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Thứ Hai, 23 tháng 5, 2016

MEDIC THAM DỰ 12th AFSUMB 2016, KYOTO JAPAN


Gồm 2 posters, download theo link=

arfi-on-adult-hydronephrosis

arfi-on-testes-medic-center





và  6 posters khác,
cùng 2 oral presentations về CAD và ARFI khối u vú do Dr Phan Thanh Hải Phượng báo cáo tại hội nghị lần thứ 12 của Asian Federation of Society for Ultrasound in Medicine and Biology [AFSUMB]  (27-29/5/2016) tại Kyoto



Sáng 29/5  Dr Phan Thanh Hải Phượng trình bày thành công 2 báo cáo miệng.




Thứ Hai, 28 tháng 3, 2016

WHAT MEANS POINT-SHEAR WAVE ELASTOGRAPHY [p-SWE]?


Ultrasound based-elastographic techniques are classified in: strain techniques and shear
wave elastography  techniques. Three  types of elastographic  techniques are  included
in  the  last category: Transient Elastography, point Shear Wave Elastography  (pSWE)
and shear wave elastography (SWE) imaging (including 2D-SWE and 3D-SWE). 

In the pSWE category two techniques are included: Acoustic Radiation Force Impulse (ARFI) elastography and ElastPQ.



Elastographic Techniques Based on Shear Waves Generated by the Acoustic Beam

These techniques have the advantage of being integrated into ultrasound systems; thus, conventional sonography, which is advised every 6 to 12 months in patients with chronic liver disease, could also be performed. As of today, for the assessment of liver stiffness, these techniques are commercially available in high-end ultrasound systems made by Philips Healthcare (Bothell, WA; ElastPQ), Siemens Medical Solutions (Mountain View, CA; Virtual Touch Tissue Quantification [VTTQ]), and SuperSonic Imagine, SA (Aix-en-Provence, France; ShearWave Elastography [SWE]). These techniques generate shear waves inside the liver by using radiation force from a focused ultrasound beam. The shear waves are generated near the region of interest in the liver parenchyma and not on the surface of the body, as happens with external vibration devices. The ultrasound system monitors shear wave propagation using a Doppler-like ultrasound technique and measures its velocity. The shear wave velocity is displayed in meters per second or kilopascals through the Young modulus. Unlike transient elastography, the measurements are not limited by the presence of ascites because the ultrasound beam, which generates the shear waves, propagates through fluids. With the VTTQ and ElastPQ techniques, the readings of the shear wave speed are made by using a small sample box (usually 0.5 × 1 cm); thus, a quantitative estimate of liver stiffness at a single location is obtained (Figures 2 and 3). They have been categorized as point–shear wave elastography.The SWE technique is based on an ultrafast ultrasound imaging approach that allows detailed monitoring of the shear waves in a large area of liver parenchyma with real-time color-coded elasticity imaging inside a sample box, and the measurement is obtained by placing a region of interest inside the sample box (Figure 4). This technique is 2-dimensional elastography.27 In all of the studies that have assessed the accuracy of the different devices in staging liver fibrosis, right intercostal access has been used. The patient is examined in the dorsal decubitus position with the right arm elevated above the head for optimal intercostal access in a resting respiratory position. Measurements are performed at least 1.5 to 2.0 cm beneath the Glisson capsule to avoid reverberation artifacts. In case of physical conditions affecting the signal to-noise ratio, the Philips and Siemens devices do not give any measurement. With the SuperSonic Imagine device, a measurement fails when no/little signals are obtained in the sample box for all of the acquisitions.




Siemens Technique (VTTQ)
The first one available was the Siemens technique, which is commonly referred to as acoustic radiation force impulse in the literature, which is technically the same force that generates shear waves for all 3 available techniques. Moreover, the term acoustic radiation force impulse is rather generic and does not identify shear wave–based methods. In fact, acoustic radiation force impulse push pulses are also used in strain imaging of other organs, such as the breast and thyroid. In recent years, the diagnostic accuracy of the VTTQ technology for quantification of liver stiffness, mainly in patients with chronic hepatitis C, has been investigated in several studies and a meta-analysis. The technology has shown high interobserver agreement, with an intraclass correlation coefficient of 0.86. Operator training does not seem to be required.The cutoff values obtained in a large meta-analysis were 1.34, 1.55, and 1.80 m/s for significant fibrosis (METAVIR fibrosis score of F2 or greater), severe fibrosis (METAVIR fibrosis score of F3 or greater), and cirrhosis (METAVIR fibrosis score of F4), respectively. In this meta-analysis, which included patients with several etiologies of chronic liver disease, the diagnostic accuracy was comparable with that of transient elastography for the assessment of severe fibrosis, whereas higher performance of transient elastography was seen for significant fibrosis and liver cirrhosis. In a study by Rizzo et al, the technique was significantly more accurate than transient elastography for diagnosing significant and severe fibrosis, whereas this difference was only marginal for cirrhosis.


