• Investigative Magnetic Resonance Imaging
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• 제21권1호
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• pp.43-50
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• 2017

Chronic expanding organizing hematoma (CEH) occasionally mimics a soft tissue tumor on MRI, which becomes more problematic in patients with a history of surgical resection for musculoskeletal malignancy. Herein, we present a case of CEH which we were able to differentiate from recurrent tumor through MRI follow-up, including diffusion-weighted imaging (DWI) and dynamic contrast enhanced (DCE) imaging. A 66-year-old male visited our institution under suspicion of recurrent leiomyosarcoma of the thigh, 19 months after surgery and radiation therapy. Due to inconclusive results, three US-guided biopsies and 6 MRI examinations were performed over 2 years. In the end, we could diagnose a CEH using conventional and functional MRI techniques, and it was histopathologically confirmed after surgical resection. A CEH may occur remotely after an initiating event, and it may persist and expand over several years. Functional MR sequences, in addition to conventional sequences, are helpful in differentiating CEH from malignant neoplasms.

• Korean Journal of Radiology
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• 제24권6호
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• pp.553-563
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• 2023

Objective: Functional magnetic resonance imaging (fMRI) and diffusion tensor imaging-derived tractography (DTI-t) contribute to the localization of language areas, but their accuracy remains controversial. This study aimed to investigate the diagnostic performance of preoperative fMRI and DTI-t obtained with a simultaneous multi-slice technique using intraoperative direct cortical stimulation (DCS) or corticocortical evoked potential (CCEP) as reference standards. Materials and Methods: This prospective study included 26 patients (23-74 years; male:female, 13:13) with tumors in the vicinity of Broca's area who underwent preoperative fMRI and DTI-t. A site-by-site comparison between preoperative (fMRI and DTI-t) and intraoperative language mapping (DCS or CCEP) was performed for 226 cortical sites to calculate the sensitivity and specificity of fMRI and DTI-t for mapping Broca's areas. For sites with positive signals on fMRI or DTI-t, the true-positive rate (TPR) was calculated based on the concordance and discordance between fMRI and DTI-t. Results: Among 226 cortical sites, DCS was performed in 100 sites and CCEP was performed in 166 sites. The specificities of fMRI and DTI-t ranged from 72.4% (63/87) to 96.8% (122/126), respectively. The sensitivities of fMRI (except for verb generation) and DTI-t were 69.2% (9/13) to 92.3% (12/13) with DCS as the reference standard, and 40.0% (16/40) or lower with CCEP as the reference standard. For sites with preoperative fMRI or DTI-t positivity (n = 82), the TPR was high when fMRI and DTI-t were concordant (81.2% and 100% using DCS and CCEP, respectively, as the reference standards) and low when fMRI and DTI-t were discordant (≤ 24.2%). Conclusion: fMRI and DTI-t are sensitive and specific for mapping Broca's area compared with DCS and specific but insensitive compared with CCEP. A site with a positive signal on both fMRI and DTI-t represents a high probability of being an essential language area.

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 2002년도 제7차 학술대회 초록집
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• pp.86-86
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• 2002

Purpose： To evaluate the white matter fiber configuration in various developmental CNS anomaly 대상 및 방법： Jubert Syndrome, congenital schizencephaly, callosal agenesis and hemiplegic cerebral palsy patients were evaluated by diffusion tensor MRI. All studies were performed using a 1.5T Philips Gyroscan Intern system. Diffusion weighted imaging was performed using single-shot echo planar imaging, with navigator echo phase correction and SENSE. Diffusion weighting was performed along six independent axes, using diffusion weighting of b=600s/$\textrm{mm}^2$. 128 matrix/zero filled to 256, 23cm FOV, 3mm slice thickness were used for imaging parameters. Data were processed on a Window-2000 PC equipped with IDL and PRIDE (Philips Medical System).

