LAUSR

BACKGROUND We hypothesized immediate postprocedural image features were associated with early regression of flow-diverted aneurysm. We had compared imaging features from digital subtraction angiography and spin echo T2-weighted MRI between early total regression and partial regression groups. METHODS Thirty consecutive patients with large and giant aneurysms were treated with pipeline embolization devices and divided into two groups according to follow up angiographic result after three to six months; total or near total regression (n=20) and partial regression of aneurysmal sac (n=10). The baseline characteristics, percent area of stagnated iodine contrast agent on anterior-to-posterior and lateral view of angiography just after installation of pipeline device, and median, minimal, and 10-percentile signal intensity of aneurysmal sac on T2-weighted spin echo image after one day of procedure were compared between two groups. RESULTS Demographic data comparison between two groups showed no significant difference. Volume of treated aneurysmal sac was not different (2559.28 mm3±3021.45, 2551.76 mm3±6550.58, p=0.455). Total or near total regression group showed larger area of percent iodine stagnation on lateral view of angiography than partial regression group (52.26%, 23.35%, p=0.002). Median, minimal and 10-percentile signal intensity of VOI were higher in total or near total regression group than partial regression group (1.29 vs 0.93, p=0.025; 0.07 vs 0.00, p=0.042; 0.57 vs 0.24, p=0.005). CONCLUSSION Percentage area of contrast media stagnation on lateral angiography, and median, minimal and 10-percentile signal intensity of VOI of treated aneurysmal sac on T2 weighted image can be used to predict early regression of aneurysmal sac.