Oyama Kazuki, Kurashina Mariko, Ichinohe Fumihito, Yamada Akira, Kitoh Yoshihiro, Hayashihara Hayato, Fujihara Shuya, Nickel Marcel D, Maruyama Katsuya, Fujinaga Yasunari
Department of Radiology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
Radiology Division, Shinshu University Hospital, Matsumoto, Nagano, Japan.
Magn Reson Med Sci. 2025 Jul 31;24(4). doi: 10.2463/mrms.mp.2023-0120. Epub 2024 May 17.
To evaluate how the relationship between respiratory interval (RI) and temporal resolution (TR) impacts image quality in free-breathing abdominal MRI (FB-aMRI) using golden-angle radial sparse parallel (GRASP).
Ten healthy volunteers (25.9 ± 2.5 years, four women) underwent 2 mins free-breathing fat-suppression T1-weighted imaging using GRASP at RIs of 3 and 5s (RI and RI, respectively) and retrospectively reconstructed at TR of 1.8, 2.9, 4.8, and 7.7s (TR, TR, TR, and TR, respectively) in each patient. The standard deviation (SD) under the diaphragm was measured using SD maps showing the discrepancy for each horizontal section at all TRs. Two radiologists evaluated image quality (visualization of the right hepatic vein at the confluence of the inferior vena cava, posterior segment branch of portal vein, pancreas, left kidney, and artifacts) at all TRs using a 5-point scale.
The SD was significantly higher at TR compared to TR (P < 0.01) and TR (P < 0.001), as well as at TR compared to TR (P < 0.01) for both RIs. The SD between TR and TR did not differ for both RIs. For all visual assessment metrics, the TR scores were significantly lower than the TR and TR scores for both RIs. The pancreas and left kidney scores at TR were significantly lower than those at TR (P < 0.05) for RI. Additionally, the left kidney score at TR was lower than that at TR (P < 0.05) for RI. All scores at TR, TR, and TR were similar for RI, while those at TR and TR were similar for RI.
Prolonging the TRs compared to RIs enhances image quality in FB-aMRI using GRASP.
评估呼吸间隔（RI）与时间分辨率（TR）之间的关系如何影响使用黄金角径向稀疏并行（GRASP）技术的自由呼吸腹部磁共振成像（FB-aMRI）的图像质量。
10名健康志愿者（25.9±2.5岁，4名女性）在呼吸间隔分别为3秒和5秒（分别为RI和RI）的情况下，使用GRASP进行2分钟的自由呼吸脂肪抑制T1加权成像，并在每位患者中分别以1.8秒、2.9秒、4.8秒和7.7秒（分别为TR、TR、TR和TR）的时间分辨率进行回顾性重建。使用标准差（SD）图测量膈肌下方的标准差，该图显示了所有时间分辨率下每个水平截面的差异。两名放射科医生使用5分制对所有时间分辨率下的图像质量（下腔静脉汇合处的右肝静脉、门静脉后段分支、胰腺、左肾的可视化以及伪影）进行评估。
对于两种呼吸间隔，与TR相比，TR时的标准差显著更高（P<0.01），与TR相比，TR时的标准差也显著更高（P<0.001）；与TR相比，TR时的标准差在两种呼吸间隔下均无差异。对于所有视觉评估指标，两种呼吸间隔下TR的评分均显著低于TR和TR的评分。对于呼吸间隔为RI的情况，TR时胰腺和左肾的评分显著低于TR时（P<0.05）。此外，对于呼吸间隔为RI的情况，TR时左肾的评分低于TR时（P<0.05）。呼吸间隔为RI时，TR、TR和TR的所有评分相似，而呼吸间隔为RI时，TR和TR的评分相似。
在使用GRASP技术的FB-aMRI中，与呼吸间隔相比延长时间分辨率可提高图像质量。
