Imaging of Trigeminal Neuralgia and Other Facial Pain.

We review and illustrate the radiology of facial pain, emphasizing trigeminal neuralgia, relevant anatomy, current classification, concepts about etiology, and the role of imaging and its influence on the choice of treatment. We discuss glossopharyngeal neuralgia, other neuropathic causes of facial pain, postinflammatory and neoplastic causes, and nociceptive (end-organ) causes of facial pain, as well as referred otalgia. Other conditions that may present with facial pain, including trigeminal autonomic cephalgias and giant cell arteritis, are reviewed briefly. We discuss the elements of a comprehensive MR imaging protocol to enable detection of these diverse causes of facial pain.

Imaging of temporomandibular disorder and its mimics.

Temporomandibular disorders are common, especially in young to middle-aged women, and most settle with supportive treatment. MRI is the accepted reference standard for the evaluation of the temporomandibular joint and is indicated when significant internal derangement is suspected, in those who do not respond to conservative management and when the diagnosis is no doubt. Multiple pathological processes involving the temporal bone, upper pharynx and neck can mimic temporomandibular disorder secondary to anatomical proximity and referred pain related to shared sensory innervation.

Imaging of orofacial pain.

BACKGROUND: Orofacial pain is a common complaint, with an estimated 75% of cases caused by dental disease, specifically a diseased pulp. A small percentage of orofacial pain cases will require specialist referral most commonly to oral medicine specialists or oral and maxillofacial surgeons from a dental perspective, or otolaryngologists or neurologists from a medical perspective. IMAGING MODALITIES: Following a thorough history and clinical examination, imaging is often required to narrow the differential diagnosis or answer a specific query related to the final diagnosis. A range of imaging modalities can be used to evaluate orofacial pain including dental panoramic tomography (DPT), intraoral radiographs, cone beam computed tomography (CBCT), multidetector computed tomography (MDCT), ultrasonography (US), magnetic resonance imaging (MRI) and nuclear medicine. IMAGING PROTOCOLS: This paper provides a guideline outlining imaging protocols for categories of facial pain divided into: (a) unilateral odontalgia; (b) unilateral facial pain; (c) combined unilateral odontalgia and facial pain; (d) trigeminal neuralgia; (e) trigeminal neuropathic pain with or without other sensory, autonomic or motor features; (f) temporomandibular joint disorders and associated pain; (g) referred pain and (h) non-specific orofacial pain. CONCLUSION: Imaging for orofacial pain should be tailored to answer a specific query related to the aetiology of the reported pain. This should result in a specific diagnosis or narrowing of the differential diagnosis as possible causes of orofacial pain are eliminated. Choosing the correct imaging modality and protocol based on the pain category is important for efficient and effective pain diagnosis and management.

Adult obstructive sleep apnoea: Pathogenesis, importance, diagnosis and imaging.

Obstructive sleep apnoea (OSA) is a serious worldwide health problem. Moderate-to-severe OSA has been found in up to 50% of men and 25% of women in the middle-aged population. It results in a fourfold increase in all causes of mortality. The prevalence of OSA is underestimated, partly due to absence of symptoms but also lack of knowledge amongst the population at large as well as sectors of the medical profession. Imaging, performed predominantly by clinicians and research scientists, has been integral to evaluating the anatomical basis of OSA. Increased nasal resistance and a narrowed and elongated oropharynx lead to increased collapsibility of the upper airway, predisposing to airway collapse and apnoea during sleep when there is reduction in tone of the pharyngeal dilator muscles. Unfortunately, a significantly narrowed upper airway is usually ignored by radiologists: it is not part of their reporting 'check-list'. The imaging findings in the upper airway that are strongly associated with OSA and its sequelae in various organ systems are discussed. Imaging can strongly suggest OSA; the diagnosis requires a polysomnogram for confirmation. Treatment of moderate-to-severe disease is primarily with positive airway pressure applied by a nasal or oral mask which splints the upper airway. Although highly effective, compliance is limited and other treatment modalities are increasingly being utilized.

