• Investigative Magnetic Resonance Imaging
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• 제26권2호
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• pp.125-134
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• 2022

Purpose: The aim of this study was to investigate the change in signal sensitivity over different acquisition start times and optimize the scanning window to provide the maximal signal sensitivity of [1-¹³C]pyruvate and its metabolic products, lactate and alanine, using spatially localized hyperpolarized 3D ¹³C magnetic resonance spectroscopic imaging (MRSI). Materials and Methods: We acquired 3D ¹³C MRSI data from the brain (n = 3), kidney (n = 3), and liver (n = 3) of rats using a 3T clinical scanner and a custom RF coil after the injection of hyperpolarized [1-¹³C]pyruvate. For each organ, we obtained three consecutive 3D ¹³C MRSI datasets with different acquisition start times per animal from a total of three animals. The mean signal-to-noise ratios (SNRs) of pyruvate, lactate, and alanine were calculated and compared between different acquisition start times. Based on the SNRs of lactate and alanine, we identified the optimal acquisition start timing for each organ. Results: For the brain, the acquisition start time of 18 s provided the highest mean SNR of lactate. At 18 s, however, the lactate signal predominantly originated from not the brain, but the blood vessels; therefore, the acquisition start time of 22 s was recommended for 3D ¹³C MRSI of the rat brain. For the kidney, all three metabolites demonstrated the highest mean SNR at the acquisition start time of 32 s. Similarly, the acquisition start time of 22 s provided the highest SNRs for all three metabolites in the liver. Conclusion: In this study, the acquisition start timing was optimized in an attempt to maximize metabolic signals in hyperpolarized 3D ¹³C MRSI examination with [1-¹³C] pyruvate as a substrate. We investigated the changes in metabolic signal sensitivity in the brain, kidney, and liver of rats to establish the optimal acquisition start time for each organ. We expect the results from this study to be of help in future studies.

• Journal of Yeungnam Medical Science
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• 제39권1호
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• pp.53-57
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• 2022

Hepatic hemangiomas infrequently exhibit atypical imaging features, which may cause diagnostic confusion with hepatic malignancies and lead to unnecessary surgery. We report a rare case of multilocular cystic hemangioma of the liver mimicking a mucinous cystic neoplasm of the liver in a 48-year-old female, focusing on computed tomography and magnetic resonance imaging features and their differential diagnosis.

• Investigative Magnetic Resonance Imaging
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• 제23권3호
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• pp.251-258
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• 2019

Purpose: To assess the feasibility of the use of spin-echo echo-planar imaging (SE-EPI) magnetic resonance elastography (MRE) in livers of children and young adults. Materials and Methods: Patients (${\leq}20$ years old) who underwent 3T SE-EPI MRE were included retrospectively. Subjects were divided into three groups according to the purpose of the liver MRI: suspicion of fatty liver or focal fat deposition in the liver (FAT group), liver fibrosis after receiving a Kasai operation from biliary atresia (BA group), and hepatic iron deposition after receiving chemotherapy or transfusions (IRON group). Technical failure of MRE was defined when a stiffness map showed no pixel value with a confidence index higher than 95%, and the patients were divided as success and failure groups accordingly. Clinical findings including age, gender, weight, height, and body mass index and magnetic resonance imaging results including proton density fat fraction (PDFF), $T2^*$, and MRE values were assessed. Factors affecting failure of MRE were evaluated and the image quality in wave propagation image and stiffness map was evaluated using the appropriate scores. Results: Among total 240 patients (median 15 years, 211 patients in the FAT, 21 patients in the BA, and 8 patients in the IRON groups), technical failure was noted in six patients in the IRON group (6/8 patients, 75%), while there were no failures noted in the FAT and BA groups. These six patients had $T2^*$ values ranging from 0.9 to 3.8 ms. The image quality scores were not significantly different between the FAT and BA groups (P > 0.999), while the scores were significantly lower in the IRON group (P < 0.001). Conclusion: The 3T SE-EPI MRE in children and young adults had a high technical success rate. The technical failure was occurred in children with decreased $T2^*$ value (${\leq}3.8ms$) from iron deposition.

• Investigative Magnetic Resonance Imaging
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• 제16권1호
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• pp.76-80
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• 2012

간 내 호산구 침윤은 드문 질환이 아니며 문맥기의 컴퓨터 단층촬영에서 대게 작고, 다수며, 형태가 명백하지 않으며 타원형 혹은 둥근 형태의 낮은 감쇠 병변으로 발현된다. 저자들은 간 내 호산구 침윤의 비특이적 소견의 간 분절침윤 형태의 소견을 보고하고자 한다.

• Investigative Magnetic Resonance Imaging
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• 제19권1호
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• pp.47-51
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• 2015

Sarcomatous Intrahepatic cholangiocarcinoma is a rare but an aggressive variant of cholangiocarcinoma with a very poor prognosis. A 79-year-old man was admitted to our hospital because of incidentally found liver mass. Magnetic resonance imaging (MRI) revealed well-defined hypointense mass on T1WI and heterogeneous hyperintense mass on T2WI. Gd-EOB-DTPA enhanced study shows peripheral rim-like enhancement in arterial phase and progressive concentric filling of contrast in delayed phase. And mass shows significant enhancement in hepatobiliary phase. The pathologic diagnosis was intrahepatic cholangiocarcinoma with sarcomatous change.

