• Journal of Korean Neurosurgical Society
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• v.62 no.4
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• pp.476-486
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• 2019

Objective : The functional information of $^{11}C$-methionine positron emission tomography (MET-PET) images can be applied for Gamma knife radiosurgery (GKR) and its image quality may affect defining the tumor. This study conducted the phantom-based evaluation for geometric accuracy and functional characteristic of diagnostic MET-PET image co-registered with stereotactic image in Leksell $GammaPlan^{(R)}$ (LGP) and also investigated clinical application of these images in metastatic brain tumors. Methods : Two types of cylindrical acrylic phantoms fabricated in-house were used for this study : the phantom with an array-shaped axial rod insert and the phantom with different sized tube indicators. The phantoms were mounted on the stereotactic frame and scanned using computed tomography (CT), magnetic resonance imaging (MRI), and PET system. Three-dimensional coordinate values on co-registered MET-PET images were compared with those on stereotactic CT image in LGP. MET uptake values of different sized indicators inside phantom were evaluated. We also evaluated the CT and MRI co-registered stereotactic MET-PET images with MR-enhancing volume and PET-metabolic tumor volume (MTV) in 14 metastatic brain tumors. Results : Imaging distortion of MET-PET was maintained stable at less than approximately 3% on mean value. There was no statistical difference in the geometric accuracy according to co-registered reference stereotactic images. In functional characteristic study for MET-PET image, the indicator on the lateral side of the phantom exhibited higher uptake than that on the medial side. This effect decreased as the size of the object increased. In 14 metastatic tumors, the median matching percentage between MR-enhancing volume and PET-MTV was 36.8% on PET/MR fusion images and 39.9% on PET/CT fusion images. Conclusion : The geometric accuracy of the diagnostic MET-PET co-registered with stereotactic MR in LGP is acceptable on phantom-based study. However, the MET-PET images could the limitations in providing exact stereotactic information in clinical study.

• Investigative Magnetic Resonance Imaging
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• v.16 no.2
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• pp.169-172
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• 2012

Simultaneous bilateral spontaneous rupture of the quadriceps tendon is a very rare condition and only a few cases have been reported in the literature. The etiology is not clear yet. But it occurs infrequently in patients with chronic metabolic disorders, such as secondary hyperparathyroidism due to chronic renal failure. We describe a case of simultaneous spontaneous bilateral quadriceps tendon tupture in a 36-year-old male patient with secondary hyperaprathyroidism due to chronic renal failure.

• Journal of The Korean Society of Clinical Toxicology
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• v.17 no.2
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• pp.66-78
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• 2019

Purpose: Thallium (TI+) autometallography is often used for the imaging of neuronal metabolic activity in the rodent brain under various pathophysiologic conditions. The purpose of this study was to apply a thallium autometallographic technique to observe changes in neuronal activity in the forebrain of rats following acute carbon monoxide (CO) intoxication. Methods: In order to induce acute CO intoxication, adult Sprague-Dawley rats were exposed to 1100 ppm of CO for 40 minutes, followed by 3000 ppm of CO for 20 minutes. Animals were sacrificed at 30 minutes and 5 days after induction of acute CO intoxication for thallium autometallography. Immunohistochemical staining and toluidine blue staining were performed to observe cellular damage in the forebrain following intoxication. Results: Acute CO intoxication resulted in significant reduction of TI+ uptake in major forebrain structures, including the cortex, hippocampus, thalamus, and striatum. In the cortex and hippocampal CA1 area, marked reduction of TI+ uptake was observed in the cell bodies and dendrites of pyramidal neurons at 30 minutes following acute CO intoxication. There was also strong uptake of TI+ in astrocytes in the hippocampal CA3 area following acute CO intoxication. However, there were no significant histological findings of cell death and no reduction of NeuN (+) neuronal populations in the cortex and hippocampus at 5 days after acute CO intoxication. Conclusion: The results of this study suggest that thallium autometallography can be a new and useful technique for imaging functional changes in neural activity of the forebrain structure following mild to moderate CO intoxication.

