Perfusion‐weighted MRI using gadobutrol as a contrast agent in a rat stroke model

Abstract

The purpose of this study was to examine the new nonionic contrast agent gadobutrol in MR perfusion-weighted imaging, including the influence of different concentrations and dosages of the agent on the sensitivity to perfusion alterations. Sixteen rats were examined within 35 to 105 minutes after endovascular occlusion of the middle cerebral artery. A fast T2*-weighted fast low-angle shot (FLASH) sequence was used to acquire four images before and 16 images after bolus injection of .1, .2, .3, and .4 mmol/kg gadobutrol as .5 molar and 1.0 molar formulation. From user-defined regions, we obtained the maximum signal decrease, the relative regional cerebral blood volume, and the bolus delay. Contrast between ischemic and nonischemic regions during bolus passage increased with dose and concentration of the contrast agent. For low doses (.1 and .2 mmol/kg), the ischemic lesion could not or could barely be discerned. For higher doses (.3 and .4 mmol/kg), administration of the 1 molar contrast agent yielded a better contrast between ischemic and nonischemic tissue. Our results suggest that administration of gadobutrol at higher dosage and higher concentration increases sensitivity to perfusion alterations. These results are potentially useful for perfusion-weighted imaging of the human brain, because the volume of contrast agent will be reduced if a solution with higher concentration is used. When using contrast agents in higher concentrations for human examinations, a significant signal decrease may be achieved also with the low doses (.1-.15 mmol/kg).

Value of 1.0-M gadolinium chelates: review of preclinical and clinical data on gadobutrol

“…bolus injected into 16 rats following endovascular occlusion of the middle cerebral artery in escalating doses from 0.1 to 0.4 mmol/kg b.w. In conclusion, increasing doses and concentration of gadobutrol showed a pronounced signal drop in MR perfusion imaging and thus allowed a better discrimination of well-perfused and ischemic brain tissue; however, the effect of increasing dose levels on signal drop was higher compared with the effect of contrast agent concentration [17].…”

Neuroprotective Effect of Delayed Moderate Hypothermia After Focal Cerebral Ischemia

“…22 A side-by-side difference of apparent diffusion coefficient value from homologous pixels (ie, the ischemic and normal hemispheres that best define the ischemic lesion volume in vivo) of 29%, which is highly correlated with postmortem infarct volume, was used to define abnormal ischemic pixels. 22 Relative regional cerebral blood volume (rrCBV) and the relative mean transit time (rMTT) were calculated from the perfusion-weighted MRI data, as described by Heiland et al 23 These parameters were investigated for 5 different regions of interest (ROIs, 1.5-mm diameter) in each hemisphere, including the thalamus, basal ganglia, temporal cortex, sensory cortex, and cingulate gyrus.…”

Monitoring Intravenous Recombinant Tissue Plasminogen Activator Thrombolysis for Acute Ischemic Stroke With Diffusion and Perfusion MRI

“…Perfusion maps were calculated from the concentration time curves as the normalized first moment of the concentration time curve, ie, the time that divides the area under the concentration curve (relative cerebral blood volume) into 2 equal parts (relative MTT or time to midpoint). 16 Quantitative CBF measurement 17 was not performed because of the requirement of extensive postprocessing and thus nonavailability for bedside use. Because quantitative CBF measurements and thus MTT were not available, we chose the unspecific term "perfusion map" instead of MTT map.…”