SuperSonic Imagine Technique (SWE)
The reproducibility of the SWE method is very high, with intraobserver intraclass correlation coefficients of 0.95 and 0.93 for an expert and a novice operator, respectively, and interobserver agreement of 0.88. As for conventional sonography, it is user dependent; thus, it is recommended that at least 50 supervised scans and measurements should be performed by a novice operator to obtain consistent measurements. Values obtained in a small series of healthy participants ranged from 4.92 kPa (1.28 m/s) to 5.39 kPa (1.34 m/s). In a pilot study conducted on 121 patients with chronic hepatitis C undergoing liver biopsy, the optimal cutoff values were 7.1 kPa (1.54 m/s) for significant fibrosis (METAVIR fibrosis score of F2 or greater), 8.7 kPa (1.70 m/s) for advanced fibrosis (METAVIR fibrosis score of F3 or greater), and 10.4 kPa (1.86 m/s) for cirrhosis (METAVIR fibrosis score of F4), and the technique was more accurate than transient elastography in assessing significant fibrosis. In another study, with respect to transient elastography, the technique showed higher accuracy in assessing mild and intermediate stages of fibrosis.

Philips Technique (ElastPQ)
The ElastPQ technique was the most recent to enter the market; thus, only a few studies have been published so far. With this technique, liver stiffness values in healthy volunteers have been reported to be less than 4.0 kPa (1.15 m/s). Ling et al found that men had higher values than women (3.8 ± 0.7 versus 3.5 ± 0.4 kPa, or 1.13 ± 0.48 versus 1.08 ± 0.37 m/s) and liver stiffness was comparable with different probe positions, examiners, and age groups. In a series that comprised 88 patients with chronic viral hepatitis and 33 healthy volunteers, the technique compared favorably with transient elastography in staging liver fibrosis, and healthy volunteers showed significantly lower values than patients with nonsignificant fibrosis.
 REFERENCES:


Bamber J, Cosgrove D, Dietrich CF, et al. : EFSUMB guidelines and recommendations on the clinical use of ultrasound elastography, part 1: basic principles and technology. Ultraschall Med 2013; 34:169–184.

Ferraioli et al: Shear Wave Elastography for Evaluation of Liver FibrosisJ Ultrasound Med 2014; 33:197–203 199

