Delineation of microhemorrhage in acute hepatic encephalopathy using susceptibility-weighted imaging

Spectrum of Neuroimaging Abnormalities in Brain in Patients of Acute-on-Chronic Liver Failure

Background and aims

Acute-on-chronic liver failure (ACLF) is associated with high short-term mortality. There is a paucity of data about the spectrum of neuroimaging abnormalities in the brain in ACLF patients. The present study was aimed to study the prevalence of cerebral edema and other parenchymal changes in MR imaging of the brain in patients with ACLF.

Methods

In this prospective observational study, MR imaging was done in patients with ACLF (n = 41), and findings were compared with age and sex-matched patients with acute decompensation (AD) (n = 13) and those with cirrhosis but without any decompensation at recruitment (n = 21).

Results

Forty-one patients with ACLF (24.4% Grade 1 and Grade 2, 51.2% Grade 3) with 14 (34.1%) having cerebral failure were included in the study. T2-weighted (T2W) diffuse white matter hyperintensities (WMHs) and focal WMHs were seen in 17 (41.4%) and 7 (17%) patients, respectively. T1W basal ganglia hyperintensities in 20 (48.7%), cerebral microbleeds (CMBs) in 6 (14.6%), and 2 (4.8%) patients had cerebral edema. In patients with AD, T2W diffuse WMHs were seen in 3 (23%), T2W focal WMHs in 3 (23%) patients. None of the patients with AD had cerebral edema or CMBs. In compensated cirrhosis patients, T2W diffuse WMHs were present in 7 (33.3%), T2W focal WMHs in 5 (23.8%), while 3 (14.2%) patients had CMBs. T1 weighted hyperintensities in basal ganglia were more common in AD [9 (69.2%)] and compensated cirrhosis [15 (71.4%)] as compared to ACLF patients [20 (48.7%)], P = 0.174. The survival time of 30 and 90 days for patients with diffuse T2W WMHs was significantly lesser than patients without T2W WMHs (P = 0.007).

Conclusion

Cerebral edema is uncommon in ACLF patients, and T2-weighted diffuse white matter hyperintensities may be associated with worse outcomes. However, due to the limited scope of the present study, the same needs to be explored further in larger cohorts.

Potentially Reversible and Recognizable Acute Encephalopathic Syndromes: Disease Categorization and MRI Appearances

"Encephalopathy" is a vague term that encompasses varying definitions, often with a nonspecific clinical presentation and numerous possible pathophysiologic causes. Hence, MR imaging plays a crucial role in the early diagnosis and treatment by identifying imaging patterns when there is limited clinical history in such patients with acute encephalopathy. The aim of this review was to aid in remembrance of etiologies of potentially reversible acute encephalopathic syndromes on MR imaging. The differential includes vascular (reversible cerebral vasoconstriction syndrome, transient global amnesia, disseminated intravascular coagulation, and thrombotic microangiopathy), infection (meningitis, encephalitis), toxic (posterior reversible encephalopathy syndrome, acute toxic leukoencephalopathy; carbon monoxide, alcohol-related, medication- and illicit drug-related toxic encephalopathies), autoimmune, metabolic (osmotic demyelination syndrome, uremic, acute hepatic encephalopathy), idiopathic/inflammatory (stroke-like migraine attacks after radiation therapy syndrome), neoplasm-related encephalopathy, and seizure-related encephalopathy.

"CHOICES": An acronym to aid in delineating potential causes of non-metabolic, non-infectious acute toxic leukoencephalopathy

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Recognition the etiologies of ATL is important due to its potentially reversible nature after treatment or removal of the toxin.

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“CHOICES” is useful to memorize etiologies associated with PVWM injury in non-metabolic and non-infectious ATL patients.

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Reduced diffusion is an early and important imaging finding to evaluate patients with non-metabolic and non-infectious ATL patients.

Purpose

To describe non-metabolic, non-infectious etiologies of acute toxic leukoencephalopathy (ATL) on DWI MRI, and provide a useful acronym to remember them.

Material and Methods

Our PACS archive was reviewed, yielding 185 patients with suspected ATL per MRI reports and clinical follow up; infectious or metabolic causes were excluded.

