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      • 두통 환자에서 뇌자기공명영상의 유용성

        전인석,김철환,이언숙,서홍관,이기재 인제대학교 1999 仁濟醫學 Vol.20 No.1S

        연구배경; 두통은 가장 일반적인 증상이지만 많은 경우에서 사람을 무능력 하게 한다. 무엇보다 두통이 심하거나 오래 계속될 경우 뇌종양에 대한 공포가 있다. 임상 의사들도 최근 의료 사고 및 의료 분쟁의 증가로 인해 방어 진료를 하고 있다. 이런 이유에서 최근 고가 장비인 뇌자기공명영상을 두통 환자에서 시행하는 일이 많아지고 있다. 이 연구는 두통을 호소하는 환자에게서 신경학적 징후가 없을때, 뇌자기공명영상이 유용성이 있는 지를 알아보기 위한 연구이다. 방법; 1993년 1월 1일부터 1997년 3월 31일까지 서울백병원과 상계백병원 신경과, 신경외과, 소아과, 가정의학과 외래에 두통을 주소로 내원하여, 뇌자기공명영상을 시행한 환자 중에서, 임상 병록지를 검토하여 외상. 국소적 신경 증상 및 징후를 나타내거나 의식 소실이 있었던 경우, 과거력상 뇌혈관 사고의 병력이 있었던 경우를 제외시킨 123명을 대상으로 성별, 연령, 병력, 동반 증상, 두통의 이환 기간, 지자기 공명영상 소견을 조사하였다. 결과; 연구 대상은 남자 40명(32.5%), 여자 83명(675%)으로 총 123명이었다 환자의 연령은 7세에서 70세였으며, 평균 연령은 41.8세였다. 40대가 36명(29.3%), 30대가 29명(23.6%)이었다. 환자들의 병력은 고혈압이 10예(8.1%)로 가장 많았고 특별한 질병이 기재되어 있지 않은 경우가 107예(87.1%)였다. 두통과 연관된 뇌자기공명영상 이상 소견 14예 중에 동반질환이 있었던 예는 모두 5예(4.0%)였으며 상관 관계에는 유의성이 있었다(P<0.05). 두통과 동반한 증상은 오심 25예(20.3%), 어지러움 11예(8.9%) 구토 9예(7.3%) 안구통 7예(5.7%)였다. 두통과 동반한 증상과 뇌자기공명영상 이상 소견과의 상관 관계에는 유의성이 없었다(P>0.05). 두통의 이환 기간은 12개월에서 60개월이 37예(30.0%)로 가장 많았고, 1개월에서 11개월이 28예(22.8%), 60개월 이상이 27예(22.0%), 1개월 미만이 22예(17.9%)의 순이었다. 두통의 평균 이환 기간은 4년 2개월이었다. 두통 이환 기간과 뇌자기공명영상 이상 소견과의 상관관계에는 유의성이 없었다(P>0.05). 뇌자기공명영상 소견은 총 123예 중 정상 소견이 96예(78.0%), 이상 소견이 27예(22.0%)였으며, 이상 소견 중에 두통과 관련이 있는 소견은 14예(11.4%)로, 열공경색증(lacunar infarction) 8예(6.5%), 뇌허혈(cerebral ischemia) 3예(2.4%), 뇌수막종(meningioma) 2예(1.6%), 거미막낭종(arachnoid cyst) 1예(0.8%), 투명중격낭(cyst of septum pellucidum) 1예(0.8%)이며, 두통과 관련이 없는 이상 소견은, 뇌위축(cerebral atrophy) 3예(2.4%), 송과체낭종(pineal cyst) 1예(0.8%), mega cisterna magna 1예 (0.8%)였다. 결론; 본 연구에서 두통과 임상적으로 의미있는 뇌자기공명영상 소견은 두통 환자 123명 중에 14예(11.4%)였다. 따라서 두통 환자에서 적극적인 병력 청취와 이학적 검사를 실시하되, 충분한 기간 적절한 치료에도 반응이 없는 두통 환자는 뇌자기공명영상 촬영 등의 검사를 고려해야겠다. Background: Headache is a common symptom. but for many it can be a debilitating problem. The patients with headache tend to worry excessively about the possibility of cerebral tumor as the cause when it is severe and longstanding. Clinicians have protective attitude towards the management of headache because medical law suits have increased recently. For this reason, expensive Brain Magnetic Resonance Imaging has been used more often in the evaluation of headache patients recently. So we studied the