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Biomedical subjects

J E Freitas

Publications and source records attributed to J E Freitas.

At least 19 recordsLinked to original sources
PubMed1991

Guiding thyroid nodule management by fine-needle aspiration.

To determine the clinical value and cost effectiveness of fine-needle aspiration (FNA) in thyroid nodule management, a retrospective analysis of 945 consecutive patients subjected to FNA of cold nodules detected by clinical exam and Tc-99m pertechnetate thyroid scan between January 1, 1980, and December 31, 1987, was performed. After FNA, thyroid surgery was required in only 287 of 945 patients (30.4%). Of 87 cancers with satisfactory aspirates, 84 exhibited positive or suspicious cytology (sensitivity 96.6%). The predictive values for positive and negative cytology were 96.9% and 95.7%, respectively. Of 745 patients with known or presumed benign disease up to seven years of follow up, 642 showed benign cytologies (specificity 86.2%). The cancer removal rate (1980-1987) was higher with FNA and surgery than with surgery alone (P less than 0.001). The estimated cost saving of FNA in 1980-1987 approximates $564,000. FNA is of great value since it enables greater cancer detection in a cost-effective manner.

Adolescent↗
PubMed1991

The clinical utility of prostate-specific antigen and bone scintigraphy in prostate cancer follow-up.

To assess the value of serum prostate-specific antigen (PSA) in prostate cancer follow-up, we prospectively studied 107 consecutive patients with: (1) pathologically confirmed prostate cancer; (2) definitive prostatectomy and/or radiation therapy greater than or equal to 3 mo prior to bone scanning; and (3) one bone scan and serum PSA sampling within 3 mo of each other. The mean and range of patient follow-up since definitive therapy was 1.6 and 0.5-8 yr, respectively. Abnormal bone scans were correlated with pertinent radiographs. Of 107 bone scans, 16 demonstrated metastatic bone disease. A PSA value of less than or equal to 8 ng/ml excluded bone metastases with a predictive value of a negative test of 98.5%. Without radiographic correlation, abnormal bone scans rarely represented metastases if the PSA value was less than or equal to 8 ng/ml. In summary, serum PSA concentration determines the need for follow-up bone scanning and assists in scan interpretation in patients status post definitive therapy for prostate cancer.

Adenocarcinoma↗
PubMed1991

Clinical significance of the solitary functioning adrenal gland.

To assess the compensatory functional and anatomic changes in the remaining adrenal cortex after unilateral adrenalectomy or in the unaffected adrenal in patients with unilateral adrenal destruction by neoplasm, 17 patients with a single, functioning adrenal gland and normal indices of adrenocortical function, nine after adrenalectomy and eight with a unilateral, destructive adrenal lesion were studied with 131I-6 beta-iodomethyl-19-norcholesterol (NP-59) scintigraphy and computed tomography. Adrenal masses with a mean (+/- s.d.) diameter of 2.8 +/- 1.0 cm; (range 1-4 cm; 95% confidence interval (Cl), 2.5-3.1 cm) were identified by computed tomography in seven of nine patients in the remaining adrenal cortex at variable times (6.1 +/- 5.9 y; range 0.5-19 y) after unilateral adrenalectomy. Mean (+/- s.e.m.) NP-59 uptake was elevated (p less than 0.01) in both adrenalectomy and adrenal destruction groups, mean uptake (+/- s.e.m.) was 0.32% +/- 0.04% administered dose (95% Cl, 0.24%-0.4% administered dose) as compared to normal (0.16% +/- 0.05% administered dose, 95% Cl, 0.06%-0.26% administered dose). The remaining adrenal cortex may be anatomically abnormal after unilateral adrenalectomy and demonstrate compensatory, increased NP-59 uptake in the presence of overall, normal adrenocortical function.

Adosterol↗
PubMed1990

Scintigraphic endocrine mimicry.

The control of hormone secretion and substrate uptake by the thyroid and inner adrenal cortex is similar because both glands undergo hypothalamic-pituitary trophic hormone modulation and negative feedback by their respective major secretory products: thyroid hormone and cortisol, respectively. As a result of these parallel mechanisms of endocrine function, thyroidal accumulation of radioiodine or Tc-99m pertechnetate and adrenal cortical accumulation of I-131-6 beta-iodomethylnorcholesterol (NP-59) and other radiocholesterol analogs are strikingly similar. The patterns of imaging of these glands are thus functional maps of the process(es) of substrate accumulation and depict the endocrine pathophysiology of these glands in a variety of dysfunctional states. The well-recognized patterns of thyroid imaging can be shown analogous to those of the adrenal cortex.

Adosterol↗
PubMed1989

Adolescent varicocele: objective indications for treatment.