Thứ Bảy, 5 tháng 3, 2016

S W ELASTO into PLAQUE IMAGING from E C R 2016

ELASTOGRAPHY OFFERS NEW INSIGHTS INTO PLAQUE IMAGING




ELASTOGRAPHY OFFERS NEW INSIGHTS INTO PLAQUE IMAGING

Elastography has been used for many years to differentiate malignant from benign lesions, especially in the breast or liver. Experience in carotid artery disease is limited, but recent studies have shown that elastography may help to stratify plaque and reduce the risk of unnecessary surgery, as a Greek expert will show during a New Horizons session today at the ECR.
Stroke is one of the leading causes of death in developed countries; one third of cases are fatal and survival can come with considerable disabilities. In Europe alone, experts estimate that there are one million new ischaemic strokes per year and they expect this number to rise by 12% by 2020, as the population ages1. A wide spectrum of carotid artery diseases can lead to stroke, but atherosclerosis accounts for a significant percentage – about 20 to 30% of cases. Stenosis is typically a cause for atherosclerosis and is now being measured using ultrasound in symptomatic patients, who are usually treated with atherectomy. But it is not so clear how asymptomatic patients should be managed, according to Dr. Nikos Liasis, medical director of Affidea Greece, a pan-European medical service provider specialising in diagnostics investigations, clinical laboratories and cancer treatment services. “Despite many randomised clinical trials, there is a surprising lack of consensus regarding the treatment of asymptomatic patients,” he said ahead of his presentation during the session today. There is widespread agreement among physicians that many procedures are probably being performed with risks that are higher than the risk of the actual indications. “Ninety-two per cent of all atherectomies in the U.S. are undertaken in asymptomatic patients. On average, we operate on 16 patients to prevent one stroke in just five years, so we perform surgery on 15 people who may not need it, which is quite a high risk,” he said. The degree of stenosis is not the only predictive parameter for myocardial infarction or stroke. Therefore it has become crucial to be able to understand and stratify plaque morphology. The majority of myocardial infarctions and strokes are actually caused by plaque rupture. Thanks to histological findings, physicians know that unstable, vulnerable plaques, which are prone to rupture and distal embolisation, are those with a large lipid core and intraplaque haemorrhage. Inflammation is also a high risk factor for plaque rupture. Researchers have tried to establish whether it would be suitable to use ultrasound in everyday clinical practice to stratify plaque morphology, but the results combined with histopathological findings were poor. Liasis and his team at Affidea Greece, together with the University of Athens Medical School and the National Technical University of Athens, decided to conduct a prospective study in order to determine the contribution of ultrasound elastography to the description of plaque morphology. “Ultrasound elastography is based on the principle that so tissue deforms more than hard tissue. So plaques that are hard and stable deform less than so, vulnerable plaques,” he said. So far the few available papers on the topic focused on either shear wave or strain elastography. In his study, Liasis has compared both techniques against histopathological findings and he will present his results today. He estimates that the potential of both techniques for stratifying plaque is significant, and that they may be complementary in many ways as they offer information that is not accessible through B mode or Doppler flow and other US techniques. “Elastography enables the detection of the fibrous cap, the thickness or thinness of which is an indication of plaque instability, but it remains challenging to spot with traditional ultrasound. It also provides information about plaque smoothness and more accurate information on what is outside of the plaque. We have all the features that are characteristics of plaque morphology and which make plaque unstable,” he said. Elastography offers other benefits to consider for daily practice; it is radiation free, accessible and widely available. Furthermore, it does not require any patient preparation and the costs are low. Examination times are short compared with MRI and, unlike CT, there are no allergy risks linked to contrast agents use. However a number of technical limitations remain to be overcome and reproducibility is still challenging. “When plaque is calcified, we are not able to describe it because of the acoustic shadow. Our biggest disadvantage is subjectivity. Reproducibility is still an issue, but using appropriate examination protocols may help,” Liasis said. It will also be necessary to adapt the technique, which has been developed for lesions in superficial organs, to small pulsating vessels. “We need more prospective studies to evaluate its potential. US elastography in carotid plaque imaging is only a few years old. But our research is very promising to describe plaque,” he concluded.


1 Data gathered by Brainomix, Oxford University h‑ps://ec.europa.eu/easme/en/ sme/4065/brainomix-limited BY MÉLISANDE ROUGER 

Thứ Năm, 3 tháng 3, 2016

ARFI CÁC TUYẾN BỌT VÀ TUYẾN GIÁP ở MEDIC CENTER

ARFI CÁC TUYẾN BỌT và TUYẾN GIÁP ở MEDIC CENTER
  

Gần đây siêu âm đàn hồi bắt đầu được áp dụng vào lâm sàng để khảo sát u, bệnh tự miễn và bệnh nhiễm trùng của tuyến giáp và các tuyến bọt.


Những khảo sát riêng lẽ về siêu âm đàn hồi của  tuyến giáp và các tuyến bọt ghi nhận không có khác biệt theo tuổi và phái tính ở người trưởng thành. Tuy nhiên khảo sát siêu âm đàn hồi tuyến giáp và các tuyến bọt trong điều kiện bình thường và khảo sát  cùng lúc và trên cùng người được khám thì chưa có thông tin.

 Chúng tôi có ý định:


1/ tìm tương quan độ sinh echo của tuyến giáp và các tuyến bọt.
2/ tìm khác biệt giữa sinh echo tuyến giáp và tuyến mang tai trên cùng cá thể.

3/ định lượng độ đàn hồi tuyến giáp và các tuyến bọt .

