Reference values for Doppler ultrasound parameters of the thyroid in a healthy iodine-non-deficient population.

The aim of this study was to describe normal Doppler parameter values in the thyroid arteries in an iodine-replete region. 165 individuals were randomly selected in a community located in the south-east of Brazil. We obtained a clinical history on each subject and determined serum thyrotropin, antiperoxidase antibodies, thyrotropin receptor antibody (TRAb) and thyroid volumes through ultrasound. Subjects with thyroid disease and those under 20 years of age were excluded. 84 representative subjects (30 men and 54 women) remained. The systolic peak velocity (SPV), resistive index (RI) and pulsatility index (PI) in the superior and inferior thyroid arteries were measured using a 5-12 MHz linear probe. Except for the RI, the distribution of all Doppler parameters was non-gaussian. The median and mean references for the SPV, RI and PI were 24.80 cm s(-1) and 25.85 cm s(-1), 0.60 and 0.62, and 0.98 and 1.04, respectively, for superior thyroid arteries; these reference values for the inferior thyroid artery were 20.92 cm s(-1) and 21.50 cm s(-1), 0.57 and 0.57, and 0.84 and 0.88, respectively (p<0.001). Women had greater SPV values (p<0.01). We have determined reference thyroid Doppler parameter values in our iodine-non-deficient population and prepared tables by sex and age.

Differentiation between the two types of amiodarone-associated thyrotoxicosis using duplex and amplitude Doppler sonography.

PURPOSE: To evaluate the usefulness of Doppler parameters in the differentiation between the two types of amiodarone-associated thyrotoxicosis (AAT). MATERIAL AND METHODS: One hundred thirty-seven individuals were selected at our institution. They were divided into four groups: 84 normal subjects (N), 30 euthyroids taking amiodarone (A), 14 AAT type 1 patients (AAT1), and nine AAT type 2 patients (AAT2). Each AAT type was classified according to (131)I uptake and clinical outcome. Blindly, the resistance and pulsatility indexes (RI, PI), systolic peak velocity, and color pixel density (CPD) were calculated. RESULTS: AAT1 had greater CPD than AAT2 (P = 0.02). The latter group had similar vascularization to the N and A groups (P = 0.45). The area under the receiver operating characteristic (ROC) curve showed that systolic peak velocity in the inferior thyroid arteries and CPD were the best parameters in the differentiation between AAT type 1 and AAT type 2 (Az = 0.83 and 0.84, respectively). Impedance indexes were useless. CONCLUSION: Our results demonstrate that objective tests such as systolic peak velocities in the thyroid arteries and CPD are reliable parameters for differentiating between the two types of AAT.

Types of arrhythmia among cases of American trypanosomiasis, compared with those in other cardiology patients.

The frequencies of each type of arrythmia were investigated, by age and sex, among 3056 Brazilian patients with cardiac arrhythmia. Each patient investigated had been tested serologically for American trypanosomiasis and 1013 had been found seropositive for the disease. In general, the seropositive 'chagasic' patients were each likely to be suffering from more types of arrhythmia than the seronegative 'non-chagasic', with means of 1.81 and 1.03 types/patient, respectively. Right-branch bundle blocks (RBBB), ventricular extrasystoles (VE) and left anterior hemiblocks (LAHB) were the commonest cardiac arrhythmias among the chagasic patients, and each of these types of arrhythmia (alone or with other types of arrythmia) was more frequent in the chagasic patients than the non-chagasic. The incidence of RBBB among the arrhythmic varied significantly with age in the non-chagasic patients (increasing with age among both the males and females) but not among the chagasic subjects. When the frequencies of each type of arrythmia and each combination of types were compared, the co-occurrence of RBBB and another type of arrhythmia was almost indicative of American trypanosomiasis (occurring in 30.6% of the chagasic subjects but only 2.6% of the non-chagasic). Similarly, only 0.4% of the non-chagasic patients but 7.4% of the chagasic had RBBB, VE and LAHB concurrently. However, the frequencies of RBBB in isolation (i.e. with no other, concurrent, electrocardiographic abnormality), VE in isolation, or LAHB in isolation were not significantly different in the chagasic and non-chagasic patients.