PubMed Health⌕ Search

Biomedical subjects

Chuong Bui

Publications and source records attributed to Chuong Bui.

8 recordsLinked to original sources
PubMed2006

Multimodality imaging of malignant pheochromocytoma.

Pheochromocytomas offer the opportunity to explore multiple pathophysiological mechanisms through functional imaging. MIBG scintigraphy and PET scanning with tracers of the sympathetic nervous system are based on uptake of catecholamines and catecholamine-like compounds by hNET, the human norepinephrine transporter. In-111 pentetreotide scanning involves the imaging of somatostatin receptors on the cellular surface of tissues. FDG PET scanning examines the transport and incorporation of FDG into cells. We present a patient with malignant pheochromocytoma who underwent multitracer imaging to characterize the tumor and probe its pathophysiology to direct a therapeutic approach. This case underscores the inherent difficulties in the diagnosis and localization of malignant pheochromocytomas. Multiple approaches to functional and anatomic imaging may be required to fully delineate the extent of disease and similarly to direct radionuclide-based therapy.

Adrenal Gland Neoplasms↗
PubMed2005

Thyroid dysfunction during interferon alpha therapy for chronic hepatitis C.

Interferon-alpha therapy is well known to induce a wide range of thyroid dysfunction. A 22-year-old woman with chronic hepatitis C developed overt hyperthyroidism while on interferon-alpha and ribavirin therapy. Tc-99m thyroid scintigraphy demonstrated virtually absent tracer uptake consistent with subacute thyroiditis. Ten months after starting antiviral therapy, overt hyperthyroidism recurred. Repeat thyroid scintigraphy revealed diffusely increased tracer uptake throughout the thyroid gland consistent with Graves disease. This is an unusual case of 2 forms of hyperthyroidism-confirmed scintigraphically and occurring in the same patient over time while on interferon-alpha therapy.

Adult↗
PubMed2003

Randomised, double blind, placebo controlled crossover trial of sustained release morphine for the management of refractory dyspnoea.

OBJECTIVE: To determine the efficacy of oral morphine in relieving the sensation of breathlessness in patients in whom the underlying aetiology is maximally treated. DESIGN: Randomised, double blind, placebo controlled crossover study. SETTING: Four outpatient clinics at a hospital in South Australia. PARTICIPANTS: 48 participants who had not previously been treated with opioids (mean age 76, SD 5) with predominantly chronic obstructive pulmonary disease (42, 88%) were randomised to four days of 20 mg oral morphine with sustained release followed by four days of identically formulated placebo, or vice versa. Laxatives were provided as needed. MAIN OUTCOME MEASURES: Dyspnoea in the morning and evening as shown on a 100 mm visual analogue scale, quality of sleep, wellbeing, performance on physical exertion, and side effects as measured at the end of the four day treatment period. RESULTS: 38 participants completed the study; three withdrew because of definite and two because of possible side effects of morphine (nausea, vomiting, and sedation). Participants reported significantly different dyspnoea scores when treated with morphine: an improvement of 6.6 mm (95% confidence interval 1.6 mm to 11.6 mm) in the morning and of 9.5 mm (3.0 mm to 16.1 mm) in the evening (P = 0.011 and P = 0.006, respectively). During the period in which they were taking morphine participants also reported better sleep (P = 0.039). More participants reported distressing constipation while taking morphine (9 v 1, P = 0.021) in spite of using laxatives. All other side effects were not significantly worse with morphine, although the study was not powered to address side effects. CONCLUSIONS: Sustained release, oral morphine at low dosage provides significant symptomatic improvement in refractory dyspnoea in the community setting.

Administration, Oral↗
PubMed2002

Functional scintigraphy of the adrenal gland.

