Medical Ultrasound Measurements

Lab Tour

May 2011 1

Ultrasound (US)Signal processingImage processingMultiple medical imaging modalities registrationClinically significant evaluative tools

Cardiac functionNeovascularization

Therapeutic ultrasoundAcute Cardiac Pacing by High Intensity Focused US

Research Highlights

May 2011 2

A feature dependent approach for improving speckle noise reduction and side lobes

suppression in ultrasound images

• Frequency compounding is applied to selected regions in the image and avoided from others, depending on the identification of features for which preserving the axial resolution is of high importance. Such features are point reflectors, lesions boundaries and cysts boundaries.

• Apodization is applied only at specific regions in which side lobes are identified.

May 2011 3

Feature dependent compounding

Reference image

Ordinary compounding Local optimum compounded image

Selective Local optimum compounded image

Scan image (2nd harmonic) - reference (no apodization

Scan image (2nd harmonic) - with ordinary Hanning apodization

Scan image (2nd harmonic) - side lobe suppressed by selective apodization

Ordinary apodization

Feature dependent apodization

May 2011 4

Speckle Tracking Echocardiography

May 2011 5

A Small Endocardial Myocardial Infarction

May 2011 6

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35-20

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Time [sec]Glo

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Y [c

m]

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Wavelets Based Detection

May 2011 7

Automatic detection of left ventricular anatomic features: Mitral valve

Continues Valve Corner Tracking

Automatic Left Ventricle Segmentation Algorithm

יד שמאל

יד ימין

מבט מכיוון כפות הרגליים

רקמת שומן -בטן

ריאה שמאל

ריאה ימין

חדר שמא

לחדר

ימין

עמוד שדרה

גב

עצם יד שמאל

עצם יד ימין

שריר הלב

זרימת דם לתוך החדר

מסתםגיד שמושך

את העלה של המסתם

מציאת הגבול הפנימי של חדר

שמאל לאורך פעימה שלמה –

לצורך מדידות קליניות ו/או

התאמה להדמיות

אחרות

Registration of Ultrasound and MR Cardiac Images

• Given a collection of segmented ultrasound (US) and MR cardiac images, our challenge is to register or align them

• There are several factors that make this task difficult:– The heart is constantly in motion– The images are almost certainly not of the same slice– Segmentation of the US images is very difficult due

to poorer image quality

May 2011 15

Procedure

• Find the correspondence between homological points

May 2011 16

Procedure Continued

• The US image is: rotated, translated, scaled, and finally “warped” to bring the two contours into alignment

May 2011 17

Arterial tree reconstruction of neovascularization

inside a carotid plaque

May 2011 18

Clinical Motivation

Atherosclerosis

Calcification Inflammation

Unstable Plaque Stable Plaque

Plaque rupture

Stroke and TIA

:The disease

:Atherosclerosis Progression

:Plaque’s content

Pathological result:

Clinical result:

:Plaque’s types

IMT ThickeningPlaque Generation

May 2011 19

• Develop noninvasive quantitative measures of carotid plaque vulnerability,

using Ultrasound Contrast Agents

• Assess the neovascularization phenomena in relationship to inflammation

processes and compare to histological indices

Objectives

Methods

• Using Ultrasound IU22 Philips machine

• Using ultrasound contrast agents

• Developing algorithm for data analysis

• Validating the algorithm – Manual / Visual analysis or histology analysis

May 2011 20

Results

Frame no.1 Frame no.30

Saturationartifacts

In-planevessels

out-planevessels

Intra-plaque neovascularization paths

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

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6x 10

-3

Intra-plaque area of neovascularization / plaque area - US

Are

a of

neo

vasc

ular

izat

ion

/ pla

que

area

- H

isto

logy

Area of neovascularization Vs. Area of the plaque – comparison to histology

Tracking after objects inside the plaque

May 2011 21

Tumor Vascularization Quantification

May 2011 22

Tumor Vascularization Imaging - Current researchQualitative estimation of blood flowDynamic contrast-enhanced ultrasonography (DCE-US)

Contrast-Enhanced Gray-Scale Ultrasound

Zhou et al. , 2011 control treated

Lassau et al. , 2010

23May 2011

3D Structural Quantification

Quantification using 3D segmentation and Displaying using surface rendering:

Improved resolution using 2D Deconvilution Holzman-Gazit, Goldsher, Kimmel 2006http://www.visualsonics.com/vevo2100

Michailovich, Adam, 2005

24May 2011

Extracorporeal Cardiac Pacing by High Intensity Focused Ultrasound Possible Application

Emergency Medicine Cardiac Arrest

Resynchronization Therapy Electrode Implantation Site Evaluation

May 2011 25

Extracorporeal Cardiac Pacing by High Intensity Focused Ultrasound

HIFUMulti Element

Dual Phase SequenceMultiple FrequenciesAccentuated

RareficationAccentuated Pressure

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x 10-6

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2Accentuated Rarefication Pattern

time [sec]

RLU

0 1 2 3 4 5 6 7 8 9

x 10-6

-2

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4Accentuated Pressure Pattern

time [sec]

RLU

May 2011 26

System HighlightsSubjects

Whole AnimalsIsolated Hearts

Monitoring by US Imaging

TimingEvaluation

ECGBlood Pressure

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Time [msec]

Vol

tage

[v]

Pressure ECG Trigger

A. Roytberg, “Study of Efficient Pacing of the Myocardium using External High Intensity Focused Ultrasound,” MSc, Thecnion, 2009.May 2011

27

ThanksProf. Dan AdamNoa Bachner Ph.D.Yael Petrank Ph.D.Amit LivnehAssaf HoogiYossi TsadokAvinoam Bar ZionHanan KamisLiron ShlomoRan MaromTzvi Goldman

May 2011 28

QuestionsThank you.

May 2011 29