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

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.

Comparison between peak systolic velocity of the inferior thyroid artery and technetium-99m pertechnetate thyroid uptake in differentiating Graves' disease from thyroiditis

OBJECTIVES

The differentiation between the various etiologies of thyrotoxicosis, including those with hyperthyroidism (especially Graves' disease [GD], the most common cause of hyperthyroidism) and without hyperthyroidism (like thyroiditis), is an important step in planning specific therapy. Technetium-99m (99mTc) pertechnetate thyroid scanning is the gold standard in differentiating GD from thyroiditis. However, this technique has limited availability, is contraindicated in pregnancy and lactation, and is not helpful in cases with history of recent exposure to excess iodine. The aim of this study was to identify the diagnostic value of the peak systolic velocity of the inferior thyroid artery (PSV-ITA) assessed by color-flow Doppler ultrasound (CFDU) and compare the sensitivity and specificity of this method versus 99mTc pertechnetate thyroid uptake.

SUBJECTS AND METHODS

We prospectively analyzed 65 patients (46 with GD and 19 with thyroiditis). All patients were evaluated with clinical history and physical examination and underwent 99mTc pertechnetate scanning and measurement of TRAb levels and PSV-ITA values by CFDU. The diagnosis was based on findings from signs and symptoms, physical examination, and 99mTc pertechnetate uptake.

RESULTS

Patients with GD had significantly higher mean PSV-ITA values than those with thyroiditis. At a mean PSV-ITA cutoff value of 30 cm/sec, PSV-ITA discriminated GD from thyroiditis with a sensitivity of 91% and specificity of 89%.

CONCLUSION

Measurement of PSV-ITA by CFDU is a good diagnostic approach to discriminate between GD and thyroiditis, with sensitivity and specificity values comparable to those of 99mTc pertechnetate thyroid uptake.

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Zusammenfassung. Die Sonografie der Schilddrüse mit hochauflösenden Schallsonden ist das erste und meist einzige bildgebende Untersuchungsverfahren zur Beurteilung der Schilddrüse. Schilddrüsenerkrankungen können bei Darstellung einer normal volumigen und homogen strukturierten sowie unauffällig vaskularisierten Schilddrüse weitgehend ausgeschlossen werden. Die B-Bild-sonografische Real-time-Beobachtung der Schilddrüse (Pulsatilität, Kompressibilität, Schluckverschieblichkeit) ermöglicht in vielen Fällen nicht nur die Beurteilung der Morphologie, sondern gibt auch, zusammen mit klinischen Befunden, einschliesslich basalem TSH, Hinweise auf die Funktion. Weitere Informationen werden durch die Farbdopplersonografie mit Darstellung der Vaskularisation erhalten. Die Mehrzahl der detektierten Knoten werden als Zufallsbefund entdeckt und sind harmlos. Unter der grossen Zahl von benignen Schilddrüsenknoten müssen die sehr seltenen Malignome herausgefunden werden [1-11–4]. Die sonografisch gesteuerte Feinnadelpunktion trägt zur Sicherung der Diagnose Malignom bei. Interventionell besteht zudem die Möglichkeit der sonografisch gesteuerten Sklerosierung von Zysten und autonomen Schilddrüsenadenomen [5-15].

The Sonographic Features of the Thyroid Gland After Treatment with Radioiodine Therapy in Patients with Graves' Disease

The aim of the study was to describe the typical sonographic features of the thyroid gland in patients with Graves' hyperthyroidism after radioiodine therapy (RIT). Thirty patients (21 female and 9 male) with a mean age of 53 y (standard deviation [SD] ± 11.3) and with previous Graves' disease who had been successfully treated with RIT were enrolled in the study. All were hypothyroid or euthyroid after treatment. The thyroid ultrasound was carried out by a single experienced operator with an 8-MHz linear transducer. Volume, vascularity, echogenicity and echotexture of the glands were noted. The presence of nodules and lymph nodes was also documented. The mean volumes of the right lobe were 2.4 mL ± 2.9 SD (0.6-14) and the left lobe were 1.8 mL ± 1.9 SD (0.4-9.1), with a mean total volume of 4.2 mL ± 4.7 SD (1.3-19.1). Of those who had a pre-treatment ultrasound (23%), the percentage reduction in volume was 87% (p < 0.05); 93% of the glands were hypovascular, with the remaining 7% showing normal vascularity. The glands were hyperechoic and of coarse echotexture. Overall, the sonographic features of the post-RIT gland included a significantly reduced mean total volume of 4.2 mL, hypovascularity, coarse echotexture and hyperechogenicity.

