Color-flow doppler sonography in patients with subclinical thyroid dysfunction

Thyroid ultrasound pattern in primary hypothyroidism is similar to Graves' disease: a report of three cases

Ultrasound can identify important characteristics in primary hypothyroidism and diffuse hyperthyroidism (Graves' disease). Therefore, sonologists are actively investigating ultrasound criteria to differentiate between these two conditions. Nevertheless, practice shows the absence of such ultrasonic landmarks. For the first time in the literature, three cases of primary hypothyroidism have demonstrated an ultrasound pattern identical to that of Graves' disease. This pattern includes the presence of goiter, marked total hypoechogenicity of the parenchyma, significantly or moderately increased blood flow intensity ('thyroid inferno'), and elevated peak systolic velocity of the superior thyroid arteries. These signs are less common in hypothyroidism compared to hyperthyroidism. Diagnostic data suggest that the pathogeneses of primary hypothyroidism and Graves' disease share the same mechanisms, leading to similar thyroid ultrasound patterns. One of these shared mechanisms is presumably thyroid overstimulation by the autonomic nervous system, which is adequate to the body's hormonal requirements in hypothyroidism but excessive in hyperthyroidism.

Duplex Hemodynamic Parameters of Both Superior and Inferior Thyroid Arteries in Evaluation of Thyroid Hyperfunction Disorders

Background

Thyrotoxicosis may be caused by Graves’ disease or destructive thyroiditis. Differentiation between causes of thyrotoxicosis is crucial as management will differ. ^99mTechnetium (Tc)-pertechnetate thyroid scintigraphy is currently the gold standard for this purpose, however, is expensive and uses ionizing radiation.

Objective

To evaluate the role of color flow Doppler Ultrasound (CDU) of the superior thyroid (STA) and inferior thyroid arteries (ITA) as an inexpensive, non-invasive tool that can aid in differentiating between Graves’ disease and thyroiditis and compare it with thyroid scintigraphy.

Methods

Sixty-nine patients with newly-diagnosed thyrotoxicosis and 30 controls were enrolled. Thyroid functions, thyroid scintigraphy, and CDU of STA and ITA with measurements of peak systolic velocity (PSV) and end diastolic velocity (EDV), were performed. According to thyroid scintigraphy results, patients were divided into two groups: 42 patients with Graves’ disease and 27 patients with thyroiditis.

Results

PSV and EDV of both STA and ITA were significantly higher in patients with Graves’ disease than thyroiditis (p-values <0.001). The STA-PSV had an equal sensitivity and specificity of 66.7%; cut-off value 76.57 cm/s, while those of STA-EDV were 73.8%, and 77.8% respectively; cut-off value 28.22 cm/s. ITA-PSV had a sensitivity and specificity of 76.2% and 77.8%, respectively; cut-off value 62.12 cm/s), while those of ITA-EDV were 78.6% and 77.8%, respectively; cut-off value 5.22 cm/s.

Conclusion

CDU parameters of the STA and ITA could be used as an alternative to thyroid scintigraphy for discriminating between Graves’ disease and thyroiditis.

Thyroid hemodynamic alterations in Egyptian patients with sickle cell disease: relation to disease severity, total body iron and thyroid function

Background: Intraparenchymal thyroid Doppler measurements might be considered a useful index of the thyroid status as well as micro-circulation elsewhere in the body among sickle cell disease (SCD) patients. The authors aim to evaluate the intra-thyroidal hemodynamic changes and thyroidal volume in SCD patients and its relation to the disease severity, and thyroid functions tests as well as iron overload state. Methods: Sixty SCD patients, randomly recruited from the regular attendants of the Pediatric Hematology Clinic, Ain Shams University, Cairo, Egypt, were studied focusing on the disease duration, the transfusion history, the recorded Hydroxyurea, and chelation therapies and the vaso-occlusive crises history. Thyroid Doppler ultrasonography [Thyroid volume, Resistance index (RI) and pulsatility index (PI)] was performed and liver & cardiac MRI were assessed. Results: Thirteen (21.7%) of the SCD patients had hypothyroidism by thyroid function tests. SCD patients had significantly higher RI and PI values and a lower thyroid volume compared to the control group. No significant correlations were found between the thyroid functions tests and the thyroid Doppler parameters; a negative correlation of the disease duration to the thyroid volume and a positive one to RI & PI values were found. The mean serum ferritin did not significantly correlate to the thyroid Doppler indices nor did Liver and cardiac MRI results. Conclusion: The authors demonstrated an increased intra-thyroidal RI & PI and a decreased thyroid volume among SCD patients which might be related to impaired thyroidal microcirculation and vasculopathy rather than iron overload.

The End-Diastolic Velocity of Thyroid Arteries Is Strongly Correlated with the Peak Systolic Velocity and Gland Volume in Patients with Autoimmune Thyroiditis

Background

The end-diastolic velocity (EDV) of thyroid arteries reflects peripheral blood flow resistance.

