Pain and pain management have long been items of central concern in dentistry. Although they are given little attention in orthodontics, virtually every patient wearing orthodontic appliances experiences and complains of some extent of pain, and someones have suffered from severe throbbing pain. A form of stimulation-produced analgesia, Transcutaneous Electrical Nerve Stimulation (TENS) is a non-invasive, non-pharmacologic pain control techniques. The clinical application of TENS to orthodontic patients may lead to better patient compliance. And I want to discuss some basic knowledge of this TENS.
Analgesia ; Dentistry ; Humans ; Orthodontic Appliances ; Orthodontics ; Pain Management ; Patient Compliance ; Transcutaneous Electric Nerve Stimulation*

No abstract available.
Paget Disease, Extramammary*

OBJECTIVES: A saccular cyst is defined as a dilated saccule of the larynx, filled with mucus, and is located between the false vocal cords and the thyroid cartilage. Although this uncommon laryngeal condition is benign in nature, it could lead to dyspnea, stridor, and airway obstruction, depending on its size and location. Furthermore, some saccular cysts have been associated with laryngeal carcinoma. This study aimed to characterize this rather uncommon laryngeal condition to aid in determining the proper management of this pathology. METHODS: Medical records were retrospectively reviewed of all patients with saccular cysts diagnosed and treated between 2006 and 2017 at a tertiary otolaryngologic care center. RESULTS: Seven patients with saccular cysts were identified (male:female=2:5; mean age, 34.1 years); two were pediatric patients. Surgical intervention was performed in all patients by laryngo-microsurgery using CO2 laser. There was no recurrence after the initial surgical treatment. CONCLUSION: Saccular cysts can be managed endoscopically using CO2 laser, without requiring an external approach. Therefore, an endoscopic approach should be actively considered for an optimal treatment outcome.
Airway Obstruction ; Dyspnea ; Humans ; Larynx ; Lasers, Gas ; Medical Records ; Mucus ; Pathology ; Recurrence ; Respiratory Sounds ; Retrospective Studies ; Saccule and Utricle ; Thyroid Cartilage ; Treatment Outcome ; Vocal Cords

PURPOSE: To compare the effectiveness of the in-phase(IP) sequence and the opposed-phase(OP) sequence in the detection of focal hepatic lesions in the single breath-hold hepatic MR imaging with fast gradient T1-weighted pulse sequences. MATERIALS AND METHODS: If and OP T1-weighted breath-hold imaging was performed using fast gradient echo sequences in 45 patients referred for known focal hepatic lesions, in which 78 lesions were detected. There blind readers independently reviewed the images for lesion detectability. The signal-to-noise ratio(SNR) of the liver, the lesion-to-liver contrast-to-noise ratio(CNR) and the liver-to-spleen CNR were also compared. A consensus was reached by three readers to determine which sequence is better in image quality. RESULTS: On OP images, 61(78%), 61(78%), and 63(89%) lesions were correctly identified for reader 1, 2 and 3, respectively. On IP images, 66(85%), 65(83%), and 65(93%) lesions were detected for each reader, respectively. When two image sets were combined, 71(91%), 69(88%), and 76(97%) lesions respectively were detected for each reader. In cases of hepatocellular carcinoma, liver-to-lesion CNR was greater on the OP images(p<0.05), but in other lesions significant differences was not demonstrated. Liver-to-spleen CNR was higher in OP images(p<0.1), but the SNR of the liver was higher on the If images. CONCLUSION: Use of both If and OP imaging can be helpful to avoid erroneous missing of some focal hepatic lesions.
Carcinoma, Hepatocellular ; Consensus ; Humans ; Liver* ; Magnetic Resonance Imaging*

PURPOSE: It is known that due to both their imaging and pathologic features, the accurate differentiation ofchondrosarcoma from chordoma is difficult. Through an analysis of MR and CT findings, this study aims to determinethe differential points between these two tumors. MATERIALS AND METHODS: In 21 patients, CT and MR imagingstudies of chordoma(n=12) and chondrosarcoma(n=9) at the base of the skull were retrospectively reviewed.Diagnosis had been established by histologic examination of surgically removed specimens. Eleven of the chordomaswere subclassified as 'conventional' and one as 'chondroid'; eight chondrosarcoma were 'conventional' andone was 'myxoid'. Four chordoma patients underwent CT and MR ; in six, only MR was performed ; and in two, onlyCT. Eight chondrosarcoma patients underwent both CT and MR, while in one, only CT was performed. All scans wereretrospectively evaluated for the location(midline/off-midline), direction of extension, margin and shape, bonydestruction and calcification, MR signal intensity and enhancement patterns of the tumors. Degree of calcificationwas graded from I to III. RESULTS: The epicenter of the mass of ten chordomas (83%) was midline, in twochondrosarcomas(22%), this was off-midline. Foci of calcification were observed in three of eleven chordomas(27%),and heavy calcification (grade III) was observed in one. In contrast to these findings, foci of calcificationswere observed in eight of nine chondrosarcomas (89%) and grade III calcification was observed in five. In bothtumors, calcification was coarse. Between the two kinds of tumor, there were no significant difference in MRsignal intensity and enhancement patterns, margin and shape, or direction of extension. CONCLUSIONS: Although MRand CT findings were similar in both types of tumor, location and degree of calcification may be features whichusefully distinguish chordoma from chondrosarcoma.
Chondrosarcoma* ; Chordoma* ; Humans ; Retrospective Studies ; Skull Base* ; Skull*