• Investigative Magnetic Resonance Imaging
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• 제22권3호
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• pp.177-181
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• 2018

Intraperitoneal metastatic hepatocellular carcinoma (HCC) is uncommon. Although rare, it can spontaneously rupture and cause hemoperitoneum similar to primary HCC in the liver. We present a case of intraperitoneal metastatic HCC that had spontaneously ruptured and appeared as an irregularly margined hemorrhagic mass with T1 high and T2 dark signal intensities on magnetic resonance imaging. Ruptured HCC is a life-threatening emergency with high mortality rate. Spontaneously ruptured intraperitoneal metastatic HCC should be considered if a patient with a history of HCC presents with acute abdomen, although rare.

• Investigative Magnetic Resonance Imaging
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• 제13권2호
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• pp.213-217
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• 2009

간에 생기는 단발성 괴사성 결절은 매우 드문 양성 질환으로 대개 아무 증상 없이 우연히 발견되고, 간에서 생길 수 있는 여러 가지 단발성 병변과의 감별을 필요로 하며, 특히 악성 종양의 병기 결정에 있어서 간내 전이암과 구별하는 것은 매우 중요하다고 알려져 있다. 영상의학적으로 간의 단발성 괴사성 결절은 조영증강이 얼거나 미약한 주변부 조영증강을 보이는 경계가 좋은 간내 결절로 보고되고 있다. 하지만 단발성 괴사성 결절이 영상에서 과녁 모양으로 보이는 경우는 지금까지 보고된 바 없으며, 특히 고자장의 자기 공명 영상과 양성자 방출 단층 촬영 소견이 보고된 경우도 전무하다. 이에 저자들은 조기 위암 환자에서 과녁 모양으로 보여 전이암과 감별이 어려웠던 간내 단발성 결절을 경험하여 이의 다양한 영상 소견을 보고하고자 하며, 병리학적 소견과 이에 대한 문헌 고찰을 통해 원인을 알아 보고자 하였다.

• Investigative Magnetic Resonance Imaging
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• 제22권2호
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• pp.123-130
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• 2018

An ampulla of Vater neuroendocrine tumor (AOV-NET) is a rare subset of gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Very few studies have been undertaken regarding MRI findings of an AOV-NET. We report on a case of a 59-year-old woman diagnosed with an AOV-NET with liver and lymph node metastasis, with an emphasis on the MRI findings. This case shows rare and precious typical MRI findings of an AOV-NET. The MRI visualized the AOV-NET very well and is helpful for the differentiation of an AOV-NET from other tumors in the ampullary area as well as with treatment planning.

• Investigative Magnetic Resonance Imaging
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• 제21권2호
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• pp.71-81
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• 2017

Purpose: To compare three, motion-resistant, T1-weighted MR sequences on the hepatobiliary phase for gadoxetic acid-enhanced MR imaging of the liver. Materials and Methods: In this retrospective study, 79 patients underwent gadoxetic acid-enhanced, 3T liver MR imaging. Fifty-nine were examined using a standard protocol, and 20 were examined using a motion-resistant protocol. During the hepatocyte-specific phase, three MR sequences were acquired: 1) gradient recalled echo (GRE) with controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA); 2) radial GRE with the interleaved angle-bisection scheme (ILAB); and 3) radial GRE with golden-angle scheme (GA). Two readers independently assessed images with motion artifacts, streaking artifacts, liver-edge sharpness, hepatic vessel clarity, lesion conspicuity, and overall image quality, using a 5-point scale. The images were assessed by measurement of liver signal-to-noise ratio (SNR), and tumor-to-liver contrast-to-noise ratio (CNR). The results were compared, using repeated post-hoc, paired t-tests with Bonferroni correction and the Wilcoxon signed rank test with Bonferroni correction. Results: In the qualitative analysis of cooperative patients, the results for CAIPIRINHA had significantly higher ratings for streak artifacts, liver-edge sharpness, hepatic vessel clarity, and overall image quality as compared to, radial GRE, (P < 0.016). In the imaging of uncooperative patients, higher scores were recorded for ILAB and GA with respect to all of the qualitative assessments, except for streak artifact, compared with CAIPIRINHA (P < 0.016). However, no significant differences were found between ILAB and GA. For quantitative analysis in uncooperative patients, the mean liver SNR and lesion-to-liver CNR with radial GRE were significantly higher than those of CAIPIRINHA (P < 0.016). Conclusion: In uncooperative patients, the use of the radial GRE sequence can improve the image quality compared to GRE imaging with CAIPIRINHA, despite the data acquisition methods used. The GRE imaging with CAIPIRINHA is applicable for patients without breath-holding difficulties.

• Investigative Magnetic Resonance Imaging
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• 제16권2호
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• pp.173-176
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• 2012

본 저자들은 우측 부신에서 발생한 갈색세포종과 인접한 간에서 보이는 국소적인 조영 증강의 영상의학적 소견을 보고하고자 한다. 전산화단층촬영과 자기공명영상의 동맥기 영상에서 인접한 간조직에 국소적인 강한 조영증강이 보였다. 그러나 지연기 영상에서 병변은 정상 간조직과 동일한 감쇄를 보여 잘 구분되지 않았다. 또한 병변은 자기공명 T1, T2 강조 영상에서도 비정상적인 신호강도를 보이지 않았으며 정상 조직과 구분되어 보이지 않았다. 이 조영증강되는 간의 병소는 부신절제술을 시행한지 수개월 후 다시 시행한 수술 후 전산화 단층촬영에서는 저절로 소실되어 보이지 않았다.