Brain perfusion patterns in familial frontotemporal lobar degeneration.

OBJECTIVE: Frontotemporal lobar degeneration (FTLD) is a clinically, genetically, and pathologically heterogeneous disorder. The aim of this study was to compare clinical features and perfusion patterns on SPECT of patients with familial FTLD-TAR DNA binding protein 43 kDa (TDP) and MAPT mutations. METHODS: Patients were included if they had MAPT or GRN mutations, positive family history with pathologically proven FTLD in the patient or first-degree relative, or were part of FTD-MND families. All patients and 10 age- and gender-matched controls underwent measurement of brain perfusion using (99m)Tc-HMPAO SPECT. We used SPM8 to perform image processing and voxel-based group analyses (p < 0.001). Gender and age were included as nuisance variables in the design matrices. RESULTS: Of the 29 patients with familial FTLD, 19 had familial FTLD-TDP (GRN mutations in 6), and 10 had MAPT mutations. At clinical presentation, familial FTLD-TDP patients were older at onset (p = 0.030) and had more memory deficits (p = 0.011), whereas patients with MAPT had more naming deficits (p < 0.001) and obsessive-compulsive behavior (p = 0.001). The between-groups SPECT analyses revealed significantly less perfusion in the right frontal lobe, precuneus, cuneus, and inferior parietal lobule in familial FTLD-TDP, whereas significantly less perfusion was found in the left temporal and inferior frontal gyri in MAPT. Post hoc analysis of familial FTLD-TDP with unknown genetic defect vs MAPT revealed less perfusion in the right frontal and parietal lobe. CONCLUSION: Familial FTLD-TDP shows relatively more posterior hypoperfusion, including the precuneus and inferior parietal lobule, possibly related to significant memory impairment. Patients with MAPT were characterized by impaired perfusion of the temporal regions and naming deficits.

Somatostatin receptor scintigraphy in the follow-up of patients with differentiated thyroid cancer.

UNLABELLED: The aim of this study was to compare the results of somatostatin receptor scintigraphy (SRS) and of radioiodine scintigraphy in patients with metastatic differentiated thyroid carcinoma during L-thyroxine suppression therapy and after withdrawal. Twenty-five patients were studied: 16 patients had papillary cancer and 12 of them had metastatic disease; 9 patients had follicular cancer and 7 of these had known metastases. In 7 patients SRS was performed during thyroxine withdrawal, in 12 during thyroxine therapy within 9 months from radioiodine scintigraphy, in 6 others both during suppression therapy and after withdrawal. SRS was positive in 18 of 25 (72%) patients. It demonstrated lesions in 11 of 13 (85%) patients after thyroxine withdrawal and in 12 of 18 (67%) patients during thyroxine suppression. In 6 patients in whom a direct comparison was made before and after withdrawal, essentially the same information was obtained. Six of 8 (75%) patients with lesions that did not concentrate radioiodine showed uptake of labeled octreotide in these lesions. In 5 of 17 (29%) patients whose tumors concentrated radioiodine, no uptake was found during SRS. CONCLUSIONS: 1) in patients with metastatic differentiated thyroid carcinoma, tumor sites can be visualized using SRS; 2) there is no need to withdraw patients from suppression therapy in order to perform SRS; 3) in some patients whose lesions do concentrate labeled octreotide but not radioiodine, the use of somatostatin analogues labeled with (111)In or [90Y] can provide new therapeutic options.

Safety, hemodynamic profile, and feasibility of dobutamine stress technetium myocardial perfusion single-photon emission CT imaging for evaluation of coronary artery disease in the elderly.

OBJECTIVES: Cardiovascular disease is the leading cause of morbidity and mortality in the elderly. The evaluation of coronary artery disease by exercise stress testing is frequently limited by the patient's inability to exercise. Although pharmacologic stress testing with dobutamine is an alternative, the safety of dobutamine myocardial perfusion scintigraphy in the elderly has not been previously studied. PATIENTS AND METHODS: We studied the safety and feasibility of dobutamine (up to 40 microg/kg/min)-atropine (up to 1 mg) stress myocardial perfusion scintigraphy using technetium single-photon emission CT imaging in 227 patients > or = 70 years old (mean +/- SD age, 75 +/- 4 years). A control group of 227 patients < 70 years old (mean age, 55 +/- 11 years; matched for gender, prevalence of previous infarction, beta-blocker therapy, and severity of resting perfusion abnormalities) was studied to assess age-related differences in the safety and the hemodynamic response. A feasible test was defined as the achievement of the target heart rate and/or an ischemic end point (angina, ST-segment depression, or reversible perfusion abnormalities). RESULTS: No myocardial infarction or death occurred during the test. The target heart rate was achieved more frequently in the elderly patients (87% vs 79%; p < 0.05). The elderly patients had a higher prevalence of supraventricular tachycardia (7% vs 1%; p < 0.005) and premature ventricular contraction (74% vs 32%; p < 0.005) during the test, as compared to the younger patients. There was a trend to a higher prevalence of ventricular tachycardia (5% vs 2%) and atrial fibrillation (3% vs 0.4%) in the elderly patients. Arrhythmias were terminated spontaneously by termination of dobutamine infusion or by administration of metoprolol. Independent predictors of supraventricular tachyarrhythmias and ventricular tachycardia were older age (p < 0.001; chi(2), 9.8) and myocardial perfusion defect score at rest (p < 0.01; chi(2), 6.8) respectively, by using a multivariate analysis of clinical and stress test variables. Elderly patients had a higher prevalence of systolic BP drop > 20 mm Hg during the test (37% vs 12%; p < 0.05). The test was terminated due to hypotension in 2% of the elderly patients and in 1% of the control group. Age was the most powerful predictor of hypotension (p < 0.005; chi(2), 10.3). The test was considered feasible in 216 elderly patients (95%) and in 209 patients of the control group (92%). CONCLUSION: Dobutamine-atropine stress myocardial perfusion scintigraphy is a highly feasible method for the evaluation of coronary artery disease in the elderly. Elderly patients have a higher risk for developing hypotension and supraventricular tachyarrhythmias during a dobutamine stress test. However, dobutamine-induced hypotension is often asymptomatic and rarely necessitates the termination of the test.

