Optical coherence tomography: a reliable alternative to invasive histological assessment of acute wound healing in human skin?

BACKGROUND: Gold-standard assessment of acute wound healing has traditionally been through histological analysis of biopsied tissue. However, this process is invasive with recognized side-effects. Optical coherence tomography (OCT) is a noninvasive technique generating high-resolution real-time images of cutaneous architecture. OBJECTIVES: To compare OCT with histological assessment of in vivo acute wound healing and ascertain the level of agreement between modalities for measurement of defined cutaneous structures. METHODS: Punch biopsies (5 mm) were harvested from 50 healthy volunteers. Wounds healed by secondary intention until they were re-excised 7, 14, 21 or 28 days later depending on random group allocation. Wounds were assessed weekly for 6 weeks using OCT and compared with histological findings derived from time-matched biopsies. Dimensions of four cutaneous structures were measured using both modalities and the level of agreement was established by Bland-Altman analysis. The mean greyscale value (MGV) of the upper reticular dermis was derived from OCT images at all time points. RESULTS: Both techniques showed anatomical congruity in normal and wounded skin with correlating architectural changes associated with inflammatory, proliferative and remodelling wound healing phases. MGV was significantly increased 6 weeks after wounding (P = 0·001) and may represent a novel measure of wound fibrosis. Despite good association of histomorphometric values with low but consistent bias (range -4·181 to 0·431 μm), Bland-Altman plots demonstrated poor agreement between OCT and histology. CONCLUSIONS: Optical coherence tomography enabled accurate assessment of healing tissue comparable with histological analysis of biopsy specimens. This noninvasive tool is highly suited to wound assessment and may represent a diagnostic alternative to punch biopsies.