Role of combined grey scale US and US tissue elastography in differentiating solid thyroid nodules

Background

Ultrasonographic (US) examination is an accurate method for detecting thyroid nodules, but its use in differentiating between benign and malignant thyroid nodules is relatively low. US elastography has been applied to study the hardness/elasticity of nodules to differentiate malignant from benign lesions thus deviating a significant group of patients from unnecessary FNAB.

Objectives

The aim of the study is to evaluate the validity of combined grey scale US and tissue elastography in differentiating benign form malignant solid thyroid nodules.

Methods

The study included 46 selected patients with solid thyroid nodules according to our inclusion and exclusion criteria. The patients underwent surgery for compressive symptoms or suspicion of malignancy on FNA cytology. US features and tissue elastography were scored according to the Rago criteria (1).

Results

On US elastography: all the 31 cases with a final diagnosis of benign nodule had a score of 1–3, while 14 of 15 (94.1%) with a final diagnosis of carcinoma had a score of 4–5, with a sensitivity of 93.3%, a specificity of 100% and an accuracy of 97.8%. Combined US and elastography reveals that hypoechogenicity/score 4–5 was most predictive of malignancy with sensitivity 80% and specificity 100%; and accuracy 93.4%.

Conclusions

US elastography seems to have great potential as a new tool for differentiating solid thyroid nodules and for recommending FNAC. Combined grey scale US features and US elastography added no significant value when compared with US elastography alone. Further prospective studies are needed.     

The clinical value of ultrasound elastography in predicting malignant thyroid nodules

Objective

This study aims to evaluate the clinical value of ultrasound elastography (USE) in providing information on the nature of the thyroid nodules. This was performed using the elastography score and strain ratio in differentiating thyroid benign and malignant nodules and the histopathological examination was used as the diagnostic standard of reference.

Methods

We examined 84 thyroid nodules in 62 patients with ultrasound elastography. Elastography score was assigned based on a four-point scale according to the classification proposed by Itoh et al. with a score of 1 (low stiffness over the entire nodule) to a score of 4 (high stiffness over the entire nodule). Thyroid strain ratio (normal tissue to lesion strain ratio) was calculated. Histopathological results were the standard reference. The area under the curve (AUC) and the best cut-off point were both obtained using receiver-operating characteristic (ROC) curve analysis. The sensitivity, specificity, and accuracy of both techniques were calculated.

Results

Fifty-four of the 84 nodules had scores of 1 and 2, and 50 of these nodules were diagnosed histopathologically as benign. Thirty of the 84 nodules had a score of 3 and 4, and 21 of these nodules were diagnosed histopathologically as malignant. The scores of 1 and 2 with Itoh criteria were significantly seen in benign nodules, whereas, scores of 3 and 4 were significantly seen in malignant nodules (p < 0.05) with sensitivity 84%, specificity 84.7%, PPV 70%, NPV 92.6% and accuracy 84.5%. The mean SR for the benign nodules and malignant ones was significantly different (2.92 ± 0.96 vs. 4.53 ± 0.82, p < 0.001). With ROC analysis, the best cut-off strain ratio point was 3.5 for differentiating benign and malignant nodules with area under the curve (AUC) = 0.87 (0.8–0.95). The sensitivity of the strain ratio was 88%, while the specificity was 86.4%, PPV = 73.3%, NPV = 94.4% and accuracy = 86.9%.

Conclusions

Both the elastographic score and strain ratio are higher in malignant nodules than those in benign ones. Ultrasound elastography can provide quantitative information on thyroid nodule helping in differentiating benign and malignant ones.     

Diagnostic utility of real-time ultrasound elastography for prediction of malignancy in solid thyroid nodules

Aim of the work

To study the diagnostic utility of real-time ultrasound elastography (USE) in predicting malignancy in thyroid nodules.

Materials and methods

Forty-five patients with solitary solid thyroid nodules were included in this study. The thyroid nodules were examined by B-mode ultrasound, color flow Doppler ultrasound, and real-time ultrasound elastography (USE). The final diagnosis was obtained from histopathological findings. Tissue stiffness on USE was scored from 1 (low stiffness over the entire nodule) to 6 (high stiffness over the entire nodule and surrounding tissue).

