Cerebrovascular Reserve in Patients With Carotid Occlusive Disease Assessed by Stable Xenon-Enhanced CT Cerebral Blood Flow and Transcranial Doppler Export

@article{citeulike:3183048, abstract = {Background and Purpose---- Cerebrovascular reserve (CVR) by both transcranial Doppler ultrasonography (TCD) and quantitative cerebral blood flow (CBF) can identify subgroups of patients at increased risk for stroke. A direct comparison of CVR measurements obtained with both technologies in patients with cerebrovascular occlusive disease is lacking. Methods---- CVRs before and after acetazolamide administration (1 g IV) were measured by TCD insonation of the middle cerebral artery (MCA) and CBF obtained with stable xenon CT (Xe/CT) in 38 patients with carotid occlusive disease. Sensitivity/specificity calculations were based on 2 Xe/CT MCA values: an average over 4 levels and the level with the lowest percent change in CBF. Compromised CVR was defined as no reactivity or a decrease in reactivity. Results---- Using the analysis of the systolic TCD, we found that velocity changes compared with the average Xe/CT MCA CVR showed a sensitivity of 33\%, specificity of 90.6\%, positive predictive value of 54.5\%, and negative predictive value of 80\%. The sensitivity of TCD compared with the lowest Xe/CT CBF CVR was 35.5\%, specificity and positive predictive values were 100\%, and negative predictive value was 66.7\%. The index of validity was between 72\% and 76\%. Conclusions---- TCD is much less sensitive than Xe/CT CBF in identifying patients with compromised CVR. This may be a result of the inability of TCD to identify patients with compromised reserves when their MCA blood flow comes from collateral sources. The lack of correlation between TCD and Xe/CT CBF for identifying patients with compromised CVR should be considered when stroke risk assessments are made by TCD.}, author = {Pindzola, Ronda R. and Balzer, Jeffrey R. and Nemoto, Edwin M. and Goldstein, Steven and Yonas, Howard}, citeulike-article-id = {3183048}, citeulike-linkout-0 = {http://stroke.ahajournals.org/cgi/content/abstract/32/8/1811}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/11486110}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=11486110}, day = {1}, journal = {Stroke}, keywords = {blood, bloodflow, carotid, carotidocclusivedisease, cbf, disease, doppler, occlusive, trancranialdoppler, xenonct}, month = {August}, number = {8}, pages = {1811--1817}, posted-at = {2008-09-05 04:21:19}, priority = {2}, title = {Cerebrovascular Reserve in Patients With Carotid Occlusive Disease Assessed by Stable Xenon-Enhanced CT Cerebral Blood Flow and Transcranial Doppler}, url = {http://stroke.ahajournals.org/cgi/content/abstract/32/8/1811}, volume = {32}, year = {2001} }

TY - JOUR ID - citeulike:3183048 L3 - citeulike-article-id:3183048 N2 - Background and Purpose---- Cerebrovascular reserve (CVR) by both transcranial Doppler ultrasonography (TCD) and quantitative cerebral blood flow (CBF) can identify subgroups of patients at increased risk for stroke. A direct comparison of CVR measurements obtained with both technologies in patients with cerebrovascular occlusive disease is lacking. Methods---- CVRs before and after acetazolamide administration (1 g IV) were measured by TCD insonation of the middle cerebral artery (MCA) and CBF obtained with stable xenon CT (Xe/CT) in 38 patients with carotid occlusive disease. Sensitivity/specificity calculations were based on 2 Xe/CT MCA values: an average over 4 levels and the level with the lowest percent change in CBF. Compromised CVR was defined as no reactivity or a decrease in reactivity. Results---- Using the analysis of the systolic TCD, we found that velocity changes compared with the average Xe/CT MCA CVR showed a sensitivity of 33%, specificity of 90.6%, positive predictive value of 54.5%, and negative predictive value of 80%. The sensitivity of TCD compared with the lowest Xe/CT CBF CVR was 35.5%, specificity and positive predictive values were 100%, and negative predictive value was 66.7%. The index of validity was between 72% and 76%. Conclusions---- TCD is much less sensitive than Xe/CT CBF in identifying patients with compromised CVR. This may be a result of the inability of TCD to identify patients with compromised reserves when their MCA blood flow comes from collateral sources. The lack of correlation between TCD and Xe/CT CBF for identifying patients with compromised CVR should be considered when stroke risk assessments are made by TCD. IS - 8 JF - Stroke EP - 1817 TI - Cerebrovascular Reserve in Patients With Carotid Occlusive Disease Assessed by Stable Xenon-Enhanced CT Cerebral Blood Flow and Transcranial Doppler VL - 32 SP - 1811 KW - blood KW - bloodflow KW - carotid KW - carotidocclusivedisease KW - cbf KW - disease KW - doppler KW - occlusive KW - trancranialdoppler KW - xenonct AU - Pindzola, Ronda AU - Balzer, Jeffrey AU - Nemoto, Edwin AU - Goldstein, Steven AU - Yonas, Howard PY - 2001/08/01/ UR - http://stroke.ahajournals.org/cgi/content/abstract/32/8/1811 ER -