Infarction limited to both middle cerebellar peduncles

Clinical, Imaging, and Lab Correlates of Severe COVID-19 Leukoencephalopathy

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.

Bilateral middle cerebellar peduncle lesions: Neuroimaging features and differential diagnoses

OBJECTIVES

Lesions limited to the bilateral middle cerebellar peduncles (MCPs) are uncommon. This retrospective study investigated diseases with a proclivity for the bilateral MCPs and explored the associations between their neuroimaging features and clinical findings for the differential diagnosis of such lesions.

METHODS

We enrolled 26 patients who were admitted to our department between January 2016 and March 2019 with bilateral MCP abnormalities on magnetic resonance imaging (MRI). The demographic, clinical, and neuroimaging characteristics, and the biomarkers and diagnoses were evaluated.

RESULTS

Although all patients exhibited symmetrical bilateral MCP hypointensities on T1-weighted imaging and hyperintensities on T2-weighted and fluid-attenuated inversion recovery imaging, they were diagnosed with different conditions. Diagnoses included acute cerebral infarction (ACI) (n = 9, 34.62%), Wallerian degeneration (WD) (n = 8, 30.77%), multiple system atrophy (MSA) (n = 6, 23.08%), neuromyelitis optica (NMO) (n = 1, 3.85%), heroin-induced leukoencephalopathy (n = 1, 3.85%), and primary central nervous system lymphoma (PCNSL) (n = 1, 3.85%). Patients with ACI exhibited bilateral MCP-restricted diffusion hyperintensities on diffusion-weighted imaging and corresponding stenosis or occlusion of the vertebrobasilar system. The initial MRI of patients with WD depicted pontine infarctions, while symmetrical MCP lesions were observed on follow-up MRI. Symmetrical MCP lesions, cruciform hyperintensity, and marked atrophy in the posterior fossa were characteristic manifestations of MSA. Longitudinally extensive myelitis affecting more than three vertebral segments on cervical MRI and positive serum AQP4-IgG may be indicative of NMO. Heroin-induced leukoencephalopathy was characterized by extra-symmetrical lesions in the posterior limbs of the internal capsules, while the anterior limbs were spared. PCNSL was indicated by a significant and characteristic "fist" sign on contrast-enhanced MRI.

CONCLUSIONS

Bilateral MCP lesions were most frequently observed in cerebrovascular diseases, followed by neurodegenerative diseases, inflammatory diseases, toxic encephalopathies, and lymphomas. Our findings demonstrate that bilateral MCP signal abnormalities are more common in patients with ACI and WD, with fewer degenerative processes than previously believed. The high frequency of WD may be attributed to the specific awareness of this pathology. WD can also present with stage-related restricted diffusion and should not be mistaken for a new infarction. The symmetrical bilateral MCP hypointensities on T1-weighted imaging and hyperintensities on T2-weighted imaging often raise concern regarding a demyelinating process. Our findings emphasize that neurologists should consider the aforementioned conditions and correlate the specific neuroimaging characteristics and medical history before arriving at the final diagnosis.

Evaluation of Clinical Features and Stroke Etiology in Patients with Bilateral Middle Cerebellar Peduncle Infarction

OBJECTIVE

The aim of this study was to characterize clinical features, etiologies, and mechanisms of strokes due to bilateral middle cerebellar peduncle infarction (BMCPI).

METHODS

Cases diagnosed as BMCPI in our hospital were retrieved, and a literature review was performed. Data on clinical features and brain MRI were obtained. Extracranial and intracranial segments of the vertebrobasilar artery were assessed by using digital subtraction angiography, magnetic resonance angiography, or computed tomography angiography.

RESULTS

Thirteen cases (11 men and 2 women) of BMCPI were identified. A high-intensity signal of diffusion-weighted imaging sequence involving the bilateral middle cerebellar peduncle was observed in all patients. Most patients experienced vertigo, dysarthria, ataxia, and hearing disorders. Eleven of these cases were classified as large artery atherosclerosis, one as traumatic vertebral artery (VA) dissection, and one as giant cell arteritis.

CONCLUSION

BMCPI is a rare cerebrovascular disease characterized by vertigo, ataxia, and dysarthria, which may also be accompanied by a hearing deficit or clinical signs of brainstem damage. BMCPI may be associated with hypoperfusion secondary to occlusive disease of the bilateral VA or proximal basilar artery.

Bilateral wallerian degeneration of the middle cerebellar peduncles secondary to pontine infarction: A case series

OBJECTIVE

Wallerian degeneration (WD) of middle cerebellar peduncles (MCPs) secondary to pontine infarction is rarely reported in the literature. Our aim in this study is to characterize its clinical and neuroradiological features.

METHODS

A retrospective review of 7 patients from a single institution was conducted. Only patients with pontine infarction and subsequent degeneration of the MCPs were included in the analysis. The features of clinical presentation and neuroimaging finding were summarized by our experienced neurologists.