Comparison of thyroid blood flow and uptake indices using technetium-99m pertechnetate in patients with graves' disease and euthyroid subjects

Objective: The aim of the present study was to evaluate parameters of early blood flow (EBF) including duration of EBF, perfusion index (PI), uptake indexes 1 and 2 (UI1 and UI2) derived from dynamic thyroid scintigraphy in patients with Graves’ disease (GD), and euthyroid (EI). Maximum instant uptake and maximum uptake of the thyroid gland were also assessed.

Methods: A total of 50 patients with GD and EI were included in this study. Each patient underwent two dynamic scans of 1-minute (20 images at 3 seconds) and 20-minute (20 images at 1 minute) with ^99mTcO4. The time-activity curve of a 1-minute scan was employed to derive EBF parameters; likewise, the time-activity curve of a 20-minute scan was used to determine maximum instant uptake, and the gradient of the curve from the 10th to 20th minute was used to assess maximum uptake.

Results: Values of EBF duration, PI, UI1, UI2, and maximum instant uptake were significantly lower in patients with GD than in those with EI (p<0.05). The calculated gradient of the second half of the curves for all of the patients ranged from 0 to 0.88 and was significantly higher in patients with GD than in those with EI.

Conclusion: Lower values of PI, UI1, UI2 and durations of EBF, along with faster maximum instant uptake in patients with GD in comparison to EI are indicators of a heightened desire for hyper-functioning thyroid glands of patients with GD to absorb ^99mTcO4. Additionally, because of the uprising gradient at the end of the 20-minute time-activity curve, a maximum thyroid uptake of ^99mTcO4 was achieved at more than 20 minutes after the radiopharmaceutical injection.

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.

Superior thyroid artery mean peak systolic velocity for the diagnosis of thyrotoxicosis in Japanese patients

Thyrotoxicosis with diffuse thyroid disease can be caused by Graves' disease (GD) or destructive thyroiditis (DT). Optimal treatment of the underlying condition requires a prompt and accurate method for the diagnosis of thyrotoxicosis. This study evaluated measurement of the mean peak systolic velocity of the superior thyroid artery (STA-PSV) by ultrasonography in detecting thyrotoxicosis in Japanese patients. We recruited 44 patients with untreated GD, 13 with DT, 55 with treated GD, and 49 subjects without thyroid disease. Blood samples were taken to analyze thyroid function and STA-PSV was measured by ultrasonography. The mean STA-PSV was the highest in the untreated GD group, followed by treated GD patients and then those with DT. Receiver operating characteristic curves of the STA-PSV values demonstrated that the area under the curve required discriminating untreated GD from DT was 0.941. The optimal sensitivity and specificity were 83.7% and 92.3%, respectively, using 45 cm/sec as the cutoff value. In conclusion measurement of STA-PSV by ultrasonography is useful for the diagnosis of thyrotoxicosis in Japanese patients.

The role of imaging in Graves’ disease: A cost-effectiveness analysis

According to many guidelines, scintigraphy remains the first suggested diagnostic procedure in hyperthyroid patients in spite of the widespread availability of ultrasounds. The aim of this study was to evaluate the cost-effectiveness of sonography versus scintigraphy in the management of Graves's disease, and to assess ultrasound features suggesting cancer in detecting thyroid nodules. Among 1470 hyperthyroid patients evaluated in our department from 2002 to 2005, 426 (29%) had Graves' disease: echographic and scintigraphic features were not suggestive of GD in 20/426 (4.8%) and 11/426 (2.6%) patients, respectively (p=0.763), even if one of the two procedures was almost always diagnostic. Ultrasound identified 68/426 (16%) patients with a concomitant solid lesion, while scintigraphy detected only 9/426 (2.1%) "cold" nodules (p<0.001). Thyroid cancer was diagnosed in 30/68 (47.7%) patients. Malignancy presented at ultrasound investigation blurred margins (26.7% versus 15.8%), microcalcifications (33.3% versus 28.9%) and an anteroposterior and transverse diameter ratio>or=1 (73.3% versus 71.1%); more frequently than benign nodules, but this was not statistically significant. The total cost to obtain a diagnosis by ultrasound was euro14645.34 (euro13312.5 for echography+euro1332.84 for scintigraphy in the 29 patients "negative" at echographic evaluation for GD) versus euro19922.71 by scintigraphy (euro19578.96 for scan+euro343.75 for ultrasounds in the 11 patients "negative" at scintigraphy). Our data show no difference in terms of diagnosis between sonography and scintigraphy. Indeed, scintigraphy was less sensitive in detecting nodules (often of malignant nature) than ultrasound, and, moreover, with a consequent increase of the direct cost of nodule management when scintigraphy is the first line procedure. In conclusion, according to our results, we suggest that ultrasounds with color-Doppler evaluation should be performed as first step in all hyperthyroid patients, and that scintigraphic examination should be limited only to the uncommon cases, where physician's observation, laboratory assays and/or ultrasounds are not diagnostic.

