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Biomedical subjects

Anca M Avram

Publications and source records attributed to Anca M Avram.

10 recordsLinked to original sources
PubMed2006

Adrenal gland scintigraphy.

There is no question that high-resolution imaging techniques have revolutionized the approach to diagnostic imaging. Computed tomography (CT) and magnetic resonance imaging provide exquisite images of the adrenal glands and offer the best initial imaging approach in the evaluation of patients with suspected adrenal disease. However, an assessment of anatomy is only a portion of the diagnostic effort, which begins with a biochemical evaluation to establish the presence of adrenal gland dysfunction. With a confirmed biochemical diagnosis in hand, a logical and stepwise diagnostic approach can be tailored to a particular patient. Where scintigraphy fits in the evaluation of diseases of the adrenal cortex and medulla in the context of high-resolution imaging and which radiopharmaceuticals should be deployed has changed substantially during the last 2 decades. Adrenal functional imaging has evolved from classic planar scintigraphy to single-photon emission computed tomography (SPECT) and positron emission tomography (PET) using tracers that, by targeting specific metabolic or synthetic processes within the gland, have depicted adrenal pathophysiology. New PET/CT and SPECT/CT technologies integrate anatomic and functional information and redefine the radiotracer principle in the larger context of high resolution anatomic imaging.

3-Iodobenzylguanidine↗
PubMed2006

Differentiation between carcinoid and sarcoid with F-18 FDG PET and In-111 pentetreotide.

A patient who presented with weight loss and recurrent left lower lobe pneumonia was diagnosed with endobronchial carcinoid. Chest CT scan demonstrated extensive mediastinal and hilar lymphadenopathy suggesting stage IIIB disease, but radionuclide imaging with In-111 pentetreotide and F-18 FDG PET diagnosed 2 distinct pathologic processes based on functional differences between neuroendocrine tumors (expressing somatostatin receptors) and sarcoidosis (intensely FDG-avid). The possible association of carcinoid with sarcoidosis and sarcoid-like reactions in regional lymph nodes should always be considered, and the staging process should include both anatomic and functional imaging and biopsy confirmation of suspected metastatic lesions.

Adult↗
PubMed2006

The so-called stunning of thyroid tissue.

UNLABELLED: When thyroid tissues exhibited concentrations of therapeutic (131)I that appeared to be less than that predicted by data from the preceding diagnostic (131)I, the phenomenon was called stunning. We hypothesized that stunning arose from the early effects of the therapeutic dose of (131)I and that the initial uptake of (131)I, observed within the first day, was not impaired by the diagnostic dose. METHODS: The hypothesis was tested by 2 types of studies. In each type, the fractional concentrations of (131)I in residual neck thyroid tissues of patients with papillary thyroid carcinoma were quantified. In the first study, fractional concentrations of diagnostic and therapeutic (131)I were measured at 2 d, a time when stunning has been observed, and expressed as ratios of radioactivity: therapeutic/diagnostic (Rx/Dx). Three different doses of diagnostic (131)I were prescribed to assess a dose response. In the second study, patients were prospectively recruited and tested to record disappearances of radioactivity from thyroid tissues. Diagnostic doses were 1.0 mCi (37 MBq) in all; therapeutic doses were 150 and 30 mCi (5,550 and 1,110 MBq), each to half of the patients. The disappearance curves were extrapolated to the period between 0 and 1 d, an interval when maximum uptake of ingested (131)I would be expected. The fractional concentrations of (131)I at 2 d and at 0-1 d were compared in terms of Rx/Dx ratios to assess changes at each time point. RESULTS: In the first study, after diagnostic doses of 2, 1, and 0.5 mCi (74, 37, and 18.5 MBq), mean 2-d Rx/Dx values in 24, 29, and 17 patients were 0.35, 0.50, and 0.46 (P = 0.087). Of all patients, 74% exhibited Rx/Dx <0.6. In the second study, 6 of 10 patients exhibited disappearance curves of (131)I in which Rx/Dx was <0.6 at 2 d; 5 of the 6 had Rx/Dx values >0.97 at the 0- to 1-d point. In 1 patient the Rx/Dx was 0.54 at 2 d and 0.66 at the earlier time point. The other 4 patients had disappearance curves in which Rx/Dx values were >1.0 throughout or were above 0.6 and did not greatly change. CONCLUSION: Two days after the administration of (131)I, the mean fractional concentration of radioactivity in thyroid tissues after a therapeutic dose is <60% of the diagnostic dose in most patients, but no correlation of Rx/Dx with the mCi in the diagnostic dose was seen. In 5 of 6 patients in whom the Rx/Dx at 2 d was <0.6, the maximum fractional concentrations of therapeutic and diagnostic (131)I (i.e., the tissue uptakes during the first day) were similar; this pattern was most apparent after therapies with 150 mCi. These results support the hypothesis that "stunning" of thyroid tissues, often observable by 2 d, is primarily the consequence of early destructive effects from therapeutic (131)I.

