Diffusion-Weighted Imaging Study On Ischemic Penumbra Of The Cerebral Infarction

Objective:To explore the ischemic penumbra of the ischemic lesions by using diffusion weighted imaging(DWI) combined with apparent diffusion coefficients (ADC)mapping and T2WI.Methods:MRI was performed in41patients with clinically diagnosed cerebral infarction, DWI were acquired by using echo planar technique.7Hyperacute (less than6hours)15Acute phase (7-24hours),19Early subacute (2-3days).The follow-up MR examinations of all the patients were carried out after clinical treatment. The brain tissue, which showed abnormal high intensity in DWI at first time and appeared normal in T2WI at the reexamination, was regarded as the area of the ischemic penumbra. The brain tissue, which showed abnormal high intensity in DWI at first time and T2WI at the reexamination, was regarded as the infarct area.Measuring and comparing the size of the patients’lesion, When the size of the lesion wasn’t same, to determinate of the apparent diffusion coefficient (ADC) values and the apparent diffusion coefficient ratio (ADCR) in the infarct and ischemic penumbra area.Results:ADC value of the ischemic penumbra only slightly decreased, the ADC values was (6.588±0.717) x10-4mm2/s, and the control area of the ADC values was (8.292±2.046)×10-4mm2/s; ADC values of the infarct area decreased significantly, the ADC values was (3.783±1.032) x10-4mm2/s, and the control area of the ADC values was (7.992±0.828) x10-4mm2/s.IT was a significant correlation that ADCR values of the Lesions in the central area and ischemic penumbra was increased with time.Hyperacute and acute phase ADCR value of the ischemic penumbra is74.394%, value of the infarct area is47.631%, Hyperacute and acute phase ADCR value of the penumbra is higher than the infarct area, the difference between the two has a very significant (P<0.01).Abnormal rate of large cerebral infarction is81.1%, abnormal rate of lacunar infarction is46.6%. Conclusion:The time window of ischemic penumbra may be until24h. and its range of ADC values can be predicted. MRA abnormal detection rate In the acute cerebral infarction, a large area of cerebral infarction was significantly higher than lacunar infarction (<3d).DWI and ADC maps can find in hyperacute and acute phase cerebral infarction and predict of ischemic penumbra, it can give radiological signs for guide patients’thrombolytic and neuroprotective therapy.