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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

30 patients with myocardial infarction older than three weeks were examined by MRI prior and following intravenous injection of 0.1-0.2 mmol/kg Gd-DTPA, 201TL-SPECT and cineventriculography. Gd-DTPA did not cause any significant change (p less than 0.05) of T2-values for infarcted or non-infarcted myocardium. Compared with this, signal intensity for T1-weighted images increased after the application of the contrast agent both for normal (26 +/- 14%) and infarcted myocardium (33 +/- 16%). The intraindividual signal intensity ratio for infarcted and normal myocardium increased from 1.06 +/- 0.07 to 1.12 +/- 0.09 after the injection of Gd-DTPA. The diagnosis of myocardial infarction by visual analysis of signal intensity was not possible in individual cases. Myocardial infarction could only be visualized indirectly by morphological changes such as wall thinning and aneurysm.
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PMID:[Gd-DTPA in magnetic resonance diagnosis of chronic myocardial infarct]. 302 53

Imagery by magnetic resonance (IMR) represents a new modality of medical imagery based on the interaction between the magnetic fields produced by radio-frequency waves and living substance. IMR finds an interesting application in the study of different stages of myocardial infarction. In 30 cases of myocardial infarction IMR was compared with thallium tomoscintigraphy and echocardiography. In the acute stage, myomalacia appears in IMR as a superbrilliant zone, and in the chronic stage parietal thinning and dyskinesias are apparent. Intraventricular thromboses, but also hemostasis in aneurysmatic or akinetic sites are visualised as a high-intensity signal within these areas. IMR represents therefore a new means of evaluation of size and evolution of the necrosis. This procedure provides also functional informations about the contraction and flow anomalies.
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PMID:[Importance of magnetic resonance imaging in myocardial infarct]. 309 74

Infarct expansion, regional dilation and thinning of the infarct zone, occurs within 1 day after myocardial infarction. Whether the early change in regional shape of infarct expansion affects the architecture of remote normal regions is unknown. To study this question, 45 rats with a transmural infarct were killed at 1, 2 and 3 days after infarction and their hearts were examined for infarct size and extent of expansion. Wall thickness and radius of curvature were measured within, adjacent to and remote from the infarct zone. Equivalent regions were analyzed in eight control hearts. The extent of disproportionate wall thinning and increased radius of curvature within the infarct zone of hearts with expansion was not dependent on infarct size. Significant wall thinning and increased regional radius of curvature were also seen in adjacent and remote regions of the hearts with expansion (p less than 0.001). These structural changes outside of the infarct occurred independent of infarct age and size, and were not seen in hearts without infarct expansion. Thus, when disproportionate thinning and dilation occur in the infarct region, they are accompanied by a distortion in shape of the entire heart including remote normal myocardium. This remote remodeling of noninfarcted myocardium correlates with extent of expansion, but not with age or size of the infarct.
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PMID:Global cardiac remodeling after acute myocardial infarction: a study in the rat model. 315 87

An attempt was made to examine left ventricular wall thickness and wall motion using two-dimensional echocardiography from the acute phase to 1 month after onset of myocardial infarction. Motion abnormalities and thinning of the wall were observed from immediately after the onset. Few areas that were akinetic or dyskinetic and had a wall thickness of 7 mm or less during the acute phase showed improvements in wall motion 1 month later. However, some areas with a wall thickness of 8 mm or more did reveal improved wall motion even if they were akinetic or dyskinetic during the acute phase. Since the akinetic or dyskinetic areas with a wall thickness of 7 mm or less during the acute phase demonstrated a positive correlation with the peak CPK and nQ, and a negative correlation with the left ventricular ejection fraction 1 month after the onset, they were considered to be necrotic zones of myocardial infarction. The area of abnormal wall motion, on the other hand, was considered to correspond to a wider area including the ischemic as well as the necrotic zones. Evaluation of the necrotic and ischemic areas of infarction separately from the acute phase appears to be useful not only for the selection of treatment during the acute phase but also for predicting the cardiac function 1 month later and for determining the time of initiation and method of cardiac rehabilitation.
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PMID:Two-dimensional echocardiography in acute myocardial infarction--relationship between left ventricular wall thickness and wall motion abnormalities. 322 93

