Journal Club 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, Pisa, Italy The Journal of Clinical Endocrinology & Metabolism 2007; 92(8):

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.

Individual features No 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 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 Risk of Malignancy in Nonpalpable Thyroid Nodules: Predictive Value of Ultrasound and Color-Doppler Features

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).

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 )

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

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

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

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

BN (n = 61) CA (n = 31) P value Sensitivity (%) Specificity (%) Hypoechogenicity Present2325 Absent386 Halo sign< Present5012 Absent1119 Spot microcalcifications< Present1720 Absent4411 Type III vascularization 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

Absent halo sign/hypoechogenicity < Both present4 18 One absent5713 Absent halo sign/spot microcalcifications < Both present 319 One absent5812 Hypoechogenicity/spot microcalcifications < Both present 6 16 One absent5515 Absent halo sign/hypoechogenicity/type III vascularization All present 0 1 One absent Hypoechogenicity/spot microcalcifications/type III vascularization All present02 One absent6129 Absent halo sign/spot microcalcifications/type III vascularization 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

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)

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

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 < 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

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.