Search PubMed⌕ Search

Biomedical subjects

F C Visser

Publications and source records attributed to F C Visser.

At least 37 records · Page 2Linked to original sources
PubMed2000

Magnetic resonance imaging of regional myocardial perfusion in patients with single-vessel coronary artery disease: quantitative comparison with (201)Thallium-SPECT and coronary angiography.

The clinical value of magnetic resonance perfusion imaging (MRI) was investigated by quantitative comparison with (201)thallium-single-photon emission computed tomography ((201)TI-SPECT) and quantitative coronary angiography (QCA). Short-axis imaging was performed during dipyridamole administration in 13 patients with single-vessel coronary artery disease. Using inner and outer contours, the myocardium was divided into 30 contiguous, radial regions. Defining a perfusion defect as a region with less than 90% of maximum (201)TI intensity, nine patients had a matching perfusion defect, two had no defect on both (201)TI-SPECT or MRI, and one had a defect on (201)TI-SPECT but not on MRI. One patient had a defect on both modalities but with inaccurate localization. Three perfusion parameters were investigated: a) maximum contrast enhancement (MCE); b) slope of the signal intensity versus time curve; and c) inverse mean transit time (1/MTT). The sensitivity and specificity of MCE in the detection of perfusion abnormalities with TI-SPECT as the reference method were 71% and 71%, respectively (slope 77% and 61%, 1/MTT 44% and 70%). Furthermore, correlations were calculated per patient for the entire circumference of the short-axis myocardium. Median correlations were as follows: MCE 0.92, slope 0.91, and 1/MTT 0.40. Mismatches between (201)TI defects and defects on MRI resulted in low mean correlations (MCE 0.45, slope 0.46, and 1/MTT 0.26). There was a trend between severity of perfusion defects on MRI (using MCE) and QCA stenosis area (r = -0.56, P = 0.06). Thus, MRI and (201)TI-SPECT demonstrate fair agreement in the assessment of perfusion defects but show moderate correlation when the entire short-axis myocardium is correlated.

Aged↗
PubMed1999

Isometric tension development and its calcium sensitivity in skinned myocyte-sized preparations from different regions of the human heart.

OBJECTIVE: In this study we investigated whether differences exist or develop in patients with aortic or mitral valve disease in myofibrillar contractile function and contractile protein composition between subendo- and subepicardial human ventricular tissue. Isometric tension, its calcium sensitivity and contractile protein composition were studied in left ventricular subendo- and subepicardial and in atrial biopsies obtained during open heart surgery from 24 patients with mitral or aortic valve disease. METHODS: Isometric tension was measured in mechanically isolated skinned myocyte-sized preparations at different free calcium concentrations at 15 degrees C. Protein composition was analysed by one-dimensional gel electrophoresis. A comparison was made between the results of subendo- and subepicardial ventricular tissue within each New York Heart Association class and within the different hemodynamically overloaded groups. RESULTS: Maximal isometric tension was significantly lower in atrial than in ventricular preparations. The concentration of calcium required for half-maximal activation was significantly higher in atrial than in ventricular preparations. Within the ventricle no differences were found in contractile protein composition, isometric tension and its calcium sensitivity between subendo- and subepicardial tissue when all patients were treated as one group or when patients were subdivided according to severity of heart disease or hemodynamic overload. CONCLUSIONS: In this group of patients with ventricular volume or pressure overload no regional differences exist or develop during cardiac disease in left ventricular myofibrillar protein composition and force production. Maximal isometric tension and its calcium sensitivity are smaller in atrial than in ventricular preparations.

Analysis of Variance↗
PubMed1999

Metabolism of radioiodinated fatty acid analogs in ischemic and hypoxic canine myocardium.

