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Biomedical subjects

M Dondi

Publications and source records attributed to M Dondi.

At least 37 records · Page 2Linked to original sources
PubMed1994

A multicenter trial on interobserver and intraobserver reproducibility of segmental scoring of thallium-201 planar myocardial imaging before and after reinjection. Italian Group of Nuclear Cardiology.

UNLABELLED: Inter- and intraobserver reproducibility (R) of segmental 201Tl scores after stress (ST), redistribution (RD) and reinjection (RI) planar imaging were evaluated. METHODS: Images were examined from 396 patients with suspected coronary artery disease, demonstrated by means of post-ST imaging of at least one perfusion defect. To eliminate external sources of variability, the same gamma camera, acquisition protocol and computer software were used in this multicenter study. Thallium-201 images of the anterior, left anterior oblique and left lateral projections were obtained immediately, 4 hr after exercise and 30 min after the injection of additional 201Tl either on the same day or on a different day. The left ventricle was divided into 15 segments and evaluated by three independent observers, blinded to clinical data, according to a five-point scale. RESULTS: The R score for ST, RD and RI images, expressed as an intraclass correlation coefficient, was 0.76, 0.74 and 0.72, respectively. After averaging multiple observer scores, R increased to 0.91, 0.90 and 0.89, respectively. Individual observer measurement of the R score was 0.48, 0.51 and 0.32 for ST-RD, ST-RI and RD-RI image pairs, respectively, and multiple observer scores showed R increases to 0.74, 0.76 and 0.58. CONCLUSION: This qualitative scale reliably assesses the severity of 201Tl perfusion defects, particularly when multiple-observer scores are averaged. Individual observer change scores should be taken with great caution, especially in studies involving the visual evaluation of RD-RI image changes.

Coronary Disease↗
PubMed1993

A comparison of rest sestamibi and rest-redistribution thallium single photon emission tomography: possible implications for myocardial viability detection in infarcted patients.

Thirty patients (26 men, 4 women, mean age 61 +/- 8 years) who had suffered myocardial infarction 15 +/- 6 months previously, were submitted to (1) standard stress-redistribution thallium-201 single photon emission tomography (SPET), (2) rest-redistribution 201T1 SPET and (3) stress-rest technetium-99m sestamibi SPET. Uptake modifications in relation to exercise-induced defects were evaluated in a total of 390 myocardial segments. Tracer uptake was scored as normal (=0), mildly reduced (=1), apparently reduced (=2), severely reduced (=3) or absent (=4). Comparison of stress studies failed to show any statistical difference (58% segmental abnormalities with sestamibi vs 61% with thallium). Uptake abnormalities (score 1-4) were detected in 55% of the segments with sestamibi, 55% with standard thallium redistribution, 55% with early imaging after thallium injection at rest and 54% with 3-h delayed rest imaging (P = NS). Absence of tracer uptake (score = 4) under resting conditions was recorded in 75 (19%) segments with standard 201T1 redistribution, 75 (19%) with rest sestamibi, 70 (18%) with rest 201T1 imaging and 62 (16%) with rst-redistribuion 201T1 (P < 0.05 vs other imaging modalities). Thus, 3-h delayed rest thallium imaging detected reversibility of uptake defects in a significantly higher number of myocardial segments. This finding might have important implications for both tracer and technique selection when myocardial viability is the main clinical issue.

Cell Survival↗
PubMed1993

Evaluation of hypertensive patients with a solitary kidney using captopril renal scintigraphy with 99Tcm-MAG3.

The study aimed to evaluate the safety and reliability of captopril renal scintigraphy (CRS) for diagnosing functionally significant renal artery stenosis (RAS) in hypertensive patients with a solitary kidney. Radionuclide studies were carried out using 100 MBq 99Tcm-mercaptoacetyl triglycine (MAG3), 1 h after administration of 50 mg captopril, and repeated in baseline condition when abnormalities were observed in the provocative study. Scintigraphic diagnosis of RAS was based on analysis of captopril-induced changes of the radiorenographs. Overall, 12 patients with a solitary kidney were investigated, and scintigraphic results compared to angiographic findings. All five patients with positive CRS showed an RAS > 50%, whereas only one of the seven patients with negative CRS was affected by RAS. A significant fall in mean arterial pressure was recorded after captopril administration (123 +/- 12 mm Hg before versus 108 +/- 11 after), but no serious side effects were observed. Our results demonstrate that captopril-induced modifications of the renogram could effectively be used to diagnose the presence of RAS. Captopril renal scintigraphy may therefore be suggested as a reliable and safe noninvasive approach to evaluate hypertensive patients with a solitary kidney.

