• Clinical and Experimental Pediatrics
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• v.55 no.10
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• pp.397-402
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• 2012

Pelizaeus-Merzbacher disease (PMD) is a rare, X-linked recessive disorder characterized by dysmyelination in the central nervous system. PMD results from deletion, mutation, or duplication of the proteolipid protein gene (PLP1) located at Xq22, leading to the failure of axon myelination by oligodendrocytes in the central nervous system. PMD may be suspected when there are clinical manifestations such as nystagmus, developmental delays, and spasticity, and genetic analysis can confirm the diagnosis. Further diagnostic manifestations of the disease include a lack of myelination on brain magnetic resonance (MR) imaging and aberrant N-acetyl aspartate (NAA) and choline concentrations that reflect axonal and myelination abnormalities on phroton MR spectroscopy. We report 5 cases of PMD (in 1 girl and 4 boys). PLP1 duplication was detected in 2 patients. Brain MR analyses and MR spectroscopy were performed for all the patients. The brain MR images showed white matter abnormalities typical of PMD, and the MR spectroscopic images showed diverse patterns of NAA, creatinine, and choline concentrations. We propose that MR spectroscopic analysis of metabolic alterations can aid the PMD diagnosis and can contribute to a better understanding of the pathogenesis of the disease.

• Journal of Veterinary Clinics
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• v.35 no.6
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• pp.315-318
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• 2018

A 13-year-old spayed female Beagle dog was referred with high intraocular pressure, hyperemia, and exophthalmos of the left eye and underwent ultrasound, which revealed a mass in the ciliary body of the left eye. Magnetic resonance (MR) imaging was ordered to evaluate invasion of surrounding structures and metastasis to the brain via the optic nerve. On MR imaging, a single, well-defined, smoothly marginated, triangular-to-oval-shaped mass was found. The mass was hyperintense on T1-weighted images and hypointense on T2-weighted images, similar to a previous case of ocular melanoma. The mass originated from the ciliary body and extended from the anterior chamber to the posterior chamber. Slight enhancement was observed in the mass. There was no evidence of invasion into surrounding structures or the optic nerve, and no sign of metastasis to the brain. The mass was histopathologically diagnosed as benign uveal melanocytoma.

• Investigative Magnetic Resonance Imaging
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• v.17 no.2
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• pp.149-153
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• 2013

Detection of cerebrospinal fluid leakage or exact localization of leakage site after spinal surgery is difficult on conventional imaging studies. We report two patients with surgery-related spinal CSF leakage detected on magnetic resonance (MR) myelography. They presented with severe headache after spinal surgeries, lumbar discectomy and excision of spinal meningioma, respectively. The sites of spinal CSF leakage in the patients were detected accurately on MR myelography, and the patients recovered from the postoperative CSF leakage after being treated with an epidural blood patch or reoperation. MR myelography may be effective in demonstrating the exact site of surgery-related spinal CSF leakage.

• Journal of Korean Neurosurgical Society
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• v.61 no.5
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• pp.582-591
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• 2018

Objective : To evaluate the magnetic resonance (MR) imaging features that have a statistically significant association with the need for a tracheostomy in patients with cervical spinal cord injury (SCI) during the acute stage of injury. Methods : This study retrospectively reviewed the clinical data of 130 patients with cervical SCI. We analyzed the factors believed to increase the risk of requiring a tracheostomy, including the severity of SCI, the level of injury as determined by radiological assessment, three quantitative MR imaging parameters, and eleven qualitative MR imaging parameters. Results : Significant differences between the non-tracheostomy and tracheostomy groups were determined by the following five factors on multivariate analysis : complete SCI (p=0.007), the radiological level of C5 and above (p=0.038), maximum canal compromise (MCC) (p=0.010), lesion length (p=0.022), and osteophyte formation (p=0.015). For the MCC, the cut-off value was 46%, and the risk of requiring a tracheostomy was three times higher at an interval between 50-60% and ten times higher between 60-70%. For lesion length, the cut-off value was 20 mm, and the risk of requiring a tracheostomy was two times higher at an interval between 20-30 mm and fourteen times higher between 40-50 mm. Conclusion : The American Spinal Injury Association grade A, a radiological injury level of C5 and above, an MCC ${\geq}50%$, a lesion length ${\geq}20mm$, and osteophyte formation at the level of injury were considered to be predictive values for requiring tracheostomy intervention in patients with cervical SCI.

• Proceedings of the KSMRM Conference
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• 2007.10a
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• pp.52-53
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• 2007

• Proceedings of the KSMRM Conference
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• 1999.04a
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• pp.43-54
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• 1999

Protocol이란 Dorland의 의학사전에 의하면 "어떤 술기의 절차에 대한 명백하고 상세한 계획서(an explicit detailed plan of a procedure)"로 정의된다. 그래서 liver MR imaging protocol은 간에 발생한 병적 문제를 해결하기 위해서, 자기공명영상술을 실시하는 구체적이고 세부적인 지침서를 말하게 된다. 그러나 현실적으로 병원에 따라 imaging protocol은 조금씩 다르다. 왜냐하면 MR장비가 다르고, 적절한 펄스파형(pulse sequence)에 대한 통일된 안이 없기 때문이다. 자기공명영상술은 지금도 계속해서 빠르게 발전하고 있기 때문에, 현재 통용되는 영상 술기에 대한 자세한 지침은 곧 소용이 없게 된다. 그래서 본 소고에서는 간의 MR 영상화와 병변의 특성화에 대한 기본 적인 면에 더욱 중점을 두고 기술하고자 한다. 기술하고자 한다.