Dobutamine stress thallium-201 single-photon emission tomography versus echocardiography for evaluation of the extent and location of coronary artery disease late after myocardial infarction.

Dobutamine stress echocardiography and thallium-201 myocardial perfusion scintigraphy are clinically useful methods for the evaluation of coronary artery disease (CAD). However, the relative merits of these imaging modalities in the evaluation of the extent of CAD after myocardial infarction have not been well studied. The aim of this study was to compare the accuracy of dobutamine stress echocardiography and simultaneous 201Tl single-photon emission tomography (SPET) imaging for the diagnosis and localization of CAD late after acute myocardial infarction. Dobutamine (up to 40 micrograms kg-1 min-1)-atropine (up to 1 mg) stress echocardiography in conjunction with stress-reinjection 201Tl SPET was performed for the evaluation of myocardial ischaemia in 90 patients with previous myocardial infarction who underwent coronary angiography. Significant CAD was predicted on bases of myocardial ischemia (new or worsening wall motion abnormalities on echocardiography and reversible perfusion defects on 201Tl SPET). Significant CAD (> or = 50% luminal diameter stenosis) was detected in 73 (81%) patients. The sensitivity, specificity and accuracy of echocardiography in detecting remote ischaemia for the diagnosis of remote CAD (present in 53 patients) were, respectively, 79% (CI 70%-88%), 85% (CI 77%-93%) and 81% (CI 73%-90%), while the corresponding figures for 201Tl SPET were 75% (CI 66%-85%), 78% (CI 69%-87%) and 76% (CI 67%-86%) respectively (P = NS vs echocardiography). The sensitivity, specificity and accuracy of echocardiography in detecting peri-infarction ischaemia for the diagnosis of infarct-related artery stenosis (present in 70 patients) were, respectively, 77% (CI 68%-86%), 85% (CI 78%-92%) and 79% (CI 70%-87%) while the corresponding figures for 201Tl SPET were 73% (CI 64%-82%), 85% (CI 78%-92%) and 76% (CI 67%-84%) respectively (P = NS vs echocardiography). The agreement between the two methods for the diagnosis of peri-infarction and remote ischaemia was 70% (kappa = 0.37) and 80% (kappa = 0.59) respectively. It is concluded that dobutamine stress echocardiography and 201Tl SPET have comparable accuracy for the diagnosis of infarct related and remote CAD in patients with previous myocardial infarction. The agreement between the methods is higher for the diagnosis of remote CAD than for that of peri-infarction ischaemia.

Comparison of iodine-123 epidepride and iodine-123 IBZM for dopamine D2 receptor imaging in clinically non-functioning pituitary macroadenomas and macroprolactinomas.

UNLABELLED: We compared pituitary iodine-123 epide- pride single-photon emission tomography (SPET) and 123I-IBZM SPET for the in vivo imaging of dopamine D2 receptors in 15 patients with clinically non-functioning pituitary adenomas. Four patients with dopamine agonist-sensitive macroprolactinomas were studied as positive controls. The uptake of radioactivity in the pituitary was established using a visual scoring system and an uptake index calculated by dividing the average count rates in the pituitary area by the average count rates in the cerebellum. All four macroprolactinomas showed specific binding of 123I-epidepride, but only one showed specific binding of 123I-IBZM. Specific binding of 123I-epidepride was demonstrated in 9 of the 15 clinically non-functioning pituitary adenomas (60%), but specific binding of 123I-IBZM was shown in only 6 of these 15 cases (40%). The uptake of 123I-epidepride in the pituitary region was consistently higher than that of 123I-IBZM. None of the patients who showed absence of uptake of 123I-epidepride in the pituitary area showed uptake of 123I-IBZM in this area. IN CONCLUSION: 123I-epidepride SPET is superior to 123I-IBZM SPET for the visualization of dopamine receptor-positive pituitary adenomas. Therefore, 123I-epidepride should replace 123I-IBZM for future D2 receptor SPET studies of pituitary adenomas. 123I-epidepride SPET potentially might serve to predict the response of clinically non-functioning pituitary adenomas to dopamine agonist therapy.