• Journal of Biomedical Engineering Research
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• v.39 no.6
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• pp.237-242
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• 2018

$^{18}F$-fludeoxyglucose PET (FDG-PET) can help finding an abnormal metabolic activity in brain. In this study, we evaluated an efficiency of volume- and cortical surface-based analysis which were used to determine whether standardized uptake value ratio (SUVR) of FDG-PET was different among Alzheimer's disease (AD), mild cognitive impairment (MCI), and healthy control (HC). Each PET image was rigidly co-registered to the corresponding magnetic resonance imaging (MRI) using mutual information. All voxels of the co-registered PET images were divided by the mean FDG uptake of the cerebellum cortex which was thresholded by partial volume effect (>0.9). Also, the SUVR value of each vertex was linearly interpolated from volumetric SUVR image which was thresholded by gray matter partial volume effect (>0.1). Lobar mean values were calculated from both volume- and cortical surface-based SUVRs. Statistical analysis was conducted to compare two measures for AD, MCI and HC groups. Even though the results of volume (SUVR_vol) and cortical surface-based SUVR (SUVR_surf) analysis were not significantly different from each other, the latter would be better for detecting group differences in SUVR of PET.

• Journal of the Korean Society of Radiology
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• v.14 no.7
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• pp.947-956
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• 2020

The human body becomes vulnerable to various diseases due to deterioration in structure and function as it ages. In particular, changes in brain structure weaken the immune system against diseases such as vascular and metabolic neuropsychiatric diseases. In this study, we used a magnetic resonance imaging technique that allows non-invasive observation of brain structures and measurement of how the volumes of the brain, gray matter, white matter, and subcortical regions changes with aging in women aged 65 to 85 years. As a result of our investigation, we observed a significant linear decrease in subcortical regions with age. These results suggest that the changes due to aging in the brain structure area are closely related to neuropsychiatric diseases in old age, and can provide information in understanding the vulnerability of the brain in old age.

• The Korean Journal of Nuclear Medicine
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• v.33 no.1
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• pp.28-39
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• 1999

Purpose: We investigated the difference of glucose metabolism of medial and lateral temporal lobes of patients with temporal lobe epilepsy (TLE) utilizing quantitative comparison of regional metabolic activities using asymmetric index. Materials and Methods: We studied 19 pathologically proven mesial TLE and 25 lateral TLE patients. Lateral TLE patients were either normal on magnetic resonance imaging (cryptogenic: n=14) or had structural lesions (lesional: n= 11). Asymmetric index (ASI) was calculated as [(ipsilateral-contralateral)/(ipsilateral+contralateral)]${\times}200$. Results: ASI of medial and lateral lobes of mesial TLE was decreased ($-16.4{\pm}8.3$ and $-12.1{\pm}5.5$, respectively). In cryptogenic lateral TLE, ASI of lateral temporal lobe was decreased ($-11.8{\pm}4.7$), whereas that of medial temporal lobe was not decreased ($-4.6{\pm}6.3$). ASI of medial lobe of lesional lateral TLE was $-7.3{\pm}9.1$, which was significantly different from that of mesial TLE (p<0.05). Patients with lesional lateral TLE had evident metabolic defects or decrease (ASI: $-22{\pm}10.5$) in lateral temporal lobe. While we could not find the difference of metabolic activity in lateral temporal lobes between cryptogenic lateral TLE and mesial TLE patients, the difference of metabolic activity was significant in medial temporal lobes which was revealed by ASI quantitation. Conclusion: Asymmetric decrease of metabolic activity in both medial and lateral temporal lobes indicates medial temporal epilepsy. Symmetry of metabolic activity in medial temporal lobe combined with asymmetry of that in lateral temporal lobe may give hints that the epileptogenic zone is lateral.