Color flow Doppler sonography for the etiologic diagnosis of hyperthyroidism

Color flow Doppler sonography (CFDS) is gaining importance for the functional evaluation of the thyroid disorders. We aimed to determine the value of CFDS for the etiological diagnosis of hyperthyroidism. Fifty-five patients with hyperthyroidism (29 Graves' disease [GD] and 26 toxic adenoma [TA]), 24 patients with Hashimoto's thyroiditis (HT), and 39 euthyroid controls were included. Etiological diagnoses were carried out using standard methods. Conventional gray scale sonography was performed, followed by CFDS. Doppler patterns of the glands were scored and peak systolic velocity (PSV) measurements were obtained from intrathyroidal, perithyroidal, and perinodular vasculature. Vascular patterns were significantly more prominent, and the mean PSV values were significantly higher in the GD patients compared to the HT patients ( p < 0.001) and controls ( p < 0.001). Perinodular and intranodular signals and the mean perinodular PSV values were significantly higher in TAs compared to controls. CFDS could differentiate the untreated GD from the HT, which had similar gray scale findings. Hot nodules could also be differentiated from cold nodules with more prominent vascular patterns and significantly higher PSV values. As an inexpensive, fast, and noninvasive imaging procedure, CFDS could be helpful in the initial clinical evaluation and may avoid scintigraphy in a substantial number of thyrotoxic patients.

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.

Relationship between the sonographic appearance of the thyroid and the clinical course and autoimmune activity of Graves' disease

PURPOSE

The aim of this study was to investigate the relationship between thyroid echogenicity and clinical course/immunologic parameters in Graves' disease.

METHODS

Two hundred and six outpatients with Graves' disease (31 men, 175 women; 46 +/- 23 years old) were studied with thyroid sonography and color Doppler sonography. Forty-five patients were treated for active hyperthyroidism, 161 were euthyroid (85 immediately before withdrawal of antithyroid drug at maintenance doses, 76 in stable remission after withdrawal of antithyroid treatment). Free triiodothyronine, free thyroxine, thyrotropin, and disease-specific autoantibodies (antithyrotropin-releasing hormone antibody) were determined in all patients.

RESULTS

The ultrasound images were classified on the basis of homogeneous, finely unhomogeneous, or micronodular appearance. The proportion of unhomogeneous plus micronodular patterns was greater in hyperthyroid (77.8%) than in euthyroid patients (62.1%). In the latter group, the pattern distribution was significantly different in patients who were antibody positive relative to patients who were antibody negative (p < 0.01). In the stable remission subgroup, the pattern distribution differed according to thyrotropin levels (p < .01). There was a correlation between echopattern and color Doppler sonography as vascularization variables progressively increased in the transition from homogeneous to unhomogeneous and micronodular echopattern (most evident echotexture changes).

CONCLUSIONS

A sonographic-based classification in Graves' disease can distinguish subgroups of patients with different clinical courses and disease activity. This procedure is easy to perform and correlates well with clinical findings.

Doppler evaluation of pediatric goiter: effect of mandatory iodination

PURPOSE

The aim of this study was to evaluate the hemodynamic status of the thyroid in children with goiter after the use of iodinated dietary salt for 3 years in a region of endemic iodine deficiency.

METHODS

Sixty-six children between 7 and 12 years of age were included in the study. Three groups were constituted according to sonographically measured thyroid volume and urinary iodine excretion levels. Group 1 included 11 children with thyroid volumes greater than the 97th percentile according to age and sex criteria suggested by the World Health Organization International Council for Control of Iodine Deficiency Disorders and urinary iodine level lower than 100 microg/l. Group 2 included 30 children with thyroid volumes greater than the 97th percentile and urinary iodine level equal to or higher than 100 microg/l. The control group included 25 children who had normal thyroid volume and urinary iodine level. All children were examined by thyroid duplex sonography. Peak systolic velocity (PSV) and resistance index (RI) were measured in the inferior thyroid artery bilaterally.

