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Sharon F Hain

Publications and source records attributed to Sharon F Hain.

12 recordsLinked to original sources
PubMed2005

Oral contrast medium in PET/CT: should you or shouldn't you?

PURPOSE: It has been suggested that the use of computed tomography (CT) positive contrast agents has led to attenuation-induced artefacts on 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET/CT) systems. Consequently, centres may withhold the use of such agents. Whilst there is theoretical evidence to support the aforementioned claim, the clinical relevance of the induced artefacts has not been widely established. Moreover, the potential benefits of bowel enhancement on PET/CT have yet to be formally evaluated. We therefore prospectively examined PET/CT studies to assess whether the use of oral contrast medium induces clinically relevant artefacts and whether the use of these agents is diagnostically helpful. METHODS: Over a 2-month period, 18F-FDG PET/CT images were prospectively reviewed from 200 patients following Gastrografin administration 2 h prior to examination. Both a radiologist and a nuclear medicine physician reviewed the images for contrast medium-mediated clinically relevant artefacts. Artefacts were sought on the CT attenuation-corrected images and were compared with the appearance on non-attenuated-corrected images. The number of examinations in which the oral contrast aided image interpretation was also noted. RESULTS: There were no oral contrast medium-induced clinically significant artefacts. In 38 of the 200 patients, oral contrast aided image interpretation (owing to differentiation of mass/node from bowel, discrimination of intestinal wall from lumen or definition of the anatomy of a relevant site). In 33 of these 38 patients, the anatomical site of interest was the abdomen/pelvis. CONCLUSION: The use of oral contrast medium in 18F-FDG PET studies should not be withheld as it improves image interpretation and does not produce clinically significant artefacts.

Abdominal Neoplasms↗
PubMed2005

Positron emission tomography in cancer of the head and neck.

The use of positron emission tomography (PET) has increased in oncology and in the assessment of head and neck tumours, where it is most useful for recurrent disease. It has good sensitivity and specificity for diagnosis and staging but is generally not necessary except in difficult cases. Quantitative measures of uptake on PET at diagnosis and after treatment do seem to have prognostic value independent of other information about the tumour and so PET may influence management. It also has a role in the identification of an unknown primary site and of synchronous primaries and metastases (often missed by other imaging). Fusion imaging with magnetic resonance (MRI) or computed tomography (CT) adds a new dimension with improved value for each technique.

Carcinoma, Squamous Cell↗
PubMed2005

Localization of parathyroid adenomas using 11C-methionine positron emission tomography.

BACKGROUND AND AIM: In symptomatic hyperparathyroidism, pre-surgical localization of the suspected site of adenoma is desirable. All widely available techniques may have difficulty in localizing the site. The aim of this study was to determine whether 11C-methionine positron emission tomography (PET) could accurately localize parathyroid adenomas in patients in whom conventional imaging had failed. PATIENTS AND METHODS: Fifty-one patients presenting with hyperparathyroidism, and in whom other imaging techniques had failed to definitely identify the site of adenoma, were reviewed retrospectively after 11C-methionine PET scanning. Patients were followed up by surgical histology, or clinically if surgery was not performed. RESULTS: 11C-Methionine PET scanning was found to have a sensitivity of 83%, a specificity of 100% and an accuracy of 88% in successfully locating parathyroid adenomas. Most false negatives were due to adenomas in the lower mediastinum that was outside the area of scanning. CONCLUSIONS: 11C-Methionine PET is a reliable and highly accurate technique for localizing parathyroid adenomas in patients in whom conventional imaging techniques have failed. It is necessary to image to the level of the lower mediastinum.

Adenoma↗
PubMed2003

Validation of ultrafiltration as a method of measuring free 99mTc-MDP.

