Feasibility of Obtaining Quantitative 3-Dimensional Information Using Conventional Endoscope: A Pilot Study

BACKGROUND/AIMS: Three-dimensional (3D) imaging is gaining popularity and has been partly adopted in laparoscopic surgery or robotic surgery but has not been applied to gastrointestinal endoscopy. As a first step, we conducted an experiment to evaluate whether images obtained by conventional gastrointestinal endoscopy could be used to acquire quantitative 3D information. METHODS: Two endoscopes (GIF-H260) were used in a Borrmann type I tumor model made of clay. The endoscopes were calibrated by correcting the barrel distortion and perspective distortion. Obtained images were converted to gray-level image, and the characteristics of the images were obtained by edge detection. Finally, data on 3D parameters were measured by using epipolar geometry, two view geometry, and pinhole camera model. RESULTS: The focal length (f) of endoscope at 30 mm was 258.49 pixels. Two endoscopes were fixed at predetermined distance, 12 mm (d12). After matching and calculating disparity (v2-v1), which was 106 pixels, the calculated length between the camera and object (L) was 29.26 mm. The height of the object projected onto the image (h) was then applied to the pinhole camera model, and the result of H (height and width) was 38.21 mm and 41.72 mm, respectively. Measurements were conducted from 2 different locations. The measurement errors ranged from 2.98% to 7.00% with the current Borrmann type I tumor model. CONCLUSIONS: It was feasible to obtain parameters necessary for 3D analysis and to apply the data to epipolar geometry with conventional gastrointestinal endoscope to calculate the size of an object.

Evaluation of Airway Obstruction at Soft Palate Level in Male Patients with Obstructive Sleep Apnea/Hypopnea Syndrome: Dynamic 3-Dimensional CT Imaging of Upper Airway / 华中科技大学学报（医学）（英德文版）

This study examined the dynamic characteristics of upper airway collapse at soft palate level in patients with obstructive sleep apnea/hypopnea syndrome (OSAHS) by using dynamic 3-Dimensional (3-D) CT imaging.A total of 41 male patients who presented with 2 of the following symptoms,i.e.,daytime sleepiness and fatigue,frequent snoring,and apnea with witness,were diagnosed as having OSAHS.They underwent full-night polysomnography and then dynamic 3-D CT imaging of the upper airway during quiet breathing and in Muller's maneuver.The soft palate length (SPL),the minimal cross-sectional area of the retropalatal region (mXSA-RP),and the vertical distance from the hard palate to the upper posterior part of the hyoid (hhL) were compared between the two breathing states.These parameters,together with hard palate length (HPL),were also compared between mild/moderate and severe OSAHS groups.Association of these parameters with the severity of OSAHS [as reflected by apnea hypopnea index (AHI) and the lowest saturation of blood oxygen (LSaO2)] was examined.The results showed that 31 patients had severe OSAHS,and 10 mild/moderate OSAHS.All the patients had airway obstruction at soft palate level.mXSA-RP was significantly decreased and SPL remarkably increased during Muller's maneuver as compared with the quiet breathing state.There were no significant differences in these airway parameters (except the position of the hyoid bone) between severe and mild/moderate OSAHS groups.And no significant correlation between these airway parameters and the severity of OSAHS was found.The position of hyoid was lower in the severe OSAHS group than in the mild/moderate OSAHS group.The patients in group with body mass index (BMI)≥26 had higher collapse ratio of mXSA-RP,greater neck circumference and smaller mXSA-RP in the Muller's maneuver than those in group with BMI＜26 (P＜0.05 for all).It was concluded that dynamic 3-D CT imaging could dynamically show the upper airway changes at soft palate level in OSAHS patients.All the OSAHS patients had airway obstruction of various degrees at soft palate level.But no correlation was observed between the airway change at soft palate level and the severity of OSAHS.The patients in group with BMI≥26 were more likely to develop airway obstruction at soft palate level than those with BMI＜26.

The Usefulness of Three Dimensional Reconstruction Imaging using Spiral CT: an Experience in the Bilateral Wilms` Tumor Surgery / 대한비뇨기과학회지

Conventional angiography has been used to identify detailed vascular anatomy for surgery in which parenchymal salvage should be necessary. Recently, we experienced a case in which 3-dimensional CT was very helpful in salvaging the part of the kidney. A 2 year-old girl was diagnosed as bilateral Wilms` tumor. Conventional CT scan showed right huge mass and left upper pole mass of the kidney. The patient was planned to have neoadjuvant chemotherapy. Spiral CT scan with three-dimensional reconstruction was performed after 3-month chemotherapy and detailed anatomical information regarding vessels, tumor mass and normal parenchyma was obtained. Based on these anatomical information, right radical nephrectomy and left partial nephrectomy was successfully performed. Surgical findings was quite similar to that obtained by preoperative 3-dimensional CT images. Three-dimensional reconstruction of spiral CT imaging is considered to be useful in the evaluation of surgical anatomy in kidney-saving surgery preoperatively.

A Study on the Shape of the Proximal Femur for Designing Korean-type of the Femoral Stem / 대한정형외과학회잡지

Avascular necrosis of the femoral head is the most common disease for which total hip arthroplasty is being performed in Korea. In order to develop a femoral stem having a proper fit to Korean femur, it is essential to study the change in the shape of the proximal endosteal canal of the femur resulting from disuse caused by pain avascular necrosis of the femoral head. The size and shape of the proximal femur were measured with 3-dimensional images reconstructed from the CT data of 116 femurs in 58 patients who had suffered from avascular necrosis of the femoral head. Among them, there were 30 patients who had suffered from unilateral involvement of avascular necrosis of the femoral head. The comparative study was made on the shape of the proximal endosteal canal of the femur between the normal and the diseased femurs. The shape of proximal endosteal canal of femur in avascular necrosis didn't show statistically significant difference from that of the normal femur. Therefore, the femoral stem designed from the data of normal femurs can be usually applied to the avascular necrosis without problem in obtaining the maximal fit between the stem and the endosteal canal. The canal flare index was greater and the proportion of champagne-flute type was higher in Korean than in Westerner. The shape of the endosteal canal of isthmus was nearly circular in Korean in contrast to anteroposteriorly ovoid in Westerner. The distribution of sagittal canal flare index which was newly defined in this study was entirely different from that of preexisting canal flare index in coronal plane. It will be necessary to study further in the future.