usefulness of Brain Magnetic Resonance Imaging in the management of patients with headache who were neurologically normal. Methods: From January 1, 1993 to March 31, 1997, 123 patients with headache who had visited the department of neurology, neurosurgery, pediatric, and family medicine in Seoul and Sanggye Paik Hospital and had undergone Brain Magnetic Resonance Imagings. We reviewed the charts and selected the patients who had no prior histories of trauma, focal neurologic symptoms and signs, loss of consciousness, and cerebrovascular accidents. We checked their age, sex, past medical history, duration of headache, and Brain Magnetic Resonance Imaging findings. Results: There were total of 123 patients with headache. Subjects were 40 males(32.5%) and 83 females(67.5%). Male-to-female ratio was 1:2.1. The age ranged from 7 to 80 years with an average of 41.8 years. Thirty six patients(29.3%) were in their forties, 29(23.6%) in their thirties. Ten patients(8.1%) had histories of hypertension. Five of 10 patients(4.1%) with pastmedical disease were related with abnormal Brain Magnetic Resonance Imagings(P<0.05). The symptoms accompanying headache in order of frequency were nausea 25(20.3%), dizziness 11(8.9%), vomiting 9(7.3%), and eye pain 7(5.7%), Associated symptoms with headache did not correlate with abnormal Brain Magnetic Resonance Imagings(P>0.05) The duration of headache was 12 to 60 months in 37 patients(30.0%) , 1 to 11 months in 28(22.8%), above 60 months in 27(22.0%), and below 1 month in 22(17.9%), with an average duration of 4 years and 2 months. The duration of headache did not correlate with abnormal Brain Magnetic Resonance Imagings(P>0.05). Brain Magnetic Resonance Imaging findings were normal in 96 patients(78.0%). abnormal in 27(22.0%) headache relaxed findings in 14(11.4%) ; lacunar infarction in 8(6.5%), cerebral ischemia in 3(2.4), meningioma in 2(1.6%), arachnoid cyst in 1 (0.8%), and cyst of septum pellucidum in 1 (0.8%). Conclusions: There were clinically meaningful findings in Brain Magnetic Resonance Imaging in 14(11.4%) among 123 patients with headache. Primary care physician should take history and perform physical examination intensively, but consider Brain Magnetic Resonance Imaging if headache does not resolve by proper management.

