['Existing data on perfusion imaging assumes the perihemorrhagic zone (PHZ) in patients with intracerebral hemorrhage (ICH) to be size steady. This study investigates the size of the perihemorrhagic zone (PHZ) in patients with lobar ICH in relation to hematoma volume during the course of treatment using perfusion CT (PCT).', 'The present analysis is based on a previously reported cohort of 20 patients undergoing surgical evacuation for lobar SICH, with pre- and early postoperative PCT scanning. Time to peak of the residue function (T max) was measured based on the 360° cortical banding method and singular value decomposition. The size of PHZ was determined before and after treatment and correlated with hematoma volume.', 'Preoperative mean hematoma volume constituted 63.0 ml (interquartile ranges (IQR) 39.7-99.4 ml), which correlated significantly (r=0.563, p=0.010) with mean PHZ size (5.67 cm, IQR 5.44-8.17 cm). Following a surgical hematoma evacuation, mean hematoma volume was reduced to 2.5 ml IQR 0.0-9.5 ml, which also resulted in a significant reduction of PHZ size to 0.45 cm(IQR 0.0-1.36 cm; p<0.001). There was no association between postoperative hematoma volume and size of the PHZ.'] Does the extent of the perihemorrhagic perfusion zone correlate with hematoma volume in patients with lobar intracerebral hemorrhage?