American journal of cardiac imaging最新文献

Myocardial stunning is a recently described phenomenon in which myocardium subjected to short-lasted episodes of ischemia remains hypokinetic or even akinetic (stunned) after adequate flow is reestablished. Therefore, diagnostic technique that can assess regional perfusion could be of value in establishing this diagnosis. This postischemic abnormality in contractility can last minutes, hours, or days, but eventually recovers. Faster recovery of function occurs under inotropic stimulation, and this knowledge has been applied clinically to diagnose this entity, ie, with the use of dobutamine echocardiography. This article is a review of current literature on the use of dobutamine echocardiography and of myocardial contrast echocardiography, two techniques found to be useful in the diagnosis of myocardial stunning.

Coronary calcium screening using electron beam computed tomography (EBCT) is being applied clinically and for research purposes. We compared the accuracy of a specialized image analysis system with the standard proprietary software in the scanner's host computer. Sixty-seven symptomatic patients underwent coronary angiography and EBCT. Tomograms were analyzed using the proprietary software included in the scanner and with a specialized coronary calcium scoring work station. Sensitivities, specificities, and receiver operating characteristic curve areas were calculated for the proprietary software and the specialized system using the angiographic definition of disease of at least one stenosis causing greater than 50% luminal narrowing. There were no significant differences between the proprietary and the specialized software's accuracy. Receiver operating characteristic curve areas were 0.84 and 0.82 for proprietary software, respectively. During a 50 minute analysis session, the average number of studies analyzed were 12.6 +/- 1.7 using the proprietary software and 23.2 +/- 5.7 using the specialized software (P = .02).Image analysis was thus found to be more rapid using the specialized software. The specialized coronary calcium analysis system is as accurate as the proprietary software for scoring EBCT for coronary calcium. The reduction in analysis time makes the specialized system the preferable method.

The purpose of this study was to assess feasibility and safety in the diagnosis of coronary artery in the diagnosis of coronary artery disease and myocardial ischemia using adenosine triphosphate (ATP) stress echocardiography. ATP, a product of human myocardial tissue, is more potent than adenosine in increasing coronary blood flow. Like adenosine, ATP also has a short half-life (<10 s). Left ventricular echocardiograms were recorded during step-wise infusions of ATP in 86 patients who underwent coronary angiography and stress thallium 201 scintigraphy. No serious complications occurred with ATP infusion and most of the side effects were mild and transient. Significant coronary artery disease (>75% diameter stenosis) was present in 34 of 48 patients who had normal echocardiograms at rest. The sensitivity and specificity of ATP-induced wall motion abnormalities for coronary artery disease was 65% (22 of 34) and 100% (14 of 14), respectively. The sensitivity was 50% (10 of 20) in those with one-vessel disease and 86% (12 of 14) in those with multivessel disease (P < .05). In patients with normal echocardiograms at rest and without prior myocardial infarction, the sensitivity of ATP stress echocardiography for the detection of myocardial ischemia assessed by 201Tl single proton emission computed tomography was 58%, with a specificity of 76%, and a diagnostic accuracy of 66%. The sensitivity was 43% in those with one-vessel disease, and 86% in those with multivessel disease (P = .05). In patients with prior myocardial infarction, the sensitivity of ATP stress echocardiography for the detection of viable but jeopardized myocardium was 81%, with a specificity of 91%. The patients with well-developed collateral circulation had a higher incidence of developing wall motion abnormality than those without collaterals (70% v 40%, P < .01). ATP stress echocardiography is valuable for the assessment of coronary artery disease in patients with multivessel disease, coronary collaterals, and with prior myocardial infarction.

Coronary artery calcification is a recognized marker for coronary atherosclerosis; however, the relationship between calcification and the success of balloon angioplasty at a calcification site has not been determined. The purpose of this study was to evaluate whether the presence of coronary artery calcification, as detected by electron bean computed tomography (EBCT), was predictive of restenosis after percutaneous transluminal coronary angioplasty (PTCA). Site- specific coronary calcification was determined by EBCT in 20 patients with 24 lesions before, immediately after, and 2 to 18 month after PTCA. Calcification was scored using >130 Hounsfield units and >1.02-mm2 area criteria. Coronary calcium at the PTCA site was significantly greater in restenosed versus nonrestenosed patients (109.16 +/- 198.16 mm2 v 4.39 +/- 9.50 mm2) (P < .025). The amount of coronary calcium did not change as a result of the PTCA procedure (+2.72 +/- 22.31 mm2 v -4.81 +/- 7.82 mm2) (P = NS). The rate of progression of calcification was not greater in restenosed versus nonrestenosed patients (1.78 +/- 3.32 mm2/month v 0.09 +/- 0.19 mm2/mo) (P = NS). Site-specific coronary calcification as determined by EBCT appeared to be predictive of patients with an increased likelihood to restenose after PTCA. Further studies are needed to verify these observations in a considerably larger patient population.

