Hypoxic Ischemic Injury in adult patients post cardiac arrest: A Pictoral essay

Transcription

1 Hypoxic Ischemic Injury in adult patients post cardiac arrest: A Pictoral essay Poster No.: C-0558 Congress: ECR 2013 Type: Authors: Keywords: DOI: Educational Exhibit M. Bhatia; New Delhi/IN Ischemia / Infarction, Acute, Education, MR-Diffusion/Perfusion, MR, Neuroradiology brain, Cardiac /ecr2013/C-0558 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 14

2 Learning objectives To illustrate the spectrum of findings of hypoxic ischemic brain damage in patients resuscitated post cardiac arrest and to use patterns of abnormalities on diffusionweighted imaging (DWI) and quantitative regional apparent diffusion coefficient (ADC) values to predict their clinical outcome. (Fig.1) Images for this section: Page 2 of 14

3 Fig. 1: Diffusion weighted Imaging in a 57 year old male post cardiac arrest resuscitation with bilateral symmetric parieto-occipital cortical hyperintensity. Page 3 of 14

4 Background Advances in cardiopulmonary resuscitation may have increased patient survival rates post cardiac arrest, however many of these patients suffer from global hypoperfusion and brain damage, the severity of which is primarily related to the time from arrest to restoration of spontaneous circulation#1#. Predicting the neurological outcome in cardiac arrest survivors is of increasing importance to critical care teams and family members. Early detection of brain insult is critical to guide management and predict long term prognosis#2#. Global ischemia from cardiac arrest results in cortical laminar necrosis. In adults the primary neuro-imaging modalities include CT and MRI. Neuroimaging findings with CT and conventional MRI in early hypoxic ischemic brain injury may often not be useful as they may be normal or demonstrate subtle abnormalities (Fig.2), underestimating the actual extent of injury in the acute period#3,4,5,6#. Occasionally conventional neuroimaging with CT and MRI (T2-weighted and turboflair images) may depict cerebral edema and reversal of gray/white matter densities#7,8,9,10#. Hyperintense signal on T1-weighted sequences caused by accumulation of denatured proteins in dying cells is usually evident after 2 weeks#7,11#. On the contrary DWI with MRI is extremely sensitive for hypoxic-ischemic damage being evident as bright signal seen on DWI #3, 12, 13#. Thus diffusion weighted MRI allows prompt and reliable identification of areas of cytotoxic edema and laminar necrosis unrecognizable by CT scan and conventional MRI#14#(Fig.3). In addition to diffusionweighted imaging (DWI) that reveals the acute or early subacute findings of global cerebral hypoxia#9, 12#, quantitative assessment of the severity of brain damage can be made by measuring the apparent diffusion coefficient (ADC) #9,10,11, 12#. Affected cerebral cortex demonstrates severely restricted diffusion with mean ADC values of #3 mm2/s, compared with the reported normal ADC value of #3 mm2/ s in cortical gray matter #15#. The deep gray nuclei demonstrate variable and mildly restricted diffusion not as severe as in the cerebral cortical gray matter with a mean ADC value of #3 mm2/s in the caudate nucleus#3#. ADC values in white matter decrease at a much slower rate than the cortical gray matter since the white matter is intrinsically more resistant to ischemia than is gray matter ADC.#16# Images for this section: Page 4 of 14

5 Fig. 1: Diffusion weighted Imaging in a 57 year old male post cardiac arrest resuscitation with bilateral symmetric parieto-occipital cortical hyperintensity. Page 5 of 14

6 Fig. 2: T2 weighted MRI in a patient resuscitated post cardiac arrest illustrates mildly pronounced gray-white matter differentiation. Page 6 of 14

7 Fig. 3: Diffusion weighted Imaging of the same patient in Fig.2 demonstrates cortical bright signal not easily evident on T2 weighted MRI. Page 7 of 14

8 Imaging findings OR Procedure details The patterns and extent of brain injury seen in DWI are associated with clinical outcomes in cardiac arrest survivors#4, 12, 13, 14#. Different regions of the grey matter may be affected in HIE. These include isolated cortical injury, isolated deep grey nuclei injury (including caudate nucleus, putamen, and thalamus), and mixed cortical and deep grey nuclei involvement. Among the cortical injuries the Rolandic (precentral and postcentral), medial occipital, and parietal cortices are more frequent sites often sparing the frontal and temporal cortices (Fig. 4). The mixed pattern of injury involving both cortex and deep grey nuclei often correlates with the most severe brain injury of postcardiac arrest survivors and is likely predictive of an unfavourable outcome#4,12#(fig.5). Other sites that may be involved include the cerebellum, pons, the subcortical white matter#12, 17#. These are associated with poor chances of recovery#4, 12, 13#. Further in addition to the distribution of injuries, quantitative ADC analyses with severely reduced ADC valus are noted in the unfavourable outcome group (Fig.6). ADC values are typically decreased to values ranging from 60% to 80% of normal#13#. Among the grey matter structures, the precentral cortex shows the lowest mean ADC value#9#. Studies have depicted that, in all regions, the mean ADC values of the favourable outcome group is similar to those of the controls. The favourable and unfavorable outcome group have significantly different mean ADC values and percent ADC values than the control group #3, 4#. Images for this section: Page 8 of 14