• Investigative Magnetic Resonance Imaging
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• 제26권1호
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• pp.20-31
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• 2022

Purpose: To assess conventional MRI features associated with residual soft-tissue sarcomas following unplanned excision (UPE), and to compare the diagnostic performance of conventional MRI only with that of MRI including diffusion-weighted imaging (DWI) for residual tumors after UPE. Materials and Methods: We included 103 consecutive patients who had received UPE of a soft-tissue sarcoma with wide excision of the tumor bed between December 2013 and December 2019 and who also underwent conventional MRI and DWI in this retrospective study. The presence of focal enhancement, soft-tissue edema, fascial enhancement, fluid collections, and hematoma on MRI including DWI was reviewed by two musculoskeletal radiologists. We used classification and regression tree (CART) analysis to identify the most significant MRI features. We compared the diagnostic performances of conventional MRI and added DWI using the McNemar test. Results: Residual tumors were present in 69 (66.9%) of 103 patients, whereas no tumors were found in 34 (33.1%) patients. CART showed focal enhancement to be the most significant predictor of residual tumors and correctly predicted residual tumors in 81.6% (84/103) and 78.6% (81/103) of patients for Reader 1 and Reader 2, respectively. Compared with conventional MRI only, the addition of DWI for Reader 1 improved specificity (32.8% vs. 56%, 33.3% vs. 63.0%, P < 0.05), decreased sensitivity (96.8% vs. 84.1%, 98.7% vs. 76.7%, P < 0.05), without a difference in diagnostic accuracy (76.7% vs. 74.8%, 72.9% vs. 71.4%) in total and in subgroups. For Reader 2, diagnostic performance was not significantly different between the sets of MRI (P > 0.05). Conclusion: After UPE of a soft-tissue sarcoma, the presence or absence of a focal enhancement was the most significant MRI finding predicting residual tumors. MRI provided good diagnostic accuracy for detecting residual tumors, and the addition of DWI to conventional MRI may increase specificity.

• Investigative Magnetic Resonance Imaging
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• 제26권2호
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• pp.83-95
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• 2022

The purpose of this study was to establish and provide guidelines for the standardized acquisition and interpretation of diffusion-weighted magnetic resonance imaging (DW-MRI) to improve the image quality and reduce the variability of the results interpretation. The standardized protocol includes the use of high-resolution DW-MRI with advanced techniques and post-processing. The aim of the protocol is to increase the effectiveness of the medical image information exchange involved in the construction, activation, and exchange of clinical information for healthcare use. An organized interpretation form could make DW-MRIs' interpretation easier and more familiar. Herein, the authors briefly review the basic principles, optimized image acquisition, standardized interpretation guidelines, false negative and false positive cases of DW-MRI, and provide a standard interpretation form and examples of various cases to help users become more familiar with the DW-MRI.

• 한국멀티미디어학회논문지
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• 제24권5호
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• pp.684-694
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• 2021

Resting-state Functional Magnetic Resonance Imaging(fMRI) data detects the temporal correlations in Blood Oxygen Level Dependent(BOLD) signal and these temporal correlations are regarded to reflect intrinsic cortical connectivity, which is deactivated during attention demanding, non-self referential tasks, called Default Mode Network(DMN). The relationship between fMRI and anatomical connectivity has not been studied in detail, however, the preceded studies have tried to clarify this relationship using Diffusion Tensor Imaging(DTI) and fMRI. These studies use method that fMRI data assists DTI data or vice versa and it is used as guider to perform DTI tractography on the brain image. In this study, we hypothesized that functional connectivity in resting state would reflect anatomical connectivity of DMN and the combined images include information of fMRI and DTI showed visible connection between brain regions related in DMN. In the previous study, functional connectivity was determined by subjective region of interest method. However, in this study, functional connectivity was determined by objective and advanced method through Independent Component Analysis. There was a stronger connection between Posterior Congulate Cortex(PCC) and PHG(Parahippocampa Gyrus) than Anterior Cingulate Cortex(ACC) and PCC. This technique might be used in several clinical field and will be the basis for future studies related to aging and the brain diseases, which are needed to be translated not only functional connectivity, but structural connectivity.

