The elimination of the linear artifacts by the metal restorations in the three dimensional computed tomographic images using the personal computer and software / 대한구강악안면방사선학회지

PURPOSE: The purpose of this study is to evaluate the effectiveness and usefulness of newly developed personal computer-based software to eliminate the linear artifacts by the metal restorations. MATERIALS AND METHODS: A 3D CT image was conventionally reconstructed using ADVANTAGE WINDOWS 2.0 3D Analysis software (GE Medical System, Milwaukee, USA) and eliminated the linear artifacts manually. Next, a 3D CT image was reconstructed using V-works 4.0 TM (Cybermed Inc., Seoul, Korea) and the linear artifacts eliminated manually in the axial images by a skillful operator using a personal computer. A 3D CT image was reconstructed using V-works 4.0 TM (Cybermed Inc., Seoul, Korea) and the linear artifacts were removed using a simplified algorithm program to eliminate the linear artifacts automatically in the axial images using a personal computer, abbreviating the manual editing procedure. Finally, the automatically edited reconstructed 3D images were compared to the manually edited images. RESULTS AND CONCLUSION: We effectively eliminated the linear artifacts automatically by this algorithm, not by the manual editing procedures, in some degree. But programs based on more complicated and accurate algorithms may lead to a nearly flawless elimination of these linear artifacts automatically.

Reproducibilities of cephalometric measurements of three-dimensional CT images reconstructed in the personal computer / 대한구강악안면방사선학회지

PURPOSE: The purpose of this study was to report the reproducibility of intra-observer and inter-observer consistency of cephalometric measurements using three-dimensional (3D) computed tomography (CT), and the degree of difference of the cephalometric measurements. MATERIALS AND METHODS: CT images of 16 adult patients with normal class I occlusion were sent to personal computer and reconstructed into 3D images using V-Works 3.5 TM (Cybermed Inc., Seoul, Korea). With the internal program of V-Works 3.5 TM, 12 landmarks on regular cephalograms were transformed into 21 analytic categories and measured by 2 observers and in addition, one of the observers repeated their measurements. Intra-observer difference was calculated using paired t-test, and inter-observer by two sample test. RESULTS: There were significant differences in the intra-observer measurements (p< 0.05) in four of the categories which included ANS-Me, ANS-PNS, Cdl-Go (Lt), GoL-GoR, but with the exception of Cdl-Go (Lt), ZmL-ZmR, Zyo-Zyo, the average differences were within 2 mm of each other. The inter-observer observations also showed significant differences in the measurements of the ZmL-ZmR and Zyo-Zyo categories (p< 0.05). With the exception of the Cdl-Me (Rt), ZmL-ZmR, Zyo-Zyo categories, the average differences between the two observers were within 2 mm, but the ZmL-ZmR and Zyo-Zyo values differed greatly with values of 8.10 and 19.8 mm respectively. CONCLUSION: In general, 3D CT images showed greater accuracy and reproducibility, with the exception of suture areas such as Zm and Zyo, than regular cephalograms in orthodontic measurements, showing differences of less than 2 mm, therefore 3D CT images can be useful in cephalometric measurements and treatment planning.

A Case of de novo Interstitial Deletion of 17 Chromosome

This is the first reported case of a unique interstitial deletion involving the long arm of chromosome 17 in a Korean male infant born to parents with normal karyotype. The patient presented with multiple congenital malformations suggestive of chromosomal anomaly including round face, upslanted palpebral fissure, hypertelorism, posteriorly rotated low set ear, micrognathia, microcephaly, finger- like thumb, bilateral hearing loss, cryptorchidism, and severe developmental delay found upon outpatient follow-ups. A table of comparison is shown in between our case with previously reported 3 cases by Park, et al.(1992), Dallapiccola, et al.(1993), and Khalifa, et al.(1993).