Transcript Acknowledgements

Advisor
Client
Justin Williams, PhD
Fredrick Kelcz, PhD, MD
Department of
Biomedical
Engineering
Department of Radiology
University of
Wisconsin-Madison
University of
Wisconsin-Madison
Abstract
Core biopsy procedures are currently subject to high
specificity due to inaccurate imaging of small tumors
around the biopsy needle. Ultrasonic imaging can
differentiate between tissue types by the differences in
echogenic calcifications. The basics of IVUS probes
were used to develop two ultrasonic methods: an
integrated ultrasonic probe and a catheter based IVUS
probe technique. The chosen design involves the
insertion of a catheter based IVUS probe, once the
needle is in place. This technique should provide
accurate imaging and is extremely practical to
implement. However, this techniques will require
further experimentation to evaluate its ability to image
within the needle in the presence of a strong magnetic
field.
Problem Statement
The goal of this project is to develop an
intravascular ultrasonic probe (IVUS) to
provide better imaging without artifact
during mammographic and MRI guided
biopsy procedures. Usually Biopsy
procedures are done with MRI or CT
guidance; however, biopsy needles can
obstruct imaging of tumors making it
difficult to make fine adjustments in
needle placement.
Problem Definition
 Motivation
The accuracy of the overall
biopsy procedure is improved
and doctors can guarantee
patients that the correct lesion
was sampled
Background on Guided
Core Biopsy Procedure



First visit
 Initial mammographic/MR image
 Positive diagnosis—suspicious lesions
Second visit
 Second MR image—insertion of plastic clip
 Third MR image—check placement
 Needle Insertion
– Exact location never verified
 Perform biopsy
Results
 Pathological analysis
IVUS Probes



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Use a pizoelectric transducer implanted in
catheter 1-2mm in diameter and 100-130cm
long
Provide 2D cross sectional imaging
A motor rotates the transducer at ~1800rpm
Typically single use costing ~$1000
Operate at 20-40MHz depending on model
Imaging depth of 1-2cm depending on
frequency
Design Criteria



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Spatial resolution approximately 0.51mm
Depth perception approximately 3-5mm
Distinguish small tumors and
calcifications from normal tissue
Operate within core biopsy needle with
minimal artifact
MRI compatible (Class III)
Final Design:
Catheter Based IVUS Probe

40 MHz “Discovery” IVUS probe

Core Biopsy Needle

Manufactured plastic rod insert
Testing Methods

Phantoms
– Water
– Ground orange pulp*
– Orange slice*
– Ultrasonic gel*
– Raw turkey breast*
*With and without simulated calcifications.
To simulate calcifications we used 8 in 1:Sun ripened
fruit mineral treat (22.5-27% calcium content)
Results
Future Work


Testing MRI compatibility
Future phantoms
– Simulated tumor (olive in turkey breast)
– Real specimen

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Investigate different probe frequencies
Investigate probe redesign
Conclusions

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IVUS imaging shows great potential
towards increasing biopsy yields
System is capable of detecting
calcifications
Ability to detect actual tumors is
unknown
Current devices are not MRI
compatible
Acknowledgements
Our team would like to extend thanks
to the following individuals for their
assistance on this design project:
Dr. Frederick Kelcz
Professor Justin Williams
Dr. Tomy Varghese
Dr. Jim Zagzebski
Keith Bourne
References
Diagnosis by Biopsy. 2003. The Breast Center at Southern Illinois
University School of Medicine. Date Accessed: February 9, 2004.
URL: http://www.siumed.edu/breastcenter/diagnosis.html.
Lengyel J, Greenberg DP, and Popp R. Time-Dependent ThreeDimensional intravascular ultrasound. SIGGRAPH 95 Conference
Proceedings, Annual Conference Series, pages 457--464. ACM
SIGGRAPH, Addison Wesley, August 1995
Nissen S. 2001. Coronary angiography and intravascular ultrasound.
Am J Cardiol. 87(4A):15A-20A
Trevino, M. (2003, December 12) Calcifications may be presage
invasive breast cancer. Diagnostic Imaging Online. Retrieved
February 11, 2004 from
http://www.diagnosticimaging.com/dinews/2003121201.shtml
Yock, P., Johnson, E., and David, D. Intravascular
ultrasound:Development and clinical potential. American Journal
of CardiacImaging 2(185)