Biomedical subjects

M W Hanson

Publications and source records attributed to M W Hanson.

42 records · Page 3Linked to original sources

PubMedDate not supplied

Prediction of severe coronary artery disease by combined rest and exercise radionuclide angiocardiography and tomographic perfusion imaging with technetium 99m-labeled sestamibi: a comparison with clinical and electrocardiographic data.

BACKGROUND: The purpose of this study was to compare the incremental value of clinical information, electrocardiographic data, myocardial perfusion imaging, and radionuclide angiography for predicting severe coronary artery disease at a single testing interval. Clinical information, treadmill exercise studies, radionuclide angiography, and myocardial perfusion imaging are important predictors of severe coronary artery disease. However, the relative and absolute diagnostic importance of each of these methods has not been addressed at a single testing interval. METHODS AND RESULTS: A same-day rest/treadmill exercise perfusion and function study was performed in 167 patients within 90 days of coronary angiography. A multivariable regression model was used to assess the independent informational content of these predictors. Clinical and electrocardiographic data were related strongly to the presence of severe coronary artery disease (chi2 = 12.2 and p < 0.001; chi2 = 11.8 and p < 0.001, respectively). Combined perfusion and functional studies contributed 31% of the diagnostic information beyond that provided by clinical and electrocardiographic data alone (p < 0.05). CONCLUSIONS: These data demonstrate that combined studies of myocardial perfusion and left ventricular function are able to improve prediction of the extent of coronary artery disease, even when clinical and electrocardiographic data are also available.

Cardiac Catheterization↗

PubMedDate not supplied

FDG-PET in the selection of brain lesions for biopsy.

The CT-guided stereotaxic needle biopsy has become a widely used procedure in the diagnostic evaluation of intracranial lesions including tumors. Conventional CT or MR frequently defines the anatomic regions of abnormality, which may be multiple lesions or a single lesion that is heterogeneous in cellular composition owing to the topographic variation of cellular constituency or the combination of active disease, nonspecific inflammation, necrosis, and/or edema. In these cases, selection of the most appropriate site for a successful diagnostic needle biopsy can be difficult. In three patients, we have used [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) to determine the site most likely to provide a diagnostic biopsy result. In the first patient, who presented with confusion, multiple biopsies from the temporal lobe, based on MR abnormalities, revealed only reactive gliosis and edema. Repeat biopsy directed by PET revealed an anaplastic astrocytoma. In a second patient, PET allowed us to differentiate radiation effect from active metastatic breast cancer. In the third patient, who presented with a grand mal seizure, biopsy of a CT-defined hypodense region demonstrated lymphocytosis. Metabolism of FDG was normal or increased in areas of Aspergillus encephalitis at autopsy. These preliminary studies suggest a complementary role for FDG-PET and CT or MR in selected patients for defining the intracranial site most likely to yield a positive biopsy result.

Adenocarcinoma↗

PubMedDate not supplied

FDG-PET in pediatric posterior fossa brain tumors.

Seventeen pediatric patients with posterior fossa brain tumors were studied with 2-[18F]fluoro-2-deoxy-D-glucose (FDG) and positron emission tomography (PET). The FDG uptake was ranked by two observers, and the results were correlated with tumor histology. Increased FDG uptake was associated with more malignant and aggressive tumor types. Heterogeneity of FDG uptake was associated with previous therapy, including radiation therapy and chemotherapy. 2-[18F]Fluoro-2-deoxy-D-glucose PET will likely be an important adjunct in the management of pediatric posterior fossa tumors, much as in adult patients with brain tumors.

Adolescent↗

PubMedDate not supplied

Serial FDG-PET studies in the prediction of survival in patients with primary brain tumors.

OBJECTIVE: This study examines the changes in tumor [18F]fluoro-2-deoxyglucose (FDG) uptake on serial FDG-PET studies and the ability of serial FDG-PET studies to predict survival in patients with treated and untreated primary brain tumors. MATERIALS AND METHODS: The study population included 20 patients with primary brain tumors. Changes in FDG uptake over time were visually assessed and correlated with clinical course and survival. RESULTS: Although little change in FDG uptake was noted for individual patients, high average FDG uptake (greater than or equal to gray matter) on serial studies was associated with shorter survival. Patients with persistently low FDG uptake (less than gray matter) survived significantly longer than patients with persistently high FDG uptake (p = 0.007). CONCLUSION: Serial evaluation of metabolic activity with PET may provide more accurate prognostic information than a single FDG uptake determination in patients with primary brain tumors.

Adult↗

PubMedDate not supplied

Association of physical fitness and transient myocardial ischemia in patients with coronary artery disease.

PURPOSE: To examine the relationship between physical fitness and transient myocardial ischemia (TMI) in the laboratory and during daily life, in a sample of coronary patients with a recent positive exercise test. METHODS: 47 patients with coronary disease (CAD) participated in laboratory mental and exercise stress testing and 48-hour outpatient Holter monitoring after being withdrawn from ant-ischemic medications. During laboratory testing, left ventricular performance was assessed by radionuclide ventriculography. Physical fitness was assessed by measurement of oxygen consumption during symptom-limited exercise treadmill testing. RESULTS: Higher physical fitness subjects were less likely to exhibit wall-motion abnormalities in response to mental stress (P < .05), and to exercise stress (P < .05) testing. They also had smaller decreases in left ventricular ejection fraction (LVEF) in response to mental stress than less fit subjects (P .056), and exhibited a mean increase in LVEF during exercise, compared to the less fit subjects who exhibited a decrease in LVEF (P < .02). Moreover, higher fit subjects exhibited fewer episodes of TMI (P < .04), for a shorter duration (P < .04), and less total ischemic burden (P < .04) during Holter monitoring. CONCLUSION: These findings suggest that within a population of CAD patients, higher levels of physical fitness are associated with less TMI assessed in the laboratory and during routine activities of daily living.

Adult↗

PubMedDate not supplied

[18F]2-fluoro-2-deoxyglucose-positron emission tomography correlation of gadolinium-enhanced MR imaging of central nervous system neoplasia.

PURPOSE: To correlate the findings of gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA)-enhanced MR imaging with positron emission tomography (PET) in the evaluation of central nervous system neoplasia. MATERIALS AND METHODS: Thirty-six lesions identified on noncontrast MR in 35 patients with biopsy-proved intracranial tumors were imaged with both T1-weighted Gd-DTPA MR at 1.5 T and [18F]2-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET). Eighteen women and 17 men with a mean age of 47.1 years (range 22-72) were studied. The degrees of Gd-DTPA enhancement and FDG uptake were rated separately, and then all scans were reviewed together. FDG uptake was graded 1-5. RESULTS: Of the 35 lesions rated, 30 had Gd-DTPA enhancement and 28 of these were hypermetabolic (FDG accumulation greater than white matter) on PET (93% concordance). Twenty-six of 32 neoplastic lesions had Gd-DTPA enhancement. Twenty-four of these enhancing tumors were hypermetabolic. Only one lesion was completely missed on PET but identified on routine spin echo MR. CONCLUSION: Gd-DTPA MR and FDG-PET are complementary and there is a high concordance of Gd-DTPA-enhancing tumours displaying FDG hypermetabolism. Although FDG hypermetabolism and Gd-DTPA enhancement are usually suggestive of high-grade malignancy, anaplastic astrocytomas may not enhance with Gd-DTPA and can be hypometabolic. In addition, benign intracranial tumors (two cases of meningioma) and radiation necrosis can be associated with both FDG uptake and Gd-DTPA enhancement.

Adult↗