Use Of MRI Imaging in diagnosing Snoring and Sleep Apnea
Dr.K.O.Paulose FRCS DLO, Consultant ENT Surgeon, Jubilee Hospital, Trivandrum, Kerala, India
The condition is common in males aged between 30-60 years. The clinical symptoms include history of snoring, daytime hypersomnia and nocturnal choking or gasping. Obesity and ingestion of alcohol are predisposing factors. In some patients the structural compromise is due to anatomical factors such as micrognathia, retrognathia, adenotonsillar hypertrophy and macroglossia.
Velopharynx is the most common site of pharyngeal obstruction in these patients. Two factors maintain the patency of the pharyngeal airway in healthy persons even while sleeping: anatomic factor and a functional factor (synchronisation of the activities of the muscles of upper respiratory tract and nerves).
Polysomnography is the investigation of choice for establishing the diagnosis of SAS and for determining its severity. Because CT scan has high spatial resolution and provides tomographic images, it is often used to diagnose pharyngeal obstruction. However CT provides only axial images and cannot image the entire pharyngeal airway in a single plane.
MR is a non-invasive modality that allows examination of the entire pharynx in multiple planes and in a short time, with no radiation exposure as compared to CT. It provides good temporal and a high contrast resolution and can evaluate the pharynx on a real time basis.MR is the best non-invasive modality for evaluation and follow-up of patients with obstructive sleep apnea.