A new nailfold capillarocsopy system

The video above shows a brief overview of our new system for acquiring nailfold video sequences, that are processed into high-quality static mosaic images and used to compute measures of capillary structure and blood flow.
Further details of the process are given below, and can also be found in our 2016 MICCAI paper (see key publications below). .

Nailfold capillaroscopy is technique used to capture images of capillaries in the fold of skin immediately below the fingernail (the nailfold). Here the capillaries lie parallel to the skin and can be visualised using visible light (with green light providing the best contrast between red blood cells and the surrounding the tissue). As such the nailfold capillaroscopy provides a non-invasive, cost-effective method of visualising the human microvasculature system in real-time.

It may be used in many clinical situations, but is particularly helpful in diagnosing and tracking the progression of connective diseases that affect the structure and function of capillaries.

The video below shows a screen grab of the new system in use during a live recording session. The user controls the 3D motorised platform to which the camera is connected by moving an onscreen joystick or clicking to where they wish move next in the live-view. Arrow keys or the mouse-wheel move the platform vertically to enable fine-tuned focus. The camera may also be autofocused by pressing the space-bar or double clicking a location in the live-view. During recording a real-time mosaic of the frames is displayed. When recording stops the full sequence of frames are automatically processed to improve the quality of the mosaic, selecting only in-focus frames at each spatial location.

The 3D platform can itself be tilted and locked at any angle from its default vertical position to near-horizontal using a motorized actuator, so that the focus plane of the camera can be rotated through approximately 75 degrees. This enables the imaging of patients with contractures that prevent them from placing their fingers flat against the support platform.

Measuring blood flow

We completed an initial trial of the new system, imaging 112 subjects (50 SSc, 12 Primary Raynaud's phenomenon, 50 healthy controls). Details of this study are given in the MICCAI 2016 paper and will shortly be published in a clinical journal.

Key publications

1. Berks et al, Improved diagnosis of systemic sclerosis using nailfold capillary flow, MICCAI, LNCS 9902:10.1007/978-3-319-46726-9_40, 2016
2. Berks et al, An Automated System for Detecting and Measuring Nailfold Capillaries, MICCAI, LNCS 8673:658-6655, 2014
3. Murray et al, Non-invasive Imaging Techniques in the Assessment of Scleroderma Spectrum Disorders, Arthritis Care and Research, 61(8), 2009