Results

Twenty-eight (62.2%) patients had a final diagnosis of malignancy based on histopathological evidence of malignant thyroid nodules, while 17 (37.8%) were diagnosed as benign nodules. Anteroposterior/transverse (AP/T) diameter more than 1 cm, ill-defined margins and spot micro calcifications were the most predictive conventional ultrasound patterns of malignancy. Elasticity score of 4–6 was highly predictive of malignancy (P < 0.0001), with a sensitivity of 89.3%, a specificity of 88.2% and an accuracy of 88.9%.

Conclusion

Ultrasound elastography is an accurate non invasive tool for evaluating thyroid nodules. It has more appropriate value in the differential diagnosis of thyroid malignancy and enhances the diagnostic assurance of ultrasonographers.     

Shear wave elastography versus real-time elastography on evaluation thyroid nodules: A preliminary study

Objective

To comparatively evaluate shear wave elastography (SWE) and real-time elastography (RTE) in distinguishing malignant from benign thyroid nodules.

Methods

49 patients with 64 focal thyroid nodules were enrolled and underwent SWE and RTE before surgery. SWE elasticity indices (mean, minimum and maximum value of 2-mm region of interest) of nodules were measured. For RTE, elastograms were assessed by Rago criteria and nodules with scores of 4 or 5 were classified as suspicious for malignancy. Surgery histopathologic results were adopted as diagnostic standard.

Results

Of the 64 nodules, 19 were papillary thyroid carcinomas and 45 were benign. SWE indices were significantly higher in malignant than benign nodules (P < 0.05). Areas under the ROC curves (AUC) of SWE parameters were 0.840, 0.831 and 0.788, which were not significantly different from that of RTE showed as 0.880 (P = 0.148–0.482). When the most accurate cut-off, 38.3 kPa for mean value was applied to predict malignancy, the diagnostic specificity, sensitivity, accuracy, positive predictive value and negative predictive value of SWE and RTE were 68.4% versus 79.0%, 86.7% versus 84.4%, 81.3% versus 78.1%, 68.4% versus 64.7% and 86.7% versus 83.3%, respectively (P = 0.683–1.000).

Conclusion

SWE as a promising tool can be performed in differentiating thyroid nodules with comparable results to RTE.     

Diagnostic performance of combined elastosonography scoring and high-resolution ultrasonography for the differentiation of benign and malignant thyroid nodules

Aim

To evaluate the diagnostic performance of the combined use of elstosonography (USE) scoring and high-resolution ultrasonography (HRUS) for the differentiation of benign and malignant thyroid nodule.

Patients and methods

Forty-seven consecutive patients with 66 thyroid nodules were enrolled in the present study. Thyroid surgery had been already planned for all the patients. All of them were submitted to high-resolution ultrasonography and elastography scoring at the same sitting. The latter was determined with 5-point scoring method. The examination results were compared against pathological findings as the gold standard of reference.

Results

The sensitivity, specificity, accuracy, positive predictive, and negative predictive values of HRUS in the differential diagnosis of thyroid nodules were 92.0%, 72.9%, 60.1%, 95.0%, and 63.1%, respectively, while that of ultrasound elastography scoring were 75.4%, 85.5%, 86.7%, 71.4%, and 90.5%, respectively. Combined use of both US techniques resulted in a higher diagnostic performance as it showed 95.4%, 94.8%, 95.2%, 82.3% and 98.8% sensitivity, specificity, accuracy, positive predictive, and negative predictive values, respectively.

Conclusions

The use of combined USE and HRS for the differentiation of benign and malignant thyroid nodules resulted in a high diagnostic performance and a significant statistical difference as compared to HRUS or USE alone (P = 0.003).     

