Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


A Comparison of Optical Coherence Tomography and Clinical Assessment of Nail Disease in Psoriasis and Psoriatic Arthritis.

Castillo-Gallego1,  Concepcion, Aydin2,  Sibel, Ash3,  Zoe R., Abignano3,  Giusepinna, Emery3,  Paul, Marzo-Ortega3,  Helena, Del Galdo3,  Francesco

Hospital Universitario La Paz, Madrid, Spain
Goztepe Training and Research Hospital, Istanbul, Turkey
University of Leeds, Leeds, United Kingdom

Background/Purpose:

Nail disease in psoriasis (Pso) is increasingly recognised to be of major clinical and research relevance. Clinical assessment is the only currently available tool and no objective methods have been standardized to image the nails. Optical coherence tomography (OCT) is an analogue of ultrasound, using infrared light instead of acoustic waves and has been used in the clinical setting by ophthalmologists since 1991. The axial resolution is determined by the bandwidth of the light source, which is 1–2 mm in general, limiting its use to very superficial tissues. It has also been widely investigated in dermatology, particularly in non-melanoma skin cancers.

The purpose of this study was to describe nail appearances as seen with OCT and to compare these findings in Pso and psoriatic arthritis (PsA) with clinical assessment.

Methods:

A total of 290 finger nails of 17 patients (4 Pso, 13 PsA) and 12 healthy controls (HC) were scanned by OCT with a topical probe "VivoSight" ( Michelson Diagnostics) and optics of Swept-source Fourier-Domain type with a laser wavelength of 1305+/- 15 nm. The investigator was blinded to the clinical details.

Signal changes within the nail and contour abnormalities by OCT were documented. Clinical nail abnormalities were independently scored by an assessor blinded to the OCT findings using the mNAPSI scoring system.

Results:

OCT showed remarkably high quality images of the nail, the adjacent nail matrix and the subungual epidermis. The most striking finding was that of leukonychia, manifesting as diffuse "white" lines running obliquely along the middle third of the nail. Pits were remarkably superficial and were associated with disorders of the nail matrix keratinisation. Subungual vascularity and subungual epidermis hyperplasia could be delineated.

The mean (SD) age of patients was 54.4 (16.5) and 29.4% of them were female. The overall mean (SD) modified NAPSI scores was 12.8 (10.6) for patients with 94% (16/17) having at least one involved nail by OCT. The number of involved nails by OCT was significantly higher in patients compared to HC (median (range): 7 (0–10) vs. 1 (0–6); p=0.001)). When analysed per nail, patients had significantly higher number of involved nails by OCT compared to HC (106/170 (62.4%) vs. 22/120 (18.3%); p<0.0001). The absolute agreement between OCT and clinical assessment was 69.3%. Within patient group, OCT detected abnormalities in 33 nails (19.5%) where clinical assessment was normal.

Having a positive OCT (either signal changes or contour abnormalities) had a sensitivity and specificity of 57% and 82%, with a likelihood ratio (LLR) of 3.1 for a diagnosis of Pso. When different findings of OCT were compared, large intra-nail plate linear "calcifications" and superficial hyperkeratinisation of the nail had the highest LLRs (16.2 and 6.4, respectively). None of the HC had clinical nail disease whereas 9/12 (75%) of them had at least one involved nail by OCT.

Conclusion:

These preliminary findings clearly show that OCT has great potential for the systematic characterisation of nail changes in Pso and this could have implications for diagnosis, prognosis and monitoring of therapies.

To cite this abstract, please use the following information:
Castillo-Gallego, Concepcion, Aydin, Sibel, Ash, Zoe R., Abignano, Giusepinna, Emery, Paul, Marzo-Ortega, Helena, et al; A Comparison of Optical Coherence Tomography and Clinical Assessment of Nail Disease in Psoriasis and Psoriatic Arthritis. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :200
DOI:

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