• Korean Journal of Radiology
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• 제1권4호
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• pp.185-190
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• 2000

Objective: To document the imaging findings of hepatic cavernous hemangioma detected in cirrhotic liver. Materials and Methods: The imaging findings of 14 hepatic cavernous hemangiomas in ten patients with liver cirrhosis were retrospectively analyzed. A diagnosis of hepatic cavernous hemangioma was based on the findings of two or more of the following imaging studies: MR, including contrast-enhanced dynamic imaging (n = 10), dynamic CT (n = 4), hepatic arteriography (n = 9), and US (n = 10). Results: The mean size of the 14 hepatic hemangiomas was 0.9 (range, 0.5-1.5) cm in the longest dimension. In 11 of these (79%), contrast-enhanced dynamic CT and MR imaging showed rapid contrast enhancement of the entire lesion during the early phase, and hepatic arteriography revealed globular enhancement and rapid filling-in. On contrast-enhanced MR images, three lesions (21%) showed partial enhancement until the 5-min delayed phases. US indicated that while three slowly enhancing lesions were homogeneously hyperechoic, 9 (82%) of 11 showing rapid enhancement were not delineated. Conclusion: The majority of hepatic cavernous hemangiomas detected in cirrhotic liver are small in size, and in many, hepatic arteriography and/or contrast-enhanced dynamic CT and MR imaging demonstrates rapid enhancement. US, however, fails to distinguish a lesion of this kind from its cirrhotic background.

• 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.

• Korean Journal of Radiology
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• 제2권4호
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• pp.210-215
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• 2001

Objective: To investigate the efficacy of gadobenate dimeglumine (GdBOPTA) enhanced MR imaging for the detection of liver lesions in patients with primary malignant hepatic neoplasms. Materials and Methods: Thirty-one patients with histologically proven primary malignancy of the liver were evaluated before and after administration of GdBOPTA at dose 0.05 or 0.10 mmol/kg. T1-weighted spin echo (T1W-SE) and gradient echo (T1W-GRE) images were evaluated for lesion number, location, size and confidence by three off-site independent reviewers and the findings were compared to reference standard imaging (intraoperative ultrasound, computed tomography during arterial portography or lipiodol computed tomography). Results were analyzed for significance using a two-sided McNemar's test. Results: More lesions were identified on Gd-BOPTA enhanced images than on unenhanced images and there was no significant difference in lesion detection between either concentration. The largest benefit was in detection of lesions under 1 cm in size (7 to 21, 9 to 15, 16 to 18 for reviewers A, B, C respectively). In 68% of the patients with more than one lesion, Gd-BOPTA increased the number of lesions detected. Conclusion: Liver MR imaging after Gd-BOPTA increases the detection of liver lesions in patients with primary malignant hepatic neoplasm.

• Korean Journal of Radiology
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• 제25권1호
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• pp.24-32
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• 2024

Despite improvements in operative techniques and perioperative care, post-hepatectomy liver failure (PHLF) remains the most serious cause of morbidity and mortality after surgery, and several risk factors have been identified to predict PHLF. Although volumetric assessment using imaging contributes to surgical simulation by estimating the function of future liver remnants in predicting PHLF, liver function is assumed to be homogeneous throughout the liver. The combination of volumetric and functional analyses may be more useful for an accurate evaluation of liver function and prediction of PHLF than only volumetric analysis. Gadoxetic acid is a hepatocyte-specific magnetic resonance (MR) contrast agent that is taken up by hepatocytes via the OATP1 transporter after intravenous administration. Gadoxetic acid-enhanced MR imaging (MRI) offers information regarding both global and regional functions, leading to a more precise evaluation even in cases with heterogeneous liver function. Various indices, including signal intensity-based methods and MR relaxometry, have been proposed for the estimation of liver function and prediction of PHLF using gadoxetic acid-enhanced MRI. Recent developments in MR techniques, including high-resolution hepatobiliary phase images using deep learning image reconstruction and whole-liver T1 map acquisition, have enabled a more detailed and accurate estimation of liver function in gadoxetic acid-enhanced MRI.