Safety of dobutamine-atropine stress myocardial perfusion scintigraphy.

UNLABELLED: Dobutamine stress testing is increasingly used for the diagnosis and functional evaluation of coronary artery disease. However, the relationship between myocardial perfusion abnormalities and complications of the test has not been studied. METHODS: We studied the hemodynamic profile, safety and feasibility of dobutamine (up to 40 microg/kg/min)-atropine (up to 1 mg) stress myocardial perfusion SPECT imaging (with 201TI, 99mTc-MIBI or tetrofosmin) in a consecutive series of 1076 patients (age = 59 +/- 11 yr, 50% with previous myocardial infarction) referred for evaluation of myocardial ischemia. RESULTS: No infarction or death occurred during the test. The test was considered feasible (achievement of 85% of the target heart rate or an ischemic endpoint) in 1005 patients (94%). Hypotension (systolic blood pressure drop > or = 40 mm Hg) occurred in 37 patients (3.4%). Independent predictors were higher baseline systolic blood pressure (p < 0.0001), number of ischemic segments (p < 0.05) and age (p < 0.05). Supraventricular tachyarrhythmias occurred in 48 patients (4.4%). Independent predictors were fixed perfusion defect (infarction) score (p < 0.005) and age (p < 0.05). Ventricular tachycardia occurred in 41 patients (3.8%). Independent predictors were infarction score (p < 0.01) and male gender (p < 0.05). All arrhythmias terminated spontaneously or after metoprolol administration. CONCLUSION: Dobutamine-atropine myocardial perfusion scintigraphy is a feasible method for the evaluation of coronary artery disease with a safety profile and feasibility comparable to those reported for dobutamine stress echocardiography. Patients with more severe fixed perfusion abnormalities are at a higher risk of developing tachyarrhythmias during the test.

Cardiac imaging for risk stratification with dobutamine-atropine stress testing in patients with chest pain. Echocardiography, perfusion scintigraphy, or both?

BACKGROUND: Pharmacological stress echocardiography and myocardial perfusion scintigraphy are used frequently for risk stratification in patients with suspected myocardial ischemia. However, their relative prognostic strength has never been explored. METHODS AND RESULTS: Two hundred twenty consecutive patients with chest pain (mean age, 60 +/- 12 years; 124 men, 115 with previous myocardial infarction) were studied with dobutamine-atropine stress echocardiography (ECHO) and simultaneous 99mTc sestamibi single photon emission computed tomography imaging (MIBI). Ischemia was defined as deterioration in left ventricular wall motion and reversible perfusion defects, respectively. ECHO was positive for ischemia in 76 and MIBI in 91 patients (agreement, 77%; kappa = .51). During follow-up of 31 +/- 15 months, 24 patients had hard cardiac events (nonfatal myocardial infarction or cardiac death). By univariate analysis, age, history of congestive heart failure, and any abnormality or ischemia on ECHO or MIBI were associated with cardiac events. Multivariate analysis revealed that age, abnormal ECHO (odds ratio [OR], 18.9; 95% CI, 2.5 to 146.0) or MIBI (OR, 12.8; 95% CI, 1.7 to 98.3), and ischemia on ECHO (OR, 4.0; 95% CI, 1.6 to 9.9) or MIBI (OR, 3.0; 95% CI, 1.2 to 7.4) had independent predictive values. When ECHO was used as a first option, the addition of MIBI to all nonischemic ECHO studies decreased the OR from 4.0 (95% CI, 1.6 to 9.9) to 3.8 (95% CI, 1.4 to 10.2). Addition of MIBI confined to nonischemic ECHO studies in which target heart rate was not attained (nondiagnostic studies) increased the OR to a maximal 5.7 (95% CI, 2.2 to 15.0). In contrast, the addition of ECHO to nondiagnostic MIBI studies was not useful. CONCLUSIONS: Dobutamine-atropine ECHO and MIBI provide comparable prognostic information. The addition of MIBI to ECHO may be useful in patients with nondiagnostic ECHO studies.

Prognostic significance of systolic blood pressure changes during dobutamine-atropine stress technetium-99m sestamibi perfusion scintigraphy in patients with chest pain and known or suspected coronary artery disease.

