• International Journal of Computer Science & Network Security
• /
• v.24 no.5
• /
• pp.53-63
• /
• 2024

Alzheimer's disease is a brain disorder that worsens over time and affects millions of people around the world. It leads to a gradual deterioration in memory, thinking ability, and behavioral and social skills until the person loses his ability to adapt to society. Technological progress in medical imaging and the use of artificial intelligence, has provided the possibility of detecting Alzheimer's disease through medical images such as magnetic resonance imaging (MRI). However, Deep learning algorithms, especially convolutional neural networks (CNNs), have shown great success in analyzing medical images for disease diagnosis and classification. Where CNNs can recognize patterns and objects from images, which makes them ideally suited for this study. In this paper, we proposed to compare the performances of Alzheimer's disease detection by using two deep learning methods: You Only Look Once (YOLO), a CNN-enabled object recognition algorithm, and Visual Geometry Group (VGG16) which is a type of deep convolutional neural network primarily used for image classification. We will compare our results using these modern models Instead of using CNN only like the previous research. In addition, the results showed different levels of accuracy for the various versions of YOLO and the VGG16 model. YOLO v5 reached 56.4% accuracy at 50 epochs and 61.5% accuracy at 100 epochs. YOLO v8, which is for classification, reached 84% accuracy overall at 100 epochs. YOLO v9, which is for object detection overall accuracy of 84.6%. The VGG16 model reached 99% accuracy for training after 25 epochs but only 78% accuracy for testing. Hence, the best model overall is YOLO v9, with the highest overall accuracy of 86.1%.

• Korean Journal of Radiology
• /
• v.25 no.4
• /
• pp.374-383
• /
• 2024

Objective: To evaluate the diagnostic performance and image quality of 1.5-mm slice thickness MRI with deep learningbased image reconstruction (1.5-mm MRI + DLR) compared to routine 3-mm slice thickness MRI (routine MRI) and 1.5-mm slice thickness MRI without DLR (1.5-mm MRI without DLR) for evaluating temporal lobe epilepsy (TLE). Materials and Methods: This retrospective study included 117 MR image sets comprising 1.5-mm MRI + DLR, 1.5-mm MRI without DLR, and routine MRI from 117 consecutive patients (mean age, 41 years; 61 female; 34 patients with TLE and 83 without TLE). Two neuroradiologists evaluated the presence of hippocampal or temporal lobe lesions, volume loss, signal abnormalities, loss of internal structure of the hippocampus, and lesion conspicuity in the temporal lobe. Reference standards for TLE were independently constructed by neurologists using clinical and radiological findings. Subjective image quality, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were analyzed. Performance in diagnosing TLE, lesion findings, and image quality were compared among the three protocols. Results: The pooled sensitivity of 1.5-mm MRI + DLR (91.2%) for diagnosing TLE was higher than that of routine MRI (72.1%, P < 0.001). In the subgroup analysis, 1.5-mm MRI + DLR showed higher sensitivity for hippocampal lesions than routine MRI (92.7% vs. 75.0%, P = 0.001), with improved depiction of hippocampal T2 high signal intensity change (P = 0.016) and loss of internal structure (P < 0.001). However, the pooled specificity of 1.5-mm MRI + DLR (76.5%) was lower than that of routine MRI (89.2%, P = 0.004). Compared with 1.5-mm MRI without DLR, 1.5-mm MRI + DLR resulted in significantly improved pooled accuracy (91.2% vs. 73.1%, P = 0.010), image quality, SNR, and CNR (all, P < 0.001). Conclusion: The use of 1.5-mm MRI + DLR enhanced the performance of MRI in diagnosing TLE, particularly in hippocampal evaluation, because of improved depiction of hippocampal abnormalities and enhanced image quality.

