posters and oral presentations on s w e rsna 2011

POSTERS AND ORAL PRESENTATIONS

ON SHEARWAVE™ ELASTOGRAPHY

AT RSNA 2011

Last update: 11/17/2011 RSNA 2011 Communications

RSNA 2011

Shear Wave Elastography Findings in Breast, Thyroid, Liver, and Prostate Diseases SY Kim MD, WK Jeong MD, YS Kim MD, PhD, MY Kim MD, JS Park MD

Purpose / Aim 1. To explain basic physics and scanning techniques in shear waves elastography. 2. To

present imaging findings of shear waves elastography in breast, thyroid, liver and

prostate diseases. 4. To understand that shear waves elastography provides quantitative

informations. 4. To discuss possible shortcomings of shear waves elastography.

Content Organization 1. Basic physics and scanning technique of shear waves elastography.

2. Review of imaging findings of benign and malignant cases

- Correlation with B-mode images

- Pattern of color coded images and quantitative values of elasticity

3. False negative and false positive cases

4. Summary

Summary 1. Shear waves elastography use the mechanical wave induced by acoustic radiation

force of ulrasound to perturb underlying tissues.

2. Shear waves elastography represents different elastic values and color image patterns

of pathologies.

3. Knowledge of potential shortcomings of shear waves elastography may help to

discrimnate benign to malignant diseases.


Publications on Aixplorer® ShearWave™ Elastography

BREAST


RSNA 2011

Specificity Is Improved When ShearWave Elastography (SWE) Is Added to BI-RADS

® for Breast Ultrasound:

Prospective Multicenter International Validation in the BE1 Study WA Berg1 MD, PhD, DO Cosgrove2 MBBCh, FRCR, C Dore3, FKW Schaefer4 MD, W Svensson5 MD, J Gay6, JP Henry6, C Cohen Bacrie MD, PhD6 1 Magee-Womens Hospital of UPMC, Pittsburgh, PA, USA; 2Hammersmith Hospital, London, UK ; 3London, UK; 4 Universitätsklinikum Schleswig-Holstein, Campus Kiel, Germany; 5 Charing Cross Hospital, London, UK; 6SuperSonic Imagine, Aix-en-Provence, France

Purpose To validate performance prospectively when ShearWave™ elastographic (SWE™) features

are added to BI-RADS® assessments of breast masses.

Method and Materials From 9/2008 to 9/2010, 701 women consented to repeat breast ultrasound plus

quantitative SWE examination in this IRB-approved, HIPAA-compliant protocol conducted

at 16 centers in Europe and the United States. BI-RADS (BR) features and assessments

were recorded. Mean, maximum (Emax), and minimum elasticity of the stiffest portion of

the mass and surrounding tissue, lesion-to-fat elasticity ratio, ratio of SWE-to-B-mode

lesion diameter, SWE lesion shape, and homogeneity were evaluated. 623 masses were

analyzable: 42 BR 2 masses were assumed benign, and reference standard was available

for 581 BR 3 or greater masses. We used reclassification thresholds developed on an

earlier series of 939 masses to selectively upgrade BR 3 masses to biopsy and

downgrade 4a masses to follow-up, and impact of SWE after BR on sensitivity, specificity,

and AUC was determined.

Results Median participant age was 50.4 years (mean 51.7, range 21.1 to 89.6) with median

mass size 12 mm (mean 14.3, range 2 to 50); 213/623 (34.2%) masses were malignant.

3/137 (2.2%) BR 3 masses were malignant as were 22/208 (10.6%) 4a, 17/48 (35.4%)

4b, 22/35 (62.8%) 4c, and 149/153 (97.4%) of BR 5 lesions. Calibration of original

model in the validation sample showed no evidence of significant lack of fit (p=0.51). All

SWE features except diameter ratio significantly improved specificity (p≤0.001). Using

SWE homogeneity or Emax ≤80 kPa to downgrade BR4a and inhomogeneity or Emax

≥160 to upgrade BR3 improved specificity from 176/410 (42.9%) for BI-RADS alone to

315/410 (76.8%, p<.0001) and 298/410 (72.7%, p<.0001) respectively, without

significant change in sensitivity; AUC increased from 0.942 with BI-RADS alone to 0.952

(p=.04), and 0.954 (p=.01) respectively. The 0.954 AUC for the validation sample was

similar to our original model (0.962).

Conclusions In a prospective, multicenter validation set of 623 masses, we confirm that addition of

SWE maximum elasticity ≥160 kPa to upgrade BI-RADS 3 masses and ≤80 kPa to

downgrade BI-RADS 4a masses yields a 30% absolute improvement in specificity of

breast ultrasound mass assessment without loss of sensitivity.

Clinical Relevance Addition of SWE to standard breast ultrasound can significantly reduce unnecessary

biopsies among low suspicion breast masses.


RSNA 2011

Increasing Quantitative Maximum Stiffness by Shearwave Elastography (SWE) Predicts Increasingly Severe Histopathology of Breast Masses W Berg1 MD, PhD, E Mendelson2 MD, D Cosgrove3 MBBCh, FRCR, C Doré4 BSC, J Gay5, JP Henry5, C Cohen Bacrie5 MD, PhD 1 Magee-Womens Hospital of UPMC, Pittsburgh, PA, USA; 2 NorthWestern Memorial Hospital, Chicago, IL, USA; 3 Hammersmith Hospital, London, UK, 4 London, UK; 5 SuperSonic Imagine, Aix-en-Provence, France

Purpose To compare quantitative maximum breast mass stiffness on SWE with histopathologic

outcome.

