Background Musculoskeletal ultrasound (MSKUS) is capable of visualizing synovitis and bone damage such as erosion. In particular, synovial vascularity as measured by power Doppler (PD) is correlated to rheumatoid arthritis disease activity, and PD signal reveals the prevalence of subclinical synovitis overlooked on physical examination. It is frequently difficult to distinguish bone erosion from normal concave surface of the bone. It is necessary for us to know these normal structures well in evaluating disease activity by using MSKUS. Here we examine the normal feeding vessels and bone surface irregularity in wrist joints.
Objectives To clarify the distribution of feeding vessels in wrist joints and lunate surface irregularity of healthy controls by using MSKUS
Methods The dorsal side of the bilateral wrists was scanned in 2 perpendicular planes with 2D-probe in healthy volunteers. The distribution and bilaterality of feeding vessels in the capsule and the extensor tendon sheath of wrist joint, and the evaluation of bone surface irregularity at lunate were validated.
Results The distribution and bilaterality (Blt) of feeding vessels in healthy volunteers (n=30) were as follows:
Above-trapezoid (Rt:100.0%, Lt:100.0%, Blt:100.0%), intra-extensor digitorum tendon sheath (Rt:86.7%, Lt:66.7%, Blt:43.3%), intra-extensor digiti minimi tendon sheath (Rt:30.0%, Lt:30.0%, Blt:10.0%), above-capitate (Rt:23.3%, Lt:30.0%, Blt:10.0%), above-triangular fibrocartilage complex (Rt:16.7%, Lt:30.0%, Blt:6.7%), distal radial side of the radio-carpal joint (Rt:20.0%, Lt:23.3%, Blt:0.0%), distal end of the ulna (Rt:10.0%, Lt:16.7%, Blt:0.0%), dorsal side of the lunate (Rt:6.7%, Lt:0.0%, Blt:0.0%), palmar side of the extensor digitorum tendon sheath (Rt:0.0%, Lt:3.3%, Blt:0.0%). Feeding vessels from vascular channels were depicted at lunate (Rt:53.3%, Lt:46.7%, Blt:43.3%), the distal side of the radius (Rt:20.0%, Lt:16.7%, Blt:3.3%), triquetrum (Rt:10.0%, Lt:16.7%, Blt:0.0%) and capitate (Rt:6.7%, Lt:10.0%, Blt:0.0%). The frequency of the bone surface irregularity at lunate in healthy volunteers (n=47) and the transverse diameter (TD) (Mean±S.D.) of those were Rt longitudinal plane:57.4% (TD1.26±0.33mm), Rt transverse plane: 51.1% (TD1.20±0.31mm), Lt longitudinal plane: 68.1% (TD1.06±0.28mm), and Lt transverse plane: 42.6% (TD1.29±0.31mm). Bilateral evaluation of those was 53.2%.
Conclusions MSKUS evaluation in wrist joints revealed various normal vessels and bone surface irregularity of lunate. It is necessary to distinguish a normal pattern from a pathological pattern in MSKUS examination.
Disclosure of Interest None declared