• Korean Journal of Radiology
• /
• v.23 no.12
• /
• pp.1269-1280
• /
• 2022

Objective: This study aimed to evaluate the usefulness of quantitative indices obtained from deep learning analysis of gadoxetic acid-enhanced hepatobiliary phase (HBP) MRI and their longitudinal changes in predicting decompensation and death in patients with advanced chronic liver disease (ACLD). Materials and Methods: We included patients who underwent baseline and 1-year follow-up MRI from a prospective cohort that underwent gadoxetic acid-enhanced MRI for hepatocellular carcinoma surveillance between November 2011 and August 2012 at a tertiary medical center. Baseline liver condition was categorized as non-ACLD, compensated ACLD, and decompensated ACLD. The liver-to-spleen signal intensity ratio (LS-SIR) and liver-to-spleen volume ratio (LS-VR) were automatically measured on the HBP images using a deep learning algorithm, and their percentage changes at the 1-year follow-up (ΔLS-SIR and ΔLS-VR) were calculated. The associations of the MRI indices with hepatic decompensation and a composite endpoint of liver-related death or transplantation were evaluated using a competing risk analysis with multivariable Fine and Gray regression models, including baseline parameters alone and both baseline and follow-up parameters. Results: Our study included 280 patients (153 male; mean age ± standard deviation, 57 ± 7.95 years) with non-ACLD, compensated ACLD, and decompensated ACLD in 32, 186, and 62 patients, respectively. Patients were followed for 11-117 months (median, 104 months). In patients with compensated ACLD, baseline LS-SIR (sub-distribution hazard ratio [sHR], 0.81; p = 0.034) and LS-VR (sHR, 0.71; p = 0.01) were independently associated with hepatic decompensation. The ΔLS-VR (sHR, 0.54; p = 0.002) was predictive of hepatic decompensation after adjusting for baseline variables. ΔLS-VR was an independent predictor of liver-related death or transplantation in patients with compensated ACLD (sHR, 0.46; p = 0.026) and decompensated ACLD (sHR, 0.61; p = 0.023). Conclusion: MRI indices automatically derived from the deep learning analysis of gadoxetic acid-enhanced HBP MRI can be used as prognostic markers in patients with ACLD.

• Investigative Magnetic Resonance Imaging
• /
• v.18 no.2
• /
• pp.120-132
• /
• 2014

Purpose : To compare dynamic susceptibility contrast imaging, diffusion-weighted imaging, and susceptibility-weighted imaging (SWI) for the differentiation of tumor recurrence and delayed radiation therapy (RT)-related changes in patients treated with RT for primary brain tumors. Materials and Methods: We enrolled 24 patients treated with RT for various primary brain tumors, who showed newly appearing enhancing lesions more than one year after completion of RT on follow-up MRI. The enhancing-lesions were confirmed as recurrences (n=14) or RT-changes (n=10). We calculated the mean values of normalized cerebral blood volume (nCBV), apparent diffusion coefficient (ADC), and proportion of dark signal intensity on SWI (proSWI) for the enhancing-lesions. All the values between the two groups were compared using t-test. A multivariable logistic regression model was used to determine the best predictor of differential diagnosis. The cutoff value of the best predictor obtained from receiver-operating characteristic curve analysis was applied to calculate the sensitivity, specificity, and accuracy for the diagnosis. Results: The mean nCBV value was significantly higher in the recurrence group than in the RT-change group (P=.004), and the mean proSWI was significantly lower in the recurrence group (P<.001). However, no significant difference was observed in the mean ADC values between the two groups. A multivariable logistic regression analysis showed that proSWI was the only independent variable for the differentiation; the sensitivity, specificity, and accuracy were 78.6% (11 of 14), 100% (10 of 10), and 87.5% (21 of 24), respectively. Conclusion: The proSWI was the most promising parameter for the differentiation of newly developed enhancing-lesions more than one year after RT completion in brain tumor patients.

• Korean Journal of Biological Psychiatry
• /
• v.3 no.2
• /
• pp.203-210
• /
• 1996

Objects : To investigate the relationship between the age of onset with the atrophy and the white matter hyperintensities observed in the brain MRI of Alzheimer patients. Methods : The authors measured volumetrically cortical and ventricular brain atrophy and rated semiquantitatively white matter signal hyperintensities in nine presenile and 18 senile Alzheimer patients, who were matched for dementia severity, according to NINCDS-ADRDA criteria and in age-matched 10 presenile and 11 senile control subjects. Results : Presenile Alzheimer patients showed significantly greater cortical and ventricular atrophy indices(p<0.05) but no difference in white matter hyperintensity scores compared to the age-matched control group. On the contrary, senile Alzheimer patients showed significantly greater white matter hyperintensity scores(p<0.05) but no difference in cortical and ventricular atrophy indices compared to the age-matched control group. Conclusion : An earlier onset was related to marked brain atrophy with less white matter lesions and a later onset is related to marked white matter lesions with less brain atrophy in Alzheimer's disease. Our results suggested the passible difference in the pathophysiology between the presenile and the senile-onset Alzheimer's disease.