Method and Materials From 9/2008 to 9/2010, across 16 centers in Europe and USA, 1647 women with breast

masses consented to repeat ultrasound and quantitative SWE imaging (SuperSonic

Imagine, Aix, France). 1562 women/masses had acceptable reference standard.

Quantitative maximum elasticity (Emax) across three acquisitions was recorded, with

range set 0 (very soft) to 180 kPa (very stiff). Median Emax, and interquartile ranges

were determined as a function of histopathology, and compared using Mann-Whitney

tests.

Results Median patient age: 50 yrs (mean 51.8; SD 14.5; range 21 to 94); lesion diameter, 12

mm (mean 14; SD 7.9; range 1 to 53). Median Emax across 1562 masses (32.1%

malignant) was 71 (mean 90; SD 65; IQR 31 to 170). Of 501 malignancies, 23 (4.6%)

were DCIS with Emax 126 (IQR 71 to 180), less stiff than 467 invasive carcinomas

[Emax 180 (IQR 138 to 180; p=.0017)]; 12 other malignancies had Emax 170 (IQR 54

to 180). Overall, benign lesions were much softer than malignancies (Emax 43, IQR 24 to

83; vs. 180, IQR 129 to 180; p<.0001). Eight lipomas (Emax 14, IQR 8 to 15), 154 cysts

(Emax 29, IQR 9 to 58) and 7 IMLN (Emax 17, IQR 9 to 40) were softer than other

benign lesions (p<.0001 for lipomas and cysts; p=.007 for IMLN). Aspirated cysts were

stiffer than simple cysts: Emax 35 vs. 23 (p=.012). Common benign lesions were soft:

62 FCC (Emax 32, IQR 24 to 94); 51 stromal fibrosis (Emax 36, IQR 22 to 102); 299

fibroadenomata (Emax 45, IQR 30 to 79); 420 nonspecific benign/BI-RADS 2 no biopsy

(Emax 45, IQR 25 to 85). High-risk lesions were slightly stiffer than common benign

lesions (p=.002) but tended to be softer than DCIS (p=.14): 13 fibroepithelial lesions

(Emax 68, IQR 29 to 170); 5 ADH/LCIS (Emax 82, IQR 42 to 132); 17 papillomata

(Emax 100, IQR 41 to 176); 2 radial scars (Emax 104, IQR 29 to 180). 20 Fat necrosis

(Emax 85; IQR 29 to 140) and 2 abscesses (Emax 133; IQR 87 to 180) were relatively

stiff.

Conclusion As groups, cysts, lipomas, and IMLN are softer than fibroadenomata, FCC, or fibrosis.

High-risk lesions and DCIS are intermediate in stiffness. Invasive carcinomas are stiffer

than any other class of breast masses.

Clinical Relevance/Application Despite some overlap, maximum stiffness by SWE is highly effective at predicting the

severity of histopathology of sonographically-depicted masses.


RSNA 2011

Diagnostic Performance of SHEARWAVE Elastography (SWE) Added to BI-RADS

®: US for Masses ≤10mm

DO Cosgrove 1 MBBCh, FRCR, WA Berg2 MD, PhD, C Dore3, J Gay4, AT Stavros5 MD, EB Mendelson6 MD, FKW Schaefer7 MD, W Svensson8 MD 1Hammersmith Hospital, London, UK ; 2 Magee-Womens Hospital of UPMC, Pittsburgh, PA, USA; 3London, UK; 4SuperSonic Imagine, Aix-en-Provence, France; 5 Sutter Pacific Women’s Health Care, Santa Rosa, CA, USA; 6NorthWestern Memorial Hospital, Chicago, IL, USA; 7 Universitätsklinikum Schleswig-Holstein, Campus Kiel, Germany; 8 Charing Cross Hospital, London, UK

Purpose To determine the diagnostic performance of SWE added to BI-RADS:US for

subcentimeter masses.

Method and Materials Of 1647 women recruited to the HIPAA compliant BE1 study across 16 centers in Europe

and the USA, 637 masses 10 mm and smaller were analyzable with reference standard of

biopsy, FNAB (BI-RADS 4a, 4b, 4c, or 5), or at least one year follow-up (BI-RADS 3); BI-

RADS 2 masses were presumed benign. After the routine scan, three SWE acquisitions

were obtained for each mass using a prototype of the Aixplorer system (SuperSonic

Imagine, Aix-en-Provence, France). A 2x2mm ROI was placed on the stiffest part of the

mass using the color scale as a guide. The scale was preset to a maximum value of

180kPa and maximum elasticity recorded across 3 acquisitions (Emax). Threshold values

were used to upgrade BI-RADS 3 masses to biopsy with Emax ≥160 and downgrade BI-

RADS 4a masses to follow-up with Emax <80.

Results 182 (28.6%) small masses were malignant. For 206 BI-RADS 3 masses (6, 3%

malignant), higher malignancy rates were seen with higher Emax: 1% (2/170) for Emax

<80, 7% (2/28) for Emax 80-<160 and 25% (2/8) for Emax ≥160 (p<.001). 26/187

(14%) BI-RADS 4a masses were malignant: 8/141 (6%) with Emax <80, 12/30 (40%)

with Emax 80-<160 and 6/16 (38%) with Emax ≥160 (p=.001). For small masses

specificity improved (p<0.001) from 247/455 (54.3%) for BI-RADS alone to 374/455

(82.2%) when SWE was considered, with slight loss of sensitivity (p=0.06) 176/182

(96.7%) vs 170/182 (93.4%). For large masses specificity improved (p<0.001) from

326/605 (53.9%) for BI-RADS alone to 427/605 (70.6%) with slight gain of sensitivity

(p=0.18) 315/320 (98.4%) vs 318/320 (99.4%). For all masses, stiffness increased by

1.1 kPa per mm increase in size (0.80-1.42, p<0.001). Malignant masses averaged 88

kPa stiffer (83-93, p<0.001) than benign.

