1. Journal Club 2007.9.27 Elastography: New Development in Ultrasound for Predicting Malignancy in Thyroid Nodules T. Rago, F. Santini, M. Scutari, A. Pinchera, and P. Vitti Department of Endocrinology, University of Pisa, 56124 Pisa, Italy The Journal of Clinical Endocrinology & Metabolism 2007; 92(8): 2917- 2922

2. Background Elastography is a newly developed dynamic technique that uses ultrasound (US) to provide an estimation of tissue stiffness by measuring the degree of distortion under the application of an external force. US elastography has been applied to differentiate malignancy from benign leisions.

3. Individual features No. 195237271809427 Sensibility 58.0%87.1%61.3%77.5%74.2%29.0% Specificity 52.3%43.4%32.0%85.0%80.8%95.0% Predictive value for malignancy 10.0%11.4%7.0%30.0%24.0%33.0% In conjunction with hypoechoic appearance No. 119136687322 Sensibility 45.1%54.8%74.2%61.0%26.0% Specificity 71.7%68.0%87.8%85.5%96.3% Predictive value for malignancy 11.7%12.5%39.0%26.0%36.0% Solitary nodule Hypoechoi c nodule Nodule > 10 mm Blurred margins Intranodular vascularization Microcalci fications Sensitivity, specificity, and predictive values of US and CFD features The Journal of Clinical Endocrinology & Metabolism Vol. 87, No. 5 1941-1946 Risk of Malignancy in Nonpalpable Thyroid Nodules: Predictive Value of Ultrasound and Color-Doppler Features

4. Patients This study included 92 consecutive patients with a single thyroid nodule who underwent surgery for compressive symptoms or suspicion of malignancy on fine needle aspiration cytology. Tissue stiffness on US elastography was scored from one (greatest elastic strain) to five (no strain).

5. Score 1Elasticity in the whole nodule 2Elasticity in a large part of the nodule 3Elasticity only at the peripheral part of the nodule 4No elasticity in the nodule 5No elasticity in the nodule and in the posterior shadowing TABLE 1. Elasticity score (32 )

6. Elastography におけるパターン分類 （ JTEC: Japan Thyroid Elastography Conference) Pattern 1 : 内部が均一な Green の染まる Pattern 2 : 腫瘍辺縁が不規則に Blue に抜ける Pattern 3 : 腫瘍内部が Blue と Red の混在 Pattern 4 : 腫瘍全体が Blue に表示

7. F IG. 1. Thyroid nodule images obtained on US elastography with elasticity score 1 (A) and conventional US (B).

8. F IG. 2. Thyroid nodule images obtained on US elastography with elasticity score 5 (A) and conventional US (B).

9. Results Histology Of 92 cases, 31 (34%) had a final diagnosis of malignancy. 28 papillary carcinomas (18 classic variant, seven follicular variant, three tall cell variant) two minimally invasive follicular carcinoma one medullary carcinoma Of 92 nodules, 61 (66%) were benign 48 follicular adenomas 11 hyperplastic nodules two oxyphillic adenomas

10. BN (n = 61) CA (n = 31) P value Sensitivity (%) Specificity (%) Hypoechogenicity0.0001 81 62 Present2325 Absent386 Halo sign<0.00016182 Present5012 Absent1119 Spot microcalcifications<0.00076472 Present1720 Absent4411 Type III vascularization0.486.497 Present22 Absent5929 TABLE 2. Predictivity of thyroid US patterns in patients with thyroid nodules that resulted in benign lesions (BN) or carcinoma (CA) on histology

11. Absent halo sign/hypoechogenicity <0.0001 5893 Both present4 18 One absent5713 Absent halo sign/spot microcalcifications <0.0001 6195 Both present 319 One absent5812 Hypoechogenicity/spot microcalcifications <0.0001 5290 Both present 6 16 One absent5515 Absent halo sign/hypoechogenicity/type III vascularization 0.1 3.2100 All present 0 1 One absent 61 30 Hypoechogenicity/spot microcalcifications/type III vascularization 0.1 6.4100 All present02 One absent6129 Absent halo sign/spot microcalcifications/type III vascularization 0.1 3.2100 All present0 1 One absent 6130 BN (n = 61) CA (n = 31)P value Sensitiv ity (%) Specific ity (%) TABLE 3. Predictivity of combinations of thyroid US patterns in patients with thyroid nodules that resulted in benign lesions (BN) or carcinoma (CA) on histology

12. US Elastography score 1 41cases (all benign) score 2 8 cases (all benign) score 3 13 cases (12 benign, one carcinoma) score 4 16 cases (all carcinomas) score 5 14 cases (all carcinomas)

13. SizeScoreBN (n = 61)CA (n = 31)P valueSensitivity (%)Specificity (%) 0.8–1 cm1–3400.002100 4–505 1.1–2 cm1–3120<0.0001100 4–5016 >2 cm1–3421<0.000190100 4–509 All1–3611<0.000197100 4–5030 TABLE 4. Predictive value of US elastography in patients with thyroid nodules that resulted in benign lesions (BN) or carcinoma (CA) on histology

14. Hypoechogenicity on US 0.1 Present 14 6 Absent 11 1 Halo sign on US 0.6 Present 24 7 Absent 1 0 Spot microcalcifications on US 0.8 Present 6 2 Absent 19 5 Type III vascularization on US 0.5 Present 1 0 Absent 24 7 Score 1–3 on US elastography 251 <0.0001 Score 4–5 on US elastography 0 6 BN (n = 25)CA (n = 7)P value TABLE 5. Predictive value of US and US elastography in 32 patients with indeterminate thyroid nodule on FNA

15. Conclusions US elastography has great potential as an adjunctive tool for the diagnosis of thyroid cancer, especially in indeterminate nodules on cytology. Larger prospective studies are need to confirm these results and establish the diagnostic accuracy of this new technique.