Although the use of balloon dilation for treatment of native and recurrent coarctation of the aorta (coA) has become widespread, the optimal balloon size and postdilation vessel wall changes remain undetermined. Intravascular ultrasound (IVUS) imaging has emerged as a an important adjunct in the treatment and follow-up of patients with coronary artery and peripheral vascular lesions, and has been used for evaluation in a limited number of patients with CoA. We used a combination of balloon dilation/ultrasound imaging catheter in animals with experimentally-induced CoA. We used a combination balloon dilation/ultrasound imaging catheter in animals with experimentally-induced CoA . This technique provided real-time data regarding aortic wall morphology and luminal diameter during balloon angioplasty of the CoA. In humans, we used IVUS to study CoA before and after both transcatheter and surgical therapy. IVUS was more sensitive than angiography in the detection of intimal tears post-balloon dilation and in the evaluation of vessel wall changes and remodelling observed at follow-up after relief of CoA. IVUS may provide valuable information regarding vascular wall changes that predict aneurysm format ion, restenosis, or a successful result after balloon dilation.

Clinical cardiologists are now aware of several conditions in which myocardial function can be depressed in the absence of overt ischemia or infarction. Myocardial stunning refers to a particular situation in which the contractile state of the myocardium remains depressed after a brief period of ischemia and reperfusion. Positron emission tomography has been shown to be an important tool for identifying viability within stunned myocardium on the basis of enhanced fluorine 18-fluorodeoxyglucose (FDG) uptake relative to perfusion. This image pattern has been referred to as a ¿flow-metabolism mismatch¿ and is predictive of patients who would benefit from reperfusion therapies. This review highlights the importance of considering the time course of altered FDG uptake within regionally stunned myocardium.

Tree-dimensional (3-D) reconstruction of acquired tomographic images in adults has recently been described. With an adaptation of this technique, we performed 3-D reconstruction of transabdominal images of the abdominal aorta to test the hypotheses that 3-D reconstruction of the abdominal aorta is feasible and that 3-D images have incremental value over 2-D in the detection of atheromatous plaque. Twenty-one patients undergoing contrast aortography (Aogram) for clinical indications (1 abdominal aorta (AA) aneurysm, 5 peripheral vascular disease, 1 renal artery stenosis, 14 renal donors) were studied using a 5-MHz annular array probe fitted to a mechanical registration device. In 13 of 21 patients, adequate 2-D ultrasound slices were acquired around a 180 degrees rotation and stored as a volumetric data set using a dedicated computer and 3-D images were reconstructed off-line. Three-dimensional and planar images were blindly compared with Aograms using the following scale: grade 1, normal; grade 2, increased echodensity of the intimal surface; grade 3, local intimal thickening and/or luminal irregularity; and grade 4, protruding mass. Analogous 3-D images were produced in all 13 patients with branching vessels visible in 3 of 13. In 10 patients, the Aogram was interpreted as normal. Compared with Aogram, blindly interpreted 3-D images were compared and correctly identified normal AA in 8 of 10 and atherosclerotic plaque (grade 3 or 4) in 2 of 3. Discordant results were present in 2 of 10 normal aortas and 1 of 3 disease aortas. When 2-D (planar) images were compared with Aograms, 8 of 10 identified normal AA and 3 of 3 aortas with grade 3 or 4 plaque. Thus, in 2 patients, 3-D and planar images suggested atherosclerotic changes not seen by Aogram. Transabdominal 3-D imaging of the abdominal aorta is a feasible technique. Early data suggest that 3-D imaging may distinguish normal from moderate to severe disease, but currently has no demonstrable incremental value over conventional 2-D images. These early results in a small number of patients suggest that this promising technique warrants further evaluation.

A case of previously undiagnosed cervical carcinoma metastatic to the right ventricular cavity and the central and peripheral pulmonary arteries is presented. The usefulness of ultrafast computed tomography in comparison with echocardiography for the evaluation of suspected metastatic diseases to the heart and pulmonary arteries is discussed.

Intracoronary implantation of stent devices is a new interventional technique with a promising role in the treatment of acute coronary occlusions caused by intimal dissection and suboptimal results of percutaneous transluminal coronary angioplasty. However, the prolonged presence of stent material embedded in the arterial wall may generate unknown late consequences. Major complications consist of subacute to chronic occlusion and restenosis. To elucidate the underlying cause we removed an angiographically occluded intracoronary artery Palmaz-Schatz stent before coronary artery bypass grafting. Scanning electron microscopy showed thorough coating of the metal struts of the stent by normal neoendothelial cells. Side branches arising at the level of the stent were patent. According the specific angiographic feature thrombotic occlusion originated distally of the stent.