Electroencephalographic mapping and 99mTc HMPAO single-photon emission computed tomography in carbon monoxide poisoning

Abstract

Study objective: To investigate whether topographic analysis of EEG mapping and technetium-99m (99mTc) hexamethylpropylenamine oxide (HMPAO) brain single-photon emission computed tomography (SPECT) can detect cerebral anomalies in the acute phase of carbon monoxide poisoning.

Design: Twelve patients aged 18 to 55 years with severe carbon monoxide poisoning and no history of neurologic disorder were evaluated. Either nasal (5 patients) or hyperbaric (7 patients) oxygen therapy was administered. Criteria for hyperbaric oxygen therapy were blood CO of more than 20%, loss of consciousness, pregnancy, or signs of cardiac injury. After oxygen treatment, all patients had a blood CO value of 0% and no patient had persistent acute signs of toxicity. Patients then were investigated by confentional EEG, EEG mapping, and 99mTc HMPAO brain SPECT. These procedures were performed on the day of admission.

Participants: After nasal (5 patients) or hyperbaric (7 patients) oxygen therapy was administered, 12 adults with severe carbon monoxide poisoning were evaluated. All studies were performed on the day of admission.

Measurements: Conventional EEG, EEG mapping, and 99mTc HMPAO brain SPECT.

Results: While classic EEG was normal in 9 of 12 patients and showed diffuse anomalies in 3, EEG mapping and 99mTc HMPAO brain SPECT demonstrated unilateral or bilateral regional anomalies in 8 of 12 patients. Anomalies were localized in temporo-parieto-occipital areas, the watershed areas of the major cerebral arteries, or in temporal cortex.

Conclusion: These preliminary results suggest that EEG mapping and 99mTc HMPAO brain SPECT can be complementary tools to diagnose early regional cerebral anomalies in carbon monoxide-poisoned patients.