Patrizia Magnani

Incidental finding of parathyroid adenoma with 11C-choline PET/CT.

Positron emission tomography/computed tomography (PET/CT) with 11C-choline is an established diagnostic tool for restaging prostate cancer patients with biochemical failure after primary treatment. In the present case, 11C-choline PET/CT was performed in a prostate cancer patient with skeletal metastases, treated with hormonal therapy. In addition to the detection of pathologic uptake at prostate and vertebra, 11C-choline uptake occurred in the neck. The finding was suggestive for a parathyroid adenoma on subsequent ultrasound, then finally confirmed by parathyroid scintigraphy and histopathological analysis performed after hemithyroidectomy.

In vivo imaging of chromogranin A-positive endocrine tumours by three-step monoclonal antibody targeting.

The detection of chromogranins (Cg) by immunohistochemistry and serology represents a new in vitro diagnostic tool for endocrine tumours. We have recently reported on the feasibility of targeting chromogranin A (CgA) for in vivo detection of pituitary adenomas by immunoscintigraphy (ISG). The scintigraphic procedure, based on an anti-CgA monoclonal antibody and on the avidin-biotin three-step method (Cg-3S-ISG), was evaluated on a group of 29 consecutive patients with known or suspected endocrine tumours other than pituitary adenomas, i.e. medullary thyroid carcinoma, carcinoid, insulinoma and parathormone- or ACTH-producing tumours. Primary tumours (10) and recurrences (16) were visualised in 26 patients, whereas conventional imaging techniques (planar radiography, computerised tomography, magnetic resonance imaging and ultrasonography) failed to detect the tumour sites in ten of the same (Cg-3S-ISG-positive) patients. Therefore, these preliminary results indicate that Cg-3S-ISG, the first immunological method able to detect endocrine tumours in vivo, has a higher diagnostic accuracy than conventional imaging techniques (93.1% compared with 65.5%).

In vivo evaluation of timing, degree, and distribution of bacterial translocation following experimental small bowel transplantation

These studies were designed to evaluate the correlation between morphologic and functional changes after heterotopic auxiliary small bowel isograft with systemic venous drainage and two ostomies in 20 Lewis rats. Morphologic damage of the graft was scored by full-thickness biopsies before surgery and 1, 3, 5, and 7 days after transplant. Functional evaluation of the graft was done, at the same time points, by urinary excretion of lactulose and mannitol injected in the proximal ostomy. The intestinal permeability was also studied by injecting Escherichia coli labeled with indium-111 oxine in the proximal ostomy. Translocation of radiolabeled bacteria was quantitated in extraintestinal tissues by radionuclide counts and number of viable organisms and in vivo by scinti-graphic imaging. One day after transplant, significant graft damage (score 17.2±4.2) was observed when compared with the pretransplant value (7.3±2.6). The degree of tissue injury was similar on days 3 (15.8±3.5) and 5 (16.1 ±3.9) after transplant and remained high on day 7 (11.8±2.8). The lactulose to mannitol ratio showed a significantly increased permeability on day 1 (17.5) versus pretransplant values (2.6), remained high on day 3 (8.6), and returned to normal values on day 5 (2.8). Translocation of bacteria to distant organs, as measured by both radionuclide counts and number of viable organisms, was strikingly enhanced on day 1 after transplantation, compared with control animals, but returned to the pretransplant value on day 3. A good qualitative and quantitative correlation was observed between radionuclide counts in the extraintestinal organs and in vivo images obtained by scintigraphic scanning. In conclusion, in this model, timing and degree of bacterial translocation do not seem to correlate well, with the exception of the acute posttransplantation phase, with morphologic and perme ability changes of the graft. Evaluation of translocation by scintigraphic imaging appears a suitable approach to study in vivo the kinetics and distribution of this process.