Ultrasonographic criteria for fine needle aspiration of nonpalpable thyroid nodules 1–2 cm in diameter

Purpose

To investigate the ultrasonographic (US) characteristics for nonpalpable thyroid nodules 1–2 cm in diameter and to evaluate the guideline for fine needle aspiration (FNA) in terms of US findings.

Materials and methods

Between June 2005 and November 2006, FNA was performed in 919 thyroid nodules by radiologists. Of these nodules, 51 malignant nodules and 72 benign nodules were finally included. All 123 nodules were analyzed by 3 radiologists if there were the following US characteristics: marked hypoechogenecity, hypoechogenecity, isoechogenecity, hyperechogenecity, microcalcification, coarse calcification, rim calcification, spiculated margin, taller-than-wide shape, irregular shape, hypoechoic rim and honeycomb appearance. The maximum diameters of nodules and thickness of hypoechoic rim were measured. US characteristics relevant as predictors were identified using a Chi-square or Fisher's exact test and odds ratio. We compared the diagnostic efficacy of 3 US criteria for FNA indication.

Results

Microcalcification, taller-than-wide shape, marked hypoechogenecity, hypoechogenecity, coarse calcification, irregular shape and spiculated margin were significant characteristics of malignant nodules. Isoechogenecity, hypoechoic rim and honeycomb appearance was significant characteristics of benign nodules. Rim or arc calcification, hyperechogenecity and thickness of hypoechoic rim were insignificant. Among 3 US criteria for FNA indication, NFI showed the highest diagnostic efficacy, 98.0% in sensitivity, 75.0% in specificity and 150.0 in odds ratio.

Conclusion

As for nonpalpable thyroid nodules 1–2 cm in diameter, US characteristics are useful for differentiating between malignant and benign nodules. Malignant US characteristics and honeycombing appearance have significant value in selecting nodules for biopsy and reducing the frequency of the FNA procedure.     

The value of virtual touch tissue image (VTI) and virtual touch tissue quantification (VTQ) in the differential diagnosis of thyroid nodules

Objectives

To explore the value of virtual touch tissue image (VTI) and virtual touch tissue quantification (VTQ) in the differential diagnosis of thyroid nodules.

Methods

One-hundred and seven patients with 113 thyroid nodules were performed conventional ultrasound and acoustic radiation force impulse (ARFI) elastography. The stiffness of the nodules on virtual touch tissue image (VTI) was graded, and the area ratios (AR) of nodules on VTI images versus on B-mode images were calculated. Shear wave velocity (SWV) within the thyroid nodules were measured using virtual touch tissue quantification (VTQ) technique. The pathological diagnosis as the gold standard draws the receiver-operating characteristic curve (ROC) to find the cut-off point of VTI grades, AR and SWV to predict thyroid cancer.

Results

The difference in VTI grades of malignant and benign nodules was statistically significant (P < 0.05), as well as in AR and SWV. There was no significant difference in the AR of nodules or the SWV of nodules in benign group or in malignant group. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of VTI grades, AR, and SWV in the differential diagnosis of thyroid nodules were calculated. There was no significant difference in diagnostic accuracy among the three methods.

Conclusion

VTI grades, AR of nodules on VTI images versus on B-mode images and SWV within the nodules can help the differential diagnosis of thyroid nodules.     

A threshold value in Shear Wave elastography to rule out malignant thyroid nodules: A reality?

Objectives

To evaluate hability of a threshold value in ShearWave™ elastography to rule out malignant thyroid nodules while studying its pertinence in association with morphological signs.

Equipment and methods

148 patients (110 women and 38 men; 52.5 y.o. 15.8) referred for surgery of thyroid nodules underwent standard ultrasound as well as elastography. Characteristics of the morphological signs and maximum elastographic index were calculated in relation to histology. Association of morphological signs alone and then of elastography was also evaluated. One hundred and fifty one nodules were studied on a double-blind basis.

