• Imaging Science in Dentistry
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• v.47 no.4
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• pp.233-239
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• 2017

Purpose: This study was performed to quantify the repeat rate of imaging acquisitions based on different clinical examinations, and to assess the prevalence of error types in intraoral bitewing and periapical imaging using a digital complementary metal-oxide-semiconductor(CMOS) intraoral sensor. Materials and Methods: A total of 8,030 intraoral images were retrospectively collected from 3 groups of undergraduate clinical dental students. The type of examination, stage of the procedure, and reasons for repetition were analysed and recorded. The repeat rate was calculated as the total number of repeated images divided by the total number of examinations. The weighted Cohen's kappa for inter- and intra-observer agreement was used after calibration and prior to image analysis. Results: The overall repeat rate on intraoral periapical images was 34.4%. A total of 1,978 repeated periapical images were from endodontic assessment, which included working length estimation (WLE), trial gutta-percha (tGP), obturation, and removal of gutta-percha (rGP). In the endodontic imaging, the highest repeat rate was from WLE (51.9%) followed by tGP (48.5%), obturation (42.2%), and rGP (35.6%). In bitewing images, the repeat rate was 15.1% and poor angulation was identified as the most common cause of error. A substantial level of intra- and inter-observer agreement was achieved. Conclusion: The repeat rates in this study were relatively high, especially for certain clinical procedures, warranting training in optimization techniques and radiation protection. Repeat analysis should be performed from time to time to enhance quality assurance and hence deliver high-quality health services to patients

• Clinical and Experimental Pediatrics
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• v.57 no.6
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• pp.264-270
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• 2014

Purpose: Acute necrotizing encephalopathy (ANE) is a fulminant disease of the brain characterized by bilateral thalamic lesions, and is prevalent among children in East Asia. The prognosis of ANE is usually poor with a high mortality rate and neurological sequelae. This study aimed to delineate the clinical characteristics and prognostic factors of ANE. Methods: We retrospectively analyzed clinical data of 399 pediatric patients with encephalitis who were admitted to Samsung Medical Center from December 1998 to March 2011. We enrolled ten patients (11 cases) with ANE and analyzed their demographic, clinical, and neuroimaging data. The location and extent of the brain regions were checked based on fluid-attenuated inversion recovery, T1-, and T2-weighted imaging findings; the presence of contrast enhancement, restricted diffusion, and hemorrhage. Results: Ten patients were identified, including one patient with two episodes. The median age of onset was 1.5 years (0.4-8.4 years). The mortality rate was 40%, and only 30% of patients survived without neurological sequelae. The definite involvement of the brainstem on brain magnetic resonance imaging was significantly correlated with mortality (P =0.04). Conclusion: Broad and extensive brainstem involvement suggested the fulminant course of ANE. Early diagnosis of ANE before brainstem involvement, through careful identification of symptoms of brain dysfunction, may be the best way to achieve better neurological outcomes.

• Archives of Plastic Surgery
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• v.40 no.4
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• pp.392-396
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• 2013

Background The typical clinical symptoms of glomus tumors are pain, tenderness, and sensitivity to temperature change, and the presence of these clinical findings is helpful in diagnosis. However, the tumors often pose diagnostic difficulty because of variations in presentation and the nonspecific symptoms of glomus tumors. To the best of our knowledge, few studies have reported on the usefulness of magnetic resonance imaging (MRI) in diagnosing glomus tumors in patients with unspecific symptoms. Methods The inclusion criteria of this study were: having undergone surgery for subungual glomus tumor of the hand, histopathologic confirmation of glomus tumor, and having undergone preoperative MRI. Twenty-one patients were enrolled. The characteristics of the tumors and the presenting symptoms including pain, tenderness, and sensitivity to temperature change were retrospectively reviewed. Results Five out of 21 patients (23%) did not show the typical glomus tumor symptom triad because they did not complain of pain provoked by coldness. Nevertheless, preoperative MRI showed well-defined small soft-tissue lesions on T1- and T2-weighted images, which are typical findings of glomus tumors. The tumors were completely resected and confirmed as glomus tumor histopathologically. Conclusions Early occult lesions of glomus tumor in the hand may not be revealed by physical examination because of their barely detectable symptoms. Moreover, subungual lesions may be particularly difficult to evaluate on physical examination. Our cases showed that MRI offers excellent diagnostic information in clinically undiagnosed or misdiagnosed patients. Preoperative MRI can accurately define the character and extent of glomus tumor, even though it is impalpable and invisible.

