Quantitative Ultrasound (QUS) Considerations · QUS-based imaging, in its most general sense, is...

Quantitative Ultrasound (QUS)

William D. O’Brien, Jr.

Bioacoustics Research Laboratory

Department of Electrical and Computer Engineering

University of Illinois, Urbana, IL

Support: R01 CA111289

AAPM, August 2, 2011

ConsiderationsModel-based concept

Physical phantoms (validation steps)

Biological phantoms (CHO, 3T3)

3-tumor comparisons (FA, 4T1, EHS)

Further comparisons (4T1, EHS)

Cross-platform comparisons (4T1, MAT)

Some final thoughts







Some final thoughts

QUSModel-based imaging, in its most general sense, is the application of a priori (known or assumed) information to augment in vivoacquired image-based data.

The cellular-level and tissue-level information is being modeled mathematically to represent microanatomical scatterers.







Some final thoughts

Biological Phantom: Cell Model

Biological Phantom: CHO sizes

CHO Nucleus Radius: 3.3 µm

CHO Cell Radius: 6.7 µm

Biological Phantom: CHO

CHO: 490

Mcells/mL

CHO: 230

Mcells/mL

Biological Phantom: CHO Results

Biological Phantom: 3T3 Results

Conclusions, for now

The concentric sphere model shows good quantitative agreement with the BSC measurements for both CHO and 3T3 cell pellets at low cell concentrations (volume density < 10%).

The concentric sphere model is able to predict the size and impedance –statistically speaking -- of both cell nucleus and cytoplasm at low cell concentrations.







Some final thoughts

Light Microscopy ComparisonsFibroadenoma Carcinoma (4T1) Sarcoma

(EHS)

Acini ≈ 100 µm More uniform Clumped cellular

distribution structures, less

of scatterers uniform scattering

Feature analysis shows distinctions between the three

kinds of tumors

QUS Size Images (Scatterer Diameter)

Fibroadenoma Carcinoma Sarcoma







Some final thoughts

Further: Modeling a Cell & Tissue

Parameters varied in fit: gain factor (between

measured and model curves), the ratio of the total

cell diameter to nuclear diameter (RC / RN), nuclear

radius (RN), nuclear impedance (I0), and maximum

cytoskeletal impedance (I1).

Further: 4T1 & EHS

Carcinoma: ●; Sarcomas: ■

Further: 4T1 & EHS

Carcinoma: ●; Sarcomas: ■


Conventional models were not adequate to separate the carcinoma from the sarcoma.

New models were constructed that yielded separation of the carcinoma from the sarcoma.

Multiparameter approaches suggest better classification of tissues







Some final thoughts

Cross-platform Capabilities

Demonstrate feasibility of in vivoarray-based system-independent measurements of:

Attenuation

Backscatter coefficient


Ultrasonix RP system

5, 7.5 and 15 MHz linear arrays

Siemens Acuson S2000

9 and 15 MHz arrays

Zonare Z.one

7 and 10 MHz linear arrays

VisualSonics Vevo2100

15 MHz linear array

40 MHz linear array for 3D images



4T1 mouse mammary carcinoma

BALB/c mice

17 - 4T1 tumors

6.3 – 620 mm3

MAT B III rat mammary adenocarcinoma

Sprague Dawley rats

10 - MAT tumors

12– 3100 mm3

Cross-platform Capabilities –4T1

D = 5.2 mm

5.6 x 6.0 x 4.6

D = 10.6 mm

12.8 x 8.2 x 12.5

Cross-platform Capabilities -MAT

D = 10.4 mm

15.6 x 12.2 x 6.4

D = 2.9 mm

5.2 x 3.4 x 1.5


V = 102 - 103 mm3 => D = 5.8 - 12.4 mm


Reasonable agreement obtained across imaging platforms.







Some final thoughts

Final Thoughts, for now

Cell- and tissue-based studies allow the development of techniques for constructing better models to quantify tissue microstructure.

Challenges remain to quantify tissue microstructure, but we are having some success.

Thanks

Quantitative Ultrasound (QUS) Considerations · QUS-based imaging, in its most general sense, is...

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