Biomedical subjects

Nassima Younsi

Publications and source records attributed to Nassima Younsi.

4 recordsLinked to original sources

PubMed2006

[PET in thyroid cancers].

FDG PET can detect thyroid cancer in patients referred for exploration of a different cancer. Because of its lack of specificity, however, this modality is not indicated for examination of thyroid nodules: ultrasonography and fine needle biopsy with cytology allow histological diagnosis, which can be completed by iodine-123 scintigraphy when an autonomous nodule is suspected. No information is currently available about the utility of FDG PET in preoperative staging. In follow-up of patients undergoing thyroidectomy for adenocarcinoma, FDG PET is useful for detecting recurrence in cases where serum thyroglobulin levels rise and iodine-131 scintigraphy is negative: surgical resection may be appropriate. Nonetheless FDG PET should be performed more widely and earlier: the initial presence of foci positive for FDG is a major predictor of shorter survival, and most cancer lesions take up either iodine or FDG. In follow-up of medullary carcinoma, FDG PET detects residual tissue better than any other scintigraphic procedures, especially when serum levels of CEA (carcinoembryonic antigen) are rising rapidly. FDOPA PET seems to have better sensitivity than FDG-PET and may be useful in occult recurrence, as three case reports indicate.

Adenocarcinoma↗

PubMed2005

Usefulness of combination of high-resolution ultrasonography and dual-phase dual-isotope iodine 123/technetium Tc 99m sestamibi scintigraphy for the preoperative localization of hyperplastic parathyroid glands in renal hyperparathyroidism.

BACKGROUND: The usefulness of both dual-phase dual-isotope iodine 123 ( 123 I)/technetium Tc 99m ( 99m Tc) sestamibi scintigraphy and ultrasonography for the detection of hyperplastic parathyroid glands secondary to renal hyperparathyroidism is rarely addressed; most studies focus on primary hyperparathyroidism. However, it may be crucial to identify and accurately localize hyperplastic glands before surgery. METHODS: To study the usefulness of high-resolution ultrasonography (performed by both the radiologist and surgeon) and dual-phase dual-isotope 123 I/ 99m Tc sestamibi scintigraphy in patients with renal hyperparathyroidism, a series of 20 patients consecutively referred for parathyroidectomy was studied prospectively. Results of both examinations, independently scored, were correlated with surgical and histopathologic findings for each hyperplastic parathyroid gland localization. RESULTS: All parathyroid glands except 1 were found during primary surgery consisting of a subtotal parathyroidectomy (success rate, 99%). The missed gland was removed successfully 1 month later. Neither supernumerary nor ectopic glands were found. Mean weight of totally removed parathyroid glands was 633 mg. Ultrasonography detected 75% of hyperplastic parathyroid glands; dual-phase 123 I/ 99m Tc sestamibi scintigraphy, 66%; and a combination of both, 88%. Most missed glands at scintigraphy corresponded to superior glands, whereas false-negative results at ultrasonography correlated with low gland weight. CONCLUSION: Combined ultrasonography and 123 I/ 99m Tc sestamibi scintigraphy should be considered for routine use to localize hyperplastic parathyroid glands in patients with renal hyperparathyroidism undergoing surgery. We suggest performing scintigraphy first, before ultrasonography, to guide the radiologist to areas of hyperfunctioning glands. In our experience, this proved very helpful in achieving a high surgical success rate in patients with renal hyperparathyroidism, especially when the surgeon visualizes the parathyroid glands at ultrasonography.

Adult↗

PubMed2004

Detection of recurrent colorectal carcinoma by 18F-FDG: comparison of the clinical performances of FDG PET and FDG CDET.

OBJECTIVES: To assess the clinical performance of fluorodeoxyglucose positron emission tomography (FDG PET) using either a coincidence (CDET) gamma camera or PET equipment with Nal crystals for the detection of recurrences of colorectal cancer. METHODS: From July 1997 to December 1999, 290 examinations were performed in 244 patients using a CDET gamma camera (2-dimensional system with 19 mm thick crystals). Additionally, from January 2000 to July 2002, 354 examinations were performed in 303 patients using PET (3-dimensional system with Nal crystals). RESULTS: Four hundred and seventy-three of the 644 examinations performed were evaluable on the basis of histological data (202 examinations) or more than 6 months of follow-up (273 examinations). The performances of the two systems were equivalent on a patient basis (sensitivity, specificity and accuracy of dedicated PET was 92%, 84% and 90%, respectively; and sensitivity, specificity and accuracy of CDET was 90%, 94% and 91%, respectively). On a site basis, a highly significant reduction in sensitivity was observed for lesions < or = 10 mm vs. > 10 mm with both PET and the CDET gamma camera, but no difference was observed between PET and CDET according to the size of the lesions. CONCLUSION: For detection of recurrent colorectal carcinoma, a 2-D coincidence gamma camera with 19 mm thick crystals and optimized acquisition and reconstruction parameters provides similar results in terms of accuracy, both per patient and per site, to those of an Nal PET camera.

Adult↗

PubMed2003

Positron emission tomography with [(18)F]FDOPA and [(18)F]FDG in the imaging of small cell lung carcinoma: preliminary results.

Small cell lung carcinomas (SCLC) express neuroendocrine markers, and dihydroxyphenylalanine (DOPA) is known to accumulate in neuroendocrine tumours. This study was performed with the aim of evaluating the uptake of 3,4-dihydroxy-6-(18)F-fluoro-phenylalanine ([(18)F]FDOPA) by SCLC, based on comparison with the results of fluorine-18 fluorodeoxyglucose ([(18)F]FDG) positron emission tomography (PET) and standard imaging procedures. [(18)F]FDG PET and [(18)F]FDOPA PET were performed on four patients with newly diagnosed SCLC. There was agreement between the results of [(18)F]FDOPA PET and [(18)F]FDG PET in four tumoural sites out of 11, whereas [(18)F]FDG PET and standard imaging procedures were in full agreement. A semi-quantitative analysis based on standardised uptake values (SUVs) was performed in order to compare [(18)F]FDG and [(18)F]FDOPA tumour uptake. The median [(18)F]FDG SUV(max) was 5.9 (with a 95% confidence interval from 4.4 to 9.2), while the median [(18)F]FDOPA SUV(max) was 1.9 (with a 95% confidence interval from 1.6 to 3.8). The difference between [(18)F]FDG SUV(max) and [(18)F]FDOPA SUV(max) was significant ( P<0.01). [(18)F]FDOPA PET appeared less sensitive than [(18)F]FDG PET and standard imaging procedures in the staging of SCLC. No clear relation between [(18)F]FDOPA uptake and positivity of neuroendocrine markers on immunohistochemistry emerged from these preliminary results; however, since [(18)F]FDOPA uptake may reflect better differentiation of the tumour, and possibly a better prognosis, this point warrants clarification in a larger study.

Adult↗