• Journal of Veterinary Clinics
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• v.34 no.5
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• pp.377-380
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• 2017

An 8-year-old, shih-tzu female dog was referred due to neurological signs including paraparesis and back pain. On the complete blood count, hematologic analysis showed elevated leukocytosis. Serum biochemical analysis revealed elevated serum alkaline phosphatase concentration and C-reactive protein concentration. On the neurologic exam, the dog was suspected to have thoracolumbar myelopathy. On magnetic resonance imaging, there were masses within the spinal canal at L1-3 intervertebral disc space that were located dorsal to spinal cord. It was hyperintense on T1-, T2-weighted magnetic resonance images, Fluid-attenuated inversion recovery, and fat suppression images. The contrast-enhanced T1-weighted images showed no enhancement. The lesions were well circumscribed. The spinal cord was compressed and displaced ventrally by the mass. After removal of the masses via L1-L3 dorsal laminectomy, pyogranulomatous inflammation was confirmed by histopathological examination. Six months after surgery, the dog recovered uneventfully and remained fully ambulatory with no neurological deficits. This case demonstrates the utility of magnetic resonance imaging for the diagnosis of spinal canal pyogranulomatous inflammation.

• Journal of the Korean Magnetic Resonance Society
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• v.5 no.2
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• pp.110-117
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• 2001

$^{19}$ F imaging of mice was carried out. For $^{19}$ F imaging, 5-flouro-uracil (5-FU) was injected into a mouse and in vivo detection of the catabolism of 5-FU to a-fluoro-P-alanine (FBAL) was carried out. The chemical shift selective (CHESS) imaging technique was employed. The 19F spectra and images give temporal and spatial information of the metabolism for 5-FU in mice.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.11
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• pp.2425-2431
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• 1997

The increased usage of Magnetic Resonance Image (MRI) required the method for automatic segmentation of medical image that is more useful so as to diagnose the dissecitive information of a atient quickly and effectively through MR scans.The use of neural networks may give much hep to solving the complex problems concerned the matter. This paper proposes the new method for automatic segmentation of magnetic resonance (MR) images of the brain by using neural networks brained by back-propagation algorithm. The trained neural networks by the segmenting MR images of a patient produce an output that networks can segment MR images of the other patients automatically, too and show a clear image of the brain.

• Investigative Magnetic Resonance Imaging
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• v.23 no.3
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• pp.220-227
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• 2019

Purpose: To evaluate the usefulness of wash-in color map in detecting early enhancement of prostate focal lesion compared to whole dynamic contrast-enhanced MRI (DEC MRI) images. Materials and Methods: This study engaged 50 prostate cancer patients who underwent multiparametric MRI and radical prostatectomy as subjects. An expert [R1] and a trainee [R2] independently evaluated early enhancement and recorded the time needed to review 1) a wash-in color map and 2) whole DCE MRI images. Results: The review of whole DCE images by R1 showed fair agreement with color map by R1, whole images by R2, and color map by R2 (weighted kappa values = 0.59, 0.44, and 0.58, respectively). Both readers took a significantly shorter time to review the color maps as compared to whole images (P < 0.001). Conclusion: A trainee could achieve better agreement with an expert when using wash-in color maps than when using whole DCE MRI images. Also, color maps took a significantly shorter evaluation time than whole images.

• Journal of Veterinary Clinics
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• v.37 no.6
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• pp.317-323
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• 2020

The aims of this study were to describe the appearance and size of the normal canine prostate using magnetic resonance (MR) imaging and to calculate the apparent diffusion coefficient (ADC) values. MR images were obtained from seven intact male beagle dogs using a 1.5 T MR unit. The sequences included pre- and post-contrast T1- and T2-weighted imaging with and without fat saturation. The signal intensity of the prostate was compared with the adjacent musculature, fat, and urine in the urinary bladder. We recorded the mean prostatic length, width, and height and the length of the sixth lumbar vertebral body (L6). In addition, the prostatic length (rL), width (rW), and height (rH) ratios to L6 were calculated. Diffusion-weighted images of the prostate were obtained and ADC values were calculated. The prostate was bilobed and oval-shaped, homogenous on T1-weighted images, and heterogeneous with radiating lines on T2-weighted images. Post-contrast T1-weighted sequences showed contrast enhancement of the central and radiating striations. The prostatic capsule was clearly identified on post-contrast T1-weighted images with fat saturation. The ADC values were 1.72-2.04 × 10-3mm2/sec (mean, 1.88 × 10-3mm2/sec). Knowledge of the normal appearance of the prostate on MR images is essential to assess prostatic diseases in dogs.