To investigate the prognostic value of dobutamine stress-induced changes in systolic blood pressure (BP) 418 patients (mean age 60 years, 238 men) with chest pain and known or suspected coronary artery disease, who underwent a dobutamine-atropine stress technetium-99m sestamibi myocardial perfusion scintigraphic study, were followed up for 25 +/- 15 months. Blood pressure was measured by automatic sphygmomanometry every 3 minutes. A marked decrease and increase in systolic BP from rest to peak were defined as changes of > or = 20 mm Hg, and > or = 30 mm Hg, respectively. Worst outcome events were cardiac death (n = 30), nonfatal myocardial infarction (n = 17), and hospitalization for congestive heart failure (n = 8). A decrease in systolic BP (prevalence 16%) was associated with older age and higher baseline systolic BP. Fixed and reversible sestamibi perfusion defects and follow-up results were similar to patients without a systolic BP decrease. In contrast, an increase in systolic BP (prevalence 24%) was associated with younger age, lower baseline systolic BP, and with absence of a history of prior congestive heart failure or treatment with angiotensin-converting enzyme inhibitors. Furthermore, these patients had fewer fixed perfusion defects and tended to have fewer annual event rates (3.5% vs 7.5%, p < 0.10). In a multivariate model, an increase in systolic BP was not an independent predictor for subsequent events. In conclusion, a dobutamine-induced decrease in systolic BP is not associated with fixed or reversible sestamibi defects or adverse prognosis. An increase in systolic BP, however, is associated with less fixed sestamibi defects and a tendency toward less annual event rates.

Dobutamine stress-redistribution-reinjection versus rest-redistribution thallium-201 SPECT in the assessment of myocardial viability.

The aim of this study was to evaluate the value of thallium-201 chloride (201Tl) reinjection imaging following dobutamine stress (DRi) to identify viable myocardium in comparison with a rest-redistribution 201Tl protocol (RR). The identification of viable myocardium bears important consequences for adequate selection of patients with poor left ventricular function, often unable to exercise, who are considered for revascularization. Twenty-six patients with chronic coronary artery disease and depressed left ventricular function (ejection fraction 36 +/- 10%) were studied by both DRi and RR single photon emission computed tomography (SPECT). Semi-quantitative analysis of regional 201Tl activity (5-point score) and wall motion by echocardiography using a 16-segment model was performed. Regions were classified as viable (normal/reversible/fixed moderate defects) or non-viable (fixed severe defects) and related to regional wall motion. Target heart rate was reached in 25 patients. Myocardial viability was demonstrated in 353/416 (85%) by DRi SPECT and in 346/416 (83%) by RR SPECT. The agreement between the 2 protocols was 98% with a K-value of 0.94; similar results were obtained when the analysis was limited to dyscontractile segments. In conclusion, this study demonstrates the feasibility and diagnostic value of DRi SPECT to identify viable myocardium.

In vivo imaging of pituitary tumours using a radiolabelled dopamine D2 receptor radioligand.

OBJECTIVE: Knowledge of the dopamine D2 receptor status of pituitary tumours may play a predictive role in differential diagnosis and therapeutic decisions. This study was performed to evaluate the value of pituitary dopamine D2 receptor scintigraphy with (S)-2-hydroxy-3-123I-iodo-6-methoxy-N-[(1-ethyl-2-pyrrolidinyl) methyl]benzamide (123I-IBZM) in the diagnostic evaluation of patients with pituitary tumours. DESIGN AND PATIENTS: Scintigraphy using 123I-IBZM was performed in 5 patients with PRL-secreting macroadenomas, 2 patients with PRL-secreting microadenomas, 17 patients with clinically non-functioning pituitary adenomas (NFPAs), 12 patients with GH-secreting adenomas and 1 patient with a TSH-secreting macroadenoma. RESULTS: Single-photon emission tomography (SPECT) showed significant uptake of 123I-IBZM in the pituitary region in 3/5 macroprolactinoma patients. These results closely correlated with the response of plasma PRL levels to the dopamine D2 receptor agonist quinagolide. In two scan-positive prolactinoma patients, repeated SPECTs during therapy with quinagolide showed a reduction in the pituitary uptake of 123I-IBZM. Pituitary SPECT was negative in the 2 microprolactinoma patients, who responded to quinagolide administration. In 4/17 patients with NFPA, significant uptake of the radioligand in the pituitary region was observed. In 2/3 scan-positive NFPA patients, who were treated with quinagolide, shrinkage of the pituitary tumours was observed. Treatment with quinagolide resulted in stabilization of tumour growth in the other scan-positive patients. Four out of 17 patients with NFPA and a negative SPECT were treated with quinagolide. Tumour growth was observed in 1 patient, and tumour size did not change in the other 3 patients. The pituitary region of none of the 12 acromegaly patients showed significant uptake of 123I-IBZM. Sensitivity of the GH-secreting adenomas to quinagolide was demonstrated in 8/12 patients in vivo by an acute test, and in 6/9 of the tumours in vitro. Pituitary SPECT was negative in the patient with the TSH-secreting macroadenoma and this tumour also showed no sensitivity to quinagolide in vivo or in vitro. CONCLUSIONS: We conclude that 123I-IBZM is a ligand for in vivo imaging of dopamine agonist- sensitive macroprolactinomas, but not for microprolactinomas or GH-secreting adenomas. The technique potentially provides a means of predicting the dopamine agonist-responses of non-functioning pituitary adenomas in vivo.

