• Investigative Magnetic Resonance Imaging
• /
• v.24 no.1
• /
• pp.30-37
• /
• 2020

Purpose: Preterm infants are at high risk for adverse neurodevelopmental outcomes. Magnetic resonance imaging (MRI) has been proposed as a means of predicting neurodevelopmental outcomes in this population. It is controversial whether diffuse excessive high signal intensity (DEHSI) represents damage to the white matter or delayed myelination in preterm infants. This study investigated MRI findings for predicting the severity of neurodevelopmental outcomes and assessing whether preterm infants with DEHSI near term-equivalent age have abnormal neurodevelopmental outcomes. Materials and Methods: Preterm infants (n = 64, gestational age at birth < 35 weeks) undergoing brain MRI near term-equivalent age and subsequent neurodevelopmental outcomes were evaluated between 18 and 24 months of age. The associations of MRI findings and the risk of severe cognitive delay, severe psychomotor delay, cerebral palsy (CP), and neurosensory impairment were analyzed. The associations of DEHSI with risks of severe cognitive delay, severe psychomotor delay, CP, and neurosensory impairment (hearing or visual impairment) were analyzed. Outcome data were evaluated by logistic regression and the Fisher's exact test. Results: There were significant associations between abnormal white matter findings and delayed mental development, delayed psychomotor development, neurosensory impairment, and presence of CP. The presence of DEHSI was not correlated with delayed neurodevelopmental outcomes or presence of CP. In multivariate logistic regression analyses, cystic encephalomalacia, punctate lesion, loss of white matter volume and ventricular dilation were significantly associated with CP. Conclusion: Abnormal MRI findings near term-equivalent age in preterm infants predict adverse neurodevelopmental outcomes. No significant association between DEHSI and adverse neurodevelopmental outcomes was demonstrated.

• Journal of Korean Neurosurgical Society
• /
• v.55 no.5
• /
• pp.267-272
• /
• 2014

Objective : Differentiation of demyelination in white matter from axonal damage can be determined using diffusion tensor imaging (DTI). In this study using meningioma patients an attempt was made to evaluate the relationship between preoperative weakness and the changes of diffusion parameters in the corticospinal tract (CST) using DTI. Methods : Twenty-six patients with meningioma were enrolled in this study. Eleven of them suffered from objective motor weakness and were classified as Group 1. The remaining 15 patients did not present motor weakness and were classified as Group 2. Fiber tractography and CST diffusion parameters were obtained using DTIStudio. The ratios (lesion side mean value/contralateral side mean value) of CST diffusion parameters were compared with 1.0 as a test value using a one-sample t-test. Results : In Group 1, fractional anisotropy (FA), tensor trace (TT), and radial diffusivity (RD, ${\lambda}2$ and ${\lambda}3$) of the CST were significantly different between two hemispheres, but axial diffusivity (AD, ${\lambda}1$) of the CST was not significantly different between two hemispheres. In Group 2, FA and ${\lambda}3$ of CST did not differ significantly between the hemispheres. In Group 2, TT, ${\lambda}1$, and ${\lambda}2$ of CST in the ipsilateral hemisphere were significantly higher than those of the unaffected hemisphere. However, the differences were small. Conclusion : Motor weakness was related to a low FA and high TT resulting from increased RD of the CST fibers. CST diffusion changes in patients with weakness are similar to those for demyelination.

• Journal of Trauma and Injury
• /
• v.31 no.2
• /
• pp.51-57
• /
• 2018

Purpose: Patients with diffuse axonal injury experience various disabilities and have a high cost of treatment. Recent researches have revealed the underlying mechanism and pathogenesis of diffuse axonal injury. This study aimed to investigate the correlation between the radiological grading of diffuse axonal injury and the clinical outcomes of patients. Methods: From January 2011 to December 2016, among 294 patients with traumatic brain injury, 44 patients underwent magnetic resonance imaging (MRI). A total of 18 patients were enrolled in this study except for other cerebral injuries, such as cerebral hemorrhage or hypoxic brain damage. Demographic data, clinical data, and radiological findings were retrospectively reviewed. The grading of diffuse axonal injury was analyzed based on patient's MRI findings. Results: For the most severe diffuse axonal injury patients, prolonged intensive care unit (ICU) stay (p=0.035), hospital stay (p=0.012), and prolonged mechanical ventilation (p=0.030) were observed. However, there was no significant difference in healthcare-associated infection rates between MRI grading (p=0.123). Massive transfusion, initial hemoglobin and lactate levels, and MRI gradings were found to be highly significant in predicting the duration of unconsciousness. Conclusions: This study showed that patients with high grade diffuse axonal injury have prolonged ICU stays and significantly longer hospital stays. Deteriorated mental patients with high energy injuries should be evaluated to identify diffuse axonal injuries by using an appropriate imaging tool, such as MRI. It will be important to predict the duration of consciousness recovery using MRI scans.