• Clinical and Experimental Pediatrics
• /
• v.46 no.2
• /
• pp.137-142
• /
• 2003

Purpose : This study was performed to determine the sensitivity of neonatal electroencephalography (EEG) in detecting underlying brain disease, to compare the sensitivity and specificity of EEG with those of brain ultrasonography and to determine the prognostic value of EEG for neonatal neurologic diseases. Methods : Eighty-seven newborn babies were subjected to a electroencephalographic examination for the evaluation of underlying neurological diseases and EEGs were recorded at least before three days of life. The findings of early ultrasonography performed within three days after birth were compared with those of magnetic resonance imaging(MRI) or ultrasonography after seven days of life. Results : The EEG results were more sensitive and specific than ultrasonography for the detection of neonatal brain damage. The EEG results showed 91.7% sensitivity for mild grade neurological sequelae and 100.0% sensitivity for moderate and severe-grade neurological sequelae in predicting the neurological outcome. However, early ultrasonography results showed 20.8% and 18.8% of sensitivity and specificity, respectively. Conclusion : EEG is a highly sensitive diagnostic tool for detecting neonatal brain disease and is valuable for predicting the long-term outcome of neurologic sequelae.

• Journal of radiological science and technology
• /
• v.39 no.1
• /
• pp.51-57
• /
• 2016

Acoustic noise during magnetic resonance imaging (MRI) is the main source for patient discomfort. we report our preliminary experience with this technique in neuroimaging with regard to subjective and objective noise levels and image quality. 60 patients(29 males, 31 females, average age of 60.1) underwent routine brain MRI with 3.0 Tesla (MAGNETOM Tim Trio; Siemens, Germany) system and 12-channel head coil. Q-$T_2$ and $T_2$ sequence were performed. Measurement of sound pressure levels (SPL) and heart rate on Q-$T_2$ and $T_2$ was performed respectively. Quantitative analysis was carried out by measuring the SNR, CNR, and SIR values of Q-$T_2$, $T_2$ and a statistical analysis was performed using independent sample T-test. Qualitative analysis was evaluated by the eyes for the overall quality image of Q-$T_2$ and $T_2$. A 5-point evaluation scale was used, including excellent(5), good(4), fair(3), poor(2), and unacceptable(1). The average noise and peak noise decreased by $15dB_A$ and $10dB_A$ on $T_2$ and Q-$T_2$ test. Also, the average value of heartbeat rate was lower in Q-$T_2$ for 120 seconds in each test, but there was no statistical significance. The quantitative analysis showed that there was no significant difference between CNR and SIR, and there was a significant difference (p<0.05) as SNR had a lower average value on Q-$T_2$. According to the qualitative analysis, the overall quality image of 59 case $T_2$ and Q-$T_2$ was evaluated as excellent at 5 points, and 1 case was evaluated as good at 4 points due to a motion artifact. Q-$T_2$ is a promising technique for acoustic noise reduction and improved patient comfort.

• Investigative Magnetic Resonance Imaging
• /
• v.10 no.1
• /
• pp.1-7
• /
• 2006

Purpose : Recent development of diffusion tensor imaging enables the evaluation of the microstructural characteristics of the brain white matter. However, optimal imaging parameters for diffusion tensor imaging, particularly concerning the number of diffusion gradient direction, have not been studied thoroughly yet. The purpose of this study was to evaluate the influence of the number of diffusion gradient direction on the fiber tracking of the white matter. Materials and methods : 13 healthy volunteers (ten men and three women, mean age 30 years, age range 23-37 years) were included in this study. Diffusion tensor imaging was performed with different numbers of diffusion gradient direction as 6, 15, and 32, keeping the other imaging parameters constant. The imaging field ranged from 1 cm below the pons to 2-3 cm above the lateral ventricle, parallel to the anterior commissure-posterior commissure line. FA (fractional anisotropy) maps were created via image postprocessing, and then FA and its standard deviation were calculated in the genu and the splenium of the corpus callosum on each of FA maps. Fiber tracking of the corticospinal tract in the brain was performed and the number of the reconstructed fibers of the tract was measured. FA, standard deviation of FA and the number of the reconstructed fibers were compared statistically between the different diffusion gradient directions. Results : FA is not statistically significantly different between the different diffusion gradient directions. By increasing the number of diffusion gradient direction, standard deviation of FA decreased significantly, and the number of the reconstructed fibers increased significantly. Conclusion : The higher number of diffusion gradient direction provided better quality of fiber tracking.

