Positron emission tomography (PET) is an established imaging tool in oncology that has also been used in infectious and inflammatory diseases. PET combined with computed tomography (PET/CT) can be used to visualize metabolic activity with precise localization. We report an infant with late presentation of poststernotomy mediastinitis, the diagnosis and localization of which was confirmed by PET/CT. An 8-month old infant, who had undergone the Jatene procedure and right ventricle outflow reconstruction 6 months prior, was admitted for inflammation surrounding the superior aspect of the healed scar. Cultures from the wound grew methicillin-resistant Staphylococcus aureus (MRSA). Although the only symptom was discharge from the wound, and there were no other signs or symptoms suggestive of severe general infection, substernal abscess was suspected by magnetic resonance imaging. Since PET/CT revealed high accumulation of 18-fluorodeoxyglucose at the substernal region, the diagnosis of MRSA mediastinitis was made, which was confirmed by subsequent surgical treatment.

OBJECTIVE: Agonists of alpha7-nicotinic acetylcholine receptors (nAChRs) have been developed as potential therapeutic drugs for neuropsychiatric diseases such as schizophrenia and Alzheimer's disease. Positron emission tomography (PET) is a noninvasive brain imaging technique to measure receptor occupancy in the living human brain. Although much effort has been expended to create specific PET radioligands for alpha7-nAChRs in the brain, only 4-[11C]methylphenyl-1,4-diazabicyclo[3.2.2.]nonane-4-carboxylate ([11C]CHIBA-1001) is currently available for clinical studies. In contrast, two 5-hydroxytryptamine-3 (5-HT3) receptor antagonists, tropisetron and ondansetron, have been used to treat patients with chemotherapy-induced or postoperative nausea and vomiting. Furthermore, tropisetron, but not ondansetron, possesses high affinity for alpha7-nAChRs. In the present study, we evaluated the receptor occupancy in the human brain after a single oral administration of tropisetron and ondansetron using [11C]CHIBA-1001 and PET. METHODS: Two serial dynamic PET scans using [11C]CHIBA-1001 in healthy non-smoking male subjects were performed before and after receiving an oral administration of these medications. RESULTS: A single oral administration of tropisetron, but not ondansetron, decreased the total distribution volume of [11C]CHIBA-1001 in the human brain. CONCLUSION: This study shows that tropisetron, but not ondansetron, could bind to alpha7-nAChRs in the human brain after a single oral administration. Therefore, [11C]CHIBA-1001 may be a useful PET radioligand to measure the occupancy of alpha7-nAChRs in the human brain.
Administration, Oral ; Alzheimer Disease ; Brain ; Electrons ; Humans ; Indoles ; Male ; Neuroimaging ; Ondansetron ; Positron-Emission Tomography ; Postoperative Nausea and Vomiting ; Receptors, Cholinergic ; Receptors, Nicotinic ; Schizophrenia