Search

Abstract. The diagnostic potential of technetium-99m hexamethylpropylene amine oxime (HMPAO) following systemic administration of the cerebral vasodilator acetazolamide (acetazolamide test) was evaluated by regional cerebral blood flow (rCBF) single-photon emission tomography (SPET) in patients with Alzheimer's disease (AD) or vascular dementia (VD). An initial, high-resolution SPET study was performed with [sup 99m]Tc-HMPAO, and after 2 days the patients were re-evaluated with [sup 99m]Tc-HMPAO following systemic administration of acetazolamide. Reconstructed SPET slices were evaluated visually and semiquantitatively by a semi-automatic rCBF map method. When [sup 99m]Tc-HMPAO alone was used, bilateral hypoperfusion was found in the temporal and/or parietal regions in 33% (6/18) of the VD patients and in 70% (23/33) of the AD patients. The corresponding data obtained by quantitative evaluation were 41% (7/17) and 71% (15/21), respectively. The vascular reserve capacity, as determined with the acetazolamide test, was preserved visually in 22% (4/18) and quantitatively in 29% (5/17) of the VD patients, but in 73% (24/33) and 76% (16/21) of the AD patients. The differences in the perfusion patterns between the VD and AD patients were statistically significant (P<0.01, Fischer's exact test). Of the VD patients with hypoperfusion (bilateral temporal... [ABSTRACT FROM AUTHOR]

In systemic lupus erythematosus (SLE), brain and kidney are the most frequently affected organs. Measurements of cerebral blood flow and metabolism by means of positron emission tomography (PET) and single-photon emission tomography (SPET) can contribute to the diagnostic assessment of the involvement of the central nervous system (CNS) in SLE. Functional imaging has been proven to be more sensitive than morphological imaging (magnetic resonance imaging and computed tomography). In this report, we present the case of a 70-year-old female patient, suffering from SLE without symptoms of CNS involvement. In addition to a SPET study using technetium-99m hexamethylpropylene amine oxime (Tc-HMPAO) and a PET scan with fluorine-18 deoxyglucose (FDG), a SPET study after acetazolamide injection was performed in order to assess the cerebral perfusion reserve. While the PET scan showed no major abnormalities, and the baseline SPET study revealed only minor changes, the acetazolamide-enhanced SPET study revealed a marked reduction of the cortical perfusion reserve, particularly in both frontal lobes. It is concluded that 'preclinical' CNS involvement, mainly caused by pathological mechanisms involving the cerebral blood vessels, can be considered to exist in this patient with SLE. [ABSTRACT FROM AUTHOR]

A total of 29 patients with coronary artery disease (CAD) were investigated with 15-(p-[I] iodophenyl)pentadecanoic acid (I-IPPA) and sequential single photon emission tomography (SPET). Of these, 19 were studied after aorto-coronary bypass graft surgery. Some 13 patients without evidence of CAD served as a control group. Two SPET studies (early and late) were carried out within 45 min after intravenous administration of 200 MBq I-IPPA at peak sub-maximal exercise. Semi-quantification of uptake (related to perfusion) and turnover (linked to metabolism) was obtained by segmental comparison of oblique slices. Taking coronary arteriography as the 'gold standard', I-IPPA scintigraphy had the following figures of merit for sensitivity and specificity in the diagnosis of CAD: for the left anterior descending artery territory 93% and 95%, for the left circumflex artery region 96% and 92%, and for the right coronary artery territory 77% and 92%, respectively. In all, 90% of the reperfused myocardial segments showed an improvement of uptake. Of these, 61% exhibited increased turnover after revascularization and 39% had pathologic turnover and thus a dissociation of improvement of perfusion and oxidative metabolism after surgery. [ABSTRACT FROM AUTHOR]

To examine the capacity of detecting regional cerebral blood flow (rCBF) disturbances in stroke, measurements with Xe inhalation and I-amphetamine (IMP) SPECT were performed within 1-2 days in 19 patients. IMP SPECT images in transverse sections consisting of outer and inner areas were correlated with 32 regions of Xe rCBF. Xe rCBF was assessed by ISI, CBF, and F. Inter hemispheric ratio correlation showed outer IMP uptake correlated better with Xe CBF indices than the inner one. With higher ratios of Xe rCBF, IMP uptake ratios were variable, suggesting less usefulness of this parameter in evaluation of mild ischemia. Values of IMP in outer regional hypo and hyperemic areas correlated better with those of Xe rCBF than the inner ones. In regional ratios of hypo and hyperemic areas from hemispheric mean, outer IMP uptake correlated with Xe CBF indices, reflecting regional disturbances of fast clearing tissue perfusion. Regression lines between ratios in Xe CBF and IMP uptake were located below one to one correlation, and dissociated more for hyperemic regions. IMP SPECT correlated better with Xe rCBF for tissues with reduced perfusion but underestimated hyperemic regions as measured with the Xe method. The data suggest outer cerebral IMP uptake evaluated by SPECT could reflect flow disturbances in the brain cortex. [ABSTRACT FROM AUTHOR]

Pays tribute to doctor Giorgio Ferlin who died on December 11, 2000. Career in the field of nuclear medicine; Work experiences; Academic background.