Pressure maps of Case #6 and #7. Both cases were around 80% stenoses of MCA-M1 but with different lengths (double-headed arrows) and proximal vessel diameters. Hemodynamic severities of the two cases differed in terms of PR and PG. The PRs were −1.30 and −75.70, respectively. And PGs were 300 and 5,382 mmHg/cm, respectively. MCA-M1 indicates M1 segment of middle cerebral artery; PR, pressure ratio; PG, pressure gradient.