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U Meldolesi

Publications and source records attributed to U Meldolesi.

At least 19 recordsLinked to original sources
PubMed1991

Comparison of tomographic and planar imaging for the evaluation of thrombolytic therapy in acute myocardial infarction using pre- and post-treatment myocardial scintigraphy with technetium-99m sestamibi.

Pre- and post-treatment myocardial scintigraphy with technetium-99m hexakis 2-methoxy-isobutyl-isonitrile (Tc-99m sestamibi) was performed in patients who underwent thrombolytic therapy for acute myocardial infarction comparing planar imaging and single-photon emission computed tomography (SPECT). Twenty-one patients were injected with Tc-99m sestamibi before thrombolytic treatment. SPECT and planar imaging were acquired after completion of the treatment. The scintigraphy was repeated 5 days later in 20 subjects. Planar and SPECT studies were evaluated using an uptake score. Patients were divided according to the status of the infarct-related vessel (patent in 13 patients, group 1, and occluded in seven, group 2) and to the presence of functional recovery in serial echocardiographic controls (present in 10 patients, group A, and absent in 10, group B). The scintigraphic defect extent in the 5-day images correlated with the enzymatic infarct size: SPECT: r = 0.75, p less than 0.0002; planar: r = 0.68, p less than 0.002. The decrease of the uptake defects correlated with the reduction of the left ventricular wall asynergy (admission versus 1 month echocardiogram): SPECT: r = 0.92, p less than 0.000001; planar: r = 0.82, p less than 0.00001. The percent decrease of the uptake defects was significantly higher in patients in group 1 and group A compared with group 2 and, respectively, group B--SPECT: group 1: 51.4 +/- 27.7 versus group 2: 13.1 +/- 8.6, p less than 0.02; group A: 64.2 +/- 15.3 versus group B: 11.9 +/- 8.1, p less than 0.0002; planar group 1: 41 +/- 30.4 versus group 2: 7.7 +/- 6.2, p less than 0.05; group A: 52.5 +/- 24.3 versus group B: 6.1 +/- 6, p less than 0.0002. This study confirms the reliability of pre- and post-treatment myocardial scintigraphy with Tc-99m sestamibi for evaluating the outcome of thrombolytic treatment in myocardial infarction. The results seems slightly more accurate using SPECT, but a simple three-view planar study also gives useful data.

Adult↗
PubMed1991

An analysis of the arterial input curve for technetium-99m-HMPAO: quantification of rCBF using single-photon emission computed tomography.

Arterial radioactivity content after the intravenous administration of HMPAO in seven human subjects was analyzed. Arterial sampling of 99mTc-HMPAO was performed on each subject over a 25-min period postinjection. The lipophilic fraction of the tracer present in the blood was rapidly extracted with octanol. An analysis of the time course of the extracted and nonextracted octanol fractions was performed in order to calculate the arterial input of the tracer available for brain extraction. HMPAO net regional brain clearances were then calculated and compared with rCBF values obtained in the same patients using 99mTc-microspheres injected into the left ventricle of the heart. HMPAO brain clearances were 0.41 +/- 0.01 and 0.27 +/- 0.01 ml/min/g for grey and white matter, respectively. Linear regression analysis was performed and the following result was obtained: clearance (HMPAO) = 0.07 + 0.43 . rCBF with a high significance (p less than 0.001). This equation can be used for the transformation of HMPAO clearances into rCBF values. Our study demonstrates that by using HMPAO and SPECT it is possible to obtain a quantitative estimate of rCBF in humans.

Adult↗
PubMed1990

Evaluation of technetium 99m cyclobutylpropylene amine oxime as a potential brain perfusion imaging agent for SPET.

Technetium 99m d,l-cyclobutylpropylene amine oxime (99mTc-CBPAO) has been developed as a brain-imaging agent for single photon emission tomography (SPET). 99mTc-CBPAO can be prepared using a simple labelling procedure suitable for routine clinical use. It has a high in vitro stability, as has been demonstrated by high-pressure liquid chromatography (HPLC) analysis. This shows that 3 h after labelling, less than 5% of the primary lipophilic complex which is capable of crossing the blood-brain barrier (BBB) converts to a secondary hydrophilic complex. Brain uptake (% dose/g wet tissue) of 99mTc-CBPAO, determined at 5 and 30 min after injection in two groups of six adult male Sprague-Dawley rats, was found to be 0.74 +/- 0.06 and 0.73 +/- 0.13 (mean +/- SD), respectively. These values are not significantly different from those obtained repeating the experiment with 99mTc-labelled hexamethylpropylene amine oxime (99mTc-HMPAO) (0.72 +/- 0.15 at 5 min and 0.88 +/- 0.24 at 30 min after injection). Since the rat brain uptake of 99mTc-CBPAO remained unchanged for a period of time suitable for tomographic study, the comparison of the two tracers was extended to two groups of ten patients. The latter were affected by neurological and psychiatric disorders and were studied with SPET. Human brain uptake (% dose/cc cortical grey matter) of 99mTc-CBPAO and 99mTc-HMPAO were 3.04 +/- 0.57 and 4.22 +/- 0.46 (mean x 10(-3) +/- SD x 10(-3), respectively, with a 32% significant difference. In two other groups of five patients, the first transit time-activity curves of the two tracers were compared.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

