• Proceedings of the KSMRM Conference
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• 1997.10a
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• pp.12-12
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• 1997

• Korean Journal of Radiology
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• v.24 no.5
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• pp.444-453
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• 2023

Objective: Meningeal lymphatic vessels are predominantly located in the parasagittal dural space (PSD); these vessels drain interstitial fluids out of the brain and contribute to the glymphatic system. We aimed to investigate the ability of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in assessing the dynamic changes in the meningeal lymphatic vessels in PSD. Materials and Methods: Eighteen participants (26-71 years; male:female, 10:8), without neurological or psychiatric diseases, were prospectively enrolled and underwent DCE-MRI. Three regions of interests (ROIs) were placed on the PSD, superior sagittal sinus (SSS), and cortical vein. Early and delayed enhancement patterns and six kinetic curve-derived parameters were obtained and compared between the three ROIs. Moreover, the participants were grouped into the young (< 65 years; n = 9) or older (≥ 65 years; n = 9) groups. Enhancement patterns and kinetic curve-derived parameters in the PSD were compared between the two groups. Results: The PSD showed different enhancement patterns than the SSS and cortical veins (P < 0.001 and P < 0.001, respectively) in the early and delayed phases. The PSD showed slow early enhancement and a delayed wash-out pattern. The six kinetic curve-derived parameters of PSD was significantly different than that of the SSS and cortical vein. The PSD washout rate of older participants was significantly lower (median, 0.09; interquartile range [IQR], 0.01-0.15) than that of younger participants (median, 0.32; IQR, 0.07-0.45) (P = 0.040). Conclusion: This study shows that the dynamic changes of meningeal lymphatic vessels in PSD can be assessed with DCE-MRI, and the results are different from those of the venous structures. Our finding that delayed wash-out was more pronounced in the PSD of older participants suggests that aging may disturb the meningeal lymphatic drainage.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.281-282
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• 1998

Recently, there has been growing interest in the assessment of physiological parameters on brain perfusion that provide more information than pure morphologic diagnosis. Quantification of parameters that characterize cerebral micro-circulation with magnetic resonance imaging is of great relevance for clinical application. We determine the local tissue concentration by exponential relationship between the relative signal reduction S(t)/$S_0$ and local tissue concentration of contrast material $C_m(t)$ in dynamic susceptibility contrast enhanced MR imaging. And then we made relative regional blood volume map by calculating the area under the measured concentration-time curves $C_m(t)$ during first pass of paramagnetic contrast material as a preliminary step for perfusion map. These images make it possible to compare the rCBV in different brain regions in one individual at a time. We have it in contemplation to obtain arterial and brain signal time curves simultaneously to make absolute rCBV and perfusion (rCBF) map. These maps may provide the method of comparative investigations of different patients having strong variation in AIF.

• Korean Journal of Radiology
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• v.22 no.7
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• pp.1152-1162
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• 2021

Objective: This study aimed to determine whether there are regional differences in the blood-brain barrier (BBB) permeability of cognitively normal elderly participants and to identify factors influencing BBB permeability with a clinically feasible, 10-minute dynamic contrast-enhanced (DCE) MRI protocol. Materials and Methods: This IRB-approved prospective study recruited 35 cognitively normal adults (26 women; mean age, 64.5 ± 5.6 years) who underwent DCE T1-weighted imaging. Permeability maps (K_trans) were coregistered with masks to calculate the mean regional values. The paired t test and Friedman test were used to compare Ktrans between different regions. The relationships between K_trans and the factors of age, sex, education, cognition score, vascular risk burden, vascular factors on imaging, and medial temporal lobar atrophy were assessed using Pearson correlation and the Spearman rank test. Results: The mean permeability rates of the right and left hippocampi, as assessed with automatic segmentation, were 0.529 ± 0.472 and 0.585 ± 0.515 (K_trans, x 10^-3 min^-1), respectively. Concerning the deep gray matter, the K_trans of the thalamus was significantly greater than those of the putamen and hippocampus (p = 0.007, p = 0.041). Regarding the white matter, the K_trans value of the occipital white matter was significantly greater than those of the frontal, cingulate, and temporal white matter (p < 0.0001, p = 0.0007, p = 0.0002). The variations in K_trans across brain regions were not related to age, cognitive score, vascular risk burden, vascular risk factors on imaging, or medial temporal lobar atrophy in the study group. Conclusion: Our study demonstrated regional differences in BBB permeability (K_trans) in cognitively normal elderly adults using a clinically acceptable 10-minutes DCE imaging protocol. The regional differences suggest that the integrity of the BBB varies across the brains of cognitively normal elderly adults. We recommend considering regional differences in K_trans values when evaluating BBB permeability in patients with neurodegenerative diseases.

• Investigative Magnetic Resonance Imaging
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• v.19 no.2
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• pp.127-130
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• 2015

Direct injection of foreign material, such as liquid paraffin and silicone, into the breast can induce a foreign body granulomatous reaction and fibrosis, resulting in hard, nodular breast masses and architectural distortion that can mimic neoplasm. Conventional methods, including physical examination, mammography, and ultrasonography are of little use to differentiate between foreign body-induced mastopathy and breast cancer. In patients with foreign body injection such as breast augmentation, dynamic contrast enhanced MR imaging is an excellent imaging modality. Here, the authors report the MR imaging and pathological findings of ductal carcinoma in situ (DCIS) with multicystic changes in a 41-year-old woman with a previous history of interstitial mammoplasty by paraffin injection.

