Prediction of occluded-side M1 vessel diameter using pre-procedural magnetic resonance angiography

To determine whether the occluded-side M1 vessel diameter on post-procedural digital subtraction angiography (DSA) can be predicted from that on pre-procedural magnetic resonance angiography (MRA) and its usefulness for aspiration catheter selection.

We retrospectively analyzed 41 cases of M1 occlusion undergoing mechanical thrombectomy with successful recanalization and pre- and post-procedural MRA at our institution between January 2020 and December 2024. The relationship between the catheter-to-vessel ratio (CVR), calculated from aspiration catheter's outer diameter and occluded-side M1 vessel diameter on pre-procedural MRA, and first-pass effect was assessed.

The mean occluded-side M1 vessel diameter was 2.2 ± 0.3 mm on pre-procedural MRA and 2.4 ± 0.4 mm on post-procedural DSA; the latter showed a strong correlation with the former (r = 0.925, p < 0.001), and the regression equation was as follows: occluded-side M1 vessel diameter on post-procedural DSA (mm) = 0.19 + 1.025 × occluded-side M1 vessel diameter on pre-procedural MRA (mm) (R² = 0.856). The occluded-side M1 vessel diameter on post-procedural DSA approximated from the mean occluded-side M1 vessel diameter on pre-procedural MRA was pre-procedural MRA measurement + 0.2 mm. First-pass effect was achieved in 66.7 % of cases with CVR ≥ 0.80 and in 25.0 % of cases with CVR < 0.80 (p = 0.049).

When treating M1 occlusion, adding 0.2 mm to the occluded-side M1 vessel diameter on pre-procedural MRA measurement allows prediction of the actual M1 vessel diameter. Selecting an aspiration catheter with CVR ≥ 0.80 may help achieve first-pass effect.