[Modern diagnostic approach to autoimmune thyroiditis]

High-resolution ultrasonography of the thyroid gland is the major primarytechnical diagnostic procedure in suspected autoimmune thyroiditis (AIT). A diffusely echo-poor thyroid is proof of the presence of AIT. Duplex sonography provides further information about the activity of the disease, and is of differential diagnostic importance for distinguishing postpartum thyroiditis from AIT, or for the investigation of an infiltrating carcinoma. Today, antibody determination serves merely to confirm the diagnosis, with TPO antibodies being the most specific for AIT. The TG antibodies may also be nonspecifically elevated in subacute thyroiditis (de Quervain) or irradiation or radioiodine treatment. For an evaluation of thyroid gland function in AIT, determination of basal TSH is needed.

Incidence of iodine deficiency in patients presenting with goitre--discrepancy between clinical and ultrasonographic evaluation of the thyroid: comparison of patients with and without autoimmune thyroiditis--clinical, hormonal and urinary iodine excretion studies

In endemic areas iodine deficiency, and in iodine sufficient regions autoimmune thyroiditis, is the first aetiological factor for goitre. The aims of this study were to determine the incidence of iodine deficiency and autoimmune thyroiditis in patients presenting with goitre, to compare clinical and ultrasonographic assessment of thyroid size and to investigate the relationship between iodine and autoimmune thyroiditis. Patients diagnosed with goitre clinically (n = 204) were evaluated by their anthropometric measurements, ultrasonographic examination of the thyroid gland, thyroid function and TRH stimulation tests, thyroid autoantibodies and morning urinary iodine measurements. Thyroid volumes were evaluated according to three different reference criteria. Incidences of iodine deficiency and autoimmune thyroiditis were 54% and 17%. The incidences of iodine deficiency and excess were not significantly different in the autoimmune group (n = 35) compared to the non-autoimmune group (n = 169). In the autoimmune group, urinary iodine concentration correlated positively with serum thyroid hormones (FT3 r = 0.42, TT3 r = 0.38, TT4 r = 0.34) and negatively with serum TSH levels (r = 0.45). There were discrepancies between clinical and ultrasonographic evaluation of goitre, and between different reference criteria. This study revealed that iodine deficiency is still the first aetiological factor for goitre in our region and failed to show a relationship between iodine intake and autoimmune thyroid disease.

Measurement of thyroid blood flow area is useful for diagnosing the cause of thyrotoxicosis

We have utilized color Doppler ultrasonography (CDU) to evaluate the thyroid blood flow area (TBFA) quantitatively, and we propose criteria to differentiate Graves' disease (GD) and destruction-induced thyrotoxicosis (DT) in patients with thyrotoxicosis. We studied 32 patients with diffuse toxic goiter, 21 with GD in the euthyroid state, 12 with chronic thyroiditis in the euthyroid state, and 31 normal individuals. TBFA was calculated as (thyroid blood flow area/thyroid area) x 100%. CDU showed high sensitivity (84%) and specificity (90%) in distinguishing GD from DT when TBFA was between 7.7% and 8.8%. Using CDU to diagnose GD in cases with TBFA >or=8% or positive serum anti-thyrotropin receptor antibody (TRAb), the sensitivity was 95% and the specificity was 90%, which are similar results to those obtained when GD was diagnosed by radioactive iodine uptake (sensitivity 100%, specificity 90%). Therefore, CDU is a more useful and economical method of distinguishing GD patients with TBFA of 8% or above from DT than measurement of TRAb or radioactive iodine uptake.

Putative association between anti-Borrelia IgG and autoimmune thyroid disease?

An association between borreliosis and autoimmune thyroid disease (AITD) has previously been discussed. We undertook the present analyses to explore associations between anti-Borrelia immunoglobulin G (IgG) and AITD using data from the population-based Study of Health in Pomerania (SHIP), which was conducted in a region with endemic Borreliosis. Data of 4,256 persons were available for the present analyses. IgG antibodies to Borrelia were determined by enzyme-linked immunosorbent assay (ELISA). AITD was defined as the combined presence of a hypoechogenic thyroid pattern in thyroid ultrasound and positive anti-thyroperoxidase levels. An association between anti-Borrelia IgG and AITD was neither present in bivariate nor in multivariate statistical analyses. This result was not affected by using different definitions of the exposure and the end points. There is no association between the exposure to Borrelia as defined by anti-Borrelia IgG and the risk of AITD. It seems unlikely that Borrelia species represent a relevant causal factor for AITD.

