Application of susceptibility weighted imaging (SWI) in diagnostic imaging of brain pathologies – a practical approach

Isolated leptomeningeal angiomatosis in Sturge-weber syndrome type III: A case report with distinctive neuroimaging features

Sturge-Weber syndrome type III (SWS-III) is the rarest variant of SWS, characterized by isolated leptomeningeal angiomatosis without cutaneous or ophthalmological manifestations. We report the case of an 11-year-old female who developed drug-resistant epilepsy at 18 months of age and mild left hemiparesis. Despite multiple anticonvulsant medications, seizures remained poorly controlled. Brain imaging revealed characteristic findings of right cerebral hemihypotrophy, cortical calcifications, and leptomeningeal enhancement without facial port-wine stain or ophthalmological involvement. These distinctive radiological features led to the diagnosis of SWS-III. This case highlights the crucial role of neuroimaging in diagnosing SWS-III, where external clinical markers are absent. Recognition of specific radiological patterns is essential for accurate diagnosis and appropriate management.

Susceptibility-Weighted Imaging (SWI): Technical Aspects and Applications in Brain MRI for Neurodegenerative Disorders

Susceptibility-weighted imaging (SWI) is a magnetic resonance imaging (MRI) sequence sensitive to substances that alter the local magnetic field, such as calcium and iron, allowing phase information to distinguish between them. SWI is a 3D gradient-echo sequence with high spatial resolution that leverages both phase and magnitude effects. The interaction of paramagnetic (such as hemosiderin and deoxyhemoglobin), diamagnetic (including calcifications and minerals), and ferromagnetic substances with the local magnetic field distorts it, leading to signal changes. Neurodegenerative diseases are typically characterized by the progressive loss of neurons and their supporting cells within the neurovascular unit. This cellular decline is associated with a corresponding deterioration of both cognitive and motor abilities. Many neurodegenerative disorders are associated with increased iron accumulation or microhemorrhages in various brain regions, making SWI a valuable diagnostic tool in clinical practice. Suggestive SWI findings are known in Parkinson's disease, Lewy body dementia, atypical parkinsonian syndromes, multiple sclerosis, cerebral amyloid angiopathy, amyotrophic lateral sclerosis, hereditary ataxias, Huntington's disease, neurodegeneration with brain iron accumulation, and chronic traumatic encephalopathy. This review will assist radiologists in understanding the technical framework of SWI sequences for a correct interpretation of currently established MRI findings and for its potential future clinical applications.

Reproducible occurrence of hiccups during resection of a large pontine cavernous malformation

Background

Various brainstem pathologies cause hiccups.

Case Description

A 45-year-old man with cerebral cavernous malformation (CCM) in the pons, identified at the age of 25 years, experienced an exacerbation of left hemiparesis. The patient presented with left oculomotor and facial nerve paresis, trigeminal pain, and swallowing disturbances, though hiccups were not observed. Cerebral magnetic resonance imaging revealed a hemorrhagic mass occupying the dorsal pons, predominantly on the right side, along with multiple hemosiderin deposits in the cerebral and cerebellar hemispheres. The patient underwent a microsurgical CCM resection. Intraoperatively, traction maneuvers on the CCM, which severely adhered to the right lower pons, reproducibly caused intense hiccups. The hiccups resolved within minutes of the release of traction. Genomic analysis of CCM identified CCM1 mutation. Postoperatively, the patient had no recurrence of hiccups.

Conclusion

Surgical resection of large pontine CCMs can cause intraoperative hiccups, potentially hindering the continuation of surgery. Despite common genomic mutations, multiple CCMs may exhibit diverse biological behaviors.

Changes in iron load in specific brain areas lead to neurodegenerative diseases of the central nervous system

The causes of neurodegenerative diseases remain largely elusive, increasing their personal and societal impacts. To reveal the causal effects of iron load on Parkinson's disease (PD), Alzheimer's disease (AD), amyotrophic lateral sclerosis and multiple sclerosis, we used Mendelian randomisation and brain imaging data from a UK Biobank genome-wide association study of 39,691 brain imaging samples (predominantly of European origin). Using susceptibility-weighted images, which reflect iron load, we analysed genetically significant brain regions. Inverse variance weighting was used as the main estimate, while MR Egger and weighted median were used to detect heterogeneity and pleiotropy. Nine clear associations were obtained. For AD and PD, an increased iron load was causative: the right pallidum for AD and the right caudate, left caudate and right accumbens for PD. However, a reduced iron load was identified in the right and left caudate for multiple sclerosis, the bilateral hippocampus for mixed vascular dementia and the left thalamus and bilateral accumbens for subcortical vascular dementia. Thus, changes in iron load in different brain regions have causal effects on neurodegenerative diseases. Our results are crucial for understanding the pathogenesis and investigating the treatment of these diseases.

Secular trends and features of thalamic hemorrhages compared with other hypertensive intracerebral hemorrhages: an 18-year single-center retrospective assessment

Introduction

Trends regarding the locations of hypertensive cerebral hemorrhages are unclear. To clarify hypertensive hemorrhage trends, we investigated intracerebral hemorrhages (ICHs) over an 18-year period, focusing on thalamic hemorrhages compared with other sites of hemorrhages.

Methods

We reviewed the cases of patients hospitalized for hypertensive ICH in 2004-2021 at our hospital; 1,320 eligible patients were registered with a primary ICH/intraventricular hemorrhage. After exclusion criteria were applied, we retrospectively analyzed 1,026 hypertensive ICH cases.

Results

The proportions of thalamic and subcortical hemorrhages increased over the 18-year period, whereas putaminal hemorrhage decreased. Multivariate logistic regression analyses revealed that for thalamic hemorrhage, ≥200 mmHg systolic blood pressure (p = 0.031), bleeding <15 mL (p = 0.001), and higher modified Rankin scale (mRS) score ≥ 4 at discharge (p = 0.006) were significant variables in the late period (2013-2021) versus the early period (2004-2012), whereas for putaminal hemorrhage, significant factors in the late period were triglyceride <150 mg/dL (p = 0.006) and mRS score ≥ 4 at discharge (p = 0.002). Among the features of the thalamic hemorrhages in the late period revealed by our group comparison with the putaminal and subcortical hemorrhages, the total and subcortical microbleeds were more notable in the thalamic hemorrhages than in the other two types of hemorrhage, whereas cerebellar microbleeds were more prominent when compared only with subcortical hemorrhages.

Discussion

Our findings revealed an increasing trend for thalamic hypertensive hemorrhage and a decreasing trend for putaminal hemorrhage. The thalamic hemorrhage increase was observed in both young and older patients, regardless of gender. The main features of thalamic hemorrhage in the late period versus the early period were decrease in larger hemorrhage (≥15 mL) and an increase in cases with higher systolic blood pressure (at least partially involved a small number of untreated hypertensive patients who developed major bleeding). The total and subcortical microbleeds were more notable in the thalamic hemorrhages of the late period than in the putaminal and subcortical hemorrhages. These results may contribute to a better understanding of the recent trends of hypertensive ICHs and may help guide their appropriate treatments for this condition.