Calibration of sonographic gel probe covers for in-vivo mechanical testing

Cervical insufficiency is a condition in pregnancy in which the cervix asymptomatically dilates in the absence of uterine contractions, resulting in a spontaneous preterm delivery. The condition is often misdiagnosed and presents a significant challenge for the clinical community. In order to establish better diagnostic criteria for cervical insufficiency and to improve assessment of preterm delivery risk for the individual patient, a non-invasive medical imaging tool, which uses ultrasound elastography to test the mechanical properties of cervical tissue, has been developed. The hand-held ultrasound indentation system will enable in vivo collection of stress-strain data from patients that will provide researchers with the necessary information to be used in material modeling and improve diagnosis of cervical insufficiency. The device consists of an ultrasound probe, enclosed by a gel-filled cover. The mechanical properties of the covers vary with each cap as well as with time and temperature. Therefore, in order to ensure accurate measurement, the probe covers must be calibrated prior to use. An experimental study was carried out to examine the effects of various testing conditions on the mechanical behavior of the probe covers. Different freezing and thawing techniques were explored in order to determine favorable conditions in order to preserve the integrity of the probes between the time of manufacture and actual use. From the results of the research, the appropriate combination of testing conditions for probe calibration was determined, as well as freezing and thawing techniques for probe preservation.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Charenkavanich, Panasaya

Advisor dc:contributor.advisor

• Simona Socrate.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/32870

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/32870