[Pathology of the cerebellopontine angle]. / Pathologie de l'angle pontocérébelleux.

The pathology of the cistern of the cerebellopontine angle is primarily that of the nervous and vascular structures that it contains and of the meninges that line it. Knowledge of its anatomy makes it possible to understand and search for a rare pathology, the hemifacial spasm, due to a conflict between the facial nerve and the vertebral artery and the posterior inferior cerbellerar artery. However, the pathology of the cerebellopontine angle remains especially tumoral. Imaging should not only make the diagnosis but also make an exhaustive, pretherapy, and accurate assessment of the three main tumours found in this area: the vestibular schwannoma, the meningioma, and the epidermoid cyst.

Bilateral dystrophic ossification of the thyroid cartilage appearing as symmetrical laryngeal masses.

Primary cartilaginous lesions of the larynx are relatively uncommon. We present a case of bilaterally pseudocystic lesion of the thyroid cartilage that demonstrated progressive calcification. Pathologic analysis showed features suggesting a dystrophic lesion with no evidence of malignancy. We hypothesize that repetitive microtrauma related to muscular overuse probably led to inflammatory changes at tendinous insertions on the laryngeal cartilage and resulted in dystrophic ossification of the laryngeal cartilage.

[Von Hippel-Lindau disease: recent advances in genetics and clinical management]. / Maladie de von Hippel-Lindau: progrès génétiques et cliniques récents.

Von Hippel-Lindau (VHL) disease is a hereditary cancer syndrome that predisposes to the development of a panel of highly vascularized tumors including CNS and retinal hemangioblastomas, endolymphatic sac tumors, clear-cell renal cell carcinomas (RCC), pheochromocytomas and pancreatic neuroendocrine tumors. CNS hemangioblastomas and RCC are the two main life-threatening manifestations. The disease is caused by germline mutations in the VHL tumor-suppressor gene that plays a major role in regulating the oxygen-sensing pathway by targeting the hypoxia-inducible factor HIF for degradation in proteasome. Somatic inactivation of the VHL gene occurs also in most sporadic RCC and sporadic CNS hemangioblastomas. The demonstration of the critical role of VHL in angiogenesis is paving the way for the development of new specific drugs that could represent an attractive potential treatment for VHL but also for sporadic RCC and other cancers.

Intractable hiccups: the role of cerebral MR in cases without systemic cause.

PURPOSE: To look for central nervous system abnormalities as possible causes of intractable hiccups. METHODS: Of a series of 50 patients with chronic (ie, lasting more than 48 hours) hiccups, a prospective study identified a subgroup of 9 patients with no clinical or gastroesophageal abnormalities (according to endoscopy, pH monitoring and manometry). We performed in all 9 patients brain and upper cervical cord MR examination with precontrast and postcontrast T1- and T2-weighted sequences. A study of the last cranial nerves was done with thin T2-weighted imaging (constructive interference in a steady state sequence). The cervical cord and parapharyngeal space were systematically explored using coronal T2- and sagittal T1-weighted imaging. RESULTS: Five of these 9 patients had definite MR abnormalities located in the temporal lobe (3 cases), cerebellopontine angle (1 case), or areas of high signal intensity compatible with demyelination (1 case). The relationship between hiccups and infratentorial abnormalities in 2 cases was doubtful (vascular loop and prominent posterior condylar canal). MR findings in 2 cases were considered normal. CONCLUSIONS: Brain MR is a useful investigation in patients with chronic hiccups when gastroesophageal lesions are either excluded or too mild to account for an intractable hiccup.

CT and MR findings of Michel anomaly: inner ear aplasia.

In 1863, Michel described a condition characterized by a total absence of differentiated inner ear structures associated with other skull base anomalies, including an abnormal course of the facial nerve and jugular veins. Michel aplasia clearly differs from Michel dysplasia, in which arrest of embryologic development occurs later. Recently, the role of otic capsule formation on mesenchymal differentiation was reported as well as the impact of the genetic deletion of the homeobox gene on the development of the ear, cranial nerves, and hindbrain. We report two patients with a total absence of inner ear structures bilaterally, illustrating the characteristic appearance of Michel aplasia and associated skull base anomalies.

