technetium-tc-99m-exametazime and Cardiovascular-Diseases

In the past 7 years, single photon emission computed tomography (SPECT) has evolved from an interesting nuclear medicine technique rarely performed because of technical difficulties into a valuable clinical tool in the management of cancer cases. The development of stable multidetector instruments with collimators and gantries specifically designed for SPECT and the introduction of new radiopharmaceuticals recently approved by the U.S. Food and Drug Administration have rapidly moved SPECT from the field of clinical investigation to clinical practice. SPECT is a valuable addition to other tomographic modalities capable of displaying the physiology of disease as well as anatomy. In this work the authors describe the role of SPECT in a cancer center and, in particular, how they use it to solve clinical problems. They also review the published literature, when appropriate. The authors have found SPECT of particular value in evaluation of myocardial ischemia, in differentiating tumor recurrence from posttherapy changes in the lymphomas, in tumor diagnosis and surveillance, and in separating hemangioma from malignant lesions in the liver.

Topics: Abdomen; Amphetamines; Antibodies, Monoclonal; Bone Diseases; Brain Diseases; Cardiovascular Diseases; Humans; Neoplasms; Organotechnetium Compounds; Oximes; Quality Control; Technetium Tc 99m Exametazime; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon

Individual responses of cerebral blood flow to acetazolamide are highly variable. We hypothesized that this may be due to interactions with cardiovascular diseases and medication. Therefore, we measured the haemodynamic effects of acetazolamide in patients with various cardiovascular disorders and evaluated whether these had any correlation with calculated cerebral perfusion reserve. Ten male patients aged 58 +/- 9 years (mean +/- S.D.) were studied with first-pass radionuclide ventriculography and echocardiography before and 20 min after the administration of 1 g acetazolamide. Systolic blood pressure fell from 133 +/- 21 to 128 +/- 19 mmHg (P < 0.05) and the cardiac output to total blood volume ratio increased from 0.85 +/- 0.18 to 0.92 +/- 0.11 (P = 0.05), indicating a 14% reduction in peripheral vascular resistance. In a further study, 15 patients aged 60 +/- 7 years (22 studies) were studied simultaneously with a nuclear stethoscope and 99Tc(m)-hexamethylpropyleneamine oxime single photon emission tomography before and after acetazolamide administration. The cardiac output ratio increased from 0.81 +/- 0.17 to 0.89 +/- 0.17 (P < 0.05) and showed a significant inverse correlation with calculated cerebral perfusion reserve. In conclusion, acetazolamide increases the cardiac output ratio and reduces systolic blood pressure, indicating reduced peripheral vascular resistance in patients with various cardiovascular diseases and medication. The increase in the cardiac output ratio is inversely related with calculated cerebral perfusion reserve. This helps to explain the high individual variability in calculated cerebral perfusion reserve.

Topics: Acetazolamide; Adult; Aged; Blood Pressure; Carbonic Anhydrase Inhibitors; Cardiac Output; Cardiovascular Diseases; Cerebrovascular Circulation; Echocardiography; Female; Hemodynamics; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Radionuclide Ventriculography; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Vascular Resistance