      • SCOPUSKCI등재

        자가공명영상(Magnetic Resonance Imaging)의 기본원리

        조봉혜,Cho Bong-Hae 대한영상치의학회 1999 Imaging Science in Dentistry Vol.29 No.1

        Magnetic resonance imaging with its superior soft tissue contrast resolution and absence of beam hardening artifacts, combined with its ability to perform multiplanar imaging, is now effective tool in diagnostic imagings. Magnetic resonance is primarily a phenomenon that involves atomic nuclei. It provides totally new clinical informations with no known hazards through the use of very weak interactions with endogenous stable magnetic atomic nuclei. This article briefly summarizes the basic mechanism of generation and detection of the signals and general sorts of tissue properties which can influence the signals and thereby give rise to tissue contrast. It also describes how the machine-operating parameters can be used to manipulate the tissue contrast observed in the image.

      • KCI등재

        개의 경막외 혈종의 자기공명영상학적 진단

        최치봉,김휘율,김수관,배춘식,Choi, Chi-Bong,Kim, Hwi-Yool,Kim, Su-Gwan,Bae, Chun-Sik 대한악안면성형재건외과학회 2005 Maxillofacial Plastic Reconstructive Surgery Vol.27 No.5

        A 3-year-old female, 5kg, Shih-tzu developed an acute onset of depression, disorientation, hypersalivation, nystagmus after falling down 2 meter height place. In plain skull radiography, there was fracture line in the frontal and parietal bones and next day magnetic resonance imaging examination was performed. Magnetic resonance imaging of the brain was performed with 3.0 Tesla unit. Under general anesthesia, the dog was placed in prone with its head positioned in a birdcage coil. Transverse, sagittal and coronal fast spin echo images of the brain were obtained with the following pulse sequences: T1 weighted images (TR = 560 ms and TE = 18.6 ms) and T2 weighted images (TR = 3500 ms and TE = 80 ms). Magnetic resonance imaging showed epidural hematoma in the left frontal area resulting in compression of the adjacent brain parenchyma. Left lateral ventricle was compressed secondarily and the longitudinal fissure shifted to the right, representing mass effect. The lesion was iso-to slightly hyperintense on T1 weighted image and iso-slightly hypointense signal on T2 weighted image. At necropsy, there was a skull fracture and epidural hematoma in the left frontal area. Magnetic resonance imaging of epidural hematoma is reviewed.

      • KCI등재

        Optimization of the Flip Angle and Scan Timing in Hepatobiliary Phase Imaging Using T1-Weighted, CAIPIRINHA GRE Imaging

        Jeongjae Kim,Bong Soo Kim,Jeong Sub Lee,Seung Tae Woo,Guk Myung Choi,Seung Hyoung Kim,Ho Kyu Lee,Mu Sook Lee,Kyung Ryeol Lee,Joon Hyuk Park 대한자기공명의과학회 2018 Investigative Magnetic Resonance Imaging Vol.22 No.1

        Purpose: This study was designed to optimize the flip angle (FA) and scan timing of the hepatobiliary phase (HBP) using the 3D T1-weighted, gradient-echo (GRE) imaging with controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) technique on gadoxetic acid-enhanced 3T liver MR imaging. Materials and Methods: Sixty-two patients who underwent gadoxetic acidenhanced 3T liver MR imaging were included in this study. Four 3D T1-weighted GRE imaging studies using the CAIPIRINHA technique and FAs of 9° and 13° were acquired during HBP at 15 and 20 min after intravenous injection of gadoxetic acid. Two abdominal radiologists, who were blinded to the FA and the timing of image acquisition, assessed the sharpness of liver edge, hepatic vessel clarity, lesion conspicuity, artifact severity, and overall image quality using a five-point scale. Quantitative analysis was performed by another radiologist to estimate the relative liver enhancement (RLE) and the signal-to-noise ratio (SNR). Statistical analyses were performed using the Wilcoxon signed rank test and one-way analysis of variance. Results: The scores of the HBP with an FA of 13° during the same delayed time were significantly higher than those of the HBP with an FA of 9° in all the assessment items (P < 0.01). In terms of the delay time, images at the same FA obtained with a 20-min-HBP showed better quality than those obtained with a 15-min-HBP. There was no significant difference in qualitative scores between the 20-min-HBP and the 15-min-HBP images in the non-liver cirrhosis (LC) group except for the hepatic vessel clarity score with 9° FA. In the quantitative analysis, a statistically significant difference was found in the degree of RLE in the four HBP images (P = 0.012). However, in the subgroup analysis, no significant difference in RLE was found in the four HBP images in either the LC or the non-LC groups. The SNR did not differ significantly in the four HBP images. In the subgroup analysis, 20-min-HBP imaging with a 13° FA showed the highest SNR value in the LC-group, whereas 15-min-HBP imaging with a 13° FA showed the best value of SNR in the non-LC group. Conclusion: The use of a moderately high FA improves the image quality and lesion conspicuity on 3D, T1-weighted GRE imaging using the CAIPIRINHA technique on gadoxetic acid, 3T liver MR imaging. In patients with normal liver function, the 15-min-HBP with a 13° FA represents a feasible option without a significant decrease in image quality.

