Clinical nuclear medicine
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Clinical nuclear medicine · Dec 1999
Gated Tc-99m sestamibi SPECT versus stress-rest SPECT in detecting coronary artery disease: correlation with coronary angiography in patients without myocardial infarction.
It is possible to simultaneously evaluate wall thickening and perfusion abnormalities with radionuclide techniques that use tracers such as Tc-99m MIBI. We presumed that detection of wall thickening by gated MIBI SPECT imaging in the presence of a stress-induced perfusion defect correlates with reversibility of that defect on resting images. Therefore, the aim of our study was to analyze, in patients without myocardial infarction, resting wall thickening and stress perfusion imaging as an alternative to conventional stress-rest imaging. ⋯ Our data revealed close agreement between reversible perfusion defects on stress-rest MIBI SPECT scans and significant wall thickening on gated MIBI SPECT stress images in patients without previous myocardial infarction (95%). Gated MIBI SPECT stress, without resting studies, which provide an assessment of wall motion and wall thickening, potentially allows stress defect reversibility to be evaluated in patients without previous myocardial infarction.
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Clinical nuclear medicine · Sep 1999
Comparative StudyComparison of the dynamics of bile emptying by quantitative hepatobiliary scintigraphy before and after cholecystectomy in patients with uncomplicated gallstone disease.
Quantitative hepatobiliary scintigraphy, a noninvasive method frequently used to diagnose several biliary tract disorders, shows abnormalities in bile secretion and outflow. It is well known that there are wide variations in the normal pattern of bile emptying, but the effect of cholecystectomy on the bile flow has not yet been investigated. The goal of the current study was to examine the dynamics and normal variations of bile flow by quantitative hepatobiliary scintigraphy before and after cholecystectomy in a group of patients with uncomplicated gallstone disease. ⋯ In patients with their gallbladders in situ, the bile emptying rate showed wide variations and may be moderately slow without distal common bile duct obstruction. After cholecystectomy, the rate of bile emptying accelerated and showed only minor variations, thereby increasing the sensitivity of quantitative hepatobiliary scintigraphy for showing partial biliary obstruction.
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Clinical nuclear medicine · Sep 1999
The use of hepatocyte extraction fraction to evaluate neonatal cholestasis.
Hepatobiliary scintigraphy is used routinely to evaluate infants with neonatal cholestasis. Hepatobiliary scintigraphy determines biliary patency by detecting radioactivity in the bowel on imaging, in duodenal and gastric aspirates, or all of these. During hepatobiliary scintigraphy, the hepatocyte extraction fraction (HEF) is calculated by deconvolution analysis. Normal values of HEF are more than 90%. It is believed that HEF may predict hepatic dysfunction, because, during hepatobiliary scintigraphy, the radiopharmaceutical used in this test is extracted by the hepatocytes from the blood stream. Therefore, a low value of HEF is seen with more severe hepatocellular disease. The goal of this study was to determine whether HEF has any correlation with synthetic liver function, whether HEF can differentiate obstructive from nonobstructive lesions that cause neonatal cholestasis, and whether HEF can predict the outcome of the different causes of neonatal cholestasis. ⋯ A single determination of HEF is of no value in assessing synthetic liver function (as assessed by albumin and prothrombin time), specific diagnoses, and outcomes in patients with neonatal cholestasis. Therefore, a low isolated value of HEF should not be considered suggestive of poor prognosis and outcome in these patients.
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Clinical nuclear medicine · Jun 1999
Case ReportsAutonomic regulation of lymphatic flow in the lower extremity demonstrated on lymphoscintigraphy in patients with reflex sympathetic dystrophy.
Nuclear medicine techniques were used to show that the peripheral lymphatics are under autonomic control in much the same way as the blood vessels that supply the same anatomic region. ⋯ Peripheral lymphatic function is controlled by the autonomic nervous system. In reflex sympathetic dystrophy, peripheral edema may be caused by an increased sympathetic stimulus to the lymphatics. Further study of this phenomenon may show that nuclear medicine studies, such as bone scintigraphy and lymphoscintigraphy, can be used to distinguish patients who will benefit from sympathectomy from those who will not, thereby obviating invasive testing and unnecessary invasive treatment.