• Journal of Veterinary Clinics
• /
• v.23 no.3
• /
• pp.366-370
• /
• 2006

Arachnoid cysts are intra-arachnoid collections of cerebrospinal fluid. They may cause neurological deficit through expansion that can compress normal neural tissue and obstruct cerebrospinal fluid flow. Intracranial arachnoid cysts were found in 4 patients aged 10 months to 20 months(mean age 15 months). The presenting symptoms included circling(dog 2,3), seizure(dog 1), progressive weakness(dog 1,2,3), increasing scoliosis(dog 3), worsening spasticity(dog 3), and salivation(dog 3). One patient showed no symptoms from the intracranial arachnoid cyst. There were no significant findings in complete blood count and serum chemistry. Computed tomography(CT) with/without magnetic resonance imaging(MRI) scans were performed in these cases. Hypodense intracranial arachnoid cyst was observed on CT images in dog 4. Sagittal T1-weighted(T1W) and T2-weighted(T2W) images and transverse T1W and T2W images revealed a intracranial arachnoid cysts with syringohydromyelia(dog 3) and hydrocephalus(dog 3,4) in the brain. Clinical signs of three cases were improved by medication.

• Proceedings of the Korean Society for Cognitive Science Conference
• /
• 2002.05a
• /
• pp.216-221
• /
• 2002

본 연구는 문자 규칙 심층성이 다른 문자체계인 한국어와 중국어의 차이가 이중언어화자의 모국어 처리와 외국어 처리에서 각각 어떤 대뇌 활성화의 차이를 가져오는지 fMRI (functional Magnetic Resonance Imaging)를 이용하여 살펴보았다. 중국어 (Ll)-한국어(L2) 이중언어화자 및 한국어(Ll)-중국어(L2) 이중언어화자를 제 2언어 습득시기에 따라 초기 및 후기 이중언어화자로 구분하여 모국어 차이와 습득시기에 따른 영향을 알아보았다. 실험 1에서는 어휘 판단 과제(lexical decision task)를 실시하였고, 실험 2에서는 의미 판단 과제(semantic decision task)를 각각 실시하였다. 어휘판단과제를 사용한 실험 1의 결과는 음운처리와 관련된 좌반구 SMG(supramarginal gyrus), 하두정소엽(inferior parietal lobule, BA 39, 40)에서 중국어-한국어 초기 및 후기이중언어화자의 경우, 한국어 조건에서 보다 많은 활성화를 보였으나, 한국어-중국어 화자의 경우 활성화가 나타나지 않았다. 철자처리에 관련된 방추상회(fusiform gyrus, BA 37, 19) 영역에서는 중국어-한국어 화자뿐만 아니라, 한국어-중국어 인중언어화자의 경우도 중국어 조건에서 보다 많은 활성화를 보였다. 실험 2에서 사용한 의미판단과제의 경우, 중국어-한국어 이중언어화자의 경우 어휘판단과제를 사용한 실험 1의 결과에서 보고된 한국어 특정적인 반응, 즉 SMG영역에서의 활성화의 증가가 실험 2에서는 나타나지 않았다. 그러나 한국어-중국어 이중언어화자의 경우, 실험 1에서 나타난 것과 같이 철자처리 혹은 의미처리와도 관련된다고 보고되는 방추상회(fusiform gyrus)등의 영역 유의미한 차이를 나타났다. 이는 어휘 판단과제와 의미판단과제가 유도하는 뇌 활성화 양상이 다름을 시사한다. 종합해 볼 때, 이중언어화자의 뇌 영상 연구에서 어휘수준에서는 거의 공통적인 활성화를 보인다는 개략적 수준의 연구 결과를 넘어, 음운처리 및 철자처리와 같은 어휘접근 수준에서는 이중언어화자들의 뇌 활성화가 다르게 일어남을 보여주고 있다. 따라서 이중언어 화자의 뇌 기전을 밝히기 위해서도 보다 개략적 수준을 넘어 언어처리의 세부적인 수준에 따른 접근이 필요함을 시사한다.