Can spectral doppler high specificity and gray scale nail assessment suggest inflammation in psoriatic arthritis patients and control groups?

Introduction: The use of high resolution ultrasonography (US) has become a very important tool in nail assessment. This study evaluated nails clinical and ultrasound measurements in psoriatic arthritis (PsA) patients. Methods: A cross sectional study was performed with a total of 60 patients, PSA patients, 10 healthy individuals and 6 hand osteoarthritis patients (OA). Only PsA patients meeting the CASPAR criteria were included in the study. Results: Spectral Doppler (sD) was used to analyze 208 nail beds. Nail plates on the gray scale (GS) showed loss of the normal three-layered pattern in 89 nails (45.9%). Power Doppler (PD) signal was detected in 189 nail beds (92.2%), showing inflammatory activity in most of the patients and nails assessed. Resistance index (RI) was significantly lower in PsA patients as compared to control groups in both the longitudinal and transverse planes (p<0.001).Nail enthesitis was observed when RI values were below 0.4, characterizing 100% sensitivity and 96% specificity (p<0.01). Conclusions: Nail US scanning presented statistical significance in PsA patients. Future studies could show many inflammatory situations, requiring treatment assessment.