Imaging Oximetry of Peripheral Ischemia for Identification of Amputation Level


To develop an easy to use, low-cost, noninvasive portable device that can measure local tissue oxygenation and help guide surgeons in performing lower limb amputations

Anticipated Impact: 

Improved outcomes following limb amputation; prediction and monitoring of healing of diabetic foot and pressure ulcers


Approximately 150,000 non-traumatic lower extremity amputations are performed in the U.S. each year; diabetic patients account for over 50% of these. The annual cost of lower extremity amputations due to diabetes alone is more than $1.5 billion. Diabetic patients are also more likely to require re-amputation to a higher level, resulting in additional costs and patient morbidity. The ongoing challenge for surgeons is to balance primary wound healing at the amputation site against maximal limb salvage. Selection of the correct amputation level is essential for maximizing rehabilitation potential and avoiding complicated re-amputations. Current methods for predicting lower extremity amputation level are expensive, invasive, and/or have limited reliability. This project will develop a new device to measure oxygen levels in limb tissue to assist surgeons in locating poorly oxygenated (ischemic) tissues for excision and well oxygenated (perfused) tissues for salvage. In clinical studies, the investigators will assess correlations between the oxygen levels measured by their device, surgeons' choice of amputation level, and post-surgical healing. Although the initial application of this new device is for amputation level selection, it may also be useful for predicting and monitoring healing of diabetic foot ulcers, pressure ulcers in spinal cord injury patients, and surgically created skin flaps. A Washington-based medical device manufacturing company will provide in-kind market research and commercialization support to the project

See also:

Ischemia Imaging for Amputation

Grant Update

Principal Investigator:
Daniel Leotta
Grantee Organization:
University of Washington
Grant Title:
Imaging Oximetry of Peripheral Ischemia for Identification of Amputation Level
Grant Cohort and Year:
2009 Project Grant (01)
Grant Period:
05/01/2010 - 04/30/2013 (Completed)
Grant Amount:
Collaborating Organizations:
DE Hokanson
Optical reflectance variations due to blood volume changes in tissue were recorded with our imaging system. We used these signals to measure tissue oxygenation and to produce two-dimensional maps of regional tissue oxygenation, using a calculation method derived specifically for our system. We tested the method with normal subjects and achieved repeatable results, and we demonstrated variations in tissue oxygenation at different anatomic sites that are consistent with previous reports in the literature. Our system is based on low-cost components, which should extend the availability of non-contact tissue oxygenation measurement to a wide range of health care providers and settings.

Impact in Washington

Location of LSDF Grantee
Locations of Collaborations/Areas of Impact

Legislative Districts:
11, 34, 36, 37, 41, 43, 46, 48

Health Impacts

Ischemia Imaging for Amputation