Early Clues, critical outcomes: a pictorial review of subtle intracranial pathologies on non-contrast head CT

Non-contrast head CT (NCHCT) remains the first-line imaging modality for acute neurologic presentations, but subtle yet critical pathologies can be missed due to its inherent technical limitations. This pictorial review provides a systematic, anatomy-based framework covering all major anatomical compartments visible on emergency NCHCT, serving as a practical educational guide for radiology residents and emergency physicians. The review summarizes key imaging patterns, relevant clinical contexts, and technical optimization methods that aid in detecting subtle intracranial pathologies across anatomical regions. The anatomical areas covered are: Intra-axial: Cerebral hemispheres, deep gray nuclei, brainstem, cerebellum, and the periventricular region. Extra-axial: Subdural, subarachnoid, and meningeal abnormalities, including cranial nerve pathologies. Vascular structures, sellar/parasellar regions, osseous structures, and extracranial soft tissues. A disciplined, systematic interpretation that extends beyond the brain parenchyma to all visible structures, combined with technical optimization and clinical correlation, is crucial for minimizing diagnostic errors and improving patient outcomes.