|Year : 2021 | Volume
| Issue : 1 | Page : 191-197
Role of sonoelastography and thyroid imaging reporting and data system in assessment of thyroid nodules
Eman M.S.A Elewa1, Rawhia T Hassan2, Talal A Amer1
1 Department of Radio-Diagnosis, El Simbellaween Hospital, El-Dakahlia, Egypt
2 Department of Radio-Diagnosis, Faculty of Medicine for Girls, Al Azhar University, Cairo, Egypt
|Date of Submission||11-Oct-2020|
|Date of Decision||15-Oct-2020|
|Date of Acceptance||05-Nov-2020|
|Date of Web Publication||21-Apr-2021|
MSc Eman M.S.A Elewa
Department of Radio-Diagnosis, El Simbellaween Hospital, El-Dakahlia
Source of Support: None, Conflict of Interest: None
Background Thyroid nodules are very common and may be observed at ultrasound (US) in 50% of adult population. US elastography is a noninvasive technique for evaluating thyroid nodules to decrease the number of tissue biopsies. Thyroid imaging reporting and data system (TIRADS) is the assessment of risk stratification of thyroid nodules using a score.
Patients and methods This cross-sectional study was carried out on 100 patients with 146 thyroid nodules. The study was conducted in the period from October 2018 to October 2020 at the Radiology Department and approved by the Ethics Committee, and all patients gave their informed consent before inclusion in the study. Results were collected and then analyzed using a specialized computer statistical program.
Results We found 124 (84.9%) benign nodules and 22 (15.1%) malignant nodules. The accuracy of elastography color score in detection of malignancy was found to be 95.1%, 89.7% for strain ratio, and 88.4% for TIRADS.
Conclusion Adding elastography examination and TIRADS score to the routine thyroid US will be of high diagnostic value in detection of malignancy.
Keywords: real-time elastography, sonoelastography, thyroid nodules, thyroid imaging reporting and data system
|How to cite this article:|
Elewa EM, Hassan RT, Amer TA. Role of sonoelastography and thyroid imaging reporting and data system in assessment of thyroid nodules. Sci J Al-Azhar Med Fac Girls 2021;5:191-7
|How to cite this URL:|
Elewa EM, Hassan RT, Amer TA. Role of sonoelastography and thyroid imaging reporting and data system in assessment of thyroid nodules. Sci J Al-Azhar Med Fac Girls [serial online] 2021 [cited 2022 Jun 26];5:191-7. Available from: http://www.sjamf.eg.net/text.asp?2021/5/1/191/314042
| Introduction|| |
The prevalence of thyroid nodules in population has increased around the world. Recently, the estimated incidence of thyroid nodules is nearly 19–67%, and ∼5–15% of these nodules are found to be malignant . High-resolution ultrasound (US) is the most sensitive diagnostic imaging technique for the detection of thyroid nodules . It is necessary to standardize terminology and create guidelines to categorize thyroid nodules according to their malignant potential for effective management . Several different thyroid imaging reporting and data system (TIRADS) classifications and recommendations have been proposed .
Ultrasound elastography (USE) is a newly developed dynamic technique that uses US to provide an estimate of tissue stiffness by measuring the degree of distortion under the application of an external force like palpation in the assessment of the thyroid during physical examination .
| Patients and methods|| |
A written informed consent was taken from all participants after proper explanation of the study. This study was conducted in the Oncology Center of Mansoura university hospitals, Egypt, during the period from October 2018 to October 2020 and approved by the Ethics Committee. It was carried out on 100 patients presented with thyroid nodules. Data including age, sex, complaint, and marital status were reported. All patients underwent thyroid US examination, Doppler study, and sonoelastography. All patients with clinically palpable single or multiple thyroid nodules and diagnosed by high-resolution superficial neck US were included in this study. We excluded all patients with thyroid nodules less than 5 mm. or had previous biopsy less than 3 months ago.
The patient lied in a supine position with his neck slightly extended. Adequate amount of US gel was applied to the patient’s neck. We used 15-MHz linear array transducer (Toshiba Aplio 500 system, Canon Medical Systems Corporation, Otawara, Tochigi, Japan). The probe was positioned slightly in contact with the skin. The US examination started with B-mode imaging and Doppler study of each nodule. Each nodule was categorized to one of TIRADS classification.
Elastographic evaluation of thyroid nodules
Elastography evaluation is performed [elastogram and strain ratio (SR)]. The region of interest was centered on the lesion, including sufficient surrounding normal thyroid tissue. The patients were asked to avoid swallowing and hold their breath during the examination to minimize the motion of the thyroid gland. Strong initial compression is avoided. The appropriate pressure was defined as a pressure which can sustain the number of the scale between 2 and 4 for at least 3 s. Compression with light pressure followed by decompression is repeated until a stable image is obtained from which we assessed the elastography color score and the SR.
This is a cross-sectional study.