Result/Discussion

The 87 included non-infectious, non-metabolic ATL patients' etiologies are represented by the acronym 'CHOICES': chemotherapy ('C',n = 34); heroin-induced ('H',n = 6), opioid analogues ('O',n = 14); immunosuppressant ('I',n = 11) or imidazole (n = 2); cocaine ('C',n = 1); environmental or ethanol abuse ('E',n = 5), splenial lesions ('S',n = 9), and 'other' (n = 5).

Conclusion

The "CHOICES" acronym delineates various toxic etiologies of ATL.

Acute Toxic Leukoencephalopathy: Etiologies, Imaging Findings, and Outcomes in 101 Patients

BACKGROUND AND PURPOSE

Prior studies regarding acute toxic leukoencephalopathy (ATL) are either small, or preliminary. Our aim was to evaluate etiologies of and differences in imaging severity and outcomes among various etiologies of ATL.

MATERIALS AND METHODS

MRIs of patients with suspected ATL over 15 years were retrospectively reviewed; inclusion criteria were: MRI <3 weeks of presentation with both DWI and FLAIR. These were jointly graded by two neuroradiologists via a previously described score of severity. Clinical outcome was evaluated via both modified Rankin (mRS) and ATL outcome (ATLOS) scores, each being correlated with the DWI and FLAIR scores. Etiologic subgroups of n > 6 patients were statistically compared.

RESULTS

Of 101 included patients, the 4 subgroups of n > 6 were the following: chemotherapy (n = 35), opiates (n = 19), acute hepatic encephalopathy (n = 14), and immunosuppressants (n = 11). Other causes (n = 22 total) notably included carbon monoxide (n = 3) metronidazole (n = 2), and uremia (n = 1). The mean DWI/FLAIR severity scores were 2.6/2.3, 3.3/3.3, 2.1/2.1 and 2.0/2.5 for chemotherapeutics, opiates, AHE and immunosuppressants, respectively, with significant differences in both imaging severity and outcome (P = .003-.032) among subgroups, particularly immunosuppressant versus chemotherapy-related ATL and immunosuppressants versus opiates (P = .004-.032) related ATL. DWI and FLAIR severity weakly correlated with outcome (ρ = 0.289-.349, P < .005) but correlated stronger in the chemotherapy (ρ = 0.460-.586, P < .010) and opiate (ρ =.472-.608, P < .05) subgroups, which had the worst outcomes. ATL clinically resolved in 36%, with severe outcomes in 23% (coma or death, 9/16 deaths from fludarabine). Notable laboratory results were elevated CSF myelin basic protein levels in 8/9 patients and serum blood urea nitrogen levels in 24/91.

CONCLUSIONS

Clinical outcomes of ATL vary on the basis of etiology, being worse in chemotherapeutic- and opiate-related ATL. Uremia may be a predisposing or exacerbating factor.

Susceptibility Etching on MRI in Patients with Microangiopathy

BACKGROUND

We detected a novel imaging sign, which consists of a specific imaging pattern of diffuse susceptibility effect, delineating the cortical-subcortical junction on high-resolution susceptibility-weighted images (SWIs). We describe magnetic resonance imaging findings in 10 patients with "susceptibility etching" and possible association with their abnormal coagulation profile.

MATERIALS/METHODS

A retrospective case series study with a search for cases that demonstrated susceptibility effect at the cortical-subcortical junction on SWI sequences was performed. The patients' respective coagulation profiles including prothrombin time, partial thromboplastin time, fibrinogen, D-dimer values, and platelet counts were reviewed. In addition, clinical history and neurological deficits were recorded.

RESULTS

We identified 10 patients with the "susceptibility etching" pattern at the cortical-subcortical junction. All patients were acutely ill and had a significantly elevated D-dimer (4,309 mcg/L to >10,000 mcg/L) with variably reduced platelet count. Two patients had reduced fibrinogen and 5 patients had prolonged international normalized ratio. Of the 10 patients, 4 died during hospitalization, within a few days of imaging. Pathology of 1 patient at autopsy demonstrated findings suggestive of a microvascular thrombotic or embolic event without overt parenchymal microhemorrhage.

CONCLUSION

In this preliminary case series, we describe patients with "susceptibility etching" on SWI who were also found to have profound coagulation impairment. While other comorbities may also contribute to this novel sign, we suggest that a possible etiology may be secondary to microvascular in situ formation of fine thrombi and/or emboli lodged into an area of vascular caliber reduction and maybe related to thrombotic microangiopathy.