• Journal of Radiation Industry
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• v.10 no.4
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• pp.193-198
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• 2016

Perfusion magnetic resonance image of biological mechanism are independent of magnetic field strength in hyper acute ischemic stroke. 3.0 T magnetic field, however, does affect the SNRs (signal to noise ratio) and artifacts of PMRI (perfusion magnetic resonance image), which basically will influence the quantitative of PMRI. In this study, the effects of field strength on PMRI are analyzed. The effects of the diseases also are discussed. PMRI in WM(white matter), GM (gray matter), hyper acute ischemic stroke were companied with 1.5 T and 3.0 T on SNR. PMRI also was compared to the SI difference after setting ROI(region of interest) in left and right side of the brain. In conclusion, the SNRs and SI of the 3.0 T PMRI showed higher than those at 1.5 T. In summary, PMRI studies at 3.0 T is provided significantly improved perfusion evaluation when comparing with 1.5 T.

• Investigative Magnetic Resonance Imaging
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• v.21 no.2
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• pp.106-108
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• 2017

The perfusion change in acute symptomatic hypoglycemic encephalopathy (ASHE) is not well known. We present the perfusion-weighted imaging of a patient with ASHE. The area of diffusion-weighted imaging abnormalities and adjacent normal-appearing white matter showed increased cerebral blood volume and flow, and shortening of time-to-peak.

• Investigative Magnetic Resonance Imaging
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• v.23 no.2
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• pp.157-161
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• 2019

In this study, we report arterial spin labelling perfusion, proton MR spectroscopy and susceptibility-weighted MR findings of acute necrotizing encephalopathy in a child with rotavirus infection.

• Investigative Magnetic Resonance Imaging
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• v.21 no.2
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• pp.82-90
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• 2017

Purpose: This study investigated the MRI, MR angiography (MRA) and MR perfusion findings of seizure-related cerebral cortical lesions during the periictal period. Materials and Methods: From a retrospective review of the institutional database between 2011 and 2014, a total of 21 patients were included in this study. Two radiologists assessed periictal MRI, including MRA and MR perfusion, in patients with seizure-related cortical lesions. The parameters examined include: location of cortical abnormality, multiplicity of the affected cortical region, cerebral vascular dilatation, perfusion abnormality and other parenchymal lesions. Results: All patients showed T2 hyperintense cerebral cortical lesions with accompanying diffusion restriction, either unilateral (18/21, 85.7%) or bilateral (3/21, 14.3%). Of the 21 patients enrolled, 10 (47.6%) had concurrent T2 hyperintense thalamic lesions, and 10 (47.6%) showed hippocampal involvement. Of the 17 patients (81%) who underwent MRA, 13 (76.5%) showed vascular dilatation with increased flow signal in the cerebral arteries of the affected cortical regions. On MR perfusion, all 5 patients showed cortical hyperperfusion, corresponding to the region of cortical abnormalities. Conclusion: Seizure-related cerebral cortical lesions are characterized by T2 and diffusion hyperintensities, with corresponding cerebral hyperperfusion and vascular dilatation. These findings can be helpful for making an accurate diagnosis in patients with seizure.

• Investigative Magnetic Resonance Imaging
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• v.15 no.2
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• pp.91-101
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• 2011

Perfusion magnetic resonance imaging (pMRI) is a special technique for evaluation of blood flow. Exogenous pMRI methods which are dynamic susceptibility contrast (DSC) and dynamic contrast-enhanced (DCE) use an intravenous bolus injection of paramagnetic contrast agent. In contrast, an endogenous pMRM method which is arterial spin labeling (ASL) use diffusible blood in body. In order to scan pMRI in human, technical optimizations are very important according to disease conditions. For examples, DSC is popularly used in patients with acute stroke due to its short scan time, while DSC or DCE provides the various perfusion indices for patients with tumor. ASL is useful for children, women who are expected to be pregnant, and in patients with kidney diseases which are problematic in nephrogenic systemic fibrosis (NSF). Perfusion MRI does not require any injection of radioisotopes. We expect that demand for perfusion MRI will be higher in evaluating drug efficacy and other treatment effects.

• Investigative Magnetic Resonance Imaging
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• v.22 no.1
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• pp.56-60
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• 2018

Therapeutic hypothermia in cardiac arrest patients is associated with favorable outcomes mediated via neuroprotective mechanisms. We report a rare case of a 32-year-old male who demonstrated complete recovery of signal changes on perfusion-weighted imaging after therapeutic hypothermia due to cardiac arrest. Brain MRI with perfusion-weighted imaging, performed three days after ending the hypothermia therapy, showed a marked decrease in relative cerebral blood flow (rCBF) and delay in mean transit time (MTT) in the bilateral basal ganglia, thalami, brain stem, cerebellum, occipitoparietal cortex, and frontotemporal cortex. However, no cerebral ischemia was not noted on diffusion-weighted imaging (DWI) or fluid-attenuated inversion recovery (FLAIR) sequences. A follow-up brain MRI after one week showed complete resolution of the perfusion deficit and the patient was discharged without any neurologic sequelae. The mechanism and interpretation of the perfusion changes in cardiac arrest patients treated with therapeutic hypothermia are discussed.

• Proceedings of the KSMRM Conference
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• 2006.11a
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• pp.66-66
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• 2006

• Proceedings of the Korean Society of Medical Physics Conference
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• 2006.08a
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• pp.36-36
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• 2006

• Proceedings of the KSMRM Conference
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• 2000.11a
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• pp.53-54
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• 2000

• Investigative Magnetic Resonance Imaging
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• v.22 no.2
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• pp.131-134
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• 2018

Susceptibility-weighted imaging (SWI) is well known for detecting the presence of hemorrhagic transformation, microbleeds and the susceptibility of vessel signs in acute ischemic stroke. But in some cases, it can provide the tissue perfusion state as well. We describe a case of a patient with hyperacute ischemic infarction that had a slightly hypodense, patchy lesion at the left thalamus on the initial SWI, with a left proximal posterior cerebral artery occlusion on a magnetic resonance (MR) angiography and delayed time-to-peak on an MR perfusion performed two hours after symptom onset. No obvious abnormal signals at any intensity were found on the initial diffusion-weighted imaging (DWI). On a follow-up MR image (MRI), an acute ischemic infarction was seen on DWI, which is the same location as the lesion on SWI. The hypointensity on the initial SWI reflects the susceptibility artifact caused by an increased deoxyhemoglobin in the affected tissue and vessels, which reflects the hypoperfusion state due to decreasing arterial flow. It precedes the signal change on DWI that reflects a cytotoxic edema. This case highlights that, in some hyperacute stages of ischemic stroke, hypointensity on an SWI may be a finding before the hyperintensity is seen on a DWI.