Effects of prophylactic thyroid hormone replacement in euthyroid Hashimoto's thyroiditis

Hashimoto's thyroiditis is the most frequent autoimmune thyroid disease. L-thyroxine therapy can reduce the incidence and alleviate the symptoms of this disease. The aim of this study was to evaluate the effects of prophylactic L-thyroxine treatment on clinical and laboratory findings of patients who were euthyroid at the time of diagnosis. Thirty-three patients who had diagnosis of euthyroid Hashimoto's thyroiditis were randomized to two groups, one group received prophylactic L-thyroxine treatment and the other was followed-up without treatment. Initial thyroid function tests, autoantibodies, ultrasonography, fine needle aspiration biopsy and peripheral blood lymphocyte subsets were similar in the two study groups. After 15 months of L-thyroxine treatment, there was a significant increase in free T4 and a significant decrease in TSH and anti-thyroglobulin antibody anti-thyroid peroxidase antibody levels. CD8+ cell counts increased in both groups, CD4/CD8 levels decreased significantly because of the increase in CD8+ cell count levels. Though there was no change in cytological findings, ultrasonography showed a decrease in thyroid volume in L-thyroxine receiving patients whereas an increase was detected in patients who were followed without treatment. In conclusion, prophylactic thyroid hormone therapy can be used in patients with Hashimoto's thyroiditis even if they are euthyroid.

[Prognostic value of color Doppler ultrasonography of the thyroid gland in autoimmune thyroiditis]

91 patients with chronic autoimmune thyroiditis have been examined. The obtained results showed considerable increase in resistance index in patients with hypothyroidism. It may be used as a prognostic criterion of the development of hypothyroidism.

[Color Doppler ultrasonography of the thyroid gland in diagnostics of autoimmune thyroiditis]

Diagnostics of thyroid gland pathology becomes more efficient with combined use of ultrasound and Doppler Ultrasonography. The article presents Color Doppler Ultrasonography data of 91 patients with hypertrophic and atrophic form of autoimmune thyroiditis. The obtained results showed considerable increase in resistive index in patients with chronic autoimmune thyroiditis and consequently the index can be used as diagnostic criterion of chronic autoimmune thyroiditis.

[Acquired childhood and juvenile subclinical hypothyroidism with or without goitre]

OBJECTIVE

Primary acquired childhood and juvenile hypothyroidism is mainly due to chronic thyroiditis or to the after effects of cervical radiotherapy for cancer. In the presence of clinically evocative signs, with a palpable goitre or firm thyroid, hypothyroidism is searched for. However, cases of childhood and juvenile hypothyroidism without goitre have been described.

METHOD

We retrospectively studied childhood and juvenile sub-clinical hypothyroidism in those in whom antithyroid antibodies had been searched for and thyroid ultrasonographic examination had been performed.

RESULTS

In this age group, we studied 34 cases of subclinical hypothyroidism (plasma TSH: 3.6-20 microIU/ml, normal free thyroxin level). In a first group (17 girls/1 boy, mean age: 14.4 years), 50% of patients had an abnormal palpable thyroid and 100% have auto-immunity markers. In the other group (7 girls/9 boys, mean age: 12.0 years), there was no goitre and no auto-immunity marker had been found. The clinical signs that prompted consultation were identical in the two groups and, if no goitre existed, measurement of TSH levels established the diagnosis of the onset of hypothyroidism.

DISCUSSION

It seems that second group patients constituted an unusual entity: predominance of boys, thyroid usually small and lack of auto-immunity markers.

99mTc-sestamibi thyroid uptake in euthyroid individuals and in patients with autoimmune thyroid disease

PURPOSE

We investigated the biokinetics of (99m)Tc-sestamibi in the thyroid of euthyroid volunteers (EVs) and in patients with autoimmune thyroid diseases and determined the best time interval between (99m)Tc-sestamibi injection and calculation of uptake.