      • Aptamer-modified magnetic nanoprobe for molecular MR imaging of VEGFR2 on angiogenic vasculature

        Kim, Bongjune,Yang, Jaemoon,Hwang, Myeonghwan,Choi, Jihye,Kim, Hyun-Ouk,Jang, Eunji,Lee, Jung Hwan,Ryu, Sung-Ho,Suh, Jin-Suck,Huh, Yong-Min,Haam, Seungjoo Springer 2013 Nanoscale research letters Vol.8 No.1

        <P>Nucleic acid-based aptamers have been developed for the specific delivery of diagnostic nanoprobes. Here, we introduce a new class of smart imaging nanoprobe, which is based on hybridization of a magnetic nanocrystal with a specific aptamer for specific detection of the angiogenic vasculature of glioblastoma via magnetic resonance (MR) imaging. The magnetic nanocrystal imaging core was synthesized using the thermal decomposition method and enveloped by carboxyl polysorbate 80 for water solubilization and conjugation of the targeting moiety. Subsequently, the surface of the carboxylated magnetic nanocrystal was modified with amine-functionalized aptamers that specifically bind to the vascular growth factor receptor 2 (VEGFR2) that is overexpressed on angiogenic vessels. To assess the targeted imaging potential of the aptamer-conjugated magnetic nanocrystal for VEGFR2 markers, the magnetic properties and MR imaging sensitivity were investigated using the orthotopic glioblastoma mouse model. In <I>in vivo</I> tests, the aptamer-conjugated magnetic nanocrystal effectively targeted VEGFR2 and demonstrated excellent MR imaging sensitivity with no cytotoxicity.</P>

      • KCI등재

        A magnetic resonance imaging study on changes in rat mandibular bone marrow and pulp tissue after high-dose irradiation

        이완,이병도,이강규,고광준 대한영상치의학회 2014 Imaging Science in Dentistry Vol.44 No.1

        Purpose: This study was designed to evaluate whether magnetic resonance imaging (MRI) is appropriate for detecting early changes in the mandibular bone marrow and pulp tissue of rats after high-dose irradiation. Materials and Methods: The right mandibles of Sprague-Dawley rats were irradiated with 10 Gy (Group 1, n=5) and 20 Gy (Group 2, n=5). Five non-irradiated animals were used as controls. The MR images of rat mandibles were obtained before irradiation and once a week until week 4 after irradiation. From the MR images, the signal intensity (SI) of the mandibular bone marrow and pulp tissue of the incisor was interpreted. The MR images were compared with the histopathologic findings. Results: The SI of the mandibular bone marrow had decreased on T2-weighted MR images. There was little difference between Groups 1 and 2. The SI of the irradiated groups appeared to be lower than that of the control group. The histopathologic findings showed that the trabecular bone in the irradiated group had increased. The SI of the irradiated pulp tissue had decreased on T2-weighted MR images. However, the SI of the MR images in Group 2 was high in the atrophic pulp of the incisor apex at week 2 after irradiation. Conclusion: These patterns seen on MRI in rat bone marrow and pulp tissue were consistent with histopathologic findings. They may be useful to assess radiogenic sclerotic changes in rat mandibular bone marrow. Purpose: This study was designed to evaluate whether magnetic resonance imaging (MRI) is appropriate for detecting early changes in the mandibular bone marrow and pulp tissue of rats after high-dose irradiation. Materials and Methods: The right mandibles of Sprague-Dawley rats were irradiated with 10 Gy (Group 1, n=5) and 20 Gy (Group 2, n=5). Five non-irradiated animals were used as controls. The MR images of rat mandibles were obtained before irradiation and once a week until week 4 after irradiation. From the MR images, the signal intensity (SI) of the mandibular bone marrow and pulp tissue of the incisor was interpreted. The MR images were compared with the histopathologic findings. Results: The SI of the mandibular bone marrow had decreased on T2-weighted MR images. There was little difference between Groups 1 and 2. The SI of the irradiated groups appeared to be lower than that of the control group. The histopathologic findings showed that the trabecular bone in the irradiated group had increased. The SI of the irradiated pulp tissue had decreased on T2-weighted MR images. However, the SI of the MR images in Group 2 was high in the atrophic pulp of the incisor apex at week 2 after irradiation. Conclusion: These patterns seen on MRI in rat bone marrow and pulp tissue were consistent with histopathologic findings. They may be useful to assess radiogenic sclerotic changes in rat mandibular bone marrow.

