• Journal of Korean Neurosurgical Society
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• 제49권2호
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• pp.107-111
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• 2011

Objective : The aim of this study was to evaluate the utility of volume-rendered helical computerized tomography (CT) angiography focusing tracheostomy tube and innominate artery for prevention of tracheoinnominate artery fistula. Methods : The authors retrospectively analyzed 22 patients with tracheostomy who had checked CT angiography. To evaluate the relationship between tracheostomy tube and innominate artery, we divided into three categories. First proximal tube position based on cervical vertebra, named "tracheostomy tube departure level (TTDL)". Second, distal tube position and course of innominate artery, named "tracheostomy tube-innominate artery configuration (TTIC)". Third, the gap between the tube and innominate artery, named "tracheostomy tube to innominate artery gap (TTIG)". The TTDL/TTIC and TTIG are based on 3-dimensional (3D) reconstruction around tracheostomy and enhanced axial slices of upper chest, respectively. Results : First, mean TTDL was $6.8{\pm}0.6$. Five cases (23%) were lower than C7 vertebra. Second, TTIC were remote to innominate artery (2 cases; 9.1 %), matched with it (14 cases; 63.6%) or crossed it (6 cases; 27.3%). Only 9% of cases were definitely free from innominate artery injury. Third, average TTIG was $4.3{\pm}4.6$ mm. Surprisingly, in 6 cases (27.3%), innominate artery, trachea wall and tracheostomy tube were tightly attached all together, thus have much higher probability of erosion. Conclusion : If low TTDL, match or crossing type TTIC with reverse-L shaped innominate artery, small trachea and thin TTIG are accompanied all together, we may seriously consider early plugging and tube removal.

• Nuclear Engineering and Technology
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• 제47권4호
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• pp.472-478
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• 2015

The patient dose incurred from diagnostic procedures during advanced radiotherapy has become an important issue. Many researchers in medical physics are using computational simulations to calculate complex parameters in experiments. However, extended computation times make it difficult for personal computers to run the conventional Monte Carlo method to simulate radiological images with high-flux photons such as images produced by computed tomography (CT). To minimize the computation time without degrading imaging quality, we applied a deterministic adaptation to the Monte Carlo calculation and verified its effectiveness by simulating CT image reconstruction for an image evaluation phantom (Catphan; Phantom Laboratory, New York NY, USA) and a human-like voxel phantom (KTMAN-2) (Los Alamos National Laboratory, Los Alamos, NM, USA). For the deterministic adaptation, the relationship between iteration numbers and the simulations was estimated and the option to simulate scattered radiation was evaluated. The processing times of simulations using the adaptive method were at least 500 times faster than those using a conventional statistical process. In addition, compared with the conventional statistical method, the adaptive method provided images that were more similar to the experimental images, which proved that the adaptive method was highly effective for a simulation that requires a large number of iterations-assuming no radiation scattering in the vicinity of detectors minimized artifacts in the reconstructed image.

• Clinics in Shoulder and Elbow
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• 제21권3호
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• pp.113-119
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• 2018

Background: This study was undertaken to evaluate the positional relationship between planes of the glenoid component (the scapular plane and the perpendicular plane to the glenoid) and its surrounding structures. Methods: Computed tomography (CT) images of both shoulders of 100 patients were evaluated using the 3-dimensional CT reconstruction program ($Aquarius^{(R)}$; TeraRecon). We determined the most lateral scapular bony structure of the scapular plane and measured the shortest distance between the anterolateral corner of the acromion and the scapular plane. The distance between the scapular plane and the midpoint of the line connecting the posterolateral corner of acromion and the anterior tip of the coracoid process (fulcrum axis) was also evaluated. The perpendicular plane was then adjusted to the glenoid and the same values were re-assessed. Results: The acromion was the most lateral scapular structure of scapular plane and perpendicular plane to the glenoid. The average distance from the anterolateral corner of the acromion to the scapular plane was $10.44{\pm}5.11mm$, and to the plane perpendicular to the glenoid was $9.55{\pm}5.13mm$. The midpoint of fulcrum axis was positioned towards the acromion and was measured at $3.90{\pm}3.21mm$ from the scapular plane and at $3.84{\pm}3.17mm$ from the perpendicular plane to the glenoid. Conclusions: Our data indicates that the relationship between the perpendicular plane to the glenoid plane and its surrounding structures is reliable and can be used as guidelines during glenoid component insertion (level of evidence: Level IV, case series, treatment study).

