Acute optic nerve infarction demonstrated by diffusion-weighted imaging in a case of rhinocerebral mucormycosis.

SUMMARY: A 60-year-old woman developed right-eye vision loss secondary to rhinocerebral mucormycosis. Routine MR imaging sequences including enhanced MR imaging showed normal optic nerves, but a diffusion-weighted sequence and apparent diffusion coefficient maps revealed markedly restricted diffusion in the right optic nerve. This MR imaging abnormality of optic nerve infarction due to mucormycosis has not been reported previously.

Texture-Based Analysis of 100 MR Examinations of Head and Neck Tumors - Is It Possible to Discriminate Between Benign and Malignant Masses in a Multicenter Trial?

AIM: To evaluate whether texture-based analysis of standard MRI sequences can help in the discrimination between benign and malignant head and neck tumors. MATERIALS AND METHODS: The MR images of 100 patients with a histologically clarified head or neck mass, from two different institutions, were analyzed. Texture-based analysis was performed using texture analysis software, with region of interest measurements for 2 D and 3 D evaluation independently for all axial sequences. COC, RUN, GRA, ARM, and WAV features were calculated for all ROIs. 10 texture feature subsets were used for a linear discriminant analysis, in combination with k-nearest-neighbor classification. Benign and malignant tumors were compared with regard to texture-based values. RESULTS: There were differences in the images from different field-strength scanners, as well as from different vendors. For the differentiation of benign and malignant tumors, we found differences on STIR and T2-weighted images for 2 D, and on contrast-enhanced T1-TSE with fat saturation for 3 D evaluation. In a separate analysis of the subgroups 1.5 and 3 Tesla, more discriminating features were found. CONCLUSION: Texture-based analysis is a useful tool in the discrimination of benign and malignant tumors when performed on one scanner with the same protocol. We cannot recommend this technique for the use of multicenter studies with clinical data. KEY POINTS: 2 D/3 D texture-based analysis can be performed in head and neck tumors. Texture-based analysis can differentiate between benign and malignant masses. Analyzed MR images should originate from one scanner with an identical protocol.

Intratympanic Contrast in the Evaluation of Menière Disease: Understanding the Limits.

BACKGROUND AND PURPOSE: Studies describing endolymphatic hydrops in Menière disease after off-label intratympanic gadolinium-based contrast have been limited by long acquisition times. We aimed to demonstrate the feasibility of post-intratympanic imaging on a 3T MR imaging system within a clinically tolerable acquisition time and to address potential pitfalls in acquisition or interpretation. MATERIALS AND METHODS: FDA Investigational New Drug 115,342 and institutional review board approval were obtained for intratympanic injection of 8-fold diluted Gd-DTPA into the more symptomatic ear of 6 adults with Menière disease. 3T MR imaging was performed using a 3-inch surface coil before and up to 28 hours after injection using FLAIR to define the nonenhancing endolymphatic space within the enhancing perilymph. Variable FLAIR TI images were used to determine the impact of fluid-suppression on interpretation. Image quality was assessed for perilymphatic and extralabyrinthine contrast enhancement, definition of endolymphatic anatomy, and other anatomic variants or pathologic findings. RESULTS: The surface coil afforded 0.375 × 0.375 mm in-plane FLAIR resolution in <4 minutes 30 seconds, sufficient to perceive the nonenhancing spiral lamina, interscalar septa, and endolymphatic structures. Coronal views highlighted a potential interpretation pitfall of vestibular endolymphatic distention overestimation due to partial volume averaging. Varying FLAIR TI resulted in visible changes in the perception of the cochlear endolymphatic space. CSF enhancement was detectable at the internal auditory canal fundus on the injected side in half of the patients, which may confound interpretation. CONCLUSIONS: Using a surface coil preserves high resolution within a clinically acceptable acquisition time. Pitfalls remain regarding the interpretation of these images and optimizing protocols across platforms in the absence of a clear internal reference for standardization.

Successful use of nasal-CPAP for obstructive sleep apnea in Hunter syndrome with diffuse airway involvement.

A patient with Hunter syndrome and diffuse airway obstruction had daytime hypersomnolence, snoring, and alveolar hypoventilation. Polysomnography showed severe obstructive sleep apnea. In the past, all reported cases of sleep apnea in patients with mucopolysaccharidoses had been treated with tonsillectomy/adenoidectomy or tracheostomy. This patient, in whom tracheostomy would have been very difficult due to the diffuse nature of his airway involvement, was successfully treated with high pressure nasal CPAP and supplemental oxygen.

Familial trigeminal anesthesia.