Data were collected and revised and then analyzed using statistical package for the social sciences (IBM SPSS), version 21.
| Results|| |
Our study included 100 patients with 146 thyroid nodules. The patients’ age ranged from 20 to 78 years, with mean±SD age of 43.9±11.47 years. There was a female predominance, as 91 (91%) patients of the studied patients were females and nine (9%) patients were males. On fine-needle aspiration cytology, 84.9% were benign (benign follicular thyroid lesion 48.6%, colloid nodular goiter 29.5%, focal Hashimoto thyroiditis 1.4%, and Hurthle cell adenoma 2.7%) and 15.1% were malignant (papillary thyroid carcinoma 8.2%, follicular carcinoma 3.4%, NHL 1.4%, anaplastic carcinoma 1.4%, and medullary carcinoma 0.7%). The US criteria of the studied nodules are shown in [Table 1].
Most of the nodules were solid (84.2%), isoechoic (75.3%), wider than tall (97.3%), had smooth margin (56.8%), had no calcifications (77.4%), had peripheral vascularity (79.5%) and associated with benign lymph nodes (98.6%).
From the previous US criteria, TIRADS classification included five categories. Most of the nodules had T3 category (69.2%), whereas only 1.4% of nodules had T1 category. Most of the malignant nodules (20 of 22) had T4 and T5 (90.9%). Most of the benign nodules (109 of 124) had T1, T2, and T3 (87.9%), with accuracy to detect malignancy of ∼88.4%, as shown in [Table 2].
|Table 2 Validity of thyroid imaging reporting and data system in detection of malignant nodules compared with fine-needle aspiration cytology|
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About elastography color score, most of the malignant nodules (16 of 22) had scores 3 and 4 (72.7%), whereas most of the benign nodules (121 of 124) had scores 1 and 2 (97.5%), with accuracy to detect malignancy reaching 95.1%, as shown in [Table 3].
|Table 3 Validity of elastography score in detection of malignant nodules compared with fine-needle aspiration cytology|
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Regarding the SR, the area under receiver operating characteristic curve for SR in the prediction of malignant nodules is 0.93 (95% confidence interval: 0.88–0.98), and our cutoff point to differentiate between malignant and benign nodules was 2.90. Above it, it will be malignant, with accuracy in detection of malignancy reaching 89.7%, as shown in [Table 4] and [Figure 1].
|Table 4 Receiver operating characteristic curve for diagnostic accuracy of strain ratio in prediction of malignant nodules|
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|Figure 1 ROC for diagnostic accuracy of SR in prediction of malignant nodules. ROC, receiver operating characteristic; SR, strain ratio.|
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[Table 5] compares between the accuracy of conventional US (including TIRADS) and elastography (color score and SR) in detection of malignancy ([Figure 2],[Figure 3],[Figure 4]).
|Table 5 Comparison of diagnostic performance in distinguishing benign from malignant thyroid nodules by using conventional ultrasound and elastography grade|
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|Figure 2 A 27-year-old female patient presented with neck swelling. (a) 2D US image revealed oval wider than tall smooth solid right lobe mass. No calcifications (TIRADS 3). (b) Doppler study revealed messy vascularity. (c) Elastography color score 1, SR=0.93. FNAC revealed: benign follicular thyroid lesion (Bethesda II). FNAC, fine-needle aspiration cytology; SR, strain ratio; TIRADS, thyroid imaging reporting and data system; US, ultrasound.|
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|Figure 3 A 24-year-old female patient presented with neck swelling and weight loss. (a) 2D US examination revealed isthmic mass, complex isoechoic solid part, and wider than tall with microcalcifications (TIRADS 4). (b) Doppler study revealed moderate central vascularity. (c) Deep cervical LN resembling the primary thyroid lesion. (d) Elastography color score 3. SR=3.6. FNAC revealed: papillary thyroid carcinoma (Bethesda V). FNAC, fine-needle aspiration cytology; SR, strain ratio; TIRADS, thyroid imaging reporting and data system; US, ultrasound.|
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|Figure 4 A female patient presented with neck swelling. (a) 2D US image revealed right lobe mass, complex isoechoic solid part, and wider than tall mass with microcalcifications (TIRADS 4). (b) Doppler study revealed mild peripheral vascularity. (c) Elastography color score 2. SR=1.79. FNAC revealed: colloid nodular goiter. FNAC, fine-needle aspiration cytology; SR, strain ratio; TIRADS, thyroid imaging reporting and data system; US, ultrasound.|
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| Discussion|| |
The prevalence of thyroid nodules in population is increased around the world. Recently, the estimated incidence of thyroid nodules is nearly 19–67%, and ∼5–15% of these nodules are found to be malignant .
Thyroid US is a key examination for the management of thyroid nodules. Thyroid US is easily accessible, noninvasive, cost-effective, and is a mandatory step in the diagnosis of thyroid nodules .