Adult↗
PubMed1993

Diagnosis of renovascular hypertension with captopril renal scintigraphy in a patient with a solitary kidney.

A patient with a solitary kidney due to renal agenesis and contralateral kidney perfusion impairment due to renal artery stenosis was successfully treated with percutaneous transluminal renal angioplasty. Preintervention diagnostic work-up included captopril renal scintigraphy, which was suggestive of high probability of renovascular hypertension. Scintigraphic assessment 2 mo after angioplasty failed to show any abnormality after captopril administration, a finding in line with blood pressure beneficial response to renal artery revascularization. A 12-mo follow-up confirmed cure of hypertension.

Adult↗
PubMed1993

[Color-Doppler and angioplasty in renovascular hypertension].

Renovascular hypertension is defined as a kind of hypertension secondary to altered renal perfusion with the activation of the renin-angiotensin system. Since a large number of these patients benefits from treatment--be it medical, surgical or angioplastic--a non-invasive low-cost method allowing accurate screening was looked for. Color-Doppler was employed by many authors to evaluate renovascular hypertension, for both the early diagnosis of the condition and the evaluation of treatment results in renal artery stenoses. However, the authors agree that color-Doppler cannot play a major role in the screening of renovascular hypertension due to the various qualitative and quantitative variables not being adequately codified, to the lack of a single color-Doppler method and to the difficult comparison of the results from the different units. Nevertheless, improved results are promised by technological evolution, together with the possibility to codify color-Doppler variables more easily repeatable. B-mode units with 3.5 and 5 MHz probes were employed in the thinnest subjects. In 5-25% of cases accessory renal arteries were observed. After identifying the vessel to be studied with several spatial scans, the smallest possible sample volume (usually 3-5 mm) was positioned. The normal flowmetric range was 0.07-0.1 s: it must not exceed 0.16 s, with persistence of high diastolic flow. Some authors' criteria were followed to define either stenosis or renal artery obstruction; moreover, pulsatile flow index was considered, together with the resistive index, pulsatility index and stenosis index.

Angioplasty↗
PubMed1993

[Identification of viable myocardium by 201Tl scintigraphy: a comparison of methods].

The present study was undertaken to compare four different imaging approaches to evaluate uptake defect reversibility. 24 infarcted patients underwent standard stress/redistribution 201Tl imaging (R1). Then, after reinjection of 37 MBq of 201Tl, patients were re-imaged either after 15 min (R2) 24 h later (R3). A separate rest study (R4) following a new tracer injection was done within 2-3 days. Planar images were obtained in the standard three views and subdivided into 216 segments for qualitative analysis based on a visual score. A semiquantitative analysis based upon circumferential profiles was also applied. A stress defect was found in 127 segments (58.7%). By visual inspection reperfusion was considered to occur in 32.3%, 41.7%, 33.0% and 49.6% of the cases with R1, R2, R3, and R4, respectively. The semiquantitative method showed a high reperfusion only with R1 (62%), while the other procedures proved less effective. No improvement was found with R4. Six patients (25%) showed myocardial viability that was not detected with the early reinjection technique.

Female↗
PubMed1992

Detection of renal artery stenosis by means of captopril renal scintigraphy in patients with multiple renal arteries.

Both captopril renal scintigraphy (CRS) and conventional arteriography were retrospectively evaluated in 64 patients to study CRS efficacy in hypertensive patients with multiple renal arteries (MRA). The presence of MRA was angiographically demonstrated in 9 patients, 7 unilaterally and 2 bilaterally, with a total of 11 kidneys supplied by 2 or more arteries. Overall, 25 MRA were identified and 7 were affected by stenosis of > 50%, causing a reduction of arterial supply in 5 of 11 kidneys. CRS correctly diagnosed all five ischemic kidneys (true positives) and five of six nonischemic kidneys (true negatives); in one case in which perfusion was not reduced, the CRS diagnosis was falsely positive. In the presence of MRA, CRS proved effective in identifying renal artery stenosis of > 50%, involving either one or all the MRA. This study shows that the presence of MRA is not a drawback in the evaluation of renal artery stenosis by means of CRS.