We measured the gonadotropin response pattern to the intravenous injection of luteinizing hormone-releasing hormone in 53 male adolescents 11 to 17 years old (average age 14.2 years) with a grade II to III varicocele. Volume loss of the testis ipsilateral to the varicocele of 2 cc or more was noted in 32 patients. Baseline serum levels of follicle-stimulating hormone, luteinizing hormone and testosterone were determined, and measured again at 15, 30 and 60 minutes following intravenous injection of luteinizing hormone-releasing hormone. Of the patients 23 had an exaggerated response pattern following luteinizing hormone-releasing hormone stimulation, including abnormally high post-stimulation levels of luteinizing hormone only in 6, follicle-stimulating hormone only in 4, and follicle-stimulating and luteinizing hormones in 13. No significant difference in mean age, testosterone levels or loss of testicular volume was noted between the abnormal and normal response groups. This study indicates that approximately 45 per cent of adolescents with a varicocele have evidence of testicular injury. The physical examination was of no value in predicting which patient with a varicocele would display evidence of testicular dysfunction. We suggest that the luteinizing hormone-releasing hormone stimulation test become a routine part of the evaluation of an adolescent with a varicocele.

Adolescent↗
PubMed1989

Phantom feet on digital radionuclide images and other scary computer tales.

Malfunction of a computer-assisted digital gamma camera is reported. Despite what appeared to be adequate acceptance testing, an error in the system gave rise to switching of images and identification text. A suggestion is made for using a hot marker, which would avoid the potential error of misinterpretation of patient images.

Aged↗
PubMed1985

Radionuclide diagnosis and therapy of thyroid cancer: current status report.

Thyroid cancer is uncommon, with an incidence of 10,300 new patients each year and a mortality of 1,100 patients each year. Patient survival correlates with many factors, including tumor pathology, age, primary lesion size, distant metastases, extent of surgery, and radioiodine therapy. Deaths from thyroid cancer may occur many years after diagnosis, and such an indolent course has hampered the analysis of the multiple treatment programs advocated. Thyroid imaging continues to play an important role in the initial detection and follow-up management of thyroid cancer, but the search for a specific tracer for the primary lesion continues. The complementary role of serum thyroglobulin and radioiodine in the follow-up of the thyroidectomized patient is discussed. Radioiodine therapy has proven effectiveness in those patients with radioiodine-avid distant metastases and/or regional metastases. Whether radioiodine ablation of residual thyroid bed activity is beneficial remains controversial.

Adenocarcinoma↗
PubMed1985

Limited significance of asymmetric adrenal visualization on dexamethasone-suppression scintigraphy.

To assess whether a single measurement of the adrenal uptake of 6 beta-[131I]-iodomethylnorcholesterol (NP-59) on constant dexamethasone suppression would allow discrimination of adenoma from normal and bilateral hyperplasia, the adrenal uptake of 6 beta-[131I]iodomethylnorcholesterol (NP-59) was determined in 50 patients with primary aldosteronism (30 adenoma, 20 hyperplasia) and in 13 with hyperandrogenism (six adenoma, seven hyperplasia). Bilateral adrenal NP-59 activity at 5 days was seen in 14 of 36 patients with adenoma (normal to adenoma ratio of greater than or equal to 0.5), whereas marked asymmetric uptake of NP-59 was seen in six of 27 patients with hyperplasia (uptake ratio of less than or equal to 0.5). Thus the level of adrenal NP-59 uptake does not alone serve to distinguish either adenoma from the normal, contralateral adrenal or the adrenal glands in bilateral hyperplasia in all cases. It appears that the pattern of adrenal imaging, early unilateral or early bilateral NP-59 activity (less than 5 days after NP-59 on 4 mg dexamethasone), best serves to separate adrenal adenoma from bilateral hyperplasia.

19-Iodocholesterol↗
PubMed1979

Absorbed dose to the human adrenals from lodomethylnorcholesterol (I-131) "NP-59": concise communication.

During the past 2 years, adrenal uptake percentage values were measured in more than 40 patients, using an external counting technique. They suggest that the absorbed dose to the adrenals is significantly less than 150 rads/mCIi previously estimated using concentration values from animal adrenals. The measured combined uptake percentage for both adrenals ranged from 0.15% to 0.52% in 21 patients without evidence of adrenal disease, with a mean of 0.33% +/- 0.1%; also from 0.22% to 1.5% in 22 patients with Cushing's disease, with a mean uptake of 0.78% +/- 0.35%. The absorbed dose to the adrenals was estimated to be 25 rads/mCi for patients without evidence of adrenal disease, and 57 rads/mCi for patients with Cushing's disease. Both values are calculated for the respective mean uptake percentages by using MIRD formalism.

Adosterol↗
PubMed1979

Adrenal imaging with iodomethyl-norcholesterol (I-131) in primary aldosteronism.

