Evaluation of pharyngolaryngeal region with 3-D computed tomography
ABSTRACT We present a new method of 3-D CT reconstruction with space extraction (volume rendering) technique in this study. The objective of this study is to demonstrate pharyngeal space with 3-D CT images and evaluate the volume change of upper airway in normal individuals and patients with snoring and sleep apnea. Axial CT scanning was taken before 3-D images of upper airway cavity being reconstructed. Then the volume of airway was measured, in each aspect of inspiration, expiration, sleeping, snoring and apnea. Repeat of closing and widening of airway was clearly demonstrated in OSAS (sleep apnea syndrome) patients during their sleep. It was also found that the volume changes of airway corresponded with shape changes. This new method is expected to be helpful in locating obstructive site and estimating surgical outcome of OSAS.
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ABSTRACT: The upper airway lumen is narrower in patients with obstructive sleep apnea syndrome (OSAS) than normal subjects. In this study, we examined changes of the upper airway cross-sectional area in each phase of respiration in different degrees of severity of OSAS with dynamic CT and investigated whether these changes have any correlation with sleep apnea severity parameters, including polysomnography (PSG) and cephalometry. Between May and November 2004, 47 patients who had at least 2 of 3 major symptoms of snoring, daytime somnolence, and apnea with witness were included in this prospective study. As control group, 24 habitual snorers were studied. All patients underwent PSG and upper airway CT. The average number of episodes of apnea and hypopnea per hour of sleep (the apnea-hypopnea index, AHI) was calculated. An AHI of 5 -29 represented mild/moderate OSAS and an AHI > or = 30 represented severe OSAS. Cross-sectional area of the airway at the level of oropharynx and hypopharynx were obtained in each phase of quiet tidal breathing and at the end of both the forced inspiration and expiration. Six standard cephalometric measurements were made on the lateral scout view. All parameters were compared between controls and mild/moderate and severe OSAS groups. Twenty-seven patients had mild/moderate OSAS, and 20 patients had severe OSAS. Patients with severe OSAS had significantly narrower cross-sectional area at the level of uvula in expiration, more inferiorly positioned hyoid bone, and thicker soft palate compared with patients with mild/moderate OSAS (P < .05) and the control group (P < .05). In addition, severe OSAS patients had bigger neck circumference than those in the control group (P < .05). Patients with severe OSAS had significant differences in the parameters. Measurement of the cross-sectional area of oropharynx in expiration can especially be useful for diagnosis of severe OSAS as a new key point.American Journal of Neuroradiology 26(10):2624-9. · 3.68 Impact Factor
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ABSTRACT: Obstructive sleep apnea syndrome is an increasingly common disorder, but the etiology and site of obstruction often remain unknown. The obstruction seldom is imaged or identified. All surgical procedures must be directed toward the anatomic site of obstruction. Currently, it is very difficult to identify the site of obstruction in the awake, nonsupine patient. Therefore, better diagnostic methods must be developed to help direct treatment options and improve surgical outcomes. This article will help surgeons identify possible sites of obstruction and direct surgical intervention.Oral and maxillofacial surgery clinics of North America 11/2009; 21(4):389-402.