• Archives of Plastic Surgery
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• 제39권5호
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• pp.528-533
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• 2012

Background Rectus abdominis muscle and abdominal subcutaneous fat tissue are useful for reconstruction of the chest wall, and abdominal, vaginal, and perianal defects. Thus, preoperative evaluation of rectus abdominis muscle and abdominal subcutaneous fat tissue is important. This is a retrospective study that measured the thickness of rectus abdominis muscle and abdominal subcutaneous fat tissue using computed tomography (CT) and analyzed the correlation with the patients' age, gestational history, history of laparotomy, and body mass index (BMI). Methods A total of 545 adult women were studied. Rectus abdominis muscle and abdominal subcutaneous fat thicknesses were measured with abdominopelvic CT. The results were analyzed to determine if the thickness of the rectus abdominis muscle or subcutaneous fat tissue was significantly correlated with age, number of pregnancies, history of laparotomy, and BMI. Results Rectus abdominis muscle thicknesses were 9.58 mm (right) and 9.73 mm (left) at the xiphoid level and 10.26 mm (right) and 10.26 mm (left) at the umbilicus level. Subcutaneous fat thicknesses were 24.31 mm (right) and 23.39 mm (left). Rectus abdominismuscle thickness decreased with age and pregnancy. History of laparotomy had a significant negative correlation with rectus abdominis muscle thickness at the xiphoid level. Abdominal subcutaneous fat thickness had no correlation with age, number of pregnancies, or history of laparotomy. Conclusions Age, gestational history, and history of laparotomy influenced rectus abdominis muscle thickness but did not influence abdominal subcutaneous fat thickness. These results are clinically valuable for planning a rectus abdominis muscle flap and safe elevation of muscle flap.

• Restorative Dentistry and Endodontics
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• 제29권4호
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• pp.378-385
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• 2004

The purpose of this study was to compare the effects of preparation with GT files and profiles .04 in shaping of root canals and reconstruct the three-dimensional root canal system using micro computed tomography 40 canals of the extracted human mandibular molars were used, and randomly distributed into two experimental groups. In group 1. canals were prepared by GT files. In group 2, Profiles .04. were used. Apical preparation size was #30. For each tooth pre and post operative cross-sectional images were obtained by the micro CT at 50 micron intervals. Pre and post operative cross-sectional images of 1, 2, 3, 5, and 8mm from the apex were compared. For each section. canal area and centering ratio were determined. For each tooth pre- and post-operative root canal volume from the furcation to the apex of the roots was calculated by three-dimensional image software. Following results were obtained: 1. At 8mm from the apex, area of dentin removed by GT rotary file was significantly larger than that by Profile .04. And at the other levels there was not a significant difference. 2. There was a trend for GT rotary file to remain more centered in the canals than Profile .04 at all levels. But at 3mm level. there was a statistically significant difference. 3. In root canal volume increments after instrumentation, there was no significant difference between two groups.

• Archives of Plastic Surgery
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• 제39권4호
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• pp.333-337
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• 2012

Background Patients who have undergone enucleation during infancy due to retinoblastoma can develop microorbitalism due to the decreased growth stimulation from the eyeball and the surrounding soft tissues. Anatomically, the orbit consist of parts of the frontal bone superiorly, the maxilla inferiorly, the ethmoid bone medially, and the zygoma laterally. Considering the possibility of surgically expanding the orbit using tripod osteotomy, in this study we conducted tripod osteotomy on adult patients with microorbitalism of retinoblastoma. Methods Tripod osteotomy was conducted to expand the orbital volume in adult patients with microorbitalism due to enucleation in infancy for retinoblastoma. The orbital volume was measured using the Aquarius Workstation ver. 4.3.6 and the orbit width was measured with preoperative and postoperative 3-dimensional facial bone computed tomography (CT) imaging. Preoperative and postoperative photographs were used to visualize the difference produced by the surgery. Results The orbital volume of the affected side was 10.3 $cm^3$ before and 12.5 $cm^3$ after the surgery, showing an average increase in volume of 2.2 $cm^3$ (21.4%). The increase in the obital width was confirmed by the preoperative and postoperative 3-dimensional facial CT images and aesthetic improvement was observed by the preoperative and postoperative photographs. Conclusions Tripod osteotomy, which realigns the orbital bone, zygoma, and maxilla, is used to correct posttraumatic malunion as well as non-traumatic congenital abnormalities such as that seen in facial cleft. We applied this procedure in microorbitalism secondary to enucleation for retinoblastoma to allow orbital expansion and correct asymmetry.