Adult↗
PubMed1992

Effects of nisoldipine in coronary artery disease: a radioisotopic approach.

The clinical, electrocardiographic, and scintigraphic effects of oral administration of nisoldipine were investigated using two separate study protocols. In the first, the acute effects of nisoldipine were evaluated by means of nuclear ventricolography and demonstrated no deleterious effects on global contractility and an amelioration of several hypokinetic segments. In the second protocol, myocardial perfusion effects were evaluated by means of tomoscintigraphy. An improvement of segmental uptake of thallium was caused by nisoldipine. The addition of atenolol markedly reduced the rate-pressure product and further improved myocardial perfusion.

Administration, Oral↗
PubMed1992

Prognostic value of captopril renal scintigraphy in renovascular hypertension.

This study evaluates the prognostic value of captopril renal scintigraphy in hypertensive patients undergoing renal artery revascularization. Preoperative studies of 51 patients were correlated with blood pressure results at 6- and 12-mo follow-up. Captopril-renal scintigraphy was carried out 1 hr after oral administration of 50 mg of captopril, using either 220 MBq of 99mTc-DTPA or 74 MBq of 99mTc-MAG3, followed by a baseline study in case of abnormal results. Evidence of amelioration or normalization in relation to captopril study was considered predictive of blood pressure control following treatment. Blood pressure response was favorable in 37 patients, but failed to show any improvement in 14. The scintigraphic test was positive in 33 patients (15 cured, 17 improved, 1 failed) and negative in 18 (3 cured, 2 improved, 13 failed). Sensitivity and specificity for renovascular hypertension was 86.5% and 93%, respectively. For blood pressure cure and improvement, the test had positive and negative predictive values of 97% and 72%, respectively. A positive preoperative captopril renal scintigraphic result is a strong predictor of hypertension curability by renal artery revascularization.

Adult↗
PubMed1992

[Renal artery stenosis. Doppler color study before and after angioplasty].

Doppler flowmetry can be successfully employed to assess arterial patency after percutaneous transluminal angioplasty (PTA). The aim of this study was to assess color Doppler sensitivity in detecting renal artery stenosis prior to percutaneous angioplasty (PTRA) and vessel patency after it. Eleven patients (7 males and 4 females) affected with renal artery stenosis, unilateral in 9 cases and bilaterally in 2, underwent color-Doppler evaluation 1 day before and 7 days after PTRA. The operator was unaware of dilatation results. A total of 13 stenoses were treated. The qualitative and quantitative parameters we employed were: a) broadening of the spectrum, b) peak systolic frequency > 4000 Hz, c) stenosis index > 50%. Before PTRA, mean systolic peak at the stenosis was 7978 (range 4050-12500 Hz), while stenosis index was 71.9% (range 48-89%). After PTRA complete recovery was observed in 5 cases, no improvement in 1 and incomplete recovery in 7. Doppler results were in agreement with those of angiography in 6/13 while partial agreement only was seen in 7/13. Our results, although obtained in a small and highly selected group of patients, would seem to support the value of color-Doppler for the follow-up of patients after PTRA.

Adult↗
PubMed1991

Captopril renal scintigraphy with 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) for detecting renal artery stenosis.

