Taussky, Philipp

Object Near-infrared spectroscopy (NIRS) offers noninvasive bedside measurement of direct regional cerebral arteriovenous (mixed) brain oxygenation. To validate the accuracy of this monitoring technique, the authors analyzed the statistical correlation of NIRS and CT perfusion with respect to regional cerebral blood flow (CBF) measurements. Methods The authors retrospectively reviewed all cases in which NIRS measurements were obtained at a single, academic neurointensive care unit from February 2008 to June 2011 in which CT perfusion was performed at the same time as NIRS data was collected. Regions of interest were obtained 2.5 cm below the NIRS bifrontal scalp probe on CT perfusion with an average volume between 2 and 4 ml, with mean CBF values used for purposes of analysis. Linear regression analysis was performed for NIRS and CBF values. Results The study included 8 patients (2 men, 6 women), 6 of whom suffered subarachnoid hemorrhage, 1 ischemic stroke, and 1 intracerebral hemorrhage and brain edema. Mean CBF measured by CT perfusion was 61 ml/100 g/min for the left side and 60 ml/100 g/min for the right side, while mean NIRS values were 75 on the right and 74 on the left. Linear regression analysis demonstrated a statistically significant probability value (p < 0.0001) comparing NIRS frontal oximetry and CT perfusion–obtained CBF values. Conclusions The authors demonstrated a linear correlation for frontal NIRS cerebral oxygenation measurements compared with regional CBF on CT perfusion imaging. Thus, frontal NIRS cerebral oxygenation measurement may serve as a useful, noninvasive, bedside intensive care unit monitoring tool to assess brain oxygenation in a direct manner.

Incidental findings pose considerable management dilemmas for the treating physician and psychological burden for the respective patient. With an aging population, more patients will be diagnosed with asymptomatic internal carotid artery stenosis. Patients will have to be counseled with regard to treatment options according to their individual risk profile and according to professionals' knowledge of evidence-based data derived from large randomized control trials. Treatment consensus has long been lacking for patients with asymptomatic carotid artery stenosis prior to any randomized controlled trials. Additionally, an individual's risk profile may be hard to assess according to knowledge gained from randomized controlled trials. Moreover, while earlier studies compared carotid endarterectomy and medical therapy, in the past years, a new therapeutic modality, carotid artery angioplasty and stenting, has emerged as a possible alternative. This has been evaluated in a recent randomized controlled trial, the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST), which compared carotid endarterectomy with angioplasty and stenting in both symptomatic and asymptomatic patients. The following review summarizes current knowledge of the natural history, diagnosis, and treatment strategies to counsel patients with asymptomatic carotid artery stenosis.