Journal of nuclear medicine : official publication, Society of Nuclear Medicine
-
Pilot studies have shown good sensitivity and specificity for (18)F-FDG PET in detecting gastrointestinal lesions of Crohn's disease. The combination of (18)F-FDG PET with CT may further improve the localization and characterization of lesions with increased (18)F-FDG uptake. Our aim was to assess the use of (18)F-FDG PET/CT in evaluating the activity and location of Crohn's disease along the gastrointestinal tract. ⋯ (18)F-FDG PET/CT was globally well correlated to the clinical, endoscopic, and biologic activity of Crohn's disease. Above all, this technique had a good sensitivity for the detection of intestinal and colonic segments with moderate to severe mucosal lesions. The potential impact of this promising tool on the global management of patients with Crohn's disease should be further evaluated in prospective studies.
-
Revascularization of viable myocardial segments has been shown to improve left ventricular (LV) function and long-term prognosis; however, the surgical risk is comparatively higher in patients with a low ejection fraction (EF). We compared contrast-enhanced MRI with (18)F-FDG PET/(201)Tl SPECT for myocardial viability and prediction of early functional outcome in patients with chronic coronary artery disease (CAD). ⋯ Accurate prediction of early functional outcome by PET/SPECT and contrast-enhanced MRI is possible.
-
Degeneration of dopaminergic neurons of the substantia nigra pars compacta is a cardinal feature of Parkinson's disease (PD). Although uncertain, the pathology has been suggested to derive from a malfunction of the complex interaction between dopaminergic and metabotropic glutamate receptors (mGluRs). To further address this issue, we investigated the imaging profile and expression of dopamine D(2) receptors and mGluRs in a classic parkinsonian rodent model induced by the toxin 6-hydroxydopamine. ⋯ These findings support the existence of compensatory mechanisms in nigrostriatal dopamine degeneration and provide new insights that help further dissect some of the pathways underlying neurodegeneration. In addition, these results reconfirm that PET is a valuable tool for multilevel receptor studies, significantly contributing to the understanding of pathogenic mechanisms and ultimately opening new avenues in the study of neuroprotective approaches toward PD.
-
Several radiopharmaceuticals such as (18)F-FDG, (123)I-metaiodobenzylguanidine (MIBG), and (99m)Tc-tetrofosmin have demonstrated uptake in brown adipose tissue (BAT). It is important to recognize these normal variants so that they are not misinterpreted as a significant pathologic state. In addition, these radiopharmaceuticals may shed light on BAT physiology. (18)F-6-fluorodopamine (F-DA) is being used as a PET radiopharmaceutical to image adrenergic innervation and suspected pheochromocytoma. Past reports have suggested that BAT is increased in pheochromocytoma patients. ⋯ (18)F-F-DA can image BAT, most likely by localizing to sympathetic innervations in a manner similar to (123)I-MIBG. Patients with pheochromocytoma may have a greater BAT tissue mass or activation because of elevated levels of circulating catecholamines. Quantitative PET with (18)F-FDG and (18)F-F-DA may have a role in in vivo studies of BAT physiology in humans or animal models.
-
The response of cancer to chemotherapy can be quantified using (18)F-FDG to indicate changes in tumor metabolism. Quantification using the standardized uptake value (SUV) is more feasible for clinical practice than is the metabolic rate of (18)F-FDG (MRFDG), which requires longer, dynamic scanning. The relationship between MRFDG and SUV depends in part on how each accounts for blood clearance of tracer. We tested whether chemotherapy and treatment with granulocyte colony-stimulating factor (CSF) changed the blood clearance curves and therefore affected the relationship between MRFDG and SUV. ⋯ Chemotherapy and granulocyte CSF treatment resulted in a lower (18)F-FDG blood AUC. The maximum detectable percentage change in (18)F-FDG uptake is less when quantifying via static SUV than via dynamic MRFDG. This effect is small in most patients but may have clinical significance for measuring the response of patients with a low pretherapy (18)F-FDG uptake.