Quantitative computed tomography measurements of bone mineral density in prepubertal children with congenital hypothyroidism treated with L-thyroxine

Low bone density (BD) has been reported in patients with hyperthyroidism. Whether or not levothyroxine (LT4) therapy in children with congenital hypothyroidism (CH) affects BD is unclear. Medical records of 45 patients with various etiologies of CH who had at least one BD measurement (32 female, mean age 7.6 +/- 2.6 years) were reviewed. The mean LT4 dose was 3.6 +/- 0.88 microg/kg/day. Cancellous bone density (CaBD) was measured by quantitative computed tomography (CT) in all 45 patients and 20 had measurements of cortical bone density (CoBD), cross-sectional area (CSA) and cortical bone area (CBA) of the femur. TSH levels were considered partially or completely suppressed when values were <1.0 or <0.5 microIU/ml, respectively. The control group consisted of age- and gender-matched healthy children. No significant differences were found in CaBD, CoBD, CSA, or CBA between patients with CH and controls. There were no significant differences between initial and subsequent BD measurements. No correlations were found between CaBD and etiology of CH, dose or duration of LT4 therapy, or serum TSH. In pre-pubertal children with CH, LT4 appears to have no significant effect on BD. Moreover, absence or hypoplasia of the thyroid parenchyma appears to have no significant impact on bone formation within the first 10 years of life.

Myocardial contractility and total arterial stiffness in patients with overt hyperthyroidism: acute effects of beta1-adrenergic blockade

OBJECTIVES

To ascertain whether myocardial contractility and total arterial stiffness are significantly altered in human thyrotoxicosis, and to what extent they are affected by acute beta(1)-adrenergic blockade.

METHODS

Doppler-echocardiography was used to assess left ventricular (LV) structure and function, hemodynamics and total arterial stiffness in untreated overt hyperthyroid patients before and 2 h after 5 mg bisoprolol given orally compared with age- and sex-matched healthy euthyroid controls.

RESULTS

Compared with controls, untreated patients (n=20) had a higher heart rate (HR) and LV stroke index (SI), which were associated with higher pulse pressure (PP), larger LV end-diastolic volume index (EDVI, an index of preload,+11%, P<0.05), marginally increased stress-corrected LV midwall fractional shortening (MWS, an index of myocardial contractility,+5%; P=0.066), and shorter isovolumic relaxation time (IVRT). These changes resulted in a higher cardiac index (CI) and a lower systemic vascular resistance (SVR), which were associated with fairly normal mean blood pressure (BP) but higher PP/stroke volume (an index of total arterial stiffness,+29%; P<0.01). After bisoprolol, compared with controls, the randomly treated patients (n=10) had comparable HR but additionally increased SI; PP remained enhanced, EDVI was further enlarged (+26%, P<0.001), stress-corrected MWS was substantially unchanged, and IVRT remained shorter. Overall, these effects attenuated the high-output state, which was associated with normalization of PP/stroke volume without changes of mean BP.

CONCLUSIONS

In human overt hyperthyroidism, myocardial contractility does not play a major role in increasing LV performance, which is instead predominantly sustained by increased preload with enhanced LV diastolic function. In addition, human thyrotoxicosis is associated with increased total arterial stiffness despite fairly normal mean BP. In this scenario, acute beta(1)-adrenergic blockade blunts the cardiovascular hyperkinesia predominantly by slowing HR - a process that is associated with normalization of total arterial stiffness.

Design and tests of a portable mini gamma camera

Design optimization, manufacturing, and tests, both laboratory and clinical, of a portable gamma camera for medical applications are presented. This camera, based on a continuous scintillation crystal and a position-sensitive photomultiplier tube, has an intrinsic spatial resolution of approximately 2 mm, an energy resolution of 13% at 140 keV, and linearities of 0.28 mm (absolute) and 0.15 mm (differential), with a useful field of view of 4.6 cm diameter. Our camera can image small organs with high efficiency and so it can address the demand for devices of specific clinical applications like thyroid and sentinel node scintigraphy as well as scintimammography and radio-guided surgery. The main advantages of the gamma camera with respect to those previously reported in the literature are high portability, low cost, and weight (2 kg), with no significant loss of sensitivity and spatial resolution. All the electronic components are packed inside the minigamma camera, and no external electronic devices are required. The camera is only connected through the universal serial bus port to a portable personal computer (PC), where a specific software allows to control both the camera parameters and the measuring process, by displaying on the PC the acquired image on "real time." In this article, we present the camera and describe the procedures that have led us to choose its configuration. Laboratory and clinical tests are presented together with diagnostic capabilities of the gamma camera.

Thyroid function and carotid wall thickness

Decreased serum TSH levels predict vascular mortality in older people. There is a need to investigate mechanisms that could explain this association. This study was designed to investigate the relationship between thyroid function and the carotid intima-media thickness (IMT). The Study of Health in Pomerania is a population-based survey in Germany. Data from 2086 individuals at least 45 yr old with carotid ultrasound and without known thyroid disorders were analyzed. Twenty-nine participants (1.4%) had elevated serum TSH levels, 300 (14.4%) had decreased serum TSH levels, and 12 (0.6%) participants were hyperthyroid. A linear relationship between thyroid function and IMT was found. The highest IMT values were observed in participants with hyperthyroidism, the lowest in subjects with elevated serum TSH levels (P < 0.01). A multivariable regression analysis identified thyroid function as an independent risk factor for increased IMT. Other risk factors for increased IMT included male gender, advanced age, diabetes mellitus, current smoking, and the use of antihypertensive medication; increased pulse pressure, serum low-density cholesterol, and total cholesterol/high-density lipoprotein ratio; as well as a decreased heart rate and a positive history of myocardial infarction. We conclude that there is an independent association between thyroid function and the IMT of the carotid artery.

Medullary thyroid carcinoma associated with hyperthyroidism: a case report and review of the literature

Thyroid cancer is occasionally associated with hyperthyroidism. Papillary thyroid carcinoma is the most frequently reported histologic type followed by follicular thyroid carcinoma. Medullary thyroid carcinoma (MTC) has been rarely described in association with Graves' disease or other forms of hyperthyroidism. To our knowledge, only 14 cases have been described in which MTC was associated with hyperthyroidism. We report a 70-year-old male who had a clinically significant MTC discovered in the course of diagnostic work-up for hyperthyroidism. We also summarize the clinical features of the other 14 reported cases.

Thyrotoxic adenoma followed by atypical hyperthyroidism due to struma ovarii: clinical and genetic studies

OBJECTIVE

Atypical forms of hyperthyroidism represent a diagnostic challenge for clinicians. Struma ovarii is an ovarian teratoma and constitutes a rare cause of ectopic thyroidal hormonal production. We describe a case of struma ovarii that combined two different sources of hyperthyroidism in the same patient and report genetic studies in order to contribute a better understanding of the autonomy and tumorigenesis of the struma ovarii.