• Journal of the Korean Society of Radiology
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• v.3 no.3
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• pp.13-21
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• 2009

PET/CT is a machine for imaging in vivo functions or metabolic activities after the administration of radiopharmaceuticals labeled with radioisotope emitting positrons in the body. Recently the number of PET/CT installed in Korean medical institutions is increasing rapidly. In response, the number of PET/CT tests to be used in the diagnosis and treatment of tumors is also increasing every year, and this is increasing the necessity for developing the methods of PET/CT performance evaluation and quality control. Among the test items for the performance evaluation and quality control of PET/CT suggested in NU 2-2007, this study examined spatial resolution test, sensitivity test, image quality, attenuation accuracy & scatter correction test, scatter fraction, count losses and randoms test and accuracy( correction for count losses and randoms).

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.74-74
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• 2003

Purpose: To investigate whether there are significant changes in regional brain metabolism in patients with Parkinson's disease after thalamotomy using proton magnetic resonance spectroscopy (lH MRS). Methods: Fifteen patients with Parkinson's disease of mean age 56.5 years (7 males and 8 females; mean age, 56.5 years) that have treated with levodopa were included. All patients with tremor experienced amelioration of their symptoms on the side contralateral to the thalamotomy. As a single-voxel technique, 1H MR spectra were obtained from the volume of interested regions in thalamus and primary motor cortex. Spectral parameters were: 20 ms TE, 2000 ms TR, 128 averages, 2500 Hz spectral width, and 2048 data points. Results: We found that NAA/Cho ratios showed generally low levels in thalamus in Parkinson's disease patients with clinical improvement following thalamotomy. Conclusions: 1H MRS may be a useful utility for the aid in better understanding the pathophy-siologic process in Parkinson's disease patients on the basis of the variation of NAA/Cho ratio. Acknowledgement: This study was supported by a grant of the Center for Functional and Metabolic Imaging Technology, Ministry of Health & Welfare, Republic of Korea (02-PJ3-PG6-EV07-0002).

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.73-73
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• 2003

Purpose: To determine the motor cortex dysfunction in hemiparetic patients due to deep intracerebral hematoma, authors performed proton magnetic resonance spectroscopy (lH MRS) for the evaluation of biochemical changes in the cortex on affected hemisphere according to axonal injury at the level of internal capsule. Methods: Ten control subjects and 14 patients with documentable hemiparesis of varying severity hemiparesis were included. All the hemiparesis was caused by deep intracerebral hematoma (putaminal and thalamic hemorrhage). In vivo 1H MRS study was performed on a 3T MRI/MRS system using STEAM sequence. As a single-voxel technique, Spectral parameters were: 20 ms TE, 2000 ms TR, 128 averages, 2500 Hz spectral width, and 2048 data points. Results: We found that the mean N-acetylaspartate (NAA)/phosphocreatine (Cr) and NAA/choline (Cho) ratios were significantly decreased in the motor cortex of the hemiparesis patients compared with control subjects. Conclusions: 1H MRS examinations of the motor cortex might help to differentiate distinct clinical entities of hemiparesis and to monitor pharmacological effects in therapeutic trials, providing a quantitative biological marker for motor neuron dysfunction. Acknowledgement: This study was supported by a grant of the Center for Functional and Metabolic Imaging Technology, Ministry of Health & Welfare, Republic of Korea. (02-PJ3-PG6-EV07-000).

• Clinical and Experimental Pediatrics
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• v.58 no.2
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• pp.73-76
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• 2015

Isolated sphenoid sinusitis is a rare disease in children, and its symptoms are often nonspecific and confusing. Rarely, severe headache can be the first or only symptom of isolated sphenoid sinusitis. New daily persistent headache (NDPH) is a form of chronic daily headache that may have features of both migraines and tension-type headaches. NDPH is difficult to diagnose and requires a multifaceted approach. Here, we report on a 10-year-old boy and an 11-year-old girl who both presented with typical NDPH symptoms. These patients had no nasal symptoms or signs of infection. Neither nonsteroidal anti-inflammatory drugs nor topiramate had any effect on the headaches. Their neurological and ophthalmological examinations were normal. The results of routine blood work, including thyroid function tests, inflammatory markers, complete blood count, tests for viral infection, and a metabolic panel, were normal. A brain magnetic resonance imaging scan showed isolated sphenoid sinusitis. Both patients' symptoms resolved completely after approximately 1 month of oral antibiotics for sinusitis.