Aspiration methods and devices for assessment of viscoelastic properties of soft tissues

Abstract

Methods for assessing viscoelastic properties of soft tissues are based on detecting an inflection point on a pressure-time plot when air is aspirated from a cavity placed over the tissue sample. A small diameter tube through which air aspiration is conducted is ultimately closed off by tissue being drawn into the cavity causing an abrupt change in pressure slope. First or second derivatives of the pressure-time plot can be used to detect the inflection point. Repeating the test with a different aspiration rates or after a predetermined relaxation time allows determining tissue viscosity and tissue creep in addition to tissue elasticity expressed as Young's modulus.

Description

BACKGROUND OF INVENTION[0001]The invention relates to methods and devices for assessing viscoelastic properties of soft tissues. In particular, the invention relates to using aspiration methods to detect elasticity, viscosity, creep and other properties of accessible living tissues such as skin, cervix, vaginal wall, etc.[0002]Mechanical properties of skin (e.g., elasticity of skin) may change due to disease, stress, or dehydration. When the body becomes dehydrated as a result of diseases such as those that cause diarrhea or reduced liquid intake such as famine or marathon running, the skin becomes “doughy” and does not snap back when pinched. In a test for dehydration called the “pinch test” or “turgor test,” the skin is grasped and pulled up in a pinch-like manner and then released. Healthy skin will quickly snap back to its undeformed state, whereas dehydrated skin returns to its undeformed state slowly. Such conventional test is subjective and inaccurate. Objective determination...

AI Technical Summary

Benefits of technology

"The present invention provides novel methods and devices for objective evaluation of viscoelastic properties of soft tissues. The invention includes an aspiration method for measuring soft tissue mechanical properties using a probe with a cavity and a small diameter tube extending inside the cavity. The method allows for comprehensive tissue evaluation beyond determination of tissue elasticity by Young's modulus. The device monitors negative pressure in the probe to identify the inflection point indicating the touching of the end of the tube by the tissue. The invention provides a simple and effective way to evaluate viscoelastic properties of soft tissues."

Problems solved by technology

Such conventional test is subjective and inaccurate.

The occurrence of cervical ripening before 34 weeks of gestation leading to preterm delivery represents a serious medical problem.

Preterm delivery is a major cause of perinatal morbidity and mortality.

Premature babies are at increased risk for newborn health complications, as well as lasting disabilities, such as mental retardation, cerebral palsy, lung and gastrointestinal problems, vision and hearing loss, and even death.

The process of cervical ripening, consisting of softening of the connective tissue components, is not easily identifiable with present methods.

However, the true etiology of prolapse and differences seen among individuals are not entirely understood.

These devices however lack the ability for a comprehensive assessment of tissue which goes beyond simple elasticity measurements.

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