• Journal of Radiopharmaceuticals and Molecular Probes
• /
• v.1 no.2
• /
• pp.137-144
• /
• 2015

Hypoxia is an important adverse prognostic factor for tumor progression and is a major cause of failure of radiation therapy. In case of short-term hypoxia, the metabolism can recover to normal, but if hypoxia persists, it causes irreversible cell damage and finally leads to death. So a hypoxia marker would be very useful in oncology. In particular, 2-nitroimidazole can be reduced to form a reactive chemical species, which can bind irreversibly to cell components in the absence of sufficient oxygen, thus, the development of radiolabeled nitroimidazole derivatives for the imaging of hypoxia remains an active field of research to improve cancer therapy result. 2-nitroimidazole based hypoxia marker, [$^{18}F$]FMISO holds promise for the evaluation of tumor hypoxia by Positron emission tomography (PET), at both global and local levels. In the present study, [$^{18}F$]FMISO was synthesized using an automatic synthesis module with high radiochemical purity (>99%) in 60 min. Immunohistochemical analysis using pimonidazole confirmed the presence of hypoxia in xenografted CT-26 tumor tissue. A biodistribution study in CT-26 xenografted mice showed that the increased tumor-to-muscle ratio and tumor-to-blood ratios from 10 to 120 min post-injection. In the PET study, [$^{18}F$]FMISO also showed increased tumor-to-muscle ratios from 10 to 120 min post-injection. In conclusion, this study demonstrates the feasibility and utility of [$^{18}F$]FMISO for imaging hypoxiain mouse colon cancer model using small animal PET.

• Journal of Korean Neurosurgical Society
• /
• v.60 no.5
• /
• pp.485-497
• /
• 2017

Surgical treatment of the degenerative disc disease has evolved from traditional open spine surgery to minimally invasive spine surgery including endoscopic spine surgery. Constant improvement in the imaging modality especially with introduction of the magnetic resonance imaging, it is possible to identify culprit degenerated disc segment and again with the discography it is possible to diagnose the pain generator and pathological degenerated disc very precisely and its treatment with minimally invasive approach. With improvements in the optics, high resolution camera, light source, high speed burr, irrigation pump etc, minimally invasive spine surgeries can be performed with various endoscopic techniques for lumbar, cervical and thoracic regions. Advantages of endoscopic spine surgeries are less tissue dissection and muscle trauma, reduced blood loss, less damage to the epidural blood supply and consequent epidural fibrosis and scarring, reduced hospital stay, early functional recovery and improvement in the quality of life & better cosmesis. With precise indication, proper diagnosis and good training, the endoscopic spine surgery can give equally good result as open spine surgery. Initially, endoscopic technique was restricted to the lumbar region but now it also can be used for cervical and thoracic disc herniations. Previously endoscopy was used for disc herniations which were contained without migration but now days it is used for highly up and down migrated disc herniations as well. Use of endoscopic technique in lumbar region was restricted to disc herniations but gradually it is also used for spinal canal stenosis and endoscopic assisted fusion surgeries. Endoscopic spine surgery can play important role in the treatment of adolescent disc herniations especially for the persons who engage in the competitive sports and the athletes where less tissue trauma, cosmesis and early functional recovery is desirable. From simple chemonucleolysis to current day endoscopic procedures the history of minimally invasive spine surgery is interesting. Appropriate indications, clear imaging prior to surgery and preplanning are keys to successful outcome. In this article basic procedures of percutaneous endoscopic lumbar discectomy through transforaminal and interlaminar routes, percutaneous endoscopic cervical discectomy, percutaneous endoscopic posterior cervical foraminotomy and percutaneous endoscopic thoracic discectomy are discussed.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.4
• /
• pp.197-203
• /
• 2015

Nuclear power plant has increased continuously for power production in all over the world and the interest about nuclear accident and the dismantling of aging nuclear power plant has been a growing. The leaked radioactive source that is generated by radiation accidents must detect and remove to minimized the damage as soon as possible. Gamma-ray detection system that have been developed until now cannot provide the precise position of radioactive sources because they detect and imaging the position of radiation sources in just two dimensions. In this paper, stereo gamma ray detection system has developed and the algorithm for calculation of the distance has implemented to be able to measure the distribution of the leakage gamma ray source for the system. Stereo camera calibration for distance detection was conducted with the correction pattern and LED light and we carried out performance test of the system for the LED light source and a gamma ray source. In both experiments the results of the performance test, it was confirmed to have a 5% error. The results of this paper is used as a material for the development of gamma-ray imaging device.