Results

297 nodules were studied. Thirty-five cancers were detected (11.6%). Elastographic index was higher in malignant nodules (115 kPa 60.4) than in benign nodules (41 kPa 25.8) (p < 0.001, Student's t-test). Cut off value of 66 kPa was the best to discriminate malignant nodules with a sensitivity of 80% (CI 95%, 62.5; 90.9) and a specificity of 90.5% (CI 95%, 86.1; 93.6) (p = 0.0001). Association of elastography and morphological ultrasound signs presented a sensitivity of 97% (CI 95%, 83.3; 99.8) and a negative predictive value of 99.5% (CI 95%, 95.6; 99.9). Interobserver reproducibility proved to be excellent with an interclass correlation of 0.97 (CI 95%, 0.96; 0.98) (p < 0.001).

Conclusion

The 66 kPa threshold in Shear Wave elastography is the best ultrasound sign to rule out malignant thyroid nodules. The method is simple, quantitative, reproducible and usable in the study of nodules larger than 3 cm. Progress must still be made in the study of calcified nodules and follicular tumors.     

Can real-time ultrasound elastography using the color score and strain ratio differentiate between benign and malignant solitary thyroid nodules?

Background

Solitary thyroid nodule may represent a multitude of thyroid disorders; therefore, detection of whether these nodules are benign or malignant is crucial for patient’s triage.

Objective

To evaluate the diagnostic performance of the latest generation of real-time ultrasound elastography (USE) in differentiation between benign and malignant solitary thyroid nodules.

Materials and methods

Thirty consecutive patients who were referred for surgical treatment were prospectively examined by real-time USE. Tissue stiffness on real-time USE was determined with light compression using the standard elastography color scoring system according to Rago criteria ranging from 1 (low stiffness over the entire nodule) to 5 (high stiffness over the entire nodule and surrounding tissue). The strain ratio (normal tissue to lesion strain ratio) was calculated. The histopathological examination of these resected nodules was used as the diagnostic standard of reference.

Results

Scores of 1 and 2 with Rago criteria were highly significant seen in benign nodules, whereas, scores of 4 and 5 with Rago criteria were highly significant seen in malignant nodules (p < 0.001) with a sensitivity, specificity and diagnostic accuracy of 78.6%, 78.9% and 78.8% respectively. Additionally, the best strain ratio cut-off value for discrimination between benign and malignant nodules by using receiver operating characteristic analysis was 2.20 (area under the curve of 0.861; p value <0.001) with a consequential sensitivity, specificity and diagnostic accuracy of 85.7%, 90.5% and 88.6% respectively.

Conclusion

Both the color score and the strain ratio are higher in malignant solitary thyroid nodules than those in benign ones. Consequently, real-time USE can be used for the differentiation of benign and malignant solitary thyroid nodules. Eventually, this reduces the number of superfluous surgical procedures on benign thyroid nodules.     

Distinguishing benign from malignant thyroid nodules using thyroid ultrasonography: utility of adding superb microvascular imaging and elastography

Objective

Thyroid nodules are common; however, malignancy is less than 7%. Therefore, additional techniques such as Doppler ultrasonography or elastography are used to improve diagnostic performance of conventional ultrasonography. We want to prospectively investigate the use of additional superb microvascular imaging (SMI) and strain elastography to B-mode ultrasound in thyroid nodules in distinguishing benign from malignant thyroid nodules.

Methods

We analyzed 52 thyroid nodules (malignant = 26, benign = 26) and reviewers scored the likelihood of malignancy for three data sets (i.e., B-mode ultrasonography alone, B-mode ultrasonography + SMI, and B-mode ultrasonography + strain elastography). The area under the receiver-operating characteristic curve (Az) values, sensitivities, and specificities were compared.

Results

A comparison of the data sets revealed that area under the receiver-operating characteristic curve values were similar without statistical difference. However, on comparing sensitivity and specificity based on the management decision of whether to conduct fine-needle aspiration (FNA) after combining information from all three types of imaging (B-mode ultrasonography + SMI + strain elastography), specificity was significantly higher for the combined technique (34.6%) than for B-mode ultrasonography alone (11.5%), without decrease in sensitivity (P = 0.032).

Conclusion

Additional use of SMI and strain elastography could potentially lead to increase in specificity in thyroid ultrasonography.

