Neurosurgery
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Cases of post carotid endarterectomy (CEA) Horner's syndrome have been reported, with symptoms attributed to manipulation of the sympathetic plexus situated along the carotid artery; however, these patients presented with the typical constricted pupil. We report the first 3 cases to our knowledge of mydriasis following CEA. ⋯ We suggest that these cases are secondary to an ischemic phenomenon, specifically to parasympathetic structures such as the ciliary ganglion and/or oculomotor nerve, resulting in autonomic dysfunction manifested by pupillary dilation. A similar finding of mydriasis occurring subsequent to other carotid pathology has been reported, with ischemia to parasympathetic structures also proposed as the underlying etiology. Although pupillary dilation often represents a worrisome neurosurgical sign indicating herniation, it should be recognized that after CEA this finding may be a transient, benign occurrence.
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Biophysical modeling of glioma is gaining more interest for clinical practice. The most popular model describes aggressivity of tumor cells by two parameters: net proliferation rate (ρ) and propensity to migrate (D). The ratio ρ/D, which can be estimated from a single preoperative magnetic resonance imaging (MRI), characterizes tumor invasiveness profile (high ρ/D: nodular; low ρ/D: diffuse). A recent study reported, from a large series of glioblastoma multiforme (GBM) patients, that gross total resection (GTR) would improve survival only in patients with nodular tumors. ⋯ Whatever the degree of tumor invasiveness, as estimated from MRI-driven biophysical modeling, GTR improves survival of GBM patients, compared to PR or BST. This conflicting result should motivate further studies.
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Imaging is paramount to the diagnosis and management of ischemic stroke, offering a battery of structural and functional probes of cerebrovascular physiology. The technical underpinnings of stroke imaging continue to evolve, bringing the neuroscience community increasingly closer to high-resolution, tissue-level biomarkers of brain perfusion, metabolism, and viability. The rapid expansion of neuroimaging in this domain has met with controversies, and in many respects, a lack of generalizable conclusions regarding optimized use in cerebrovascular disease. This review aims to provide the reader with the depth and scope of both established and emerging techniques, and an overview of prevailing viewpoints regarding neuroimaging in acute ischemic stroke.