Adolescent↗
PubMed2005

The clinical role of CT/PET in oncology: an update.

FDG-PET imaging has significantly altered the workup of the oncologic patient. With the introduction of combined FDG-PET/CT scanners, there has been a dramatic improvement in lesion detection, lesion characterization and accurate lesion localization. As attenuation correction can be attained with the CT images, PET exam times have been dramatically reduced, by as much as 50% in many instances. In this overview we briefly outline the advantages of CT/PET in oncology especially in diagnosis and clinical management of the common tumor types for which it is mainly used.

Colonic Neoplasms↗
PubMed2005

Endogenous circulating ghrelin does not mediate growth hormone rhythmicity or response to fasting.

GH secretory profiles in humans are pulsatile and exhibit nocturnal elevation during the early hours of sleep. Fasting augments GH output and rhythmicity. Ghrelin was suggested to exhibit nocturnal increases and to rise in response to nutritional deprivation. We examined whether ghrelin may be an underlying mechanism of GH rhythmicity and response to fasting. We studied nine young healthy subjects during normal feeding and after 2 d of complete fasting. Plasma GH was measured every 10 min, and plasma total and active ghrelins were measured every 20 min. Fasting augmented mean daily plasma GH (1.47 +/- 0.25 vs. 3.30 +/- 0.6 microg/liter; P = 0.012). Neither mean daily total ghrelin (4.19 +/- 0.64 vs. 4.35 +/- 0.74 microg/liter; P = 0.75) nor mean daily active ghrelin (0.13 +/- 0.02 vs. 0.13 +/- 0.02 microg/liter; P = 0.34) changed as a result of fasting. All subjects exhibited nocturnal augmentation of GH secretion; there were no corresponding nocturnal increases in either total or active ghrelin concentrations. Similarly, cross-correlation analysis failed to find any relation between GH and ghrelin pulses. We conclude that ghrelin is unlikely to be of importance in the generation of rhythmic or nutritionally mediated GH secretion.

Adult↗
PubMed2004

Cryptococcal thyroiditis and hyperthyroidism.

We report a case of cryptococcal thyroiditis presenting with hyperthyroidism that evolved through a transient euthyroid phase to hypothyroidism and finally recovered to normal function. This four-phase clinical presentation is similar to that of subacute thyroiditis, and it is unusual in the setting of infectious nonviral thyroiditis. Cryptococcal thyroiditis is rare; only three cases have been reported. Our patient is the first who survived the disseminated cryptococcal infection with thyroid involvement, thus enabling longitudinal clinical and endocrinologic follow-up.

Adult↗
PubMed2004

Choroidal and skin metastases from papillary thyroid cancer: case and a review of the literature.

A patient with widely metastatic papillary thyroid cancer who had been previously treated with (131)I and external beam radiation presented with purple nodular lesions on his face and scalp. On biopsy, the nodules were papillary carcinoma with cells that stained for thyroglobulin. Subsequently he developed decreased left eye visual acuity, and fundoscopy revealed lesions typical of choroidal metastases. Dermal and choroidal metastases of papillary thyroid carcinoma are both rare. However, the significance of these clinical manifestations may be overlooked and ignored unless the diagnosis is considered. New skin nodules or visual acuity decline in a patient with papillary thyroid cancer may represent manifestations of distant metastatic disease and should prompt thorough evaluation with dermatological examination and fundoscopy. Choroidal and skin metastases have almost always occurred in patients with advanced disease, but initial presentation with these lesions is possible, and in such instances a thorough search for additional sites of metastatic disease is recommended. Occasionally such metastases may respond to (131)I therapy or external beam radiation.

Carcinoma, Papillary↗