UNLABELLED: Myocardial metabolism of 17-[123I]-iodoheptadecanoic acid (IHDA), 15-(p-[131I]-iodophenyl)pentadecanoic acid (pIPPA) and 15-(p-[125I]-iodophenyl)-3,3-dimethylpentadecanoic acid (DMIPP) was assessed during ischemia and hypoxia. The simultaneous investigation allowed us to evaluate differences in metabolic handling of these three fatty acids. METHODS: In 17 open-chest dogs, the left ascending coronary artery was cannulated and extracorporeal bypass (ECB) perfused. In 3 dogs, ECB flow was kept normal, and these control experiments showed that kinetics of the radioiodinated fatty acids were not affected by the ECB technique itself. In 9 dogs, ECB flow was reduced to one third (ischemia), and in 5 dogs, the ECB area was perfused with venous blood and was kept at control values (hypoxia). After simultaneous intravenous injection of IHDA, pIPPA and DMIPP, seven paired biopsy specimens from the native and ECB-perfused myocardium were taken over an assay period of 35 min. Total activity and the distribution in the aqueous phase and lipid fractions were determined, and time-activity curves were constructed. RESULTS: In ischemic (Is) but not in hypoxic (Hy) myocardium, peak total activity of IHDA, pIPPA and DMIPP decreased significantly versus normal (N) myocardium (IHDA: N = 700 +/- 267 versus Is = 335 +/- 158 dpm/mg/mCi; pIPPA: N = 988 +/- 318 versus Is = 438 +/- 180 dpm/mg/mCi; DMIPP: N = 352 +/- 146 versus Is = 179 +/- 82 dpm/mg/mCi; all P values < 0.001). The relative decrease was similar for IHDA, pIPPA or DMIPP. Half-time values of total activity were prolonged for IHDA and pIPPA but were shortened for DMIPP in ischemic and hypoxic myocardium (IHDA: N = 22, Is = 44 and Hy = 50 min; pIPPA: N = 24, Is = 95 and Hy = 169 min; DMIPP: N = 528, Is = 409 and Hy = 115 min). The aqueous phase activity for IHDA, pIPPA and DMIPP decreased significantly versus normal myocardium in both ischemic (IHDA: N = 71% +/- 9% versus Is = 36% +/- 9%, P < 0.001; pIPPA: N = 62% +/- 10% versus Is = 25% +/- 8%, P < 0.001; DMIPP: N = 26% +/- 11% versus Is = 18% +/- 3%, P < 0.05) and hypoxic (IHDA: N = 76% +/- 8% versus Hy = 62% +/- 8%, P < 0.05; pIPPA: N = 66% +/- 8% versus Hy = 46% +/- 10%, P < 0.05; DMIPP: N = 32% +/- 6% versus Hy = 24% +/- 4%, P < 0.05) myocardium. The relative decrease was significantly highest for pIPPA and lowest for DMIPP. Incorporation into triacylglycerols increased significantly for IHDA, pIPPA and DMIPP in both ischemic and hypoxic myocardium. In normal myocardium, DMIPP was already mainly incorporated into triacylglycerols. Activity of IHDA and pIPPA in acylcarnitine increased significantly in ischemic and hypoxic myocardium. CONCLUSION: Kinetics of the radioiodinated fatty acid analogs in myocardium are altered during oxygen deprivation in a similar fashion as documented in literature for natural fatty acids. However, the changes were different between IHDA, pIPPA and DMIPP, suggesting different metabolic handling and thus reflecting different aspects of myocardial fatty acid metabolism.

Animals↗
PubMed1999

Prediction of improvement of regional left ventricular function after revascularization using different perfusion-metabolism criteria.

