Collateral Clock Is More Important Than Time Clock for Tissue Fate.

Background and Purpose- Although perfusion abnormality is an increasingly important therapeutic target, the natural history of tissue at risk without reperfusion treatment is understudied. Our objective was to determine how time affects penumbral salvage and infarct growth in untreated acute ischemic stroke patients and whether collateral status affects this relationship. Methods- We used a prospectively collected, multicenter acute stroke registry to assess acute stroke patients who were not treated with intravenous thrombolysis or endovascular treatment. We analyzed baseline computed tomography angiogram and computed tomography perfusion within 24 hours of stroke onset along with follow-up imaging and assessed time from stroke onset to baseline imaging, ASPECTS (Alberta Stroke Program Early CT Score), vessel occlusion, collaterals, ischemic core, and penumbra. Penumbral salvage and infarct growth were calculated. Correlations between time and penumbral salvage and infarct growth were evaluated with Spearman correlation. Penumbral salvage and infarct growth were compared between subjects with good versus poor collateral status using the Wilcoxon rank-sum test. Clinical and imaging factors affecting penumbral salvage and infarct growth were evaluated by linear regression. Results- Among 94 untreated stroke patients eligible for this analysis, the mean age was 65 years, median National Institutes of Health Stroke Scale score was 13, and median (range) time from stroke onset to baseline imaging was 2.9 (0.4-23) hours. There was no correlation between time and salvaged penumbra ( r=0.06; P=0.56) or infarct growth ( r=-0.05; P=0.61). Infarct growth was higher among those with poor collaterals versus those with good collaterals (median, 52.3 versus 0.9 cm3; P<0.01). Penumbral salvage was lower among those with poor collaterals compared with those with good collaterals (poor, 0 [0-0]; good, 5.9 cm3 [0-29.4]; P<0.01). Multivariable linear regression demonstrated that collaterals, but not time, were significantly associated with infarct growth and penumbral salvage. Conclusions- In this natural history study, penumbral salvage and infarct growth were less time dependent and more a measure of collateral flow.

Imaging of Cerebrospinal Fluid Rhinorrhea and Otorrhea.

As the obesity epidemic grows in the United States, rhinorrhea and otorrhea from spontaneous cerebrospinal fluid (CSF) leaks secondary to untreated idiopathic intracranial hypertension are increasing in prevalence. CSF rhinorrhea and otorrhea should also be carefully evaluated in posttraumatic and postsurgical settings, because untreated CSF leaks often have serious consequences. The work-up, diagnosis, and characterization of a CSF leak can be complex, often requiring a multimodality approach to optimize surgical planning. This article reviews the causes of CSF leaks, describes the methodology used to work up a suspected leak, and discusses the challenges of making an accurate diagnosis.

Lesions of the Seminal Vesicles and their MRI Characteristics.

Over the past few decades, MRI of the prostate has made great strides in improving cancer detection and is being embraced by more clinicians each day. This article aims to review the imaging characteristics of common and uncommon, but consequential lesions involving the seminal vesicles (SV), as seen predominantly on MRI. Many of these findings are seen incidentally during imaging of the prostate. Anatomy and embryology of the SV will be described which will help illustrate the associations of abnormalities seen. Congenital, infectious, neoplastic, and tumor mimics will be explored in detail, with discussion on clinical presentation and treatment strategies.