Background/Purpose: To assess the intra-operator and inter-operator reliability of two-dimensional (2D) and three-dimensional (3D)-power Doppler ultrasonography (PDUS) computer-aided quantification data for wrist joint vascularity.

Methods: This is a single-center, cross-sectional outpatient study using convenience sampling. Patients fitting the1987 ACR classification criteria for rheumatoid arthritis having at least one painful swollen wrist at the rheumatology clinic of Taichung Veterans General Hospital regardless of their DAS28 scores were enrolled. 2D- and 3D-PDUS examinations of swollen wrist joints were performed using a high-resolution, real-time ultrasound equipment (Phillips iU22 intelligent 3D ultrasound system, USA) with two transducers sequentially. One is a 5-13 MHz broadband linear array transducer (volumetric transducer) that is able to do a 2D scan and an automatic volume scan. The other is a “hockey stick”, 7-15 MHz broadband linear transducer. The participants underwent three consecutive 2D PDUS assessment using the “hockey stick” linear transducer and the volumetric transducer, and three consecutive 3D PDUS assessment using the volumetric transducer in a dark room at room temperature (25ßC) within 30 minutes of clinical evaluation by two sonographers (HH Chen and KL Lai). The vascular software, QLAB, provided by the Philips performed quantification analyses, including the area/volume, vascularization index (VI), flow index (FI) and vascularization flow index (VFI) for 2D- and 3D-PDUS respectively. Inter-operator and intra-operator reliability of computer-aided quantification are assessed by calculating intra-class correlation coefficients (ICCs).

Results: A total of 60 wrists in 48 RA patients were evaluated. The intra-operator ICCs of area, VI, FI, and VFI for 2D PDUS were 0.966, 0.952, 0.933 and 0.947 assessed by the “hockey stick” linear transducer, and were 0.972, 0.979, 0.814 and 0.979 assessed by the volumetric probe. The intra-operator ICCs of volume, VI, FI, and VFI for 3D-PDUS were 0.939, 0.965, 0.871, and 0.964. The inter-operator ICCs of area, VI, FI, and VFI for 2D-PDUS were 0.971, 0.968, 0.884, and 0.962 assessed by the “hockey stick” linear transducer, and were 0.977, 0.974, 0.837, and 0.973 assessed by the volumetric transducer. The inter-operator ICCs of volume, VI, FI, and VFI for 3D-PDUS were 0.388, 0.983, 0.874, and 0.983. The mean ± SD 2D VFI obtained by the “hockey stick” linear transducer was significantly higher than that obtained by the volumetric transducer (12.58 ± 8.57 vs. 10.66 ± 8.11, p = 0.008).

Conclusion: The present study demonstrates good intra-operator and inter-operator reliabilities of both 2D- and 3D-PDUS computer-aided quantification data for wrist joint vascularity in patients with RA. The 7-15 MHz “hockey stick” linear transducer detects greater Doppler signals than the 5-13 MHz volumetric transducer.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/assessment-of-wrist-joint-inflammation-in-patients-with-rheumatoid-arthritis-by-quantitative-two-and-three-dimensional-power-doppler-ultrasonography/