      • KCI등재

        직결장암 조직의 자기공명영상과 초음파 소견에 대한 비교 연구

        이황규,지금난,홍수진,고재향 대한자기공명의과학회 2013 Investigative Magnetic Resonance Imaging Vol.17 No.2

        Purpose : To evaluate and compare the accuracy of magnetic resonance imaging (MRI) and ultrasound (US) for detection and estimation of invasion depth of colorectal carcinoma (CRC) by correlation with histopathologic findings in vitro, and to find out the best MR pulse sequence for accurate delineation of tumor from surrounding normal tissue. Materials and Methods: Resected specimens of CRC from 45 patients were examined about tumor detectability and invasion depth of US using high frequency (5-17 MHz) linear transducer in a tube filled with normal saline and MRI in a 8-channel quadrate head coil. The institutional review board approved this study and informed consent was waived. MRI with seven pulse sequences of in- and out-of-phases gradient echo T1 weighted images, fast spin echo T2 weighted image and its fat suppression image, fast imaging employing steady-state acquisition (FIESTA) and its fat suppression image, and diffusion weighted image (DWI) were performed. In each case, both imaging findings of MRI and US were evaluated independently for detection and estimation of invasion depth of tumor by consensus of two radiologists and were compared about diagnostic accuracy according to the histopathologic findings as reference standard. Seven MR pulse sequences were evaluated on the point of accurate delineation of tumor from surrounding normal tissue in each specimen. Results: In specimens of CRC, both imaging modalities of MRI (91.1%) and US (86.7%) showed relatively high diagnostic accuracy to detect tumor and evaluate invasion depth of tumor. In early CRC, diagnostic accuracy of US was 87.5% and that of MRI was 75.0%. There was no statistically significant difference between two imaging modalities (p > 0.05). The best pulse sequence among seven MR sequences for accurate delineation of tumor from surrounding normal tissue in each specimen of CRC was fast spin echo T2 weighted image. Conclusion: MRI and US show relatively high diagnostic accuracy to detect tumor and evaluate invasion depth of resected specimen of CRC. The most excellent pulse sequence of MRI for accurate delineation of tumor from surrounding normal tissue in CRC is fast spin echo T2 weighted image. 목적 : 직결장암 조직의 자기공명영상과 고주파 초음파검사를 시행한 후 종양의 탐지와 침윤 깊이에 대해 각각의 영상 소견과병리 소견을 비교하여 진단적 정확도를 두 영상 기기 간 비교하고, 자기공명영상의 경우 종양의 침윤 깊이를 주변 정상 조직과 가장 명확히 보여주는 펄스 연쇄 (pulse sequence)에 대해 알아보았다. 대상 및 방법 : 직결장암으로 절제술을 시행한 45명의 환자에서 얻은 45예의 제거된 종양 조직을 수조에 넣고 생리 식염수에담가서 고주파수 (5-17 MHz)의 선형 탐촉자를 이용하여 초음파영상을 얻었으며 8-channel 두경부 코일에 넣어 자기공명영상을 얻었다. 이 연구에 대하여 기관감사위원회의 공지에 입각한 동의는 면제되었다. 자기공명영상은 정- 및 탈위상 경사에코 T1 강조영상, 급속스핀에코 T2 강조영상 및 이의 지방억제 영상, fast imaging employing steady-state acquisition (FIESTA)와 이의 지방억제영상, 확산강조영상 등 일곱 가지 펄스 연쇄를 시행하였다. 각 조직의 자기공명영상과 초음파영상 소견을 각각 독립적으로 종양의 탐지와 침윤 깊이에 대하여 두 명의 영상의학과 의사가 합의 하에 평가하였고각각의 영상 소견을 병리 조직 소견과 비교하여 두 영상 기기 간 진단적 정확도를 비교하였다. 자기공명영상의 일곱 가지 펄스 연쇄 중에 종양의 침윤 깊이를 주변 정상 조직과 구분하여 명확히 보여주는 펄스 연쇄에 대해 알아보았다. 결과 : 직결장암 조직의 종양 탐지와 침윤 깊이를 평가하는데 있어 자기공명영상과 초음파의 진단적 정확도는 각각 91.1%와86.7%로 높게 나타났다. 조기 직결장암의 경우 초음파 검사의 정확도는 87.5%, 자기공명영상 검사의 정확도는 75.0%로나왔다. 두 영상 기기 간에 통계적으로 유의한 차이는 없었다 (p > 0.05). MR의 펄스 연쇄 중에 종양의 침윤 깊이를 주변 정상 조직과 구분하여 명확하게 보여주는 영상은 직결장암 및 조기 직결장암 모두 급속 스핀에코 T2 강조영상이었다. 결론 : 자기공명영상과 초음파 검사는 직결장암 조직의 종양 탐지와 침윤 깊이를 평가하는데 높은 진단적 정확도를 가지고 있으며, 자기공명영상의 급속스핀에코 T2 강조영상이 직결장암 조직의 종양 침윤 깊이를 평가하는데 가장 우수하였다.

