• The Korean Journal of Nuclear Medicine
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• v.30 no.4
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• pp.524-531
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• 1996

Purpose : To evaluate the pattern- of skeletal metastases and to classify the pattern of renal uptakes on bone scans in renal cell carcinoma. Materials and Methods : We reviewed the bone scans of 158 patients with RCC established pathologically. In order to identify individual scan lesion as a bone metastasis, we reviewed all available correlative radiological studies, follow-up bone scans, and biopsies for each lesion. The metastatic bone lesions were divided into seven anatomic regions; skull, spine, shoulder girdle, sternum, ribs, pelvis, and long bones of extremities. The individual scan lesions were divided into two groups as the pattern of uptakes, hot and cold lesion. In addition, the contours and uptakes of kidneys with RCC were classified into 6 groups ; normal uptake, photon-deficient lesion, faint up-take with enlargement, uneven uptake with enlargement, lateralization with crescentic shape, and increased uptake. Results : Twenty out of 158(12.7%) patients with RCC at varying stages showed 71 metastatic bone lesions at presentation and on follow- up bone scans. Nearly 80% of all metastatic lesions were in the axial skeleton with predominantly increased uptake of the radioactivity However a considerable number(22.5%) showed cold lesions on bone scan. A half of bone scans revealed abnormal uptake of involved kidney and much more(82.4%) in case of bone metastases. Two common patterns of abnormal renal uptake were photon-deficient lesion (50%) and faint uptake with enlargement(24.3%). In four patients with bone pain or pathologic fracture, bone scans were useful for the serendipitious localization of previously unrecognized primary lesion of RCC as well as for the detection of bone metastases from RCC. Conclusion : The understanding of the pat-terns of skeletal metastases and renal uptakes on bone scans in RCC is important for the useful information about primary lesion(RCC) as well as detection of bone metastases.

• Journal of Electrodiagnosis and Neuromuscular Diseases
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• v.20 no.2
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• pp.106-111
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• 2018

Transcranial magnetic stimulation (TMS) has been a gold standard for investigating central motor pathways in humans. Diffusion tensor imaging with fiber tractography (DTI FT) is known for its usefulness in detecting white matter lesion in vivo. We investigated the clinical usefulness of elucidating the integrity and continuity of corticospinal tract (CST) by combined use of TMS and DTI FT in this study. We report two cases who have presented with left hemiparesis and evaluated by both TMS and DTI FT; 10-year-old boy with Mitochondrial Encephalomyopathy with Lactic Acidosis and Stroke-like episode syndrome and 20-year-old woman with traumatic brain injury. Combined use of TMS and DTI FT successfully led to localize the brain lesion that might cause motor impairment in patients with abnormal signal intensities in MRI. The results of this study suggest that TMS and DTI FT might provide the detailed information between function and anatomy of the CST, complementarily.

• Journal of Internet Computing and Services
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• v.23 no.3
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• pp.35-45
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• 2022

Even in recent years, treatment of first-aid patients is still often delayed due to a shortage of medical resources in marginalized areas. Research on automating the analysis of medical data to solve the problems of inaccessibility for medical services and shortage of medical personnel is ongoing. Computer vision-based medical inspection automation requires a lot of cost in data collection and labeling for training purposes. These problems stand out in the works of classifying lesion that are rare, or pathological features and pathogenesis that are difficult to clearly define visually. Anomaly detection is attracting as a method that can significantly reduce the cost of data collection by adopting an unsupervised learning strategy. In this paper, we propose methods for detecting abnormal images on chest X-RAY images as follows based on existing anomaly detection techniques. (1) Normalize the brightness range of medical images resampled as optimal resolution. (2) Some feature vectors with high representative power are selected in set of patch features extracted as intermediate-level from lesion-free images. (3) Measure the difference from the feature vectors of lesion-free data selected based on the nearest neighbor search algorithm. The proposed system can simultaneously perform anomaly classification and localization for each image. In this paper, the anomaly detection performance of the proposed system for chest X-RAY images of PA projection is measured and presented by detailed conditions. We demonstrate effect of anomaly detection for medical images by showing 0.705 classification AUROC for random subset extracted from the PadChest dataset. The proposed system can be usefully used to improve the clinical diagnosis workflow of medical institutions, and can effectively support early diagnosis in medically poor area.

