Delayed cerebral ischemia (DCI) after aneurysmal subarachnoid haemorrhage (aSAH) is a singular pathological entity necessitating early diagnostic approaches and both prophylactic and curative interventions. This retrospective before-after study investigates the effects of a management strategy integrating perfusion computed tomography (CTP), vigilant clinical monitoring and standardized systemic administration of milrinone on the occurrence of delayed cerebral infarction (DCIn). The $${\text{"before"}}$$
"before"
period included 277 patients, and the $${\text{"after"}}$$
"after"
one 453. There was a higher prevalence of Modified Fisher score III/IV and more frequent diagnosis of vasospasm in the $${\text{"after"}}$$
"after"
period. Conversely, the occurrence of DCIn was reduced with the $${\text{"after"}}$$
"after"
management strategy (adjusted OR 0.48, 95% CI [0.26; 0.84]). Notably, delayed ischemic neurologic deficits were less prevalent at the time of vasospasm diagnosis (24 vs 11%, $$p=0.001$$
p
=
0.001
), suggesting that CTP facilitated early detection. In patients diagnosed with vasospasm, intravenous milrinone was more frequently administered (80 vs 54%, $$p<0.001$$
p
<
0.001
) and associated with superior hemodynamics. The present study from a large cohort of aSAH patients suggests, for one part, the interest of CTP in early diagnosis of vasospasm and DCI, and for the other the efficacy of CT perfusion-guided systemic administration of milrinone in both preventing and treating DCIn.