Dobutamine thallium-201 SPECT imaging for assessment of peri-infarction and remote myocardial ischemia.

UNLABELLED: This study assessed the value of dobutamine 201Tl scintigraphy for detecting significant disease of infarct-related and remote coronary arteries in myocardial infarction patients. METHODS: Dobutamine (up to 40 micrograms/kg/min)/atropine (up to 1 mg) stress test in conjunction with stress-reinjection 200Tl SPECT was performed in 71 symptomatic patients with left ventricular dysfunction > 3 mo after myocardial infarction. Ischemia was defined as reversible perfusion defects. RESULTS: Significant coronary artery stenosis (> or = 50% luminal diameter stenosis) was detected in all patients. Sensitivity, specificity and accuracy of regional ischemia for the diagnosis of remote coronary artery stenosis were 74% (95% Cl 63-86), 80% (Cl 70-90) and 76% (Cl 65-87), respectively. Those for infarct-related artery stenosis were 71% (Cl 60-81), 83% (Cl 75-92) and 72% (Cl 61-82), respectively. Ischemic perfusion score was higher in patients with multiversus single-vessel disease (1056 +/- 1021 versus 423 +/- 633, p < 0.01). CONCLUSION: Dobutamine thallium scintigraphy is valuable for assessing the extent of coronary stenosis on the basis of reversible hypoperfusion in symptomatic patients late after myocardial infarction.

Altered myocardial perfusion during dobutamine stress testing in silent versus symptomatic myocardial ischaemia assessed by quantitative MIBI SPET imaging.

The aim of the study was to compare the extent and severity of reversible underperfusion in silent versus painful myocardial ischaemia during the dobutamine stress test. A consecutive series of 85 patients with significant coronary artery disease and reversible perfusion defects on technetium-99m methoxyisobutylisonitrile single-photon emission tomography performed at rest and during high-dose dobutamine stress (up to 40 microg kg-1 min-1) were studied. The left ventricle was divided into six segments. An ischaemic perfusion score was derived quantitatively by subtracting the rest from the stress defect score. Patients with multivessel disease had a higher ischaemic score (610+/-762 vs 310+/-411, P<0. 05) and a higher number of reversible perfusion defects (2.1+/-1.2 vs 1.1+/-0.8, P<0.01) than patients with single-vessel disease. Typical angina occurred in 37 patients (44%) during the test. There was no significant difference between patients with and patients without angina with respect to age, gender, peak rate-pressure product, prevalence of previous myocardial infarction, diabetes mellitus, multivessel disease or number of stenotic coronary arteries. Stress, rest and ischaemic scores as well as the number and distribution of reversible defects were not different in patients with and patients without angina. Patients with angina more frequently had a history of typical angina before the test (43% vs 17%, P<0.01) and ST-segment depression during the test (54% vs 25%, P<0.01). It is concluded that in patients with coronary artery disease and ischaemia detected by dobutamine scintigraphy, the extent and severity of coronary artery disease and myocardial perfusion abnormalities are similar with or without angina during stress testing.

Prediction of recovery of myocardial dysfunction after revascularization. Comparison of fluorine-18 fluorodeoxyglucose/thallium-201 SPECT, thallium-201 stress-reinjection SPECT and dobutamine echocardiography.

OBJECTIVES: We compared three techniques to predict functional recovery after revascularization. BACKGROUND: Recently, fluorine-18 (F-18) fluorodeoxyglucose in combination with single-photon emission computed tomography (SPECT) has been proposed to identify viable myocardium, Thallium-201 reinjection and low dose dobutamine echocardiography are used routinely for this purpose. METHODS: Seventeen patients (mean [+/- SD] left ventricular ejection fraction 36 +/- 11%) were studied. Regional and global ventricular function were evaluated before and 3 months after revascularization by echocardiography and radionuclide ventriculography, respectively. Myocardial F-18 fluorodeoxyglucose uptake (during hyperinsulinemic glucose clamping) was compared with rest perfusion assessed with early thallium-201 SPECT. On a separate day, low dose dobutamine echocardiography and post-stress thallium-201 reinjection SPECT were simultaneously performed. RESULTS: The sensitivities for F-18 fluorodeoxyglucose/thallium-201, thallium-201 reinjection and low dose dobutamine echocardiography to assess recovery were 89%, 93% and 85%, respectively; specificities were 77%, 43% and 63%, respectively. Stepwise logistic regression indicated that F-18 fluorodeoxyglucose/ thallium-201 was the best predictor. In hypokinetic segments, the combination of F-18 fluorodeoxyglucose/thallium-201 and low dose dobutamine echocardiography was the best predictor. Global function improved (left ventricular ejection fraction increased > 5%) in 6 patients and remained unchanged in 11. All three techniques correctly identified five of six patients with improvement. Fluorine-18 fluorodeoxyglucose/thallium-201 identified all patients without improvement; low dose dobutamine echocardiography identified 9 of 11 without improvement; and thallium-201 reinjection identified 6 of 11 patients without improvement. CONCLUSIONS: Fluorine-18 fluorodeoxyglucose/thallium-201 SPECT was superior to the other techniques in assessing functional recovery. Integration of metabolic and functional data is necessary, particularly in hypokinesia, for optimal prediction of improvement of regional function.

