Background To compare the evolution of the infarct lesion volume on both diffusion-weighted imaging and fluid-attenuated inversion recovery in the first five days after endovascular thrombectomy. Methods We included 109 patients from the CRISP and DEFUSE 2 studies. Stroke lesion volumes obtained on diffusion-weighted imaging and fluid-attenuated inversion recovery images both early post-procedure (median 18 h after symptom onset) and day 5, were compared using median, interquartile range, and correlation plots. Patients were dichotomized based on the time after symptom onset of their post procedure images (≥18 h vs. <18 h), and the degree of reperfusion (on Tmax>6 s; ≥ 90% vs. < 90%). Results Early post-procedure, median infarct lesion volume was 19 ml [(IQR) 7-43] on fluid-attenuated inversion recovery, and 23 ml [11-64] on diffusion-weighted imaging. On day 5, median infarct lesion volume was 52 ml [20-118] on fluid-attenuated inversion recovery, and 37 ml [16-91] on diffusion-weighted imaging. Infarct lesion volume on early post-procedure diffusion-weighted imaging, compared to fluid-attenuated inversion recovery, correlated better with day 5 diffusion-weighted imaging and fluid-attenuated inversion recovery lesions (r = 0.88 and 0.88 vs. 0.78 and 0.77; p < 0.0001). Median lesion growth was significantly smaller on diffusion-weighted imaging when the early post-procedure scan was obtained ≥18 h post stroke onset (5 ml [-1-13]), compared to <18 h (13 ml [2-47]; p = 0.03), but was not significantly different on fluid-attenuated inversion recovery (≥18 h: 26 ml [12-57]; <18 h: 21 ml [5-57]; p = 0.65). In the <90% reperfused group, the median infarct growth was significantly larger for diffusion-weighted imaging and fluid-attenuated inversion recovery (diffusion-weighted imaging: 23 ml [8-57], fluid-attenuated inversion recovery: 41 ml [13-104]) compared to ≥90% (diffusion-weighted imaging: 6 ml [2-24]; p = 0.003, fluid-attenuated inversion recovery: 19 ml [8-46]; p = 0.001). Conclusions Early post-procedure lesion volume on diffusion-weighted imaging is a better estimate of day 5 infarct volume than fluid-attenuated inversion recovery. However, both early post-procedure diffusion-weighted imaging and fluid-attenuated inversion recovery underestimate day 5 diffusion-weighted imaging and fluid-attenuated inversion recovery lesion volumes, especially in patients who do not reperfuse.
Keywords: Brain; MRI; ischaemic stroke; lesions; radiology; stroke.