arfi imaging of thyroid nodules

HUNG THIEN NGUYEN, CUONG TUAN NGUYEN, XUAN THANH THI PHAM, HAI THANH PHAN

MEDIC MEDICAL CENTER, HCMC, VIETNAM

Acoustic radiation force impulse (ARFI)-imaging is a new technology of elastography of ultrasound enabling quantitative measurement of tissue stiffness.

The aim of the present study was to evaluate the feasibility of ARFI-measurements in the thyroid nodule.

All patients underwent conventional ultrasound, ARFI-imaging and cytological assessment.

ARFI-imaging (VTI and VTQ technologies) and eSie Touch technology were performed with 9L4 probe, using Siemens (ACUSON S2000) B-mode-ARFI combination transducer.

85 nodules were available for analysis.

67 nodules were benign on cytology,

13 nodules were malignant (papillary carcinoma),

and 5 follicular lesions.

The median velocity of ARFI-imaging in benign was of 2.06 m/s,

and malignant thyroid nodules, of 3.00 m/s, respectively.

Plot of 177 ARFI velocity measurements of 85 thyroid nodules

eSieTouch= malignant: red code (hard) homogenous or not

VTI= malignant: dark color (hard) and bigger size than B-mode image

VTI with dark color helps characterizing malignant nodule, from follicular lesions and dense colloidal cysts which have bright color on VTI.

eSie Touch of a papillary carcinoma, black (hard)

VTI of a papillary carcinoma, black (hard) and bigger size (R. panel) than B-mode image (L. panel)

eSie Touch of papillary carcinoma, inhomogenous black

VTQ of a papilary carcinoma with ARFI velocity in out of range

eSie Touch of a papillary carcinoma, color code (red= hard, purple= soft, yellow= between hard and soft). FNAC should perform at red region.

FNAC of a papillary carcinoma

FNAC of a papillary carcinoma

VTQ of a follicular lesion with ARFI velocity of 2.99 m/s (>2.3 m/s)

3 follicular lesions on Doppler and B-mode ultrasound

VTI of a follicular lesion (R. panel) with dark color (hard) and bigger size in comparison to B-mode image (L. panel)

FNAC of a follicular lesion

FNAC of a follicular lesion

FNAC of a colloidal cyst

A specificity of ARFI-imaging of 95% could be achieved using a cut-off of 3.1 m/s (area under ROC curve is 0.778).

A sensibility of ARFI-imaging of 86.49% and specificity of 59.29% could be achieved using a cut-off of 2.3 m/s (area under ROC curve is 0.778).

Area under the ROC curve: 0.778.

DISCUSSIONS

1/ Specificity important than sensibility

2/ The higher of ARFI velocity the harder of thyroid nodule

3/ Overlapping the ARFI velocities of benign and malignant nodules: combining with VTI, eSie Touch to charaterize lesion

4/ Inhomogenous structure of malignant thyroid nodules: more site measurements of VTQ based on VTI and eSie Touch and biopsy

ARFI can be performed in thyroid nodule with reliable results.

Not only base on VTQ but should refer VTI and eSie Touch technologies.

ARFI might be the reference criteria for differentiation of benign and malignant thyroid nodules.