Showing papers by "Simone Maurea published in 1995"

Enhanced Detection of Viable Myocardium by Technetium-99m-MIBI Imaging after Nitrate Administration in Chronic Coronary Artery Disease

Abstract: The aim of this study was to assess whether nitrate administration improves the imaging capabilities of 99m Tc-MIBI tomography in detecting viable myocardium in coronary artery disease (CAD). Methods : Thirty-one patients with angiographically proven CAD and chronic LV dysfunction (ejection fraction 39% ± 9%) underwent two 99m Tc-MIBI studies on separate days : one under rest conditions and the other after nitroglycerine (0.005 mg/kg per os) administration. Within 1 wk, all patients also underwent rest-redistribution 201 Tl imaging. Eight patients were also studied by echocardiography before and 5 ± 3 mo after coronary revascularization. Results : On resting 99m Tc-MIBI images, 302 segments had normal uptake, 183 segments had moderately reduced uptake and 197 had severely reduced uptake. Of the segments with severely reduced uptake, 54 (27%) had increased uptake after nitroglycerine and were viable on 201 Tl images. Of the 143 (73%) segments with severely reduced 99m Tc-MIBI uptake and no change after nitroglycerine, 81% were nonviable on 201 Tl images. In the eight patients studied before and after revascularization, 87% of segments with reversible 99m Tc-MIBI defects and abnormal LV function demonstrated functional recovery after revascularization, whereas 89% of segments with irreversible 99m Tc-MIBI defects did not. Conclusion : In patients with chronic ischemic LV dysfunction, nitrate administration improved the detection of severely hypoperfused but still viable myocardium on 99m Tc-MIBI images.

Technetium-99m-tetrofosmin imaging of differentiated mixed thyroid cancer

Abstract: This report describes the accurate localization of metastatic lesions in a patient with differentiated mixed thyroid cancer using 99m Tc-tetrofosmin imaging. A 66-yr-old women with a cytological diagnosis of follicular thyroid cancer associated with a large amount of goiter changes was studied by 99m Tc-tetrofosmin total-body scintigraphy. No significant tetrofosmin uptake was observed in the thyroid nodules, which mainly showed goiter abnormalities. Abnormal increased tetrofosmin uptake, however, was found in metastatic tumor lesions located in the cervical and dorsal spine as well as in the left lower chest wall and lungs. In conclusion, 99m Tc-tetrofosmin, a new radiopharmaceutical proposed for myocardial perfusion imaging, may be useful in patients with thyroid cancer.

Impaired Left Ventricular Diastolic Filling in Patients with Acromegaly: Assessment with Radionuclide Angiography

Abstract: UNLABELLED Acromegaly is associated with increased cardiac morbidity and mortality, but it is not clear whether this is the result of a specific disease of heart muscle or of increased incidence of hypertension. METHODS Twenty-six patients with acromegaly (11 male and 15 female, mean age 45 +/- 13 yr) and 15 and 12 age- and sex-matched normal controls underwent high temporal resolution radionuclide angiography and two-dimensional echocardiography at rest. RESULTS Normal controls and patients with acromegaly did not differ with respect to heart rate, ejection fraction, time to end systole, peak ejection rate (PER) and time to PER. In contrast, peak filling rate (PFR), normalized to end diastolic volume (EDV), or stroke volume (SV), or expressed as the ratio of PFR-to-PER was reduced (p < 0.01), time to PFR (TPFR) was prolonged (p < 0.01), and echocardiographic left ventricular mass index was higher (p < 0.001) in patients with acromegaly compared to normals. Patients with acromegaly were divided in normotensives (group 1, n = 17) and hypertensives (group 2, n = 9). Although left ventricular mass index was significantly (p < 0.01) higher in group 2 compared to group 1, PFR and time to PFR were not different between the two groups of acromegalic patients. In the entire group of patients with acromegaly significant relationships between left ventricular mass index and EDV/s (r = -0.56, p < 0.01), SV/s (r = -0.73, p < 0.001), and PFR/PER (r = -0.61, p < 0.001) were observed. CONCLUSION Patients with acromegaly have impaired left ventricular diastolic filling at rest related to greater left ventricular mass index even in the absence of systemic hypertension.

Comparison of labeled MIBG and somatostatin analogs in imaging neuroendocrine tumors.

Abstract: In 10 patients with histologically proven neuroendocrine tumors (4 carcinoids, 4 pheochromocytomas, 1 medullary thyroid cancer and 1 Merkel tumor) the results of radiolabeled metaiodobenzylguanidine (MIBG) and somatostatin analogs were compared. A total of 24 tumor lesions was detected on standard imaging studies. MIBG scintigraphy correctly localized 12 (50%) of these lesions which were observed in 5 patients (4 with pheochromocytoma and 1 with carcinoid tumor). Scintigraphy using labeled somatostatin analogs correctly localized 21 (87%) lesions which occurred in 8 patients (4 with carcinoid, 2 with pheochromocytoma, 1 with medullary thyroid cancer and 1 with Merkel tumor). Concordant scintigraphic results were obtained in 1 patient with carcinoid and 2 with pheochromocytoma. In conclusion, although this series was limited, our results suggest that MIBG is more accurate than somatostatin analogs in imaging pheochromocytoma. Conversely, somatostatin analogs are more accurate than MIBG in detecting other neuroendocrine tumors such as carcinoids.

The diagnosis of nonfunctioning pheochromocytoma. The role of I-123 MIBG imaging.

