Abstract Details

Title Hazy DWI Restriction in Pons on Hyperacute MRI: DWI 'Smog Sign’

Topic Cerebrovascular Disease and Interventional Neurology

Presentation(s) P5 - Poster Session 5 (5:30 PM-6:30 PM)

Poster/Presentation
Number 3-056

Objective To report a case of acute BAO in near locked-in state with “smoggy” Diffusion-weighted imaging (DWI) restriction correlating with Apparent Diffusion Coefficient (ADC) changes in the pons on hyper-acute MRI scan.

Background Not applicable

Design/Methods Not applicable

Results A 62-year-old man presented with somnolence, disorientation, right hemiplegia, left-sided drift, dysarthria, and moderate aphasia. Initial NIHSS was 21, non-contrast CT head was negative for bleed, CTA showed mid-distal Basilar Artery Occlusion (BAO). Alteplase was initiated but the patient condition deteriorated with an obtunded exam, unresponsive pupils, right hemiplegia and left hemiparesis with dysconjugate fixed eyes, suggestive of evolving and near complete locked-in syndrome. Hyper-acute MRI showed true restricted diffusion at entire right anterior inferior cerebellar artery (AICA) multiple punctate areas at bilateral posterior inferior cerebellar artery (PICA) along with hazy pontine involvement with only slight DWI signal changes but prominent ADC darkening in the bulk of pons. Mechanical thrombectomy was successfully completed within five hours of stroke onset. There was occlusion of basilar artery distal to right AICA with no anterograde flow to the superior cerebellar arteries or posterior cerebral arteries bilaterally. He made an excellent recovery and had a mRS of 1 in 3 months. This case focuses on an important point of a ‘smoggy’ DWI changes in brainstem on hyperacute MRI, correlating with a noticeable decrease in ADC, are probably suggestive of partial damage to the neurons depicting only patchy areas of infarction in axons having a potential to regenerate.

Conclusions The early DWI restriction in areas where axonal tracts predominate may appear like a "smog" on DWI with pronounced amplification of ADC that can confuse one in thinking of irreversible brain infarction. As evidenced by this case, emergency physicians, stroke neurologists, and neuro-endovascular experts need to be aware of the “smog” sign in pons or other tract areas to enable prompt treatment.

Authors/Disclosures
Asad Ikram, MD, MBBS PRESENTER	Dr. Ikram has nothing to disclose.
Mudassir Farooqui, MD	Dr. Farooqui has nothing to disclose.
Daniel Vela-Duarte, MD (Palm Beach Neuroscience Institute)	Dr. Vela-Duarte has nothing to disclose.
Syed A. Quadri, MD (Massachusetts General Hospital, Harvard Medical School)	Dr. Quadri has nothing to disclose.
Sajid Suriya, MD	Dr. Suriya has nothing to disclose.
Dinesh V. Jillella, MD (Emory University School of Medicine / Grady Memorial Hospital)	Dr. Jillella has nothing to disclose.
Michel T. Torbey, MD, MPH, FAAN (University of Oklahoma)	Dr. Torbey has nothing to disclose.
Atif Zafar, MD (St. Michael's Hospital (University of Toronto))	Dr. Zafar has nothing to disclose.

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