     

Size discrepancy between sonographic and pathological evaluation of solitary papillary thyroid carcinoma

Background

Sonographic size of suspicious thyroid lesions is an essential parameter in the evaluation of thyroid nodules, determining the need for needle biopsy and has impact on the extent of surgery. Limited data is available on the correlation between the size of the thyroid nodule on sonography and the actual size measured during histological examination. The aim of the present study was to compare these two modalities and to discuss the potential clinical implications of the findings in the study population.

Methods

The database of Rabin Medical Center was reviewed for all patients with histologically proven papillary carcinoma of the thyroid treated by thyroid surgery between 2005 and 2010.

Results

292 patients with papillary thyroid carcinoma were included. The mean sonographic size of the nodule was 2.19 ± 1.15 cm. The mean pathological diameter was 1.69 ± 1.09 cm. Discrepancies between tumor histological diameter and the sonographically measurement were more prominent in tumors larger than 1.5 cm. Nonetheless, 18.8% of thyroid nodules that were measured by US as larger than 1 cm, were found to be smaller than 1 cm on final pathology. Similarly, 7.2% of nodules evaluated by sonography were determined as being larger than 4 cm, while their definitive size was smaller than 4 cm.

Conclusions

We noted a significant discrepancy between the preoperative sonographic and the pathologic size measurements for papillary thyroid carcinoma. The sonographic evaluation misclassifies both patients with small and large thyroid tumors, and consequently exposes them to unnecessary workup and more extensive operation. This discrepancy between the ultrasound findings and actual tumor size should be taken into account in clinical practice and help guide the evaluation and treatment of patients with thyroid nodules.     

Role of quantitative diffusion-weighted MRI and H MR spectroscopy in distinguishing between benign and malignant thyroid nodules

Background and purpose

The imaging characterization of thyroid nodules is mandatory to exclude malignancy. The purpose of this study is to evaluate the role of quantitative diffusion MRI and ¹H MR spectroscopy in differentiation between benign and malignant Thyroid nodules.

Methods

From February 2012 to May 2013, prospective study was conducted on 25 patients with 41 thyroid nodules (11 males, 14 females, age range, 16–74 years with mean 45.3 years) collected from wards and clinics of Internal Medicine and General Surgery Departments, 20 healthy individuals as control cases were included in the study. 1.5-T ¹H-MR spectroscopy (at echo-times (TE) 144 and 35 ms) and diffusion-weighted imaging (b value 0, 250 and 1000 s/mm²) were performed and the results were correlated with histopathological results.

Results

The mean ADC of the malignant thyroid nodules (13 nodules) was 0.59 ± 0.24 × 10⁻³ mm²/s while that of the benign thyroid nodules (28 nodules) was 1.78 ± 0.21 × 10⁻³ mm²/s (p value <0.0001).Choline is present in all malignant nodules (13 nodules) and two benign nodules (mild elevation) while absent in 26 other benign nodules. Choline/creatine ratio in malignant nodules ranged from 1.3 to 5.4, while in two benign nodules it was 0.9 and 1.1.The sensitivity, specificity, PPV, NPV and overall accuracy of diffusion and MRS in differentiating benign from malignant thyroid nodules were 100%, 93%, 96%, 100% and 79%, respectively.

Conclusion

MRS and diffusion WI are useful noninvasive diagnostic modalities in differentiation between benign and malignant thyroid nodules.     

Comparison analysis between conventional ultrasonography and ultrasound elastography of thyroid nodules

Objective

To compare the effectiveness of conventional ultrasonography and ultrasound elastography in differential diagnosis of thyroid nodular diseases.

Methods

244 patients with 291 thyroid nodules were examined by ultrasonography and ultrasound elastography respectively; the examination results were compared against pathological findings to determine the effectiveness of these two examination methods.

Results

The sensitivity and positive predictive value of conventional ultrasonography is higher than those of ultrasound elastography, but its specificity, accuracy, and negative predictive value is lower than those of the later.

