Noninvasive quantitative assessment of microcirculatory disorders of the upper extremities with 2D fluorescence optical imaging

BACKGROUND: Quantitative Imaging of microcirculatory disorders is challenging. OBJECTIVE: To investigate the feasibility of 2D Fluorescence Optical Imaging (FOI) for characterization and quantification of microcirculatory disorders in peripheral arterial occlusive disease (PAOD) of the upper extremity. METHODS: 9 patients with various clinical presentations of PAOD of the upper extremity were included. Quantitative analysis of both hands was performed by assessing the fluorescence intensity of Indocyanine Green (ICG) dynamically over a time period of 360 seconds. Analysis of the signal intensity within multiple regions of both hands was calculated and time-dependent perfusion curves for each region of interest were plotted over time. RESULTS: Compared to the healthy, vascular non-impaired segments, pathological segments with an impaired tissue perfusion were identified through a decreased rate of early tissue enhancement (p = 0.02) and increased signal intensity of the optical perfusion agent per second (p < 0.001). The affected segments showed a decreased maximum signal intensity and a prolonged interval to reach the maximum signal intensity (time to peak). CONCLUSION: 2D FOI allows quantitative assessment of the peripheral microcirculation in various vascular pathophysiologies and is able to detect the impaired tissue perfusion in patients with vascular disorders of the upper extremity.