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Biomedical subjects

F M Prigent

Publications and source records attributed to F M Prigent.

11 recordsLinked to original sources
PubMed2000

Interventional therapy in heart failure management.

The incidence and prevalence of congestive heart failure are rapidly increasing because of the progressive decrease in age-adjusted mortality rates for coronary artery disease and hypertensive heart disease, together with the progressive aging of the US population. Despite great advances in maximal medical therapy, most patients with symptomatic congestive heart failure can expect functional impairment, interludes of worsening symptomatology, and a shortened life span. Thus, it is appropriate to ask whether the interventional revolution that is under way for the management of ischemic cardiovascular disease can be applied with benefit to the management of congestive heart failure. The use of interventional therapies for the treatment of elderly patients with congestive heart failure caused by coronary artery disease, valvular heart disease, or renal vascular disease is addressed.

Aged↗
PubMed1997

Clinical value of electron-beam computed tomography in the diagnosis and prognosis of coronary artery disease.

Electron-beam computed tomography (EBCT) is a relatively new imaging modality that provides transaxial cardiac images with excellent spatial and temporal resolution. At present EBCT is used primarily to detect and quantify the extent of coronary calcification. In autopsy studies, increasing areas of classification are associated with the increasing likelihood of more advanced atherosclerosis, but the relationship is not linear, with large confidence limits, and EBCT may underestimate the total plaque burden. Compared with angiography, EBCT has a high sensitivity to detect coronary classification and a high negative predictive value to rule out a significant stenosis. But it may miss atherosclerotic plaque, including unstable plaque. Recent studies have aimed at improving the characterization of individual plaques by EBCT. Despite validation against autopsy and angiography, the clinical utility of EBCT still is not well defined. Additional data on reproducibility and better consensus on criteria for abnormality for coronary calcification are advised.

Angiography↗
PubMed1993

Effect of motion on thallium-201 SPECT studies: a simulation and clinical study.

Although patient motion on 201Tl SPECT studies has been reported as a source of artifacts, systematic studies on motion patterns and resultant artifacts are lacking. Accordingly, we simulated 74 motion patterns upon a normal study. The tomograms were assessed for presence of defects: The "motion pixel area index" ranged from 1 to 83; 26 of 30 (87%) simulations with an index > or = 21 had defects, whereas 38 of 44 (86%) simulations with an index < 21 were normal. Defect location was dependent on motion direction; defect intensity was dependent on its magnitude and timing. Review of data acquisition in 164 recent normal patient studies revealed motion in 42 (26%). Motion was generally minimal and caused defects in only seven (4%). Thus, mild motion is unlikely to produce defects. In our laboratory, motion is now an infrequent source of artifacts; severe motion produces recognizable patterns that depend on its direction, magnitude and timing.

Adult↗
PubMed1992

Reproducibility of stress redistribution thallium-201 SPECT quantitative indexes of hypoperfused myocardium secondary to coronary artery disease.

To determine the reproducibility of quantitative indexes of hypoperfused myocardium by exercise thallium-201 single-photon emission computed tomography, duplicate studies were performed in 16 stable patients within 1 month. Twenty-three other patients, with intervals up to 13 months between studies, were retrospectively identified from medical records. Symptoms, weight, heart rate achieved and peak systolic blood pressure during the 2 studies were similar. Maximal counts circumferential profiles' polar maps were generated and divided into 3 vascular territories. The hypoperfused myocardium was defined as the percent stress profile points below the normal level. The observed values were compared between the 2 studies for each patient. Defect size ranged from 0 to 73%. The concordance correlation coefficient (a measure of the closeness of the data points to the line of identity) and mean absolute deviation were 0.94 and 4.5%, respectively, when all patients were considered together, 0.93 and 3.2%, respectively in the reproducibility group, and 0.94 and 5.1%, respectively, in the retrospective group. Inter- and intraobserver reproducibility were also very high. For individual vessels, the concordance correlation coefficients were all > or = 0.89 and the mean absolute deviations between 3.7 and 9%. Thus, in stable patients with repeat thallium studies within a year, the percent hypoperfused myocardium is highly reproducible.

Adult↗
PubMed1991

Comparison of thallium-201 SPECT and planar imaging methods for quantification of experimental myocardial infarct size.

To compare single photon emission computed tomography (SPECT) and planar thallium-201 (TI-201) myocardial perfusion imaging methods for quantification of left ventricular infarct size, 12 dogs with 6 to 8 hours of closed-chest coronary occlusion and 5 normal dogs were studied. After intravenous administration of TI-201, SPECT and three-view planar images were obtained. After the animals were put to death, hearts were sliced and stained with triphenyltetrazolium chloride (TTC) for planimetric determination of left ventricular infarct size. Infarct size on each SPECT slice and planar image was defined as the percentage of circumferential count profiles falling below the limits derived from normal dogs. Infarct size as a percentage of left ventricular mass was determined from SPECT and planar images before and after correcting for differences in myocardial slice mass from apex to base. The correlation coefficients, the concordance correlation coefficients (reflecting closeness to the line of identity), and the mean absolute deviations of the four methods versus TTC staining were 0.83, 0.77, and 5.1% (SPECT, no correction); 0.85, 0.84, and 3.7% (SPECT with correction); 0.81, 0.42, and 12.9% (planar, no correction); and 0.75, 0.49, and 10.4% (planar with correction). The regression lines did not differ from the line of identity for SPECT, whereas they differed significantly for planar imaging. Thus both SPECT and planar imaging are well suited for quantification of left ventricular infarct size. SPECT, however, appears to be superior to planar imaging, since its regression line more closely approximates the line of identity.

Animals↗
PubMed1985

Thallium-201 stress-redistribution myocardial rotational tomography: development of criteria for visual interpretation.

Despite high sensitivity and specificity for overall detection of coronary artery disease (CAD), planar stress-redistribution thallium-201 (Tl-201) scintigraphy remains suboptimal in localizing disease, because of overlap of myocardial segments. Single photon emission computerized tomography (SPECT), by providing three-dimensional representation of myocardial Tl-201, offers promise for improved localization of CAD. In 50 consecutive patients (22 normal and 28 with CAD), who underwent SPECT stress-redistribution Tl-201 imaging, we systemically developed visual interpretive criteria for perfusion abnormality on SPECT. For overall detection of disease, the best criterion for abnormality was greater than or equal to 8 sectors of moderately decreased Tl-201 uptake. With this criterion, the true positive and true negative rates for overall detection of disease were 96% and 91%, respectively. The best criterion for significant defect in the anterior or posterior coronary circulation was greater than or equal to 3 sectors of moderately decreased Tl-201 uptake. With this criterion, the true positive and true negative rates for anterior circulation disease were 71% and 100%, respectively. With respect to posterior circulation disease, the true positive and true negative rates were 100% and 50%, respectively. Regarding identification of dual circulation disease, the true positive and true negative rates were 71% and 82%, respectively.

Adult↗