9 Fig. 4: DWI demonstrates bilateral, symmetric, cortical involvement of the occipital region, one of the common sites of cortical involvement in post cardiac arrest survivors. Page 9 of 14

10 Fig. 5: DWI demonstrates a mixed pattern of injury involving both cortex and deep grey nuclei in a post cardiac arrest survivor patient. The severe brain injury is likely predictive of an unfavorable outcome. Page 10 of 14

11 Fig. 6: ADC map demonstrates severe, uniform, cortical restricted diffusion (mean ADC value, #3 mm2/s as measured in the occipital cortex in this patient) Page 11 of 14

12 Conclusion The pictoral essay depicts the spectrum of neuro imaging findings of patients resuscitated post cardiac arrest and MRI findings that help to evaluate the extent and prognosis of brain injury. Diffusion-weighted MR imaging is the most sensitive imaging modalities in the early hours following injury. It accurately depicts the extent and pattern of injury. A mixed pattern of injury (cortex and the deep grey nuclei) and ADC value of grey matter reduced to less than 80%, is likely to predict an unfavourable outcome. Thus the patterns of brain injury in early diffusion-weighted imaging and the quantitative measurement of regional ADC may be useful for predicting the long term clinical outcome of comatose patients after cardiac arrest. Acknowledgments The author thanks Dr. Divyanka Srivastava for her contribution towards review of literature related to the topic. References 1. Greer DM: Mechanisms of injury in hypoxic-ischemic encephalopathy: implications to therapy. SeminNeurol2006, 26: Levy DE, Caronna JJ, Singer BH, Lapinski RH, Frydman H, Plum F. Predicting outcome from hypoxic-ischemic coma. JAMA 1985; 253: Arbelaez A, Castillo M, Mukherji SK: Diffusion-weighted MR imaging of global cerebral anoxia. AJNR Am J Neuroradiol1999, 20: Wijdicks EF, Campeau NG, Miller GM: MR imaging in comatose survivors of cardiac resuscitation. AJNR Am J Neuroradiol2001, 22: Kawahara H, Takeda Y, Tanaka A, Nagano O, Katayama H, Hirakawa M, Hiraki Y. Does diffusion-weighted magnetic resonance imaging enable detection of early ischemic change following transient cerebral ischemia? J NeurolSci 2000;181:73-81 Page 12 of 14

13 6. Choi SP, Park HK, Park KN, Kim YM, Ahn KJ, Choi KH, Lee WJ, Jeong SK: The density ratio of grey to white matter on computed tomography as an early predictor of vegetative state or death after cardiac arrest. Emerg Med J 2008, 25: Siskas N, Lefkopoulos A, Ioannidis I, Charitandi A, Dimitriadis AS. Cortical laminar necrosis in brain infarcts: serial MRI. Neuroradiology 2003;45: Takahashi S, Higano S, Ishii K, et al. Hypoxic brain damage: cortical laminar necrosis and delayed changes in white matter at sequential MR imaging. Radiology 1993;189: Goto Y, Wataya T, Arakawa Y, et al. Magnetic resonance imaging findings of postresuscitation encephalopathy: sequential change and correlation with clinical outcome. No To Shinkei 2001;53: Sawada H, Udaka F, Seriu N, Shindou K, Kameyama M, Tsujimura M. MRI demonstration of cortical laminar necrosis and delayed white matter injury in anoxic encephalopathy. Neuroradiology 1990;32: Komiyama M, Nakajima H, Nishikawa M, Yasui T. Serial MR observation of cortical laminar necrosis caused by brain infarction. Neuroradiology 1998; 40: Els T, Kassubek J, Kubalek R, Klisch J. Diffusion-weighted MRI during early global cerebral hypoxia: a predictor for clinical outcome? Acta Neurol Scand 2004; 110: Lovblad KO, Wetzel SG, Somon T, Wilhelm K, Mehdizade A, Kelekis A, et al. Diffusion-weighted MRI in cortical ischaemia. Neuroradiology 2004; 46: McKinney AM, Teksam M, Felice R, Casey SO, Cranford R, Truwit CL, Kieffer S: Diffusion-weighted imaging in the setting of diffuse cortical laminar necrosis and hypoxicischemic encephalopathy. AJNR Am J Neuroradiol2004, 25: Helenius J, Soinne L, Perkio J, et al. Diffusion-weighted MR imaging in normal human brains in various age groups. AJNR Am J Neuroradiol 2002;23: Page 13 of 14

14 16. Pierpaoli C, Alger JR, Righini A, et al. High temporal resolution diffusion MRI of global cerebral ischemia and reperfusion. J Cereb Blood Flow Metab 1996;16: Boichot C, Walker PM, Durand C, Grimaldi M, Chapuis S, Gouyon JB, Brunotte F: Term neonate prognoses after perinatal asphyxia: contributions of MR imaging, MR spectroscopy, relaxation times, and apparent diffusion coefficients. Radiology 2006, 239: Personal Information Dr. Mona Bhatia Head of Department Department of Radiodiagnosis and Imaging Fortis Escorts Heart Institute New Delhi, India e mail: mona.bhatia@fortishealthcare.com monavikas@hotmail.com Page 14 of 14