Regional cerebral blood flow in patients with carbon monoxide intoxication

Early detection of regional cerebral anomalies in acute carbon monoxide (CO) poisoning by (99m)Tc-hexamethylprophylene amine oxime (HMPAO) brain single photon emission computed tomography (SPECT) imaging has been reported previously. However, SPECT findings varied in these studies because of their small population sizes. In this study, we included 96 patients with acute CO intoxication and analyzed the regional perfusion changes in these patients by means of HMPAO brain SPECT.

Ninety-six patients, aged 4-80 years (mean age 32 years) with acute CO intoxication diagnosed by our emergency department were included in this study. Exclusion criteria included previous cerebrovascular diseases, brain injury, brain surgery and any known neurological and psychological disorders. All patients underwent a brain scan using a dual-head camera and fan-beam collimator 90-120 min after injection of (99m)Tc-HMPAO. Brain SPECT images were obtained for interpretation.

Our data suggested that 79 of the 96 patients (82.3 %) had abnormal HMPAO brain images. The predominant site of disease was basal ganglia (52/96 = 54.2 %), followed by temporal lobe (48/96 = 50.0 %), parietal lobe (44/96 = 45.8 %), frontal lobe (30/96 = 31.2 %), occipital lobe (21/96 = 21.9 %) and thalamus (8/96 = 8.3 %). No patients with acute CO intoxication had perfusion abnormalities in the cerebellum. In addition, there was no significant difference in serum COHb levels between patients with abnormal and normal HMPAO brain images.

(99m)Tc-HMPAO SPECT imaging is a useful tool to detect functional brain injury in acute CO intoxication.