Prognostication of Recovery in Patients With Acute Ischemic Stroke Through the Use of Brain SPECT With Technetium-99m—Labeled Metronidazole

Abstract

BACKGROUND AND PURPOSE: We hypothesized that technetium-99m-ethylene dicysteine-metronidazole (99mTc-EC-MN) localizes to brain tissue that is hypoxic but viable. This study prospectively evaluated the relationship between neurological outcome and uptake of 99mTc-EC-MN in peri-infarcted regions of the brain. METHODS: Eight patients with acute ischemic stroke in the territory of the left middle cerebral artery underwent 99mTc-EC-MN and 99mTc-ethyl cysteinate dimer (ECD) brain SPECTs on the same day during the subacute stage (10.3+/-2.5 days). The infarct volumes from 99mTc-ECD images (IV(ECD)), infarct volumes from diffusion-weighted MRI images (IV(DW)), and hypoxic volume (HV) from 99mTc-EC-MN images were calculated. The net infarct volume (NIV(ECD)) was defined as IV(ECD) minus HV. The National Institutes of Health Stroke Scale scores were measured on admission and days 1, 3, 7, and 30. RESULTS: IV(ECD) was greater than IV(DW). The lesion-to-normal count-density ratios of 99mTc-EC-MN ranged from 1.80 to 5.96. HV was 60.2+/-65.2 cm3, and the mean percent HV was 24.5+/-28.1% of IV(ECD). NIV(ECD) was 162.6+/-133.4 cm3 and was significantly smaller than IV(ECD). NIV(ECD) was significantly correlated with National Institutes of Health Stroke Scale score at 1 month and was a significant predictor of neurological deficit at 1 month. CONCLUSIONS: 99mTc-EC-MN brain SPECT can detect hypoxic tissue after acute ischemic stroke and, in combination with 99mTc-ECD brain SPECT, is useful in predicting neurological outcome in ischemic stroke patients.