To determine the serial changes in T1 and T2 relaxation times of myocardial infarction, and their relationship to observed changes in water content, regional myocardial blood flow, and histopathology, rabbits were studied at 14 time intervals ranging from 30 min to 6 months after coronary artery ligation. All values were compared to a control group. Hearts were subdivided into infarct and normal segments for measurement of blood flow, water content, and relaxation times (20-MHz spectrometer); other hearts were excised intact for histopathologic studies. T1 relaxation time of infarcted myocardium did not change significantly compared to control over the 6-month study period. T2 relaxation time increased (P less than 0.0001) at 3 days and returned to baseline by 2 months. Consonant with the increase in T2 of infarct, nuclear magnetic resonance (NMR) images at 3 days demonstrated an increase in signal intensity of infarct compared to surrounding normal myocardium. At 6 months, marked myocardial thinning was observed without changes in signal intensity. Changes in T2 of infarcted myocardium were not related to changes in water content or severity of ischemia, but correlated best with infarct healing and scar formation as detected on histopathology. In conclusion, the findings of this study indicate that T2 relaxation time of the infarcted myocardium increases markedly at 3 days and remains elevated for 2 months. These changes correlate best with the onset and progression of infarct healing. These data demonstrate the potential of T2-weighted NMR imaging for assessing healing patterns following ischemic myocardial injury.
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PMID:Serial changes in nuclear magnetic resonance relaxation times after myocardial infarction in the rabbit: relationship to water content, severity of ischemia, and histopathology over a six-month period. 323 Oct 66

Proton NMR imaging of myocardial ischemia without infarction requires the use of paramagnetic contrast agents. Even during the first few hours of infarction, imaging without contrast enhancement reveals only slight natural image contrast. Myocardial infarction, however, is much more readily detected during the first few days and weeks post coronary occlusion; this is due to a marked elevation in T2 during this time period. Chronic infarction, several months after the acute event, does not demonstrate altered signal intensity, but can be detected by visualizing myocardial wall thinning and aneurysm formation. Information regarding high energy phosphate metabolism can be acquired in vivo in ischemic animal preparations; preliminary data has demonstrated that it is possible to acquire similar information noninvasively in man. Development of this technique will eventually permit the study of pharmacological and mechanical interventions aimed at preserving myocardium in the ischemic heart. Exogenous labelling of myocardial tissue with carbon-13 permits the study of the effects of substrates on cellular metabolism. Ultimately, the technique of chemical shift imaging will provide a method of spatially resolving valuable metabolic information in the form of an NMR image. Eventually, with the gradual development of NMR technology, imaging and spectroscopy will become truly important clinical tools in the investigation of ischemic heart disease in man.
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PMID:Evaluation of myocardial ischemia and infarction by nuclear magnetic resonance techniques. 328 14

This study assesses magnetic resonance (MR) imaging for the evaluation of both the functional and anatomic extent of damage to the left ventricle (LV) from myocardial infarction (MI). This was accomplished by blinded region-of-interest analysis of 36 MR examinations (orthogonal-transaxial, electrocardiographically-gated, multiphasic, single spin-echo) for determination of ejection fraction (EF) and relative MI volume (i.e., percent of total LV myocardial volume). Comparison of the results was then made with a measure of global residual LV function (i.e., score quotient or SQ) derived from segmental scoring of LV wall motion on a two-dimensional echocardiogram (Echo) and with an EF value from a left ventriculogram (LVG), both performed relatively concurrently with MR. Significant (p less than 0.01) overall correlations were noted between MR-EF and both Echo-SQ (r = 0.56) and LVG-EF (r = 0.78), and these relationships were relatively stronger when MI was located in the right coronary artery (RCA) than when it was found in the left anterior descending (LAD) distribution (e.g., MR-EF compared with LVG-EF: r = 0.87, p less than 0.05 for RCA; and r = 0.48, p = NS for LAD). The best expression of relative MI volume appeared to be based upon absolute volume of regionally-thinned LV wall multiplied by a correction factor for its residual contractility and then the addition of a volume correcting for the amount of regional wall thinning by necrosis (i.e., "total-Fxn" MI volume).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Estimation of the functional and anatomic extent of myocardial infarction using magnetic resonance imaging. 335 2

