Arfi

new US technique

1. ARFI

2. Acoustic radiation force impulse (ARFI) Acoustic Radiation Force Impulse (ARFI) A new sonographic technology that allow assessment of the tissue stiffness. ARFI employs high intensity acoustic beam in order to mechanically excite tissue, and monitor the tissue displacement response. No need for an external compression.

3. Acoustic radiation force impulse (ARFI) The generated wave scan from the transducer provides qualitative (imaging) and quantitative ( wave velocity values, measured in m/s) responses, by Virtual Touch Tissue Imaging and Virtual Touch Tissue Quantification , respectively.  

4. Virtual Touch Tissue Imaging ( VTI): - Series of acoustic push pulse/detection pulse sequences: - Acoustic push pulse is transmitted to compress tissue then detection pulses are used to track the amount of displacement on axis to the push pulse within the ROI . -The relative tissue displacements are mapped to the image ECR 2012 / C-1477

5. Virtual Touch Tissue Imaging (VTI) The degree of displacement is interpreted into degree of lightness and darkness in the regions of interest The more light color = the more compliant tissue = benign lesion. The darker color = the more hard tissue = malignant lesion.

6. The left image shows thyroid nodule by B mode. The right one :- VTI shows that the nodule appear dark in color = hard in consistency= malignancy .

7. Virtual Touch Tissue Quantification(VTQ) Push pulse (orange) generates shear waves (blue) ( mechanical waves propagates transversely in tissues) through a region of interest . Detection pulses (green) track the degree of displacement vs. time . The speed of the wave is computed . The speed of shear wave propagation is related to tissue stiffness. ECR 2012 / C-1477

8. Clinical applications--- characterize tissue stiffness Liver:-   Can estimate liver stiffness diagnosing cirrhosis. A safe and non-invasive alternative to liver biopsy. Differentiate   benign  from  malignant liver masses , Breast : Diagnosis of breast masses .   Prostate:- Help targeting prostate biopsy. Providing image guidance during focal therapy procedures. M onitor disease progression and response to treatment noninvasively . Thyroid --- Differentiation of thyroid nodules.

9. 1- Liver:- - 2D conventional US (a) and virtual touch tissue imaging (VTI, b). Tumor mass is markedly darker (stiffer) than adjacent hepatic parenchyma on VTI.

10. VTQ for liver fibrosis - Mean normal values range is about 0.8-1.22 m/s - Values predicting different stages of liver fibrosis were: F1 - 1.24 m/s F2 – 1.48 m/s F3 – 1.61 m/s F4 – 1.75 m/s 

11. 2- Breast:- - The left image shows breast mass in B mode. - The right one :- VTI shows that the mass appear dark in color = hard in consistency = malignant . Invasive ductal carcinoma Duke university

12. - The left image shows breast mass in B mode. - The right one :- VTI shows that the mass appear light in color = soft in consistency= benign . Fibroadenoma Duke university

13. 3- Prostate  ARFI imaging can clearly portray zonal anatomy and some cancerous lesions in the prostate. ARFI shows that the lesion is stiffer than the back ground material. ARFI and B-mode image volumes of  the prostate Duke university

14. 4-Thyroid 2D conventional US (a) and virtual touch tissue imaging (VTI, b) showing a dark color nodule (stiff nodule) P apillary thyroid carcinoma.

15. VTQ in thyroid lesions The median velocity in benign thyroid lesions are 2.06 m/sec and 3.0 m/sec in malignant lesions.

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17. 5- Kidney The mean shear wave velocity (SWVs) in normal adult kidneys were 2.24-2.37 m/sec. SWVs of 1.75 m/sec in children normal kidneys. SWVs increased in high-grade hydronephrotic kidneys (image B).

18. MINI QUIZ Right lobe thyroid nodule by B mode and ARFI------Benign or malignant ?

19. Mean shear wave velocity values HCC -----------------------------2.17 ml/s Hemangioma ------------------2.30 ml/s Adenoma ----------------------1.25 ml/s Metastasis ---------------------2.87 ml/s FNH ----------------------------=2.75   ml/s

20. A Qualitative implementation called virtual touch tissue quantification gives an objective numerical evaluation of the tissue stiffness . The calculation of the shear wave velocity mainly reflects the elasticity and viscosity of the target tissue. The harder the tissue the faster the velocity. Virtual touch tissue quantification

21. Elastography in predicting Lymph Node Malignancy The Elastographic pattern will findings will be classified into the following 4 patterns: Pattern 1: >80% of the color is red-green. pattern 2 50-80% of the color is red-green Pattern 3 (50-80% of the color is blue) Pattern 4 (>80% of the color is blue)

22. Thyroid nodules Four different patterns have been described including :- " patterns 3 and 4" that suggest malignancy While "patterns 1 and 2" indicate thyroid nodule benignity. 

23. Pancreas

24. Breast

25. Shear waves