Iodine-stained fragmented thromboembolism.

AIM: Iodine-stained fragmented thromboembolism (ISFT) is a rare phenomenon encountered in the immediate aftermath of mechanical thrombectomy or rarely as a complication of post-carotid stenting. The aim was to describe the imaging appearance and discuss its pathophysiology. METHOD: This is a retrospective review of patients who underwent mechanical thrombectomy for acute stroke at a single institution over the period of one year. All patients underwent the standard acute stroke imaging protocol (CT head, CT angiogram (CTA) and CT brain perfusion) and when clinically appropriate followed by catheter angiogram and mechanical thrombectomy. ISFT was defined as an arterial luminal filling defect with Hounsfield density equal to or greater than iodine seen on the biplanar CT or conventional CT. The presence and location of ISFT were documented. Standard CT angiogram (CTA) or magnetic resonance angiogram (MRA) was performed 24-48 hours after the neurointerventional procedure to assess for recanalization, volume of infarction and the fate of the ISFT. RESULTS: ISFTs were identified in eight (five males and three females, age range 18-80 years) out of 49 patients in the following locations: distal M1 (n = 1), M2 (n = 4), M3 (n = 1), A1 (n = 1), distal A2 (n = 1). ISFT and vessel recanalization occurred in five patients on follow-up. ISFT and vessel occlusion persisted in two patients. CONCLUSION: ISFT is likely the result of mechanical disruption of a thromboembolus, and porosity of the thromboembolus fragment may transiently retain iodinated contrast. Recognition of this entity may be important to aid detection of residual thromboembolism and avoid misinterpretation as calcified thromboembolism.

High resolution magnetic resonance imaging for exposing facial nerve zonal vulnerability to microbleeds: A rare cause of facial palsy.

Background We report a case of hypertensive microbleeds strategically located at the attached segment (AS) and root entry zone (REZ) at the left facial nerve causing facial paralysis. Case Report A 60-year-old woman presented with sudden onset left facial paralysis. Medical history was significant for poorly controlled hypertension secondary to bilateral adrenal hyperplasia (primary hyperaldosteronism). The patient was initially treated for presumptive Bell's palsy. Subsequent magnetic resonance imaging of the brain and internal auditory canal showed two microbleeds at the left cerebellopontine angle. Dedicated coronal T1 magnetization prepared rapid acquisition gradient echo and T2 sampling perfection with application optimized contrasts using different flip angle evolution sequences revealed two acute microbleeds located at the attached AS and REZ of the left facial nerve. The patient experienced only partial recovery from House-Brackmann grade IV facial paralysis at presentation to a House-Brackmann grade III facial paralysis at 1 year of follow up. Conclusions To the best of the authors' knowledge, this is the first reported case of facial paralysis caused by microbleeds directly affecting the vulnerable AS and REZ facial nerve segments. We discuss the zonal microanatomy of the facial nerve and the crucial role of high resolution MRI for diagnosis.

Susceptibility weighted imaging in acute cerebral ischemia: review of emerging technical concepts and clinical applications.

Susceptibility weighted imaging (SWI) is an essential magnetic resonance imaging sequence in the assessment of acute ischemic stroke. In this article, we discuss the physics principals and clinical application of conventional SWI and multi-echo SWI sequences. We review the research evidence and practical approach of SWI in acute ischemic stroke by focusing on the detection and characterization of thromboembolism in the cerebral circulation. In addition, we discuss the role of SWI in the assessment of neuroparenchyma by depiction of asymmetric hypointense cortical veins in the ischemic territory (surrogate tissue perfusion), detection of existing microbleeds before stroke treatment and monitoring for hemorrhagic transformation post-treatment. In conclusion, the SWI sequence complements other parameters in the stroke magnetic resonance imaging protocol and understanding of the research evidence is vital for practising stroke neurologists and neuroradiologists.

Serial magnetic resonance imaging findings of intracerebral spread of listeria utilising subcortical U-fibres and the extreme capsule.

We present a case of Listeria monocytogenes cerebral abscess with axonal spread via the subcortical U-fibres and extreme capsule on magnetic resonance imaging, with follow-up studies demonstrating serial reduction in oedema and enhancement pattern of the white-matter fibre tracts following antimicrobial treatment. We discuss the microbiological mechanism of bacterial mobility to account for these unique imaging features. Recognition of this distinct pattern of spread of L. monocytogenes cerebral abscess may aid in diagnosis and enable early microbiological culture and treatment.

Duplication of the superficial femoral artery: comprehensive review of imaging literature and insight into embryology.

An extremely rare case of duplicated superficial femoral artery (SFA) was incidentally observed on computed tomography angiogram (CTA) of the lower limbs for presurgical planning for an osteomyocutaneous fibula flap in a patient with T4a oropharyngeal squamous cell carcinoma (SCC). To our knowledge, this is the sixth reported case in the imaging literature. We performed a comprehensive review of the English literature and discuss the underlying embryological origin underpinning this rare anatomical variant.