Twenty consecutive patients with primary aldosteronism (PAl) underwent dexamethasone suppression (DS) imaging with 6beta-[131I]-iodomethyl-19-norcholesterol (NP-59): A) to establish the value of the adrenal scan in distinguishing aldosteronomas from bilateral hyperplasia; b) to determine its ability to locate aldosteronomas when present; and c) to compare the efficacy of NP-59 in this current series against that reported previously with NM-145 in PAl. Ten of twenty patients had an aldosteronoma, five had histologically confirmed hyperplasia, and five had presumed hyperplasia. With NP-59, nine of ten tumors were correctly located (90%) , correct distinction between tumor and hyperplasia was possible in 90%, and a locating DS scan was specific for tumor in 90%. In a combined series of different patients with PAl imaged with NM-125, 21 of 25 tumors were correctly located (84%), tumor was distinguished from hyperplasia in 86%, and the specificity of the localizing scan was 92%. The imaging delay required from tracer injection to attainment of an interpretable scan averaged 2.7 days with NP-59 and 4.8 days with NM-145. In summary, no significant differences were noted in the clinical results achieved with these two agents. The preferred agent is NP-59, since the study can be completed with less average time delay than is possible with NM-145.

Adosterol↗
PubMed1979

The normal dexamethasone-suppression adrenal scintiscan.

To establish the parameters of adrenal imaging under dexamethasone suppression (DS), 18 normotensive, normal male volunteers underwent dexamethasone-suppression adrenal scintiscanning. Five control groups were established and given dexamethasone, either 8 mg for 2 days or 4 mg for 7 days before 6 beta-[131I]iodomethyl-norcholesterol (NP-59) administration. NP-59 was given in doses of 2, 1, or 0.5 mCi. Early visualization (3--5 days) of the adrenals was noted in the groups on the 8 mg DS regimen with either 1 or 2 mCi of NP-59. Late visualization (5--7 days) was noted in the groups that received 4 mg DS and either 2, 1, or 0.5 mCi of NP-59, respectively. The normal adrenal will demonstrate uptake of NP-59 under DS, and the duration of DS before imaging is the critical factor as to when discernible adrenal visualization will occur. The documentation of the noraml suppression interval on these DS regimens provides a basis for the correct diagnostic interpretation of adrenal hyperfunction as seen on the dexamethasone-suppression NP-59 adrenal scan.

Adosterol↗
PubMed1979

Thyroid scintigraphy with time-coded aperture.

Coded aperture imaging (CAI) and multiple-view pinhole imaging (MVPI) of the thyroid were compared in 19 patients to determine whether CAI's theoretical advantages of high resolution, high efficiency, freedom from distortion, accurate size representation, and tomographic presentation could be realized in the clinical setting, and to determine whether CAI offers any advantage over conventional MVPI. The coded aperture images were judged better than the pinhole images in five cases, equal in 13 cases, and worse in one case. The major problem with CAI was the long reconstruction time. Further development and an extended clinical trial appear warranted.

Humans↗
PubMed1979

Iodine-131: optimal therapy for hyperthyroidism in children and adolescents?

To assess the medium- to long-term effects of I-131 therapy of hyperthyroidism in children and adolescents, we studied 51 patients (age range 6--18; boys, 43 girls) treated with I-131 for Graves' disease with hyperthyroidism at the University of Michigan Medical Center (1951--1972). Patients received total doses ranging from 3 to 81.6 mCi. The mean followup period was 14.6 +/- 7.9 yr. Hyperthyroidism was effectively treated in 49 within 1 to 12 mo. One patient failed to respond to three treatment doses, and hyperthyroidism recurred in two patients: 2 and 11 yr after initial therapy. Of these three patients, two were treated by thyroidectomy and one was retreated successfully with I-131. There were no cases of thyroid cancer, other malignancies or leukemia. The patients' reproductive histories and the health of their offspring were as in the general population. At the time of study, the prevalence of hypothyroidism was 92%, with no recurrent goiters or thyroid nodules. Iodine-131 is found to be safe and effective treatment of hyperthyroidism in children and adolescents and should be the preferred mode of therapy.

Adolescent↗
PubMed1978

Adrenal hyperandrogenism: detection by adrenal scintigraphy.

Hyperandrogenism is a common endocrinopathy in women. Localization of the source of excess androgen production is mandatory for proper management. Ovarian hyperandrogenism has been implicated in the majority of patients studied, though the true prevalence of adrenal hyperandrogenism is not yet known. Adrenal scintigraphy is a simple non-invasive technique which detects adrenal functional abnormalities. The detection of adrenal hyperandrogenism by adrenal scintigraphy in three women with mild hirsutism is discussed.

Adenoma↗
PubMed1978

MEN type IIa syndrome: dilemmas in modern management.

With the use of newer techniques, the multiple endocrine neoplasm II-A syndrome can now be diagnosed early in its evolution. This article discusses the clinical course of the syndrome, the diagnostic modalities employed, and the therapeutic interventions required. An approach to the individual patient with this syndrome is presented.

Adolescent↗