The authors describe their personal experience using Magnetic Resonance Imaging (MRI) in the evaluation of cardio-vascular diseases. MRI made it possible to obtain multiplanar anatomical images of the cardio-vascular system without X-rays and conventional contrast medium. MRI supplied with indirect flow evaluation, too. MRI was particularly useful in the assessment of congenital heart diseases, since it shows the heart chambers and the great vessels at the same time and in the different phases of cardiac revolution. MRI was also useful in the evaluation of many acquired heart diseases, such as myocardium diseases, valve diseases, myocardial ischemias, pericardium diseases. Moreover, MRI correctly showed aortic aneurysms. In all the 55 patients examined, it was possible to obtain a good definition of the cardiac structures, especially when "cardiac gating" was employed. In the 3 ventricular and in the 5 atrial defects, the dimensions of the defect and the dilatation of the involved cardiac chambers were precisely assessed. In the 6 aortic coarctations, MRI evaluated the level and the grade of the stenosis, with consequent definition of the anatomic type. Moreover, collateral circulation and dilatation before and/or after the stenosis were evident. In all the 7 complex cardiopathies examined (3 Fallot tetralogies, 1 Fallot pentalogy, 1 aortic cervical arch, and 2 Ebstein diseases) MRI demonstrated each single anomaly of the malformations, at both cardiac and vascular levels. In 2 patients with atrial fibrillation, MRI visualized endoatrial thrombi. In the 7 patients with previous myocardial infarction, the site of ischemia was depicted as a thinning of the wall, while the remaining myocardium appeared hypertrophic. MRI correctly demonstrated all thoracic aorta aneurysms, even in a case where both CT and angiography were negative, due to the aneurysm being thrombosed. Mural thrombi were evident with both MRI and CT, but not always visible with angiography. In the 5 dissected aneurysms, MRI--like CT--assessed the origin of the dissection, and the dimensions of the true and false lumen; moreover, it indirectly evaluated the slow and turbulent blood flow within the true lumen, and the presence of thrombi in the false lumen.
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PMID:[Use of magnetic resonance in the diagnosis of congenital and acquired cardiopathies. Preliminary note]. 337 87

To determine whether the extent of left ventricular dysfunction and the degree of shape distortion can predict outcome in survivors of moderate-sized anterior Q wave myocardial infarction who are undergoing exercise training, these variables were measured by two-dimensional echocardiography before and after 12 weeks of a low level exercise training program starting 15 weeks after infarction in 13 patients (7 in group 1 and 6 in group 2) and 12 weeks apart in 24 matched control patients without training. By the end of training, the functional class score had increased in group 2 (from 2.25 to 2.67, p less than 0.005) but had not changed in group 1. Further discrimination of groups 1 and 2 was provided by an initial asynergy (akinesia or dyskinesia, or both) less than 18% or greater than or equal to 18%. Compared with group 1, group 2 had greater initial asynergy (32 versus 6%, p less than 0.001), expansion index (asynergic/normal endocardial segment length: 1.8 versus 1.6, p less than 0.025) and peak shape distortion index (12.2 versus 1.0 mm, p less than 0.005) but lower ejection fraction (43 versus 59%, p less than 0.05) and thinning ratio (asynergic/normal wall thickness: 0.61 versus 0.74, p less than 0.05). These variables did not change with training in group 1. However, in group 2, training caused significant increase in asynergy (from 32 to 40%, p less than 0.05), expansion index (from 1.8 to 2.0, p less than 0.01) and peak shape distortion (from 12.2 to 20.9 mm, p less than 0.05) associated with a decrease in thinning ratio (from 0.61 to 0.51, p less than 0.001) and ejection fraction (from 43 to 30%, p less than 0.005). Initial values for these variables were similar for corresponding control groups but did not change over the 12 weeks. Thus, patients with greater than or equal to 18% left ventricular asynergy on the initial echocardiogram showed more shape distortion, expansion and thinning before exercise training and developed further functional and topographic deterioration with training.
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PMID:Exercise training after anterior Q wave myocardial infarction: importance of regional left ventricular function and topography. 276 17

To assess the usefulness of X-ray computed tomography (CT) and magnetic resonance imaging (MRI) in detecting and evaluating ischemic heart disease, conventional and enhanced CT were performed for 180 patients (150 with transmural infarction, 12 with subendocardial infarction, and 18 with angina pectoris). MRI examinations were performed for 38 patients (31 with transmural infarction, three with subendocardial infarction, and four with angina pectoris). With enhanced CT, two findings in the myocardium were direct evidence of myocardial infarction: 1. filling defects on the early scans, and 2. late enhancement of the myocardium on the delayed scans. The former were observed mainly at the sites of recent anterior myocardial infarction and the latter were seen in about half of the patients with recent and remote anterior myocardial infarctions. However, these findings were inadequately imaged in patients with inferoposterior infarction and subendocardial infarction. Among 137 patients with transmural infarction, enhanced CT revealed left ventricular aneurysms in 51 (37%) and ventricular thrombi in 26 (19%). ECG-gated MRI apparatus having a superconducting magnetic operating at 0.25 Tesla was used, and data for this study were collected using the single-slice spin echo technique. In eight of nine patients with acute myocardial infarction, gated MRI demonstrated the infarcted myocardium as regions of high signal intensity relative to that of the adjacent normal myocardium. Such a difference in MRI signal intensity was scarcely recognized in the chronic stage of myocardial infarction, but the indirect findings of infarction, such as regional wall thinning, wall motion disturbances, left ventricular aneurysms, and ventricular thrombi were easily detected using MRI. No characteristic finding was obtained by CT or MRI in patients with angina pectoris.
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PMID:[Diagnostic evaluation of ischemic heart disease by X-ray computed tomography and magnetic resonance imaging]. 342 26


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