A brain phantom for studying contrast recovery in emission computerized tomography.

A brain phantom is described that is characterized by a high anatomical definition and by the possibility of varying the internal contrast with the use of a single radioactive solution. The experimental work was done with a single-photon emission computerized tomographic (SPET) rotating camera. The phantom was used to study the contrast recovery of both the filtered back-projection and an iterative reconstruction algorithm. Moreover, it was also used to find a cross-calibration factor between activity concentrations in the SPET slices and an external reference.

Algorithms↗
PubMed1990

Single photon emission computed tomography with technetium-99m hexakis 2-methoxyisobutyl isonitrile in acute myocardial infarction before and after thrombolytic treatment: assessment of salvaged myocardium and prediction of late functional recovery.

Single photon emission computed tomography (SPECT) with technetium-99m hexakis 2-methoxyisobutyl isonitrile was investigated as a method to evaluate the results of intravenous thrombolytic treatment in 14 patients (11 men and 3 women) with acute myocardial infarction admitted to the coronary care unit within 4 h of the onset of symptoms. All patients received an injection of 740 MBq of the tracer before starting the thrombolytic therapy, and isonitrile tomography was performed 3 to 4 h later. The tomographic study was repeated 5 days after the acute event. The results of thrombolytic treatment were independently evaluated taking into account the clinical, electrocardiographic (ECG) and enzymatic data and the findings of left ventricular and coronary angiography. Furthermore, all patients were studied with two-dimensional echocardiography on admission, 5 days later and 1 month later. The site and extent of the perfusion defects on admission scintigraphy were consonant with the ECG and echocardiographic findings. A good correlation could be established between the 5 day scintigraphic estimate of infarct dimension and the enzymatic infarct size (r = 0.907, p less than 0.00002). The comparison between pre- and postthrombolytic treatment images enabled the identification of successful and unsuccessful reperfusion even in patients whose other noninvasive findings were inconclusive. Finally, the reduction in defect size predicted late functional improvement that was demonstrated by echocardiography performed 1 month later (r = 0.89, p less than 0.00005). The results of the study suggest the feasibility and the possible usefulness of isonitrile tomography in demonstrating the presence and size of myocardial damage and in assessing the extent of myocardial salvage after thrombolytic therapy in acute myocardial infarction.

Aged↗
PubMed1990

[Ealuation of thrombolytic treatment of acute myocardial infarct using myocardial scintigraphy with Tc-99-MIBI. Immediate results and follow-up after one year].

The aim of the study was to investigate Single Photon Emission Computed Tomography (SPECT) with technetium-99m esakis-2-methoxy isobutyl isonitrile (Tc-99m-MIBI) as a means of evaluating the results of intravenous thrombolytic treatment in patients with acute myocardial infarction. In addition, the evolution of myocardial perfusion pattern was studied. The study group included 15 patients (12 males and 3 females, mean age 57 +/- 8 years) with acute myocardial infarction admitted to the coronary care unit within 4 hours of the onset of symptoms. All patients were injected with 740 MBq of Tc-99m-MIBI before starting the thrombolytic therapy (rt-PA 100 mg i.v. in 3 hours); SPECT was performed 3 to 6 hours later. The tomographic study was repeated 5 days later. Ten patients were re-examined using Tc-99m-MIBI SPECT one year after the acute event. Taking into account the clinical, electrocardiographic and enzymatic data and the findings of two-dimensional echocardiography performed both on the fifth day and after one month, patients were divided into two groups: group A (8 patients) with probably effective reperfusion, group B (7 patients) probably unaffected by therapy. The infarct related vessel was patent in all group A patients and in 2 of the 7 patients of group B. The percent decrease in the perfusion defect size between the first and second scintigraphic studies showed a significant difference between the two groups: group A 61.2 +/- 6.8, group B 4.7 +/- 2.4% (p less than 0.002). A significant difference was also found when the results of the admission scintigraphy were compared with those of the control 1 year after: group A 80.8 +/- 8.7%, group B 20.8 +/- 13.8% (p less than 0.02). The percent decrease in the perfusion defect size between the 5-day and 1-year images was also significantly different in the two groups: group A 52.9 +/- 20.9%; group B 17.8 +/- 12% (p less than 0.02). The late perfusion improvement involved mainly the sub-epicardial layers. In conclusion, Single Photon Emission Computed Tomography with Tc-99m-MIBI clearly identified patients with effective reperfusion after thrombolytic treatment and distinguished them from subjects unaffected by therapy. Both, successfully and unsuccessfully treated patients showed a late perfusion improvement which was more evident in the successfully treated patients.