SAPHO syndrome of the temporomandibular joint associated with sudden deafness.

We report a case of arthritis of the temporomandibular joint (TMJ) associated with sclerosing osteomyelitis of the mandible and temporal bone, causing deafness. The presence of a palmoplantar pustulosis established the diagnosis of SAPHO syndrome. SAPHO (an acronym referring to synovitis, acne, palmoplantar pustulosis, hyperostosis, and osteitis) syndrome is defined by the association of characteristic osteoarticular and dermatologic manifestations, with diffuse sclerosing osteomyelitis of the mandible being a part of this entity. We review the literature of SAPHO syndrome with mandibular manifestations and discuss the mechanisms of inflammatory spread from the TMJ to the cochlea. To our knowledge, this is the first description of skull base involvement in a patient with SAPHO syndrome leading to sudden deafness.

Merkel cell carcinoma: a rare cause of hypervascular nasal tumor.

Cutaneous neuroendocrine carcinoma, first described in 1972, is an aggressive disease usually occurring in sun-exposed skin. Other sites have been described, however; such tumors occasionally occur within the nasal fossa. A high rate of metastasis (>30%) explains the poor prognosis. Descriptions of the imaging features of these tumors, mainly located in cutaneous region, are rare. We therefore present the imaging features of two cases of Merkel cell carcinoma involving the sinonasal region, suggestive of a hypervascular tumor.

Postoperative complications in otospongiosis: usefulness of MR imaging.

BACKGROUND AND PURPOSE: Sensorineural hearing loss (SNHL) is a rare complication of stapes surgery that may arise for many reasons. Usually, the pathogenesis of SNHL can be established by clinical and CT examinations. The purpose of this study was to evaluate the utility of MR imaging when CT findings are normal or not contributive. METHODS: Eleven patients with SNHL (in some instances, associated with vertigo) after stapedectomy, in whom CT showed no well-defined cause, were examined by MR imaging. RESULTS: MR studies established the additional findings of reparative intravestibular granuloma (n = 2), intralabyrinthine hemorrhage (n = 1), and bacterial labyrinthitis (n = 1). In five cases, MR findings were similar to CT findings. In two cases, CT and MR results were normal. Revision surgery was performed in five patients and confirmed the MR findings in each case. CONCLUSION: If CT is not contributive as to the origin of SNHL and vertigo occurring after stapes surgery, then MR imaging may be helpful in these patients.

The petrosquamosal sinus: CT and MR findings of a rare emissary vein.

BACKGROUND AND PURPOSE: Morphologic changes in the dural sinuses and emissary veins of the posterior fossa relate closely to the development of the brain. We report characteristic findings of imaging in six patients with a rare and forgotten emissary vein called the petrosquamosal sinus (PSS). METHODS: From a larger group of patients with ear abnormalities, we selected six patients from three ENT imaging centers, because they had CT features suggestive of a PPS. This was the criterion for inclusion in this retrospective study. They were explored by high-resolution CT (HRCT) of the temporal bone. MR venography was performed in three patients to determine the presence and patency of the emissary vein. RESULTS: The PPS was bilateral in two patients and unilateral in the other four. It affected mainly the left side (left:right ratio, 5:3). Three patients had associated inner ear (n = 2) or middle ear malformations (n = 1). Five of six patients had jugular vein hypoplasia, with development of emissary mastoid veins in three patients. CONCLUSION: Petrosquamosal sinus can be identified on HRCT in a typical location. It is encountered more frequently in patients referred for congenital abnormalities of the skull base. This rare anatomic variant should be assessed before surgical treatment, because proper identification of these large venous channels would be of interest to the surgeon.

Papillary adenoma of endolymphatic sac origin: a temporal bone tumor in von Hippel-Lindau disease. Case report.