UNLABELLED: Increased myocardial uptake of 18F-fluorodeoxyglucose (FDG) in regions with perfusion defects (perfusion-FDG mismatch) has been shown to predict functional recovery after revascularization; conversely, a concordant decrease in perfusion and FDG uptake (perfusion-FDG match) represents scar tissue (varying from subendocardial to transmural scar) that will not improve in contractile function after revascularization. Several recent studies have used a mild reduction in perfusion or FDG uptake (or both) as an indicator of viable tissue. To our knowledge, this criterion has not been validated against functional outcome after revascularization. This study aimed to compare the predictive value for functional recovery of these different perfusion-metabolism criteria. METHODS: Forty-two patients referred for revascularization were studied with early resting 201Tl SPECT (to evaluate perfusion) and FDG SPECT. Contractile function was evaluated before and 3-4 mo after revascularization using two-dimensional echocardiography. Angiography was not repeated. RESULTS: Two hundred six dysfunctional segments were identified; functional recovery occurred in 71 segments. The 206 dysfunctional segments were divided into five groups: group I, segments (n = 37) with normal perfusion; group II, segments (n = 69) with a mild reduction in perfusion (> or =60% of normal 201Tl uptake) without increased FDG uptake (mild match); group III, segments (n = 29) with a mild reduction in perfusion and increased FDG uptake (mild mismatch); group IV, segments (n = 46) with a more severe reduction in perfusion (<60% of normal 201Tl uptake) without increased FDG uptake (severe match); and group V, segments (n = 25) with a 201Tl activity < 60% and increased FDG uptake (severe mismatch). The mean wall motion score improved significantly in groups I, III and V but not in groups II and IV. Improvement of function was observed in 76% of group I segments, in 69% of group III segments and in 68% of group V segments. In contrast, only 13% of group II segments and 7% of group IV segments improved after revascularization. CONCLUSION: The results indicate that normal perfusion and mismatch patterns (either mild or severe) are predictive of functional recovery, whereas match patterns (either mild or severe) are predictive of absence of recovery. Match patterns are likely to represent different degrees of scar tissue, ranging from subendocardial to transmural scars. To identify segments with a high likelihood of improvement of function after revascularization, integration of information on perfusion and FDG uptake appears mandatory.

Angioplasty, Balloon, Coronary↗
PubMed1998

Predictive value of planar 18F-fluorodeoxyglucose imaging for cardiac events in patients after acute myocardial infarction.

This long-term study examines the predictive value of planar myocardial 18F-fluorodeoxyglucose (FDG) imaging for cardiac events after acute myocardial infarction (AMI). From December 1989 to April 1991, 59 consecutive patients with AMI had undergone planar rest thallium-201 (Tl-201)/FDG imaging for viability assessment; 53 (42 men) were included in this study. Mean follow-up was 47 +/- 15 months. Cardiac events were defined as cardiac-related death, reinfarction, late revascularization, and unstable angina pectoris. A mismatch pattern was defined as a FDG uptake exceeding Tl-201 uptake by > or = 20%. A concordant reduction in flow and metabolism was defined as a match. In the mismatch group (n = 39) were 19 events versus 1 event in the match group (n = 14) (p <0.009). In the mismatch group were 5 cardiac deaths, 3 reinfarctions, 7 late revascularizations, and 4 patients had unstable angina pectoris. There was 1 cardiac death in the match group. The event-free rate estimated using Kaplan Meier curves for patients with and without a mismatch was significantly different (p = 0.018). The relative risk for patients with a mismatch for developing a future cardiac event was estimated at 7.8 versus patients with a match. Thus, planar myocardial FDG imaging shortly after AMI has important prognostic significance for prediction of future cardiac events. Patients with a mismatch shortly after AMI have a high risk for future cardiac events on medical therapy.

Aged↗
PubMed1998

Force production in mechanically isolated cardiac myocytes from human ventricular muscle tissue.