PURPOSE: To determine relative image qualities and to evaluate their ability to visualize biliary trees and pancreatic ducts, we compared the breath-hold fast spin echo (FSE) and respiratory triggered FSE technique in magnetic resonance cholangiopancreatography (MRCP). MATERIALS AND METHODS: Forty-seven patients with suspected of hepatic disease but no pancreatic or biliary ductal dilatation, as determined by other imaging techniques('group of pathologic pancreatobiliary tree') underwent MRCP. Heavily T2-weighted FSE coronal images were obtained by both breath-hold and respiratory triggered techniques. These two images were 3D-reconstructed using a maximal intensity projection algorithm. Three radiologists scored the image qualities of anatomic structures in each set of image, then directly compared the image quality of the images obtained by the two techniques. RESULTS: For the visualization of common hepatic ducts and common bile dvcts, FSE MRCP images obtained using the respiratory-triggered technique were triggered technique were significantly better than those obtained using the breath-hold technique (P<0.05). Fifty-nine to 88% of breath-hold images of the biliary tree and 63-95% of respiratory triggered images were optimal. For the pancreatic duct, however, 24% of breath-hold images and 15% of respiratory-triggered images provided optimal image quality. In direct comparison, respiratory triggered images were better in 25 cases (52.1%), both images were comparable in 12 cases (25.0%), and in 11 cases (22.9%), breath-hold images were better. These differences were statistically significant (p<0.05). CONCLUSION: For the vizualization of extrahepatic bile ducts, the respiratory triggered FSE sequence was better than the breath-hold sequence; for the evaluation of both a non-dilated and dilated pancreatobiliary system, however, both techniques need further development.
Bile ; Bile Ducts, Extrahepatic ; Biliary Tract ; Cholangiopancreatography, Magnetic Resonance ; Dilatation ; Hepatic Duct, Common ; Humans ; Pancreatic Ducts

No abstract available.
Niemann-Pick Disease, Type A*

PURPOSE: To assess the ability of MR imaging with an endorectal surface coil for the depiction of noraml anatomical structure of prostate and its adjacent organs. MATERIALS AND METHOD: MR imaging using an endorectal surface coil was performed in 23 male patients (age;20-75) to evaluate various prostatic and vasovesicular disorders, i.e., 14 cases of ejaculatory problems, 3 cases of hypogonadism, and 4 cases of prostatic cancers and 2 cases of benign prostatic hyperplasia. MR images were obtained with axial, sagittal and coronal fast spin echo long TR/TE images and axial spin echo short TR/TE images. Field of views was 10--12 cm and scan thickness was3--5 mm. RESULTS: Depiction of normal anatomcial structures was excellent in all cases. On T2WI, zonal anatomy of the prostate and prostatic urethra, urethral crest, and ejaculatory duct were cleary visualized. On T1WI, periprostatic fat plane is more cleary visualized.
Ejaculatory Ducts ; Fluconazole ; Humans ; Hypogonadism ; Magnetic Resonance Imaging* ; Male ; Prostate* ; Prostatic Hyperplasia ; Prostatic Neoplasms ; Urethra

No abstract available.
Peutz-Jeghers Syndrome*

PURPOSE: To compare the usefulness of echo-planar imaging (EPI) and fast spin-echo (FSE) in routine brain MR imaging. MATERIALS AND METHODS: Twenty-five patients with various intracranial diseases were prospectively examined with T2-weighted MR imaging on a 1.5T unit using FSE, spin echo singl-shot EPI (SS-EPI) and multi-shot EPI (MS-EPI) techniques. For qualitative assessment, overall image quality, discrimination between cortical gray-white matter and between basal ganglia-white matter, lesion conspicuity, image distortion and artifacts (motion, ghost, flow, and susceptibility) were all evaluated using a subjective scoring system ranging from 1 to 4 (1 for the worst and 4 for the best). For quantitative assessment, contrast and contrast-to-noise ratio (CNR) were calculated for cortical gray-white matter, basal ganglia-white matter, and lesion-white matter. RESULTS: Overall image quality, discrimination between cortical gray-white matter, basal ganglia-white matter, and lesion-white matter, lesion conspicuity, image distortion and susceptibility artifacts showed the highest value in FSE and the lowest in SS-EPI. Motion artifacts were seen only in FSE, while flow and ghost artifacts were most commonly seen in SS-EPI. Contrast and CNR of anatomical and pathologic structures showed the highest value in FSE, especially for cortical gray-white matter and basal ganglia-white matter . CONCLUSION: With regard to overall image quality, image distortion, susceptibility artifacts, contrast and CNR, EPI is far inferior to FSE. In routine brain MR imaging., the usefulness of EPI techniques would therefore be very limited.
Artifacts ; Brain* ; Discrimination (Psychology) ; Echo-Planar Imaging ; Humans ; Magnetic Resonance Imaging* ; Prospective Studies