Central Nervous System Infections, Abscesses, and Inflammatory Demylinating Disorders — WACS Viva & Clinical Scenarios (Neuroradiology and Head and Neck Imaging)

Exam-style central nervous system infections, abscesses, and inflammatory demylinating disorders viva scenarios with examiner probes and model answers for…

Scenarios covered

• SCENARIO 1: A 34-year-old human immunodeficiency virus-positive patient presents with progressive headache, fever, focal neurological deficits, and altered sensorium. Magnetic resonance imaging demonstrates multiple rim-enhancing subcortical basal ganglia and corticomedullary junction lesions with surrounding vasogenic oedema. Discuss the imaging differential diagnosis, key multi-parametric MRI discriminating features between cerebral toxoplasmosis and primary central nervous system lymphoma, and the anticipated post-treatment imaging findings.
• SCENARIO 2: A 28-year-old female presents with subacute headache, low-grade fever, cranial nerve palsies (CN III and VI), and neck stiffness. Contrast-enhanced brain CT and MRI show thick, gelatinous leptomeningeal enhancement in the basal cisterns, sylvian fissures, and ambient cisterns, associated with communicating hydrocephalus and bilateral acute lacunar infarcts in the medial lenticulostriate territory. Detail the classical imaging hallmarks of tuberculous meningitis, the pathophysiology and vascular distribution of associated vasculitic infarctions, and secondary intracranial complications.
• SCENARIO 3: An 18-year-old male with chronic suppurative otitis media presents with worsening left-sided headache, lethargy, fever, and papilloedema. Contrast-enhanced MRI reveals a well-defined cystic mass with a thin, smooth, T2-hypointense peripheral rim showing intense rim enhancement in the left temporal lobe, accompanied by restricted diffusion centrally on DWI/ADC, marked surrounding vasogenic oedema, and ipsilateral transverse-sigmoid sinus thrombosis. Describe the evolutionary stages of pyogenic brain abscess formation, the imaging physics behind diffusion restriction within the cavity, the dual-
• SCENARIO 4: A 26-year-old female presents with acute visual loss secondary to unilateral optic neuritis followed six months later by acute paraparesis and sensory ataxia. Spinal MRI demonstrates a continuous hyperintense T2 lesion spanning four vertebral segments with cord expansion, while brain MRI shows non-specific periventricular lesions. Contrast the clinical, radiological, and immunopathological criteria differentiating Multiple Sclerosis (utilizing McDonald diagnostic imaging criteria) from Neuromyelitis Optica Spectrum Disorder (NMOSD) and Myelin Oligodendrocyte Glycoprotein Antibody-Associated Di
• SCENARIO 5: A 42-year-old male presents with adult-onset focal motor seizures. Computed tomography and high-resolution 3D T2-weighted MRI (CISS/FIESTA) demonstrate multiple intracranial cystic parenchymal lesions at various evolutionary stages, some showing a central eccentric mural nodule and others displaying dense punctate calcifications. Explain the imaging staging of neurocysticercosis, describe the pathognomonic radiological signs across each stage, and outline the multi-sequence protocol optimized for scolex and intraventricular lesion identification.