Development of a Minimally Invasive Method to Quantify Blood Flow in the Dysvascular Transtibial Amputee, 10-R9803

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Principal Investigator
Julie M. Pickard

Inclusive Dates:  04/01/08 – 04/01/10

Background - More than 125,000 amputations are performed in the United States annually with a majority occurring below the knee (transtibial). The Center of Disease Control reports that more than 60 percent of all non-traumatic lower-limb amputations occur in people with diabetes. The mechanical stresses induced by use of a prosthetic system can adversely affect residual limb health. It is well understood that daily use of a lower-limb prosthetic can affect circulation and that inadequate circulation will be detrimental to limb health. Unfortunately, only a limited amount of research has been done to determine the relationship between prosthetic design/fit and circulation. This is in part due to the limitations of current clinical tools.

Approach - Understanding residual limb health such as circulatory changes as a function of socket suspension design will ultimately promote improved designs, prescriptions, and long-term favorable patient outcomes. This research exploits the area of blood flow modeling using positron emission tomography and magnetic resonance imaging to assess limb health in the diabetic amputee. This method will be the first to quantify absolute tissue blood flow in the lower extremity of amputees and will be novel in that the patient can wear a socket during data acquisition. The model will be used to compare circulatory changes in patients wearing a vacuum-assisted socket system (VASS) and check-valve socket.

Accomplishments - Preliminary data taken at The University of Texas Health Science Center at San Antonio was used to assess the theoretical application of an indicator dilution curve model. Time, magnitude, and dispersion information regarding the radiotracer's bolus were determined using the fitted model, all which are likely to play an important role in SwRI's study as researchers continue analysis of the data for regional blood flow in the muscles using the proposed Kety-Schmidt model. This model will be used to compare pre-VASS and post-VASS measures of blood flow in the residual limb of the dysvascular transtibial amputee. The investigators are currently collecting additional data for analysis.

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