RESULTS

Seven patients (5 male, 2 female), ranging in age from 50 to 77 years, satisfied the inclusion criteria. All patients had cardiovascular risk factors and hypertension was the most common one. Almost all of the patients had hemiparesis and dysarthria, and could achieved good clinical outcome. On the initial scan, hyperintense on T2- and diffusion-weighted images suggested the acute pontine infarction. On the follow-up scan, however, hyperintensities of bilateral MCPs on T2-weight and FLAIR images were apparently demonstrated in all patients. The specific lesions in the MCPs were attributed to bilateral WD of the pontocerebellar fibres secondary to pontine infarction.

CONCLUSION

WD should be taken into account when patients are initially diagnosed with paramedian pontine infarction and follow-up MRI manifest as symmetrical hyperintense in the MCPs.

The endovascular treatment of bilateral infarction of middle cerebellar peduncles. Etiology and endovascular treatment analysis

Infarction of the symmetrical middle cerebellar peduncles is often induced by ischemic cerebrovascular disease. Adams described the anterior inferior cerebellar artery (AICA) syndrome as early as 1943, but clinical and imaging studies following this failed to shed more light regarding the condition until the advent of magnetic resonance imaging that comprehension regarding AICA improved significantly. Infarction of the middle cerebellar peduncles (MCP) is uncommon and the endovascular treatment of this condition is even more rare. We studied 4 patients with simultaneous bilateral cerebellar infarction of whom 2 received intracranial vascular therapy and demonstrated improvement in symptoms. Our findings suggest that patients with vertebral basilar artery stenosis with potential bilateral cerebellar infarction may benefit from endovascular treatment.

Microvascular anatomy of the cerebellar parafloccular perforating space

OBJECT

The cerebellopontine angle is a common site for tumor growth and vascular pathologies requiring surgical manipulations that jeopardize cranial nerve integrity and cerebellar and brainstem perfusion. To date, a detailed study of vessels perforating the cisternal surface of the middle cerebellar peduncle—namely, the paraflocculus or parafloccular perforating space—has yet to be published. In this report, the perforating vessels of the anterior inferior cerebellar artery (AICA) in the parafloccular space, or on the cisternal surface of the middle cerebellar peduncle, are described to elucidate their relevance pertaining to microsurgery and the different pathologies that occur at the cerebellopontine angle.

METHODS

Fourteen cadaveric cerebellopontine cisterns (CPCs) were studied. Anatomical dissections and analysis of the perforating arteries of the AICA and posterior inferior cerebellar artery at the parafloccular space were recorded using direct visualization by surgical microscope, optical histology, and scanning electron microscope. A comprehensive review of the English-language and Spanish-language literature was also performed, and findings related to anatomy, histology, physiology, neurology, neuroradiology, microsurgery, and endovascular surgery pertaining to the cerebellar flocculus or parafloccular spaces are summarized.

RESULTS

A total of 298 perforating arteries were found in the dissected specimens, with a minimum of 15 to a maximum of 26 vessels per parafloccular perforating space. The average outer diameter of the cisternal portion of the perforating arteries was 0.11 ± 0.042 mm (mean ± SD) and the average length was 2.84 ± 1.2 mm. Detailed schematics and the surgical anatomy of the perforating vessels at the CPC and their clinical relevance are reported.

CONCLUSIONS

The parafloccular space is a key entry point for many perforating vessels toward the middle cerebellar peduncle and lateral brainstem, and it must be respected and protected during surgical approaches to the cerebellopontine angle.

Cerebellar mutism and reversible cytotoxic edema in influenza B-associated encephalopathy

BACKGROUND

Influenza virus-associated neurological complications are rare, though well-documented, especially in children. Encephalopathy and seizures are the most common complications and are typically associated with influenza A infection. Cerebellar mutism has been rarely reported in association with influenza B infection.

PATIENT

We describe a 3-year-old boy who presented with cough, fever, altered mental status, seizure, hypotonia, and mutism. He tested positive for influenza B virus. His brain magnetic resonance imaging showed reversible cytotoxic edema limited to the middle cerebellar peduncles and the dentate nuclei. Other viral, vascular, toxic, and metabolic causes were ruled out.

CONCLUSION

Our patient represents a case of cerebellar mutism associated with influenza B encephalopathy in which the brain magnetic resonance imaging scan showed reversible cytotoxic edema limited to the middle cerebellar peduncles and the dentate nuclei. This clinicoradiological correlation supports other reports in which the dentate nuclei play a major rule in the pathogenesis of cerebellar mutism.

Hot cross bun sign following bilateral pontine infarction: a case report

The hot cross bun sign is characterized by cruciform T2 signal hyperintensity in the pons and has been reported to be a specific but not pathognomic for multiple system atrophy. It reflects degeneration of pontine neurons and transverse pontocerebellar fibers, regardless of the underlying pathogenic process. Here, we report a case of hot cross bun sign following bilateral pontine infarction due to Wallerian degeneration of the pontocerebellar fibers.