CASE REPORT

A 73-year-old nulliparous woman presented a thyroid toxic adenoma that was successfully treated with 10 mCi radioiodine. Unexpectedly, a new onset of hyperthyroidism prompted us to look for a second etiology. A whole-body scan with (123)I detected a pelvic hyperfixation suggesting struma ovarii, and a thyroid differentiated left ovarian teratoma 3 cm in size was surgically removed. We screened for mutations of thyroid-stimulating hormone receptor and Gs-alpha protein genes, as these mutations are common in thyroid adenomas. We did not identify any mutations. Androgen receptor study demonstrated a monoclonal status. Comparative genomic hybridization did not reveal any chromosomal abnormality. However, loss of heterozygosity analysis showed several structural abnormalities, compared with the majority of benign ovarian teratomas, which show a normal karyotype.

CONCLUSIONS

This is the first well-documented report of thyrotoxic struma ovarii revealed after treatment of a single thyroid toxic adenoma. We have shown in this case that struma ovarii originates from a single germ cell, and, albeit benign, this tumor presents several chromosomal abnormalities. Struma ovarii-induced hyperthyroidism is likely to be mediated by mechanisms different from those of the classical thyroid toxic adenoma.

Thyroid cancer in patients with hyperthyroidism

OBJECTIVE

The coexistence of hyperthyroidism and thyroid cancer is considered a rare event. With the aim of assessing the clinical relevance of this association, we have retrospectively analyzed the incidence of thyroid cancer in 425 hyperthyroid patients seen and treated by surgery in our institutions.

METHODS

Among these hyperthyroid patients, we observed 241 (56.7%) cases of multinodular toxic goiter, 120 (28.3%) of uninodular toxic goiter and 64 (15%) cases of Graves' disease.

RESULTS

Thyroid cancer was diagnosed in 7 (1.65%) hyperthyroid patients. Histological examination revealed the presence of papillary carcinoma in 5 cases and follicular carcinoma in 2 cases. Neoplasia was detected in 4 patients with nodular toxic goiter and in 3 with uninodular toxic goiter. None of the patients with Graves' disease had thyroid cancer. During the follow-up of 74 months (range 4-154), there were no deaths or any recurrences.

CONCLUSION

Although the occurrence of thyroid cancer in hyperthyroid patients is a rare event, the presence of a 'cold' nodule in a hyperfunctioning thyroid should be carefully evaluated to exclude the presence of concurrent malignancy.

Follicular carcinoma of the thyroid with hyperthyroidism. A case report

BACKGROUND

Follicular carcinoma of the thyroid in association with hyperthyroidism is rare. The malignant lesion may remain occult for a long time. Certain clinical and cytologic features may be helpful in raising the alarm.

CASE

An elderly male with a history of occupational exposure to X rays, long-standing toxic multinodular goiter and clinical hyperthyroidism presented with a rapidly enlarging mass in the neck. Cytologic smears showed a prominent microfollicular pattern, scanty colloid, anisonucleosis and nuclear overlapping. The noteworthy feature was the presence of marginal vacuoles. The cytologic diagnosis of follicular neoplasm with highly suggestive malignancy was made. Subsequently, multiple pulmonary nodules provided radiologic evidence of possible metastatic spread.

CONCLUSION

This case report demonstrates the rare association of follicular carcinoma of the thyroid with hyperthyroidism and analyzes certain high-risk clinical and cytologic features to be considered in the follow-up of long-standing hyperfunctioning multinodular goiter.

Apoptosis: its pathophysiology and monitoring. The role of apoptosis in the radioiodine therapy of hyperthyroidism

The review aims to give an up to date understanding of the mechanisms of apoptosis (programmed cell death), the methods of detecting apoptosis, in particular with regard to imaging such changes non-invasively. Radioiodine (I-131) is a gamma and beta emitting radionuclide and is commonplace in the treatment of hyperthyroidism. I-131 therapy relies on the destruction of thyroid tissue by beta radiation, and such destruction is proposed to be partly as a result of apoptosis. The review undertakes to explore and provoke research into the mechanisms of thyroid cell destruction by I-131, and whether such changes are able to be detected or monitored. Current knowledge concerning apoptosis in the thyroid gland in diseased states (including cancer) are described. The clinical significance of monitoring and modifying apoptosis are emphasized. Furthermore, overt and late destruction of thyroid tissue following I-131 therapy requires elaboration, and the relevance of detecting and modifying thyroid cell apoptosis following I-131 are questioned.

Percutaneous ultrasound-guided radiofrequency heat ablation for treatment of hyperthyroidism in cats

OBJECTIVE

To determine efficacy and safety of percutaneous radiofrequency heat ablation for treatment of hyperthyroidism in cats.

DESIGN

Prospective study.

ANIMALS

9 cats.

PROCEDURE

Hyperthyroidism was diagnosed via clinical signs and high serum total (TT4) and free thyroxine (fT4) concentrations. One or 2 hyperfunctional cervical thyroid nodules were detected by use of scintigraphy and ultrasonography. If cats had 1 abnormal thyroid lobe, heat ablation was performed on that lobe; if cats had 2 abnormal lobes, heat ablation was applied to the larger lobe. Overall, heat ablation was performed 14 times in the 9 cats. Clinical signs and serum TT4, fT4, and calcium concentrations were monitored daily for 2 days after the procedure, weekly for the first month, and then monthly. Laryngeal function was evaluated and cervical ultrasonography and thyroid scintigraphy were also performed. Monitoring continued for as long as 9 months after heat ablation if a cat became euthyroid or until an owner chose an alternative treatment because of recurrence of hyperthyroidism.

RESULTS

Serum TT4 and fT4 concentrations transiently decreased after all 14 heat ablation procedures (< or = reference range after 10 of 14 treatments) within 2 days after the procedure. Cats were euthyroid for 0 to 18 months (mean, 4 months). Hyperthyroidism recurred in all cats. Adverse effects included transient Horner's syndrome (2 cats) and laryngeal paralysis without clinical signs (1 cat).

CONCLUSIONS AND CLINICAL RELEVANCE

Percutaneous heat ablation as a treatment for hyperthyroidism in cats is effective transiently but not permanently.

Radioiodine therapy in patients with hyperthyroid disorder: standard versus dosimetric activity application

Due to its high success rate and non-invasive character, an increasing demand for radioiodine therapy can be seen. This study was conducted to determine whether standardized 131I activities can be used to facilitate management of patients with hyperthyroid disorder or whether a pre-therapeutic radioiodine test is advisable to determine an adequate therapeutic activity. The therapeutic uptake of 218 patients with benign thyroid disorders were determined and compared with 24 h and 48 h test uptake measurements as well as with calculated standard uptake values. Since there is a linear relationship between iodine uptake and delivered radiation dose, the effect of the different therapeutic approaches on the latter parameter was analysed. Special care was taken to assess possible differences between the various thyroid disorders. A mean deviation between pre-therapeutic test uptake and actual therapeutic uptake of 14.7% was observed in contrast to one of 29.1% when using disease specific standard values per millilitre of thyroid tissue. Furthermore, the proportion of patients with large deviations of more than 40% increased drastically when using standard uptake values (with radioiodine test, 4.1%; with standard values, 18.8%). In conclusion, the dosimetric approach with a pre-therapeutic radioiodine test proved to be the most accurate therapeutic procedure. Both the 24 h and 48 h test uptake measurements gave analogous results and yielded a correlation coefficient of 0.91 when compared with the therapeutic uptake. While it may be tempting to use standard activities to facilitate patient management, the findings of this study confirm that, for precise therapy planning, a pre-therapeutic radioiodine test is advised. Since no significant difference could be found between the 24 h and 48 h test uptake values, an early measurement 24 h after administration of the test activity is recommended.

