ISSN:0899-3459    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Recent advances in magnetic resonance imaging (MRI) technology has allowed the development of imaging sequences tailored to the assessment of exquisite anatomic detail of the temporal bone structures. This article describes MRI of the normal temporal bone anatomy, with emphasis on common anatomic variants and clinically relevant structures.

ISSN:0899-3459    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

During the past 20 years, there have been significant advances in cochlear implants as the treatment of choice for profoundly hearing-impaired children. The increasing application of cochlear implant has brought with it an increase in the investigational use of computed tomography and magnetic resonance imaging. In this article, the author reviews (a) the anatomy and embryology of the inner ear, (b) the pathological changes associated with congenital sensorineural hearing loss (SNHL), and (c) the spectrum of imaging findings in patients with SNHL.

ISSN:0899-3459    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The auditory (cochlear) labyrinth, the cochlea, holds the hearing sensory receptors. The vestibular labyrinth contains the sensory receptors for balance, which lie in the three semicircular canals and in the otolithic organs (the saccule and utricle). Pure tone audiometry and brain stem evoked audiometry can help to differentiate a peripheral cochlear disorder from central lesion. The type of nystagmus, severity of postural instability, and neurological evaluation can help to differentiate a peripheral vestibular disorder from a central vestibular lesion. The decision whether to perform an appropriate imaging such as brain imaging versus labyrinthine imaging depends on the clinical and paraclinical information provided to the radiologist by the neurotologist, neurologist, or other clinicians. The magnetic resonance imaging characteristics of peripheral cochlear and vestibular lesions are the main focus of this article.

ISSN:0899-3459    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Imaging of the facial nerve has proved its usefulness to physicians in the evaluation of pathological conditions of this nerve. Magnetic resonance imaging (MRI) of the facial nerve should always be obtained selectively and should include the parotid gland in case of peripheral facial nerve palsy. Gadolinium-DTPA contrast pulse sequence is the most informative MRI study for evaluation of facial nerve pathology. This article reviews the imaging anatomy of the facial nerve and describes the clinical features and MR characteristics of common disorders of the facial nerve.

ISSN:0899-3459    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Magnetic resonance imaging (MRI) is presently the study of choice for assessment of the internal auditory canal (IAC). MRI provides excellent assessment of the IAC and the bony changes occurring in the canal walls, and it provides excellent demonstration of the content of the canal. Pathological processes arising within the IAC are well visualized by various MR sequences. The possibility of demonstrating masses as small as 2 mm has propelled MRI into the leading role for diagnosis of vestibular schwannoma. Unfortunately, the high cost of MR has been a limiting factor in its use as a screening test for patients with sensorineural hearing loss (SNHL) of unknown origin. Auditory brain stem response has been widely used as a screening procedure, but this test fails to recognize small lesions and cannot be used whenever hearing loss is severe. In this article, we will discuss our approach to assessment of the IAC in patients with retrocochlear SNHL or vestibular symptoms of central origin, review the pathological processes involving the IAC walls or arising within the canal, emphasizing the appropriate MRI sequences used for diagnosis.

ISSN:0899-3459    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Langerhans cell histiocytosis (LCH) may involve nearly every organ of the body. In children, head and neck involvement has been reported in as many as 82% of patients. Sites of head and neck involvement include skull, temporal bone, orbit, mandible, maxilla and cervical nodes. In addition, patients may have coexisting central nervous system (CNS) involvement adjacent to, or remote from, osseous lesions. Magnetic resonance imaging (MRI) of the temporal bone in patients with LCH is ideal for evaluating the extracranial extent of the soft-tissue mass and is complementary to computed tomography (CT) in the assessment of osseous erosion. MRI is superb in the evaluation of intracranial extension, usually into the middle cranial fossa, and of patency of adjacent vascular structures. It is the imaging modality of choice to evaluate patients with suspected CNS involvement of LCH, which includes lesions of the infundibulum, cerebrum, cerebellum, and extra-axial spaces.

ISSN:0899-3459    

出版商:OVID    

年代:2000

数据来源: OVID