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Acute hepatic encephalopathy: diffusion-weighted and fluid-attenuated inversion recovery findings, and correlation
A M McKinney1, B D Lohman, B Sarikaya
1Department of Radiology, University of Minnesota, Minneapolis, MN 55455, USA. mckinrad@umn.edu
Background And Purpose:
In acute hepatic encephalopathy, MR imaging abnormalities have been described in the PVWM, thalami, and corticospinal tracts. We sought to determine characteristic regions of involvement on FLAIR and DWI, to evaluate their reversibility, and to correlate MR imaging extent with clinical severity.
Materials And Methods:
Twenty patients who presented clinically with acute hepatic encephalopathy and MR imaging <21 days after symptom onset were reviewed retrospectively. Two neuroradiologists recorded involved regions on FLAIR and DWI in each, measured ADC values in affected regions and NAWM, and scored the MR imaging severity/extent. The initial severity (West Haven grade), follow-up clinical severity (degree of improvement), and maximal PAL within ±8 days of MR imaging were recorded and correlated with the MR imaging severity.
Results:
On FLAIR and DWI respectively, there were abnormalities in the thalami (85%, 70%), PLIC (75%, 80%), PVWM (80%, 85%), and DBS (70%, 35%) and diffuse cortical involvement (30%, 25%). There were relatively strong significant (P < .005) correlations of FLAIR (r = 0.680, P = .001) and DWI severity (r = 0.690, P = .001) with PAL, and of PAL with the clinical outcome (r = 0.691, P = .001). Both FLAIR (r = 0.592, P = .006) and DWI (r = 0.487, P = .029) severity correlated moderately with the clinical outcome but were not significant at the P < .005 level after Bonferroni correction.
Conclusions:
Patients with acute hepatic encephalopathy may exhibit characteristic regions of involvement on FLAIR with DWI findings that can be reversible. The MR imaging extent on FLAIR and DWI strongly correlates with the maximal PAL, and PAL correlates well with the clinical outcome. Diffuse cortical involvement has a higher potential for neurologic sequelae but can be reversible.
Insights
Magnetic resonance imaging (MRI) using FLAIR and DWI can identify characteristic brain abnormalities in acute hepatic encephalopathy (AHE). The extent of these MRI findings strongly correlates with clinical severity and patient outcomes.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Acute hepatic encephalopathy (AHE) is associated with MR imaging abnormalities in specific brain regions.
- Previous studies have described involvement in the posterior white matter (PVWM), thalami, and corticospinal tracts.
Purpose of the Study:
- To identify characteristic regions of involvement in AHE using FLAIR and DWI MRI sequences.
- To assess the reversibility of these MR imaging abnormalities.
- To correlate the extent of MR imaging findings with clinical severity.
Main Methods:
- Retrospective review of 20 patients with AHE and recent MR imaging.
- Neuroradiologists recorded involved regions on FLAIR and DWI, measured ADC values, and scored MR imaging severity.
- Correlated MR imaging severity with clinical severity (West Haven grade) and plasma ammonia levels (PAL).
Main Results:
- Abnormalities were common in the thalami, PLIC, PVWM, and DBS on FLAIR and DWI.
- FLAIR and DWI severity showed strong correlations with maximal PAL (P < .005).
- PAL correlated well with clinical outcome (P < .001).
Conclusions:
- Characteristic FLAIR and DWI findings are observed in AHE and can be reversible.
- MR imaging extent correlates strongly with PAL and clinical outcome.
- Diffuse cortical involvement may lead to neurologic sequelae but is potentially reversible.
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