A recently developed radiopharmaceutical with favorable characteristics for renal studies, 99mTc-mercaptoacetyltriglycine (99mTc-MAG3), was employed for renal scintigraphy in the detection of renal artery stenosis (RAS) in 102 hypertensive patients who underwent renal angiography within 4 weeks of scintigraphic assessment. Renal scintigraphy was performed with 120 MBq of 99mTc-MAG3 60 min after oral administration of 50 mg captopril. Studies were evaluated for renogram shape, relative tracer uptake, time to peak counts, and parenchymal transit time. In cases of normal outcome, no further scintigraphic test was requested. In all other cases a baseline study was performed within 2 to 3 days. Where an apparent improvement was found in baseline conditions compared to the provocative test (upslope of the renogram, increased tracer uptake, and reduction of parenchymal transit time), the study was considered positive for significant RAS. At renal angiography, 48 arteries were found affected by RAS greater than 50% and 27 by RAS less than 50%. Sensitivity and specificity for detection of RAS greater than 50% were 89.6% and 91.6%, respectively. In kidneys affected by RAS greater than 50%, captopril administration typically induced a prolongation in parenchymal transit time (324 +/- 90 sec, baseline conditions, v 408 +/- 122 sec, postcaptopril, P less than .01) as against 255 +/- 70 v 251 +/- 64, P = NS, in kidneys supplied by patent arteries or with RAS less than 50%.

Adolescent↗
PubMed1991

Use of technetium-99m-MAG3 for renal scintigraphy after angiotensin-converting enzyme inhibition.

Technetium-99m-mercaptoacetyltriglycine (99mTc-MAG3) was tested in 82 hypertensive patients submitted to renal scintigraphy 1 hr after oral premedication with 50 mg of Captopril. Baseline studies were obtained only for those patients showing abnormal findings in the provocative study. All patients underwent renal arteriography. Sensitivity and specificity for the detection of renal artery stenosis (RAS) greater than 50% were 89% and 91%, respectively. After Captopril administration, tracer parenchymal transit time increased significantly in ischemic kidneys (334 +/- 93 sec in baseline conditions versus 468 +/- 96 sec after Captopril, p less than 0.001) but not in kidneys with no RAS or RAS less than 50% (243 +/- 46 sec versus 271 +/- 95 sec, p = ns). False-positive responses were mostly bilateral and associated with a marked decrease in blood pressure. Technetium-99m-MAG3 is an effective compound for detecting RAS greater than or equal to 50% with Captopril renal scintigraphy. Performing the provocative test as a first step considerably reduced the number of scintigraphic studies required.

Administration, Oral↗
PubMed1991

Dipyridamole technetium-99m-2-methoxy isobutyl isonitrile tomoscintigraphic imaging for identifying diseased coronary vessels: comparison with thallium-201 stress-rest study.

A same-day double injection protocol employing 99mTc-methoxyisobutyl isonitrile (MIBI) and myocardial single-photon emission computed tomography (SPECT) for detecting coronary artery disease (CAD) was assessed in 30 patients. SPECT was performed 1 hr after a first injection (250 MBq) of 99mTc-MIBI, given after 0.56 mg/kg dipyridamole (DPD) infusion. Patients were then reinjected at rest (750 MBq) and were reimaged 1 hr later. Within 1 wk, all patients underwent a complete stress-rest SPECT thallium study. Of the 330 myocardial segments evaluated, 25 were judged ischemic by both techniques, while persistent defects were demonstrated in 50 and in 47 with 99mTc-MIBI and 201TI, respectively. Six regions were considered for diseased vessels identification. Sensitivity and specificity for CAD were 100% and 75%, respectively, for both 201TI and 99mTc-MIBI. Sensitivity for identification of diseased vessels by 201TI was 68% for LAD, 89% for RCA, and 80% for LCX as opposed to 75%, 89% and 80%, respectively, by 99mTc-MIBI. Specificity was 93% in both cases for LAD, 73% and 63% for RCA, and 53% and 46% for LCX.

Adult↗
PubMed1991

[Duplex and Doppler color echocardiography for the study of renovascular hypertension. Comparison with arteriography].