• Nuclear Engineering and Technology
• /
• v.54 no.2
• /
• pp.514-522
• /
• 2022

Non-destructive testing (NDT) technology is a widely used inspection method for agricultural products. Compared with the conventional inspection method, there is no extensive sample preparation for NDT technology, and the sample is not damaged. In particular, NDT technology is used to inspect the internal structure of agricultural products infested by pests. The introduction and spread of pests during the import and export process can cause significant damage to the agricultural environment. Until now, pest detection in agricultural products and quarantine processes have been challenging because they used external inspection methods. However, NDT technology is advantageous in these inspection situations. In this pilot study, we investigated the feasibility of X-ray computed tomography (X-ray CT) and magnetic resonance imaging (MRI) to identify pest infestation in agricultural products. Three kinds of artificially pest-infested fruits (mango, tangerine, and chestnut) were non-destructively inspected using X-ray CT and MRI. X-ray CT was able to identify all pest infestations in fruits, while MRI could not detect the pest-infested chestnut. In addition, X-ray CT was superior to the quarantine process than MRI based on the contrast-to-noise ratio (CNR), image acquisition time, and cost. Therefore, X-ray CT is more appropriate for the pest quarantine process of fruits than MRI.

• Annals of Clinical Neurophysiology
• /
• v.23 no.2
• /
• pp.108-116
• /
• 2021

Background: Nitrous oxide (N₂O) is used in surgery and dentistry for its anesthetic and analgesic effects. However, neurological and psychiatric manifestations of N₂O abuse have been increasingly reported among Korean adults. The aim of this study was to demonstrate laboratory findings of N₂O abuse in Korean patients. Methods: Patients diagnosed with N₂O-induced neuropathy or myelopathy from August 2018 to December 2019 were enrolled. Their clinical presentations and laboratory and imaging findings were analyzed. Results: Sensory changes and limb weakness were present in nine of the enrolled patients. The laboratory findings revealed that seven patients had high homocysteine levels and five had high methylmalonic acid levels in their blood. Nerve conductions studies indicated that axonal neuropathy was present in four cases and longer F-wave and Hoffman's-reflex latencies were present in two cases. Signal changes in cervical spine imaging occurred in five patients, while two had normal results. Conclusions: Chronic N₂O abuse can cause neurological damage or psychiatric problems. Because N₂O is illegal for recreational use in Korea, patients tend to hide their history of use. Even though the spinal imaging results were normal, clinicians should consider the possibility of N₂O use, and further electrophysiological tests should be applied for precise evaluations.

• Food Science of Animal Resources
• /
• v.43 no.5
• /
• pp.840-858
• /
• 2023

This study was designed to compare the quality changes in mackerel fillets stored under different conditions by using hyperspectral imaging (HSI) techniques. Fillets packaged in vacuum were stored for six days under five different conditions: refrigerated at 4℃ (R group); iced at 5±3℃ (I group); kept at an ambient of 17±2℃ (A group); frozen at -18℃ for 24 h and thawed in a refrigerator at 4℃ for 5 h on the sampling day (FTR group); FTR thawed in tap water instead of thawing in a refrigerator (FTW group). The FTR group had the lowest total bacterial count, drip loss, 2-thiobarbituric acid reactive substances, volatile basic nitrogen, and texture profile analysis values among groups during the entire storage period (p<0.05). Scanning electron microscopy revealed that the FTR group had less damage, while the other groups had shrunken muscle tissues. HIS integrated with the partial least squares model yielded reliable and efficient results, with high R²_cv values, for several quality parameters of the mackerel fillets. Overall, the FTR group, involving freezing and thawing in a refrigerator, appears to be the most favorable option for maintaining the quality of mackerel fillets, which could be practically implemented in the industry. HSI is a suitable and effective technique for determining the quality of mackerel fillets stored under different conditions.

• Korean Journal of Radiology
• /
• v.2 no.1
• /
• pp.21-27
• /
• 2001

Objective: To identify and evaluate the lateral border zone by comparing the size and distribution of the abnormal signal area demonstrated by MR imaging with the infarct area revealed by pathological examination in a reperfused myocardial infarction cat model. Materials and Methods: In eight cats, the left anterior descending coronary artery was occluded for 90 minutes, and this was followed by 90 minutes of reperfusion. ECG-triggered breath-hold turbo spin-echo T2-weighted MR images were initially obtained along the short axis of the heart before the administration of contrast media. After the injection of Gadomer-17 and Gadophrin-2, contrast-enhanced T1-weighted MR images were obtained for three hours. The size of the abnormal signal area seen on each image was compared with that of the infarct area after TTC staining. To assess ultrastructural changes in the myocardium at the infarct area, lateral border zone and normal myocardium, electron microscopic examination was performed. Results: The high signal area seen on T2-weighted images and the enhanced area seen on Gadomer-17-enhanced T1WI were larger than the enhanced area on Gadophrin-2-enhanced T1WI and the infarct area revealed by TTC staining; the difference was expressed as a percentage of the size of the total left ventricle mass (T2= 39.2 %; Gadomer-17 =37.25 % vs Gadophrin-2 = 29.6 %; TTC staining = 28.2 %; p < 0.05). The ultrastructural changes seen at the lateral border zone were compatible with reversible myocardial damage. Conclusion: In a reperfused myocardial infarction cat model, the presence and size of the lateral border zone can be determined by means of Gadomer-17- and Gadophrin-2-enhanced MR imaging.