Radiological findings in spontaneous cerebrospinal fluid leaks of the temporal bone.

BACKGROUND AND OBJECTIVE: Spontaneous cerebrospinal fluid leak of the temporal bone is an emerging clinical entity for which prompt and accurate diagnosis is difficult given the subtle signs and symptoms that patients present with. This study sought to describe the key temporal bone abnormalities in patients with spontaneous cerebrospinal fluid leak. METHODS: A retrospective cohort study was conducted of adult patients with biochemically confirmed spontaneous cerebrospinal fluid leak. Demographics and radiological features identified on computed tomography imaging of the temporal bones and/or magnetic resonance imaging were analysed. RESULTS: Sixty-one patients with spontaneous cerebrospinal fluid leak were identified. Fifty-four patients (88.5 per cent) underwent both temporal bone computed tomography and magnetic resonance imaging. Despite imaging revealing bilateral defects in over 75 per cent of the cohort, only two patients presented with bilateral spontaneous cerebrospinal fluid leaks. Anterior tegmen mastoideum defects were most common, with an average size of 2.5 mm (range, 1-10 mm). CONCLUSION: Temporal bone computed tomography is sensitive for the identification of defects when suspicion exists. In the setting of an opacified middle ear and/or mastoid, close examination of the skull base is crucial given that this fluid is potentially cerebrospinal fluid.

Imaging of the temporomandibular joint.

Temporomandibular disorders are common, especially in young to middle-aged women, and most settle with supportive treatment. Imaging is indicated for the small percentage of cases that do not respond to conservative management and when the diagnosis is no doubt. The temporomandibular joint (TMJ) is a bilateral synovial articulation between the mandible and skull base. It has an intra-articular disc dividing the joint into superior and inferior compartments and the articular surfaces are lined with fibrocartilage. The normal imaging anatomy of the TMJ is described and illustrated. Different movements occur in each joint compartments: a hinge movement in the inferior joint space and translation or gliding in the superior joint space. Internal derangement is the commonest disorder affecting the TMJ and is most commonly due to disc displacement, followed by osteoarthritis and inflammatory arthritides. The imaging findings, primarily on magnetic resonance imaging (MRI) and computed tomography (CT), of internal derangement and less common disorders of the joint, are reviewed and illustrated. Optimal imaging protocols are discussed with detailed reporting guidelines.

The many faces of periapical inflammation.

Dental periapical inflammation is common and can present with a wide variety of symptoms and signs. These include jaw pain and local soft-tissue inflammation, which may be obviously dental in origin; however, the presentation may also be with a painless mass or draining cutaneous sinus, with facial or ear pain or with symptoms of sinusitis, when the dental cause is not clinically obvious. Radiologists are often the first to recognise the dental source of symptoms in these cases. This recognition requires an awareness of the varied manifestations of periapical sepsis and careful systematic review of the teeth and jaws. The causative periapical lesion may be small and subtle, and there is not always a macroscopic defect in the cortical bone between the lesion and surrounding soft-tissue inflammation. The origin of the referral and the initial imaging technique used can vary. Dental periapical inflammation can also be an incidental finding on imaging. In these cases, it should not be mistaken for more sinister pathology and its presence should be conveyed to the referrer so that appropriate dental treatment can be initiated: this is especially important in patients with malignancy in whom radiotherapy is planned. In cases of severe odontogenic soft-tissue sepsis, a review of the airway and major blood vessels is important. We present cases to illustrate the wide range of clinical and radiological manifestations of periapical inflammatory pathology.

Bilateral intracochlear schwannomas in a patient with no genetic or clinical features of neurofibromatosis type 2.

Schwannomas of the eighth cranial nerve are benign tumours commonly found in the internal auditory meatus or in the cerebellopontine angle. In most cases, they arise from the inferior or vestibular portion of the vestibular nerve. Rarely, these tumours present in the inner ear and are then called intralabyrinthine schwannomas. Bilateral schwannomas are known in neurofibromatosis type 2 (NF2). Bilateral and ipsilateral, multilocular sporadic schwannomas of the eighth cranial nerve have been described as extremely rare findings. This report describes the first case of bilateral sporadic intracochlear schwannomas in a patient with no genetic or clinical features of NF2.