Prognostic value of dobutamine-atropine stress technetium-99m sestamibi perfusion scintigraphy in patients with chest pain.

OBJECTIVES: This study investigated the prognostic value of dobutamine-atropine technetium-99m (Tc-99m) sestamibi single-photon emission computed tomographic (SPECT) myocardial perfusion imaging. BACKGROUND: Dobutamine-atropine Tc-99m sestamibi SPECT imaging is an accurate method for the detection of coronary disease. However, the prognostic value of this stress modality has not been assessed. METHODS: Three hundred ninety-two consecutive patients with chest pain (mean [+/- SD] age 60 +/- 12 years; 220 men, 190 with a previous myocardial infarction) underwent a dobutamine-atropine Tc-99m sestamibi SPECT scintigraphic study. Patients were followed up for 22 +/- 13 months to determine the univariate and multivariate variables associated with hard cardiac events (cardiac death, nonfatal myocardial infarction), to define their event-free survival and to determine whether the extent and severity of reversible perfusion defects correlated with events. RESULTS: Forty-four patients (11%) had hard cardiac events. Multivariate models demonstrated that older age (odds ratio [OR] 2.1, 95% confidence interval [CI] 1.0 to 4.4), history of heart failure (OR 2.6, 95% CI 1.3 to 5.2), abnormal sestamibi scan results (OR 10.0, 95% CI 2.3 to 43.0) and reversible perfusion defects (OR 3.2, 95% CI 1.6 to 6.4) had independent predictive value. Patients without perfusion defects, with fixed defects alone, reversible defects alone and fixed plus reversible defects had annual hard cardiac event rates of 0.8%, 6.8%, 8.1% and 11.6%, respectively. Patients with increasing reversible defect scores had increasing annual event rates of 2.1%, 5.0%, 5.5%, 13.0% and 14.6%, respectively. CONCLUSIONS: Dobutamine-atropine stress Tc-99m sestamibi SPECT imaging provides excellent prognostic information. The single most important independent predictor for future hard cardiac events is an abnormal pattern, and a reversible defect provides additional, independent prognostic information. Moreover, the extent and severity of reversible defects are major determinants for prognosis.

Accurate measurement of left ventricular ejection fraction by three-dimensional echocardiography. A comparison with radionuclide angiography.

BACKGROUND: Three-dimensional echocardiography is a promising technique for calculation of left ventricular ejection fraction, because it allows its measurement without geometric assumptions. However, few data exist that study its reproducibility and accuracy in patients. METHODS AND RESULTS: Twenty-five patients underwent radionuclide angiography and three-dimensional echocardiography that used the rotational technique (2 degrees interval and ECG and respiratory gating). Left ventricular volume and ejection fraction were calculated by use of Simpson's rule at a slice thickness of 3 mm. Analyses were performed to define the largest slice thickness required for accurate calculation of left ventricular volume and ejection fraction. Three-dimensional echocardiography showed excellent correlation with radionuclide angiography for calculation of left ventricular ejection fraction (mean +/- SD, 38.9 +/- 19.8 and 38.5 +/- 18.0, respectively; r = .99); their mean difference was not significant (0.03 +/- 0.17; P = .3), and they had a close limit of agreement (-0.385, 0.315). Intraobserver variability for radionuclide angiography and three-dimensional echocardiography was 4.2% and 2.6%, respectively, whereas interobserver variability was 6.2% and 5.3%, respectively. There was no significant difference between left ventricular volume and ejection fraction calculated at a slice thickness of 3 mm and that calculated at different slice thicknesses up to 24 mm. However, the standard deviation of the mean difference showed a stepwise increase, particularly at thicknesses > 15 mm. At a slice thickness of 15 mm, the probability of three-dimensional echocardiography to detect > or = 6% difference in ejection fraction was 80%. CONCLUSIONS: Three-dimensional echocardiography has excellent correlation with radionuclide angiography for calculation of left ventricular ejection fraction in patients and has an observer variability similar to that of radionuclide angiography. We recommend the use of a 15-mm-thick slice for accurate and rapid measurement of left ventricular volume and ejection fraction.

Prognostic significance of normal dobutamine-atropine stress sestamibi scintigraphy in women with chest pain.