OBJECTIVE: The expression of contractile isoforms changes during various pathological conditions but little is known about the consequences of these changes for the mechanical properties in human ventricular muscle. We investigated the feasibility of simultaneous determination of protein composition and isometric force development in single cardiac myocytes from human ventricular muscle tissue obtained from small biopsies taken during open heart surgery. METHODS: Small biopsies of about 3 mg wet weight were taken during open heart surgery from patients with aortic valve stenosis. These biopsies were divided in two parts. One part (approximately 2 mg) was used for mechanical isolation of single myocytes and subsequent force measurement while the remaining part was used, in aliquots of 1 microgram dry weight, for protein analysis by polyacrylamide gel electrophoresis. The myocytes were attached with silicon glue to a sensitive force transducer and a piezoelectric motor, mounted on an inverted microscope and permeabilized by means of Triton X-100. Force development was studied at various free calcium concentrations. RESULTS: From all biopsies, myocytes could be obtained and the composition of contractile proteins could be determined. The average isometric force (+/- s.e.m.) at saturating calcium concentration obtained on 20 myocytes from 5 patients amounted to 51 +/- 8 kN/m2. Force was half maximal at a calcium concentration of 2.47 +/- 0.10 microM. CONCLUSION: These measurements indicate that it is possible to study the correlation between mechanical properties and protein composition in small biopsies from human ventricular muscle.

Adult↗
PubMed1998

Ejection fraction improvement by beta-blocker treatment in patients with heart failure: an analysis of studies published in the literature.

Because ejection fraction (EF) is one of the most important predictors of survival in patients with left ventricular (LV) dysfunction and because Packer showed a large reduction in mortality figures with carvedilol, in contrast to former studies with bisoprolol and metoprolol, we investigated if this difference in survival may be related to a difference in improvement of LV function by different beta-blockers. We searched the MEDLINE database and all reference lists of articles obtained through the search for the relation between beta-blocker treatment and improvement in EF. Forty-one studies met the criteria and we added two of our own studies. Four hundred and fifty-eight patients were treated with metoprolol with a mean follow-up of 9.5 months and a mean increase in EF of 7.4 EF units. One thousand thirty patients were treated with carvedilol with a mean follow up of 7 months and a mean increase in EF of 5.7 EF units. One hundred ninety-nine patients were treated with bucindolol with a mean follow-up of 4 months and a mean increase in EF of 4.6 EF units. Several small studies with nebivolol, atenolol, and propranolol were also studied and, when combined, the mean increase in EF was 8.6 EF units. When patients with idiopathic and ischemic cardiomyopathies were compared, the average increase in EF units was 8.5 vs. 6.0, respectively. The use of beta-blocker treatment in heart failure patients, irrespective of the etiology, improved LV function in almost all studies and it appears that the differences among beta-blockers and among etiologies is small and probably insignificant. However, there is a difference in survival rate when the various beta-blockers are compared, suggesting that mechanisms other than improvement of LV function by beta-blockers are responsible for the difference in survival.

Adrenergic beta-Antagonists↗
PubMed1998

Increased uptake of iodine-123-BMIPP in chronic ischemic heart disease: comparison with fluorine-18-FDG SPECT.

UNLABELLED: To evaluate the potential role of 15-p-[123I]iodophenyl-3-(R,S)-methylpentadecanoic acid (BMIPP) for the assessment of myocardial viability, the patterns of BMIPP versus 18F-fluorodeoxyglucose (FDG) uptake were evaluated in patients with chronic ischemic heart disease. METHODS: Twenty-one patients with stable chronic coronary artery disease underwent resting TI SPECT to delineate myocardial perfusion followed by FDG SPECT to detect residual viability in regions showing perfusion defects. Resting BMIPP SPECT was obtained on a separate day. SPECT images were displayed as polar maps (13 segments) and analyzed semiquantitatively. A total of 273 segments were analyzed. RESULTS: In 87 (32%) of the segments, a perfusion defect was observed. In perfusion defects, the distributions of BMIPP/TI (mis)matches were significantly different (p < 0.0001) between the FDG viable (n = 42) and nonviable (n = 45) segments. A BMIPP/TI mismatch (BMIPP uptake higher than perfusion) was found in 74% of FDG viable segments, whereas a BMIPP/TI match (BMIPP uptake equal or lower than perfusion) was found in 69% of FDG nonviable segments. Agreement between matching or mismatching of segments was assessed to be 71%. Agreement was 81% when the data were analyzed on a patient basis. The observed frequency of BMIPP/TI mismatches was significantly higher (p < 0.05) in segments with an old myocardial infarction (20 of 36; 55%) than it was in subacute infarcted myocardium (5 of 21; 24%). CONCLUSION: In chronically hypoperfused myocardium, an increased BMIPP uptake relative to perfusion was detected, which is different from the decreased BMIPP uptake often reported in (sub)acute myocardial ischemia. Therefore, the interval from infarction may be an important factor in the interpretation of BMIPP scintigraphic data. Increased BMIPP uptake was associated with FDG/TI mismatches and may, therefore, confirm myocardial viability. Some segments with a FDG/TI mismatch, however, revealed a BMIPP/TI match. These segments may contain viable but more severely damaged tissue. Further studies on functional recovery are warranted to assess the significance of a BMIPP/perfusion (mis)match for tissue viability.

