[Computed tomography of the upper respiratory tract in patients with apnea]

When deciding on the therapeutic procedure in sleep apnoea syndrome (SAS) it is important to know the anatomical conditions of the upper airways.

We examined on account of SAS, verified by all night monitoring, using the MESAM4 method a total of 60 patients by means of computed tomography (CT). SAS without associated disease was diagnosed in 48 patients. To facilitate comparison of results of (CT) and MESAM4 we defined the MESAM4 score (M4) as the number of desaturations per hour multiplied by their depth (difference between mean minimal and basic saturation). Axial sections, 5mm thick at 5mm intervals were made from the level of the hard palate to the upper trachea in a vertical position to the longitudinal axis of the pharynx in the patient awake at the peak of the inspirium. The air-filled area, sagittal and coronary sections were measured at five levels (nasopharyngeal, velopharyngeal, retrobasilingual, at the level of the hyoid bone and trachea). The results differed significantly from the normal population examined by the same protocol (foreign standards). Macroglossia as a factor promoting SAS was also examined.

The frontal and sagittal reformation reflected, on account of numerous inaccuracies, the actual state only partly. When the borderline between mild and more severe apnoea was set at M4 = 300, the correlation with the retrobasilingual section and coronary and velopharyngeal section was best. The authors suggest a simpler CT examination protocol which improves further the prediction of severity of SAS. The correlation with the body mass index (BMI) and the neck circumference (p < 0.001) confirmed the asset of CT parameters.