Over the last 30 years nuclear medicine imaging of the adrenal gland and its lesions has been achieved by the exploitation of a number of physiological characteristics of this organ. By seeking and utilising features which are quantitatively or qualitatively different from those of the adjacent tissues, functional depiction of the adrenal gland and its diseases, which in most cases retain the basic physiology of their tissue of origin, including both the cortex and the medulla, are now a useful clinical reality. Agents widely used in clinical practice include: (a) uptake and storage of radiolabelled cholesterol analogues via the low density lipoprotein (LDL) receptor and cholesterol ester storage pool in the adrenal cortex ((131)I-6-beta-iodomethyl-norcholesterol, (75)Se-selenomethyl-norcholesterol); (b) catecholamine type I, presynaptic, uptake mechanism and intracellular granule uptake and storage mechanism in the adrenal medulla and extra-adrenal paraganglia ((131)I-, (123)I- and (124)I-meta-iodo-benzyl-guanidine (MIBG), (18)F-metafluoro-benzyl-guanidine); (c) cell surface receptor binding of peptides/neurotransmitters/modulators such as for the family of five subtypes of somatostatin receptors ((123)I-tyr-octreotide, (111)In-DTPA-octreotide, (111)In-DOTA-octreotide and many others); (d) although not specific for the adrenal gland, increased glycolysis by tumours, particularly the most malignant varieties, (18)F-2-fluoro-d-deoxyglucose can thus be expected to depict certain malignant lesions such as malignant pheochromocytomas (particularly the minority which are not detected by MIBG) and adrenal incidentalomas (particularly when they occur in patients with known extra-adrenal malignancies). There are a variety of adrenal tissue characteristics with potential for exploitation but which are not currently in clinical use, and which may, nevertheless, have potential as imaging agents. These include: (a) inhibitors of adrenal cortical steroid hormone synthesis enzymes (e.g. radiolabelled analogues of metyrapone); (b) radiolabelled lipoproteins which bind to adrenocortical LDL receptors; (c) inhibitors of catecholamine biosynthesis enzymes (e.g. radiolabelled analogues of tyrosine and related amino acids); (d) cell surface receptors for various peptides and hormones which may be over-expressed on adrenal cortical or adrenal medullary tumours (e.g. radiolabelled analogues of ACTH on adrenocortical cells of zona fasciculata or zona glomerulosa origin, neurotransmitter/hormone message peptides binding to cell surface receptors such as bombesin, vasoactive intestinal polypeptide, cholecystokinin and opiate peptides); (e) the adrenal cortex can also synthesise cholesterol ab initio from acetate, and preliminary studies with (11)C-acetate positron emission tomography have shown interesting results.

Adrenal Gland Diseases↗
PubMedDate not supplied

High incidence of chest malignancy detected by FDG PET in patients suspected of recurrent squamous cell carcinoma of the upper aerodigestive tract.

OBJECTIVE: To determine the incidence of chest neoplasms detected by FDG PET in patients with previously treated squamous cell head and neck cancer (HNC), being evaluated for possible recurrent disease. METHODS: This is a retrospective review of 41 patients (M = 29, F = 12: average age = 58 years) with previously treated HNC who underwent FDG PET of the neck and chest as part of routine evaluation for locoregional and/or distant recurrence. Thirty-four of 41 patients had advanced stage III or IV HNC. All FDG PET studies were reviewed by dedicated nuclear medicine physicians, including evaluation for abnormal uptake in the chest. The chest FDG findings were correlated with serial chest radiographs or chest CT. The occurrence rate of incidental chest malignancy was determined and based on characteristic imaging findings, biopsy, and/or clinical course. RESULTS: Twelve of 41 patients had abnormal FDG uptake in the lungs and/or mediastinum. Ten of 12 patients were found to have neoplasms that could represent either metastases or a new lung primary. Five of these 10 were unsuspected neoplasms prior to FDG PET. The other 2/12 FDG PET scans in the chest were false positive. There was one false-negative FDG PET, with subsequent PET and CT demonstrating pulmonary metastases. Overall, there was a 27% incidence of chest malignancies in patients with advanced HNC being evaluated for possible recurrence. CONCLUSION: Our study demonstrated a chest malignancy in 1 out of 4 patients with advanced HNC being evaluated for locoregional and/or distant spread. Fifty percent were unsuspected prior to FDG PET. This result suggests that FDG PET of the lungs should be routinely included in the evaluation of high-risk patients.

Adult↗