Aged↗
PubMed1998

Fluorine-18-fluorodeoxyglucose cardiac imaging using a modified scintillation camera.

Conventional 201TI and hexakis 2-methoxy-2-isobutyl isonitrile studies are less accurate as compared to FDG PET in the prediction of functional recovery after revascularization in patients with injured but viable myocardium. The introduction of a dual-head variable-angle-geometry scintillation camera equipped with thicker crystals (5/8 in.) and high-resolution, ultrahigh-energy collimators capable of 511 keV imaging has permitted FDG SPECT to provide information equivalent to that of PET for the detection of injured but viable myocardium in patients with chronic ischemic heart disease. The development of standardized glucose-loading protocols, including glucose-insulin-potassium infusion and the potential use of nicotinic acid derivatives, has simplified the method of obtaining consistently good-to-excellent quality FDG SPECT cardiac studies. FDG SPECT may become the modality of choice for evaluating injured but viable myocardium because of enhanced availability of FDG, logistics, patient convenience, accuracy and cost-effectiveness compared to PET.

Equipment Design↗
PubMed1997

Accuracy of currently available techniques for prediction of functional recovery after revascularization in patients with left ventricular dysfunction due to chronic coronary artery disease: comparison of pooled data.

OBJECTIVES: This study evaluated the relative merits of the most frequently used techniques for predicting improvement in regional contractile function after coronary revascularization in patients with left ventricular dysfunction due to chronic coronary artery disease. BACKGROUND: Several techniques have been proposed for predicting improvement in regional contractile function after revascularization, including thallium-201 (Tl-201) stress-redistribution-reinjection, Tl-201 rest-redistribution, fluorine-18 fluorodeoxyglucose with positron emission tomography, technetium-99m sestamibi imaging and low dose dobutamine echocardiography (LDDE). METHODS: A systematic review of all reports on prediction of functional recovery after revascularization in patients with chronic coronary artery disease (published between 1980 and March 1997) revealed 37 with sufficient details for calculating the sensitivity and specificity of each imaging modality. From the pooled data, 95% and 99% confidence intervals were also calculated. RESULTS: Sensitivity for predicting regional functional recovery after revascularization was high for all techniques. The specificity of both Tl-201 protocols was significantly lower (p < 0.05) and LDDE significantly higher (p < 0.01) than that of the other techniques. CONCLUSIONS: Pooled analysis of 37 studies showed that although all techniques accurately identify segments with improved contractile function after revascularization, the Tl-201 protocols may overestimate functional recovery. The evidence available thus far indicates that LDDE appears to have the highest predictive accuracy.

Chronic Disease↗
PubMed1997

[Angiotensin-converting enzyme inhibitors following a myocardial infarct: clinical abd echographic indications].

-Angiotensin converting enzyme (ACE) inhibitors can limit mortality and the occurrence of cardiac failure after myocardial infarction because they interfere with the ventricular remodelling process. ACE inhibitors also have anti-arrhythmic and possibly anti-ischaemic potency and therefore a primary cardioprotective effect. It is not advised to treat all patients with a myocardial infarction with an ACE inhibitor, but patients with a large anterior wall infarct, with heart failure or who had a previous infarct should be treated. After three months, the remodelling process can be reevaluated. The ACE inhibitor can be discontinued if the left ventricular function has strongly improved. There is no preference for a particular ACE inhibitor.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

Comparison between 360 degrees and 180 degrees data sampling in thallium-201 rest-redistribution single-photon emission tomography to predict functional recovery after revascularization.

