In Vivo Fluorometric Assessment of the Skin Microcirculation

A tissue uptake model was developed to describe the fluorescein dermofluorometer signal in terms of the local blood flow and capillary permeability. The fluorescein signal is characterized by a wash-in time constant dependent on both the blood flow and permeability. Under flow-limited conditions the wash-in time constant is inversely proportional to the blood flow only. Significant differences in the fluorescein wash-in time constant were measured between diabetic and non-diabetic subjects (p < 0.10) and between diabetic patients with chronic foot ulcers and those without ulcers (p < 0.01). A new technique, dual dye dermofluorometry, which measures the simultaneous signals from an intravascular tracer, indocyanine green, and a diffusible tracer, sodium fluorescein, was developed. The indocyanine green signal is described by a physiologically-based pharmacokinetic model with a wash-in time constant inversely proportional to the blood flow. The extravascular fluorescein signal is extracted from the observed signal by subtracting a scaled version of the indocyanine green signal. Indocyanine green wash-in time constants were significantly different between patients whose foot ulcers led to amputation relative to those whose foot ulcers healed without surgery (p < 0.10) and between patients with past foot ulcers relative to patients with no history of foot ulcers (p < 0.05). It was determined that while the flow-limited assumption for fluorescein was valid in healthy rat skin, it was not valid in diabetic subjects.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biophysics and Computational Biology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Oh, Deborah Kyung

Contributors dc:contributor

• Richard L. Magin

• Engineering, Biomedical

Language dc:language

eng

Identifier

(MiAaPQ)AAI9944955

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/85491