Objective

The aim was to evaluate EDV correlations with other Doppler sonography parameters and with clinical and biochemical variables in a sample of patients with hypothyroidism caused by chronic autoimmune thyroiditis (CAT).

Methods

A sample of 48 CAT hypothyroid patients receiving treatment with stable doses of levothyroxine was selected. The participants underwent clinical evaluation and measurement of serum thyrotropin (TSH), total triiodothyronine (T3), total thyroxine (T4), free T4, thyroid peroxidase antibodies (anti-TPO), and antithyroglobulin antibodies (anti-Tg) and Doppler sonography.

Results

The EDV of the inferior thyroid arteries (ITA-EDV) was strongly and positively correlated with the peak systolic velocity of the inferior thyroid arteries (ITA-PSV, r = 0.919), thyroid volume (r = 0.711), and thyroid visual vascularization pattern (TVP, r = 0.687). There was no correlation between ITA-EDV and the clinical variables, hormones, anti-TPO, or anti-Tg.

Conclusion

The strong correlation of ITA-EDV with ITA-PSV, TVP, and volume suggests that increased vascularization in CAT may be associated with a reduction in thyroid blood flow resistance, possibly due to an angiogenesis-induced increase in the total vascular cross-sectional area of the parenchyma.

Pre-operative ultrasound identification of thyroiditis helps predict the need for thyroid hormone replacement after thyroid lobectomy

OBJECTIVE

To evaluate whether pre-operative thyroiditis identified by ultrasound (US) could help predict the need for thyroid hormone replacement (THR) following thyroid lobectomy.

METHODS

Data from patients who underwent thyroid lobectomy in 2006-2011, were not taking THR pre-operatively, and had ≥1 month of follow-up were reviewed retrospectively. THR was prescribed for relatively elevated thyroid-stimulating hormone (TSH) and hypothyroid symptoms. The Kaplan-Meier method was used to estimate the percentage of patients who required THR at 6, 12, 18, and 24 months postoperatively, and Cox proportional hazards regression models were used to evaluate prognostic factors for requiring post-thyroid lobectomy THR.

RESULTS

During follow-up, 45 of 98 patients required THR. Median follow-up among patients not requiring THR was 11.6 months (range, 1.2 to 51.3 months). Six months after thyroid lobectomy, 22% of patients were taking THR (95% confidence interval [CI], 15-32%); the proportion increased to 46% at 12 months (95% CI, 36-57%) and 55% at 18 months (95% CI, 43-67%). On univariate analysis, significant prognostic factors for postoperative THR included a pre-operative TSH level >2.5 μ international units [IU]/mL (hazard ratio [HR], 2.8; 95% CI, 1.4-5.5; P = .004) and pathology-identified thyroiditis (HR, 2.4; 95% CI, 1.3-4.3; P = .005). Patients with both pre-operative TSH >2.5 μIU/mL and US-identified thyroiditis had a 5.8-fold increased risk of requiring postoperative THR (95% CI, 2.4-13.9; P<.0001).

CONCLUSION

A pre-operative TSH level >2.5 μIU/mL significantly increases the risk of requiring THR after thyroid lobectomy. Thyroiditis can add to that prediction and guide pre-operative patient counseling and surgical decision making. US-identified thyroiditis should be reported and post-thyroid lobectomy patients followed long-term (≥18 months).

Assessment of the effects of low-level laser therapy on the thyroid vascularization of patients with autoimmune hypothyroidism by color Doppler ultrasound

Background. Chronic autoimmune thyroiditis (CAT) frequently alters thyroid vascularization, likely as a result of the autoimmune process. Objective. To evaluate the effects of low-level laser therapy (LLLT) on the thyroid vascularization of patients with hypothyroidism induced by CAT using color Doppler ultrasound parameters. Methods. In this randomized clinical trial, 43 patients who underwent levothyroxine replacement for CAT-induced hypothyroidism were randomly assigned to receive either 10 sessions of LLLT (L group, n = 23) or 10 sessions of a placebo treatment (P group, n = 20). Color Doppler ultrasounds were performed before and 30 days after interventions. To verify the vascularity of the thyroid parenchyma, power Doppler was performed. The systolic peak velocity (SPV) and resistance index (RI) in the superior (STA) and inferior thyroid arteries (ITAs) were measured by pulsed Doppler. Results. The frequency of normal vascularization of the thyroid lobes observed in the postintervention power Doppler examination was significantly higher in the L than in the P group (P = 0.023). The pulsed Doppler examination revealed an increase in the SPV of the ITA in the L group compared with the P group (P = 0.016). No significant differences in the SPV of the STA and in the RI were found between the groups. Conclusion. These results suggest that LLLT can ameliorate thyroid parenchyma vascularization and increase the SPV of the ITA of patients with hypothyroidism caused by CAT.