Whether 360 degrees or 180 degrees imaging should be used in cardiac thallium-201 single-photon emission tomography (SPET) studies to detect coronary artery disease remains controversial. Moreover, the relative diagnostic accuracy of 360 degrees and 180 degrees 201Tl SPET for the assessment of myocardial viability has never previously been studied. The aim of this study was to perform a direct comparison between 180 degrees and 360 degrees data sampling to detect viable myocardium in patients undergoing revascularization; in order to allow optimal detection of viability a rest-redistribution protocol was used. The 201Tl results were compared with improvement of regional wall motion abnormalities after the revascularization, which was considered as the "gold standard" for myocardial viability. Thirty-two patients, scheduled for revascularization, underwent rest-redistribution 201Tl SPET, using a 360 degrees arc. Raw data along a 180 degrees arc (45 degrees RAO to LPO) were selected from the original 360 degrees data sets (both early an late 201Tl images). All SPET data were analysed semiquantitatively using circumferential profiles of the short-axis images; the data were displayed in polar maps. Criteria for viability included percentage 201Tl redistribution and percentage 201Tl activity on the late image. Regional wall motion was assessed with two-dimensional echocardiography before and 3 months after revascularization. The sensitivities of 360 degrees and 180 degrees imaging for the prediction of functional recovery were 82% and 89%, respectively, whereas the specificities were 51% and 55%, respectively. The diagnostic accuracy of 360 degrees imaging was 62% and that of 180 degrees imaging 67%. This study shows that 360 degrees and 180 degrees imaging have comparable diagnostic accuracy in the prediction of functional recovery after revascularization. With the newer dual-head gamma camera systems with each detector opposing each other, 360 degrees imaging may be preferred.

Angioplasty, Balloon, Coronary↗
PubMed1997

Optimal metabolic conditions during fluorine-18 fluorodeoxyglucose imaging; a comparative study using different protocols.

Positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (FDG) can identify viable myocardium in patients with coronary artery disease. Recently, FDG imaging with single-photon emission tomography (SPET) and 511-keV collimators has been described. To obtain optimal image quality in all patients, cardiac FDG studies should be performed during hyperinsulinaemic glucose clamping. It has been suggested that FDG imaging after the administration of a nicotinic acid derivative may yield comparable image quality to clamping. We studied eight patients and compared the image quality of cardiac FDG SPET studies after oral glucose loading, after administration of a nicotinic acid derivative (acipimox, 250 mg orally) and during hyperinsulinaemic glucose clamping. The image quality was expressed as the myocardial to blood pool (M/B) activity ratio, which is used as a measure of the target-to-background ratio The M/B ratios were comparable after clamping and acipimox (2.8+/-0.8 vs 2.9+/-0.7), whereas the M/B ratio was lower after oral glucose loading (2.2+/-0.3, P<0.05 vs clamp and acipimox). To determine the clearance of FDG from the plasma, blood samples were drawn at fixed time intervals and the FDG activity was measured in a gamma well counter. The FDG clearance was significantly lower after oral glucose loading (T(1/2) oral load=16. 2+/-5.7 min) as compared with clamping (T(1/2) clamp=8.1+/-3.1 min) and acipimox (T(1/2) acipimox=10.7+/-4.0 min, NS vs clamp, P<0.05 vs oral load). It may be concluded that FDG SPET imaging after acipimox administration yields image quality and clearance rates comparable to those obtained during clamping. FDG SPET in combination with acipimox may useful in clinical routine for the assessment of myocardial viability.

Aged↗
PubMed1997

Prediction of improvement of contractile function in patients with ischemic ventricular dysfunction after revascularization by fluorine-18 fluorodeoxyglucose single-photon emission computed tomography.

