摘要:

MRI has made a remarkable impact upon diagnostic evaluation of the temporal hone and its diseases. Although high resolution CT is preferable for study of common maladies of the middle ear and optic capsule, MRI is currently the study of choice for evaluation of the internal auditory canal, cerebellopontine angle, and hrainstem. MRI is also very useful in evaluations of complications of chronic otitis media. This manuscript is divided into sections on inflammatory disease, internal auditory canal/cerebellopontine angle, vascular compartments, facial nerve, and trauma. In addition, several miscellaneous entities are discussed.

ISSN:0899-3459    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

MR plays an important role in evaluating pathologic conditions that affect the orbit. MR appears to be superior to ultrasound and computed tomography in evaluation of intraocular tumors and fluid collections. In evaluation of noncalcilied intraorhital tumors, MR can provide more information regarding orbital apex involvement and intracranial extension. Inflammatory lesions, particularly orbital pseudotumor, can be differentiated from metastatic disease based on differences in signal intensity providing greater specificity than CT. Specific prognostic information may be obtained regarding potentially treatable cases of Graves' disease. Using MR, vascular lesions of the orbit can be assessed for patency or thrombosis without use of intravenous contrast. Demonstration of secondary extension by para-orbital sinus tumors by MR is often helpful in evaluating involvement of the soft tissue structures of the orbit. Potential applications in evaluation of orbital trauma include characterization of orbital hematomas and orbital blow-out fractures.

ISSN:0899-3459    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

MRI has been very helpful in evaluating tumors in the paranasal sinuses. MRI can differentiate retained secretions from tumors. The multiplanar capabilities of MRI are also very helpful in identifying tumor margins. Although a specific diagnosis can he suggested in most cases, demonstration of the extent of the disease and specifically the relationship to key surgical landmarks is more important. Structures of thin cortical bone are better seen with CT than MRI. For several reasons, CT is still the examination of choice for evaluation of the osteomeatal complex and inflammatory disease of the sinuses.

ISSN:0899-3459    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Imaging of the upper acrodigestive tract, mainly the nasopharynx and oropharynx, has always challenged the radiologist. It is clear (hat MRI has a leading role in the diagnosis and treatment planning of patients with diseases of the head and neck. This is especially true in the nasopharynx. Although improvements have been made in x-ray diagnosis through the years, subtle diagnoses have been difficult to make because of the variations in airway contour and the superimposition of areas of interest. CT allowed the deep soft tissue planes to he evaluated and provides a complement to the physical examination of the nasopharynx, oral pharynx, and skull base. MRI possesses many advantages over other imaging modalities. The ability to differentiate between inflammatory and neoplastic diseases is extremely important for tumor staging and patient management. At the present time it is not possible to predict the histology of a nasopharyngeal tumor, but the ability to differentiate between various histologic types would be of obvious importance. More experience is needed before this bridge can be crossed.

ISSN:0899-3459    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

In general. MRI produces superior soft tissue detail in evaluating the tongue and oropharynx lhan does CT. MRI is therefore considered the study of choice in this area. Lack of artifact from dental amalgam and beam hardening artifact from the mandible on MRI also eliminates two major shortcomings of CT in the examination of this area. Finally, the ability of MRI to obtain direct coronal and sagittal scan planes is a distinct advantage in recognizing intrinsic tongue musculature and assessing tumor volume and spread for treatment planning.

ISSN:0899-3459    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The development of appropriate surface coils has resulted in outstanding depiction of the laryngeal anatomy using MRI. The multiplanar capability of MR allows superior definition of anatomy and tumor extent compared with CT scanning. MR appears to he more effective in detecting cartilage invasion. MR is as effective as CT in defining adenopathy and extension into the carotid sheath. MRI is therefore the primary modality in imaging the larynx.

ISSN:0899-3459    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Detecting cervical adenopathy is critical in the management of carcinomas in head and neck. CT scanning remains a very effective modality in defining adenopathy. TI-weighted MRI scans are comparable to CT in detecting lymph nodes. T2-weighted images are less useful as the lymph nodes tend to have long T2 relaxation times similar to the surrounding fat. MR has not proved to be useful in detecting carcinoma in non-enlarged cervical nodes. The morphologic criteria developed for metastatic nodes with CT are appropriate with MRI (size, shape, signal, extracapsular spread). Gadolinium is sometimes useful in defining central necrosis in metastatic squamous cell adenopathy.

ISSN:0899-3459    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Interventional MRI is clearly in its early stages of development. While the value of MR-guided aspiration cytology and MR evaluation of deep electrode implantation in the brain has already been confirmed with human clinical studies, the future of MR-guided interstitial laser therapy remains to be proven. Despite this, as we look ahead into the 1990s and the millennium, it is possible to imagine dedicated MR laser therapy units for combined radiological and surgical outpatient approaches in what may become the operating rooms of the 21st century.

ISSN:0899-3459    

出版商:OVID    

年代:1990

数据来源: OVID

ISSN:0899-3459    

出版商:OVID    

年代:1990

数据来源: OVID

ISSN:0899-3459    

出版商:OVID    

年代:1990

数据来源: OVID