This report describes a patient with von Hippel-Lindau disease who presented with an 8-year history of a slow-growing, locally invasive vascularized lesion of the temporal bone involving the cerebellopontine angle. The mass, studied by computerized tomography scanning and magnetic resonance imaging techniques, was partly cystic in appearance. After removal of the mass, pathological studies confirmed a papillary cystic tumor with characteristics that have been described in tumors with an endolymphatic sac origin. These rare neoplasms constitute a distinct pathological entity and deserve wider recognition.

Cochlear implant assessment: imaging issues.

Cochlear implants are electronic auditory prostheses used to rehabilitate deafened persons who have lost their hair cells. They are partly worn externally and partly implanted in the ear. They provide a direct stimulation of the spiral ganglion cells of the cochlear nerve by bypassing the destroyed hair cells. The objectives of this article are to summarise what head and neck surgeons need to know before cochlear implantation and to describe the imaging study protocol used and anomalies to look for. A few explanations are resumed about placement of a brainstem implant.

Imaging of the vestibule.

PURPOSE: State-of-the-art imaging of the normal and pathologic vestibule. METHODS AND MATERIAL: This study is based on the experience of three French imaging centers (Val de Grâce, Bégin, and Saint-Antoine hospitals) working with 1- and 1.5-tesla magnetic resonance units and high-resolution computed tomography, and it includes a review of the literature. Computed tomography is performed with a high-resolution program, matrix 512 x 512, field of view 9.6 cm, joined 1-mm section, overlapped sections every 0.5 mm, axial and coronal sections, or reformatted images. High-resolution magnetic resonance imaging (matrix 512 x 384), field of view 18 cm, is used with fast T2-weighted sequences (sections 3 or 2 mm thick, constructive interference in steady state, T2-weighted gradient echo sequence three-dimensional Fourier transformation). A joined section of 0.7 mm in any direction is obtained if necessary. Superimposition of computed tomography and magnetic resonance imaging with a stereotactic technique by identification of identical anatomic points is sometimes used. RESULTS: We review the interest and place of computed tomography and magnetic resonance imaging in the diseases of the labyrinth and internal auditory canal related to abnormal vestibular functions: inflammatory labyrinthitis, vestibular hemorrhages, sclerosing and ossifying labyrinthitis, traumatism, malformations, perilymphatic fistulas, otosclerosis, tumors, cochleovestibular neuritis, and hydrops of the endolymphatic system.

Pulsatile and nonpulsatile tinnitus: a systemic approach.

Tinnitus is an annoying symptom that affects approximately 10% of the population. Unfortunately, in more than 60% of patients, even an extensive workup may not lead to diagnosis, partly because of the diverse causes of the symptom. The imaging protocol study should therefore be adapted to the history of the patient, and each imaging study should underline which etiologies it may exclude. Imaging studies should only be performed after a careful clinical examination and otoscopy. Some characteristic clinical findings are suggestive of such etiologies as pulsed synchronous tinnitus or positional tinnitus, varying with the venous pressure. History of associated neurological deficits, nerve palsies, trauma, ischemic attacks, and visual disturbance (in overweight women) may modify the imaging protocol. Study of the brain and the cervical vessels should always be included to rule out a benign intracranial hypertension. Path and size of the internal carotid artery should be systematically described with regard to the size of the jugular vein and presence of emissary veins. Objective pulsatile tinnitus and tinnitus in children always need a careful imaging study.

[Lyrical and musical auditive mental imagery in functional MRI]. / Imagerie magerie mentale auditive lyrique et musicale en IRM fontionnelle d'activation.

PURPOSE: to explore with functional MRI cerebral areas involved in musical and lyrical sounds signal processing with the mental imagery method. MATERIAL: and METHODS: nine volunteers (mean age: 27 years old) underwent functional MRI with BOLD contrast at 1.5 T. Box-car paradigms of partial recollections of musical or lyrical memories tasks were performed. Statistical correlations mappings were calculated and superimposed on previously realigned anatomical reference imaging to observe activated cerebral areas. RESULTS: all except one subjects had activation areas in primary and secondary auditive cortices in the temporal Heschl gyrus and the Planum Temporale, unilaterally (n=2) or bilaterally (n=6) during both mental tasks. Contralateral activation improvement was observed in 4 cases when the lyrical tasks were performed. Temporal and insular regions involved in language processing were observed in eight of nine subjects. CONCLUSION: auditive mental imagery can show in functional MRI cerebral areas involved in auditive functions and some of the areas involved in language processing.