• Korean Journal of Radiology
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• v.20 no.1
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• pp.114-125
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• 2019

Objective: Segmented cardiac cine magnetic resonance imaging (MRI) is the gold standard for cardiac ventricular volumetric assessment. In patients with difficulty in breath-holding or arrhythmia, this technique may generate images with inadequate quality for diagnosis. Real-time cardiac cine MRI has been developed to address this limitation. We aimed to assess the performance of retrospective electrocardiography-gated real-time cine MRI at 3T for left ventricular (LV) volume and mass measurement. Materials and Methods: Fifty-one patients were consecutively enrolled. A series of short-axis cine images covering the entire left ventricle using both segmented and real-time balanced steady-state free precession cardiac cine MRI were obtained. End-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), and LV mass were measured. The agreement and correlation of the parameters were assessed. Additionally, image quality was evaluated using European CMR Registry (Euro-CMR) score and structure visibility rating. Results: In patients without difficulty in breath-holding or arrhythmia, no significant difference was found in Euro-CMR score between the two techniques (0.3 ± 0.7 vs. 0.3 ± 0.5, p > 0.05). Good agreements and correlations were found between the techniques for measuring EDV, ESV, EF, SV, and LV mass. In patients with difficulty in breath-holding or arrhythmia, segmented cine MRI had a significant higher Euro-CMR score (2.3 ± 1.2 vs. 0.4 ± 0.5, p < 0.001). Conclusion: Real-time cine MRI at 3T allowed the assessment of LV volume with high accuracy and showed a significantly better image quality compared to that of segmented cine MRI in patients with difficulty in breath-holding and arrhythmia.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.222-228
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• 2023

This study aimed to analyze the applicability of the improved median filter in positron emission tomography (PET)/magnetic resonance (MR) fusion images based on parallel imaging using generalized autocalibrating partially parallel acquisition (GRAPPA). In this study, a PET/MR fusion imaging system based on a 3.0T magnetic field and ¹⁸F radioisotope were used. An improved median filter that can set a mask of the median value more efficiently than before was modeled and applied to the acquired image. As quantitative evaluation parameters of the noise level, the contrast to noise ratio (CNR) and coefficient of variation (COV) were calculated. Additionally, no-reference-based evaluation parameters were used to analyze the overall image quality. We confirmed that the CNR and COV values of the PET/MR fusion images to which the improved median filter was applied improved by approximately 3.32 and 2.19 times on average, respectively, compared to the noisy image. In addition, the no-reference-based evaluation results showed a similar trend for the noise-level results. In conclusion, we demonstrated that it can be supplemented by using an improved median filter, which suggests the problem of image quality degradation of PET/MR fusion images that shortens scan time using GRAPPA.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.2
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• pp.407-410
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• 1999

Purpose; To find out the best imaging parameters for the diagnosis of disc in MRI imaging. Materials and methods; The diagnostic quality of the disc among the Tl, PD and T2 images of same patients02 joints, 223 images) was compared by visual(I-IV grades) and gray level measurement (pre- and infra-discal area) method. Results; PD images showed best results with 43.7％ of the images belonging to grade III (good) and with statistically significant higher difference of the gray levels at pre- and infra-discal areas. But there were no grade N (excellent) images. Conclusions; PD images are best method among Tl. PD and T2 images in diagnosing the disc but since there were no excellent images further imaging parameters should be studied for better images.

• Journal of Biomedical Engineering Research
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• v.17 no.3
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• pp.305-312
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• 1996

A new three dimensional fractal coding is proposed with a perceptually enhanced matching. Since most of medical images (e.g. computed tomoyaphy or magnetic resonance images) have three dimensional characters, searching regions are extended to adjacent slices. For a perceptually enhanced matching, a high frequency boost filter is used for pre-filtering images to be encoded, and a least mean square error matching is applied to the edge enhanced Images rather than the original images. From simulation with magnetic resonance images($255\times255$, 8bits/pixel), reconstructed images by the proposed compression algorithm show much improved subjective image quality with higher peak signnal-to-noise ratio compared to those by existing fractal coding algorithms at compression ratios of about 10.

• Imaging Science in Dentistry
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• v.51 no.3
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• pp.329-332
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• 2021

A markedly enlarged foramen transversarium was discovered incidentally on a cone-beam computed tomography scan of a 72-year-old male patient who was referred for dental implant placement. Further evaluation with magnetic resonance angiography revealed that the foramen enlargement was caused by a tortuosity in the course of the vertebral artery. This case report highlights the importance of recognizing significant incidental findings on diagnostic images and the potential need for additional imaging as part of the complete interpretative process.