Conclusions

Ultrasound elastography is superior to conventional ultrasonography in differential diagnosis of thyroid nodules. However, ultrasonography is the basis of examination; only on this basis, an additional ultrasound elastography examination could greatly improve the diagnostic rate of thyroid nodular diseases.     

The value of acoustic radiation force impulse (ARFI) in the differential diagnosis of thyroid nodules

Objectives

The aim of this study was to investigate the value of shear wave velocity value (SWV) and shear wave velocity ratio (SWR) in differentiating between malignant and benign thyroid nodules using virtual touch tissue quantification (VTQ) of acoustic radiation force impulse (ARFI) technology.

Methods

The SWV and SWR were analyzed in 155 thyroid nodules in 155 patients (93 benign and 62 malignant) and eighty normal thyroid glands. The diagnostic performance of SWV and SWR were compared.

Results

The mean value of SWV of malignant nodules differed significantly from those of the benign nodules (6.34 ± 2.58 m/s vs. 2.15 ± 0.59 m/s, P < 0.05) and the normal thyroid (1.96 ± 0.31 m/s, P < 0.05). There was no statistically significant difference between the mean value of SWV of benign nodules and normal thyroid (P > 0.05). The mean value of SWR of malignant nodules differed significantly from those of the benign nodules (2.99 ± 1.45 vs. 1.07 ± 0.34, P < 0.05). The sensitivity, specificity, positive predictive values, negative predictive values and accuracy of SWV in differentiating between malignant and benign nodules were 96.80%, 95.70%, 93.75%, 97.80% and 96.13% respectively based on the cutoff point as 2.84 m/s. Those of SWR were 91.90%, 81.70%, 77.03%, 93.83% and 85.83% based on the cutoff point as 1.32. The diagnostic accuracy rate of SWV was statistically higher than that of SWR (P < 0.05).

Conclusion

VTQ of ARFI technology provides the quantitative information of thyroid tissue elasticity and has high accuracy rate in differentiating between malignant and benign nodules. It is a useful complement for conventional ultrasonography.     

Neck ultrasonography as preoperative localization of primary hyperparathyroidism with an additional role of detecting thyroid malignancy

Objective

To evaluate and compare the diagnostic performances of high-resolution ultrasonography and ^99mTc-sestamibi scintigraphy for the preoperative localization of abnormal parathyroid glands and to evaluate the ability of US for additional diagnostic roles in detecting thyroid malignancy in patients with pHPT.

Materials and methods

Preoperative localization images of 115 parathyroid adenomas from high-resolution ultrasonography (US) and ^99mTc-sestamibi scintigraphy (SS) were studied from 105 patients, who had undergone parathyroidectomy. Sensitivity, accuracy, and positive predictive value were calculated for the identification of adenomas in lesions and patients for both US and SS, respectively, and US and SS diagnostic performances were compared using generalized estimating equation.

Results

Preoperative imaging by both modalities localized 105 (93.8%) of the 112 parathyroid lesions confirmed at surgery and histology. Sensitivity, accuracy, and positive predictive value were 93.1% and 92.2%, 90.4% and 89.5%, and 96.9% and 96.9% by US and SS, respectively, without any statistically significant differences (P = 0.796, 0.796, 0.879). US found incidental thyroid nodules in 47 patients (47/107, 43.9%), and 7 patients (7/107, 6.5%) were confirmed to have malignancy based on pathology results (all had papillary thyroid carcinoma).

Conclusion

Neck ultrasonography and ^99mTc-sestamibi scintigraphy are complementary methods of the preoperative localization of parathyroid adenomas. Neck ultrasounds add an additional thyroid gland evaluation, and can be useful in the detection of incidental thyroid gland lesions, especially malignant nodules.     

Role of diffusion-weighted imaging with ADC mapping and in vivo H-MR spectroscopy in thyroid nodules

Purpose

To evaluate the role of the combined techniques of apparent diffusion coefficient (ADC) generated from diffusion-weighted magnetic resonance (MR) imaging (DWI) and metabolite spectrum acquired by magnetic resonance spectroscopy (MRS) in differentiating benign from malignant thyroid nodules.

