Evaluation of thyrotoxicosis during pregnancy with color flow Doppler sonography

Advances in the differential diagnosis of transient hyperthyroidism in pregnancy and Graves' disease

BACKGROUND

The occurrence of thyrotoxicosis during pregnancy is mainly attributed to gestational transient thyrotoxicosis (GTT) and Graves' disease (GD). It is important to distinguish between GTT and Graves' disease because the two diseases are treated very differently. However, a gold standard for the differential diagnosis of the two diseases is currently lacking, and the most common method of differentiation is based on past medical history and clinical presentation combined with thyroid-related antibodies.

METHODS

A literature search of the electronic databases PubMed, Embase, Medline, Google Scholar, Cochrane Library, China Knowledge Infrastructure, Wanfang Database, Chinese Scientific Journals Full Text Database and China Biomedical CD-ROM was performed. The search period ranged from journal inception until 2022. We used the following search terms in "All fields": {["thyroid" (common field) OR "thyroid" (subject line)] OR "hyperthyroidism" (common field)} AND {["pregnancy" (title) OR "pregnancy" (title)] AND "one over" (common field)} OR {["pregnancy" (common field) OR "pregnancy" (common field) OR "pregnancy" (subject line)] AND "Graves'" (common field)}.

RESULTS

In recent years, some clinical studies at home and abroad have proposed other meaningful differential indicators, such as thyroid stimulating hormone, chorionic gonadotropin, thyroid hormone levels and thyroid ultrasound.

CONCLUSION

The differential diagnostic significance of each of these indicators is summarised here with the goal of providing a better reference for the differential diagnosis of hyperthyroidism during pregnancy in clinical practice.

Scintigraphy evaluation of hyperthyroidism and its correlation with clinical and biochemical profiles

Objective

Hyperthyroidism is the excessive synthesis of thyroid hormones. Thyroid uptake scans and ultrasonography provide an accurate diagnosis of hyperthyroidism, especially when thyroid receptor antibody (TRAb) measurement is not readily available. This study explored the prevalence of various hyperthyroidism causes using retrospective scintigraphy results and evaluated their relationship with clinical, biochemical, and sonographic imaging parameters from patients who underwent ^99mTc-pertechnetate thyroid scans between 2016 and 2019 in Taif, Saudi Arabia, where literature is insufficient. Furthermore, the inappropriate use of thyroid scanning in different thyroid diseases was evaluated.

Results

The study enrolled 207 patients (mean age: 42.5 ± 14.7 years). The mean free T4, T3, antithyroid peroxidase antibody, antithyroglobulin antibody, C-reactive protein, and erythrocyte sedimentation rate levels were high. Graves’ disease was the most common diagnosis. Compared to toxic solitary/multinodular goiter, patients with Graves’ disease were usually younger, used carbimazole during both the uptake and the scan, had an enlarged thyroid gland, and had higher FT4 and FT3 levels. Inappropriate thyroid uptake and scan use was reported in approximately 10% of patients, and 25% of the patients used carbimazole during the uptake and scan. Thus, better patient education is needed to avoid misinterpreting the scan results.

Graves' disease and pregnancy

This section deals with the specificities of managing Graves' disease during pregnancy. Graves' disease incurs risks of fetal, neonatal and maternal complications that are rare but may be severe: fetal hyper- or hypothyroidism, usually first showing as fetal goiter, neonatal dysthyroidism, premature birth and pre-eclampsia. Treatment during pregnancy is based on antithyroid drugs alone, without association to levothyroxine. An history of Graves' disease, whether treated radically or not, with persistent maternal anti-TSH-receptor antibodies must be well identified. Fetal monitoring should be initiated in a multidisciplinary framework that should be continued throughout pregnancy. Neonatal monitoring is also crucial if the mother still shows anti-TSH-receptor antibodies at end of pregnancy or underwent antithyroid treatment. The risk of recurrence of hyperthyroidism in the weeks following delivery requires maternal monitoring. The long-term neuropsychological progression of children of mothers with Graves' disease is poorly known.

