To test whether the relationship between acute ischemic infarct size on concurrent computed tomographic (CT) angiography source images and diffusion-weighted (DW) magnetic resonance images is dependent on the parameters of CT angiography acquisition protocols.This retrospective study had institutional review board approval, and all records were HIPAA compliant. Data in 100 patients with anterior-circulation acute ischemic stroke and large vessel occlusion who underwent concurrent CT angiography and DW imaging within 9 hours of symptom onset were analyzed. Measured areas of hyperintensity at acute DW imaging were used as the standard of reference for infarct size. Information regarding lesion volumes and CT angiography protocol parameters was collected for each patient. For analysis, patients were divided into two groups on the basis of CT angiography protocol differences (patients in group 1 were imaged with the older, slower protocol). Intermethod agreement for infarct size was evaluated by using the Wilcoxon signed rank test, as well as by using Spearman correlation and Bland-Altman analysis. Multivariate analysis was performed to identify predictors of marked (≥20%) overestimation of infarct size on CT angiography source images.In group 1 (n=35), median hypoattenuation volumes on CT angiography source images were slightly underestimated compared with DW imaging hyperintensity volumes (33.0 vs 41.6 mL, P=.01; ratio=0.83), with high correlation (ρ=0.91). In group 2 (n=65), median volume on CT angiography source images was much larger than that on DW images (94.8 vs 17.8 mL, P<.0001; ratio=3.5), with poor correlation (ρ=0.49). This overestimation on CT angiography source images would have inappropriately excluded from reperfusion therapy 44.4% or 90.3% of patients eligible according to DW imaging criteria on the basis of a 100-mL absolute threshold or a 20% or greater mismatch threshold, respectively. Atrial fibrillation and shorter time from contrast material injection to image acquisition were independent predictors of marked (≥20%) infarct size overestimation on CT angiography source images.CT angiography protocol changes designed to speed imaging and optimize arterial opacification are associated with significant overestimation of infarct size on CT angiography source images.
Patients infected with the Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) can develop a spectrum of neurological disorders, including a leukoencephalopathy of variable severity. Our aim was to characterize imaging, lab, and clinical correlates of severe coronavirus disease 2019 (COVID-19) leukoencephalopathy, which may provide insight into the SARS-CoV-2 pathophysiology.
MATERIALS AND METHODS:
Twenty-seven consecutive patients positive for SARS-CoV-2 who had brain MR imaging following intensive care unit admission were included. Seven (7/27, 26%) developed an unusual pattern of "leukoencephalopathy with reduced diffusivity" on diffusion-weighted MR imaging. The remaining patients did not exhibit this pattern. Clinical and laboratory indices, as well as neuroimaging findings, were compared between groups.
RESULTS:
The reduced-diffusivity group had a significantly higher body mass index (36 versus 28 kg/m2, P < .01). Patients with reduced diffusivity trended toward more frequent acute renal failure (7/7, 100% versus 9/20, 45%; P = .06) and lower estimated glomerular filtration rate values (49 versus 85 mL/min; P = .06) at the time of MRI. Patients with reduced diffusivity also showed lesser mean values of the lowest hemoglobin levels (8.1 versus 10.2 g/dL, P < .05) and higher serum sodium levels (147 versus 139 mmol/L, P = .04) within 24 hours before MR imaging. The reduced-diffusivity group showed a striking and highly reproducible distribution of confluent, predominantly symmetric, supratentorial, and middle cerebellar peduncular white matter lesions (P < .001).
CONCLUSIONS:
Our findings highlight notable correlations between severe COVID-19 leukoencephalopathy with reduced diffusivity and obesity, acute renal failure, mild hypernatremia, anemia, and an unusual brain MR imaging white matter lesion distribution pattern. Together, these observations may shed light on possible SARS-CoV-2 pathophysiologic mechanisms associated with leukoencephalopathy, including borderzone ischemic changes, electrolyte transport disturbances, and silent hypoxia in the setting of the known cytokine storm syndrome that accompanies severe COVID-19.
To determine the diagnostic yield of multidetector computed tomographic (CT) angiography in the evaluation of patients presenting to the emergency department with acute blunt head and neck trauma to assess for arterial injury and to propose a practical scoring system for the identification of patients at highest risk of arterial injury.With institutional review board approval, Health Insurance Portability and Accountability Act compliance, and waived informed consent, a retrospective study was conducted of 830 consecutive patients who presented to the emergency department with acute blunt head and neck trauma over 9 years and were evaluated with multidetector CT angiography. Unenhanced CT scans and CT angiograms were reviewed for the presence of cervical interfacetal subluxations and/or dislocations, fractures, intracranial hemorrhage, and arterial injury. Medical records were reviewed for mechanism of injury (MOI). Multivariate logistic regression analysis was performed to identify independent predictors of an increased risk of arterial injury.Multidetector CT angiographic results showed injury to 118 arterial structures in 106 (12.8%) patients. Multivariate logistic regression analysis showed that the presence of cervical interfacetal subluxation/dislocations (44.4%; odds ratio [OR], 6.3; P < .0001), fracture lines reaching an arterial structure (22.1%; OR, 4.4; P < .0001), and high-impact MOIs (16.5%; OR, 3.1; P < .0001) were independent predictors of an increased risk of arterial injury and were used to construct a scoring system. Patients with scores of 2 and 3 (21.9% and 52.2%, respectively) were at highest risk of arterial injury.The proposed acute craniocervical trauma scoring system could be used as a guide to select blunt trauma patients for multidetector CT angiographic evaluation. Future validation of this scoring system is necessary.
