FRI0258 A Novel MRI-Based Longitudinal Scoring System for Arterial Involvement in Large-Vessel Vasculitis

Abstract

BackgroundAlthough prevention of arterial progression is a hard therapeutic goal in large-vessel vasculitides (LVV), there is neither an agreed definition of progression nor a proposed method to globally assess arterial injury. This lack of validated clinimetry limits the feasibility of clinical trials. Although distinguishing disease activity from damage in Takayasu arteritis (TA) is difficult, current damage indices lack imaging data. Outside LVV, the only validated quantitative methods to assess arterial damage are NASCET and ECST, both designed for carotid atherosclerosis.ObjectivesStarting from NASCET and ECST, we sought to develop an objective widely applicable magnetic resonance (MR)-based system for scoring large artery injury in TA and large vessel-giant cell arteritis (LV-GCA).MethodsNASCET was selected as a starting point as it only requires intraluminal data which are: i) more widely accessible in routine clinical practice, ii) require less acquisition time than arterial wall sequences, iii) more directly describe the haemodynamic derangement in LVVs, where wall thickening may occur in the absence of demonstrable luminal changes. NASCET was modified to account for the intrinsic characteristics of LVV by: i) defining a core set of arteries to be evaluated, with the final score determined by summing individual artery scores, ii) measuring the reference diameter for every artery in a plane judged “uninvolved”; iii) including the length of the stenotic segment in the algorithm, iv) scoring aneurysmal disease similarly to stenotic disease, based on the percent diameter dilatation and length of the involved segment (Fig. 1A). A cohort of 60 patients with TA or LV-GCA was selected, and those with vascular progression or improvement identified based on the radiologist's judgement. Cross-sectional and longitudinal analysis by two independent observers was performed. The K-inter-observer variability and the sensitivity of the score in distinguishing patients with stable or progressive vascular involvement was evaluated.ResultsAlthough more time-consuming than conventional assessment, our initial impression is that this new index is more precise. To date, we have evaluated 41 scans from 21 patients and scoring of the remaining images will be concluded in 3 months. Arterial involvement was classified as type IIa, IIb, III and V in 2, 1, 1 and 17 patients respectively. The median vascular score of the 21 pts was 16 (range 7-48). Analysis of Type V disease identified pts with both minimal and extensive arterial artery injury (median 24, range 9-42), demonstrating the precision of the index. 12 scans were judged to be stable, 6 improved and 2 worsened. This correlated with changes in the arterial score (median from baseline scan of -1.5 (range -5 to -1) for improved scans, of 0 (range 0 to 1) for stable scans and 7.5 (range 1 to 14) for worsening scans (p<0.001 stable versus improved, and 0.022 stable versus progression, Fig. 1B).ConclusionsWe are evaluating a new index for objectively quantifying arterial injury in ...

Takayasu arteritis: advanced understanding is leading to new horizons

“…Turning to those with active disease at presentation, Kerr followed 34/60 patients angiographically, and 88% exhibited disease progression [29]. Our recent prospective longitudinal MR angiography study of unselected patients receiving treatment revealed that 40% of vasculitic lesions remained stable, 37% progressed and 23% improved (median 18 months) [33]. A recent study reported 10-year event-free survival, relapse-free survival and complication-free survival rates approaching 48, 70 and 54% respectively [31].…”

“…This approach requires a much shorter MRI acquisition time than detailed assessment of changes in the arterial wall. Furthermore, we have shown that monitoring in this way with MRI allows accurate assessment of disease extent and phenotype and long-term monitoring of disease evolution [33].…”

“…Furthermore, standardized methods for quantifying imaging data also remain to be developed. We and others are investigating novel approaches for image analysis [33,81,134]. Similarly, the OMERACT working group is working towards development of a core set of outcomes for LVV, incorporating imaging data [93,98].…”