Obstruction of the upper airway is a major challenge for anesthesiologists administering general anesthesia in spontaneously breathing children with adenotonsillar hypertrophy. Lateral positioning is a simple treatment for obstructive sleep apnea. In this study, we examined the effects of body position shifting and common airway maneuvers such as chin lift and jaw thrust on airway patency (stridor score and upper airway dimensions by endoscopy) in anesthetized children scheduled for adenotonsillectomy. Eighteen children aged 1-11 yr were anesthetized with sevoflurane. During spontaneous breathing with 5% sevoflurane and 100% oxygen, upper airway dimensions and stridor score were recorded. After baseline recording, chin lift and jaw thrust were performed in both the supine and the lateral decubitus position. Chin lift, jaw thrust, and lateral position increased the airway dimensions and improved the stridor score. Moreover, lateral positioning enhanced the effects of these airway maneuvers on airway patency. We concluded that lateral positioning combined with airway maneuvers provided better airway patency for anesthetized children with adenotonsillar hypertrophy.

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Purpose: Although the signal-to-noise ratio (SNR) currently used in the field of medical X-ray CT is utilized for local image evaluation in a linear system, it is not used as a comprehensive evaluation index for an entire image. Additionally, since X-ray CT cannot produce a noiseless image for obtaining the signal power required to calculate the SNR, it is impossible to calculate SNR precisely even applying the conventional method. To resolve these problems, we propose SNR * , which is a new method for calculating the estimated value of SNR that can evaluate an entire image even when the original image cannot be obtained. Methods: First, we obtained SNR * using the signal power and noise power calculated respectively from covariance and the difference in the pair of observed images, which are noise-containing images scanned under the same imaging conditions. Next, we verified the error and the accuracy of SNR * . Third, we demonstrated the behavior and accuracy of the SNR * applied to the actually observed image. Results: In the verification experiment, the relative error of SNR * concerning the true value was 0.06% or less, and the coefficient of variation value of SNR * in the demonstration experiment was 0.015 or less, which denoted the accuracy of SNR * . Conclusion: The proposed method realizes SNR measurement even in cases in which only observed images can be obtained and original images cannot be obtained, such as Xray CT images.

To compare the computed tomography (CT) number and the radiation dose between the 64 (group A) and 80-detector row (group B) during lower extremity computed tomography angiography (LE-CTA). We enrolled 144 patients underwent LE-CTA and compared the CT number for the popliteal arteries, radiation dose and the rate of the optimal CT number during the LE-CTA exceeding 200 HU between the two groups. The CT number for the popliteal arteries and mean dose-length product was significantly higher in Group A than in Group B (P < 0.01). The rate of the optimal CT number for the popliteal arteries was 23.6% with Group B scanner and 56.9% with Group A (P < 0.05). The 64-detector row CT was significantly higher in the CT number for the popliteal arteries, radiation dose and rate of the optimal CT number during the LE-CTA than the 80-detector row. Depiction ability did not improve by using a high CT scanner with a wider detector during LE-CTA.