Simultaneous Blood Flow Measurement and Dermoscopy of Skin Lesions Using Dual-Mode Dermascope

Abstract

Dermascopes are commonly utilized for the qualitative visual inspection of skin lesions. While automated image processing techniques and varied illumination strategies have been used to aid in structural analysis of lesions, robust quantification of functional information is largely unknown. To address this knowledge gap, we have developed a compact, handheld dermascope that enables real-time blood flow measurements of skin during conventional visual inspection. In-vitro characterization demonstrated that the dermascope is capable of quantifying changes in flow across a physiologically relevant range even when used in a handheld manner with clinic lighting and dermascope LEDs on. In a small pilot clinical study, we demonstrated the dermascope's ability to detect flow differences between two distinct lesion types.

Figure 1

Average speckle contrast of LSCI images acquired using the LSCI-dermascope from a tissue phantom with room lights and tissue illumination LEDs on/off. Neither light source affected measurements collected with the LSCI-dermascope.

Figure 2

Average speckle contrast from a tissue phantom acquired from the LSCI-dermascope in a handheld and mounted configuration. These data suggest that handheld operation of the LSCI-dermascope did not affect measurement accuracy.

Figure 3

(A) Experimental setup used to characterize the response of LSCI measurements acquired with the LSCI-dermascope to varying flow rates within a simulated blood vessel embedded in a tissue phantom. The dotted line shows the approximate measurement area and location of the LSCI-dermascope cone. (B) Average speckle contrast within the area shown in (A) from a region above the tube (dynamic region) and a region not above the tube (static region) for known volumetric flows of Intralipid. Error bars represent standard deviation between measurements.

Figure 4

(A) Representative dermascope image of cherry angioma with corresponding blood flow map (B). (C) Representative dermascope image of solar lentigo with corresponding blood flow map (D). Scale bars in (A) and (C) are 1 mm. Dashed lines in (B) and (D) show region of interest selected for data averaging. Colorbars in (B) and (D) are in units of speckle flow index. (E) Average blood flow relative to surrounding normal skin for all LSCI-dermascope measurements collected from solar lentigos and cherry angiomas. Error bars represent standard deviation between average measurements.

Figure 5

(A) Photograph of the LSCI-dermascope. (B) Cutaway drawing of the LSCI-dermascope illustrating the internal components that enable simultaneous LSCI measurements and conventional dermoscopy.