MRI Head Perfusion Given the continued difficulty in identifying patients at risk for and in preventing vasospasm and delayed cerebral ischemia, advanced MRI head perfusion studies are now being performed. MRI head perfusion with decreased intravoxel incoherent motion microvascular perfusion has been associated with vasospasm [38], and elevated blood- brain barrier permeability (Ktrans) was associated with patients who went on to develop delayed cerebral ischemia [39]. Despite these early positive studies, no large or prospective studies have been performed to support the widespread use of MRI head perfusion in the evaluation of suspected vasospasm. MRI Head MRI head offers evaluation of consequences of delayed cerebral ischemia including completed infarction. However, there is no relevant literature to support the use of MRI head in the evaluation of suspected cerebral vasospasm. MRV Head There is no relevant literature to support the use of MRV head in the evaluation of suspected cerebral vasospasm. US Duplex Doppler Carotid Artery There is no relevant literature to support the use of carotid artery US duplex Doppler in the evaluation of suspected cerebral vasospasm. CVD-Aneurysm, Vascular Malformation, and SAH US Duplex Doppler Transcranial TCD is a quick and noninvasive modality to evaluate for increased arterial velocities in the setting of vasospasm. Given the ability to perform the examination at the bedside, daily TCD is frequently used in the screening for vasospasm in at-risk populations. Vasospasm identified on TCD predicts delayed cerebral ischemia with 90% sensitivity, 92% negative predictive value, 71% specificity, and 57% positive predictive value [40]. Although screening for vasospasm with TCD has high sensitivity and negative predictive value, prolonged TCD screening past day 10 post-SAH does not appear to increase detection of delayed cerebral ischemia [41].
Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRI Head Perfusion Given the continued difficulty in identifying patients at risk for and in preventing vasospasm and delayed cerebral ischemia, advanced MRI head perfusion studies are now being performed. MRI head perfusion with decreased intravoxel incoherent motion microvascular perfusion has been associated with vasospasm [38], and elevated blood- brain barrier permeability (Ktrans) was associated with patients who went on to develop delayed cerebral ischemia [39]. Despite these early positive studies, no large or prospective studies have been performed to support the widespread use of MRI head perfusion in the evaluation of suspected vasospasm. MRI Head MRI head offers evaluation of consequences of delayed cerebral ischemia including completed infarction. However, there is no relevant literature to support the use of MRI head in the evaluation of suspected cerebral vasospasm. MRV Head There is no relevant literature to support the use of MRV head in the evaluation of suspected cerebral vasospasm. US Duplex Doppler Carotid Artery There is no relevant literature to support the use of carotid artery US duplex Doppler in the evaluation of suspected cerebral vasospasm. CVD-Aneurysm, Vascular Malformation, and SAH US Duplex Doppler Transcranial TCD is a quick and noninvasive modality to evaluate for increased arterial velocities in the setting of vasospasm. Given the ability to perform the examination at the bedside, daily TCD is frequently used in the screening for vasospasm in at-risk populations. Vasospasm identified on TCD predicts delayed cerebral ischemia with 90% sensitivity, 92% negative predictive value, 71% specificity, and 57% positive predictive value [40]. Although screening for vasospasm with TCD has high sensitivity and negative predictive value, prolonged TCD screening past day 10 post-SAH does not appear to increase detection of delayed cerebral ischemia [41].