Several professional societies and groups of investigators have proposed methods to guide US practitioners in recommending FNA on the basis of US features. Some of these systems were termed TIRADS because they were modeled on the ACR’s BIRADS, which has been widely accepted in breast imaging . TIRADS is also necessary to standardize terminology and create guidelines to categorize thyroid nodules according to their malignant potential for effective management .
Real-time elastography is a promising imaging technique that reveals the physical properties of soft tissue by characterizing the difference in elasticity between the region of interest and the surrounding normal soft tissue using manual compression and deformation of the tissue .
We found that US features such as irregular and lobulated margin of the nodule, taller than wide shape, and hypoechogenicity were highly suspicious criteria of malignancy, as irregular and lobulated margins of the nodule are found in ∼45.5 and 22.7% of all malignant nodules, respectively, with overall percentage of ∼68.2%, and hypoechogenicity is found in 72.7% of malignant nodules. All taller-than-wide nodules were malignant. Eltyib et al. ; Abdelrahman et al. ; Habib et al. ; and Esfahanian et al.  in their studies found that hypoechogenicity, irregular margin, taller-than-wide shape, and punctate microcalcifications were the US patterns most predictive of malignancy. This was in agreement with our study, except for microcalcifications, as we found that most of the malignant nodules showed no calcifications (54.5%), whereas 13.6% of malignant nodules showed microcalcifications.
Regarding the TIRADS of the examined nodules in our study, we found that two nodules had TIRADS I (1.4%), eight nodules had TIRADS II (5.5%), 101 nodules had TIRADS III (69.2%), 27 nodules had TIRADS IV (18.4%), and eight nodules had TIRADS V (5.5%). TIRADS I, II, and III were seen in two of 22 malignant nodules (9.1%) and 109 (77.8%) of 124 benign nodules, whereas TIRADS IV and V were seen in 20 (90.9%) of 22 malignant nodules and 15 (12.2%) of 124 benign nodules.
TIRADS scoring system increases the US sensitivity and specificity to 90.9 and 87.9%, respectively, with positive predictive value (PPV), negative predictive value (NPV), and accuracy of 57.1, 98.2, and 88.4%, respectively. Yang et al. , in their study found that the sensitivity, specificity, PPV, NPV, and accuracy of conventional US were 82, 69, 56.9, 88.5, and 73.3%, respectively.
Elastography of the examined nodules in our study included two parts: the first was the color score, and we use the Asteria scoring system (four scale scoring system), and the second was measurement of SR of the examined nodule.
In our study, we found that scores 1 and 2 were detected in 121 (97.5%) of 124 benign nodules and six (27.2%) of 22 malignant nodules. Overall, two nodules had the characteristic BGR of cystic lesions, whereas scores 3 and 4 were detected in 16 (72.7%) of 22 malignant nodules and one (0.8%) of 124 benign nodules, with overall sensitivity of 72.7%, specificity of 99.2%, PPV of 94.1%, NPV of 95.3%, and accuracy of 95.1%. Habib et al. , found that elastogram score 2 was detected in 100% of benign nodules and 0% of malignant nodules, score 3 was detected in 54.5% of benign nodules and 45.6% of malignant nodules, score 4 was detected in 12.5% of benign nodules and 87.5% of malignant nodules, whereas score 5 was seen only in malignant nodules, with sensitivity, specificity, PPV, NPV, and accuracy of 91, 72, 83, 92, and 91%, respectively.
Regarding the SR, in our study, we found that the best SR cutoff value to differentiate benign from malignant nodules was 2.90, with 86.4% sensitivity, 90.3% specificity, PPV of about 61.3%, NPV of about 97.4%, and accuracy of about 89.7%. This was quiet similar to the study done by Refaat et al. , which showed that the best SR cutoff value for discrimination between benign and malignant nodules was 2.20 with sensitivity, specificity, and diagnostic accuracy of 85.7, 90.5, and 88.6%, respectively. However, Habib et al. , found that the optimal cutoff value was 1.6, with sensitivity of about 89%, specificity of about 70%, PPV of about 78%, NPV of about 90%, and accuracy of about 86%. Xing et al. , found that the optimal cutoff point was 3.79, with 97.8% sensitivity and 85.7% specificity.
Finally, in our study, the sensitivity, specificity, PPV, NPV, and accuracy for TIRADS were 90.9, 87.9, 57.1, 98.2, and 88.4%, respectively, whereas the sensitivity, specificity, PPV, NPV, and accuracy for USE color score were 72.7, 99.2, 94.1, 95.3, and 95.1%, respectively, and the sensitivity, specificity, PPV, NPV, and accuracy for SR were 86.4, 90.3, 61.3, 97.4, and 89.7%, respectively, at a 2.90 cutoff value.
| Conclusion|| |
The combination of elastography with TIRADS scoring system can provide relatively high accuracy in differentiating benign from malignant nodules. USE can be routinely used in thyroid US scans to select cases for fine-needle aspiration cytology, decrease the number of unnecessary biopsies, and consequently decrease the hazards and costs.
Financial support and sponsorship
Conflicts of interest
There was no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]