POS0127 QUANTITATIVE ASSESSMENT OF FINGER VASCULARITY IN SYSTEMIC SCLEROSIS PATIENTS WITH RAYNAUD’S PHENOMENON USING ULTRASOUND VASCULAR IMAGING

Abstract

BackgroundIn patients with Systemic Sclerosis (SSc), vasculopathy plays an important pathophysiological role and it is almost universally expressed as Raynaud’s Phenomenon (RP). Assessment of vasculopathy/microangiopathy is crucial for early diagnosis of SSc and also is considered in the SSc classification criteria. Currently, this evaluation is performed by nailfold capillaroscopy. However, nailfold capillaroscopy is limited to the nail fold area and is mainly qualitative since is based on the shape, size, and density of the observed capillaries.ObjectivesThe objective of this study is to detect and quantify finger vascularity of SSc patients with RP using four ultrasound vascular imaging techniques. Additionally, the diagnostic performance of quantified finger vascularity was assessed.MethodsThis prospective IRB approved study has enrolled 20 SSc patients fulfilling the 2013 ACR/EULAR classification criteria and presenting RP. Age and sex matched normal volunteers (16 subjects) without RP, were also enrolled. All fingers except thumbs were imaged at room temperature in the seated position. The blood flow of each finger was evaluated on the dorsal (showing nail) and ventral (showing palm) sides using an i24LX8 probe (9-24 MHz) on an Aplio i800 system (Canon Medical Systems, Tustin, CA, USA). Blood flow images were obtained using color Doppler imaging (CDI), power Doppler imaging (PDI), monochrome Superb Microvascular Imaging (mSMI), and color-coded Superb Microvascular Imaging (cSMI) keeping the same imaging settings for all subjects. The percent area of vascularity observed by each technique was quantified offline by counting pixels of blood flow in a 5 x 5 mm square centered at the nail fold for the dorsal side and in a 1 x 1 cm square from the fingertip for the ventral side using Matlab (MathWorks, Natick, MA, USA). The percent vascularity areas from dorsal and ventral sides were averaged over fingers, then t-tests and receiver operating characteristic (ROC) analyses were performed (Youden Index) to assess the ability of the different methods for classifying disease status (RP-SSc from normal controls), allowing to assign diagnostic accuracy.ResultsTwo patients’ data were excluded due to technical errors. The data from 18 RP-SSc patients and 16 normal volunteers were analyzed. The percent vascular areas in patients with RP were significantly lower than those in normal volunteers at both dorsal (p < 0.03) and ventral (p < 0.01). For each imaging technique, the ventral side vascularity showed a higher diagnostic accuracy compared to the dorsal side. Among the four imaging techniques, CDI showed the highest diagnostic accuracy. The mean percent areas by CDI were 6.8 ± 7.1% (mean ± standard deviation) and 15.3 ± 8.9% on the dorsal side (p < 0.01) and 5.3 ± 5.6% and 16.7 ± 7.4% on the ventral side (p < 0.0001) for RP patients and normal volunteers, respectively. The ventral side vascularity by CDI showed the highest diagnostic accuracy of 90% with 88% specificity and 78% sensitivity.ConclusionUltrasonic vascular imaging demonstrated the potential to quantify microangiopathy of RP-SSc. Additionally, the mean percent vascular area averaged across the fingers showed to be accurate (70 to 90%) to differentiate patients with RP-SSc from normal controls, albeit based on small sample size.