An Advantageous Role of Spectral Doppler Sonography in the Evaluation of Thyroid Dysfunction During the Postpartum Period

OBJECTIVES

To evaluate the diagnostic value of spectral Doppler sonography in women with thyroid dysfunction during the first postpartum year.

METHODS

This prospective observational clinical study included 83 consecutive untreated women: 32 with hyperthyroid postpartum thyroiditis, 32 with hypothyroid postpartum thyroiditis, and 19 with Graves disease, which first appeared within 12 months after delivery. Thyrotropin, free thyroid hormones, thyroid peroxidase antibodies, thyroglobulin antibodies, and thyrotropin receptor antibodies were measured. With a 7.5-MHz linear transducer, we measured the thyroid volume and peak systolic velocity (PSV) at the level of intrathyroid arteries.

RESULTS

Hyperthyroid postpartum thyroiditis appeared significantly earlier (mean ± SD, 4.4 ± 1.9 months after delivery) than hypothyroid postpartum thyroiditis (6.5 ± 2.1 months) and Graves disease (7.2 ± 2.7 months; P< .001). The thyroid volume in hyperthyroid postpartum thyroiditis (9.7 ± 6.3 mL) was significantly lower than in hypothyroid postpartum thyroiditis (14.7 ± 10.2 mL; P = .030) and Graves disease (19.4 ± 10.2 mL; P< .001). The PSV in hyperthyroid postpartum thyroiditis (9.4 ± 3.4 cm/s) was significantly lower than in hypothyroid postpartum thyroiditis (14.4 ± 3.9 cm/s; P < .001) and Graves disease (19.8 ± 7.0 cm/s; P < .001). With a cutoff level of 15 cm/s, the sensitivity and specificity of the PSV as a predictor of the correct diagnosis in hyperthyroid postpartum women were 94.7% and 96.8%, respectively. A multinomial logistic regression revealed PSV and the time after delivery at which the disorders presented as independent predictors of the differentiation between hyperthyroid postpartum thyroiditis and Graves disease (P = .003; P = .022).

CONCLUSIONS

Spectral Doppler sonography was shown to be a useful and accurate method for thyroid dysfunction evaluation during the postpartum period.

Mean peak systolic velocity of the superior thyroid artery is correlated with radioactive iodine uptake in untreated thyrotoxicosis

OBJECTIVE

To evaluate the correlation between mean superior thyroid artery peak systolic velocity (STA-PSV) and radioactive iodine uptake (RAIU) in Chinese patients with untreated thyrotoxicosis, using retrospectively and prospectively collected data.

METHODS

Patients with untreated thyrotoxicosis (n = 220) and euthyroid control subjects (n = 30) underwent thyroid function, thyroid autoantibody and thyroid ultrasonography tests. Mean STA-PSV was measured by ultrasonography. RAIU tests identified 168 patients with Graves' disease and 52 with destructive thyroiditis. Linear correlation of mean STA-PSV with 3-h and 24-h RAIU, and sensitivity, specificity and receiver operating characteristic (ROC) curves for mean STA-PSV in the differential diagnosis of Graves' disease and destructive thyroiditis were calculated.

RESULTS

Mean STA-PSV was significantly higher in Graves' disease than in destructive thyroiditis. Mean STA-PSV correlated positively and significantly with 3-h and 24-h RAIU. Area under the ROC curve of mean STA-PSV for the differential diagnosis of Graves' disease and destructive thyroiditis was 0.825 (optimum cut-off value of mean STA-PSV, 45.25 cm/s; sensitivity, 80.4%; specificity, 81.4%).

CONCLUSIONS

Detection of mean STA-PSV by ultrasonography agrees with RAIU and is useful for the differential diagnosis of thyrotoxicosis in Chinese patients.

Benign conditions of the thyroid gland

Infectious and autoimmune diseases account for the majority of benign conditions of the thyroid gland. They are usually diagnosed and followed by clinical examination and laboratory analyses, but when imaged, ultrasonography and computed tomography are the modalities of choice. In particular, fine needle aspiration under ultrasound guidance may be invaluable for diagnostic and therapeutic purposes.

