AB0927 SUPERB MICROVASCULAR IMAGING COMPARED WITH POWER DOPPLER ULTRASOUND IN ASSESSING SYNOVITIS OF THE KNEE IN JUVENILE IDIOPATHIC ARTHRITIS: A PRELIMINARY STUDY

Abstract

Background Juvenile idiopathic arthritis (JIA) is a complex entity and is the most common rheumatologic disease of the children with the knee being the most frequently affected joint. Extensive proliferation of the synovial cells, synovial thickening and inflammation are the hallmark pathological processes ongoing in the affected joints. The traditional methods in assessing the disease activity involve investigating tenderness, pain, and swelling of the relevant joint on psychical examination in addition to biochemical markers; however, the psychical examination may yield equivocal results in some patients. Sonographic modalities are being increasingly used as a complementary method in the assessment of the joints in JIA and Power Doppler ulltrasound (PDUS) is the current reference sonographic method in assessing the inflammation by measuring the vascularity in the synovium. SMI is a novel Doppler technique using advanced filtering algorithms with an ability to detect even subtle and slow blood flow signals. Objectives: we aimed to investigate the efficiency of Superb Microvascular imaging (SMI) in assessing inflammation of synovium in the knee of patients with JIA compared with PDUS. Methods Both knees of the patients with a diagnosis of clinically active JIA were examined using gray-scale US. The knees with positive US and physical examination findings included in group A while the knees with positive US findings despite negative physical examination findings included in group B. The observers calculated vascularity index (VI) by manually drawing a region of interest (ROI) onto the thickest part of the synovium using PDUS and SMI. Results A total of 41 knees with both clinical and sonographic positive findings constituted group A and 14 knees with sonographic positive findings and normal physical examination categorized as group B in the final cohort. The median SMI-VI (observer 1= 4.9%, IQR 3.6; observer 2= 4.1%, IQR 4.6) was exceeded the median PDUS-VI (observer 1= 1.5%, IQR 1.8; observer 2= 1.5, IQR 1.9) (P 0.05). In all of the patients in group A, SMI was able to identify the presence of vascularity for both observers while no blood flow was detected (VI=0%) using PDUS in 6 patients (14.6%) for observer 1 and 7 patients (17.1%) for observer 2. In all of the patients in group B, SMI was also able to identify the presence of vascularity for both observers while no blood flow was detected (VI=0%) using PDUS in 5 patients (%35.7) for each observers. Conclusion SMI-VI obtained from the hypertrophied synovium of both clinically active and inactive knee joints were substantially higher compared with PDUS-VI in JIA patients. Furthermore, SMI detected the presence of blood flow in patients in whom PDUS could not be able to identify any blood flow. The findings of the present work indicate that SMI seems to a promising tool and a valuable adjunct to conventional US in assessing the inflammation of the synovial tissue in JIA patients.