Materials and methods

Thirty-seven patients with 56 thyroid nodules were evaluated with conventional MRI (T1- & T2-WI), DWI (b value 0.500 s/mm²; ADC values were calculated for the thyroid nodules), and MRS (for the presence or absence of choline peak). The ADC values and MRS findings were correlated with the histopathological results.

Results

The mean ADC of the malignant thyroid nodules (0.89 ± 0.27 × 10⁻³ mm²/s) was significantly lower than that of the mean ADC of the benign thyroid nodules (1.85 ± 0.24 × 10⁻³ mm²/s) (p value <0.0001). ADC value of 1.5 × 10⁻³ mm²/s was used as a cut-off value for differentiation benign from malignant thyroid nodules. The sensitivity, specificity, PPV&NPV of DWI in differentiating benign from malignant thyroid nodules were 94%, 95%, 94% & 95%, respectively (Kappa test 0.84, p value <0.0001), whereas they were 94.7%, 89.2%, 81.8% & 97.1% (Kappa test 0.8, p value <0.0001) with MRS, and 96%, 100%, 100% & 97% (Kappa test 0.96, p value <0.0001) with both DWI and MRS.

Conclusion

Both DWI and MRS are useful diagnostic modalities for characterization and differentiation between benign and malignant thyroid nodules. Our preliminary results showed that combination of DWI with calculated ADC values and metabolite spectrum acquired by MRS add more information to MRI and should be considered as an additional and complementary tool to conventional MRI for differentiating benign from malignant thyroid nodules.     

Comparison of muscle-to-nodule and parenchyma-to-nodule strain ratios in the differentiation of benign and malignant thyroid nodules: Which one should we use?

Objective

The aim of this study is to investigate the diagnostic accuracy of muscle-to-nodule strain ratio (MNSR) in the differentiation of benign and malignant thyroid nodules and to see if there was a difference between MNSR and parenchyma-to-nodule strain ratios (PNSR) in diagnosis.

Methods

A total of 106 consecutive patients (88 women and 18 men; age range 19–79 years) with thyroid nodules were prospectively examined using ultrasound and sonoelastography before the fine-needle aspiration biopsy. The mean MNSR and PNSR were calculated for each nodule and the elasticity score was determined according to four-point scoring system.

Results

According to the four-point scoring system, 44 of the 83 benign nodules had a score of one or two while 22 of the 23 malignant nodules had a score of three or four (p < 0.001). Using ROC analysis, the best cutoff point for MNSR 1.85 and for PNSR 3.14 was calculated. The sensitivity and specificity for the MNSR were 95.6%, 92.8%, respectively; for the PNSR were 95.6%, 93.4%, respectively, when the best cutoff points were used (p < 0.001). The κ value for the PNSR and MNSR methods was 0.87, which indicated an almost perfect agreement (p < 0.001).

Conclusions

Sonoelastography has a high diagnostic accuracy in the differentiation of benign and malignant thyroid nodules. There was no significant difference between MNSR and PNSR in the differentiation of benign and malignant thyroid nodules. Therefore, we think that MNSR could safely be used in situations where PNSR could not be used.     

The value of strain ratio in differential diagnosis of thyroid solid nodules

Objective

To assess the clinical value of strain ratio in differentiating thyroid solid nodules and explore its distribution characters based on pathological results.

Materials and methods

The study was approved by the ethic committee and the informed consents were signed. Ninety nine solid thyroid nodules (67 benign and 32 malignant) from 71 female (mean age 46.3 ± 9.8 years) and 28 male (mean age 54.9 ± 11.7 years) patients were evaluated. Five radiologists evaluated the nodules based on a four-degree elastography score system. Strain ratio was calculated on-line. Diagnostic performances of the two evaluations were compared using Receiver Operating Characteristic (ROC) curves. Values of different pathological nodules were compared by one-way ANOVA.