Conclusions Small cancers ≤10 mm are significantly stiffer than small benign masses, but less stiff

than larger malignancies. A few malignancies will be misclassified as benign-appearing by

both BI-RADS and SWE, and this is more common with smaller masses than those

>10mm.

Clinical Relevance An absolute increase in specificity of nearly 28% can be achieved when Emax is

considered for BI-RADS 3 and 4a masses 10mm or smaller.


RSNA 2011

Soft Breast Cancers: Patterns and Pitfalls in ShearWave™ Elastography (SWE) in the BE1 International Multicenter Trial EB Mendelson1 MD, WA Berg2 MD, PhD, M Feldman1 MD, MBA, DO Cosgrove 3 MBBCh, FRCR, J Gay4, C Cohen Bacrie5 PhD 1NorthWestern Memorial Hospital, Chicago, IL, USA; 2 Magee-Womens Hospital of UPMC, Pittsburgh, PA, USA; 3Hammersmith Hospital, London, UK ; 4SuperSonic Imagine, Aix-en-Provence, France

Purpose SWE shows most cancers to be stiff. Our goal was to see if there are SWE predictive color

patterns in lesions grouped by Emax as very soft (<30kPa) or relatively soft (<80 kPa)

contributing to accuracy of BI-RADS assessments.

Method and Materials From 9/2008 to 9/2010 in 16 centers in the USA and Europe (BE1 Trial, SuperSonic

Imagine, Aix-en-Provence, FR)1562 breast masses were evaluated with B-mode

ultrasound (US) and SWE. Thresholds of <30 kPa for very soft cancers and <80 kPa for

relatively soft cancers were set based upon previously determined Emax thresholds for

downgrading BI-RADS 4a masses to follow-up rather than biopsy, increasing specificity

without net loss in sensitivity provided that very stiff BI-RADS 3 masses with kPa >160

were upgraded to biopsy. From the database, ultrasound (US) images and site-assigned

B-mode BI-RADS assessments of each of these pathology-proved soft cancers were

reviewed. The placement of ROI's in lesion and background tissue were checked for

technical accuracy, and we tallied SWE color overlay patterns including background tissue

color, lesion color, hetero- or homogeneity of the color overlay, and presence of a

perilesional rim.

Results 367/1562 (23.5%) masses were very soft, with 6 malignant. 470/1562 (30.1%) were

relatively soft. Of these, 45 (9.6%) were malignant. Of the 6 very soft cancers, 2 were

BI-RADS 4A, or 0.5% of the 367 very soft masses; the other 4 were assessed as BI-

RADS 4B-5. Of the 470 relatively soft masses, 45 (9.6%) were malignant, 2 (0.4%) BI-

RADS 3, 9 (1.9%) 4A, and 34 (76%) were 4B and higher. Only 5/501(1%) soft cancers

(3-4A) and 9/501 4B and higher (1.8%) had classic benign blue mass in homogeneously

blue background. All other soft cancers were marked by partial or complete turquoise

(lighter blue-green) rims (5 masses in BI-RADS 3-4A & 18 in 4B-5, 23/51 or 45.1% of

soft cancers) aound blue or blue-black masses, & most, even small masses <1 cm, had

suspicious B-mode features, or "blips," 3 mm focal areas of turquoise or (10 blips in BI-

RADS 3-4A and 21 in 4B-5, total 31/51 or 60.8%). Placement of ROI was inconsistent

prior to 3/2009, & Emax possibly underestimated.

Conclusions Most malignant masses are stiff by quantitative elastographic criteria as well as their

color depictions. Relatively few cancers are soft, such as some high grade invasive ductal

carcinomas, and SWE should not be used to downgrade masses suspicious on BI-RADS

feature analysis; turquoise rims and blips can suggest that a soft lesion (Emax < 80 kPa)

may require biopsy.

Clinical Relevance SWE should not be used to downgrade masses that are suspicious based on BI-RADS

feature analysis; color heterogeneity and rim patterns may be supportive of BI-RADS

assignments of 4B and higher.


RSNA 2011

Clinical Application of Shear Wave Elastography (SWE) in the Diagnosis of Benign and Malignant Breast Diseases JM Chang MD, WK Moon, N Cho MD, A Yi MD, HR Koo MD, SJ Kim.

Purpose To evaluate the diagnostic performance of shear wave elastography (SWE) for the

differentiation of breast masses compared with conventional ultrasound (US).

Materials and Methods Conventional US and SWE were performed by three experienced radiologists for 158

consecutive women who had been scheduled for US-guided core biopsy or surgical

excision in 182 breast masses (89 malignancies and 93 benign; mean size, 1.76 cm). For

each lesion, quantitative elasticity was measured in terms of the Young’s modulus (in

kilopascals, kPa) with SWE, and BI-RADS final categories were assessed with

conventional US. Sensitivity, specificity, and the area under the curve (Az) by receiver

operating characteristic (ROC) curve analysis were obtained for SWE and conventional US

to evaluate diagnostic performance.