RESULTS

PSV in group 1 was significantly higher than in group 2 and in the control group (P < 0.05 and P < 0.01, respectively). There was no significant difference between the PSV of group 2 and the control group. The RI in groups 1 and 2 was significantly lower than in the control group (P < 0.01 and P < 0.01, respectively). There was no significant difference between the RIs of group 1 and group 2.

CONCLUSIONS

These findings suggest an effect of iodination on thyroid hemodynamics before the size of the hyperplastic thyroid returned to normal, in keeping with normalization of the urinary iodine level.

Power Doppler ultrasound imaging for quantification of urinary bladder neck blood flow changes

This study was designed to evaluate power Doppler imaging for assessment of urinary bladder neck blood flow in comparison with laser Doppler flowmetry (LDF) in an animal model. Transrectal power Doppler ultrasound (US) and LDF of the urinary bladder neck were performed in three anesthetized pigs during comparative cystometry. Normal saline (NaCl) was used for the first run, followed by a second run with 0.2 mol/L potassium chloride (KCl). Standardized sonographic equipment settings (Acuson Sequoia 512); MountainView, CA) were used for power Doppler imaging. Computer-assisted calculation of color pixel density (CPD) of power Doppler images was performed using Scion Image) software image analysis. Tissue perfusion units (TPU) were measured using a BLF21 laser Doppler flowmeter (Transonic Systems Inc., Ithaca, NY, USA). The power Doppler results were compared with the findings obtained by LDF. NaCl filling resulted in a mean CPD increase at the bladder neck from 18.65 (+/- 1.78) at empty bladder to 37.8 (+/- 1.84) at 100 mL and to 88.32 (+/- 1.35) at full bladder capacity (C(max)) of 270 mL, respectively. With KCl filling, a mean CPD increase from 18.65 (+/- 1.78) to 59.63 (+/- 0.5) at 100 mL and 110.82 (+/- 2.98) at full bladder capacity (270 mL) was observed. The CPD increase was significantly higher for KCl than with NaCl (p < 0.001). With NaCl filling, bladder neck blood flow increased from 22 TPU (empty) to 46 TPU (100 mL) and 62.5 TPU at C(max), compared to 22 TPU, 50 TPU and 102.5 TPU with KCl. CPD and TPU measurements showed a strong correlation at p = 0.01. In conclusion, transrectal power Doppler US image quantification is a feasible and accurate method for assessing blood flow changes in the urinary bladder neck.

Variability of thyroid blood flow Doppler parameters in healthy women

The purpose of this study was to estimate variability of flow Doppler parameters in the superior thyroid artery (STHA) during the menstrual cycle in young women and to explore the influence of endogenous 17-b-estradiol (E2) and progesterone (PRG) on the velocity waveform. The plasma concentration of these hormones was correlated with flow velocities, pulsatility index (PUI), resistance index (RI) and acceleration index (accI) and time (accT), which were measured with color-coded duplex sonography 8 times during the cycle in 14 healthy women (age range: 23 to 25 years). Coefficient of variation (CV), interclass correlation (ICC), repeatability (repC) and pooled Pearson correlation (r) coefficients were used to estimate the variability of the parameters. The highest variability was found for accI and accT: CV = 48% and 31%; ICC = 0.51 and 0.45; repC = 2.8 and 95; r = 0.37 and 0.4, respectively. The CV for flow velocities varied from 25% to 26%, ICC from 0.53 to 0.56, repC from 8 to 17 and r has a value of 0.46. The respective values for RI and PUI were: 11%, 18%; 0.48, 0.55; 0.15, 0.48; and 0.46, 0.48. The diastolic blood pressure decreased significantly by 7 mmHg (p < 0.01) in the luteal phase, whereas other physiological variables were stable during the cycle. Although the fluctuations of the flow parameters during the cycle were not statistically significant, a weak linear correlation between flow velocities and concentration of E2 was found; for mean velocity r = 0.16, p < 0.05. Impedance indices showed an increasing trend in the luteal phase, along with increase of the pulse pressure index (PPI). The results showed that variability of the flow parameters in the STHA is substantial and that higher flow velocities are associated with increase of plasma concentration of 17-b-estradiol during the menstrual cycle in young women.