METHODS

Forty EVs, 30 patients with Graves' disease (GD), 15 patients with atrophic Hashimoto's thyroiditis (AHT) and 15 patients with hypertrophic Hashimoto's thyroiditis (HHT) underwent (99m)Tc-sestamibi thyroid scintigraphy. Dynamic images were acquired for 20 min, and static images were obtained 20 min, 60 min and 120 min post injection. Five-, 20-, 60- and 120-min uptake, time to maximal uptake (T(max)) and T(1/2) of tracer clearance were calculated. Thyroid hormones and antibodies were measured. (99m)Tc-pertechnetate uptake was investigated in GD patients.

RESULTS

T(max) was approximately 5 min in all four groups. The mean T(1/2) value for EVs was similar to the GD value and lower than the HHT and AHT values. The mean (+/-SD) 5-min uptake was 0.13% (+/-0.05%) for EVs. The 5-min uptake in GD was higher than that in EVs(P<0.001) and correlated with free thyroxine (r=0.54) and with (99m)Tc-pertechnetate uptake (r=0.68). Uptake in HHT was higher than that in AHT (P=0.0003) and EVs (P=0.002). Uptake in AHT was lower than uptake in EVs (P=0.0001).

CONCLUSION

Five minutes is the optimal time interval between (99m)Tc-sestamibi injection and calculation of thyroid uptake. Five-minute uptake differentiates euthyroid individuals from GD patients. There is a high correlation between (99m)Tc-sestamibi and (99m)Tc-pertechnetate uptake in GD. The reduced (99m)Tc-sestamibi uptake in AHT patients is probably due to glandular destruction and fibrosis. Inflammatory infiltrate and high mitochondrial density in thyrocytes possibly explain the increased uptake in GD and HHT.

Serum levels of antibodies to thyroid peroxidase correlate with quantitative descriptors of thyroid ultrasound images in patients with breast cancer

The aim of the study was to compare the structural changes in ultrasound image of the thyroid tissue in 12 women with breast cancer (BC) and 8 women with colorectal cancer (CC). MATLAB software was used to analyse the digitised images. As quantitative descriptors of thyroid ultrasound images (QDTI) were used raw grey scale values of individual image pixels (RAW) and the optimal one-dimensional discriminative texture features (F2, F6, F7). The possible relations between QDTI and thyroid laboratory parameters were tested. In the BC group serum levels of antibodies to thyroid peroxidase negatively correlated with feature RAW (multiple regression, beta coefficient -0.75, p=0.004) and positively with feature F2 (multiple regression, beta coefficient 1.44, p=0.04). In the BC group RAW negatively correlated with serum levels of tumour marker CA 15-3 (Pearson's correlation coefficient, r=-0.714, p=0.00917). No such correlations were found in CC group. The correlations between QDTI and serum levels of antibodies to thyroid peroxidase in patients with BC show that the positivity of antibodies to thyroid peroxidase is probably accompanied with structural changes in the thyroid tissue.

Quantitative thyroid scintigraphy for the differentiation of Graves' disease and hyperthyroid autoimmune thyroiditis

AIM

The TCTUs (global (99m)Tc-pertechnetate thyroid uptake under suppression) can be used as an estimate of the iodine clearance of non-TSH regulated tissue. High TCTUs levels are characteristic for Graves' disease (GD). Decreased uptake has been described in autoimmune thyroiditis (AIT). However, systematically investigated data in a larger series of AIT-patients with subclinical or overt hyperthyroidism are not published so far. The purpose of this study is the evaluation of the TCTUs in the differentiation between AIT and GD in patients with hyperthyroidism.

METHODS

We determined the TCTUs in 59 patients with untreated hyperthyroid GD and in 51 patients with AIT who had subclinical or manifest hyperthyroidism without medication. Patients with GD were characterized by the presence of hyperthyroidism, decreased echogenicity of the thyroid, elevation of TSH-receptor autoantibodies (TRAb). AIT was defined by a decreased echogenicity of the thyroid, absence of elevated TSH-receptor autoantibodies (TRAb), autoantibodies against the thyroid peroxidase (anti-TPO) and spontaneous remission or development of subclinical hypothyroidism within 3 months.

RESULTS

Thyroid volumes of patients with AIT were significantly lower than those of patients with GD (p <0.05). TRAb levels were significantly higher in GD-patients (median: 19.5 U/ml; range: 15.3-35 U/ml) than in AIT-patients (median: 1.3 U/ml; range: 0-4.1 U/ml). 73% (38/59) of patients with GD had elevated anti-TPO levels. In these patients anti-TPO levels (median: 768 U/l; range: 83-6397 U/l) were not significantly different from anti-TPO levels of patients with AIT (median: 834 U/l; range: 107-8675 U/l; p = 0.17). TCTUs values of patients with AIT were significantly lower (p <0.05; median: 0.9%; range: 0.1-3.2%) than those of patients with GD (median: 5.7%; range: 1.9-28.3%).

