To investigate highly temporally resolved MR-angiography (MRA) with time-resolved imaging with stochastic trajectories (TWIST) of the hand as supplementary tool for dynamic assessment of synovitis and vascular pathologies in rheumatoid diseases.
A coronal dynamic TWIST-MRA-sequence (0.7 mm × 0.7 mm × 1.4 mm, temporal resolution 2.5s, time of acquisition 4 min) of the predominantly affected hand of 17 patients with suspected rheumatoid disease was acquired after contrast administration (Multihance, Bracco Imaging SpA) at 3T (Magnetom VERIO, 8-channel-knee-coil, Siemens Healthcare). As standard of reference, contrast enhanced non fat-saturated coronal and fat-saturated axial T1-w sequences were acquired. These static sequences and the dynamic TWIST-MRA-maximum-intensity-projections (MIP) were separately assessed by two readers in consensus, recording the number of synovial lesions (wrist, intercarpal, metacarpophaleangal/proximal/distal interphalangeal joints), signs of tenosynovitis and vasculitis. Diagnostic confidence was rated (4-point-scale: 4=excellent; 1=non-diagnostic). Statistical significance was tested using the Wilcoxon-rank-sum-test.
An insignificantly lower number of synovial lesions (n=72 vs. 89; p=0.1) and only 3/9 cases with tenosynovitis were identified by the TWIST-MRA. For detected lesions, diagnostic confidence was comparable (MRA: 3.64; static T1-w post contrast: 3.47). In patients with high clinical activity dynamic MRA showed very early synovial enhancement. Only dynamic MRA detected 3 cases of vasculitis (subsequently confirmed with digital-subtraction-angiography).
TWIST-MRA facilitates fast detection of synovitis. Although dynamic MRA of the hand is inferior to static contrast enhanced sequences in assessing the number of synovitic and tenosynovitic lesions, its high temporal resolution allows for fast visual grading of disease activity and assessment of vasculitis without additional contrast material application.