Qua khảo sát 68 [34 nam, 34 nữ] cá nhân cùng lúc tuyến giáp và các tuyến bọt trong tình trạng khỏe mạnh, chúng tôi có kết quả như sau :


Giá trị trung bình vận tốc của sóng biến dạng ở mô tuyến giáp là = 1,58 ± 0,17m/s [ở nghiên cứu của NPB Quân và cs là:1,47 ± 0,41 m/s. Không có sự khác biệt vận tốc này với nhóm tuổi, nhưng có khác biệt với giới (p nhỏ hơn 0,05)].

Giá trị trung bình vận tốc của sóng biến dạng ở mô tuyến dưới hàm bình thường là 1,47± 0,015m/s [ ở nghiên cứu của AF Badea là =1,82 ± 0,41m/s cho cả 2 tuyến P và T].

Giá trị trung bình vận tốc của sóng biến dạng ở mô tuyến mang tai bình thường là 1,42 ± 0,015m/s  so với 1,54 ± 0,6 m/s ở nghiên cứu của I.Badea].

Khác biệt về độ đàn hồi tuyến giáp bình thường và các tuyến mang tai và dưới hàm không có ý nghĩa thống kê ( p nhỏ hơn 0,0001).




Tài liệu tham khảo chính:

Nguyễn Phước Bảo Quân, Nguyễn Hữu Thịnh: Bước đầu nghiên cứu siêu âm đàn hồi mô tuyến giáp ở người bình thường bằng phương pháp tạo hình và đo vận tốc sóng biến dạng qua kỹ thuật ARFI

Alexandru Florin Badea, Attila Tamas Szora, Elisabeta Ciuleanu, Ioana Chioreanu, Grigore Băciuţ, Monica Lupşor Platon, Radu Badea: ARFI quantitative elastography of the submandibular glands. Normal
measurements and the diagnosis value of the method in radiation submaxillitis.


Iulia Badea, Attila Tamas-Szora, Ioana Chiorean, Maria Crisan, Elisabeta Ciuleanu, Grigore Baciut, Mindra Badea: Acoustic Radiation Force Impulse quantitative elastography: a new  noninvasive technique for the evaluation of parotid glands.  A preliminary study in controls and in patients with irradiated nasopharyngeal carcinoma.

Thứ Hai, 22 tháng 2, 2016

SHEAR WAVE ELASTOGRAPHY from APLIO 500 TOSHIBA on LIVER FIBROSIS

DOWNLOAD FULLTEXT
http://www.toshiba-medical.eu/eu/wp-content/uploads/sites/2/2014/09/WP_MOIUS0074EA_Iijima_2014-09.pdf







Thứ Sáu, 12 tháng 2, 2016

Patient's Platelet Count can Increase the Risk for Hematoma in Liver Biopsy

Image-guided liver biopsy is safe, but not risk-free
By Erik L. Ridley, AuntMinnie staff writer
February 11, 2016 -- While major adverse events from liver biopsy guided by ultrasound or CT are extremely rare, variables such as the patient's platelet count can increase the risk for hematoma from the procedure by as much as fourfold, according to a large retrospective analysis performed at the Mayo Clinic in Rochester, MN.


Thứ Ba, 9 tháng 2, 2016

Thứ Sáu, 5 tháng 2, 2016

CHÚC TẾT 2016





CHÚC MỪNG NĂM MỚI BÍNH THÂN 2016 AN KHANG THỊNH VƯỢNG.

