Effect of field of view variation on CTP assessment of infarct core and penumbra in acute ischemic stroke

The Rapid Processing of Perfusion and Diffusion (RAPID) platform, a validated acute ischemic stroke diagnostic tool, excels in detecting penumbra in large vessel occlusion (LVO) and predicting final infarct volume in recanalized patients. Accurate CT perfusion image quality is essential for assessing infarct core and penumbra volumes. The image spatial resolution is based on the field of view (FOV) in the CT image, while it usually varies depending on the technician's decision. This study examines whether FOV size affects infarct core and penumbra volume measurements in the RAPID system. The study compared arterial input function (AIF), venous output function (VOF) peaks, and time-to-peak (TTP) between large (250 mm) and small (180 mm) FOVs. It also examined the relationship between FOV size and hypoperfusion, infarct core, and mismatch volumes in the RAPID system to assess FOV effects in CTP scans. 62 patients with ischemic infarction were included. The study found no significant differences (p > 0.05) in AIF TTP and VOF TTP between small and large FOVs. However, significant differences were observed in AIF peak (p < 0.001), VOF peak (p < 0.001), hypoperfusion volume (p < 0.001), infarct core volume (p = 0.003), and mismatch volume (p < 0.001) between the two FOV groups. The study concluded that higher spatial resolution CTP images are associated with higher AIF and VOF peaks, a larger hypoperfusion area, a smaller infarct core region, and a larger mismatch volume.