• Korean Journal of Radiology
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• 제2권3호
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• pp.151-158
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• 2001

Objective: To determine the ability of MR imaging to detect the pathological changes occurring in radiofrequency (RF) thermal lesions and to assess its accuracy in revealing the extent of tissue necrosis. Materials and Methods: Using an RF electrode, thermal lesions were created in the livers of 18 rabbits. The procedure involved three phases. In the acute phase, six animals were killed the day after performing thermal ablation with RF energy, and two on day 3. In the subacute and chronic phases, eight rabbits underwent percutaneous hepatic RF ablation. After performing MR imaging, two animals were sacrificed at 1, 2, 4, and 7 weeks after the procedure, and MRpathologic correlation was performed. Results: In the acute phase, the thermal ablation lesions appeared at gross examination as well-circumscribed, necrotic areas, representing early change in the coagulative necrosis seen at microscopic examination. They were hypointense on T2-weighted images, and hyperintense on T1-weighted images. Gadolinium-enhanced MR imaging showed that a thin hyperemic rim surrounded the central coagulative necrosis. In the subacute phase, ablated lesions also showed extensive coagulative necrosis and marked inflammation at microscopic examination. Beyond two weeks, the lesions showed gradual resorption of the necrotic area, with a peripheral fibrovascular rim. The size of lesions measured by MR imaging correlated well with the findings at gross pathologic examination. Conclusion: MR imaging effectively demonstrates the histopathological tissue change occurring after thermal ablation, and accurately determines the extent of the target area.

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 1999년도 춘계학술대회 제3차 심포지움
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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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• 제23권1호
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• pp.1-16
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• 2019

Dynamic contrast enhanced (DCE) magnetic resonance (MR) imaging plays an important role in non-invasive detection and characterization of primary and metastatic lesions in the liver. Recently, efforts have been made to improve spatial and temporal resolution of DCE liver MRI for arterial phase imaging. Review of recent publications related to arterial phase imaging of the liver indicates that there exist primarily two approaches: breath-hold and free-breathing. For breath-hold imaging, acquiring multiple arterial phase images in a breath-hold is the preferred approach over conventional single-phase imaging. For free-breathing imaging, a combination of three-dimensional (3D) stack-of-stars golden-angle sampling and compressed sensing parallel imaging reconstruction is one of emerging techniques. Self-gating can be used to decrease respiratory motion artifact. This article introduces recent MRI technologies relevant to hepatic arterial phase imaging, including differential subsampling with Cartesian ordering (DISCO), golden-angle radial sparse parallel (GRASP), and X-D GRASP. This article also describes techniques related to dynamic 3D image reconstruction of the liver from golden-angle stack-of-stars data.

• Investigative Magnetic Resonance Imaging
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• 제1권1호
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• pp.142-147
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• 1997

목적: 호흡정지 간 자기공영상에서 국소 간 병변을 발견함에 있어 동위상(inphase) 방식과 역위상(opposed-phase) 방식의 fast multiplanar spoiled gradient recalled(FMPSPGR) 영상간의 효율성을 비교하고자 하였다. 대상 및 방법: 다른 검사를 통해 국소 간 병변이 발견되었거나 의심되었던 45명의 환자의 78개의 병변에 대한 고속경사에코대열의 동위상과 역위상 영상을 비교하였다. 병변 발견률을 평가하기 위해 세 명의 사전 정보 없는 판독의가 독립적으로 영상을 검토하였다. 간의 신호대잡음비, 병변과 간의 대조대잡음비 및 간과 비장 간 대조대잡음비를 비교하였다. 세 명의 동의에 의해 어느 대열에서 영상의 질이 더 나은지 결정하였다. 결과: 역위상 영상에서 판독의 1, 2, 3이 각각 61(78%), 61(78%), 및 63(89%)개의 병변을 정확히 발견하였다. 동위상 영상에서 각 판독의가 66(85%), 65(83%) 및 65(93%)개의 병변을 발견하였다. 두 영상을 조합하였을 때, 71(91%), 69(88%) 및 76(97%)개의 병변이 각각 발견되었다. 간세포암이 증례에서 간-병변간 대조대잡음비는 역위상 영상에서 더 컸으나(p<0.05), 다른 병변에서의 의미 있는 차이는 보이지 않았다. 간-비장간 대조잡음비는 역위상 영상에서 높았으나(p<0.1), 간의 신호대잡음비는 동위상 영상에서 더 높았다. 결론: 국소적 간 병변을 놓치지 않고 발견 하기 위새서는 동위상 영상과 역위상 영상을 모두 이용하는 것이 바람직하다.