Doppler US was employed to examine 46 patients with suspected renovascular hypertension (RVI) to detect stenosis/occlusion of the renal artery. In 25 cases duplex-Doppler technique was used, in 19 color-Doppler US, and 2 patients were examined with both methods. Doppler US was always performed before angiography which was considered as the reference gold standard. Using duplex-Doppler US, the diagnosis of renal artery stenosis was based on qualitative (spectral analysis of the waveform and absence of flow signal in cases of renal artery occlusion), and semiquantitative parameters (resistive index). Diagnostic accuracy of duplex US--which was compared with that of angiography--was 83%, its sensitivity was 91.6%, and specificity was 85%. With color-Doppler, two additional quantitative parameters were used (peak systolic frequency shift at the stenosis and stenosis index). In this group of patients sensitivity was 70%, specificity was 100%, and accuracy 85%. The good diagnostic yield of the method is counter-balanced by some limitations--e.g., operator dependence and long examination time (30-40 minutes, especially with duplex US). In the authors' opinion, Doppler technique can be used in the diagnosis of RVI, even though further study is necessary to exactly define diagnostic parameters, and to verify reproducibility and both inter- and intra-observer repeatibility. Technological progress may in the future reduce both difficulty and time of the examination.

Adult↗
PubMed1990

[Double injection of Tc99m-methoxy isobutyl isonitrile in the same session: diagnostic accuracy in tomography compared with that of thallium-201 chloride].

Radionuclide imaging with thallium-201 is widely accepted for identifying the presence and the severity of coronary artery disease, but this radiotracer is hampered by some limitations (low-energy photons and long physical half-life) and by delivering difficulties. Therefore, various technetium 99m-labelled compounds have been proposed as myocardial perfusion agents. In particular, technetium 99m methoxy isobutyl isonitrile (Tc99m-MIBI) showed the most favourable characteristics for clinical applications. Recently a study protocol involving a split dose of the radiocompound injected in the same day has been proposed. The aim of this work has been to evaluate the diagnostic accuracy of this procedure coupled with tomographic study (SPECT-MIBI) in a group of patients with documented coronary artery disease and to compare the results with those obtained by means of Tl-201 tomographic studies (SPECT-Tl) in the same patient group. Twenty-four patients, 21 males and 3 females, entered the study: the mean age was 57 +/- 6 years (44-71). For the rest study the patients were given 250 MBq of Tc99m-MIBI. Then, after 2-3 hours, they were reinjected with a second dose of 750 MBq when exercise endpoints were reached. The studies with Tl-201 were carried out the week before or subsequent the Tc99m-MIBI studies. Sensitivity was 88% with SPECT-Tl and 78% with SPECT-MIBI for the anterior descending artery (LAD), 86% and 64% respectively for right coronary artery disease (RCA) and 69% with both procedures for the left circumflex artery (LCX). Specificity was 88% with SPECT-Tl and 78% with SPECT-MIBI LAD, 60% with both procedures for RCA and 55% and 81% respectively for LCX. Coronary artery disease, involving 2 or more vessels, was correctly identified in 93% of patients by Tl-201 studies and only in 60% of patients by Tc99m-MIBI. In several cases the high count rate obtained by Tc99m-MIBI did not allow the identification of hypoperfused segments. In conclusion, a rest-stress double injection of Tc99m-MIBI in a same-day protocol has shown a lower sensitivity for detecting coronary lesions than Tl-201. Moreover, radiation exposure for medical and technical staff is greater with Tc99m-MIBI than with Tl-201.

Adult↗
PubMed1990

Prevention of chronic glomerular uremia in steroid resistant glomerulonephritis. A clinical trial with a new antithrombotic agent.

To investigate the possibility of slowing down disease progression 27 patients with primary glomerular diseases unresponsive to steroids and cytotoxic drugs were treated with Defibrotide. This drug is a single stranded DNA fraction which has profibrinolytic and deaggregating properties and can promote the generation and release of prostacyclin from vascular tissue. Before treatment all patients showed proteinuria in excess of 1 g/day and 16 had a nephrotic syndrome (59%); 10 patients had serum creatinine above 1.6 mg/dl (37%) and 6 were hypertensive. After therapy a significant decrease in daily proteinuria was observed, although the reduction exceeded 50% of pre-treatment values in only 16 patients (59%). A progressive decrease in serum creatinine occurred in patients with abnormal renal function; serial measurement of renal plasma flow showed a progressive improvement with an average increase of 6 and 12%, after 1 and 3 months of treatment, respectively. These observations confirm the view that drugs improving endothelial function and renal hemodynamics can be of value in the treatment of chronic glomerular diseases and can contribute to the maintenance of renal function.

Adult↗