Seminars in Ultrasound Ct and Mri最新文献

Dizziness and vertigo, a prevalent and often debilitating symptom, can be attributed to various lesions involving the inner ear and cerebellopontine angle. Diagnostic imaging, especially magnetic resonance imaging, is crucial in diagnosing and differentiating these conditions. This article provides a comprehensive overview of imaging characteristics related to common causes of dizziness and vertigo, including labyrinthitis, vestibular neuritis, and tumors. It highlights distinguishing between these conditions to ensure accurate diagnosis and appropriate management.

Ménière's disease (MD) is a chronic disorder of the inner ear characterized by vertigo, hearing loss, tinnitus, and aural fullness. The pathophysiology of MD involves endolymphatic hydrops, an abnormal accumulation of endolymph fluid, although the exact cause remains unclear, potentially involving genetic, environmental, and autoimmune factors. Recent advancements in magnetic resonance imaging have significantly enhanced diagnostic capabilities. This technique uses gadolinium-based contrast agents to differentiate between endolymph and perilymph. Imaging techniques such as 3-dimensional fluid-attenuated inversion recovery and 3-dimensional-real-inversion recovery sequences are used to classify endolymphatic hydrops into grades based on the severity of dilation in the cochlea and vestibule. The degree of perilymphatic enhancement, indicative of blood-labyrinthine barrier breakdown, further aids in diagnosing MD. Accurate diagnosis relies on distinguishing between perilymphatic and endolymphatic enhancement patterns and recognizing mimicking conditions.

Dizziness and vertigo are common complaints in both emergency and outpatient settings, requiring careful evaluation to determine appropriate diagnosis and treatment. Differentiating between peripheral and central causes of dizziness is crucial for effective management. Peripheral causes, such as vestibular neuritis, benign paroxysmal positional vertigo, and Ménière's disease, are contrasted with central causes such as stroke, demyelinating diseases, and posterior fossa tumors. Diagnostic approaches include assessing nystagmus patterns, the vestibulo-ocular reflex, and the HINTS Plus test. Vestibular disorders are classified as acute, episodic, or chronic based on duration and symptom presentation. Imaging plays a significant role in identifying central causes when clinical findings are inconclusive. This paper provides a comprehensive overview of the clinical evaluation and diagnostic methods for dizziness and vertigo, with emphasis on distinguishing peripheral from central etiologies.

The broad differential diagnosis of vertigo and dizziness passes through peripheral and central causes. Peripheral vestibular disorders, such as Ménière's disease and benign paroxysmal positional vertigo, are commonly diagnosed clinically, with imaging serving to exclude other conditions. Temporal bone trauma, cholesteatoma, third window syndrome, otospongiosis, jugular bulb variants, and temporomandibular disorders are identified as significant causes of dizziness and vertigo, each with specific diagnostic and management considerations. Advanced imaging techniques, including high-resolution computed tomography and magnetic resonance imaging, play crucial roles in diagnosing and differentiating these conditions. The management strategies vary depending on the underlying cause and often involve surgical or medical interventions tailored to the specific pathology.

Dizziness and vertigo, frequently associated with cerebrovascular origins, pose a substantial challenge in emergency medical settings due to their potential to be associated with severe underlying conditions. Sudden-onset dizziness, in particular, may be an early indicator of critical events such as stroke or transient ischemic attack. This comprehensive review encompasses the differential diagnosis of central causes of dizziness and vertigo, emphasizing the crucial role of imaging modalities in the accurate detection and assessment, including cerebrovascular diseases, inflammatory disorders, infections, and other conditions such as vestibular migraine and cervical spondylosis. It highlights the significance of advanced imaging techniques, particularly magnetic resonance imaging and computed tomography in identifying and distinguishing these conditions.

The intricate anatomy and embryology of the middle ear, labyrinth, and vertigo-related intracranial pathways involve complex developmental processes and contributions from multiple germ layers. The middle ear, comprised of the tympanic cavity, ossicles, and Eustachian tube, develops from the first and second branchial arches and clefts. In contrast, the inner ear originates from the otic vesicle, forming the bony and membranous labyrinths. The embryological timeline spans from the 40th day of gestation to the 24th week. The vestibulocochlear nerve (VIII cranial nerve) emerges with the inner ear structures and is essential for auditory and vestibular functions. The brainstem integrates sensory inputs from the labyrinth through various nuclei and pathways, contributing to balance and spatial awareness. This review highlights the critical developmental stages and anatomical details relevant to understanding auditory and vestibular system disorders.