CONCLUSION

In our patients quantitative thyroid scintigraphy with (99m)TcO(4)(-) offered rapid and reliable differentiation between hyperthyroid GD and AIT.

Small hyperechogenic nodules in thyroiditis: usefulness of cytological characterization

Small hyperechogenic nodules occurring in thyroiditis frequently raise the question of their nature requiring additional evaluation. Given the scarcity of the studies addressing this issue, we have investigated whether cytopathological analysis of fine needle aspirates (FNA) of these lesions may be of diagnostic relevance. In this preliminary study, we submitted to cytopathological analysis 10 nodular lesions as well as the normal counter-lateral tissue. In none but one of the cases analyzed, the cytopathology was able to detect differences between the hyperechogenic models and the hypoechogenic parenchyma suggesting that these lesions bear no-clinical relevance. Therefore, FNA of these nodules is not advisable and should be limited to those with defined at risk clinical features.

Thyroid autoantibodies and their clinical relevance in young adults with type 1 diabetes during the first 12 yr after diabetes onset

In order to obtain prospective data on occurrence of thyroid autoantibodies [against thyroid peroxidase (antiTPO) and against thyroglobulin (antiTgl)] and their clinical relevance, we followed up on 109 young adults with Type 1 diabetes for 12 yr after diabetes onset. The patients were divided into subgroup I [positivity of both thyroid autoantibodies (T-Ab); 25%, women predominantly], subgroup II (isolated antiTPO positivity only, 26%, men and women equally) and subgroup III (thyroid autoimmunity not present, 49%, men mainly). Cumulative incidence of T-Ab during the 12 yr of follow-up was 51% with predominance of women over men (65% vs 38%, p<0.01). At the time of the first T-Ab detection, an ultrasonography pattern of a hypoechogenic thyroid gland was noted in 59% of subgroup I patients and in 25% of subgroup II patients (p<0.05). At the same time, TSH>4.5 mlU/I was shown in 30 and 7% of patients of subgroups I and II, respectively (p<0.05). In the patients with the repeated positivity of both T-Ab (subgroup I) subclinical hypothyroidism developed in all patients within 4 yr after the first detection of T-Ab. On the contrary, the clinical course in patients with isolated antiTPO positivity (subgroup II) was milder with 11% developing subclinical hypothyroidism within 4 yr after the first antiTPO detection (p<0.001). The data shed new light on the relative diagnostic value of thyroid antibodies, ultrasonography and functional examination for an early detection of thyroid autoimmunity of adult diabetic patients.

Determining when to operate on patients with Hashimoto's thyroiditis with nodular lesions: the role of ultrasound-guided fine needle aspiration cytology

OBJECTIVE

To elucidate the role of ultrasound-guided fine needle aspiration cytology (FNAC) in determining whether to request an operation.

STUDY DESIGN

Twenty-four consecutive patients (23 women and 1 man) with Hashimoto's thyroiditis combined with nodular lesions revealed by ultrasonography were included in the study. Ultrasound-guided FNAC was performed on their thyroid tissue compatible with Hashimoto's thyroiditis and nodular lesions.

RESULTS

Two of 24 patients (8.3%) had papillary thyroid cancer, which was diagnosed from aspirates of 31 nodular lesions and confirmed by operative pathologic findings.

CONCLUSION

If a patient with Hashimoto's thyroiditis has nodular lesions shown by ultrasonography, ultrasound-guided FNAC is helpful in elucidating the nature of the lesion and determining whether to request an operation.

Brain perfusion abnormalities in patients with euthyroid autoimmune thyroiditis

PURPOSE

Brain perfusion abnormalities have recently been demonstrated by single-photon emission computed tomography (SPECT) in rare cases of severe Hashimoto's thyroiditis (HT) encephalopathy; moreover, some degree of subtle central nervous system (CNS) involvement has been hypothesised in HT, but no direct evidence has been provided so far. The aim of this study was to assess cortical brain perfusion in patients with euthyroid HT without any clinical evidence of CNS involvement by means of 99mTc-ECD brain SPECT. Sixteen adult patients with HT entered this study following informed consent.