Association of hyperfunctioning thyroid adenoma with thyroid cancer presenting as "trapping only" nodule at 99mTcO4- scintigraphy

Rarely may a non-hyperfunctioning thyroid nodule present as "hot" at Technetium-99m pertechnetate (99mTcO4-) and "cold" at radioiodine scintigraphy at late acquisitions. We report the case of a hyperthyroid female patient whose 99mTcO4- scintigraphy showed two "hot" nodules, whereas Iodide-131 (131I-) revealed a lack of indicator uptake by the larger, and intense uptake by the smaller nodule. The patient underwent surgery: histology demonstrated that the larger nodule, mismatched at pertechnetate vs iodine scintigraphy, was a papillary carcinoma. Our suggestion is to perform thyroid scintigraphy with radioiodine in hyperthyroid patients with more than one nodule concentrating pertechnetate, especially when an ultrasonographic pattern possibly suspect for malignancy is present.

Ectopic thyroid

Primary mediastinal ectopic goiters are very rare. We report a case in which an ectopic goiter with blood supply from the thoracic vessels necessitated a transternal approach for removal, resulting in a favorable outcome.

[Procedure guideline for radioiodine test (version 2)]

The version 2 of the procedure guideline for radioiodine test is an update of the guideline published in 1999. The following statements were added or modified: The procedure guideline discusses the pros and cons of a single measurement or of repeated measurements of the iodine-131 uptake and their optimal timing. Different formulas are described when one, two or three values of the radioiodine kinetic are available. The probe with a sodium iodide crystal, alternative or additionally the gamma-camera using the ROI-technique are instrumentations for the measurement of iodine-131 uptake. A possible source of error is an inappropriate measurement (sonography) of the target volume. The patients' preparation includes the withdrawal of antithyroid drugs 2-3 days before radioiodine administration. The patient has to avoid iodine-containing medication and the possibility of additives of iodide in vitamin- or electrolyte-supplementation has to be considered.

Cardiac oxidative metabolism, function, and metabolic performance in mild hyperthyroidism: a noninvasive study using positron emission tomography and magnetic resonance imaging

Using noninvasive imaging, we have previously demonstrated that myocardial efficiency is impaired in hypothyroidism and improves after establishing euthyroid conditions. Little is known about the effects of abnormally elevated thyroid hormone exposure on cardiac metabolic performance. We studied 10 patients without evidence of heart disease in mild hyperthyroidism, and after therapy under euthyroid conditions. Cardiac oxidative metabolism was quantified by positron emission tomography with [(11)C]acetate. Left ventricular geometry was determined by cine magnetic resonance imaging. Myocardial efficiency, defined by the relation between work and oxygen consumption, was estimated using the work metabolic index [WMI = stroke volume * systolic blood pressure * heart rate/(oxidative metabolism * ventricular mass)]. In hyperthyroidism, heart rate and cardiac output were expectedly higher. Peripheral vascular resistance was reduced. Differences of blood pressure, stroke volume, and ventricular mass were not observed. Oxidative metabolism was significantly higher, but WMI was not different from the euthyroid state. In summary, while improvement of efficiency through thyroid hormone substitution was observed previously in hypothyroidism, our data in mild hyperthyroidism suggest an increase of oxygen consumption, paralleled by an increase of work. Thus, moderately elevated thyroid hormone levels neither result in further increase nor in reduction of cardiac metabolic performance.

[Basedown disease, thyroid gland autonomy, nodular goiter. When is radiotherapy indicated?]

Treatment options for benign diseases of the thyroid include medication, radioiodine therapy and surgery. Patients with hyperthyroidism initially receive antithyroid drugs, with further treatment determined by the relapse risk. In the case of Graves' disease this is determined by a number of risk factors, including the volume of the thyroid gland or the presence of endocrinal ophthalmopathy. In such cases with a high relapse risk, radioiodine therapy is the recommended first-line treatment. Further indications--if surgery is not necessary--are autonomous goiter, recurrent (autonomous) goiter and latent hyperthyroidism. A single radioiodine treatment suffices to control the situation in more than 90% of the cases, and the goiter clearly diminishes in size. Radiation-induced malignancies or malformations have not been seen, but iodine treatment is contraindicated in pregnancy. In view of the short hospital stay of only four to five days, and the ready availability of treatment units, the authors consider radioiodine therapy a suitable first-line option in patients with Graves' hyperthyroidism.

[Comparison of the radioiodine thyroid uptake of diagnostic dose and therapeutic dose in patients with hyperthyroidism]

OBJECTIVE

To compare early kinetics of diagnostic dose 131I with that of therapeutic dose.

METHODS

Thyroid Uptake Ratio (TUO) measurements of diagnose method on SPECT in 108 patients after oral administration 131I.

RESULTS

The TUO of diagnostic dose was similar to that of therapeutic dose at 24 hours after the patients had take 131I (P > 0.05).

CONCLUSION

Radioiodine thyroid uptake of diagnostic dose is consistent with that of therapeutic dose at 24 hours after oral administration of 131I.

Subclinical hyperthyroidism in dementia and correlation of the metabolic index in FDG-PET

AIM

Thyroid hormone status and thyroid antibodies were evaluated in patients suffering from dementia for further study of an association of hyperthyroidism with AD and vascular dementia (VD), respectively.

PATIENTS

In 77 patients with dementia, and 42 controls, thyrotropin (TSH) and thyroid antibodies were correlated with the different types of dementia and the metabolic index (MI) based on imaging with F-18-2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET).

RESULTS

Twenty-two of all patients with dementia (29%) had borderline (TSH 0.3-0.5 mU/l) or decreased TSH levels (TSH < 0.3 mU/L). TSH values were significantly lower in patients suffering from AD (median: 1.1 mU/l) and VD (0.5 mU/l) than in the control group (1.5 mU/l) (p < 0.01). Decreased or borderline TSH levels were present in 52% of the patients with VD, but in only 10% of the controls, and in 23% of the patients with AD. Antibodies to thyroid peroxidase were positive in 16% of all patients with dementia. The MI in patients suffering from AD with borderline TSH levels was 0.81 (0.70, 0.94). In contrast, patients suffering from AD with normal TSH values showed a slightly higher MI of 0.84 (0.76, 0.89) (p = n.s.).

