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Rapalino O, Pourvaziri A, Maher M, Jaramillo-Cardoso A, Edlow BL, Conklin J, Huang S, Westover B, Romero JM, Halpern E, Gupta R, Pomerantz S, Schaefer P, Gonzalez RG, Mukerji SS, Lev MH. Clinical, Imaging, and Lab Correlates of Severe COVID-19 Leukoencephalopathy. AJNR Am J Neuroradiol 2021; 42:632-638. [PMID: 33414226 DOI: 10.3174/ajnr.a6966] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 10/28/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND AND PURPOSE 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.
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Affiliation(s)
- O Rapalino
- From the Department of Radiology (O.R., A.P., M.M., A.J.-C., J.C., S.H., J.M.R., R.G., S.P., P.S., R.G.G., M.H.L.)
| | - A Pourvaziri
- From the Department of Radiology (O.R., A.P., M.M., A.J.-C., J.C., S.H., J.M.R., R.G., S.P., P.S., R.G.G., M.H.L.)
| | - M Maher
- From the Department of Radiology (O.R., A.P., M.M., A.J.-C., J.C., S.H., J.M.R., R.G., S.P., P.S., R.G.G., M.H.L.)
| | - A Jaramillo-Cardoso
- From the Department of Radiology (O.R., A.P., M.M., A.J.-C., J.C., S.H., J.M.R., R.G., S.P., P.S., R.G.G., M.H.L.)
| | | | - J Conklin
- From the Department of Radiology (O.R., A.P., M.M., A.J.-C., J.C., S.H., J.M.R., R.G., S.P., P.S., R.G.G., M.H.L.)
| | - S Huang
- From the Department of Radiology (O.R., A.P., M.M., A.J.-C., J.C., S.H., J.M.R., R.G., S.P., P.S., R.G.G., M.H.L.)
| | | | - J M Romero
- From the Department of Radiology (O.R., A.P., M.M., A.J.-C., J.C., S.H., J.M.R., R.G., S.P., P.S., R.G.G., M.H.L.)
| | - E Halpern
- Institute for Technology Assessment (E.H.), Massachusetts General Hospital, Boston, Massachusetts
| | - R Gupta
- From the Department of Radiology (O.R., A.P., M.M., A.J.-C., J.C., S.H., J.M.R., R.G., S.P., P.S., R.G.G., M.H.L.)
| | - S Pomerantz
- From the Department of Radiology (O.R., A.P., M.M., A.J.-C., J.C., S.H., J.M.R., R.G., S.P., P.S., R.G.G., M.H.L.)
| | - P Schaefer
- From the Department of Radiology (O.R., A.P., M.M., A.J.-C., J.C., S.H., J.M.R., R.G., S.P., P.S., R.G.G., M.H.L.)
| | - R G Gonzalez
- From the Department of Radiology (O.R., A.P., M.M., A.J.-C., J.C., S.H., J.M.R., R.G., S.P., P.S., R.G.G., M.H.L.)
| | | | - M H Lev
- From the Department of Radiology (O.R., A.P., M.M., A.J.-C., J.C., S.H., J.M.R., R.G., S.P., P.S., R.G.G., M.H.L.)
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Ping Y, Kemp AJ, Divol L, Key MH, Patel PK, Akli KU, Beg FN, Chawla S, Chen CD, Freeman RR, Hey D, Higginson DP, Jarrott LC, Kemp GE, Link A, McLean HS, Sawada H, Stephens RB, Turnbull D, Westover B, Wilks SC. Dynamics of relativistic laser-plasma interaction on solid targets. Phys Rev Lett 2012; 109:145006. [PMID: 23083255 DOI: 10.1103/physrevlett.109.145006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Indexed: 06/01/2023]
Abstract
A novel time-resolved diagnostic is used to record the critical surface motion during picosecond-scale relativistic laser interaction with a solid target. Single-shot measurements of the specular light show a redshift decreasing with time during the interaction, corresponding to a slowing-down of the hole boring process into overdense plasma. On-shot full characterization of the laser pulse enables simulations of the experiment without any free parameters. Two-dimensional particle-in-cell simulations yield redshifts that agree with the data, and support a simple explanation of the slowing-down of the critical surface based on momentum conservation between ions and reflected laser light.
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Affiliation(s)
- Y Ping
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
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Krauland CM, Jarrott LC, Drake RP, Keiter PA, Kuranz CC, Westover B, Sawada H, Kaczala DN, Bonofiglo P. An evaluation of high energy bremsstrahlung background in point-projection x-ray radiography experiments. Rev Sci Instrum 2012; 83:10E528. [PMID: 23127035 DOI: 10.1063/1.4738649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Backlit pinhole x-ray radiography has provided high-resolution images in many recent high-energy-density laser experiments. Its aim is to image the object of interest with a roughly monochromatic Kα source. However, despite the high intrinsic brightness achieved by the technique, data on x-ray film have shown a signal to background ratio near one, with data on image plates producing a higher background. This has been attributed, without direct evidence, to the interaction of suprathermal electrons with the (high Z) pinhole substrate. We present here the first direct measurement of the hard x-rays produced by such a backlighter target and a test of an approach to reducing the background. Specifically, a thick, low-Z layer was added on the side of the substrate toward the detector, intended to stop the energetic electrons and produce smaller emissions. Results from the Omega-60 laser experiment showed that the oft-seen background signal is in the range of 60-80 keV, a plausible energy range for energetic electrons produced in the laser-irradiated plasma. It also showed a comparable level of background signal in both types of targets. The work presented here includes target design and motivating theory, as well as the unexpected findings about x-ray background production.
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Affiliation(s)
- C M Krauland
- Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA.
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