      • SCOPUSKCI등재

        Computed tomography and magnetic resonance imaging characteristics of giant cell tumors in the temporomandibular joint complex

        Choi, Yoon Joo,Lee, Chena,Jeon, Kug Jin,Han, Sang-Sun Korean Academy of Oral and Maxillofacial Radiology 2021 Imaging Science in Dentistry Vol.51 No.2

        Purpose: This study aimed to investigate the computed tomography and magnetic resonance imaging features of giant cell tumors in the temporomandibular joint region to facilitate accurate diagnoses. Materials and Methods: From October 2007 to June 2020, 6 patients (2 men and 4 women) at Yonsei University Dental Hospital had histopathologically proven giant cell tumors in the temporomandibular joint. Their computed tomography and magnetic resonance imaging findings were reviewed retrospectively, and the cases were classified into 3 types based on the tumor center and growth pattern observed on the radiologic findings. Results: The age of the 6 patients ranged from 25 to 53 years. Trismus was found in 5 of the 6 cases. One case recurred. The mean size of the tumors, defined based on their greatest diameter, was 32 mm (range, 15-41 mm). The characteristic features of all cases were a heterogeneously-enhancing tumorous mass with a lobulated margin on computed tomographic images and internal multiplicity of signal intensity on T2-weighted magnetic resonance images. According to the site of origin, 3 tumors were bone-centered, 2 were soft tissue-centered, and 1 was peri-articular. Conclusion: Computed tomography and magnetic resonance imaging yielded a tripartite classification of giant cell tumors of the temporomandibular joint according to their location on imaging. This study could help clinicians in the differential diagnosis of giant cell tumors and assist in proper treatment planning for tumorous diseases of the temporomandibular joint.