• Archives of Plastic Surgery
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• 제44권6호
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• pp.496-501
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• 2017

Background Various surgical methods for repairing medial orbital wall fractures have been introduced. The conventional technique requires total separation of the displaced orbital bones from the orbital soft tissues. However, subperiosteal dissection around the fracture can cause additional damage. The aim of the present study is to introduce a method of reconstructing medial orbital wall fractures without subperiosteal dissection named the "push-out" technique. Methods Six patients with post-traumatic enophthalmos resulting from an old medial orbital wall fracture and 10 patients with an acute medial orbital wall fracture were included. All were treated with the push-out technique. Postoperative computed tomography (CT) was performed to assess the correct positioning of the implants. The Hertel scale and a comparison between preoperative and postoperative orbital volume were used to assess the surgical results. Results Restoration of the normal orbital cavity shape was confirmed by examining the postoperative CT scans. In the old fracture group, the median orbital volume of the fractured side was $29.22cm^3$ preoperatively, and significantly improved postoperatively to a value of $25.13cm^3$. In the acute fracture group, the median orbital volume of the fractured side was $28.73cm^3$ preoperatively, and significantly improved postoperatively to a value of $24.90cm^3$. Differences on the Hertel scale also improved, from 2.13 mm preoperatively to 0.25 mm postoperatively in the old fracture group and from 1.67 mm preoperatively to 0.33 mm postoperatively in the acute fracture group. Conclusions The push-out technique can be considered a good alternative choice for old medial orbital wall fractures with posttraumatic enophthalmos, acute medial orbital wall fractures including large fractured bone segments, and single-hinged greenstick fractures.

• Clinics in Shoulder and Elbow
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• 제2권2호
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• pp.151-156
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• 1999

Purpose : Average humeral head retroversion was showed significant wide range from literatures based on variable measuring technique, We performed computed tomography(CT) study in an effort to define the specific anatomy relationships and evaluate their use. Materials and Methods : Two hundreds shoulders and distal humeri CT scan with no known pathology were examined. The study population was divided to 10 groups by gender and age (from third to seventh decade). The number of each group was twenty. Retroversion of proximal humerus and glenoid were measured using the lines that were connected the central axis of humeral head, central points of the humeral epicondyles paralleling to the trochlea, paralled to the glenoid surface, midpoint between the transverse glenoid diameter and medial edge of the scapular. We also measured the bicipital groove distance from the humeral central axis and scapulothoracic angle. Results: Retroversion of proximal humerus was highly variable, ranging in this study from 13 to 58 degrees(mean 28.73) These values correlated with sex, not age, height or hand dominance. Glenoid retroversion at the inferior sections showed average 1.3 degree, did not signigicant differences. The central axis was an average of l0mm(5-15mm) posterior to the posterior margin of the bicipital groove. Scapulothoracic angle was average 43 degrees(25-53 degrees) Conclusion: Anatomical reconstruction of retroversion angle should be individualized and bicipital groove could be useful as landmark for the lateral fin of the prosthesis to be positioned an average of 10mm posteriorly.

• The Journal of the Korean dental association
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• 제54권10호
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• pp.811-819
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• 2016

Panfacial fracture is extremely difficult to manage facial injuries but concomitant injuries and severe complications including facial esthetic and functional problems can make it harder. Thorough evaluation and closed co-work with other specialists is needed when reduction and fixation cannot be achieved quickly. Emergency bony support and soft tissue key suture provide the patients with airway integrity, hard and soft tissue vitality. A systemic treatment plan must be made by 3D CT image. This plan include airway management for surgery, sequence of reduction and fixation, approach method, soft tissue resuspension and reconstruction of lost tissue like inferior orbital wall, zygomaic buttress and soft tissue. From known to unknown structures, accurate reduction and fixation will provide proper occlusion, facial projection, width, hight and function. Consideration about facial retaining ligaments must be given to prevent soft tissue sagging.

• Imaging Science in Dentistry
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• 제40권4호
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• pp.171-178
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• 2010

Purpose : The purpose of this study is to develop a surgical stent for dental implant procedure that can be easily applied and affordable by using cone beam computerized tomography (CBCT). Materials and Methods : Aluminum, Teflon-PFA (perfluoroalkoxy), and acetal (polyoxymethylene plastic) were selected as materials for the surgical stent. Among these three materials, the appropriate material was chosen using the CBCT images. The surgical stent, which could be easily placed into an oral cavity, was designed with chosen material. CBCT images of the new surgical stent on mandible were obtained using Alphard-3030 dental CT system (Asahi Roentgen Co., Ltd., Kyoto, Japan). The point of insertion was prescribed on the surgical stent with the multiplanar reconstruction software of OnDemand3D (CyberMed Inc., Seoul, Korea). Guide holes were made at the point of insertion on the surgical stent using newly designed guide jig. CBCT scans was taken for the second time to verify the accuracy of the newly designed surgical stent. Results : Teflon-PFA showed radiologically excellent image characteristics for the surgical stent. High accuracy and reproducibility of implantation were confirmed with the surgical stent. Conclusion : The newly designed surgical stent can lead to the accurate implantation and achieve the clinically predictable result.