• Clinical and Experimental Pediatrics
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• v.56 no.10
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• pp.431-438
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• 2013

Magnetoencephalography (MEG) records the magnetic field generated by electrical activity of cortical neurons. The signal is not distorted or attenuated, and it is contactless recording that can be performed comfortably even for longer than an hour. It has excellent and decent temporal resolution, especially when it is combined with the patient's own brain magnetic resonance imaging (magnetic source imaging). Data of MEG and electroencephalography are not mutually exclusive and it is recorded simultaneously and interpreted together. MEG has been shown to be useful in detecting the irritative zone in both lesional and nonlesional epilepsy surgery. It has provided valuable and additive information regarding the lesion that should be resected in epilepsy surgery. Better outcomes in epilepsy surgery were related to the localization of the irritative zone with MEG. The value of MEG in epilepsy surgery is recruiting more patients to epilepsy surgery and providing critical information for surgical planning. MEG cortical mapping is helpful in younger pediatric patients, especially when the epileptogenic zone is close to the eloquent cortex. MEG is also used in both basic and clinical research of epilepsy other than surgery. MEG is a valuable diagnostic modality for diagnosis and treatment, as well as research in epilepsy.

• Tuberculosis and Respiratory Diseases
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• v.48 no.4
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• pp.438-447
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• 2000

Background : Transbronchial lung biopsy (TBLB) is a relatively simple and convenient procedure to obtain lung tissue from a patient with diffuse or localized lesion on chest radiographs, whose disease cannot be diagnosed through routine tests. The authors tried to evaluate the diagnostic value of TBLB, especially, the concordance between CT scan and TBLB with respect to the location of the lesion and diagnostic yield according to tumor-bronchus relationship. Method : We reviewed the medical records, plain chest films, and chest CT scans of 278 patients who underwent TBLB at Kyungpook National University Hospital between January 1996 and June 1998. Results : One hundred and sixteen (41.7 %) patients were diagnosed by TBLB. Diagnostic yield of TBLB of malignant tumors tended to be higher than that of benign diseases (64.7% versus 53.9%, p=0.09). Of primary lung cancers, TBLB was more diagnostic in adenocarcinoma and small-cell carcinoma than other cell types (p<0.01) and, of benign diseases, more diagnostic in tuberculosis than in non-tuberculous diseases (p<0.05). There was no significant difference in the diagnostic rate according to the location of the tumor. The diagnostic rate tended to increase with the size of tumor (p=0.06). The diagnootic rate of TBLB did not differ according to the pattern of lesion in benign diseases. However, in malignant diseases TBLB was more diagnostic in diffuse/multiple nodular lesions than in localized lesions(p<0.05). According to the tumor-bronchus relationship, TBLB was more diagnootic in type I/II groups than in other types. CT scan and TBLB showed a strong correlation with respect to the localization of the lesion (r=0.994, p<0.01). Conclusion : The above results show that TBLB is useful in the diagnosis of lung disease. CT scan and TBLB showed a strong correlation in determining the location of the lesion. Diagnostic yield of TBLB is higher in lesions with 'bronchus sign' (type I and II). TBLB and other diagnootic methods such as transthoracic needle aspiration are expected to complement one another in the diagnosis of lung diseases.

• Journal of Korean Neurosurgical Society
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• v.30 no.1
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• pp.41-46
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• 2001

