Early changes in apparent diffusion coefficient of rat brain following total circulatory arrest

Abstract

The apparent diffusion coefficient (ADC) of rat brain was determined for the cortex [(771±23)×10−6 μm2/s] and caudate-putamen (CP) [(601±25)×10−6 μm2/s]. Using the ultrafast imaging technique U-FLARE changes in ADC were followed with a 2.4-min temporal resolution after the induction of total circulatory arrest by intravenous KC1 injection. For both tissue types, a biphasic decrease of ADC was observed. The initial fast phase led to an ADC decrease by (27±4)% (cortex) and (29±3)% (CP) within 5 min, whereas the slow continuous decrease of the second phase resulted in (68±3)% (cortex) and (66±3)% (CP) of control after 18 min. The similar relative reduction in ADC for the cortex and the CP meant that an effective distinction between both tissue types persisted after the cessation of systemic and cerebral blood flow.