UNLABELLED: Quantitative studies of the kinetics of (99m)Tc-methylene diphosphonate ((99m)Tc-MDP) in metastatic and metabolic bone disease require the measurement of free tracer in plasma to derive the input function. Several methods of measuring free (99m)Tc-MDP have been described including ultrafiltration, precipitation using trichloroacetic acid, and a direct in vivo measurement based on the assumption that free MDP is cleared through the kidneys by glomerular filtration. The aim of this study was to validate ultrafiltration as a convenient and accurate method of measuring the free fraction of (99m)Tc-MDP by comparing it with the glomerular filtration rate (GFR) method. A second aim was to measure the percentage of free (99m)Tc-MDP in a cross-section of patients using ultrafiltration to determine the interpatient variability and, therefore, whether individual measurements are required for bone kinetic studies. METHODS: In study 1, 10 volunteers (7 women, 3 men; mean age, 37 y; range, 26-55 y) were injected with 3 MBq (99m)Tc-MDP and 3 MBq (51)Cr-ethylenediaminetetraacetic acid, and multiple blood and urine samples were taken between 0 and 4 h. Plasma samples were spun in 5-, 10-, and 30-kDa filters and counted in a gamma-counter. In study 2, 51 randomly selected patients (26 women, 25 men; mean age, 66 y; range, 31-87 y) attending our department for a routine bone scan were injected with 600 MBq (99m)Tc-MDP, and 4 blood samples were taken between 0 and 4 h and spun in 10-kDa filters. RESULTS: In study 1, the mean percentages (+/-SD) of free (99m)Tc-MDP at 5 min and 4 h after injection measured using the 10-kDa filters were 83.1% +/- 3.4% and 44.0% +/- 10.0%. The mean ratios (+/-SEM) of the free (99m)Tc-MDP in ultrafiltrate compared with the GFR method for the 5-, 10-, and 30-kDa filters were 0.894 +/- 0.010, 0.943 +/- 0.009, and 0.987 +/- 0.010. In study 2, the mean percentages (+/-SD) of free (99m)Tc-MDP at 15 min and 4 h were 75.3% +/- 8.0% and 48.8% +/- 9.5%, with a precision error of 2.3%. The percentages of free MDP at 150 min and 4 h were significantly correlated with GFR but not with serum albumin. CONCLUSION: Ultrafiltration provides an accurate method of evaluating free (99m)Tc-MDP in plasma for bone kinetic studies. The results from both the healthy volunteers in study 1 and the patients in study 2 show that protein binding varied with time and showed significant differences between individuals that were partly dependent on GFR. It is thus necessary to measure individual protein binding values for bone kinetic studies.

Adult↗
PubMed2002

Nuclear medicine studies in metabolic bone disease.

The principal application of nuclear medicine in metabolic bone disease is the isotope bone scan. Often, it is not a diagnostic tool but can be useful in clarifying the nature of a clinical problem. The best-established role for the bone scan in metabolic bone disease is in Paget's disease, in which it is diagnostic, provides definition of the extent of disease, and probably reflects disease activity. The isotope bone scan is also important in osteoporosis, for which it is not diagnostic but may often provide useful information to confirm that fracture has occurred, determine the age of the fracture, identify unsuspected fractures, and identify other causes for pain, for example, facet joint disease. The bone scan is less useful in other metabolic bone diseases, for example, renal osteodystrophy and osteomalacia, but will often have a characteristic appearance, with several metabolic features. The degree of positivity of the scan generally relates to the severity of the hyperparathyroidism. In patients with metabolic bone disease, other specific clinical problems may arise, such as osteomyelitis or avascular necrosis, and the bone scan may be diagnostic in these conditions. Nuclear medicine techniques are also of value in hyperparathyroidism and to localize the site of the adenoma where surgical treatment is being considered; the use of technetium Tc 99m sestamibi is now routine. More recently, positron emission tomography (PET) scanning has been found to be helpful in the more difficult cases.

Bone Diseases, Metabolic↗
PubMed2002

F-18 FDG-positron emission tomographic scanning and Wegener's granulomatosis.

Wegener's granulomatosis is a necrotizing granulomatous vasculitis that mainly affects the upper airways, lungs, and kidneys. Autoimmune mechanisms are hypothesized to play a role in the pathophysiology of the disease. F-18 fluorodeoxyglucose-positron emission tomographic scanning is normally used to differentiate benign from malignant disease as a result of differences in glucose metabolism. The authors present a case of Wegener's granulomatosis in which F-18 fluorodeoxyglucose-positron emission tomographic scanning yielded a false-positive result.

Adenocarcinoma↗
PubMedDate not supplied

Renal imaging.

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Adolescent↗