Assessment of Ischemic Volumes by Using Relative Filling Time Delay on CTP Source Image in Patients with Acute Stroke with Anterior Circulation Large Vessel Occlusions

Case 1. A 46-year-old man with acute occlusion of the right MCA. CTP source imaging (SI) from a 256-section CT scanner showed that the first detection of contrast in the affected right hemisphere (red arrowhead) was delayed by 1 cycle (4 seconds for 1 cycle) after the first detection of contrast in the left Sylvian fissure (red arrow). The relative filling time delay (rFTD) was 4 seconds, which corresponds to a grade of 1 (A). Mismatch imaging calculated by software demonstrated a target mismatch between hypoperfusion volume (67 mL) and core volume (14 mL) (B). Case 2. A 24-year-old man with acute occlusion of the left MCA. CTP-SI from a 64-section CT scanner showed that the first detection of contrast in the affected left hemisphere (red arrowhead) was delayed by 5 cycles (1.3 seconds for 1 cycle) after the first detection of contrast in the right Sylvian fissure (red arrow). The rFTD was 6.5 seconds, which corresponded to a grade of 2 (C). Mismatch imaging showed a large core volume of 98 mL and no TMM (D).