Results

Areas under the ROC curve (AUC) of the five readers were 0.82, 0.81, 0.79, 0.73 and 0.83, respectively. The AUC of strain ratio evaluation was higher (0.88 vs. 0.79, p < 0.001) than that of the ES score evaluation. Best cut-off points of the two evaluations were 3.5 (82% sensitivity, 72% specificity) and 4.225 (81% sensitivity, 83% specificity), respectively. Both the ES score and strain ratio were higher for malignant nodules than that for benign ones (p < 0.001).

Conclusions

Strain ratio was a useful index in differential diagnosis of thyroid solid nodules. It can provide quantitative information on thyroid nodule characterization and improve diagnostic confidence. The best cut-off point for benign and malignant nodules was 4.2.     

Ultrasound guided percutaneous microwave ablation of benign thyroid nodules: Safety and imaging follow-up in 222 patients

Objective

Microwave ablation is a minimally invasive technique that has been used to treat benign and malignant tumors of liver, lung and kidney. Towards thyroid nodules, only a few cases are reported so far. The aim of the study was to investigate the effectiveness and safety of ultrasound-guided percutaneous microwave ablation in the treatment of benign thyroid nodules with a large sample.

Materials and methods

A total of 477 benign thyroid nodules in 222 patients underwent microwave ablation in our department from July 2009 to March 2012. Microwave ablation was carried out using microwave antenna (16G) under local anesthesia. Nodule volume, thyroid function and clinical symptoms were evaluated before treatment and at 1, 3, more than 6 months. The study was ethics committee approved and written informed consents were obtained from all patients.

Results

All thyroid nodules significantly decreased in size after microwave ablation. A 6-month follow-up was achieved in 254 of 477 nodules, and the mean decrease in the volume of thyroid nodules was from 2.13 ± 4.42 ml to 0.45 ± 0.90 ml, with a mean percent decrease of 0.65 ± 0.65. A volume-reduction ratio greater than 50% was observed in 82.3% (209/254) of index nodules, and 30.7% (78/254) of index nodules disappeared 6-month after the ablation. The treatment was well tolerated and no major complications were observed except pain and transient voice changes.

Conclusions

Microwave ablation seems to be a safe and effective technique for the treatment of benign thyroid nodules. Further prospective randomized studies are needed to define the role of the procedure in the treatment of thyroid nodules.     

Prospective comparative evaluation of quantitative-elastosonography (Q-elastography) and contrast-enhanced ultrasound for the evaluation of thyroid nodules: Preliminary experience

Purpose

To assess the effectiveness of semiquantitative elastosonography (Q-elastography) compared with contrast-enhanced ultrasound (CEUS) in differentiating the nature of thyroid nodules.

Methods and materials

Forty-eight consecutive patients (35 males, 13 females, range: 34–69 years, mean: 49.4 years), candidate to surgery, previously detected at color-Doppler ultrasound (CDUS), were prospectively examined with elastosonography with dedicated semiquantitative software (Q-Elastography, Toshiba XG) and CEUS (Technos Mylab 70 Gold X, and Toshiba XG) before surgery. CEUS and elastosonography were evaluated by two investigators in consensus. Comparison between the CEUS pattern and elastonographic strain ratio observed and expected frequencies for the diagnoses was evaluated with χ² test or with Fisher exact test.

Results

Fifty-three nodules (19 papillary carcinoma, 32 hyperplasia, and 2 follicular adenoma) in 48 patients were available for analysis. Regarding echogenicity score, sensitivity, specificity, PPV and NPV of conventional US were 81%, 50%, 56%, 77%; according to Q-elastography, sensitivity, specificity, PPV and NPV were 95%, 88%, 97% and 91% respectively; whereas concerning CEUS, sensitivity specificity PPV and NPV were 79%, 91%, 83% and 89% respectively. Both CEUS and Q-elastography were more specific than US (p < 0.01), with not statistical significant difference with regard to sensitivity.

Conclusions

The results of the present study suggest that Q-elastography is a valuable tool in the characterization of thyroid nodules and it seems to be more sensitive than CEUS.