CONCLUSION

Decreased or borderline TSH values are associated with an increased probability of having dementia, especially VD.

[Interest of MIBI scintigraphy in the preoperative investigation of primary hyperthyroidism]

OBJECTIVE

The purpose of this study is to show the place of MIBI scintigraphy in the preoperative investigation of primary hyperthyroidism, and then to demonstrate the extent to which this test allows us to formulate new surgical strategies, thus reducing the need for neck exploration in favour of minimally invasive techniques.

MATERIALS AND METHODS

We have carried out a retrospective study related to 118 cases of primary hyperthyroidism. A MIBI scintigraphy has been applied on all the patients, so that we have been able to compare its results with the surgical and histological findings.

RESULTS

Our study shows a great accuracy of MIBI scintigraphy, with respect to the localization of parathyroid adenoma, which represents the major cause of primary hyperparathyroidism. Furthermore, these results prove the reliability of the new surgical strategies: unilateral neck exploration and minimally invasive surgery, when facing a single scintigraphic site.

CONCLUSION

As of now, MIBI scintigraphy must be part of preoperative investigation in cases of primary hyperparathyroidism, so that by limitating the surgical neck exploration, it allows us to decrease operative time and the risks, length and cost of the hospital stay.

[Subacute thyroiditis with cell destruction and temporary hyperthyroidism in Graves'disease--case report]

We present the case of a 60-year old woman with painful swelling of the thyroid gland and temporary thyrotoxicosis. 30 years ago she had experienced a period of hyperthyroidism because of Graves' disease. This time thyrotropin-receptor-antibodies were negative, Tc-99 m scan revealed decreased uptake in both lobes (this pattern normalised later on) and fine needle aspiration presented leucocyte infiltration of the thyroid. Three months later hypothyroidism was observed requiring treatment with levothyroxine. The development of subacute thyroiditis and Graves' disease in the same person is rare, autoimmune factors and a possible relationship are discussed.

Ovarian Ultrasound and Ovarian and Adrenal Hormones before and after Treatment for Hyperthyroidism

OBJECTIVE

To relate thyroid, steroid and pituitary hormones to ovarian ultrasonographic findings in hyperthyroid patients before and during treatment.

STUDY DESIGN

Ultrasonography of the ovaries and serum hormone determination by immunoassay were performed before and during thiamazole therapy in 18 women of fertile age treated for hyperthyroidism at the Danderyd Hospital from 1996 to 1998.

RESULTS

When hyperthyreotic, the patients had elevated serum levels of sex hormone-binding globulin (SHBG) and subnormal values of cortisol, free testosterone (fT) and dehydroepiandrosterone (DHEA). In the euthyreotic state following treatment, endocrine variables were normalized. Patients with a short duration of the disease had higher pretreatment levels of free thyroxine (fT4), SHBG and testosterone and lower corticosteroid binding globulin (CBG) and cortisol levels compared to patients with a long duration of the disease. The pretreatment ultrasonographic picture was abnormal in 16 of 18 patients. Of the 8 patients who were examined by ultrasonography after 3 months of treatment, all but 1 showed a normal picture. Samples from patients showing an abnormal ultrasonographic picture had significantly higher fT4 and lower free testosterone (fT) values than samples from patients with a normal ultrasonographic picture.

CONCLUSION

Ultrasonographic findings showing a multicystic/multifollicular picture, resembling polycystic ovaries (PCO), in hyperthyroidism may be related to direct effects of thyroid hormones on the ovaries and/or altered intraovarian androgen environment due to elevated SHBG levels. It is highly recommended to assess the thyroid status in patients with multicystic/multifollicular ovaries/PCO.

Thyroid ultrasound versus antithyroid peroxidase antibody determination: a cohort study of four hundred fifty-one subjects

Autoimmune thyroiditis is mirrored by a hypoechoic ultrasound pattern. We determined diagnostic precision of thyroid sonography compared to that of anti-thyroid peroxidase antibody (TPOAb) concentration. Ambulatory patients with unknown thyroid status (n = 451; 407 female, ages 44 +/- 16 years; 45 male, ages 50 +/- 14 years) excluding those with suspected hyperthyroidism or on drugs known to cause hypothyroidism were recruited consecutively. Subjects were recruited from a specialized thyroid outpatient unit with higher frequencies of thyroid disorders than in the general population. Before determination of thyroid function and TPOAb concentration thyroid volume (normal values: women < 12 mL, men < 14 mL) and echogenicity (grade 1 = normal: similar to submandibular gland, hyperechoic to neck muscles; grade 2: hypoechoic to submandibular gland, hyperechoic to neck muscles, grade 3: iso-/hypoechoic to neck muscles) were determined. Positive predictive value of grade 3 pattern for detection of autoimmune thyroiditis was 94% (with overt hypothyroidism) and 96% (with any degree of hypothyroidism), that of grade 2 or 3 85% and 87%, respectively. Negative predictive value of grade 1 pattern for detection of euthyroid TPOAb negative subjects was 91%. Goiter was present in 31% and 21% of TPOAb postive and negative subjects, respectively, while 11% and 15% had an atrophic thyroid gland (p = not significant [n.s.]). Given a high intraobserver and interobserver agreement abnormal thyroid ultrasound patterns were highly indicative of autoimmune thyroiditis and allowed the detection of thyroid dysfunction with 96% probability.

Influence of therapy with iodine-131 on thyroid tissue pattern in colour and power Doppler sonography

AIM

The aim of this study was to evaluate the influence of radioiodine therapy on sonographic thyroid patterns using power Doppler (PD) and colour Doppler (CD) sonography in hyperthyroid patients with autonomous nodules (AN) and Graves' disease (GD).

METHOD

B-mode, colour, and power Doppler sonography, (99m)Tc scintigraphy, and laboratory analyses (free thyronine fT(3), free thyroxine fT(4), thyroid stimulating hormone TSH) were performed in 55 patients (AN = 27, GD = 28) before and 6 months following therapy with (131)I radioiodine therapy (RIT).

RESULTS

In patients with an AN (but not in GD), a significant reduction in thyroid vascularization was subjectively noted following radioiodine therapy on both CD and PD ultrasound (Wilcoxon matched pairs, P < 0.05). The pre-therapeutic grade of hypervascularization in the periphery of autonomous nodules correlated closely with the laboratory parameters of hyperthyroidism. As expected, PD indicated a higher grade of vascularization when compared with CD due to its greater sensitivity to flow.

CONCLUSIONS

Radioiodine therapy led to a significant reduction in hypervascularization in patients with AN (but not in GD) corresponding to the normalization of serological values. Comparing CD and PD, PD detected a greater number of vessels. CD and PD are not able to replace scintigraphy and/or laboratory analyses in the management of patients with hyperthyroidism.