Imaging of adult obstructive sleep apnoea.

Obstructive sleep apnoea (OSA) is characterised by recurrent upper airway collapse during sleep resulting in chronic and repetitive hypoxia, hypercapnia, subsequent arousal and fragmented sleep. Symptoms are insidious and diagnosis is usually delayed. Moderate to severe OSA has serious health implications with significant increase in all causes of mortality in patients with the condition as compared with unaffected individuals. The prevalence of OSA in the 30-70 year age group is estimated at 27% of males and 11% of females and it increases with age. 80% of affected individuals are obese and as obesity rates rise, so has the prevalence of OSA. An overnight polysomnogram (PSG) is required for a definitive diagnosis of OSA. Imaging has played a fundamental role in the evaluation of the anatomical factors associated with recurrent upper airway collapse and the pathogenesis of OSA. The upper airway is frequently imaged by radiologists, providing an opportunity to detect features that are strongly associated with unsuspected OSA and to raise the possibility of this diagnosis. The gold standard of treatment is continuous positive airway pressure (CPAP) which acts as a pneumatic splint for the upper airway. However, efficacy is frequently limited by poor tolerance; clinicians and patients are increasingly opting for one of a range of surgical procedures. Dedicated imaging protocols can be performed for evaluation of the upper airway to aid surgical planning.

Computed tomography of the temporomandibular joint.

We present a pictorial review of the spectrum of temporomandibular joint (TMJ) pathology diagnosed with CT. Although MRI is the modality of choice for most TMJ pathology, CT is useful when MRI is contraindicated or not accessible. With attention to technique and viewing conditions, CT is capable of showing internal disc derangement, arthritis, neoplasms and non-TMJ regional pathology at a relatively low radiation dose.

Rotation of the osseous spiral lamina from the hook region along the basal turn of the cochlea: results of a magnetic resonance image anatomical study using high-resolution DRIVE sequences.

PURPOSE: To define the rotational anatomy of the osseous spiral lamina (OSL) at the hook region and along the basal turn of the cochlea and to illustrate the potential utility of high-resolution MRI images to study inner ear ultrastructure. METHODS: Retrospective review of high-resolution temporal bone MRI images in 20 consecutive adult patients referred for imaging unrelated to hearing loss. The main outcome measure utilised images in an oblique sagittal plane to measure the rotation of the OSL relative to the vertical axis in the hook region and along the basal turn of the cochlea. RESULTS: The right OSL is noted to rotate in a clockwise direction as one proceeds anteriorly; over the same distance, the left OSL rotates in an anti-clockwise direction. The average overall rotation for all subjects as measured over a distance of 1-7 mm from the posterior margin of the round window was 25.95°. Inter-subject variability was noted. CONCLUSIONS: Prominent rotation of the OSL was noted in the hook region, this being most pronounced in the proximity to the round window. This concept may have implications for cochleostomy site selection with implant surgery. The study highlights the feasibility of high-resolution MRI to be used to systematically study variations in intra-cochlear anatomy.

Current concepts in maxillofacial imaging.

A review of state-of-the-art maxillofacial imaging is presented. Current imaging techniques include intra-oral radiographs, dental panoramic tomography, multidetector helical computed tomography, cone-beam computed tomography (CBCT) and magnetic resonance imaging (MRI). The commonest conditions encountered in clinical radiological practice are reviewed, including maxillofacial deformities, complicated dental impactions, maxillofacial trauma, jaw lesions (cysts, neoplasms, fibro-osseous lesions (FOLs) and infections), and temporomandibular joint pathology. Pre-operative assessment for dental implant placement is also briefly reviewed.

Dental panoramic tomography: what the general radiologist needs to know.

This article provides an overview of the technique of dental panoramic tomography (DPT), including examples of common radiographic errors. Basic radiographic anatomy and current dental nomenclature and notation are also outlined. Dental disease, namely caries, periapical disease and periodontitis, and the appearance of the alveolar and basal bone structures are illustrated.