A 35-year-old man was seen in the emergency department of this hospital because of neck pain, hoarseness, and dysphagia that developed during exertion 1 week earlier, recurred intermittently, and then persisted. A diagnostic procedure was performed.
Stroke is the third leading cause of death and is a major cause of long-term disability. Neuroprotective treatment within a 4-hour «therapeutic window» has proved highly efficacious in reducing morbility and mortality in animal model. It is with this background that the need for emergent diagnosis and therapy of acute stroke in strongly suggested. Computed tomography (CT) shows the parenchymal changes of acute stroke too late to be helpful, and its role has been primarily to evaluate the possibility of intracerebral or subarachnoid hemorrhage. While conventional magnetic resonance (MR) imaging can demonstrate parenchymal abnormalities 4–6 hours after ischemia, newer techniques such as diffusion-weighted MR imaging (DWI) hold promise that a diagnosis of ischemia can be made within minutes after the acute event. In this article compares different aspects of hyperacute cerebral ischemia depicted at diffusion-weighted imaging before infarction is depicted at conventional MR or CT scans. DWI techniques may improve stroke diagnosis and may contribute to advances in treatment.
BACKGROUND AND PURPOSE: We hypothesized that, in acute cerebral ischemic stroke, anisotropic diffusion increases if T2 signal intensity is not substantially elevated and decreases once T2 hyperintensity becomes apparent. Our purpose was to correlate fractional anisotropy (FA) measurements with the clinical time of stroke onset, apparent diffusion coefficients (ADC), and T2 signal intensity. METHODS: Tensor diffusion-weighted images (DWIs) of 25 patients were obtained within 12 hours of symptom onset. Trace DWIs, ADCs, FAs, and echo-planar T2-weighted images (T2WI) were generated. Stroke and contralateral normal volumes of interest (VOIs) were outlined on DWIs and projected onto the inherently coregistered ADC map, FA map, and echo-planar T2WI. Mean signal intensity of the ischemic and contralateral normal VOIs were compared for relatives change in ADC, FA, and signal intensity on T2WIs. RESULTS: A significant negative correlation was observed between FA and T2 signal-intensity change (r = −0.61, P = .00009). A trend of correlation between FA signal intensity and time of onset were found (r = −0.438, P = .025). No significant correlation was found between ADC and FA values (r = −0.302, P = .134). The mean ADC reduction in the ipsilateral ischemic volume was 31% ± 11 compared with the contralateral normal side. CONCLUSION: Change in FA is inversely correlated with T2 signal intensity and, to a lesser extent, the time of onset, but it is not well correlated with ADC values in the acute stage.
A 69-year-old man was admitted to this hospital because of dizziness and vomiting, which had begun abruptly 9 hours earlier, on awakening. Examination revealed nystagmus and a wide-based gait. CT revealed no intracranial hemorrhage. A diagnostic procedure was performed.
A 56-year-old woman had dizziness and nausea, followed by slurred speech and ataxia; 2 months later she was unable to walk. Neurologic examination disclosed severe ataxia. Imaging studies of the brain did not show discrete parenchymal lesions or vascular occlusion; there was cerebellar atrophy. A diagnostic procedure was performed.
Effect of CCR-5 delta 32 heterozygosity in immunological protection was studied by a lymphocyte proliferation assay. Twenty of 86 HIV+ and eight of 32 healthy subjects showed heterozygous mutation (wt/mut) of the CCR-5 gene. Lymphocyte proliferation to pokeweed mitogen was found significantly higher (P < 0.005) in wt/mut versus wild type homozygous (wt/wt) HIV+ subjects in groups with CD4 > 500 and CD4 < 200 cell/ micro L. Phytohaemagglutinin induced stronger proliferation of cells from wt/mut HIV+ subjects with CD4 < 200 cell/ micro L (P = 0.03). Decline of lymphocyte response was more significant among wt/wt groups with different CD4+ cell counts than that between wt/mut groups to both mitogens. Reduced number of CCR-5 receptors on CD4+ cells may decrease the ability of HIV-1 envelope glycoproteins to transduce intracellular signals through CCR-5. Mutation in CCR-5 gene seems to have a benefit in preventing T-cells from HIV envelope-mediated immunopathogenic effects and maintain a relatively normal response to lectins.