Quantitative thyroid scintigraphy as a predictor of serum thyroxin concentration in normal and hyperthyroid cats

Quantitative thyroid scintigraphy using pertechnetate was performed in 43 cats with various T4 concentrations and compared to eight normal control cats. Quantitative parameters included percentage dose uptake of the radioisotope by the thyroid, thyroid:salivary ratio and rate of thyroid uptake. All cats were anesthetized for the scan, and images were obtained using both low-energy all purpose (LEAP) and pinhole collimators. All quantitative parameters were significantly correlated to the serum T4 concentration, but the best correlation was obtained using the 20-minute thyroid:salivary ratio using only the most intense of the two thyroid lobes. The thyroid:salivary ratio was a good predictor of the metabolic status of the thyroid.

[Differentiated thyroid gland carcinoma in a scintigraphically hot thyroid nodule: diagnosis and interdisciplinary therapeutic management]

A hyperfunctioning differentiated thyroid carcinoma is a rare occurrence. Nevertheless, this diagnosis must be considered in a scintigraphically hot nodule if there is a clinical or sonographic suggestion of malignancy. The case of a 57-year old patient with hyperthyreosis and a scintigraphically hot thyroid nodule is presented. Further evaluation led to the diagnosis of a differentiated thyroid carcinoma with extensive lymph node and pulmonary metastases (pT2b, pN1b, pM1). The scintigraphically hot nodule corresponded to the primary tumor, whereas scintigraphic detection of the lymph node metastases was only possible postoperatively. Extensive resection of the lymph node metastases was achieved by the intraoperative application of a gamma probe (2nd operation). This allowed sufficient uptake of radioiodine in the pulmonary metastases for their detection and subsequent devitalisation by radioiodine therapy. Complete elimination of all tumour tissue was documented at a control follow-up after six months. Gamma probe-guided surgery may allow for additional removement of non-palpable lymph node metastases. In selected cases this may optimize the surgical results and thereby facilitate the subsequent radioiodine elimination of advanced differentiated thyroid carcinomas.

Dose selection for radioiodine therapy of borderline hyperthyroid patients with multifocal and disseminated autonomy on the basis of 99mTc-pertechnetate thyroid uptake

The aim of this study was to optimise radioiodine therapy of diffuse and nodular toxic goitre by calculation of the radiation dose delivered to the thyroid on the basis of the pretreatment technetium-99m pertechnetate thyroid uptake under thyrotropin suppression (TcTU(s)). The TcTU(s) value serves as a substitute for the non-suppressible iodine turnover and the functional autonomous mass. Marinelli's formula was used to calculate tissue absorbed doses of 150 Gy, 200 Gy, 250 Gy and 300 Gy to the thyroids of 438 patients with multifocal and disseminated autonomy. The mean age of patients was 70+/-9 years, and the mean thyroid volume was 54+/-26 ml. Two hundred and sixty-one of the patients had at least one documented previous episode of overt hyperthyroidism. Tissue absorbed doses were adapted to the pretreatment TcTU(s): 150 Gy for a TcTU(s) of 1.5%-2.49%, 200 Gy for a TcTU(s) of 2.5%-3.49%, 250 Gy for a TcTU(s) of 3.5%-4.49% and 300 Gy for a TcTU(s) of > or =4.5%. Normalisation of TcTU(s) and thyrotropin (TSH), thyroid volume reduction and frequency of hypothyroidism and recurrent hyperthyroidism were evaluated 1 year after a single radioiodine therapy. The presented dose strategy resulted in normalisation of TcTU(s) in 96% and an increase in TSH to the normal range in 92%. Recurrent hyperthyroidism was observed in only five patients. Thyroid volume decreased from 54+/-26 before treatment to 34+/-20 ml, a mean reduction of 37%. The frequency of hypothyroidism, at 0.9%, was encouragingly low. Dose selection in accordance with pretreatment TcTU(s) can be recommended for elimination of functional autonomous tissue with a single radioiodine therapy in patients of advanced age with enlarged thyroid glands and relevant autonomous masses who are at risk of developing iodine-induced hyperthyroidism.

[Computer analysis system for scintigraphic imaging of the thyroid in patients with hyperthyroidism treated with radioiodine]

Computerised system for analysis of radioiodine therapy efficiacy in hyperthyroid patients was presented. The system is based on comparative analysis of maximal emission distribution recorded in scintigrams performed before and after the treatment. It seems that the system after improvement of its software will be useful for clinical practice.

Differential diagnosis of hyperthyroidism: Doppler sonographic quantification of thyroid blood flow distinguishes between Graves' disease and diffuse toxic goiter

The aim of our study was to evaluate the usefulness of color duplex sonography to distinguish Graves' disease from diffuse toxic goiter. 24 patients with Graves' disease and 13 patients with diffuse toxic goiter underwent B-mode- and color duplex sonography of the thyroid gland. All patients had hyperthyroidism and elevated (99m)Tc-uptake. Spectral Doppler recordings were obtained at all thyroid arteries. Representative color flow maps of the thyroid gland were analyzed, calculating the percentage area of the thyroid gland, occupied by color pixels (color pixel density). The B-mode ultrasound pattern was subjectively assessed on a 4-point rating scale. In patients with Graves' disease the mean peak systolic velocity (PSV) (SD) was 110 (+/- 49) cm/s, the mean volume flow rate (VFR) was 123 ( +/- 67) ml/min and the mean color pixel density (CPD) was 33 (+/- 12) %. For patients with diffuse toxic goiter mean PSV (SD) was 43 ( +/- 9) cm/s (p < 0.001), mean VFR was 23 (+/- 10) ml/min (p < 0.001) and mean CPD was 9 (+/- 6) % (p = 0.007). CPD and spectral duplex recordings were positively correlated (CPD/PSV: rs = 0.77, CPD/VFR: rs = 0.75; p < 0.0001). No significant differences were observed concerning RI values. Sensitivity was 87% and specificity 92% for CPD and VFR and 87% and 100% for PSV. We conclude, that color duplex sonography can reliably distinguish diffuse toxic goiter from Graves' disease and therefore contributes significantly to the differential diagnosis of hyperthyroidism in diffuse thyroid disease.

Percutaneous ethanol injection of autonomous thyroid nodules with a volume larger than 40 ml: three years of follow-up

AIM

Autonomous thyroid nodules are conventionally treated by surgery or radioiodine. Percutaneous ethanol injection is a recognized alternative approach. An assessment of the long-term success and safety was conducted.

MATERIALS AND METHODS

Thirty-four patients (seven men and 27 women; age range: 32-80 years; mean: 56 +/- 13 years) with an autonomous thyroid nodule (ATN) > 40 ml (volume range 41-180 ml; mean: 63.6 +/- 34.5 ml) were treated with ultrasound-guided percutaneous ethanol injection (PEI). All patients were hyperthyroid with increased radionuclide uptake in the nodule at scintigraphy. Serial serum (free T3, free T4 and thyroid-stimulating hormone (TSH)) and ultrasound studies were performed at 3, 6, 12, 18, 24 and 36 months after the first PEI session. Scintigraphy was performed before treatment and 1 month after the serum TSH became detectable or alternatively after 6 months, even if the TSH was still undetectable.