Results

The mean elasticity values were significantly higher in malignant masses (153.3 kPa ±

58.1) than in benign masses (46.1 kPa ± 42.9), (P <0.0001). The average mean

elasticity values of invasive ductal (157.5 ± 57.07) or invasive lobular (169.5 ± 61.06)

carcinomas were higher than those of ductal carcinoma in situ (117.8 kPa ± 54.72). The

average mean value was 49.58 ± 43.51 for fibroadenoma, 35.3 ± 31.2 for fibrocystic

changes, 69.5 ± 63.2 for intraductal papilloma and 149.5 ± 132.4 for adenosis or

stromal fibrosis. The optimal cut-off value, yielding the maximal sum of sensitivity and

specificity, was 80.17 kPa, and the sensitivity and specificity of SWE were 88.8% (79 of

89) and 84.9% (79 of 93). The area under the ROC curve (Az value) was 0.898 for

conventional US and 0.932 for SWE (P = 0.250). When category 4 lesions with elasticity

values higher than 80.17kPa, and category 5 lesions regardless of elasticity findings

considered as test positive, the sensitivity and specificity were 95.5% (85 of 89) and

88.2% (82 of 93), showing higher value than those of individual conventional US and

SWE.

Conclusions There were significant differences in the elasticity values of benign and malignant masses

as well as invasive and intraductal cancers with SWE. Adding SWE data to conventional

US could increase diagnostic performance for the differentiation of variable breast

masses.

Clinical Relevance/Application Knowing quantitative values of various breast lesions in a larger population will

potentially increase our level of confidence regarding the final assessment of various

breast lesions.


RSNA 2011

Comparison of Commercially Available Shear Wave and Static US Elastography Systems for Differentiation of Benign and Malignant Breast Masses JM Chang MD, WK Moon, N Cho MD, SJ Kim

Purpose To prospectively compare the diagnostic performance of shear wave and static US

elastography systems for differentiation of benign and malignant breast masses.

Materials and Methods Between March 2010 and April 2010, 125 women (mean age 47 years, range 22 – 75

years) with 156 breast masses (mean size 19 mm, range 4-80 mm) (76 malignant, 80

benign) underwent US elastographic examinations with both systems (shear wave and

static US elastography) by one radiologist prior to biopsy. Probability of malignancy

based on conventional US findings was recorded prior to US elastography. With shear

wave system, quantitative elasticity values in kiloPascal units measured was recorded.

For static elastography, the elasticity score (1-5) based on the degree and distribution of

strain proposed by Itoh et al. (Radiology 2006; 239:341–350) was given. Diagnostic

performance of the two systems in distinguishing benign from malignant masses was

compared using receiver operating characteristic (ROC) curve analysis and McNemar’s

test using histological analysis as a reference standard.

Results The area under the ROC curve for the static elastography system (Az=0.948) was similar

to that of the shear wave elastography system (Az=0.917) (difference between areas

0.02, 95% CI - 0.01-0.07, P=0.172). The best cut-off values, yielding the maximal sum

of sensitivity and specificity, were between values in kiloPascal units of 57.7 and

elasticity scores of 3 and 4. The sensitivity of the shear wave elastography system was

higher than that of the static elastography system [98.7% (75 of 76) vs. 78.9% (60 of

76), P = 0.0001] and the specificity of the static elastography system was higher than

that of the shearwave elastography system [96.3% (77 of 80) vs. 71.2% (57 of 80), P =

0.001].

Conclusions Two systems showed similar overall diagnostic performance. However the shearwave

elastography system showed better sensitivity, and the static elastography system

showed better specificity with the certain fixed cutoff values in distinguishing benign from

malignant breast masses.

Clinical Relevance/Application Understanding the characteristics of both shear wave elastography and static

elastography systems can be helpful in optimizing the diagnostic criteria for each system.


RSNA 2011

Breast Elastography: Strain vs Shear Wave Competitors or Allies RG Barr MD, PhD

Purpose / Aim To review the advantages and limitations of strain and shear wave breast elastography.

Review techniques, artifacts and interpretation. To demonstrate how the techniques

compliment each other.

Content Organization A. Review of strain and shear wave elastography B. Advantages and limitations of both

techniques C. Review artifacts D. Clinical examples of each technique E. Clinical examples

demonstrating when both techniques are used additional diagnostic information is

obtained.

Summary The use of both strain and shear wave imaging improve breast lesion characterization.

The use of both techniques is superior to each alone. This exhibit reviews: a. Prinicpals of

strain and shear wave elastography b. Appropriate technique for each exam c. How to

imtrepret each exam d. Review of artifacts e. Demonstrate the advantage of using both

techniques.


RSNA 2011

Imaging Spectrums of the Breast Shear Wave Elastography: Image-Histology Correlation SH Choi, EJ Ha, HS Mun, SH Kook MD, Y Choi MD

Purpose / Aim The purpose of this exhibition is:

1. To review the patterns of the stiffness depiction by elastography

2. To illustrate the variable image patterns of shear wave elastography according to new

BI-RADS with image-histology correlation.

3. To increase diagnostic specificity in diagnosis of breast imaging

Content Organization –Introduction

–The 5 patterns of stiffness depiction with elasticity values

Fluid pattern

Predominantly soft

Moderate soft

Predominantly firm

Firm with stiffness extending into surrounding tissue

–Representative cases with histopathologic correlation

–Pitfalls and tips

–Summary

Summary The major teaching points of this exhibit are:

1. The shear wave elastography provides the elasticity value, so the operator can assume

the benignity or malignancy of the mass.