Abstract: A patient with an asymptomatic nonsecreting left adrenal pheochromocytoma concentrated I-123 MIBG. lodine-123 MIBG scintigraphy showed abnormal uptake in the left adrenal bed. The authors conclude that I-123 MIBG imaging may allow the in vivo diagnosis of nonfunctioning pheochromocytomas when there is no clinical evidence of disease and other laboratory measurements are not helpful for tumor diagnosis

Assessment of systolic wall thickening using technetium-99m methoxyisobutylisonitrile in patients with coronary artery disease: relation to thallium-201 scintigraphy with re-injection

Abstract: The results of resting planar ECG-gated technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) imaging were compared with those of thallium-201 (TI) reinjection after exercise-redistribution scintigraphy in 20 patients (19 men, 1 woman, mean age 53±10 years) with angiographically proven coronary artery disease. Eight normal subjects (seven men, one woman, mean age 50±8 years) constituted the control group. In these subjects, only resting99mTc-MIBI imaging was performed. The standardized percent count increase from end-diastole to end-systole was calculated as an index of wall thickening in 13 segments for each study. Regional wall thickening index (WTI) and99mTc-MIBI uptake were significantly different (P<0.05) among segments classified as normal, reversible defects, irreversible defects with increased tracer uptake after re-injection (Re+) or irreversible defects with unchanged tracer uptake after re-injection (Re-) on TI imaging. Furthermore, WTI and99mTc-MIBI uptake were significantly higher (P<0.05) in Resegments with moderate reduction of T1 uptake (≥50% of peak activity) than in Re- segments with severe reduction of TI uptake (<50% of peak activity). A significant relationship between WTI and the results of TI scintigraphy was observed (rho=0.71,P<0.0001). The percentage of Re- segments with severe reduction of WTI was significantly higher compared to Re+ segments (64% vs 3%,P<0.01). Furthermore, compared with moderate Re- segments, a significantly higher percentage of severe Re- segments showed a severe reduction of WTI (86% vs 48%,P<0.01). Our data document a close relationship between99mTc-MIBI regional wall thickening, myocardial perfusion and TI uptake after reinjection. The results of this study suggest that regional WTI decreased significantly as myocardial perfusion decreased. In addition, regional wall thickening was preserved in segments with exercise-induced ischaemia and enhanced TI uptake after re-injection.

Scintigraphic characterization of expansive lesions located in the adrenals. Comparison with magnetic resonance imaging

Abstract: In this study, 35 patients (11 men and 24 women, mean age 47 +/- 16 years) with unilateral adrenal masses underwent nor-cholesterol (nor-Chol) (n = 11), metaiodobenzylguanidine (MIBG) (n = 15) or nor-Chol and MIBG (n = 9) radionuclide studies. In all patients Magnetic Resonance (MR) adrenal imaging was also performed. In 19 (54%) patients, no laboratory abnormalities of adrenal function were observed. In the other 16 (46%) patients, adrenal hyperfunction was found. In 21 lesions, histology showed 10 pheochromocytomas (Pheos), 6 adenomas, 3 metastases, 1 cyst and 1 nodular focal liver hyperplasia. In the remaining 14 lesions, increased cortisol (n = 4) or aldosterone (n = 2) levels and/or intense nor-Chol uptake (n = 14) were considered suggestive of adenoma. Diagnostic accuracy of both nor-Chol and MIBG radionuclide studies in correctly identifying adenoma or Pheos was 100%. Conversely, qualitative MR signal intensity (SI) analysis on T2-weighted images did not allow to accurately distinguish lesions of different nature. In particular, 10 Pheos, 8 adenomas, 3 mestastasis and 1 cyst clearly showed on T2-weighted images higher SI than the liver; 5 adenomas had a slight higher SI; the remaining lesions (7 adenomas and 1 liver hyperplasia) exhibited low SI. In conclusion, adrenal scintigraphy using nor-Chol or MIBG allows to identify adenomas and Pheos, respectively. Conversely, qualitative MR SI analysis cannot differentiate different adrenal lesion (Pheos, adenoma, metastasis and cyst) and yields heterogeneous results in adenomas.

[Morpho-functional diagnostic imaging in the assessment of viable myocardium in patients with ischemic heart disease. Correlations between myocardial perfusion and regional function of the left ventricle].

Abstract: Forty patients (38 men and 2 women, mean age 56 +/- 9 years) with angiographic evidence of coronary artery disease underwent 201Thallium myocardial scintigraphy and two-dimensional echocardiography. 201Thallium uptake and echocardiographic regional ventricular function were studied in corresponding myocardial segments. On exercise-redistribution 201Thallium imaging, 308 segments (51% of the total) had normal Thallium uptake, 48 (8%) exhibited reversible defects and 244 (41%) irreversible defects. Of the latter 244 segments with irreversible defects, 114 (47%) exhibited increased tracer uptake (Re+) and 130 (53%) remained unchanged (Re-) after 201Thallium reinjection at rest. Regional ventricular function was significantly better in the segments with normal Thallium uptake than in the segments with reversible or irreversible defects (p < 0.001). Furthermore, the segments with irreversible defects Re- had impaired regional function compared to the segments with irreversible defects Re+ (p < 0.001). Coronary artery stenosis was significantly more severe in the segments with irreversible defects Re- (93 +/- 16%) than in those with reversible defects (81 +/- 20%) and with irreversible Re+ defects (80 +/- 20%) (both p < 0.001). In conclusion, in coronary artery disease patients, exercise-redistribution 201Thallium cardiac imaging with reinjection at rest can identify severely ischemic but still viable myocardium and may be particularly useful in the prognosis of such patients.