辨MR管壁成像显示冠心病冠状动脉管壁异常的可行性。方法收集18例经冠状动脉血管造影或CT血管成像证实有冠状动脉狭窄的冠心病患者,在1.5 T MR设备中进行冠状动脉管壁黑血成像。采集狭窄段及其邻近非狭窄段的横断面管壁图像,由两位MR医师协商评估,将显示不满意的图像剔除。在显示满意的狭窄段和非狭窄段管壁图像上分别其测量管壁厚度、管腔直径及横截面积并进行对比。结果 18例患者中有15例患者顺利完成检查,经冠状动脉造影或CT血管成像证实共有26个冠状动脉狭窄段,MR管壁成像共获得显示满意的图像34幅(狭窄段和非狭窄段各17幅),与非狭窄段相比,狭窄段管壁明显增厚(P0.01),管腔直径及横截面积明显减小(P0.05),差异均具有统计学意义。在MR管壁图像上,冠状动脉狭窄段的管壁呈局限性增厚者11例(64.7%),呈弥漫性增厚者6例(35.3%)。增厚的管壁呈高信号者4例(23.5%),等信号者5例(29.4%),低信号者1例(5.9%),高低混杂信号者7例(41.2%)。结论高分辨MR冠状动脉管壁成像可显示粥样硬化的冠状动脉狭窄段管壁及管腔异常,为冠心病的诊断提供了有力的影像证据,是一种很有潜力的检查方法。     

The no-reflow phenomenon in coronary arteries

No reflow occurs when there is inadequate myocardial perfusion of a given segment of the coronary circulation without evidence of epicardial vessel obstruction. It is a rare but clinically significant condition associated with myocardial infarction and coronary interventions. Diagnosis is usually based on clinical signs of myocardial ischemia (symptoms and/or ECG changes) combined with coronary angiography. Management can be difficult and primarily consists of intracoronary administration of vasodilators. One interesting etiology is thromboembolism and this has become the focus for new potential treatments, including distal embolic protection devices.     

Automatic centerline extraction of coronary arteries in coronary computed tomographic angiography

Coronary computed tomographic angiography (CCTA) is a non-invasive imaging modality for the visualization of the heart and coronary arteries. To fully exploit the potential of the CCTA datasets and apply it in clinical practice, an automated coronary artery extraction approach is needed. The purpose of this paper is to present and validate a fully automatic centerline extraction algorithm for coronary arteries in CCTA images. The algorithm is based on an improved version of Frangi's vesselness filter which removes unwanted step-edge responses at the boundaries of the cardiac chambers. Building upon this new vesselness filter, the coronary artery extraction pipeline extracts the centerlines of main branches as well as side-branches automatically. This algorithm was first evaluated with a standardized evaluation framework named Rotterdam Coronary Artery Algorithm Evaluation Framework used in the MICCAI Coronary Artery Tracking challenge 2008 (CAT08). It includes 128 reference centerlines which were manually delineated. The average overlap and accuracy measures of our method were 93.7% and 0.30 mm, respectively, which ranked at the 1st and 3rd place compared to five other automatic methods presented in the CAT08. Secondly, in 50 clinical datasets, a total of 100 reference centerlines were generated from lumen contours in the transversal planes which were manually corrected by an expert from the cardiology department. In this evaluation, the average overlap and accuracy were 96.1% and 0.33 mm, respectively. The entire processing time for one dataset is less than 2 min on a standard desktop computer. In conclusion, our newly developed automatic approach can extract coronary arteries in CCTA images with excellent performances in extraction ability and accuracy.     

Volumetric intravascular ultrasound measurements in coronary arteries

Editorial Commentary

Volumetric intravascular ultrasound measurements in coronary artries     

Drug-eluting stents to prevent reblockage of coronary arteries

Restenosis limits the success of percutaneous transluminal coronary interventions. Coronary artery stenting decreases restenosis, improves outcomes, and is currently the most commonly used percutaneous coronary intervention in the United States. However, in-stent restenosis continues to occur at an unacceptable rate. In-stent restenosis is a neointimal hyperplastic response resulting primarily from vascular smooth muscle cell proliferation. Treatment with anti-proliferative agents presents a logical approach to eradicating restenosis, however, these drugs are highly toxic. Coating stents with anti-proliferative agents allows local delivery of high doses and avoids systemic side effects. In 2001, the results of two clinical trials, RAVEL and ELUTES, using sirolimus- and paclitaxil-coated stents demonstrated nearly complete elimination of in-stent restenosis. These dramatic results represent a tremendous advance in the treatment of coronary heart disease.     

Digital subtraction angiographic assessment of the coronary arteries and coronary flow reserve

Although intravenous digital subtraction angiography was originally intended as a means of performing lessinvasive peripheral angiography, this less invasive approach has not proven feasible for coronary artery studies. Digital imaging has, however, proven helpful for the immediate replay, enhancement and quantification of coronary arteriography and enables the performance of regional blood flow (coronary flow reserve) analysis. Flow analysis is clinically helpful in determining the hemodynamic significance of individual coronary stenoses, which cannot always be assessed even using quantitative stenosis measurements. One method of assessing flow reserve by digital means uses parametric images to display the timing (color coded) and density (intensity coded) of the contrast bolus as it transverses the regional myocardial circulation. Analysis of baseline and hyperemic condition parametric images provides quantitative regional flow reserve information.     

冠状动脉多层CT血管造影发展现状

冠状动脉疾患是严重危害人类身心健康并危及生命的疾病之一，其发病率呈逐年上升趋势。迄今为止，冠心病诊断的金标准仍为选择性冠状动脉造影（CAG），这是一种具有发生潜在严重并发症（如心律不齐、心肌梗塞、冠脉离断或死亡等）危险的有创性检查，且费用昂贵，患者常难以接受，所以仅在有较为严重的临床指征时才被应用。近年来，许多研究者应用MRI及EBCT进行冠状动脉成像的研究，取得了一定的成果，但是二者均有一定的局限性犤１－３犦。１９９８年多层CT（Multi－SliceCT）问世，这种拥有多排探测器及锥形扫描线束的CT机可实现亚…