To evaluate the prognostic value of normal dobutamine-atropine technetium-99m sestamibi single-photon emission computed tomography (SPECT) perfusion imaging in women with chest pain and inability to perform an adequate exercise test, 80 women with a normal scintigram were followed up for 23 +/- 13 months. Mean age of the patients was 61 +/- 12 years. Nine patients (11%) had a low probability (< 10%) of coronary artery disease, 43 (54%) had an intermediate probability (10% to 80%) of disease, and 28 (35%) had a high probability (>80%) of disease (including 19 patients with known coronary artery disease). During follow-up, no major cardiac events (cardiac death or nonfatal myocardial infarction) occurred. One patient with known coronary disease underwent coronary bypass surgery after 3 months, and 1 patient with a 91% pretest likelihood of coronary disease underwent coronary angioplasty after 7 months. Thus, the overall incidence of (soft) cardiac events during the follow-up period was 2 of 80 patients, or 1.3%/year. It is concluded that normal dobutamine-atropine technetium-99m sestamibi SPECT perfusion imaging in women with chest pain implies an excellent prognosis, even in women with high pretest likelihood of coronary disease.

Dobutamine-induced hypoperfusion without transient wall motion abnormalities: less severe ischemia or less severe stress?

OBJECTIVES: This study sought to compare the clinical characteristics, hemodynamic response and severity of ischemia in patients with coronary artery disease and reversible perfusion defects on dobutamine 2-methoxy isobutyl isonitrile (MIBI) single-photon emission computed tomography (SPECT) with or without transient wall motion abnormalities. BACKGROUND: The occurrence of reversible perfusion defects without concomitant wall motion abnormalities in patients with coronary artery disease was attributed to less severe ischemia. However, little data are available to support this observation. METHODS: Fifty-four consecutive patients with significant coronary artery disease and reversible perfusion defects on dobutamine (up to 40 micrograms/kg body weight per min) MIBI SPECT were studied (mean [+/- SD] age 59 +/- 11 years; 38 men, 16 women). All patients underwent simultaneous echocardiography. The myocardium was divided into six matched segments, and ischemic perfusion score was quantitatively derived in myocardial segments with reversible defects. RESULTS: New or worsening wall motion abnormalities occurred in 40 patients (74%) (group A) and were absent in 14 (26%) (group B). There was no significant difference between the two groups with respect to age, previous myocardial infarction, number of abnormal coronary arteries (1.8 +/- 0.8 vs. 1.6 +/- 0.9), number of reversible perfusion defects (1.6 +/- 0.9 vs. 1.8 +/- 0.7) or ischemic perfusion score (412 +/- 750 vs. 526 +/- 553). Patients in group A had a higher prevalence of male gender (80% vs. 43%, p < 0.01), higher peak systolic blood pressure (147 +/- 30 vs. 127 +/- 31 mm Hg, p < 0.05), higher peak rate-pressure product (19,632 +/- 4,081 vs. 16,939 +/- 4,344, p < 0.01) and a higher prevalence of angina (53% vs. 14%) and ST segment depression (55% vs. 14%) than group B (p < 0.05 for both). CONCLUSIONS: In patients with coronary artery disease and ischemia on dobutamine MIBI SPECT, the absence of transient wall motion abnormalities is associated with a similar extent and severity of reversible perfusion defects, a lower stress rate-pressure product and a higher prevalence of female gender than patients with transient wall motion abnormalities. Mechanically silent ischemia should not be regarded as a marker of less severe ischemia on myocardial perfusion scintigraphy.

Evaluation by quantitative 99m-technetium MIBI SPECT and echocardiography of myocardial perfusion and wall motion abnormalities in patients with dobutamine-induced ST-segment elevation.

ST-segment elevation during exercise testing has been attributed to myocardial ischemia and wall motion abnormalities (WMA). However, the functional significance of ST-segment elevation during dobutamine stress testing (DST) has not been evaluated in patients referred for diagnostic evaluation of myocardial ischemia. DST (up to 40 micrograms/kg/min) with simultaneous echocardiography and technetium-99m sestamibi single-photon emission computed tomography (SPECT) was performed in 229 consecutive patients with suspected myocardial ischemia who were unable to perform an adequate exercise test; 127 (55%) had a previous acute myocardial infarction (AMI). ST elevation was defined as > or = 1 mm new or additional J point elevations with a horizontal or upsloping ST segment lasting 80 ms. Reversible perfusion defects on SPECT and new or worsening WMA during stress on echocardiography were considered diagnostic of ischemia. ST elevation occurred in 40 patients (17%) during the test; 34 of them (85%) had previous AMI. All patients with ST-segment elevation had abnormal scintigrams (fixed or reversible defects, or both) and abnormal wall motion (fixed or transient defect, or both) at peak stress. In patients who had ST elevation and no previous AMI (n = 6), ischemia was detected in all by echocardiography and in 5 (83%) by SPECT. In patients with previous AMI, the prevalence of ischemia was not different with or without ST elevation (53% vs 43% by echocardiography and 53% vs 48% by SPECT, respectively). Baseline regional wall motion score in the infarct zone was higher in patients with ST elevation.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative angiographic measurements of isolated left anterior descending coronary artery stenosis. Correlation with exercise echocardiography and technetium-99m 2-methoxy isobutyl isonitrile single-photon emission computed tomography.