RESULTS

Each patient had 1-11 sessions of PEI, with an injection of 3-14 ml of ethanol per session (total amount of ethanol per patient: 20-125 ml). Within 3 months from the end of the treatment, the recovery of extranodular uptake on isotope scan and the normalization of TSH levels were observed in 30/34 patients. A reduction (average: 62.9%) of nodule volume was recorded in all patients and only 4/34 patients were refractory to PEI. The responsiveness of ATN to PEI appeared to be dependent on the initial nodule volume (3/4 failures in patients had nodule volumes > 60 ml). Side-effects were always self-limiting. During follow-up (6-36 months) no recurrence was observed.

CONCLUSION

In conclusion, the treatment of ATN > 40 ml with PEI would appear to be a valid alternative approach to traditional methods of treatment. It is safe, well tolerated and inexpensive. Its acceptability when compared with surgery and radiodioine has still to be assessed.

The effect of methimazole on thyroid uptake of pertechnetate and radioiodine in normal cats

Many hyperthyroid cats referred for thyroid imaging and 131I therapy are concurrently or recently receiving antithyroid medications. The effect of the antithyroid drug, methimazole, on thyroid uptake of 99mTcO4 and 123I was evaluated in 8 normal cats. Quantitative analysis was used to determine the normal percent dose uptake of 99mTcO4 and 123I, the change in thyroid:salivary ratios (T:S) of 99-TcO4 over time, and the duration of the methimazole effect on thyroid uptake of 123I. Methimazole was administered to 5 cats for 3 weeks in which a hypothyroid state was obtained; 3 cats served as non-treatment controls. 99mTcO4 and 8 and 24 hour 123I imaging was repeated after 3 weeks of methimazole therapy (time of maximum T4 suppression). Methimazole was then discontinued and 123I images and serum T4 concentrations were repeated at 1, 4, 9, 15, and 24 days post withdrawal. The percent dose uptake of 99mTcO4 increased throughout the acquisition period with maximum uptake occurring 4 hour post injection. The baseline 20 min. T:S ratio for controls and treatment cats were 0.79 +/- 0.08 and 0.81 +/- 0.05 respectively; with a peak value of 1.29 +/- 0.23 and 1.31 +/- 0.18 at 4 hours. The baseline T:S ratios were not significantly different from 20 minutes to 2 hours, however they were significantly elevated at 4 hours post injection. Baseline, 8 and 24 hour percent dose uptake of 123I were 2.1 +/- 0.42% and 7.04 +/- 1.24%, respectively. There was a significant increase in the T:S ratio in the treatment group at all time points. The 8 hour percent dose uptake of 123I at 1, 4, and 9 days post methimazole withdrawal were significantly increased and peaked at 4 days. The 24 hour uptake was significantly increased at 4 and 9 days, with peak uptake at 9 days post-methimazole withdrawal. The 123I percent dose uptake decreased to baseline values by day 15 post withdrawal. Radioiodine uptake is not inhibited by methimazole treatment in normal cats, and is significantly enhanced after recent withdrawal. This finding is supportive of a "short term rebund effect" with maximal enhanced uptake between 4 and 9 days after discontinuing antithyroid drugs. The increased uptake of 99mTcO4 may also affect the interpretation of 99mTcO4 thyroid scintigraphy for 2-3 weeks.

Distinction between autoimmune and non-autoimmune hyperthyroidism by determination of TSH-receptor antibodies in patients with the initial diagnosis of toxic multinodular goiter

Distinguishing Graves' disease (GD) from a toxic multinodular goiter (TMG) subgroup with a diffuse but uneven Tc-distribution depends on the diagnostic power of the TSH-receptor antibody (TRAb) determination. Bioassays using CHO cell lines expressing the hTSH-receptor or a new TBII assay, which uses the hTSH-receptor as an antigen (DYNOTEST TRAK human, Brahms, Germany), showed a higher sensitivity for the detection of TRAbs in patients with GD than assays using solubilized porcine epithelial cell membranes. The aim of this study was to investigate whether the new Dynotest TRAK human assay has an increased sensitivity to distinguish GD from non-autoimmune hyperthyroidism. Therefore, we examined 21 consecutive patients with the initial diagnosis of TMG for thyroid-stimulating antibodies (TSAbs, JP26 cell assay) and TBII with the new highly sensitive Dynotest TRAK human (Brahms, Germany). The initial diagnosis of TMG was based on suppressed TSH and a patchy Tc-uptake of more than 1 % and less than 7 % or TSH of more than 0.3 mIE/l with a patchy Tc-uptake of more than 1.5 % and less than 7 % and negative TBII values in a displacement assay using solubilized porcine epithelial cell membranes (TRAK, Brahms, Germany). 11 sera from these 21 patients showed TSAb activity. Furthermore, 10 of these 11 TSAb-positive sera were also positive in the Dynotest TRAK human assay, whereas one serum sample was borderline positive. TSAb activity and inhibition of (125)I-bTSH binding in the Dynotest TRAK human assay correlated well (r = 0.7). Therefore, 11 of the 21 investigated patients initially classified as TMG actually had GD, which was undetectable using the porcine TBII assay. In conclusion, TSAbs or TRAbs detected with the Dynotest TRAK human have the highest diagnostic power to differentiate GD from TMG. Because of the less cumbersome assay technique, the Dynotest TRAK human measurements should be obtained for all patients with non-typical TMG to differentiate GD from non-autoimmune hyperthyroidism in order to select the appropriate therapy for these patients.

Thyroid ultrasound

Evaluation of the thyroid gland can be performed by several imaging techniques. Although ultrasound (US) lacks specificity for tissue diagnosis and can rarely distinguish benign from malignant disease, it can distinguish solid nodules from simple and complex cysts. It allows accurate estimation of thyroid size, gives a rough estimate of tissue density (echogenicity), shows vascular flow and velocity (color-flow Doppler), can identify regional lymphadenopathy, and aids in the accurate placing of needles for diagnostic or therapeutic purposes. In addition, it is widely available, relatively rapid and cheap, visualizes the whole anterior neck, and does not involve ionizing irradiation. This article aims at clarifying the role of US in clinical thyroidology by pointing to areas where the technology can aid in clinical decision making. It is argued that more clinician endocrinologists should master and use this technology for diagnostic and therapeutic purposes.

