Fig. 2.

Microscope Integrated OCT. A Light microscopic image after right fronto-lateral craniotomy, during dissection of dura mater. Opened segment shows Sylvian fissure with superficial Sylvian veins and temporal as well as frontal brain cortex. Orange line indicates region of scan. B OCT scan of dura mater depicting the (1) outer endosteal and (2) inner meningeal layer. Strikingly, a (3) subdural space is present, enabling a clear definition of (2) the inner meningeal dural layer and the (4) arachnoid barrier cell membrane. Furthermore, (5) subarachnoid blood vessels, (6) subarachnoid space, (7) trabecular system, (8) brain cortex, and (9) reflection artifacts are depicted by the transdural OCT scan. Red line indicates the area of enlarged excerpt. C Enlarged excerpt demonstrating details of transdural OCT scan. D Schematic drawing of microstructures: (1) + (2) dura mater, (1) outer endosteal layer, (2) inner meningeal layer, (3) subdural space, (4) subarachnoid space (4) arachnoid barrier cell membrane, (5) subarachnoid blood vessels, (6) subarachnoid space, (7) trabecular system, (8) brain cortex, and (9) reflection artifacts; see Hartmann et al. [16], figure edited with permission from the authors. E OCT scan of frontal lobe at frontal operculum visualizing the collapsed SAS after CSF release, with adjacent internal blood vessels. Red rectangle shows enlarged details of the OCT-Scan; see Hartmann et al. [17, 18], figure edited with permission from the authors. F Light microscopic intraoperative image of parent vessel: right internal carotid artery. Orange horizontal line indicates area of OCT scan. G OCT scan of parent vessel. (1 Tunica externa; (2) tunica media; (3) tunica interna; (4) atherosclerotic plaque; (5) vasa vasorum. H Light microscopic intraoperative image of ramus communicans aneurysm seen from a left fronto-lateral approach. I OCT scan of the neck of the ramus communicans anterior aneurysm (CA) demonstrating the continuous fading transition from a 3-layered configuration of the parent vessel to the mono-layered appearance of the CA dome. (1) CA dome; (2) CA neck; (3) parent vessel. J Light microscopic intraoperative image of right proximal internal carotid artery aneurysm seen from a right fronto-lateral approach; orange lines indicate the area of OCT scan at the aneurysm dome with artherosclerotic plaque. K Longitudinal OCT scan at aneurysm dome demonstrating intra-aneurysmatic atherosclerotic plaque; see Hartmann et al. [17, 18], figures edited with permission from the authors