OBJECTIVES: This study sought to assess the value of quantitative coronary arteriography in predicting an ischemic response at exercise echocardiography and technetium-99m 2-methoxy isobutyl isonitrile (mibi) single-photon emission computed tomography (SPECT) in patients with single-vessel disease of the left anterior descending coronary artery. BACKGROUND: The relation between severity of coronary stenosis and ischemic response to exercise echocardiography and perfusion scintigraphy in patients with single-vessel left anterior descending coronary artery disease is not well established. METHODS: Thirty-one patients without a previous myocardial infarction who had isolated stenosis of varying degrees in the proximal or midportion of the left anterior descending coronary artery were studied. Quantitative arteriographic analysis was used for measurements of percent diameter stenosis and minimal lumen diameter. Exercise-induced wall motion abnormalities by echocardiography and transient perfusion defects by mibi SPECT were considered a positive response. The analysis of sensitivity/specificity and receiver operating characteristic curves was applied to establish the diagnostic power of quantitative coronary arteriography to predict an ischemic response to exercise echocardiography and mibi SPECT: RESULTS: The "best" angiographic cutoff values for predicting a positive exercise echocardiographic and scintigraphic response were similar (diameter stenosis 52%, minimal lumen diameter 1.12 mm for echocardiography; diameter stenosis 49%, minimal lumen diameter 1.20 mm for SPECT). However, the sensitivity/specificity at the cross point was slightly higher (even if not statistically significant) for echocardiography than for SPECT, both for diameter stenosis (81% vs. 67%) and minimal lumen diameter (81% vs. 74%), suggesting that quantitative coronary arteriographic measurements are more closely related to echocardiographic than scintigraphic exercise test results. CONCLUSIONS: The functional significance of a proximal/mid-left anterior descending coronary artery stenosis measured by quantitative coronary arteriography is slightly better related to echocardiographic than scintigraphic markers of exercise-induced myocardial ischemia.

Prediction of improvement of regional left ventricular function after surgical revascularization. A comparison of low-dose dobutamine echocardiography with 201Tl single-photon emission computed tomography.

BACKGROUND: Although both 201Tl scintigraphy and low-dose dobutamine echocardiography (LDDE) have been proposed as effective methods of assessing myocardial viability, their relative efficacies are unknown. The aim of the present study was to compare the two imaging techniques in the prediction of improvement of regional left ventricular (LV) function after surgical revascularization. METHODS AND RESULTS: Thirty-eight patients with severe chronic LV dysfunction (ejection fraction < or = 40%, one or more akinetic [Ak] or severely hypokinetic [SH] segments on resting echocardiogram) who underwent uncomplicated coronary artery bypass graft surgery were studied with simultaneous dobutamine stress echocardiography and poststress reinjection 201Tl single-photon emission computed tomography (SPECT) before surgery. The Ak or SH segments were considered viable by LDDE when wall thickening improved during the infusion of 10 micrograms.kg-1 min 1 dobutamine. Scintigraphic definition of viability was the presence of normal 201Tl uptake, totally reversible defect, partially reversible defect, or moderately severe fixed defect. The postoperative improvement of dyssynergic segments was determined with a rest echocardiogram 3 months after surgery. Of 608 LV segments, 169 were classified as Ak and 51 as SH on resting preoperative echocardiography. Of these, 170 were successfully revascularized. Wall motion during LDDE improved in 33 severely dyssynergic segments and was more frequent in SH than in Ak segments (19 of 44 versus 14 of 126, P < .0001). Viability was detected by 201Tl SPECT criteria in 103 SH or Ak segments. Thirty-two of the 33 segments from LDDE responders were judged viable on 201Tl SPECT, whereas 201Tl viability was also detected in 71 of 137 segments from LDDE nonresponders. The sensitivity and the specificity for the prediction of postoperative improvement of segmental wall motion were 74% (95% confidence interval [CI], 67% to 81%) and 95% (95% CI, 92% to 98%) by LDDE and 89% (95% CI, 84% to 94%) and 48% (95% 40% to 56%) by 201Tl SPECT, respectively. Positive predictive value of LDDE was higher than that of 201Tl SPECT (85%, [95% CI, 80% to 90%] versus 33% [95% CI, 26% to 40%]). Thirty-six patients had angina before and only 1 had angina 3 months after revascularization. High-dose dobutamine echocardiography demonstrated significant reduction in stress-induced ischemia (new or worsening of preexisting wall motion abnormalities) after surgery (from 163 to 23 LV segments). CONCLUSIONS: In patients with severe chronic LV dysfunction, LDDE is a good predictor of the improvement of dyssynergic segments after revascularization. Because 201Tl SPECT overestimates the probability of postoperative improvement of dyssynergic segments, LDDE should be the preferred imaging technique for preoperative assessment of these patients.