The effect of metallic dental restorations and implants in causing patient discomfort and artefacts during magnetic resonance imaging of the head and neck.

Context: Patients with metallic dental objects in their oral cavity are often associated with discomfort or artefacts during magnetic resonance imaging (MRI) of the head and neck. Aim: This study was conducted to evaluate the effects of metallic dental objects in causing patient discomfort and artefacts during MRI of the head and neck region. Design: This is an observational study including 538 participants from various specialized MRI centres in Kozhikode. Methods and Material: MRI records of 538 participants who underwent head and neck MRI as a part of their medical treatment were collected. With the help of questionnaire and clinical examination, the type of metallic dental object in the patient's oral cavity was identified. After examining the MRI images, four categories of artefacts were established. In MRI brain, artefacts in three different sequences were also studied. Statistical Analysis Used: The significance of the difference between proportions was analysed by the Chi-square test. Results: Artefacts were found in 65 cases with metallic dental objects but none of the participants had experienced any kind of discomfort. The artefact formation significantly depended on the type of metallic dental restoration in the patient's oral cavity. Orthodontic braces and titanium bone plate created severe artefacts in head and neck MRI making interpretation almost impossible. In the MRI brain, diffusion-weighted imaging is most sensitive to artefact followed by fluid-attenuated inversion recovery. Conclusions: Artefacts were found in 65 cases with metallic dental restorations but none of the participants had experienced any kind of discomfort.

Autonomic dysreflexia in acute disseminated encephalomyelitis.

Autonomic dysreflexia occurs in patients with spinal cord injury, and is characterized by unbalanced sympathetic discharge, precipitated by noxious stimuli from a site below the spinal cord lesion. An 11-year-old boy with acute disseminated encephalomyelitis and spinal cord involvement manifested episodes of intense flushing and sweating, confined to the head and neck region, and associated with hypertension and tachycardia. His signs improved after changing a partly blocked bladder catheter. The clinical features suggested autonomic dysreflexia. Early recognition of autonomic dysreflexia is important because removal of the trigger precipitating the event may be life-saving.