Pictorial review: Extracranial enhancement on black-blood brain MRI

3D contrast-enhanced T1W black-blood imaging has become the standard for vessel wall imaging in vasculitis and shows high sensitivity for detecting brain and meningeal lesions. While primarily designed for intracranial assessment, 3D black-blood's high anatomical detail and high contrast-to-noise ratio also facilitates extracranial pathology detection on brain MRI. This pictorial review highlights the added diagnostic value of 3D contrast-enhanced black-blood MRI beyond the intracranial compartment. The first section reviews key technical principles of black-blood imaging, including sequence design, contrast mechanisms, and comparison with conventional contrast-enhanced T1W techniques. The second section outlines expected and unexpected extracranial findings detectable with this technique. The final section illustrates these concepts through representative cases. Particular attention is given to orbital pathology (optic neuropathies, thyroid eye disease, tumors), ear-nose-throat disorders (mastoiditis, sinusitis, salivary gland disease, perineural tumor spread), and musculoskeletal abnormalities of the head and neck (synovitis and subtle bone marrow changes relevant for inflammatory diseases and bone metastases). The review concludes by encouraging broader use of 3D contrast-enhanced black-blood MRI in clinical brain protocols, as the technique allows detection of relevant extracranial pathology in addition to its established intracranial applications.