High and typical 18F-FDG bowel uptake in patients treated with metformin.

PURPOSE: This prospective and bi-centric study was conducted in order to determine the impact of antidiabetic treatments (AD) on (18)F-FDG bowel uptake in type 2 diabetic patients. METHODS: Fifty-five patients with previously diagnosed and treated type 2 diabetes mellitus (group 1) were divided in two subgroups: AD treatment including metformin (n=32; group 1a) and AD treatment excluding metformin (n=23; group 1b). The 95 patients without diabetes mellitus made up controls (group 2). (18)F-FDG uptake in small intestine and colon was visually graded and semi-quantitatively measured using the maximum standardized uptake value. RESULTS: (18)F-FDG bowel uptake was significantly increased in AD patients (group 1) as compared to controls (group 2) (p<0.001). Bowel uptake was significantly higher in AD patients including metformin (group 1a) as compared to AD patients excluding metformin (group 1b) (p<0.01), whose bowel uptake was not significantly different from controls (group 2). A metformin treatment was predictive of an increased bowel uptake in the small intestine (odds ratio OR=16.9, p<0.0001) and in the colon (OR=95.3, p<0.0001), independently of the other factors considered in the multivariate analysis. Bowel uptake pattern in the patients treated with metformin was typically intense, diffuse and continuous along the bowel, strongly predominant in the colon, in both the digestive wall and lumen. CONCLUSION: This study emphasizes that metformin significantly increases (18)F-FDG uptake in colon and, to a lesser extent, in small intestine. It raises the question of stopping metformin treatment before an (18)F-FDG PET/CT scan is performed for intra-abdominal neoplasic lesion assessment.

[Positron emission tomography in internal medicine]. / Tomographie par émission de positons en médecine interne.

FDG-PET is now an established diagnostic tool in oncology. Fluorodeoxyglucose is not a specific tracer for malignant lesions but rather for elevated glucose metabolism, present not only in cancer but also in inflammatory and infectious lesions. FDG-PET has thus been suggested for diagnosis of fevers of unknown origin, deep bone or visceral infectious foci, inflammatory vasculitis or sarcoidosis and unknown primary tumors, all frequent situation in internal medicine. The main characteristics of FDG-PET are its ability to rule out focal inflammation or infection with a high degree of certainty when the examination is negative because of its good negative predictive value and its usefulness as an early marker of therapeutic response, compared with anatomy-based or conventional scintigraphic imaging. Large-scale prospective studies are necessary, however, before FDG-PET is integrated into routine clinical use. It should be compared with different techniques already validated (biology, radiology, conventional scintigraphic imaging) and its cost-effectiveness should be evaluated.

Pulmonary cement embolism after percutaneous vertebroplasty: a rare and nonthrombotic cause of pulmonary embolism.

Percutaneous vertebroplasty consists of injection of acrylic cement - polymethylmethacrylate - into a vertebral body to obtain pain relief and increase its mechanical stability. The procedure is indicated for painful hemangiomas and for painful vertebral compression fractures due to osteoporosis or malignancy. Although vertebroplasty is an efficient treatment, it is not free of complications. We present the case of a patient with pulmonary cement embolism after percutaneous vertebroplasty. Because such patients may be completely asymptomatic, but may also present with acute and severe, cardiovascular instability, clinicians and nuclear physicians should be aware that pulmonary embolism of polymethylmethacrylate may occur after percutaneous vertebroplasty.

Presymptomatic diagnosis of experimental Parkinsonism with 123I-PE2I SPECT.

Presymptomatic diagnosis of the loss of nigrostriatal neurons that characterises Parkinson's disease, is a crucial issue for future neuroprotective therapies as degeneration exceeds 70 to 80% when symptoms appear. Here we propose an early diagnosis method that utilises single photon emission computerized tomography (SPECT) coupled to the iodine-123-labelled selective dopamine transporter ligand N-(3-ioprop-2E-enyl)-2-beta-(4-methylphenyl)nortropane ((123)I-PE2I), applying Logan's graphical method for quantification. Sequential (123)I-PE2I SPECT acquisitions were performed in nonhuman primates chronically treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine according to a regimen that consistently produces a progressive Parkinsonian state. While classical neurological examination only allows detection of Parkinsonian signs at Day 12 of the protocol of intoxication, the mean distribution volume ratio calculated according to Logan's graphical method is significantly decreased from Day 6 onward, i.e., when animals are clinically normal. (123)I-PE2I SPECT is a very sensitive method to detect presymptomatic lesions of nigrostriatal neurons and the first to be experimentally validated. It could now be used clinically for early diagnosis and follow-up of neuroprotective treatment.