Diffusion-weighted imaging in a case of wernicke encephalopathy.

In a chronic alcoholic patient with progressive confusion, which was consistent with the clinical diagnosis of Wernicke encephalopathy, T2-weighted, FLAIR and diffusion weighted (DWI) MR imaging depicted brain abnormalities located in both medial thalamic nuclei. Apparent Diffusion Coefficient (ADC) measurements in these regions shown unexpected normal values, referring to Wernicke pathological findings and DWI data. DWI may be helpful to diagnose early basal nuclei abnormalities, but may fail to compute ADC values in these locations.

[The foramen rotundum. Anatomy and radiological explorations. Pathology]. / Le foramen rond. Anatomie et exploration radilogiques. Patholgie.

The foramen rotundum is a small canal deeply situated in the base of the skull which represents the way of exit of the maxillary nerve, second branch of the trigeminal nerve. Its precise individualization and analyse is difficult and necessitates a precise and adapted technique as well as a precise knowledge of its anatomical relationships. Its represents a frontier area between the endo- and exocranial spaces. Its involvement which is preferentially related with tumoral pathologies (and particularly with retrograde perineural invasion) profoundly modifies the prognosis of the disease and so should allow soon a multidisciplinary therapeutic discussion.

Lemierre syndrome: usefulness of CT in detection of extensive occult thrombophlebitis.

We report a case of Lemierre syndrome with extensive suppurative thrombophlebitis involving concomitantly the internal jugular, facial and anterior jugular veins. This case illustrates two unusual clinical and imaging features: the lack of characteristic neck symptoms at admission and a negative initial neck US exam. The value of postcontrast CT of the neck and chest for diagnosis of this potentially life-threatening syndrome is illustrated.

[Anatomic variants of paranasal sinuses]. / Les variantes anatomiques des sinus de la face.

During the last 15 years period, the development of functional endoscopic sinus surgery underlines the needs of a better knowledge of sinonasal anatomy and consequently, of sinonasal anatomic variations. These anatomic variations are widely spread into the population and commonly encountered in daily CT practice. The difference of anatomic landmarks during endoscopic surgery can result in bony transgression and increase the difficulties of the surgery. In fact, functional endoscopic surgery is a blind surgery leading to severe complications with medico-legal impact. Therefore, the anatomic sinonasal variations should be depicted in all sinonasal CT imaging studies irrespective of the indications. Moreover, some anatomical variants may cause certain symptoms.

[Imaging of the cochleo-vestibular system]. / Imagerie du systeme cochléo-vestibulaire.

This article will review the main pathologies affecting the vestibulocochlear system from the sensorineural organs to the cerebral cortex. MR imaging has greatly improved detection of these pathologies. Thin slice MR imaging using different pulse sequences now allows improved depiction of anatomical structures. Vestibular schwannoma is by far the most common lesion, but MR imaging allows detection and characterization of rarer lesions in patients often presenting with similar symptoms.

[Imaging of post-traumatic tinnitus, vertigo and deafness]. / Imagerie des acouphènes, vertiges et surdité post-traumatiques.

Tinnitus, hearing loss, and more rarely disequilibrium are common sequela of temporal bone trauma. Hemotympanum may cause a transient and immediate conductive hearing loss. HRCT depicts ossicular dislocation (most frequently incus), producing a long-term conductive hearing loss. Labyrinthine trauma causing neurosensory hearing loss or/and acute vertigo may be depicted by MRI, showing an abnormal non-enhancing high signal T1 of the membranous labyrinthine fluid. MRI also may show low signal T1 and T2 fibrotic areas of the membranous labyrinth, especially of interest if cochlear implant surgery is planned. Perilymphatic fistulas are to be searched in case of fluctuant hearing loss. Both HRCT and MRI may show window damage: filling of the tympanic recess, rupture of the window membrane, intra-vestibular luxation of the stapes, or occasionally pneumolabyrinth.