OBJECTIVES: We evaluated the use of fluorine-18 fluorodeoxyglucose (FDG) and single-photon emission computed tomography (SPECT) to predict improvement of left ventricular ejection fraction (LVEF) after revascularization. BACKGROUND: FDG SPECT has recently been proposed for assessment of myocardial viability. However, FDG SPECT still awaits validation in terms of predicting improvement of contractile function after revascularization in patients with poor left ventricular (LV) function. METHODS: Fifty-five patients with contractile dysfunction (including 22 with LVEF < 30%) underwent FDG SPECT during hyperinsulinemic glucose clamping and early thallium-201 SPECT (to assess perfusion). Improvement of LV function was evaluated 3 months after revascularization with echocardiography and radionuclide ventriculography. RESULTS: The 55 patients were arbitrarily classified into two groups: 19 with three or more viable, dysfunctional segments on FDG SPECT and 36 with less than three viable, dysfunctional segments. LVEF increased significantly in the first group, from 28 +/- 8% (mean +/- SD) before to 35 +/- 9% (p < 0.01) after revascularization. In the second group, LVEF remained unchanged after revascularization (45 +/- 14% vs. 44 +/- 14%, p = NS). The 22 patients with severely depressed LV function were similarly classified into two groups: 14 with three or more viable segments on FDG SPECT in whom LVEF improved significantly (25 +/- 6% vs. 32 +/- 6%) and 8 with less than three viable segments in whom LVEF remained unchanged (24 +/- 6% vs. 25 +/- 6%). CONCLUSIONS: This study shows that FDG SPECT can identify patients in whom LV function improves after revascularization. Because SPECT is widely available, this technique may contribute to more routine use of FDG for determination of viability.

Echocardiography↗
PubMed1997

Myocardial perfusion imaging: clinical experience and recent progress in radionuclide scintigraphy and magnetic resonance imaging.

In the past 20 years, radionuclide scintigraphy has proven to be a sensitive clinical tool in the assessment of myocardial perfusion abnormalities. Magnetic resonance imaging may also be used to study myocardial perfusion, but its potential value still has to emerge in the clinical setting. This review addresses the potential and achievements of both methods in clinical cardiology.

Animals↗
PubMed1997

Metabolic imaging using F18-fluorodeoxyglucose to assess myocardial viability.

Over the past 10 years, F18-fluorodeoxyglucose (FDG) imaging with positron emission tomography (PET) has emerged as an important technique in the delineation of myocardial viability. Using this technique it has become possible to predict recovery of ventricular function after revascularization in patients with chronic coronary artery disease. Data from long-term (although retrospective) follow-up studies have demonstrated that patients with viable myocardium on FDG PET who do not undergo revascularization are prone to cardiac events, including cardiac death and non-fatal infarction. The same studies have pointed out that patients with viable tissue on FDG PET, who do undergo revascularization, improve substantially in symptoms related to congestive heart failure. To allow FDG imaging in centers without PET equipment, recent studies have evaluated the use of FDG imaging with single photon emission computed tomography (SPECT) and 511 keV collimators. Preliminary data using this alternative approach are promising, but need further confirmation. In this review the experience with FDG imaging (using either PET or SPECT) in the assessment of tissue viability in patients with coronary artery disease will be discussed.

Coronary Disease↗
PubMed1997

FDG SPECT in the assessment of myocardial viability. Comparison with dobutamine echo.

The use of 18F-fluorodeoxyglucose (FDG) imaging with single photon emission computed tomography (SPECT) has been introduced recently to assess myocardial viability. Several centres have now gained experience with cardiac FDG SPECT imaging, and this report is a summary of the currently available FDG SPECT data. Three studies have compared FDG SPECT with FDG positron emission tomography and demonstrated good agreement between them. Initial results in patients undergoing revascularization suggest that FDG SPECT can predict improvement in contractile function after revascularization. Although the initial results are promising, larger studies are needed to determine the precise role of FDG SPECT in the assessment of myocardial viability.

Cardiotonic Agents↗