Radiologic appearance of chronic parapharyngeal Teflon granuloma.

Although Teflon has been used for almost 5 decades to provide tissue augmentation in various surgical indications, including head and neck surgery, its use has significantly declined in the last 2 decades, primarily because of its implication in granuloma formation. Teflon granulomas have been shown to cause false positives on positron emission tomography imaging and have been reported to have a characteristic magnetic resonance imaging (MRI) appearance. We report a patient with a large chronic Teflon granuloma of the parapharyngeal space that caused significant bony erosion of the atlas vertebra. The lesion's MRI signal characteristics were indistinguishable from those of surrounding tissues, while it showed characteristic hyperdensity on computed tomography due to the presence of fluorine atoms within Teflon. As MRI may supersede or replace computed tomography for a number of indications, and as Teflon has been used in large numbers of patients whose records may not always be available, knowledge of these findings has clinical relevance.

Culture-Negative intracerebral abscesses in children and adolescents from Streptococcus anginosus group infection: a case series.

We report the use of 16S ribosomal RNA gene amplification and sequencing to diagnose culture-negative intracerebral abscesses in younger patients. These 3 cases demonstrate the optimal application of gene sequencing from direct specimens for patients with negative culture results compromised by antibacterial therapy but histories highly suggestive of acute bacterial infection.

Magnetic resonance imaging of the orbit.

Magnetic resonance imaging (MRI) employs the nuclear resonance phenomenon to produce images of living tissues. Unlike computed tomography (CT), which relies solely on differences in the propensity of tissues to absorb X-rays to produce various contrasts, MRI offers a wide variety of pulse sequences, each of which exploits differences in the magnetic properties of protons in living tissue to produce contrast resolution. When optimal protocols are used, MRI contrast resolution in the orbital soft tissues is superior to that provided by any other imaging modality. Other advantages of MRI over CT include the ability to select the plane of imaging, and improved safety due to the lack of ionizing radiation.

Interventional neuroradiology for the ophthalmologist.

The past two decades have witnessed major advances in diagnosing vascular conditions that affect blood supply and hemorrhagic risk to the brain and the eye. Technological improvements have resulted in the ability to better radiologically image the cerebrovascular system and to deliver pharmacological and embolic agents that have high specificity. Neuroradiological interventional therapy has become the preferred option in managing many conditions that were previously treated by standard neurosurgical procedures. Some of these conditions were considered either inoperable or treatable only with unacceptable neurosurgical risks. This article reviews the current state of the neuroradiological interventional management in conditions that may be encountered in ophthalmological practice.

Orbital rhabdomyosarcoma and simulating lesions.

The appropriate diagnosis and treatment of orbital rhabdomyosarcoma requires close cooperation and communication between the radiologist, the ophthalmologist, and the medical and radiation oncologists. The clinical presentation, imaging characteristics, and staging of orbital rhabdomyosarcoma are discussed. A discussion of several important simulating lesions and their distinguishing characteristics follows.

Glossopharyngeal schwannoma of the suprahyoid carotid space: case report and discussion of the relationship to the carotid artery.

BACKGROUND: The distinction between lesions of the deep parotid space and those of the carotid space has been greatly facilitated by cross-sectional imaging, particularly magnetic resonance imaging (MRI), due to 1) good assessment of parapharyngeal fat displacement, and 2) reliable and consistent identification of the carotid artery. While masticator space masses consistently displace the carotid artery posteriorly, it is generally assumed that carotid space masses, particularly schwannomas, displace the carotid artery anteriorly. We report on a patient with a rare glossopharyngeal schwannoma of the carotid space that caused posterior displacement of the carotid artery. METHODS: A 38-year-old female presented with headaches and a pharyngeal sensation of a foreign body without dysgeusia and dysphagia. Computed tomography (CT) and MRI showed a left carotid space mass, suggestive of a schwannoma, although the internal carotid artery was displaced posteriorly. The mass was hypovascular at angiography. The patient underwent surgical excision of her lesion via a left cervical-parotid approach. RESULTS: In our patient with a carotid space mass, all imaging features suggested a schwannoma, except for posterior displacement of the carotid artery. A glossopharyngeal nerve schwannoma was found at surgery. Schwannomas of the glossopharyngeal nerve are uncommon, and those originating from the extracranial course of the nerve are extremely rare. CONCLUSIONS: Schwannomas of the suprahyoid carotid space most commonly arise from the vagus nerve and have a typical pattern, which includes anterior displacement of the carotid artery. A rare exception to this has been reported in schwannomas of the sympathetic nerve, which may displace the carotid artery posteromedially. Our patient had a schwannoma of the extracranial glossopharyngeal nerve, which caused posterolateral carotid displacement.