Role of radionuclide imaging in hyperthyroid patients with no clinical suspicion of nodules

The purpose of the study was to assess the role of radionuclide imaging of hyperthyroid patients with no suspicion of nodules. (99)Tc(m) radionuclide scans performed on all 190 patients referred over a 2-year period with symptoms and thyroid function tests compatible with thyrotoxicosis were retrospectively reviewed. 73% of patients were referred by a hospital clinician and 27% were referred direct from the general practitioner. Referral letters and, where applicable, the clinical notes were reviewed and patients with suspected thyroid nodules were excluded. The results of (99)Tc(m) thyroid scans of the 190 patients (age range 23-93 years, mean 48 years) were reviewed. 152 (80%) patients had Graves' disease, 10 (5.3%) had Graves' disease with nodules, 6 (3.2%) had Graves' disease with non-functioning nodules, 5 (2.6%) had viral thyroiditis, 5 (2.6%) had autonomously functioning nodules and 12 (6.3%) were normal studies. Therefore, 20% of patients had a diagnosis other than solely Graves' disease. These diagnoses are important with respect to clinical management. In conclusion, routine radionuclide imaging is worthwhile, as a significant proportion of patients with clinical "Graves' disease" in this study would have received incorrect treatment without the result of this scan.

Radioiodine uptake and thyroid scintiscanning

This article reviews the technical aspects and clinical applications of the radioactive iodine uptake test and thyroid scintiscanning. The choice of radionuclide for the tests is discussed. The main uses of the radioactive iodine uptake test are to identify the cause of hyperthyroidism and to aid in the selection of the I-131 dose in the treatment of hyperthyroidism. Factors other than thyroid diseases that alter uptake results are identified. Thyroid scintiscanning is used in the identification of normal and ectopic thyroid tissue, in the diagnosis of the cause of a patient's hyperthyroidism, and as part of the evaluation of selected patients with thyroid nodules.

[Pulmonary hypertension associated with refractory hyperthyroidism: a case report]

A 25-year-old woman was admitted to our hospital with goiter. The diagnosis was Grave's disease. Diagnostic transthoracic echocardiography revealed a hyperdynamic stage of the heart with right ventricular dilation. Doppler echocardiography showed mild to moderate tricuspid regurgitation and elevated systolic right ventricular pressure. Right heart catheterization revealed high cardiac output (9.49 l/min) and pulmonary hypertension (57 mmHg) with increased pulmonary vascular resistance and total pulmonary resistance. No intracardiac shunts were detected. Since neither thiomazole nor propylthiouracil was effective and both caused side effects, she underwent subtotal thyroidectomy. After the surgery, pulmonary hypertension improved and cardiac output normalized, but without normalization of pulmonary vascular resistance and total pulmonary resistance. Reversible pulmonary hypertension may occur in patients with hyperthyroidism. Increased pulmonary blood flow and sustained high pulmonary artery resistance were suspected as the causes of pulmonary hypertension. In addition, pulmonary endothelial dysfunction as a result of sustained increased pulmonary blood flow could be another cause of pulmonary hypertension.

Thyroid function, thyroid immunoglobulin status, and urinary iodine excretion after enteral contrast-agent administration by endoscopic retrograde cholangiopancreatography

BACKGROUND AND STUDY AIMS

The aim of this study was to examine the occurrence of clinically relevant changes in thyroid function after enteral administration of contrast agent by endoscopic retrograde cholangiopancreatography (ERCP).

PATIENTS AND METHODS

In this study 70 patients without a history of thyroid disease who had not recently undergone thyroid-specific or thyroid-influencing therapy were examined. Patients were examined on two or three occasions using a standardized questionnaire regarding symptoms of hypothyroidism and hyperthyroidism. The parameters of thyroid function (TT3, TT4, FT4, thyroid-stimulating hormone (TSH)) and urinary iodine excretion were measured on day 0 and on day 21 post-ERCP, and in 23 patients additionally on day 42 post-ERCP. Based on ultrasonographic results, four groups differing in thyroid morphology were distinguished.

RESULTS

The data show that an average amount of only 4.7 g of enterally applied iodine is associated with a lasting decrease of TSH, especially in patients with enlarged organs with nodular transformation. As far as TT3 is concerned, there was a significant increase in all patient groups; regarding FT4 we only observed a marked increase in the group with enlarged, nodular thyroid glands. There was a notable increase in urinary iodine excretion on day 21, and a further increase on day 42 post-ERCP. Clinical symptoms of hyperthyroidism did not occur.

CONCLUSIONS

We conclude that before administration of iodine-containing contrast agent for ERCP in patients without a history of thyroid disease, thyroid ultrasonographic examination, rather than TSH measurements, should be performed, in order to identify patients already at risk for hyperthyroidism before diagnostic enteral contrast-medium application.

Radioiodine and percutaneous ethanol injection in the treatment of large toxic thyroid nodule: a long-term study

Surgery is generally recommended for large thyroid toxic nodules (TTNs). When surgery is not applicable, both radioactive iodine (RAI) and percutaneous ethanol injection (PEI) are alternative treatments. In this retrospective study, the long-term efficacy of nonsurgical treatments was evaluated in 43 patients with TTN, selected on the basis of presence of hyperthyroidism and a fairly large nodule (3- and 4-cm in diameter) completely inhibiting controlateral lobe captation during scintigraphy. Twenty-one patients were treated by RAI (administered dose 670+/-160 MBq; range 555-925) and twenty-two were treated by PEI (6+/-1 sessions; range 5-9). FT4, FT3, thyrotropin (TSH), and nodule volume were assessed before and at fixed intervals after treatment. Median follow-up was 36 months (range, 12-84). Compared to baseline values, with both therapies, serum FT4, FT3, and nodule volume were decreased (p < 0.01) and serum TSH was increased (p < 0.01), after 3 months and during the entire follow-up. Nodule volume reduction percentage was 66.8+/-22.0 and 78.4+/-18.0, in the RAI- and PEI-treated groups, respectively. At the end of follow-up, 34 patients were euthyroid (16 RAI- and 18 PEI-treated). Four RAI-treated patients (19%) showed slightly high TSH levels (4.2-5.3 mU/L), whereas three PEI-treated patients (13.6%) still had suppressed TSH levels, although being clinically asymptomatic. One RAI-treated patient (4.8%) showed overt hypothyroidism during the follow-up period and was then treated with L-thyroxin. One patient (4.6%), who was initially cured by PEI, became newly hyperthyroid during the follow-up period. Both treatments were well-tolerated. In conclusion, both of these nonsurgical treatments are effective and may be chosen also for relatively large TTNs. Specifically, RAI seems to be more effective for treating hyperthyroidism but has minimal sequelae of subclinical or clinical hypothyroidism, while, after PEI treatment the possibility of stable subclinical hyperthyroidism or hyperthyroidism relapse should be taken into account.

Treatment of a thyrotropinoma with octreotide-LAR in a patient with multiple endocrine neoplasia-1

OBJECTIVE

To note that a thyrotropin (TSH)-secreting macroadenoma may be part of the multiple endocrine neoplasia-1 (MEN-1) syndrome and to report the use of octreotide-LAR (OCT-LAR) to treat a TSH-secreting macroadenoma in a patient with MEN-1 with previous surgery for hyperparathyroidism and gastrinoma.

METHODS

We present a patient with a TSH-secreting pituitary macroadenoma and report the results of her endocrine, genetic, radiologic, and nuclear medicine testing and her response to treatment with octreotide (OCT), octreotide-LAR, and estrogen.