METHODS

The diagnosis was based on the coexistence of high titres of anti-thyroid auto-antibodies and diffuse hypoechogenicity of the thyroid on ultrasound in association with normal circulating thyroid hormone and TSH concentrations. Nine consecutive adult patients with non-toxic nodular goitre (NTNG) and ten healthy subjects matched for age and sex were included as control groups. All patients underwent 99mTc-ECD brain SPECT. Image assessment was both qualitative and semiquantitative. Semiquantitative analysis was performed by generation of four regions of interest (ROI) for each cerebral hemisphere--frontal, temporal, parietal and occipital--and one for each cerebellar hemisphere in order to evaluate cortical perfusion asymmetry. The Asymmetry Index (AI) was calculated to provide a measurement of both magnitude and direction of perfusion asymmetry.

RESULTS

As assessed by visual examination, 99mTc-ECD cerebral distribution was irregular and patchy in HT patients, hypoperfusion being more frequently found in frontal lobes. AI revealed abnormalities in 12/16 HT patients, in three of the nine NTNG patients and in none of the normal controls. A significant difference in the mean AI was found between patients with HT and both patients with NTNG (p<0.003) and normal controls (p<0.001), when only frontal lobes were considered.

CONCLUSION

These results show the high prevalence of brain perfusion abnormalities in euthyroid HT. These abnormalities are similar to those observed in cases of severe Hashimoto's encephalopathy and may suggest a higher than expected involvement of CNS in thyroid autoimmune disease.

[Update endocrinology: Thyroid sonography]

Thyroid ultrasound has developed to be an important diagnostic method. Thyroid and extrathyroid diseases can be differentiated. Ultrasonography shows an exact image of thyroid structures in which typical images for some pathological entities can be observed. Clinical experience with thyroid diseases is essential when using thyroid ultrasonography. Thyroid ultrasonography does not correlate with histopathologic findings very well. Therefore fine needle aspiration biopsy should be used without hesitation. Solitary thyroid nodules larger than 1-1.5 cm in diameter or other potentially malignant structures must be investigated by a fine needle aspiration biopsy. Cytopathologic results of a fine needle aspiration biopsy have a high accuracy, but follicular neoplasms need a histopathologic examination to discriminate between an adenoma and a follicular carcinoma. Colour-flow Doppler ultrasonography gives helpful information about the blood circulation but is not necessary for a reliable diagnostic work up of thyroid diseases. Clinical findings, laboratory results, ultrasonography and fine needle aspiration biopsy can be used alone or in combination, depending on the indication observed, to help find the accurate diagnosis.

Correlation of computerized gray-scale sonographic findings with thyroid function and thyroid autoimmune activity in patients with Hashimoto's thyroiditis

PURPOSE

The objective of this study was to retrospectively assess whether computerized gray-scale sonography can allow objective measurement of thyroid echogenicity in patients with Hashimoto's thyroiditis (HT) at various functional stages of the disease.

METHODS

Of the 77 patients with HT who were included in our study, 28 had been euthyroid, 20 had had subclinical hypothyroidism, and 29 had had clinical hypothyroidism. Of those with clinical hypothyroidism, 6 had been untreated and 23 had been receiving L-thyroxine substitution therapy. Fifty volunteers without thyroid disease served as a control group. Thyroid echogenicity was evaluated by computerized gray-scale sonography as mean tissue density (MTD) +/- standard deviation; the echogenicity of the prethyroid muscles served as a control of the system variability.

RESULTS

The MTD was significantly lower for the patients with HT (15.9 +/- 4) than for the control subjects (24.3 +/- 3; p < 0.05). Moreover, a significant difference was found between the MTD values of euthyroid patients with HT (18.9 +/- 3.4) and hypothyroid patients with HT analyzed either as a group (14.3 +/- 3.8) or separately for subclinical hypothyroidism (14.9 +/- 3.8) and clinical hypothyroidism (13.9 +/- 3.7; p < 0.05). The lowest MTD was found in patients with untreated clinical hypothyroidism (11.1 +/- 4.3), with a significant difference (p < 0.05) compared to all other groups of patients. Untreated patients with clinical hypothyroidism also showed the highest mean anti-thyroid peroxidase autoantibody levels (1,286 +/- 177 IU/ml versus 570 +/- 489 IU/ml for L-thyroxine-treated patients; p < 0.05), although no correlation between the MTD values and anti-thyroid peroxidase autoantibody levels was found in any group of patients.