Familial congenital trigeminal anesthesia as an isolated abnormality is an unusual disorder. To our knowledge, only one family has previously been reported. We report here a family with three affected members demonstrating facial anesthesia, bilateral corneal changes, and nasal septal damage secondary to self-traumatization. Magnetic resonance imaging demonstrated hypoplasia of gasserian ganglia and trigeminal nerves in the affected father of two affected sons. The pathogenesis of this disorder appears to be congenital hypoplasia of the trigeminal nerves and gasserian ganglia that is inherited in a dominant fashion.

Magnetic resonance imaging of pituitary stalk hypoplasia. A discrete midline anomaly associated with endocrine abnormalities in septo-optic dysplasia.

Septo-optic dysplasia describes optic nerve hypoplasia in association with endocrine disturbances and/or midline brain malformations. Magnetic resonance imaging of the brain was used to study two patients with optic nerve hypoplasia, endocrine abnormalities, and normal midline brain anatomy on prior computed tomographic scan. The magnetic resonance imaging scans showed normal midline brain anatomy except for failure to visualize the pituitary stalk, a structure that magnetic resonance imaging has shown to be 100% sensitive in imaging in our normal controls. We propose that our two patients have endocrine abnormalities due to the discrete anomaly of pituitary stalk hypoplasia.

Magnetic resonance imaging and intraocular foreign bodies.

We conducted in vitro and in vivo experiments to study magnetic resonance imaging of intraocular foreign bodies. Diamagnetic and paramagnetic foreign bodies were imaged without artifact and without movement during the imaging process, while ferromagnetic foreign bodies produced large amounts of artifact that prevented meaningful images. All fetromagnetic foreign bodies moved during in vitro imaging. During in vivo imaging, three of four ferromagnetic bodies moved, producing substantial retinal injury. We concluded that magnetic resonance imaging is contraindicated in traumatized eyes with suspected ferromagnetic foreign bodies.

Diagnosis of carotid body tumors by dynamic computerized tomography.

The carotid body tumor, although uncommon, is frequently considered in the differential diagnosis of cervical masses. When this lesion becomes a serious diagnostic possibility, angiography must be considered. Currently angiography is the only nonsurgical modality that can reliably confirm the clinical diagnosis. We describe the case of a patient in whom a carotid body tumor was diagnosed preoperatively by dynamic computerized tomography. Dynamic computerized tomography, a relatively noninvasive technique, should now be deemed the technique of choice for diagnosis of carotid body tumors, thus avoiding the potential morbidity of angiography. In patients for whom tumor removal is indicated, however, preoperative angiography is still mandatory in order to plan the best operative procedure.

Bilateral orbital emphysema from compressed air injury.

PURPOSE: To describe a patient who developed bilateral subconjunctival and orbital emphysema after an automobile tire explosion. METHOD: Case report. RESULTS: A 60-year-old man sustained bilateral ocular injury after a tire explosion. Ophthalmic examination disclosed bilateral subconjunctival air, with no visible conjunctival laceration. Computed tomography showed orbital emphysema, with no evidence of orbital fracture. Follow-up examination 2 weeks after the injury disclosed resolution of the subconjunctival air. Best-corrected visual acuity in the right eye was decreased after the explosion but improved to the baseline level of 20/40 2 weeks after the injury. CONCLUSION: Subconjunctival and orbital emphysema can occur from high-pressure air injury in the absence of an obvious entry site.

Orbital and optic pathway sarcoidosis: MR findings.

PURPOSE: To identify and characterize the MR findings of sarcoidosis when it involves the orbit and visual pathways. METHODS: The MR scans of 15 patients, 3 with presumed and 12 with proved orbital or optic pathway sarcoidosis were retrospectively reviewed. RESULTS: Eight patients had MR evidence of optic nerve involvement by sarcoid granuloma. Perineural enhancement was seen in four cases, optic atrophy in one. Three who had had unenhanced scans showed optic nerve enlargement. Nine patients had optic chiasmal involvement. One patient had increased T2 signal in the optic radiations. Three patients had orbital masses that had MR signal characteristics similar to pseudotumor. Five patients had periventricular white matter abnormalities closely resembling multiple sclerosis. CONCLUSIONS: Sarcoidosis should be considered in the differential diagnosis of optic nerve or nerve sheath enhancement on MR. Orbital sarcoidosis has MR characteristics very similar to pseudotumor.

Encephalopathy in AIDS patients: evaluation with MR imaging.

