The use of MRI apparent diffusion coefficient (ADC) in monitoring the development of brain infarction

117 work-ups in 98 patients with cerebral infarction (12 hyperacute, 43 acute, 29 subacute, 10 steady, and 23 chronic infarctions) were imaged with both conventional MRI and diffusion weighted imaging. The average ADC values, the relative ADC (rADC) values, and the ADC values or rADC values from the center to the periphery of the lesion were calculated.The average ADC values and the rADC values of hyperacute and acute infarction lesion depressed obviously. rADC values in hyperacute and acute stage was minimized, and increased progressively as time passed and appeared as "pseudonormal" values in approximately 8 to 14 days. Thereafter, rADC values became greater than normal in chronic stage. There was positive correlation between rADC values and time (P < 0.01). The ADC values and the rADC values in hyperacute and acute lesions had gradient signs that these lesions increased from the center to the periphery. The ADC values and the rADC values in subacute lesions had adverse gradient signs that these lesions decreased from the center to the periphery.The ADC values of infarction lesions have evolution rules with time and space. The evolution rules with time and those in space can be helpful to decide the clinical stage, and to provide the evidence in guiding the treatment or judging the prognosis in infarction.Brain infarction leads to high mortality and disability [1]. The post-infarction treatments available were largely dependent on the timing after infarction to determine the stages of brain damage [2]. The fast and accurate radiological diagnosis could provide important reference in judging the timing and development stages of brain infarction. In recent years, the diffusion weighted imaging (DWI) based on echo planar imaging (EPI) has emerged to be applicable in early diagnosis of brain infarction [3-9]. The present study investigated the changes of apparent diffusion coefficient (ADC) and relative ADC (rADC) values in different timing points after brain infarcti