This study evaluated the use of acoustic radiation force impulse (ARFI) imaging to measure tissue stiffness in thyroid nodules. 85 nodules underwent ARFI imaging as well as ultrasound and cytological assessment. Median ARFI velocities were higher in malignant (3.00 m/s) versus benign (2.06 m/s) nodules. Malignant nodules appeared darker and harder on ARFI imaging. A specificity of 95% was achieved using a cutoff of 3.1 m/s. ARFI imaging shows potential for differentiating benign and malignant thyroid nodules when combined with other ultrasound techniques.

1. HUNG THIEN NGUYEN, CUONG TUAN NGUYEN, XUAN THANH THI PHAM, HAI THANH
PHAN
MEDIC MEDICAL CENTER, HCMC, VIETNAM

2.  Acoustic radiation force impulse (ARFI)-imaging
is a new technology of elastography of
ultrasound enabling quantitative measurement of
tissue stiffness.
 Theaim of the present study was to evaluate the
feasibility of ARFI-measurements in the thyroid
nodule.

3.  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.

4. 85 nodules were available for analysis.
 67 nodules were benign on cytology,
 13nodules were malignant (papillary
carcinoma),
 and 5 follicular lesions.

5.  Themedian velocity of ARFI-imaging in
benign was of 2.06 m/s,
 andmalignant thyroid nodules, of 3.00
m/s, respectively.

6. Plot of 177 ARFI velocity measurements of 85 thyroid nodules

7.  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.

8. eSie Touch of a papillary carcinoma, black (hard)

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

10. eSie Touch of papillary carcinoma, inhomogenous black

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

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

14. FNAC of a papillary carcinoma

15. FNAC of a papillary carcinoma

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

17. 3 follicular lesions on Doppler and B-mode ultrasound

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

19. FNAC of a follicular lesion

20. FNAC of a follicular lesion

21. FNAC of a colloidal cyst

22. 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).

23. Area under the ROC curve: 0.778.

24. 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

25.  ARFI can be performed in thyroid nodule
with reliable results.
 Notonly 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.