[Show abstract][Hide abstract] ABSTRACT: Our aim was to evaluate the use of PET with (11)C-metomidate and (18)F-FDG for the diagnosis of adrenal incidentalomas.
Twenty-one patients underwent hormonal screening before dynamic imaging of the upper abdomen with (11)C-metomidate, and for 19 of these 21 patients, static (18)F-FDG imaging followed. Uptake of (11)C-metomidate and (18)F-FDG in incidentalomas was quantified and correlated with the hormonal work-up and the mass size on CT (median, 2.5 cm; range, 2-10 cm).
The final diagnoses were hormonally active adenoma (n = 7), nonsecretory adenoma (n = 5), adrenocortical carcinoma (n = 1), pheochromocytoma (n = 2), benign noncortical tumor (n = 2), normal adrenal (n = 1), and malignant noncortical tumor (n = 3). Diagnosis was established at surgery (n = 9), percutaneous biopsy (n = 4), or follow-up (n = 8). The highest uptake of (11)C-metomidate, expressed as standardized uptake value (SUV), was found in adrenocortical carcinoma (SUV = 28.0), followed by active adenomas (median SUV = 12.7), nonsecretory adenomas (median SUV = 12.2), and noncortical tumors (median SUV = 5.7). Patients with adenomas had significantly higher tumor-to-normal-adrenal (11)C-metomidate SUV ratios than did patients with noncortical tumors. (18)F-FDG detected 2 of 3 noncortical malignancies but failed to detect adrenal metastases from renal cell carcinoma. All inactive and most active adenomas were difficult to detect with (18)F-FDG against background activity, whereas both pheochromocytomas and adrenocortical carcinoma showed slightly increased uptake of (18)F-FDG. There was no correlation between uptake of (11)C-metomidate or (18)F-FDG and mass size.
(11)C-Metomidate is a promising PET tracer to identify incidentalomas of adrenocortical origin. (18)F-FDG should be reserved for patients with a moderate to high likelihood of neoplastic disease.
Full-text · Article · Jul 2004 · Journal of Nuclear Medicine
[Show abstract][Hide abstract] ABSTRACT: Chlamydia pneumoniae infection has been associated with atherosclerosis by sero-epidemiological, histopathological and interventional studies, and animal experiments. We hypothesized that if chlamydial infection is causative of atherosclerosis, the occurrence of antibodies against C. pneumoniae should be associated with coronary vasomotor dysfunction - an early sign of atherosclerosis.
To study the association between C. pneumoniae infection and coronary vasomotor function in young men without signs of ischemic heart disease.
Serum IgG and IgA antibody concentrations against C. pneumoniae were determined in 125 clinically healthy subjects undergoing positron emission tomography (PET) studies. Myocardial blood flow was measured at rest and during pharmacologically induced hyperemia using [15O]H2O Coronary flow reserve was calculated as the ratio of hyperemic blood flow to resting blood flow.
No association was found between serum C. pneumoniae antibody concentrations and myocardial blood flow parameters. In contrast, more conventional risk factors for coronary artery disease, such as total cholesterol and apolipoprotein B, were inversely associated with hyperemic flow and flow reserve.
We found no association between C. pneumoniae antibodies and coronary vasomotor function in subjects without ischemic heart disease. Thus, these results do not support the role of C. pneumoniae infection as an early phase risk factor for coronary artery disease.
No preview · Article · Feb 2002 · Annals of Medicine