Objective : The exact position of the lesion during the pallidotomy is critical to obtain the clinical improvement of parkinson's disease without damage to surrounding structure. Ventriculogrphy, CT(computed tomograpy) or MRI(magnetic resonance imaging) have been used to determine the initial coordinates of stereotactic target for pallidotomy. The goal of this study was to determine whether microelectrode recording significantly improves the neurophysiologic localization of the target obtained from MRI. Methods : Twenty patients were studied. They underwent a unilateral pallidotomy. Leksell frame was applied and T1 axial images parallel to the AC-PC(anterior commissure-posterior commissure) plane using a 1.5 Tesla MRI with 3mm slice thickness were obtained. Anteroposterior coordinate of target was chosen at 2mm in front of the midcommissural point and lateral coordinate between 19 and 22mm from the midline. The vertical coordinate was calculated on coronal slice using a fast spin echo inversion recovery sequence(FSEIR) related to the position of the choroidal fissure and ranged over 4-5mm below the AC-PC plane. Confirmation of the anatomical target was done on axial slices using the same FSEIR sequence . Microrecording was done at the pallidum contralateral to the symptomatic side using an electrode with a tip diameter of $1{{\mu}m}$ diameter tip and 1.1-1.4 mOhm impedance at 1000Hz. Electrophysiologic localization of the target was also confirmed intraoperatively by macrostimulation. Results : Microrecording techniques were reliable to define the transition from the base of the pallidum which was characterized by the disappearance of spike activity and by the change of the audible background activity. Signals from high amplitude neurons firing at 200-400Hz were recorded in the pallidal base. X, Y and Z coordinates of target obtained from the MRI were within 1mm from the X, Y, Z coordinates obtained with microrecording in 16 patients (80%), 15 patients(75%), 10 patients(50%) respectively. The difference of Y coordinate between on MRI and on microrecording was 4mm in only one patient. Conclusion : The MRI was accurate to localize the target within 1mm of the error from microrecording target in 70% of the patients. 4mm discrepancy was observed only once. We conclude that MRI alone can be used to determine the target for pallidotomy in most patients. However, microrecording technique can still be extremely valuable in patents with aberrant anatomy or unusual MRI coordinates. We also consider physiologic confirmation of the target using macrostimulation to be mandatory in all cases.

• The Korean Journal of Nuclear Medicine
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• v.29 no.4
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• pp.526-532
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• 1995

Introduction : $^{99m}Tc$-(V)-DMSA is a tumor seeking agent that has been used to image medullary carcinoma of thyroid, soft tissue sarcoma and lung cancer. This study was designed to assess the clinical role of $^{99m}Tc$-(V)-DMSA in the diagnosis of head and neck cancers. We has evaluated the diagnostic efficacy of planar and SPECT imaging using $^{99m}Tc$-(V)-DMSA. Patients and Method : Sixty-eight patients with head and neck mass were included in this study. All subjects were diagnosed by biopsy or surgery. Planar and SPECT images were obtained at 2 or 3 hour after intravenous injection of 740 MBq(20 mCi) $^{99m}Tc$-(V)-DMSA. Seventeen patients also underwent SPECT in aging using dual head camera. Result : The diagnostic sensitivity of $^{99m}Tc$-(V)-DMSA planar and SPECT imaging was 65% and 90%, and specificity was 80% and 66%, respectively. The sensitivity of planar imaging in squamous cell carcinoma was similar to overall sensitivity Six metastatic lesion were first diagnosed by scintigraphy. But benign lesions such as Kikuchi syndrome, tuberculous lymphadenitis also revealed increased uptake. Conclusion : $^{99m}Tc$-(V)-DMSA imaging seems to be a promising method in the evaluation of patients with head and neck mass. We recommend SPECT imaging to delineate anatomic localization of the lesion.

• The Korean Journal of Nuclear Medicine
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• v.33 no.4
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• pp.368-380
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• 1999