MEDIC ARFI in BREAST TUMORS

CLINICAL FINDINGS of ARFI in BREAST TUMORS

VO NGUYEN THUC QUYEN, PHAN THANH HAI, MEDIC MEDICAL CENTER,
HCMC, VIETNAM
INTRODUCTION:
Breast Cancer is currently the top cancer among women worldwide including Viet nam. Therefore, early detection plays a critical role in clinical decision of management.
Besides Mammography and MRI, ultrasound has been a useful modality in detecting breast tumors. Moreover, the combination with Color Doppler significantly reinforces the B-mode diagnosis. Lately, new ultrasound technique, elastography is providing more information to increase accuracy. However, each one uses different method including compressed and non-compressed technologies. Developing by Siemen, ARFI is a non-compressed elastography, evaluates tissue stiffness base on replacement caused by acoustic radiation force impulse (ARFI). In other words, tissue deformed and reformed  under a force. The stifferness replaces less compared with surrounding tissue in same depth. In clinical application, tumors usually harder than healthy tissue.
AIMS:
To evaluate ARFI qualitative and quantitative assessment to differentiate benign and malignant breast tumors.
METHODS and MATERIALS
Patient and Pathologic diagnosis:
From April to November 2015, we selected 85 breast lesions classified as category 3-5 according to ACR Breast Imaging Recording and Data System (BI-RADS). Two radiologists analyzed them in the following steps before performed biopsy with final diagnosis (FNAC, Core Biopsy, Excisional Biopsy). All images and biopsy procedures were performed at Medic Medical Center Ho Chi Minh city. Exclusion criteria include:
·         Non histopathology confirmation
·         Male breast lesions
Imaging methods:
Using linear probe 9L4 (9MHz) in Siemens Acuson S2000, we applied respectively 2 modes:
·         VTI (Virtual Touch Quantification): an gray-scale elasticity map within region of interest (ROI)
·         VTQ: (Virtual Touch Quantification): quantitatively measure shear-wave speed (m/s) within non-resizable ROI. The ROI was set in multiple point of the lesion to get the mean measurement.
Step 1: scan B-mode and Color Doppler images, classified lesion using BI-RADS lexicon (shape, orientation, border, echotexture, posterior feature)
 Step 2: Acquired Elasticity Score (E.S) in VTI mode then measure Area Ratio (proportion between VTI lesion area and B-mode area). Base on VTI map, we classified lesions with 5 elasticity score: Figure
            Score 1: totally white
            Score 2: mosaic (mix multi-shade of grey and white)
            Score 3: black core with white or grey or mix
            Score 4: totally or near to complete black
            Score 5: totally black with black component out of lesion
Score1-3: low suspect of malignancy
Score 4-5: high suspect of malignancy

Step 3: Set ROI in 5 different points of the lesion then measured Shear-wave Velocity (SWV) in VTQ mode. We calculated mean velocity for each lesion. The ROI in VTQ mode are fixed with 5 x 5 mm in size. When acquired velocity reach over 9.10m/s or computer is unable to get the signal, we have X.XX m/s as value. [1] Figure 2.







Figure 2: Shearwave travels through hard tissue very fast with > 9.10m/s (X.XX m/s value)
Statistic analysis:
We use SPSS version 16.0 to identified cut-off value and obtain ROC for best value of sensitivity and specificity. Once we get cut-off value, we use t-student analysis to see whether benign and malignant populations were statistically different.
           
RESULT
This study was approved by the institutional review board and informed consent was obtained from all participants. From April to November 2015, we selected 85 breast lesions including 59 benign (69.4%) and 26 (30.6%) malignant. Lesions appear to dominantly locate in right breast 52/85 (61.2%), left 33/85 (38.8%). The mean size 16.26 ±6.56 width and  9.64 ±5.01 mm depth
Histopathologic diagnosis
n (%)
Malignant:  Invasive ductal carcinoma
26 (29.4)




Benign
59 (70.6)
Fibroadenoma
5 (5.9)
Mastitis
3 (3.5)
Intraductal papilloma
2 (2.4)
Fibrocystic change
46 (55.3)
Others
3 (3.5)
Total
85 (100)
Table 1: histopathlogic diagnosis of malignant and benign breast lesions
ARFI analysis
-VTI:
a/ Elasticity Score (E.S)

Malignant (%)
Benign (%)
ES 1
0
0
ES 2
0
52.5
ES 3
0
47.5
ES 4
23.1
0
ES 5
76.9
0
Total
100
100
Table 2.1: ES Score frequency of malignant and benign lesion
As the table 2.1, 26/26 cancer cases has ES 4-5 within suspicious range.
b/ Area ratio (A.R)
Area Ratio
Sensitivity (%)
Specificity (%)
1.06
100
27.2
1.13
96.2
52.5
1.20
88.5
64.4
1.34
88.5
94.9
1.40
84.6
96.6
1.44
84.6
98.3
Table 2.2:

As the table 2.2, the AR cut-off point would best at 1.34 with sensitivity 88.5% and specificity 94.9%. Area under ROC curve for malignancy is 0.933.
-VTQ:
We excluded 8 malignant cases has SWV as X.XX m/s
SWV
Sensitivity (%)
Specificity (%)
2.20
100
69.5
2.24
94.4
72.9
2.32
88.9
79.7
2.41
83.3
83.1
2.49
77.8
88.1
Table 2.3:
As the table 2.3, the SWV cut-off point would best at 2.24 with sensitivity 94.4% and specificity 72.9%. Area under ROC curve for malignancy is 0.911.
DISCUSSION
The ability of early detection
ARFI helps in differentiate malignant and benign lesion. E.S score in VTI mode suggest suspicion are quite accurate in this study (26/26). The gray-scale map not only distinguish big tumors but also in small tumors as case demonstrated (Figure 3). It could greatly aid in early detection.
Figure 3: A DCIS 6 x 5 mm mass with BI-RADS 5 in B-mode and ES 5, infiltration is clearly demonstrated which is not visible on conventional B-mode.
In term of quantitative evaluation, Area Ratio reinforced E.S. It also shows a better the cancerous infiltration in surrounding tissue than conventional method. In conventional ultrasound, only when halo rings, architecture distortion, skin changes suggest infiltration. However, those present in late stage while we are aiming for early detection. (Figure 4)
Firgure 4: non-halo tumors with AR=1.81 is better demonstrated the surrounding invasion
Our cut-off value
Our SWV cut-off point at 2.24 m/are suitable for clinical practice. Other reference studies were significantly higher (Yoon Seok Kim et al: 4.23±1.09 m/sec [2]) as they considered all X.XX value as 9.10m/s. We excluded all X.XX value since it not actually equals 9.10m/s.
Role in clinical diagnosis
In clinical application, ARFI increases the accuracy of B-mode and Color Doppler. It most value in BI-RADS 3-4a lesion which are the borderline between benignity and malignancy. We recommended grade up from BI-RADS 3 to 4A if all ARFI features are suspicious. However, here are some exceptions. Acknowledged that some cancer such as Inflammatory Breast Cancer (IBC) tends to be softer than normal tissue, reversely, some benign condition like Mastitis can mask malignancy (figure 5). Our study limited in 85 case and not included any IBC however caution should be made if specially AR> 1.34. An interesting study was held by M.Teke et al. which used ARFI to compare Idiopathic Granulomatous Mastitis with Breast Cancer . Study shown significantly different between their SWV (cut-off value 4.08m/s with 80.6% sensitivity, 86.4% specificity). It is important not to miss cancer but still minimalize invasive option. EFSUMB also recommend this concept but less certain in down grade. In some situation, we can down grade 4A lesion if the technique done right, such as circumscribed lesion with suspicious Doppler pattern or posterior feature. ARFI also helps guiding FNA procedure as we puncture the hardest points in the lesion on VTI map.  

Figure 5: Mastitis lesion in 60 years old patient, BI-RADS 4C E.S 2, AR=1.1 and VTQ=1.58m/s


Technical recommendation


CONCLUSION
Overall, ARFI is a useful tools for diagnosis and biopsy guidance breast tumors. The technique is simple since it is non-compressed and repeatable. It cannot replaced biopsy but reinforced conventional ultrasound. This is a promising technique helps avoiding invasive diagnosis if we use it right and well-combined with other features.

REFERENCES:
1/ Wojcinski S, Brandhorst K, Sadigh G, Hillemanns P, Degenhardt F. Acoustic radiation force impulse imaging with Virtual TouchTM tissue quantification: mean shear wave velocity of malignant and benign breast masses. International Journal of Women’s Health. 2013;5:619-627. doi:10.2147/IJWH.S50953.
2/ Kim YS, Park JG, Kim BS, Lee CH, Ryu DW. Diagnostic Value of Elastography Using Acoustic Radiation Force Impulse Imaging and Strain Ratio for Breast Tumors. Journal of Breast Cancer. 2014;17(1):76-82. doi:10.4048/jbc.2014.17.1.76.
3/ M. Teke, M. Gümüş, F. Teke. Combination of elastography and tissue quantification using the acoustic radiation force impulse technology for differential diagnosis of Idiopathic Granulomatous Mastitis with Breast Cancer. ECR 2015 http://dx.doi.org/10.1594/ecr2015/C-1835

4/D. Cosgrove1, F. Piscaglia2, J. Bamber3. EFSUMB Guidelines and Recommendations on the Clinical Use of Ultrasound Elastography.Part 2: Clinical Applications. Ultraschall in Med 2013 DOI: 10.1055/s-0033-1335375