• 대한영상의학회지
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• 제82권1호
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• pp.29-48
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• 2021

확산강조영상은 유방암의 진단과 스크리닝에 있어 독립적 검사 방법으로서의 기대되는 결과를 보여주는 빠른 비조영증강 검사 방법이다. 현재까지의 연구 결과 유방암 진단에 있어 독립적 검사 방법으로서 확산강조영상의 민감도는 역동적 조영증강 검사보다는 낮으나 유방촬영술보다는 높으며, 이로써 유방암 스크리닝에 대한 유용한 대안이 될 수 있을 것으로 보인다. 확산강조영상의 표준화된 영상 획득과 판독을 통해 영상 화질이 개선될 수 있고, 판독 결과의 다양성도 감소할 것으로 기대된다. 또한, 최신 기법과 후처리 기법을 사용한 고해상도 확산강조영상을 시행함으로써 1 cm 미만의 작은 암의 발견율을 증가시킬 수 있고, 가음성 및 가양성 결과를 감소시킬 것으로 보인다. 현재 한국에서 진행 중인 고위험군 여성에서의 확산강조영상 스크리닝에 대한 다기관 연구 결과가 나온다면 독립적 검사로서의 확산강조영상의 사용을 촉진시킬 수 있을 것으로 기대된다.

• Investigative Magnetic Resonance Imaging
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• 제20권4호
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• pp.250-253
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• 2016

Acute Japanese encephalitis (JE) is an endemic viral infectious disease in various parts of Far East and Southeast Asian countries including Korea. Bilateral thalami are the most common involving sites in JE. Other areas including the basal ganglia, substantia nigra, red nucleus, pons, cerebral cortex and cerebellum may be also involved. We report an extremely unusual brain diffusion-weighted MR imaging (DWI) findings in a 53-year-old man with serologically proven JE involving unilateral deep gray matter and temporal lobe, which shows multifocal high signal intensities in left thalamus, left substantia nigra, left caudate nucleus and left medial temporal cortex on T2-weighted image and DWI with iso-intensity on apparent diffusion coefficient (ADC) map.

• Asian Pacific Journal of Cancer Prevention
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• 제16권8호
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• pp.3407-3412
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• 2015

Background: The aim of this study was to evaluate and compare the accuracy of diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC) value, and time-intensity curve (TIC) type analysis derived from dynamic contrast-enhanced MR imaging (DCE-MRI) in differentiating benign from malignant adnexal masses. Materials and Methods: 47 patients with 56 adnexal masses (27 malignant and 29 benign) underwent DWI and DCE-MRI examinations, prior to surgery. DWI signal intensity, mean ADC value, and TIC type were determined for all the masses. Results: High signal intensity on DWI and type 3 TIC were helpful in differentiating benign from malignant adnexal masses (p<0.001). The mean ADC value was significantly lower in malignant adnexal masses (p<0.001). An ADC value< $1.20{\times}10^{-3}mm^2/s$ may be the optimal cutoff for differentiating between benign and malignant tumors. The negative predictive value for low signal intensity on DWI, and type 1 TIC were 100%. The pairwise comparison among the receiver operating characteristic (ROC) curves showed that the area under the curve (AUC) of TIC was significantly larger than the AUCs of DWI and ADC (p<0.001 for comparison of TIC and DWI, p<0.02 for comparison of TIC and ADC value). Conclusions: DWI, ADC value and TIC type derived from DCE-MRI are all sensitive and relatively specific methods for differentiating benign from malignant adnexal masses. By comparing these functional MR techniques, TIC was found to be more accurate than DWI and ADC.

• Investigative Magnetic Resonance Imaging
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• 제25권4호
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• pp.338-344
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• 2021

Solitary fibrous tumors (SFT) are rare mesenchymal tumors that most commonly develop in the pleura; they rarely involve the diaphragm. MRI has not been widely used to evaluate SFTs of the thoracic cavity, though it may be highly useful in assessing local invasion, predicting malignant potential, and helping in the differential diagnosis. However, MRI findings of malignant SFTs of the diaphragmatic pleura have been described in only two cases. We report a rare case of a malignant solitary fibrous tumor of the diaphragmatic pleura in an 82-year-old man. We describe the clinical and characteristic imaging features, including computed tomography, conventional MRI, and diffusion-weighted imaging. Contrast-enhanced MRI is more accurate than is CT in identifying the origin of SFTs, predicting whether they ae benign or malignant, and assessing local invasion. This imaging modality proved helpful in deciding on the treatment strategy for these rare tumors.