COMPARISON OF THREE-DIMENSIONAL POWER DOPPLER ULTRASONOGRAPHY OF SYNOVIAL VASCULARITY WITH CONTRAST ENHANCED MAGNETIC RESONANCE IMAGING IN PATIENTS WITH RHEUMATOID ARTHRITIS

Purpose: The recent introduction of potent joint-protective therapies for the management of patients with rheumatoid arthritis (RA) created new demands for the sensitivity and precision of predicting and monitoring synovitis and erosive damage. Since vasodilation and alteration of the synovial microvasculature (angiogenesis) are early events in RA indicating inflammatory activity, imaging techniques such as contrast enhanced magnetic resonance imaging (MRI) and power Doppler ultrasonography (PDUS) including three-dimensional (3D) imaging are promising tools to assess and monitor arthritic activity [1,2].

We compared 3D PDUS with contrast enhanced MRI of the wrist of RA patients to evaluate the reliability of 3D PDUS for the assessment of synovial hypervascularity associated with inflammatory activity.

Methods and Materials: 10 Patients with clinical active arthritis of the wrist determined by tenderness and soft-tissue swelling were examined by contrast enhanced MRI, 2D and 3D PDUS. Ultrasound investigation was performed with a HDI 5000 (ATL / Phillips) unit by means of a 5–12MHz linear array transducer. In a region with high Doppler signal intensity the transducer was moved in one direction (free-hand technique) to obtain a sequence of 2D power Doppler images to provide the third dimension. The online 3D power Doppler function provided by the ATL / HDI 5000 vascular software was used to generate a three-dimensional image of the peri- and intraarticular blood vessels in which grey-scale information of the surrounding tissue had been already subtracted. MRI examinations were performed usig a 1,5 T Scanner (Magnetom Sonata, Siemens Medical Solutions, Erlangen Germany). In MRI, time resolved coronal contrast enhanced T1-weighted sequences with fat suppression were acquired during a 7 minutes period to assess tissue enhancement. Maximum slope, relative enhancement and time to peak for synovial enhancement were calculated and compared to 2D and 3D PDUS imaging.

Results: In all 10 patients with clinical active arthritis by 2D PDUS, an increased microvascular Doppler flow could be found, and by 3D PDUS a blood vessel tree branching out from periarticular small blood vessels into the joint capsule could be visualized. Comparison of 3D PDUS findings with relative enhancement and maximum slope of contrast enhancement in MRI showed a strong correlation in all 10 patients.

Conclusions: When compared with clinical symptoms, 3D PDUS is a reliable imaging technique for assessing synovial vascularitiy in inflamed wrists of RA patients. It provides similar results as the gold standard dynamic MRI.

References

[1] Strunk J, Lange U. Three-dimensional power Doppler sonographic visualization of synovial angiogenesis in rheumatoid arthritis. J Rheumatol 2004; 31(5):1004–1006

[2] Strunk J, Heinemann E, Neeck G, Schmidt KL, Lange U. A new approach to studying angiogenesis in rheumatoid arthritis by means of power Doppler ultrasonography and measurement of serum vascular endothelial growth factor. Rheumatology 2004; 43:1480–83