• Journal of Veterinary Clinics
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• v.24 no.1
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• pp.26-28
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• 2007

An 11-year-old castrated male, Shih-tzu dog was admitted for progressive weight-bearing lameness and mass on the right hindlimb. Radiography and ultrasonography revealed a large well-marginated multinodular mass with mixed echogenicity. On T1 and T2-weighted magnetic resonance imaging (MRI), the mass has a heterogenous signal intensity similar to or higher than muscle. The masses were extended to the pelvic cavi쇼 through obturator foramen and displaced the rectum dorsally. It was diagnosed as synovial sarcoma which was composed with mesenchymal and epithelial elements on histopathological findings of the multifocal biopsied specimen. MRI was helpful to determine the definitive margin for surgical resection of the mass. The mass was recurred at the 6th month after surgery. On the 10th month, the patient was euthanasiuzed by owner's request.

• Clinical and Experimental Pediatrics
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• v.49 no.2
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• pp.212-216
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• 2006

Neurocutaneous melanosis is a rare congenital syndrome characterized by the presence of large or multiple congenital melanocytic nevi and benign pigment cell tumors of the leptomeninges. Neurocutaneous melanosis is thought to represent an error in the morphogenesis of embryonal neuroectoderm. We experienced a neonate who presented with giant, dark colored pigmented nevi covering chest, abdomen, neck and arms, with satellite lesions. Magnetic resonance image showed a nodular hyperintense lesion in the amygdala of the right temporal lobe, and T1-weighted images showed hyperintensities in the adjacent leptomeninges. We report a rare case of neurocutaneous melanosis with a brief review of related literature.

• Journal of Veterinary Clinics
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• v.38 no.1
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• pp.45-48
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• 2021

A 6-year-old, 26 kg spayed female Great Dane presented with back pain and hindlimb paresis. On neurological examination, severe pain was detected on the lumbosacral joint displaying nerve-root signature. The animal presented with lower motor neuron paresis with normal deep pain perception. Radiographic examination revealed narrowing of the lumbosacral joint disc space with endplate destructive lysis. Magnetic resonance imaging of the lumbosacral joint revealed a cauda equina compression, especially on the left. On T2 and T1-weighted images, a mass sized 1 × 1 cm was identified laterally to the left of the lumbosacral joint with hyperintense signal. The lumbosacral joint was stabilized by applying the dorsal distraction fixation-fusion technique and dorsal laminectomy. The soft tissue mass was removed, and a bacterial culture was performed. Coagulase-negative Staphylococcus spp. were detected and discospondylitis was treated with clindamycin for 6 weeks. The patient showed clinical improvement without pain and hindlimb paresis until 6 months follow-up postoperatively.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.5
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• pp.544-555
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• 2002

The aim of this study is to develop the $^1H$-MRS data postprocessing software for both single-voxel and multi-voxel technique, which plays and important role as a diagnostic tool in clinical field. This software is based on graphical user interface(GUI) under windows operating system of personal computer(PC). In case of single-voxel MRS, both of raw data in time-domain and spectrum data in frequency-domain are simultaneously displayed in a screen. Several functions such as DC correction, zero filling, line broadening, Lorentz-Gauss filtering and phase correction, etc. are included to increase the quality of spectrum data. In case of multi-voxel analysis, spectroscopic image reconstructed by 3-D FFT was displayed as a spectral grid and overlapped over previously obtained T1- or T2-weighted image for the spectra to be spatially registered with the image. The analysis of MRS peaks were performed by obtaining the ratio of peak area. In single-voxel method, statistically processed peak-area ratios of MRS data obtained from normal human brain are presented. Using multi-voxel method, MR spectroscopic image and metabolite image acquired from brain tumor are demonstrated.