RESULTS

This patient's TSH-induced hyperthyroidism responded to octreotide for 5 months and octreotide-LAR for more than 11 months. Her hypercalcemia normalized while she was taking estrogen. Her genetic testing is reported to show a genetic defect that is typical of patients with MEN-1.

CONCLUSION

This report describes: (1) The use of octreotide-LAR to treat both a TSH-secreting pituitary tumor and a gastrinoma over 12 months; (2) the importance of including these tumors into the MEN-1 syndrome with its attendant implications; and (3) a genetic defect, typical of patients with MEN-1, associated with this tumor.

Association of the vitamin D receptor genotype BB with low bone density in hyperthyroidism

Bone mineral density (BMD) is modulated by genetic and environmental factors or certain diseases. In several conditions such as low calcium intake, an influence of vitamin D receptor (VDR) polymorphisms on BMD has been suggested. In the present study, we investigated the relationship of Bsm I and Fok I polymorphisms of the VDR gene and BMD in patients with hyperthyroidism, a disease that often results in low BMD. Bsm I and Fok I genotypes were determined in 76 postmenopausal hyperthyroid patients and 62 healthy postmenopausal women as controls. Patients and controls were matched for age, time since menopause, and lifestyle factors and were free of estrogen medication. BMD evaluation included axial dual X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (PQCT). Low BMD was defined as -2.5 STD below the young adult mean value. Biochemical parameters investigated were thyroid hormones, osteocalcin, and 25-(OH)-vitamin D3 as well as routine laboratory data. Low BMD was found in 61% of hyperthyroid patients and in only 23% of euthyroid controls. In the group of hyperthyroid patients with low bone density, the BB genotype (VDR Bsm I polymorphisms) was significantly more frequent (39%) than in controls (13%; p = 0.003) and hyperthyroid patients with normal BMD (6%; p = 0.013). The odds ratio (OR) for low BMD in patients with BB genotype was 5.7 (95% CI, 1.7-19.1; p < 0.005) as compared with the Bb and bb genotypes and 5.5 (95% CI, 2.3-13.2; p < 0.0001) for hyperthyroidism alone. The cumulative risk for low BMD in patients with hyperthyroidism and BB genotype was 31.4 (95% CI, 3.9-256; p < 0.0003). VDR Fok I genotypes showed no significant relationship with BMD or other general or bone-specific parameters. Thus, hyperthyroidism and the genetic background of a BB genotype may promote synergistically the development of low BMD in hyperthyroid patients. Screening for the BB genotype in these patients therefore could help to identify those with particularly high risk for the development of low BMD and allow early treatment.

Struma ovarii with hyperthyroidism

A case of hyperthyroid disease after total thyroidectomy is reported. An initial scintigraph with Tc-99m sodium pertechnetate confirmed the absence of uptake in the neck. The view of the pelvis revealed a rounded area of increased uptake on the left, near the sacroiliac joint (results of bone scintigraphy were negative). A wholebody scan with iodine-131 confirmed a struma ovarii that was bilateral, which occurs in 5% to 10% of patients with this condition.

Color Doppler measurement of blood flow in the inferior thyroid artery in patients with autoimmune thyroid diseases

PURPOSE

The aim of the study is to find out whether the measurement of peak systolic velocity in the inferior thyroid artery (ITA) is a valuable parameter to differentiate autoimmune thyroid diseases (hyper-, normo- or hypofunctional) and to evaluate the efficacy of medical treatment.

MATERIAL AND METHODS

The ITA of 31 patients (eight with Graves' disease, 23 with subclinical hypothyroidism) was examined with color Doppler and pulsed Doppler. The final diagnosis was obtained by cytology and by hormonal and antibodies assays. The patients were monitorized by ultrasound for a period of 8 months.

RESULTS

In all the patients with Graves' disease the peak systolic velocity was always over 150 cm/s, while in other autoimmune thyroiditis the peak systolic velocity was within the normal range, and never exceeding 65 cm/s. In the first group, the measurement taken in the ITA showed also the efficacy of the pharmacological treatment earlier and more reliably than the color Doppler pattern obtained in the parenchyma.

CONCLUSIONS

The color Doppler measurement of the ITA seems to be a promising technique with low-cost and easy approach. In our experience, the color Doppler of the ITA could have a clinical role in the differential diagnosis of diffuse thyroid diseases and in the follow-up of the Graves' disease during medical treatment.

Comparison of 99mTc-methoxyisobutyl isonitrile and 201T1 scintigraphy in visualization of suppressed thyroid tissue

Both (201)TI and (99m)Tc-methoxyisobutyl isonitrile (MIBI) have been used in the visualization of suppressed thyroid tissue in patients with autonomously functioning thyroid nodules (AFTNs). It has been suggested that thyroid-stimulating hormone (TSH) control is not a major determinant of both tracers. However, the mechanism of thyroid uptake of these agents is controversial. In this study, we compared (201)TI and MIBI in the visualization of suppressed thyroid tissue in patients with a solitary toxic AFTN.

METHODS

Thirty-two patients (13 triiodothyronine [T3] and 19 T3 + levorotatory thyroxine [T4] hyperthyroid patients) with toxic AFTNs visualized on (99m)Tc-pertechnetate scanning were included in the study. All patients underwent MIBI and (201)TI thyroid scintigraphy within a 3-d interval. The scintigrams were analyzed both visually and semiquantitatively. For the semiquantitative analysis, regions of interest (ROIs) were generated over the nodule (N) and contralateral normal lobe (E), and the mean counts in each ROI were calculated.

RESULTS

The N/E uptakes (mean +/- SD) for pertechnetate, MIBI, and (201)TI were 11.37 +/- 4.53, 4.76 +/- 1.38, and 1.63 +/- 0.15, respectively, in T3 + T4 hyperthyroid patients and 9.46 +/- 3.64, 2.73 +/- 0.63, and 1.57 +/- 0.23, respectively, in T3 hyperthyroid patients. Our results showed that (201)TI uptake of suppressed thyroid tissue compared with AFTN was more prominent and significantly higher than that of MIBI for both groups of patients (P = 1.08E-05 for T3 and 6.15E-09 for T3 + T4 hyperthyroidism). There was no significant difference for either pertechnetate or (201)TI (P > 0.05) when the N/E uptakes of both groups of patients were compared. However, the N/E uptake of MIBI in T3 + T4 hyperthyroid patients was significantly higher than that in T3 hyperthyroid patients (P = 6.69E-06).

CONCLUSION

Clear visualization of suppressed thyroid tissue with both (201)TI and MIBI in patients with low serum concentrations of TSH suggests that TSH is not a major factor in the thyroid uptake of either agent. (201)TI is superior to MIBI in the visualization of suppressed thyroid tissue in patients with a toxic thyroid nodule. An increased rate of metabolism in the follicular cells of AFTNs in T3 + T4 hyperthyroid patients compared with that in T3 hyperthyroid patients might be responsible for the higher N/E for MIBI compared with that for (201)TI.