Is the measurement of inferior thyroid artery blood flow velocity by color-flow Doppler ultrasonography useful for differential diagnosis between gestational transient thyrotoxicosis and Graves' disease? A prospective study

OBJECTIVE

To determine the role of peak systolic velocity, end-diastolic velocity and resistance indices of both the right and left inferior thyroid arteries measured by color-flow Doppler ultrasonography for a differential diagnosis between gestational transient thyrotoxicosis and Graves' disease during pregnancy.

METHODS

The right and left inferior thyroid artery-peak systolic velocity, end-diastolic velocity and resistance indices of 96 patients with thyrotoxicosis (41 with gestational transient thyrotoxicosis, 31 age-matched pregnant patients with Graves' disease and 24 age- and sex-matched non-pregnant patients with Graves' disease) and 25 age and sex-matched healthy euthyroid subjects were assessed with color-flow Doppler ultrasonography.

RESULTS

The right and left inferior thyroid artery-peak systolic and end-diastolic velocities in patients with gestational transient thyrotoxicosis were found to be significantly lower than those of pregnant patients with Graves' disease and higher than those of healthy euthyroid subjects. However, the right and left inferior thyroid artery peak systolic and end-diastolic velocities in pregnant patients with Graves' disease were significantly lower than those of non-pregnant patients with Graves' disease. The right and left inferior thyroid artery peak systolic and end-diastolic velocities were positively correlated with TSH-receptor antibody levels. We found an overlap between the inferior thyroid artery-blood flow velocities in a considerable number of patients with gestational transient thyrotoxicosis and pregnant patients with Graves' disease.

CONCLUSIONS

This study suggests that the measurement of inferior thyroid artery-blood flow velocities with color-flow Doppler ultrasonography does not have sufficient sensitivity and specificity to be recommended as an initial diagnostic test for a differential diagnosis between gestational transient thyrotoxicosis and Graves' disease during pregnancy.

A semi-quantitative approach to compare high-sensitivity power Doppler sonography and conventional power Doppler sonography in the assessment of thyroid vascularity

BACKGROUND

Ultrasound is a useful imaging tool in the assessment of thyroid glands, and Doppler ultrasound helps in the evaluation of thyroid vascularity. This study was undertaken to evaluate the difference in the thyroid vascularity demonstrated on the state-of-the-art high-sensitivity power Doppler sonography (HSPDS) and the conventional power Doppler sonography (PDS), and to investigate the feasibility of using a customized algorithm with image-processing software for semi-quantitative assessment of thyroid vascularity.

METHODS

A total of 25 healthy volunteers were included in the study, and each subject had two thyroid ultrasound examinations with HSPDS and PDS, respectively. High sensitivity and conventional power Doppler sonograms of the thyroid glands were taken and recorded. To evaluate the vascularity of thyroid lobes quantitatively, a customized algorithm using the software Matlab was developed and used to analyze the ultrasound images. The vascularity of thyroid lobe (i.e., region of interest, ROI) was expressed as the vascular index (VI), which is the ratio of the number of color pixels to the total number of pixels within the ROI.

RESULTS

Results showed that thyroid vascularity was detected in all thyroid lobes on both HSPDS and PDS. The mean VI of the thyroid lobes on HSPDS (right lobe, 0.31 +/- 0.08; left lobe, 0.32 +/- 0.07) was significantly higher than on PDS (right lobe, 0.18 +/- 0.09; left lobe, 0.16 +/- 0.08) (p < 0.05). There was no significant difference in the VI between the right and left thyroid lobes (p >0.05). On HSPDS, 96% of the thyroid lobes showed a VI <0.5, while 96% of thyroid lobes had a VI <0.3 on PDS.

CONCLUSIONS

HSPDS is more sensitive than PDS in the detection of thyroid vascularity. The developed algorithm can quantify the color pixels on power Doppler sonograms, which is useful for objective assessment of thyroid vascularity.