Female↗
PubMed1990

Subcortical arteriosclerotic encephalopathy: single photon emission computed tomography-magnetic resonance imaging correlation.

Regional cerebral blood flow was studied using 99mTc-HM-PAO and single photon emission computed tomography (SPECT) in five healthy subjects and in eight patients with clinical and computed tomography (CT) features of subcortical arteriosclerotic encephalopathy. All the patients and controls underwent magnetic resonance imaging (MRI). Circumscribed cortical hypoperfusion was observed in three patients, and in one case there was no evidence of cortical or sulcal alterations on MRI. In all the patients, a reduction of the white matter perfusion was found in periventricular and/or supraventricular regions. This pattern was substantially correlated with the typical white matter hyperintensities shown by MRI scans. These findings support the hypothesis that white matter hypoperfusion is the most prominent functional abnormality in subcortical arteriosclerotic encephalopathy.

Aged↗
PubMed1989

[Myocardial scintigraphy using 99m-technetium pyrophosphate in the diagnosis of acute myocardial infarct. Comparison of planar and tomographic imaging].

The aim of the study was to compare the effectiveness of planar and single photon emission computed tomography (SPECT) imaging with 99mTc-pyrophosphate in the verification of acute myocardial infarction. The study was performed on 39 patients (26 males, 13 females) aged between 41-76 years (mean 61 +/- 9) admitted to CCU for acute myocardial infarction. Patients underwent planar and SPECT imaging using a double-head-camera with a 360 degrees rotation arc within 6 days of admission. Planar images were obtained in three standard projections (anterior, LAO 45 degrees, LAO 75 degrees) with acquisitions of 500000 counts each. To obtain SPECT images ninety projections, each lasting 20 seconds, were taken; subsequently images reconstruction was performed using an iterative algorithm. Positive planar images were found in 21 out of 39 patients; SPECT images were positive in 33 patients. In "Q wave" myocardial infarctions planar images were positive in 13 out of 15 patients, whereas SPECT images were positive in all subjects; in "non-Q wave" myocardial infarctions planar images were positive in 6 out of 22 patients whereas SPECT images were positive in 16 patients (p less than 0.005); in 2 patients with left bundle branch block both planar and SPECT images were positive. A bidimensional echocardiogram was carried out on 38 patients: an alteration of left ventricular regional wall motion was present in 30 subjects; in one patient diffuse hypokinesia was present.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Prognostic value of the 131I whole-body scan in postsurgical therapy for differentiated thyroid cancer.

Seventy-two patients affected by differentiated thyroid cancer underwent whole-body scan seven days after the postsurgical thyroablative treatment with 131I. In 40 patients this scanning did not reveal any area of 131I uptake outside the residual thyroid parenchyma. During the follow-up period, no signs of functioning tumors were detected in these patients and therefore, there was no need for further therapeutic treatment with radioiodine. From this results it is legitimate to conclude that whole-body scan control can be significantly postponed without diagnostic inaccuracy for those patients whose postthyroablative scans do not reveal diffuse tumor localizations.

Adenocarcinoma↗
PubMed1977

An analysis of the diagnostic contribution of double-radiocompound renography.

The diagnostic contribution of double-radiocompound renography was tested by applying discriminant analysis to the data obtained in one group of normal subjects and in some groups of selected pathological cases which included glomerulonephritis, pyelonephritis, and hypertension. The results obtained confirm the reliability of the test and give evidence of its usefulness in diagnostic clinical work.

Adult↗
PubMed1975

The renal plasma flow and glomerular filtration rate as estimated through double radiocompound renography.

In order to estimate the renal plasma flow and glomerular filtration rate during the course of renography, a method was developed using simultaneously 131I Hippuran and 169Yb DTPA. First results obtained in a survey of approximately 200 patients are encouraging. The method permits an accurate evaluation of the renal function. In addition, by comparing the clearance rate of the two radiocompounds one can also obtain some interesting diagnostic information which can contribute usefully to the interpretation of renographic tracings and/or gamma camera sequential images.

Acute Disease↗