• Investigative Magnetic Resonance Imaging
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• v.20 no.2
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• pp.114-119
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• 2016

We report a case of vegetation in a 4-year-old female with infective endocarditis, diagnosed by late gadolinium-enhanced (LGE) cardiovascular magnetic resonance (CMR) imaging. The patient had a history of primary closure for ventricular septal defect and presented with mild febrile sensation. No remarkable clinical symptoms or laboratory findings were noted; however, transthoracic echocardiography demonstrated a 14 mm highly mobile homogeneous mass in the right ventricle. On LGE CMR imaging, the mass showed marginal rim enhancement, which suggested the diagnosis of vegetation rather than thrombus. The extracellular volume fraction (${\geq}42%$) of the lesion was higher than that of normal myocardium. Based on the patient's clinical history of congenital heart disease and pathologic confirmation of the lesion, a diagnosis of infective endocarditis with vegetation was made.

• Journal of Magnetics
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• v.22 no.2
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• pp.220-226
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• 2017

SNR (signal to ratio) is a criterion for providing objective information for evaluating the performance of a magnetic resonance imaging device, and is an important measurement standard for evaluating the quality of MR (Magnetic Resonance) image. The purpose of our study is to evaluate the correct SNR measurement for multi-channel coil and parallel imaging. As a result of research, we found that both T1 and T2 weighted images show the narrowest confidence interval of the method recommended by NEMA (The National Electrical manufacturers Association) 1 having a single measurement method, whereas the ACR (American College of Radiology) measurement method using a multi-channel coil and a parallel imaging technique shows the widest confidence interval. There is a significance in that we quantitatively verified the inaccurate problems of a signal to noise ratio using a ACR measurement method when using a multi-channel coil and a parallel imaging technique of which method does not satisfy the preconditions that researchers could overlook.

• Investigative Magnetic Resonance Imaging
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• v.12 no.2
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• pp.170-177
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• 2008

Purpose : To evaluate usefulness of MR imaging after serial brain US in the high-risk neonates before discharge of the neonatal intensive care unit. Materials and Methods : Retrospective comparison of 412 US and 121 MR scans in 121 neonates and young infants were performed. Grading of germinal matrix/intraventricular hemorrhage (GMH/IVH) was performed and presence of intracranial hemorrhage other than GMH/IVH and parencyma lesions was also analyzed. Results : Among the 242 lateral ventricles, Seven GMH and 46 IVH were additionally detected by MRI. On the other hand, 30 GMH were only detected by US. US demonstrated Grade 1/2/3/4 GMH/IVH in 24/8/13/0 ventricles each, while each grades were identified in 3, 49, 10, 2 ventricles on MR images. Other intracranial lesions additionally detected on MR images were cerebral hemorrhage (n=4), cerebellar hemorrhage (n=4), extraaxial hemorrhage (n=8), diffuse excessive signal change of the white matter (n=72), non-cavitary lesion (n=4), encephalomalacia (n=2), and ventriculomegaly (n=5). Conclusion : MR imaging could be an excellent complimentary study after serial brain US for additional detection of the intracranial pathology, particularly IVH and white matter lesions, though US would be better in follow-up of GMH in some neonates.

• Investigative Magnetic Resonance Imaging
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• v.17 no.3
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• pp.181-191
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• 2013

Purpose : To evaluate the usefulness of in vivo magnetic resonance (MR) imaging for tracking intravenously injected superparamagnetic iron oxide (SPIO)-labeled human umbilical vein endothelial cells (HUVECs) in an acute renal failure (ARF) rat model. Materials and Methods: HUVECs were labeled with SPIO and poly-L-lysine (PLL) complex. Relaxation rates at 1.5-T MR, cell viability, and labeling stability were assessed. HUVECs were injected into the tail vein of ARF rats (labeled cells in 10 rats, unlabeled cells in 2 rats). Follow-up serial $T2^*$-weighted gradient-echo MR imaging was performed at 1, 3, 5 and 7 days after injection, and the MR findings were compared with histologic findings. Results: There was an average of $98.4{\pm}2.4%$ Prussian blue stain-positive cells after labeling with SPIOPLL complex. Relaxation rates ($R2^*$) of all cultured HUVECs at day 3 and 5 were not markedly decreased compared with that at day 1. The stability of SPIO in HUVECs was maintained during the proliferation of HUVECs in culture media. In the presence of left unilateral renal artery ischemia, $T2^*$-weighted MR imaging performed 1 day after the intravenous injection of labeled HUVECs revealed a significant signal intensity (SI) loss exclusively in the left renal outer medulla regions, but not in the right kidney. The MR imaging findings at days 3, 5 and 7 after intravenous injection of HUVECs showed a SI loss in the outer medulla regions of the ischemically injured kidney, but the SI progressively recovered with time and the right kidney did not have a significant change in SI in the same period. Upon histologic analysis, the SI loss on MR images was correspondent to the presence of Prussian blue stained cells, primarily in the renal outer medulla. Conclusion: MR imaging appears to be useful for in vivo monitoring of intravenously injected SPIO-labeled HUVECs in an ischemically injured rat kidney.