The presence and extent of encephalopathy were evaluated in 47 patients with AIDS or AIDS-related complex (ARC) by the use of MR imaging. Twenty-nine (62%) of the patients showed some form of white matter disease, exhibited as high signal intensity on T2-weighted images. Focal white matter lesions were seen in 23 (49%) of the patients, while a diffuse white matter process was observed in six patients (13%). Of the 29 patients who had white matter disease on MR scans, 17 (36%) had a suggestion of white matter involvement on an initial CT study. Meanwhile, 12 (26%) of the patients had a normal CT scan on the initial examination. MR findings showed predominant disease in the subinsular and peritrigonal white matter areas. Marked cerebral atrophy was observed in 17 (36%) of 47 patients, cerebellar atrophy in 18 (38%), and brainstem atrophy in seven patients (15%). Pathologic findings showed that toxoplasmosis was present in eight patients (17%), and primary CNS lymphoma was present in three patients (6%). Cryptococcal meningitis was noted in two (4%) of the patients at autopsy, and Mycobacterium tuberculosis was seen in one (2%) of the patients at autopsy. MR imaging has been shown to be a valuable technique for the detection of encephalopathy in AIDS patients.

CT in the evaluation of the orbit and the bony interorbital distance.

The distance between the orbits and their individual dimensions are important in the diagnosis of craniofacial anomalies. Most observers rely on standard radiographs for measuring the bony interorbital distance. Tomography of the skull base and orbital computed tomography (CT) can also be used. This article describes the normal range of the bony interorbital distance and other useful orbital linear and angular measurements as determined from a series of CT scans of the orbits in 400 adults who had CT for other purposes. The normal interorbital distance measured at the posterior border of the frontal processes of the maxilla on nonrotated scans, in the plane of the optic nerve, ranges from 2.29 to 3.21 cm (average, 2.67 cm) in men and 2.29 to 3.20 cm (average, 2.56 cm) in women. The widest interorbital distance lies behind the posterior poles of the globes. This ranges from 3.16 to 4.10 cm (average, 3.37 cm) in men and 2.93 to 3.67 cm (average, 3.20 cm) in women.

CT of the normal larynx.

The ability of CT to depict cross-sectional anatomy allows the radiologist and the laryngologist to build a clear three-dimensional image of the site and extent of laryngeal diseases. This paper reviews normal CT anatomy of the larynx.

Uveal melanoma, choroidal hemangioma, and simulating lesions. Role of MR imaging.

Malignant uveal melanomas are the most common primary intraocular malignant tumors in adults. Choroidal hemangiomas are congenital, benign, vascular lesions that may be confused with malignant uveal melanomas on clinical examination. The MR imaging characteristics of uveal melanomas and choroidal hemangiomas are different, making diagnostic differentiation possible with a high degree of accuracy. This article describes the MR imaging features of uveal melanoma, choroidal hemangioma, and other simulating lesions.

Preoperative imaging anatomy of nasal-ethmoid complex for functional endoscopic sinus surgery.

Endoscopic sinus surgery has become an increasingly popular surgical procedure. Functional endoscopic sinus surgery is based on the hypothesis that the ostiomeatal complex is the key area in the pathogenesis of chronic sinusitis. This article discusses the concept of functional endoscopic sinus surgery, the anatomy of the ostiomeatal complex, and the imaging anatomy of the ostiomeatal complex.

Nonepithelial tumors of the paranasal sinuses and nasal cavity. Role of CT and MR imaging.

This article reviews some of the applications of computed tomographic (CT) and magnetic resonance (MR) imaging in the clinical investigation of nonepithelial tumors and tumorlike lesions of the sinonasal tract. Sixty selected patients primarily with various nonepithelial tumors of the sinonasal tract were included in this study. The MR characteristics of many of these lesions are described.

Uveal melanoma and similar lesions: the role of magnetic resonance imaging and computed tomography.

The uvea provides a suitable substrate for tumor cells because it is the most vascular portion of the eye. Most primary and metastatic ocular neoplasms involve the choroid, with the most common being malignant melanoma. We review the features of uveal melanomas seen on MRI and CT images and evaluate certain neoplastic and non-neoplastic intraocular lesions that may simulate uveal melanomas.

Computed tomography scanning in the evaluation of ocular motility disorders.

Ocular muscle disturbances (strabismus) are common disorders affecting two to four per cent of the population. Until recently, CT and MRI have not been used extensively in the diagnosis of congenital and acquired conditions causing strabismus. In this article the value of these scanning techniques in terms of more appropriate therapeutic intervention and further insight into the pathophysiology of these conditions is detailed.

Lacrimal gland and fossa lesions: role of computed tomography.

The lacrimal gland region can be involved in a wide spectrum of orbital pathology, including tumors and inflammatory and lymphoid lesions. This article focuses special attention on benign mixed tumors because of the excellent prognosis for the patient when it is completely excised at first surgery. The appearance of these lesions on CT is detailed in the illustrations of this article, and the findings of experts in the field are presented as well.

Retinal and choroidal detachments: role of magnetic resonance imaging and computed tomography.

This article presents MR and CT images of certain inflammatory and neoplastic choroidal and retinal disorders that are associated with retinal and choroidal detachment. The characteristic MR and CT features of retinal and choroidal detachments in many cases can assist ophthalmologists and radiologists in arriving at correct diagnoses of ocular diseases.