• 대한방사성의약품학회지
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• 제3권1호
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• pp.25-31
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• 2017

Liposomes are defined as spherical, self-closed structures formed by lipid bilayers containing aqueous phase. Most liposomes are composed of various amphipathic lipids such as phospholipids and cholesterol. We used amphipathic lipids (DPPC, DPPG) as liposome components and prepared around 100 nm liposomes by standard extrusion method. Nuclear/MR dual imaging agents based on liposome platform were prepared by adding radioactive $^{131}I$-HIB (hexadecyl-4-tributylstannylbenzoate) and Gd-DTPA into liposome bilayer and inside liposome, respectively. Gamma camera and MR imaging both showed signal increases in liver.

• Investigative Magnetic Resonance Imaging
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• 제5권1호
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• pp.43-48
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• 2001

목적: 방사성 등위원소인 Holmium-166을 가토 간 실질 내에 경피적 주입한 후 나타나는 변화에 대한 조직학적 소견과 MR영상 소견을 알아보고자 하였다. 대상 및 방법: 12예의 가토의 간 실질 내에 Holmium-166 방사성 등위원소 10∼25 mCi를 초음파 유도하에 경피적 주입 후, MR 영상을 시행하기 전에 사망하지 않은 8예의 가토 중 4예는 급성기 (1-2주)에, 나머지 4예는 아급성기 (3-4주)에 MR 영상을 시행한 후 희생시켜, 조직표본을 얻었으며 , MR 영상을 시행하기 전에 사망한 4예 중 1예는 급성기에, 3예는 아급성기에 조직표본만을 검사하였다. 결과 괴사부위는 중심부의 액화괴사와 주변부의 응괴 괴사(coagulative necrosis). 과립성 입자의 침착, 출혈 등의 변화를 보였으며, 테두리에는 육아조직의 형성과 섬유화가 관찰되었는데, 섬유화는 급성기보다 아급성기에서 현저하였다. Holmium-166 주입양과 간 실질의 괴사 면적과는 비례하는 경향을 보였다. MR영상에서 괴사의 중앙부는 T1 강조영상에서는 저신호, T2 강조영상에서는 고신호를 나타냈으며, 조영후 역동적 영상에서는 조영증강이 되지 않았다 주변부는 T1 강조영상에서는 동등 신호 또는 약간 저신호, T2 강조영상에서는 저신호를 보였으며, 조명후 역동적 영상에서는 지 연기에서 약한 조영 증강이 말초부에서 관찰되었다. 테두리는 T1 강조영상에서는 저신호, T2 강조영상에서는 저신호, 조명후 역동적 영상에서는 초기에 약간 조영 증강하고, 후기에는 좀더 조영증강이 강해지는 소견을 보였다. 결론: 정상 간조직에 경피적으로 Holmium-166을 주입하였을 때, 조직학적으로 중앙부는 액화괴사, 주변부는 응고괴사, 테두리에는 육아 조직, 섬유화, 출혈과 과립성 입자의 침착이 관찰되었으며, MR 영상은 조직변화를 평가하는 데 유용할 것으로 생각한다.