Etiology of Corpus Callosum Lesions with Restricted Diffusion.

PURPOSE: Infarction of the corpus callosum is rare, and other conditions can cause magnetic resonance imaging (MRI) restricted diffusion in the callosum, leading to diagnostic uncertainty. We sought to characterize the etiology of lesions with diffusion restriction in the corpus callosum. METHODS: Callosal lesions with restricted diffusion were identified at our institution between January 2000 and December 2010. Radiographic and clinical data were reviewed to determine whether the lesion was vascular and if so, to identify the underlying mechanism. RESULTS: A total of 174 cases were reviewed in depth; 47 % were vascular and 53 % were nonvascular. Among vascular cases, atypical mechanisms of stroke (e.g., vasculitis/vasculopathy, hypercoagulable state) were most common (37 %), followed by cardioembolism (28 %). Vascular splenial lesions in particular were likely due to atypical causes of stroke. The most common nonvascular etiologies were trauma (44 %), tumor (22 %), and demyelination (15 %). Vascular lesions were more common in older, non-Caucasian patients with vascular risk factors. Nonvascular lesions were more likely to be found in association with T2-hyperintense cortical lesions, focal intraparenchymal enhancement, or edema/mass effect on MRI. CONCLUSIONS: More than half of lesions with diffusion restriction in the corpus callosum are due to a nonvascular cause. Clinical and radiographic characteristics can help distinguish vascular from nonvascular lesions in the corpus callosum. Nonvascular lesions are more likely to be seen in younger patients without vascular risk factors and are more often accompanied by enhancement and edema. Vascular lesions are most commonly due to atypical stroke etiologies, and these patients may require additional diagnostic testing.

Cervical carotid artery dissection is associated with styloid process length.

OBJECTIVE: To investigate whether cervical carotid artery dissection (CCAD) is associated with anatomic characteristics of the styloid process of the temporal bone. METHODS: CT angiograms from 38 case patients with CCAD and 38 age- and sex-matched control subjects without dissection were studied. Styloid process length, angulation in the axial and rostral-caudal planes, and proximity to the carotid artery were measured bilaterally by raters blinded to radiology reports and clinical information. RESULTS: In control subjects, there was substantial variation in styloid process length (range 4.6-42.9 mm), medial angulation (range 16-89°), caudal angulation (range 31-80°), and proximity to the carotid (range 0.7-15.4 mm). Control subjects also demonstrated marked symmetry between sides (correlation coefficients 0.80 for length, 0.34 for proximity, 0.81 for medial angulation, and 0.87 for caudal angulation). In case patients, the mean styloid length on the side of the dissection was not significantly longer than that on the contralateral side (mean 30.3 vs 29.7 mm, p = 0.30). The styloid process was significantly longer ipsilateral to the dissection in case patients compared with the side-matched process in control subjects (mean 30.3 vs 26.6 mm, p = 0.03). Carotid dissection was associated with increasing styloid process length (OR [OR] 1.08/mm, 95% confidence interval [CI] 1.002-1.17, p = 0.04). The OR of dissection in the highest quartile of length compared with that in the lower 3 quartiles was 4.0 (95% CI 1.3-14.2, p = 0.03). CONCLUSIONS: CCAD is associated with a longer styloid process, suggesting that mechanical injury from the styloid may contribute to the pathogenesis of CCAD.

Blood pressure management in acute stroke.

Blood pressure (BP) is the major determinant of cerebral perfusion yet blood pressure management in acute stroke is complex and controversial. Optimized blood pressure management may improve outcomes in patients with ischemic and hemorrhagic stroke although the available data are conflicting and target BP goals are not well defined. We review the current literature, published guidelines, and emerging research on this important topic. Additionally, the treatment algorithm which we employ is discussed.