• Parasites, Hosts and Diseases
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• v.45 no.2 s.142
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• pp.77-85
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• 2007

Among several diagnostic tools for clonorchiasis (Clonorchis sinensis infection), radiologic examinations are commonly used in clinical practices. During the 2 past decades, many reports regarding imaging findings of clonorchiasis were introduced. The basic imaging finding of clonorchiasis is diffuse dilatation of the peripheral intra-hepatic bile ducts, without dilation of the large intrahepatic or extrahepatic bile ducts. By this finding, however, active clonorchiasis cannot be differentiated from cured infection. Some recent radiologic studies suggested specific findings of active clonorchiasis. Besides direct demonstration of worms, increased periductal echogenicity on sonography and periductal enhancement on dynamic contrast-enhanced CT or MR imaging possibly represent active clonorchiasis. Those images of the liver clonorchiasis are known to be correlated with worm burdens (EPG counts) in their frequency and also severity. The images of cholangiocarcinoma associated with clonorchiasis show both the tumor with obstruction images and diffuse dilatation of the peripheral intrahepatic bile ducts. Radiological images can be a good practical alternative diagnostic method of clonorchiasis.

• 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.

• Korean Journal of Radiology
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• v.22 no.7
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• pp.1021-1033
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• 2021

Objective: To assess the expression of vascular normalization genes in different molecular subtypes of breast cancer and to determine whether molecular subtypes with a higher vascular normalization gene expression can be identified using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI). Materials and Methods: This prospective study evaluated 306 female (mean age ± standard deviation, 50 ± 10 years), recruited between January 2014 and August 2017, who had de novo breast cancer larger than 1 cm in diameter (308 tumors). DCE MRI followed by IVIM DWI studies using 11 different b-values (0 to 1200 s/mm²) were performed on a 1.5T MRI system. The Tofts model and segmented biexponential IVIM analysis were used. For each tumor, the molecular subtype (according to six [I-VI] subtypes and PAM50 subtypes), expression profile of genes for vascular normalization, pericytes, and normal vascular signatures were determined using freshly frozen tissue. Statistical associations between imaging parameters and molecular subtypes were examined using logistic regression or linear regression with a significance level of p = 0.05. Results: Breast cancer subtypes III and VI and PAM50 subtypes luminal A and normal-like exhibited a higher expression of genes for vascular normalization, pericyte markers, and normal vessel function signature (p < 0.001 for all) compared to other subtypes. Subtypes III and VI and PAM50 subtypes luminal A and normal-like, versus the remaining subtypes, showed significant associations with K^trans, k_ep, v_p, and IAUGC_BN90 on DEC MRI, with relatively smaller values in the former. The subtype grouping was significantly associated with D, with relatively less restricted diffusion in subtypes III and VI and PAM50 subtypes luminal A and normal-like. Conclusion: DCE MRI and IVIM parameters may identify molecular subtypes of breast cancers with a different vascular normalization gene expression.

• Investigative Magnetic Resonance Imaging
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• v.23 no.4
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• pp.351-360
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• 2019

Purpose: To investigate noninvasive biomarkers for predicting treatment response in patients with locally advanced HCC who underwent concurrent chemoradiotherapy (CCRTx). Materials and Methods: Thirty patients (55.5 ± 10.2 years old, M:F = 24:6) who underwent CCRTx due to advanced HCC were enrolled. Contrast-enhanced US (CEUS) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) were obtained before and immediately after CCRTx. The third CEUS was obtained at one month after CCRTx was completed. Response was assessed at three months after CCRTx based on RECIST 1.1. Quantitative imaging biomarkers measured with CEUS and MRI were compared between groups. A cutoff value was calculated with ROC analysis. Overall survival (OS) was compared by the Breslow method. Results: Twenty-five patients were categorized into the non-progression group and five patients were categorized into the progression group. Peak enhancement of the first CEUS before CCRTx (PE1) was significantly lower in the non-progression group (median, 18.6%; IQR, 20.9%) than that in the progression group (median, 59.1%; IQR, 13.5%; P = 0.002). There was no significant difference in other quantitative biomarkers between the two groups. On ROC analysis, with a cutoff value of 42.6% in PE1, the non-progression group was diagnosed with a sensitivity of 90.9% and a specificity of 100%. OS was also significantly longer in patients with PE1 < 42.6% (P = 0.014). Conclusion: Early treatment response and OS could be predicted by PE on CEUS before CCRTx in patients with HCC.

• Korean Journal of Radiology
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• v.23 no.6
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• pp.598-614
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• 2022

While ultrasound (US) is considered an important tool for hepatocellular carcinoma (HCC) surveillance, it has limited sensitivity for detecting early-stage HCC. Abbreviated MRI (AMRI) has recently gained popularity owing to better sensitivity in its detection of early-stage HCC than US, while also minimizing the time and cost in comparison to complete contrast-enhanced MRI, as AMRI includes only a few essential sequences tailored for detecting HCC. Currently, three AMRI protocols exist, namely gadoxetic acid-enhanced hepatobiliary-phase AMRI, dynamic contrast-enhanced AMRI, and non-enhanced AMRI. In this study, we discussed the rationale and technical details of AMRI techniques for achieving optimal surveillance performance. The strengths, weaknesses, and current issues of each AMRI protocol were also elucidated. Moreover, we scrutinized previously performed AMRI studies regarding clinical and technical factors. Reporting and recall strategies were discussed while considering the differences in AMRI protocols. A risk-stratified approach for the target population should be taken to maximize the benefits of AMRI and the cost-effectiveness should be considered. In the era of multiple HCC surveillance tools, patients need to be fully informed about their choices for better adherence to a surveillance program.