AUTHOR=Kaesemann Philipp , Thomalla Götz , Cheng Bastian , Treszl Andras , Fiehler Jens , Forkert Nils Daniel 

TITLE=Impact of Severe Extracranial ICA Stenosis on MRI Perfusion and Diffusion Parameters in Acute Ischemic Stroke

JOURNAL=Frontiers in Neurology

VOLUME=5

YEAR=2014

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2014.00254

DOI=10.3389/fneur.2014.00254

ISSN=1664-2295

ABSTRACT=<p><bold>Purpose:</bold> The aim of this study was to investigate the impact of a coexisting internal carotid artery (ICA) stenosis on lesion volumes as well as diffusion and perfusion parameters in acute ischemic stroke resulting from middle cerebral artery (MCA) occlusion.</p><p><bold>Material and methods:</bold> Magnetic resonance imaging data of 32 patients with MCA occlusion with or without additional ICA stenosis imaged within 4.5 h of symptom onset were analyzed. Both groups consisted of 16 patients. Acute diffusion lesions were semi-automatically segmented in apparent diffusion coefficient (ADC) MRI datasets. Perfusion maps of cerebral blood volume (CBV), cerebral blood flow, mean transit time and <italic>T</italic><sub>max</sub> were calculated using perfusion-weighted MRI datasets. Tissue-at-risk (TAR) volumes were generated by subtracting the ADC lesion from the hypoperfusion lesion defined by <italic>T</italic><sub>max</sub> &gt;6 s. Median ADC and perfusion parameter values were extracted separately for the diffusion lesion and TAR and used for statistical analysis.</p><p><bold>Results:</bold> No significant differences were found between the groups regarding the diffusion lesion and TAR volumes. Statistical analysis of diffusion and perfusion parameters revealed CBV as the only parameter with a significant difference (<italic>p</italic> = 0.009) contributing a small effect (η<sup>2</sup> = 0.11) to the group comparison with higher CBV values for the patient group with a coexisting ICA stenosis, while no significant effects were found for the other diffusion and perfusion parameters analyzed.</p><p><bold>Conclusion:</bold> The results of this study suggest that a coexisting ICA stenosis does not have a strong effect on tissue status or perfusion parameters in acute stroke patients except for a moderate elevation of CBV. This may reflect improved collateral circulation or ischemic preconditioning in patients with a pre-existing proximal stenosis balancing impaired perfusion from the stenosis.</p>