      • KCI등재후보

        복부질환 고자장 자기공명영상

        나성은 대한의사협회 2010 대한의사협회지 Vol.53 No.12

        Due to the development of dedicated receiver coils for 3 tesla (T) magnetic resonance (MR)imaging and increased gradient performance, 3T MR imaging of the abdomen is rapidly becoming a part of routine clinical practice. The most important advantage of 3T MR imaging is a higher signal-to-noise ratio and contrast-to-noise ratio compared with 1.5T systems, which can be used to improve spatial resolution and shorten image acquisition time. In the abdomen, the improved image quality of non-enhanced and enhanced solid organ imaging, MR angiography,MR cholangiopancreatography, and MR spectroscopy can be obtained at 3T due to the increased signal-to-noise ratio and contrast-to-noise ratio. However, 3T abdominal MR imaging also presents several technical challenges, such as increased energy deposition within the patient's body, standing wave artifacts, and increased susceptibility artifacts. Therefore, abdominal MR imaging at 3T requires adjustments in the sequence parameters of pulse sequences designed for 1.5T to optimize image quality. At present, 3T abdominal MR imaging is feasible with high image quality in an acceptable scan time, but 3T imaging is not significantly superior to 1.5T imaging in terms of cost-effectiveness. Future improvements in coil technology and new sequences suitable for 3T may enable wider clinical use of 3T for abdominal MR imaging.

      • KCI등재후보

        Optimization of the Flip Angle and Scan Timing in Hepatobiliary Phase Imaging Using T1-Weighted, CAIPIRINHA GRE Imaging

        Kim, Jeongjae,Kim, Bong Soo,Lee, Jeong Sub,Woo, Seung Tae,Choi, Guk Myung,Kim, Seung Hyoung,Lee, Ho Kyu,Lee, Mu Sook,Lee, Kyung Ryeol,Park, Joon Hyuk Korean Society of Magnetic Resonance in Medicine 2018 Investigative Magnetic Resonance Imaging Vol.22 No.1

        Purpose: This study was designed to optimize the flip angle (FA) and scan timing of the hepatobiliary phase (HBP) using the 3D T1-weighted, gradient-echo (GRE) imaging with controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) technique on gadoxetic acid-enhanced 3T liver MR imaging. Materials and Methods: Sixty-two patients who underwent gadoxetic acid-enhanced 3T liver MR imaging were included in this study. Four 3D T1-weighted GRE imaging studies using the CAIPIRINHA technique and FAs of $9^{\circ}$ and $13^{\circ}$ were acquired during HBP at 15 and 20 min after intravenous injection of gadoxetic acid. Two abdominal radiologists, who were blinded to the FA and the timing of image acquisition, assessed the sharpness of liver edge, hepatic vessel clarity, lesion conspicuity, artifact severity, and overall image quality using a five-point scale. Quantitative analysis was performed by another radiologist to estimate the relative liver enhancement (RLE) and the signal-to-noise ratio (SNR). Statistical analyses were performed using the Wilcoxon signed rank test and one-way analysis of variance. Results: The scores of the HBP with an FA of $13^{\circ}$ during the same delayed time were significantly higher than those of the HBP with an FA of $9^{\circ}$ in all the assessment items (P < 0.01). In terms of the delay time, images at the same FA obtained with a 20-min-HBP showed better quality than those obtained with a 15-min-HBP. There was no significant difference in qualitative scores between the 20-min-HBP and the 15-min-HBP images in the non-liver cirrhosis (LC) group except for the hepatic vessel clarity score with $9^{\circ}$ FA. In the quantitative analysis, a statistically significant difference was found in the degree of RLE in the four HBP images (P = 0.012). However, in the subgroup analysis, no significant difference in RLE was found in the four HBP images in either the LC or the non-LC groups. The SNR did not differ significantly in the four HBP images. In the subgroup analysis, 20-min-HBP imaging with a $13^{\circ}$ FA showed the highest SNR value in the LC-group, whereas 15-min-HBP imaging with a $13^{\circ}$ FA showed the best value of SNR in the non-LC group. Conclusion: The use of a moderately high FA improves the image quality and lesion conspicuity on 3D, T1-weighted GRE imaging using the CAIPIRINHA technique on gadoxetic acid, 3T liver MR imaging. In patients with normal liver function, the 15-min-HBP with a $13^{\circ}$ FA represents a feasible option without a significant decrease in image quality.

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