CONCLUSIONS

Computerized gray-scale sonography provides an objective measure of thyroid hypoechogenicity, which correlates well to the clinical stages of HT. Use of this modality may prove beneficial in the diagnosis and follow-up of patients with HT.

High prevalence of autoimmune thyroiditis in patients with polycystic ovary syndrome

OBJECTIVE

To investigate the prevalence of autoimmune thyroiditis (AIT) in patients with polycystic ovary syndrome (PCOS).

DESIGN

Over a period of 30 months, 175 patients with PCOS were recruited to a prospective multicenter study to evaluate thyroid function and morphology; 168 age-matched women without PCOS were studied as a control group.

METHODS

PCOS was defined as a- or oligomenorrhea, hyperandrogenism and exclusion of other disturbances of estrogen or androgen synthesis. All laboratory parameters were determined with automated immunoassays. Thyroid morphology was assessed by ultrasound.

RESULTS

PCOS patients were characterized by an increased LH/FSH ratio, low progesterone, elevated testosterone and a high prevalence of hirsutism (PCOS 83%, control 3%; mean hirsutism score 12+/-5 and 3+/-2 respectively), but no differences in estrogen levels were found. Thyroid function and thyroid-specific antibody tests revealed elevated thyroperoxidase (TPO) or thyroglobulin (TG) antibodies in 14 of 168 controls (8.3%), and in 47 of 175 patients with PCOS (26.9%; P<0.001). On thyroid ultrasound, 42.3% of PCOS patients, but only 6.5% of the controls (P<0.001) had a hypoechoic tissue typical of AIT; while thyroid hormone levels were normal in all subjects, PCOS patients had a higher mean TSH level (P<0.001) and a higher incidence of TSH levels above the upper limit of normal (PCOS 10.9%, controls 1.8%; P<0.001).

CONCLUSION

This prospective study demonstrates a threefold higher prevalence of AIT in patients with PCOS, correlated in part with an increased estrogen-to-progesterone ratio and characterized by early manifestation of the disease.

Prevalence of antithyroid microsomal antibody in thyroid patients of endemic goitre area

The region of greater Mymensingh known for iodine endemicity, recently came under iodine supplementation as a result of mandatory universal iodination of salt program. Autoimmune thyroid diseases (AITD) are among the most common human autoimmune disorders & presence of autoantibodies to the microsomal antigen (AntiMCAb) is a hallmark of disease activity. Both iodine deficiency & iodine supplementation precipitate increase rate of autoimmunity to the thyroid gland. Study was undertaken to determine prevalence of AntiMCAb positive cases among patients with various thyroid diseases. High resolution ultrasound (HRUS), serum thyroid hormone assays & scintiscan were used to classify the thyroid patients into 8 categories. 221 patients were studied during the stipulated period of 3 months. Male patients were 60 & female patients were 161. Age ranged from 11 to 65 years with median age 29.4 years. AntiMCAb test were done with radioimmunoassay (RIA). 126 patients had antimicrosomal antibody (57.01%). All form of hypothyroid (atrophic, goitrous, Hashimoto's) have very high rate of AntiMCAb positive cases. Highest 89.28% were seen in patients showing feature of Hashimoto's thyroiditis or generalized feature of AITD in HRUS with hypothyroidism, followed had 61.29% positive cases, However, antithyroid antibody was found in all form of thyroid disorders. Nodular goiter had 21.73% antiMCAb positive cases. AntiMCAb found positive at the rate of 33.33% in euthyroid patients with HRUS feature of AITD & diffuse euthyroid goiter, 40% in subclinical hypothyroid, 40% in subclinical hyperthyroid. Female rated higher in range of antimicrosomal antibody positivism. 59% of all thyroid patients among female subjects were AntMCAb positive, where as 51.67% male thyroid patients were positive. Highest number of positive cases found in the 30-35 age group. No definite pattern, however, was observed among age distribution. 20 age matched sample from patients unsuspected of thyroid disease shows 10% AntiMCAb positive compared to 73.33% of the same among same age group of thyroid patients. Frank Hashimoto's thyroiditis with positive antiMCAb and hypothyroidism were all detected by HRUS.