2. The maximum elasticity value of the majority of malignancy is higher than 90kPa.

3. The pattern of elastography and the elasticity value are helpful for diagnosis in breast

disease.


RSNA 2011

The Principles of Elastography and Application in the Analysis of Breast Lesions M Rolen MD, R Hooley MD, J Geisel MD, R Butler MD, L Philpotts MD, L Scoutt MD

Purpose / Aim The purpose of this exhibit is: 1. To review the basic principles of elastography. 2. To

explain the various imaging features of shear wave elastography and methods of

measuring tissue stiffness. 3. To become familiar with elastography features of benign

and malignant breast lesions.

Content Organization Content/Organization: 1. Principles of static and shear wave elastography 2. Review of

the literature 3. Imaging features of breast lesions using shear wave elastography: a.

quantitative elasticity b. size ratios relative to B-mode c. shape d. homogeneity e.

sensitivity and specificity 4. Sample cases of common benign and malignant breast

lesions using grey scale, power Doppler and elastography. 5. Potential artifacts 6. Future

directions and summary

Summary The major teaching points of this exhibit are: 1. Elastography can measure breast tissue

stiffness. 2. Elastography is a promising tool that may help differentiate a variety of

benign and malignant breast masses seen on sonography.



THYROID


RSNA 2011

Shear Wave Elastography in the Differential Diagnosis of Thyroid Nodules and the Role of Autoimmunity S Alessi MD, E Nalon MD, C Bortolotto MD, B Gregoli MD, F Magri MD, F Calliada MD, L Chiovato MD

Purpose The purpose of the study is to establish the capability of shear wave elastosonography

(SWE) to correctly define thyroid nodules elasticity within a gland affected by

autoimmune thyroid disease (ATD) and without autoimmune disease.

Method and Materials We enrolled two groups of patients: 33 with Hashimoto’s thyroiditis, autoimmune thyroid

disease (ATD) with one or more thyroid nodules (ATD group) and 42 with nodular or

multinodular goitre negative for thyroid autoimmunity (non-ATD group). Inclusion criteria

were cytology indicative of benign lesion and absence of thyroid nodule with a dominant

cystic component. Thyroid ultrasound (US) and SWE were performed using Aixplorer

real-time US device, (SuperSonic Imagine, Aix en Provence, France) with SL 15-4 linear

transducer (4-15 MHz). The examiners were blind of the patient’s clinical data. The

following parameters of the thyroid and nodules were described: nature; echogenicity;

size; homogeneity; microcalcifications; halo sign and colour-flow Doppler pattern. Then

the nodules were evaluated by SWE: tissue elasticity results in a color-coded image, blue

representing softer tissue and red stiffer tissue. Quantitative information of elasticity

index (EI) was expressed in kilo-Pascal.

Results The elasticity index of the extranodular tissue was higher in the ATD group than in non

ATD group (24±10.5SD vs 20.8±10.4) and the differences were statistically significant (p

value<0.05); the elasticity index of thyroid nodules was similar in the ATD and the non-

ATD groups without any statistically significant difference. The stiffness of each nodule

was higher than that of the embedding tissue in both the ATD and the non-ATD group

and the difference was statistically significant (p value<0.05). Our data confirm the SWE

ability to correctly define thyroid nodules elasticity even in ATD patients.

Conclusion SWE seems to represent an important tool in the evaluation of thyroid nodules. This new

real time US technique may be applied independently from the co-existence of an

underlying autoimmune process, both to single nodule and to multinodular goitre.

Clinical Relevance/Application Elastography is a possible solution to evaluate histologically undefined thyroid nodules.

We demonstrated that even in ATD patients SWE is reliable in identifying thyroid nodules

stiffness values.



LIVER


RSNA 2011

Accuracy of Real-time Shear-Wave Elastography in the Assessment of Liver Fibrosis G Ferraioli MD, C Tinelli MD, MSC, B Dal Bello MD, R Lissandrin MD, G Michelone MD, C Filice MD Matteo Hospital Foundation, University of Pavia, Italy

Purpose This single center study of diagnostic accuracy was conducted to assess the accuracy of

non-invasive measurements of liver stiffness with real-time shear wave elastography

(RTSWE) in patients with chronic hepatitis and to compare the results with those of

transient elastography (TE) by using liver biopsy (LB) as the reference standard.

Method and Materials Consecutive patients with chronic viral hepatitis scheduled for liver biopsy by the

referring physician were studied. On the same day RTSWE using the ultrasound

equipment Aixplorer (Supersonic, Aix-en-Provence, France) with a convex multifrequency

probe, TE using FibroScanTM (Echosens, Paris, France) and ultrasound-assisted LB were

consecutively performed. RTSWE and TE were carried out in the same intercostal space

employed for LB. Fibrosis was staged according to the METAVIR scoring system. Receiver

operating characteristic curve analyses were performed to calculate area under the curve

(AUROC) for F0-F1 versus F2-F4, F0-F2 versus F3-F4, and F0-F3 versus F4 for both

RTSWE and TE.

Results Sixty-six patients were studied. Liver stiffness values increased in parallel with the

degree of fibrosis both with TE and RTSWE. AUROC calculations showed values of 0.83

(95% CI, 0.72-0.91) for TE and 0.88 (95% CI, 0.77-0.94) for RTSWE (p=0.24); 0.96

(95% CI, 0.87-0.99) for TE and 0.99 (95% CI, 0.92-1.00) for RTSWE (p=0.29); 0.96

(95% CI, 0.88-0.99) and 0.97 (95% CI, 0.89-1.00) for RTSWE (p=0.80) when

comparing F0-F1 versus F2-F4; F0-F2 versus F3-F4; and F0-F3 versus F4 respectively.

