Imaging of the temporomandibular joint (TMJ) is continuously evolving with advancement of imaging technologies. Many different imaging modalities are currently used to evaluate the TMJ. Magnetic resonance imaging is commonly used for evaluation of the TMJ due to its superior contrast resolution and its ability to acquire dynamic imaging for demonstration of the functionality of the joint. Computed tomography and ultrasound imaging have specific indication in imaging of the TMJ. This article focuses on state of the art imaging of the temporomandibular joint. Relevant normal anatomy and biomechanics of movement of the TMJ are discussed for better understanding of many TMJ pathologies. Imaging of internal derangements is discussed in detail. Different arthropathies and common tumors are also discussed in this article.

Skull base osteomyelitis is a relatively rare condition, generally occurring as a complication of advanced otologic or sinus infection in immunocompromised patients. Skull base osteomyelitis is generally divided into 2 broad categories: typical and atypical. Typical skull base osteomyelitis occurs secondary to uncontrolled infection of the temporal bone region, most often from necrotizing external otitis caused by Pseudomonas aeruginosa in a patient with diabetes. Atypical skull base osteomyelitis occurs in the absence of obvious temporal bone infection or external auditory canal infection. It may be secondary to advanced sinusitis or deep face infection or might occur in the absence of a known local source of infection. Atypical skull base osteomyelitis preferentially affects the central skull base and can be caused by bacterial or fungal infections. Clinically, typical skull base osteomyelitis presents with signs and symptoms of otitis externa or other temporal bone infection. Both typical and atypical forms can produce nonspecific symptoms including headache and fever, and progress to cranial neuropathies and meningitis. Early diagnosis can be difficult both clinically and radiologically, and the diagnosis is often delayed. Radiologic evaluation plays a critical role in the diagnosis of skull base osteomyelitis, with CT and MR imaging serving complementary roles. CT best demonstrates cortical and trabecular destruction of bone. MR imaging is best for determining the overall extent of disease and best demonstrates involvement of marrow space and extraosseous soft tissue. Nuclear medicine studies can also be contributory to diagnosis and follow-up. The goal of this article was to review the basic pathophysiology, clinical findings, and key radiologic features of skull base osteomyelitis. ABBREVIATIONS: ASBO ¼ atypical skull base osteomyelitis; EAC ¼ external auditory canal; Ga-67 ¼ gallium-67 citrate; IgG4 ¼ immunoglobulin G4; Tc99m MDP ¼ technetium Tc99m methylene diphosphonate; NEO ¼ necrotizing external otitis; SBO ¼ skull base osteomyelitis; TSBO ¼ typical skull base osteomyelitis S kull base osteomyelitis (SBO) is a rare, potentially life-threatening infection that can present a diagnostic challenge clinically and radiologically. [1][2][3][4] While reports differ in terminology, there are generally 2 categories of SBO: typical and atypical. Typical SBO (TSBO) is the most common and classically occurs in elderly patients with diabetes as a result of necrotizing external otitis (NEO) caused by Pseudomonas species. (Fig 1). 1,3 Atypical SBO (ASBO), also called central SBO, predominantly involves the basisphenoid and basiocciput and occurs without preceding otologic infection (Fig 2). 2,5 Recognition of SBO is increasing, and it is clear that radiologic evaluation plays a critical role in diagnosis and management. The goal of this article was to review the pathophysiology, clinical presentation, and detailed radiologic findings using multiple modalities including CT, MR imaging, and nuclear medicine.

Purpose: COVID-19-associated rhino-orbital-cerebral mucormycosis (ROCM) has reached epidemic proportion during India’s second wave of COVID-19 pandemic, with several risk factors being implicated in its pathogenesis. This study aimed to determine the patient demographics, risk factors including comorbidities, and medications used to treat COVID-19, presenting symptoms and signs, and the outcome of management. Methods: This was a retrospective, observational study of patients with COVID-19-associated ROCM managed or co-managed by ophthalmologists in India from January 1, 2020 to May 26, 2021. Results: Of the 2826 patients, the states of Gujarat (22%) and Maharashtra (21%) reported the highest number of ROCM. The mean age of patients was 51.9 years with a male preponderance (71%). While 57% of the patients needed oxygen support for COVID-19 infection, 87% of the patients were treated with corticosteroids, (21% for > 10 days). Diabetes mellitus (DM) was present in 78% of all patients. Most of the cases showed onset of symptoms of ROCM between day 10 and day 15 from the diagnosis of COVID-19, 56% developed within 14 days after COVID-19 diagnosis, while 44% had delayed onset beyond 14 days. Orbit was involved in 72% of patients, with stage 3c forming the bulk (27%). Overall treatment included intravenous amphotericin B in 73%, functional endoscopic sinus surgery (FESS)/paranasal sinus (PNS) debridement in 56%, orbital exenteration in 15%, and both FESS/PNS debridement and orbital exenteration in 17%. Intraorbital injection of amphotericin B was administered in 22%. At final follow-up, mortality was 14%. Disease stage >3b had poorer prognosis. Paranasal sinus debridement and orbital exenteration reduced the mortality rate from 52% to 39% in patients with stage 4 disease with intracranial extension ( p < 0.05). Conclusion: Corticosteroids and DM are the most important predisposing factors in the development of COVID-19-associated ROCM. COVID-19 patients must be followed up beyond recovery. Awareness of red flag symptoms and signs, high index of clinical suspicion, prompt diagnosis, and early initiation of treatment with amphotericin B, aggressive surgical debridement of the PNS, and orbital exenteration, where indicated, are essential for successful outcome.

A major goal of this pilot study was to quantify intramyocellular lipids (IMCL), extramyocellular lipids (EMCL), unsaturation index (UI) and metabolites such as creatine (Cr), choline (Ch) and carnosine (Car), in the soleus muscle using two-dimensional (2D) localized correlated spectroscopy (L-COSY). Ten subjects with type 2 diabetes (T2D), controlled by lifestyle management alone, and 9 healthy control subjects, were studied. In T2D patients only, the following measurements were obtained: body mass index (BMI); waist circumference (WC); abdominal visceral and subcutaneous fat quantified using breath-held magnetic resonance imaging (MRI); a fasting blood draw for assessment of glucose, insulin, and estimation of homeostasis model assessment of insulin resistance (HOMA-IR), HbA1c, and high-sensitivity c-reactive protein (hs-CRP). Analysis of the soleus muscle 2D L-COSY spectral data showed significantly elevated IMCL ratios with respect to Cr and decreased IMCL UI in T2D when compared to healthy subjects (P < 0.05). In T2D subjects, Pearson correlation analysis showed a positive correlation of IMCL/Cr with EMCL/Cr (0.679, P < 0.05) and HOMA-IR (0.633, P < 0.05), and a non-significant correlation of visceral and subcutaneous fat with magnetic resonance spectroscopy (MRS) and other metrics. Characterization of muscle IMCL and EMCL ratios, UI, and abdominal fat, may be useful for the noninvasive assessment of the role of altered lipid metabolism in the pathophysiology of T2D, and for assessment of the effects of future therapeutic interventions designed to alter metabolic dysfunction in T2D.

Free breathing navigator-gated noncontrast 3D SSFP MRA with nonselective radiofrequency excitation provides high image quality and sufficient SNR and CNR for confident evaluation of thoracic central veins.