Capillary Refill-The Key to Assessing Dermal Capillary Capacity and Pathology in Optical Coherence Tomography
M J Casper1,2, J Glahn1, M Evers1,2
1Harvard Medical School, Cutaneous Biology Research Center, Massachusetts General Hospital, 149 13th Street, Boston, Massachusetts, 02129.
Lasers in Surgery and Medicine
|November 23, 2019
Summary
A new optical coherence tomography angiography (OCTA) method maps skin capillary networks accurately. This technique introduces Relative Capillary Capacity (RCC) to assess vessel dilation potential and permeability.
Area of Science:
- Dermatology
- Biomedical Imaging
- Vascular Biology
Background:
- Standard optical coherence tomography angiography (OCTA) captures only actively perfused surface microvasculature, not the full vascular network.
- Skin capillary perfusion is dynamic and influenced by physiological needs, limiting standard OCTA's representation of the complete vascular structure.
- Existing OCTA methods provide a snapshot of perfusion, failing to depict the entire extent of the skin's capillary network.
Purpose of the Study:
- To develop an improved OCTA method for accurate anatomic mapping of human skin's surface capillary network.
- To introduce a novel quantifiable parameter, Relative Capillary Capacity (RCC), for assessing capillary dilation potential and permeability.
- To demonstrate the limitations of standard OCTA by highlighting the advantages of the new imaging sequence.
Main Methods:
- OCTA imaging was performed at baseline and after skin compression to capture capillary refill.
- An optimization-based automated vessel segmentation method was employed for image sequence analysis.
- The new RCC parameter was calculated and compared with visual assessments of capillary viability.
Main Results:
- The developed OCTA imaging sequence successfully maps cutaneous capillary networks irrespective of ambient perfusion.
- Comparing baseline and refill images revealed the inadequacy of standard OCTA and validated the new method.
- The Relative Capillary Capacity (RCC) was established as a quantifiable metric for evaluating capillary dilation potential and permeability.
Conclusions:
- The proposed Capillary Refill Method using OCTA offers a more accurate representation of skin vasculature than standard techniques.
- The novel RCC biometric serves as a valuable tool for assessing capillary function.
- Future dermatological diagnostics should consider this enhanced OCTA approach and explore RCC's relevance in differential diagnosis and dermatopathology.