Conclusion These preliminary results show that the diagnostic performance of RTSWE in the

diagnosis and staging of liver fibrosis compares favourably with that of TE, suggesting

that this tool may represent a reliable diagnostic surrogate of histopathology assessment

of fibrosis.

Clinical Relevance/Application RTSWE is a promising non-invasive procedure for detecting and staging liver fibrosis and

has the potential to replace liver biopsy in some cases.


RSNA 2011

Measurement of Liver Stiffness by Shear Wave Elastography (SWE): Setting Up the Normal Range JY Lee, WK Jeong MD, YS Kim MD, PhD, MY Kim MD, SY Kim MD, SY Song, BH Koh MD, OK Cho MD, PhD

Purpose To set up the normal range of liver stiffness (LS) measured by Supersonic shear wave

elastography (SWE) and the cutoff level differentiated from chronic liver diseases

Method and Materials Of 351 patients who underwent liver ultrasonography coupled with SWE, normal group

(n=122) was defined as the person without any clinical evidence of liver disease and

normal laboratory and ultrasonographic features. Body mass index of them did not

exceed 25. Comparative groups were non-cirrhotic chronic liver disease (NCCLD; n=58)

and liver cirrhosis groups (LC; n=30). Underlying diseases of these groups were HBV

hepatitis (n=38) and alcoholic liver disease (n=50). LC was discriminated from NCCLD by

compatible clinical information and CT and ultrasonographic features. To measure LS, we

repeatedly performed SWE 10 times per patient, and investigated SWE parameters such

as mean LS and standard deviation (SD) of LS which might reflect the heterogeneity of

liver fibrosis. Then, we calculated the mean values and 95% confidence intervals (CI) of

the parameters in the normal group, and verified the normality of distribution by

Kolmogorov-Smirnov test. Then, we compared LS among normal, NCCLD and LC and set

up the cutoff level of LS to distinguish normal from NCCLD using ROC curve analysis.

Results In the normal group, mean value of LS was 5.54 ± 1.44 kPa (95% CI, 5.28-5.80 kPa)

and mean SD was 1.52 ± 0.52 kPa (95% CI, 1.43-1.61 kPa). The distribution of LS and

SD were proved normal (p=.379 and .176, respectively). Mean LS were 8.62 ± 3.58 kPa

(95% CI, 7.67-9.56 kPa) in the NCCLD and 17.50 ± 7.70 kPa (95% CI, 14.63-20.38 kPa)

in the LC, which was significantly discriminated from normal value (p<.001). SD were

2.35 ± 1.49 kPa (95% CI, 1.96-2.74 kPa) in the NCCLD and 7.37 ± 7.06 kPa (95% CI,

4.74-10.01 kPa) in the LC, but there was only a significant difference between normal

group and the LC (p<.001). The cutoff value of LS to distinguish normal group from

NCCLD was 6.92 kPa with 91% of sensitivity and 65.5% of specificity.

Conclusion The normal range of LS in the normal group was 5.28 to 5.80 kPa. The LS considered as

a cutoff level differentiated from chronic liver diseases was 6.92 kPa.

Clinical Relevance/Application This study can propose the reference level of liver stiffness in the normal population

measured by using a novel technique, shear wave elastography.


RSNA 2011

Evaluation Focal Hepatic Lesions Elasticity Using 2D Shear-Wave Elastography C Boularan, A Guibal MD, M Bruce PhD, T Lefort, G Renosi, T Walter, J Dumortier, F Pilleul MD

Purpose

To describe characterstics of the elastic map for focal hepatic lesions assessed by Shear

Wave Elastography (SWE).

Materials and Methods An ultrasound system with SWE capability (Aixplorer® , Supersonic Imagine) was used

to obtain quantitative 2D maps of elasticity including focal lesion and adjacent

parenchyma. Our study included 161 hepatic lesions in 108 patients (59 mens, 49

womens) with 26 hemangiomas, 19 focal nodular hyperplasia (FNH), 11 adenomas, 32

hepatocellular carcinomas (HCC), 60 metastases, 7 cholangiocarcinomas. Tumor

heterogeneity was assessed on the elasticity 2D maps. Tumor and parenchymal elasticity

values were quantified. The Wilcoxon ranksum test was used for statistical analysis.

Results Median value of elasticity (stated in kPa) was 13.1 for hemangiomas, 31.4 for FNH, 8.7

for adenomas, 10,9 for HCC, 57 for cholangiocarcinomas and 27.3 for metastases.

Parenchymal elasticity values were 7,7 for normal liver and 28,5 for cirrhotic liver. On 2D

elasticity maps, FNH lesions had high central elasticity values.

Conclusions SWE gives additional information about focal hepatic lesions. Cholangiocarcinoma and

FNH exhibited high elastic values, likely due to fibrosis. Metastases values were highly

variable , depending on primitive's histopathological type. HCC, adenoma and

hemangioma exhibited intermediate values. Concerning the adjacent parenchyma, the

elevated elastic value in livers with HCC could be useful for the diagnosis.

Clinical Relevance/Application The Shear wave elastography could be usefull to diferentiate FNH (hard lesion) and

adenoma (soft lesion) or cholangiocarcinoma (hard lesion) and HCC (soft lesion).



ABDOMINAL


RSNA 2011

Quantification of the Kidney Fibrosis Using Supersonic Shear Wave Imaging: Experimental Study with Rabbit Model SK Moon, DH Lee MD, SY Kim MD, JY Cho MD, SH Kim, KC Moon.

