Prediction of subacute infarct lesion volumes by processing apparent diffusion coefficient maps based on apparent diffusion coefficient cut-off values in patients with acute stroke / 中华放射学杂志

ABSTRACT

Objective To explore the feasibility of prediction of subacute infarct lesion volumes by processing ADC maps based on ADC cut-off values in patients with acute stroke.Methods MRI was performed in 20 patients with clinically diagnosed acute infarct less than 6 h after stroke onset.The MRI included a DWI and conventional MRI.The follow-up MR examinations of all the patients were carried out within 4-7 days after admission.The brain tissue, which showed abnormal high intensity both in DWI at the baseline and FLAIR at the reexamination , was regarded as the area of the initial ischemia core.Graphic-penumbra was regarded as the difference between initial DWI and follow-up FLAIR.The ADC values of the ischemia core, graphic-penumbra and the contralateral normal brain tissue , the relative ADC (rADC) were measured.The rADC value of the graphic-penumbra was defined as the ADC cut-off values.GE medical system based on ADC cut-off values was also tested in these patients to obtain ADC maps.The lesion volumes, the abnormal area seen on the DWI , ADC maps and follow-up FLAIR, were also measured.rADC values in different areas were analyzed by paired Student t test.Relationship between baseline DWI , ADC map and follow-up FLAIR was analyzed using Spearman rank-order correlation test , and Kruskal-Wallis H test was used to compare the volumes among three groups.Results Absolute ADC and rADC values gradually increased from the core to the periphery of the ischemic lesion.The absolute ADC values statistically differed from those on the contralateral side for both ischemia core and graphic-penumbra.The rADC values were significantly decreased in the ischemia core ( 0.620 ±0.116 ) compared with the graphic-penumbra values (0.809 ±0.097;t =8.083,P 0.05).Conclusions Data shows the high feasibility of prediction of subacute infarct lesion volumes by processing ADC maps based on ADC cut-off values in patients with acute stroke , without intravenous contrast material, and it provides a new method for outcome prediction.