Purpose: The purpose of this study was to evaluate and compare the scintigraphic findings and diagnostic accuracy of double-phase Tc-99m sestamibi scan in primary and secondary hyperparathyroidism (HPT). Materials and Methods: We retrospectively reviewed 16 cases of primary (18 lesions) and 11 cases of secondary HPT (44 lesions) who underwent Tc-99m-sestamibi scan before the surgical intervention. Scan was performed using LEM camera (Siemens, Germany) after the injection of 740MBq of Tc-99m sestamibi. Routine image consisted of baseline and 3-hour delayed images and each image was obtained using both parallel and pine hole collimator. The study population was 27 patients (male/female=5/22, age: $49.1{\pm}10.8$). Results: Eighteen lesions of primary HPT consisted of 13 adenomas and S hyperplasias, while all lesions of secondary HPT were hyperplasias. Among the case of primary HPT, we could detect all the lesions of 13 adenomas but only 2 lesions of 5 hyperplasias (40%) could be detected by double phase scintigraphy. Three cases of primary lesion showed decreased uptake in delayed images compared with baseline. The sensitivity, specificity, positive predictive value and accuracy of primary and secondary HPT were 58.8% (10/17), 83.3% (10/12), 83.3% (10/12), 75.9% (22/29), and 37.5% (15/40), 50% (2/4), 88.2% (15/17), 38.6% (17/44), respectively. Overall sensitivity, specificity, positive predictive value and accuracy were 43.9% (25/57), 75% (12/16), 86.2% (25/29), and 53.4% (39/73). There were no statistical difference between the weight of primary and secondary HPT lesion (p>0.05). Conclusion: Tc-99m sestamibi scan is fairly good modality to detect parathyroid lesion in patient with primary HPT before the surgical intervention. However, since some of cases may reveal decreased uptake in delayed image, a careful attention to the findings of baseline images may be helpful. Still the low accuracy of sestamibi scan in diagnosis of secondary HPT prohibits routine use of it for this disease.

• Journal of the Korean Society of Radiology
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• v.83 no.2
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• pp.344-359
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• 2022

Purpose To develop a denoising convolutional neural network-based image processing technique and investigate its efficacy in diagnosing breast cancer using low-dose mammography imaging. Materials and Methods A total of 6 breast radiologists were included in this prospective study. All radiologists independently evaluated low-dose images for lesion detection and rated them for diagnostic quality using a qualitative scale. After application of the denoising network, the same radiologists evaluated lesion detectability and image quality. For clinical application, a consensus on lesion type and localization on preoperative mammographic examinations of breast cancer patients was reached after discussion. Thereafter, coded low-dose, reconstructed full-dose, and full-dose images were presented and assessed in a random order. Results Lesions on 40% reconstructed full-dose images were better perceived when compared with low-dose images of mastectomy specimens as a reference. In clinical application, as compared to 40% reconstructed images, higher values were given on full-dose images for resolution (p < 0.001); diagnostic quality for calcifications (p < 0.001); and for masses, asymmetry, or architectural distortion (p = 0.037). The 40% reconstructed images showed comparable values to 100% full-dose images for overall quality (p = 0.547), lesion visibility (p = 0.120), and contrast (p = 0.083), without significant differences. Conclusion Effective denoising and image reconstruction processing techniques can enable breast cancer diagnosis with substantial radiation dose reduction.

• Journal of Korean Neurosurgical Society
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• v.58 no.2
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• pp.112-118
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• 2015

Objective : Thoracic ossification of the ligamentum flavum (OLF) is a relatively rare disease. Because of ambiguous clinical symptom, it is difficult for early diagnosis of OLF and subsequent treatment can be delayed or missed. Therefore, the purpose of this study is to comprehensively assess the prevalence and distribution of thoracic OLF by magnetic resonance imaging (MRI) and coexisting spinal disease in Korean patients with back pain or leg pain. Methods : The sample included 2134 Korean patients who underwent MRI evaluation for back pain. The prevalence and distribution of thoracic OLF were assessed using lumbar MRI with whole spine sagittal images. Additionally, we examined the presence of coexisting lumbar and cervical diseases. The presence of thoracic OLF as well as clinical parameters such as age, sex, and surgery were retrospectively reviewed. Results : The prevalence of thoracic OLF in total patients was 16.9% (360/2134). The prevalence tended to increase with aging and was higher in women than in men. The lower thoracic segment of T10-11 was the most frequently affected segment. Of the 360 patients with OLF, 31.9% had coexisting herniated thoracic discs at the same level. Approximately 74% of the patients with OLF had coexisting lumbar and cervical disease. Nine (2.5%) of 360 OLF patients underwent surgery for thoracic lesion. Conclusion : The prevalenceof thoracic OLF was relatively higher than those of previous reports. And coexisting lumbar and cervical disease were very frequent. Therefore, we should check coexisting spinal diseases and the exact diagnostic localization of ossification besides lumbar disease.