Increased prevalence of sublinical brain perfusion abnormalities in patients with autoimmune thyroiditis: evidence of Hashimoto's encephalitis?

OBJECTIVES

Hashimoto's encephalitis is a term which describes encephalopathy associated with autoimmune thyroiditis, but it is not based on evidence, whether Hashimoto's encephalitis is a distinct clinical entity by itself. In previously reported cases of Hashimoto's encephalitis, abnormal brain perfusion studies have been reported. The aim of this study was to evaluate the prevalence of brain perfusion abnormalities in euthyroid patients with autoimmune thyroiditis.

METHODS

99mTc Ethyl cystein dimer (ECD) single photon emission computed tomography (SPECT) studies were performed in a study group of 41 euthyroid patients with autoimmune thyroiditis and a matched control group of 35 healthy individuals. All study participants had a normal neurological investigation and a detailed neurological history taking. Individuals with known or suspected morphological brain abnormalities were excluded from the study. Zung's Self-Rating Anxiety Scale (SAS) and Zung's Self-Rating Depression Scale (SDS) were used to detect depression and mood disorders. Automatic quantification of perfusion was performed with both a voxel-based analysis as well as a volume-of-interest (VOI) based analysis of 46 predefined cortical and subcortical regions. The findings from both groups were compared to a reference template.

RESULTS

In the voxel-based analysis, there was a significant difference between patients and controls in the mean volume of perfusion defects deviating 2SD below the normal values (21.8 ml vs. 10.4 ml; P = 0.02). Hyperperfused areas, however, did not differ significantly between study patients and controls. A significant correlation of the perfusion defects with time since diagnosis of autoimmune thyroiditis was seen (r = 0.42). In the VOI-based analysis, abnormal regions were more frequent in the study group when compared to controls (P < 0.01) However, no topographic pattern was apparent. Regarding neurological findings, no significant difference was found between study patients and controls. However, both the SAS and SDS scores differed significantly between the two groups, but there was neither a correlation between the two scores and perfusion abnormalities nor an association with depression in our study group.

CONCLUSIONS

These findings of impaired brain perfusion in patients with autoimmune thyroiditis further strengthen the hypothesis of a possible cerebral involvement in autoimmune thyroiditis in individual cases. The presence of cerebral hypoperfusion suggests a cerebral vasculitis as the most likely pathogenetic model.

Image texture analysis of sonograms in chronic inflammations of thyroid gland

The current practice in assessing sonographic findings of chronic inflamed thyroid tissue is mainly qualitative, based just on a physician's experience. This study shows that inflamed and healthy tissues can be differentiated by automatic texture analysis of B-mode sonographic images. Feature selection is the most important part of this procedure. We employed two selection schemes for finding recognition-optimal features: one based on compactness and separability and the other based on classification error. The full feature set included Muzzolini's spatial features and Haralick's co-occurrence features. These features were selected on a set of 2430 sonograms of 81 subjects, and the classifier performance was evaluated on a test set of 540 sonograms of 18 independent subjects. A classification success rate of 100% was achieved with as few as one optimal feature among the 129 texture characteristics tested. Both selection schemes agreed on the best features. The results were confirmed on the independent test set. The stability of the results with respect to sonograph setting, thyroid gland segmentation and scanning direction was tested.

High prevalence of thyroid ultrasonographic abnormalities in primary aldosteronism

The study was performed to evaluate the prevalence of thyroid abnormalities detected by ultrasonography and, in particular, of multinodular nontoxic goiter in primary aldosteronism. We analyzed 80 consecutive of patients with primary hyperaldosteronism (40 with unilateral adenoma and 40 with idiopathic hyperaldosteronism) and 80 normotensive healthy controls, comparable for age, sex, iodine intake, and geographical area. Blood pressure, thyroid palpation, thyroid function, and ultrasonography were evaluated. The prevalence of ultrasonographic thyroid abnormalities was 60% in primary aldosteronism and 27% in controls (p < 0.0001). There was a statistically significant difference in prevalence of these abnormalities in unilateral adenoma and idiopathic hyperaldosteronism with respect to controls (p < 0.05 and p < 0.0001, respectively). The prevalence of multinodular nontoxic goiter in idiopathic hyperaldosteronism was higher than in controls (p < 0.001) and, in particular, in female patients. From these data it seems to be worth considering the existence of primary hyperaldosteronism in patients with multinodular goiter and hypertension.