• Journal of Veterinary Clinics
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• v.27 no.5
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• pp.588-592
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• 2010

A 15-year-old neutered male Yorkshire terrier was presented with a gait disorder of the pelvic limbs. For differential diagnosis of neural disease, magnetic resonance imaging (MRI) and computed tomography (CT) scan were performed. CT showed bone defect in the 4th lumbar vertebra and adjacent soft tissue mass. MRI revealed a mass in left side of the 4th lumbar vertebra. The mass was uniformly enhanced on contrast-enhanced T1-weighted imaging (T1W1). Excision of the mass alleviated back pain. Vertebral osteosarcoma was identified by the histopathological examination. Therefore, CT and MRI were helpful to diagnose vertebral osteosarcoma in the dog and to plan surgical excision of the mass.

• Journal of the Korean Arthroscopy Society
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• v.16 no.2
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• pp.140-146
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• 2012

Purpose: The objective of this study was to assess the clinical outcome of arthroscopic release of the extensor carpi radialis brevis (ECRB) tendon in chronic recalcitrant lateral epicondylitis and tried to determine any prognostic factors. Materials and Methods: A retrospective review of 24 patients with lateral epicondylitis treated by arthroscopic ECRB release was performed. Outcome measures included a patient self rating and visual analog scale (VAS). Functional evaluation was made with Quick-disabilities of the arm, shoulder and hand (DASH) score system to identify preoperative factors that might be associated with the outcomes. Results: Twenty one (88%) elbows received benefit from the procedure. A mean preoperative VAS pain score and the mean Quick-DASH were significantly improved at final follow up. Age, sex, dominant arm and duration of symptom, presence of capsular tear or calcification did not correlate significantly with the clinical outcome. Three of four patients without T2-weighted high signal focus of the ECRB origin on preoperative magnetic resonance imaging (MRI) showed higher Quick-DASH score. Conclusion: Arthroscopic release of the ECRB is an effective option for chronic recalcitrant lateral epicondylitis. Lack of high signal focus on preoperative MRI is significantly associated with a poor surgical outcome and a considerable factor for the proper surgical indication.

• Investigative Magnetic Resonance Imaging
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• v.22 no.2
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• pp.94-101
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• 2018

Purpose: To determine the value of the appearance of the high signal intensity halo sign for detecting carotid intraplaque hemorrhage (IPH) on maximum intensity projection (MIP) of time-of-flight (TOF) MR angiography (MRA), based on high signal intensity on magnetization-prepared rapid acquisition with gradient-echo (MPRAGE) sequencing. Materials and Methods: A total of 78 carotid arteries in 65 patients with magnetization-prepared rapid acquisition gradient-echo (MPRAGE) positive on carotid plaque MR imaging were included in this study. High-resolution MR imaging was performed on a 3.0-T scanner prior to carotid endarterectomy or carotid artery stenting. Fast spin-echo T1- and T2-weighted axial imaging, TOF, and MPRAGE sequences were obtained. Carotid plaques with high signal intensity on MPRAGE > 200% that of adjacent muscle on at least two consecutive slices were defined as showing IPH. Halo sign of high signal intensity around the carotid artery was found on MIP from TOF MRA. Continuous and categorical variables were compared among groups using the Mann-Whitney test and Fisher's exact tests. Results: Of these 78 carotid arteries, 53 appeared as a halo sign on the TOF MRA. The total IPH volume of patients with a positive halo sign was significantly higher than that of patients without a halo sign ($75.0{\pm}86.8$ vs. $16.3{\pm}18.2$, P = 0.001). The maximum IPH axial wall area in patients with a positive halo sign was significantly higher than that of patients without a halo sign ($11.3{\pm}9.9$ vs. $3.7{\pm}3.6$, P = 0.000). Conclusion: High signal intensity halo of IPH on MIP of TOF MRA is associated with total volume and maximal axial wall area of IPH.