Hypoperfusion without ischemia surrounding acute intracerebral hemorrhage

A zone of hypoperfusion surrounding acute intracerebral hemorrhage OCH) has been interpreted as regional ischemia. To determine if ischemia is present in the periclot area, the authors measured cerebral blood flow (CBF), cere bral metabolic rate of oxygen (CMRO2), and oxygen extraction fraction (OEF) with positron emission tomography (PET) in 19 patients 5 to 22 hours after hemorrhage onset. Periclot CBF, CMRO2, and OEF were determined in a 1-cm-w ide area around the do; in the 16 patients without midline shift, periclot data were compared with mirror contralateral regions. All PET images were m asked to exclude noncerebral structures, and all PET measurements were corr ected for partial volume effect due to dot and ventricles. Both periclot CB F and CMRO2 were significantly reduced compared with contralateral values ( CBF: 20.9 +/- 7.6 vs. 37.0 +/- 13.9 ml 100 g(-1) min(-1). P = 0.0004 CMRO2: 1.4 +/- 0.5 vs. 2.9 +/- 0.9 mL 100 g(-1) min(-1), P = 0.00001). Periclot O EF was less than both hemispheric OEF (0.42 +/- 0.15 vs. 0.47 +/- 0.13, P = 0.05; n = 19) and contralateral regional OEF (0.44 +/- 0.16 vs. 0.51 +/- 0 .13, P = 0.05; n = 16). In conclusion, CMRO, was reduced to a greater degre e than CBF in the periclot region in acute ICH, resulting in reduced OEF ra ther than the increased OEF that occurs in ischemia. Thus, the authors foun d no evidence for ischemia in the periclot zone of hypoperfusion in acute T CH patients studied 5 to 22 hours after hemorrhage onset.