Sixty-three hypertensive patients with probability of obstructive renal artery disease underwent both Captopril renal scintigraphy (CRS) and echo-Doppler flowmetry (EDF) before undergoing renal angiography. Angiography revealed renal artery stenosis (RAS) in 42 patients (unilaterally in 26 and bilaterally in 16). The sensitivity and specificity in the identification of RAS > or = 50% were 90% and 94%, respectively for Captopril renography, and 85% and 78% for echo-Doppler flowmetry. Captopril renography correctly identified stenoses greater than 50%, which is usually held to be the limit of hemodynamic significance. While the Doppler examination was more sensitive than Captopril renography (sensitivity 79% versus 64%) in the detection of all degrees of RAS, less information on the functional significance of RAS was provided. Both CRS and EDF could be usefully employed to assess kidney perfusion, but their appropriate clinical use must take into account inherent differences between the two techniques.

Adolescent↗

PubMedDate not supplied

Cerebral SPECT with 99mTc-HMPAO in extracranial carotid pathology: evaluation of changes in the ischemic area after carotid endarterectomy.

The authors report their experience in studying patients undergoing carotid endarterectomy with simple photon emission computed tomography (SPECT). This technique made it possible to identify areas of preoperative cerebral hypoperfusion in 54.8% of the patients which had a good correlation with neurological symptoms. To distinguish gradual changes in the ischemic lesions, a method of assessing the surface of the hypoperfused areas was adopted. In addition, SPECT made it possible to detect a greater number of hypoperfused areas even in sites other than those revealed by CT. Moreover, there was good correlations between the SPECT data and the grade and site of the carotid lesion and the data provided by some intraoperative monitoring procedures. The Authors therefore propose the use of SPECT in the evaluation of patients with cerebrovascular insufficiency following a carotid disease.

Adult↗

PubMedDate not supplied

Clinical evaluation of four study protocols with 99mTc-methoxyisobutylisonitrile and SPECT for detecting diseased coronary vessels.

Different techniques have been suggested for coronary artery disease (CAD) detection with single-photon emission computed tomography (SPECT) and 99mTc-methoxyisobutylisonitrile (99mTc-MIBI). We evaluated four protocols employing myocardial SPECT with 99mTc-MIBI in separate groups of patients. The first involved stress and rest studies performed on separate days, whereas the other three involved "same day" studies. Group 1 (n = 23) was examined in separate sessions, after ergometric exercise and at rest. Group 2 (n = 24) was first injected after dipyridamole infusion, then injected again at rest after completion of the stress study. Group 3 (n = 24) was first injected at rest and imaged one hour later. Afterwards an ergometric stress was performed, with injection at peak exercise. The inverse sequence was adopted for group 4 (n = 24). All patients underwent coronary angiography. For all groups and vessels, the sensitivity and specificity for diseased coronary artery identification were not statistically different. Studies using the new myocardial perfusion tracer 99mTc-MIBI may therefore be completed on the same day or on separate days according to laboratory and patient needs. Dipyridamole iv infusion proved to be as effective as ergometric exercise for diseased coronary artery identification.

Clinical Protocols↗

PubMedDate not supplied

Regional left ventricular ejection fraction with single crystal gammacamera and gated equilibrium technique: repeatability and inter-observer variability.

Regional left ventricular ejection fraction calculated by means of gated blood pool scintigraphy was compared with that obtained from contrast ventriculography in a group of 20 patients, submitted to both procedures within a month. To evaluate repeatability both at rest and during stress, a second scintigraphic study was carried out after three weeks, with no change in drug regimen. Inter-observer variability was assessed in a randomly selected subgroup of 16 patients, in whom a computation was repeated by a second operator. Comparison of scintigraphic results showed a satisfactory agreement, and measurement agreement for global left ventricular ejection fraction was very good. As regards interobserver variability, each of the three myocardial segments examined (septal, lateral and infero-apical) showed good agreement. As regards repeatability, global left ventricular ejection fraction, proved readily reproducible both for rest and stress studies, with relatively small differences in observed values. Regional ejection fraction, on the other hand, had a high variability, especially during stress. It is suggested that for regional ejection fraction evaluation, reproducibility studies should be performed in order to better correlate result changes to clinical outcome after medical or surgical therapy.

Aged↗

PubMedDate not supplied

Diagnostic accuracy of single photon emission computed tomography with thallium-201 for the identification of diseased coronary arteries. Comparison between dipyridamole infusion and exercise stress test.

Myocardial perfusion imaging with 201Tl and single-photon emission computed tomography (SPECT) was carried out in two groups of patients, subsequently submitted to diagnostic coronary angiography. SPECT was performed in group 1 (41 patients) after slow i.v. infusion of dipyridamole and in group 2 (162 patients) after tracer injection at maximal ergometric exercise. To evaluate the diagnostic capability of SPECT in the detection of diseased coronary vessels, the left ventricular myocardium was subdivided into 6 segments related to the three major coronary arteries. Sensitivity for the left anterior descending artery was 77% in group 1 and 79% in group 2; specificity was 80% and 96%, respectively. Sensitivity for the right coronary artery was 91% in group 1 and 85% in group 2; specificity was 81% and 73%. For the left circumflex artery sensitivity was 65% for group 1 and 67% for group 2, while specificity was 89% and 88%, respectively. Myocardial SPECT results after ergometric exercise and dipyridamole infusion turned out to be almost superimposable. Dipyridamole stress might be considered appropriate as a provocative test when physical exercise cannot be carried out.

Adult↗

PubMedDate not supplied

Carotid endarterectomy. Pre- and post-operative monitoring with cerebral SPECT.

In the pre-operative evaluation of carotid endarterectomy, the knowledge of ischemic areas may be helpful to reduce the operative risk. A positive CT scan is often correlated with an increased operative risk. The single photon emission computed tomography (SPECT) allows us to visualize ischemic areas not shown by the CT; these areas are almost always correlated to neurological symptomatology. In patients with positive CT scan, the ischemic areas shown by SPECT are generally larger, because this technique visualize the ischemic area surrounding the cerebral infarct (penumbra). After carotid EA, SPECT is useful to show the hemodynamic modifications induced by this operation. In a series of 15 patients we observed an improvement of the cerebral blood perfusion characterized by the normalization of the blood flow in 7/12 (58%) of the ischemic areas observed pre-operatively), an improvement in 3/12 and a normalization or an improvement in the contralateral hemisphere in 5/7 of the areas. In conclusion SPECT is a useful technique to study the cerebral pathophysiology of both cerebrovascular disease and its surgical treatment.

Aged↗

PubMedDate not supplied