Purpose To evaluate the values and feasibility of ultrasonic shear wave elastography for the

quantification of renal fibrosis in an experimental rabbit model.

Materials and Methods Thirty-eight kidneys of 19 rabbits were studied and categorized into three groups;

hydronephrosis group, renal vein thrombosis group and normal control group.

Hydronephrosis (n=9) and renal vein thrombosis (n=10) was surgically made in each left

kidney. Their right kidneys were control group (n=19).We repeatedly measured

viscoelasticity (Young’s modulus, kPa) at renal cortex using shear wave elastography and

evaluated sonographic findings of each kidney; size, echogenicity, other pathology,

perfusion degree, and resistive index (RI) measurement before operation, on 1st day

after operation, 3rd day, and weekly until 2nd week in hydronephrosis group, and until

4th week in vein thrombosis group. After sacrifice of the rabbits, degree of histologically-

quantified fibrosis and measured viscoelasticity was statistically compared.

Results

Before surgery, initial mean viscoelasticity of renal cortex and conventional US findings in

three groups showed no significant difference (p> 0.05, 9.74kPa in control, 8.95kPa in

hydronephrosis, and 9.06kPa in thrombosis). However, in the last US exam, mean

viscoelasticity in each group were significantly different (p= 0.01, 9.77kPa in control,

10.91kPa in hydronephrosis, and 13.92kPa in thrombosis). Pathologically, degree of

fibrosis was significantly different among three groups (p< 0.001, 0.70% in control,

3.62% in hydronephrosis, and 11.70% in thrombosis), and the fibrosis degree and

viscoelasticity showed statistically good correlation (rho= 0.568, p= 0.01). In addition,

mean kidney size of the thrombosis group was significantly decreased as compared with

other two groups (p = 0.01). Of 39 kidneys, 19 control group kidneys had no fibrosis (<

1.5%, 0.70%), 12 minimal fibrosis (1~10%, 4.48%), and 7 mild fibrosis (> 10 %,

13.70%). In the prediction of fibrosis more than 10%, shear wave elastography showed

sensitivity 100% and specificity 87.1% at a cut-off value of 12.80kPa.

Conclusions Ultrasonic shear wave elastography showed good correlation between viscoelasticity and

histologic degree of renal fibrosis. It can be the feasible tool in quantification of the renal

fibrosis.

Clinical Relevance/Application Ultrasonic shear wave elastography can be the noninvasive tool for the prediction of the

renal interstitial fibrosis.



PROSTATE


RNSA 2011

Transrectal Ultrasound Quantitative Shear Wave Elastrography : Application to Prostate Nodule Characterization – A Feasibility Study J Correas, MD,PHD; A Khairoune; A Tissier, MD; V Vassiliu, MD; A Méjean, MD,PhD; O Hélénon Necker University Hospital, Paris, France

Purpose The purpose of this study was to evaluate the feasibility of real time TransRectal

UltraSound (TRUS) quantitative Shear Wave Elastography (SWE) imaging for prostate

lesion characterization.

Method and Materials 31 patients presenting increased PSA values (4-10 ng/mL) were prospectively enrolled

after signing an informed consent form. The prostate was studied using trans-rectal

ultrasound (TRUS) with spatial compounded B-mode, Color Doppler UltraSound (CDUS),

and SWE with an Aixplorer ultrasound system (Supersonic Imagine, Aix-en-Provence,

France). Elasticity measurements in KiloPascal and ratios between nodules and adjacent

parenchyma were calculated. Contrast-Enhanced US (CEUS) was performed using low MI

pulse subtraction after injection of 4.8 ml of SonoVue® (Bracco, Milan, Italy). Imaging

findings were correlated to sextant prostate biopsies (n=12) and targeted biopsies on

suspicious areas (n=2-6) detected at SWE and CEUS. MRI with axial and coronal T2w

acquisition, axial T1w acquisition, diffusion and dynamic contrast-enhanced MRI was also

evaluated.

Results Among the 39 nodules detected either at ultrasound imaging or at pathology, 14 were

adenocarcinomas with Gleason score above 6 and 25 were adenomatous hyperplasia or

focal prostatitis. Prostate cancer nodules exhibited higher stiffness (mean 58±48 kPa)

than the adjacent peripheral gland (mean 20±10 kPa). The stiffness ratio between

nodule and adjacent parenchyma was significantly higher for cancer (3.0±1.0) compared

to benign nodules (1.0±0.20; p< 0.01). The ratio cutoff value of 1.5 allowed the best

discrimination of the two populations. The Sensitivity (Se), Specificity (Spe), Positive

Predictive Value (PPV) and Negative Predictive Value (NPV) were calculated for each

modality: CDUS, CEUS, SWE ratio (with 1.5 cutoff) and MRI. CDUS: Se= 55%; Spe=

76%; PPV= 55%; NPV= 76%. CEUS: Se= 70%; Spe= 80%; PPV= 70%; NPV= 80%.

SWE ratio: Se= 85%; Spe= 90%; PPV= 85%; NPV= 90%. MRI: Se= 73%; Spe= 75%;

PPV= 56%; NPV= 82%.

Conclusions TRUS SWE has large potentials for the characterization of prostate nodules. These

preliminary results must be confirmed by a multi centric clinical trial.