[Bilateral intracochlear schwannomas in a patient with no genetic or clinical features of neurofibromatosis type 2. German version]. / Bilaterale intracochleäre Schwannome bei einer Patientin ohne genetische oder klinische Hinweise auf Neurofibromatose Typ 2.

Schwannomas of the eighth cranial nerve are benign tumours commonly found in the internal auditory meatus or in the cerebellopontine angle. In most cases, they arise from the inferior or vestibular portion of the vestibular nerve. Rarely, these tumours present in the inner ear and are then called intralabyrinthine schwannomas. Bilateral schwannomas are known in neurofibromatosis type 2 (NF2). Bilateral and ipsilateral, multilocular sporadic schwannomas of the eighth cranial nerve have been described as extremely rare findings. This report describes the first case of bilateral sporadic intracochlear schwannomas in a patient with no genetic or clinical features of NF2.

Imaging of adult nasal obstruction.

The commonest causes of nasal obstruction are rhinitis and chronic rhinosinusitis, which affect up to 30% and 14% of the adult population, respectively. The global financial burden is huge, estimated at $5 billion for rhinitis and $8.6 billion for chronic rhinosinusitis per annum in the USA. On referral for imaging, computed tomography (CT) is indicated initially when there is a suboptimal response to medical treatment of these mucosal diseases or there are "red flags," such as persistent unilateral obstruction, epistaxis, pain, and orbital or neurological symptoms. A mass visible at rhinoscopy or endoscopy in the nose or nasopharynx and lymphadenopathy are further indications. The anterior (cartilaginous) nose plays a key role in the aetiology of nasal obstruction as it accounts for 50-75% of the total resistance to airflow in the upper airway. It has been ignored in the imaging literature, but extensively evaluated by clinicians using a range of methods, including CT. Oblique reconstructions perpendicular to the parabolic curve of lamellar airflow provide accurate assessment of the anterior nose. A thorough and systematic approach to assessing the nose addresses the discrepancy between imaging and clinical evaluation of structural causes of nasal obstruction, especially septal deviation, reported in the surgical literature. Nasal tumours are a very uncommon cause of nasal obstruction; magnetic resonance imaging is commonly performed to assess their full extent and improve the specificity of diagnosis.

Imaging of odontogenic sinusitis.

The aetiological relationship between dental disease and procedures and mucosal disease within the maxillary sinus has received extensive attention in the recent otolaryngological and dental literature. In contrast, the concept of an odontogenic cause for sinusitis is not well appreciated by radiologists. Review of the maxillary dentition, the alveolar process, and the relationship of the tooth roots to the floor of the maxillary sinus should be an integral part of interpretation of imaging of the paranasal sinuses. The pathogenesis, clinical presentation, and imaging features of rhinogenic and odontogenic sinusitis are discussed and compared. Clinical definitions of rhinosinusitis are explained and the huge impact on healthcare of this disease is briefly discussed. Periapical inflammatory lesions, post-extraction oroantral communication, and procedures used to augment the alveolar process prior to placement of dental implants are the commonest causes of odontogenic sinusitis. Current estimates are that an odontogenic cause for maxillary sinusitis is present in 25-40% of cases. The incidence of odontogenic sinusitis is rising, extension outside the maxillary sinus is common, and the diagnosis is often delayed, resulting in inappropriate and failed treatment. Differentiation of rhinological and odontogenic causes of sinusitis is usually difficult on clinical grounds and imaging plays a key role in the distinction.

Trends in maxillofacial imaging.

Maxillofacial imaging encompasses radiology of the teeth and jaws, including the temporomandibular joints. Modalities used include intra-oral radiographs, panoramic tomography, cephalograms, cone-beam computed tomography, computed tomography, magnetic resonance imaging, ultrasound, and radionuclide imaging. Common indications for imaging are impacted and supernumerary teeth, dental implants, inflammatory dental disease, and fibro-osseous lesions, cysts, and masses of the jaws. Osteonecrosis of the jaws may follow radiotherapy or the use of bisphosphonates and other drugs. Imaging of the temporomandibular joints and the potential role of imaging in obstructive sleep apnoea are also discussed.

Dental panoramic tomography: an approach for the general radiologist.

Dental panoramic tomography is commonly presented to radiologists with no dental training for interpretation. An overview of the technique, basic anatomy and nomenclature and common pathology is presented with examples to show the anatomy and nomenclature, the artefacts and common pathology.