RSNA 2011

Shear Wave Imaging of the Prostate RG Barr MD, PhD

Purpose / Aim To review the technique and interpretation of shear wave elastography of the prostate

Content Organization A. Review Principles of shear wave elastography B. Provide detailed technique of

performing the endo-rectal shear wave prostate examination C. Discuss artifacts and how

to eliminate them D. Compare shear wave images of the prostate to whole mount

pathologic slides in patient who have undergone total prostatectomy. Histopathologic

correlation with ultrasound examination including shear wave is used to emphasis

education of this technique. E. Provide guidelines for image interpretation

Summary Shear Wave elastography of the prostate is a new developing technique that holds

promise for improved lesion detection and characterization. This exhibit reviews: a.

Principals of shear wave elastography with emphasis on prostate imaging b. Technique of

performing the examination c. Provides a pictorial essay comparing shear wave finds to

pathology specimens d. Provides guidelines for intrepretation



MUSCULOSKELETAL


RSNA 2011

Range of Normal Value of Muscular Stiffness Measured by Shear Wave Elastosonography C Bortolotto MD, A Presazzi MD, L Lungarotti, M Zacchino, FDraghi MD, F Calliada MD, M Canepari MD

Purpose To determinate a range of normal muscular stiffness value and its variations due to

individual physiologic body differences and technical factors.

Materials and Methods Fifty-four healthy and young volunteers (mean age 23 years; range 18-31) were

recruited. Muscle stiffness was bilaterally measured on relax and contraction of femoral

biceps and gastrocnemius using shear wave elastosonography (SWE) scanner

(Supersonic Imagine; Aix En Provence; France). Every muscle was measured twice (ROI

diameter was chosen of 2 and 4 mm). Measurements were taken blind by three different

radiologists. Predominant limb and level of physical training were assessed by a

questionnaire. Volunteers were divided in 3 different levels of training.

Results The mean stiffness value resulted 2,07 m/s ±0,40 SD for femoral biceps and 1,89 m/s

±0,43 SD for gastrocnemius. After contraction this value became higher: 2,76 m/s ±0,74

SD for femoral biceps and 2,53 m/s ±0,74 SD for gastrocnemius. No significant

differences (p-value >0.05) neither on relaxed muscle nor during contraction emerged

among people with different levels of physical activity, between right and left side and

between both sexes. Furthermore, different operators and ROI’s diameter demonstrated

to be irrelevant in evaluating muscle stiffness (p-value >0.05). Statistically significant

variations in stiffness (p-value <0.05) resulted only evaluating different muscles or,

considering the same muscle, between relax and contraction.

Conclusions SWE seems not influenced by physiologic factors such as sex, predominant limb and

levels of physical activity. Also, technical factors not influenced the results: different ROI

dimensions and inter-operator variability had no significant influence on measurements.

Only different muscle anatomy determined statistically different SWE values.

Compared to other studies, our results allow to quantify a range of normal muscle

stiffness establishing a possible point of reference to asses muscular pathology.

Moreover this value seems not influenced by physiological and technical factors.

Therefore, a significant increase in muscle stiffness, measured with SWE, needs to be

investigated as a possible expression of muscle pathology.

Clinical Relevance/Application We quantitatively defined the range of normal muscular stiffness establishing a landmark

to asses muscular pathology, and demonstrate that physiological/technical factors don’t

influence measurement.



GYNECOLOGY


RSNA 2011

ShearWave™ Ultrasound Elastography of the Uterine Contraction during Labor O Ami1 MD, PhD, M Mabille1 MD, JL Gennisson2 MD, PhD, J De Laveaucoupet1 MD, M Tanter2, R Frydam1, D Musset2 MD. 1University Hospital, Paris, France; 2Institut Langevin, Paris, France

Purpose During childbirth and labour, the measurement of the intensity of uterine contractions is

paramount to understanding the underlying mechanisms of the so called “uterine motor”.

The reference method normally used to evaluate this intensity consists in a measurement

by a pressure sensor placed on the uterine fundus.

We present the initial results of a pilot study on the evaluation of uterine contractions

with ShearWave ultrasound elastography, its feasibility, and its potential interest.

Method and Materials The SHEARWAVE ultrasound elastography was performed with a AIXPLORER v2

ultrasound platform with an abdominal high frequency linear probe, commercially

available since 2009 (Supersonic Imagine, France).

The elastography measurements were performed when the myometrium and fat tissue

represented more than two thirds of the screen. The elastographic modulus centered on

the myometrium was compared to the external pneumatic tocogram, given in mmHg.

The correlation between the elastographic modulus and the data obtained with the

pneumatic tocogram was estimated using the Spearman correlation coefficient.

Results

Sixteen patients were observed during a period of uterine relaxation or contraction,

totalising 104 measurements, of which 52 were during contraction and 52 during

relaxation.

The elastography modulus during relaxation ranged from 7 to 31 KPa, with a mean value

of 18 KPa. During contraction, the elastography modulus ranged from 38 to 96 KPa, with

a mean value of 63 KPa. The correlation coefficient between elastography modulus and

tocogram was r = 0.98, p<0.00001. The Student t paired test showed a significant

difference between the two states of the uterine muscle with an elastographic modulus

aproximately 3 times greater during contractions than during relaxation (p < 0.00001).

Conclusions

SHEARWAVE ultrasound elastography allows the visualization of uterine contraction, its

distribution, and the evaluation of its strength.

To our knowledge, it is the first time that the uterine contraction phenomenon has been

visualized directly and quantified with an imaging technique.

Clinical Relevance Precision and reproducibility of the measurement compared to the reference method

during labor is promising to help measuring uterine contractions in small terms or

extreme premature labor threats.


posters and oral presentations on s w e rsna 2011

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