Poetter-Lang Sarah, Ambros Raphael, Messner Alina, Kristic Antonia, Hodge Jacqueline C, Bastati Nina, Schima Wolfgang, Chernyak Victoria, Bashir Mustafa R, Ba-Ssalamah Ahmed
Department of Biomedical Imaging and Image-Guided Therapy, Medical University, General Hospital of Vienna (AKH), Waehringer Guertel 18-20, 1090, Vienna, Austria.
Department of Diagnostic and Interventional Radiology, Clinic Donaustadt, Vienna Healthcare Group, Vienna, Austria.
Eur Radiol. 2024 Aug;34(8):5215-5227. doi: 10.1007/s00330-024-10590-1. Epub 2024 Jan 20.
Arterial-phase artifacts are gadoxetic acid (GA)-enhanced MRI's major drawback, ranging from 5 to 39%. We evaluate the effect of dilution and slow injection of GA using automated fluoroscopic triggering on liver MRI arterial-phase (AP) acquisition timing, artifact frequency, and lesion visibility.
Saline-diluted 1:1 GA was injected at 1 ml/s into 1413 patients for 3 T liver MRI. Initially, one senior abdominal radiologist, i.e., principal investigator (PI), assessed all MR exams and compared them to previous and follow-up images, as well as the radiology report on record, determining the standard of reference for lesion detection and characterization. Then, three other readers independently evaluated the AP images for artifact type (truncation (TA), transient severe motion (TSM) or mixed), artifact severity (on a 5-point scale), acquisition timing (on a 4-point scale) and visibility (on a 5-point scale) of hypervascular lesions ≥ 5 mm, selected by the PI. Artifact score ≥ 4 and artifact score ≤ 3 were considered significant and non-significant artifacts, respectively.
Of the 1413 exams, diagnostic-quality arterial-phase images included 1100 (77.8%) without artifacts, 220 (15.6%) with minimal, and 77 (5.4%) with moderate artifacts. Only 16 exams (1.1%) had significant artifacts, 13 (0.9%) with severe artifacts (score 4), and three (0.2%) non-diagnostic artifacts (score 5). AP acquisition timing was optimal in 1369 (96.8%) exams. Of the 449 AP hypervascular lesions, 432 (96.2%) were detected.
Combined dilution and slow injection of GA with MR results in well-timed arterial-phase images in 96.8% and a reduction of exams with significant artifacts to 1.1%.
Hypervascular lesions, in particular HCC detection, hinge on arterial-phase hyperenhancement, making well-timed, artifact-free arterial-phase images a prerequisite for accurate diagnosis. Saline dilution 1:1, slow injection (1 ml/s), and automated bolus triggering reduce artifacts and optimize acquisition timing.
• There was substantial agreement among the three readers regarding the presence and type of arterial-phase (AP) artifacts, acquisition timing, and lesion visibility. • Impaired AP hypervascular lesion visibility occurred in 17 (3.8%) cases; in eight lesions due to mistiming and in nine lesions due to significant artifacts. • When AP timing was suboptimal, it was too late in 40 exams (3%) and too early in 4 exams (0.2%) of exams.
动脉期伪影是钆塞酸二钠（GA）增强MRI的主要缺点，发生率为5%至39%。我们评估了使用自动透视触发技术对GA进行稀释和缓慢注射，对肝脏MRI动脉期（AP）采集时间、伪影频率和病变可视性的影响。
将1:1生理盐水稀释的GA以1ml/s的速度注入1413例患者体内，用于3T肝脏MRI检查。最初，由一位资深腹部放射科医生，即主要研究者（PI）评估所有MR检查，并将其与之前和后续的图像以及记录在案的放射学报告进行比较，确定病变检测和特征描述的参考标准。然后，另外三位阅片者独立评估AP图像，以确定伪影类型（截断伪影（TA）、短暂严重运动伪影（TSM）或混合伪影）、伪影严重程度（采用5分制）、采集时间（采用4分制）以及PI选择的≥5mm的富血管病变的可视性（采用5分制）。伪影评分≥4分和伪影评分≤3分分别被视为显著伪影和非显著伪影。
在1413例检查中，诊断质量的动脉期图像包括1100例（77.8%）无伪影、220例（15.6%）有轻微伪影和77例（5.4%）有中度伪影。只有16例检查（1.1%）有显著伪影，13例（0.9%）有严重伪影（评分4分），3例（0.2%）有非诊断性伪影（评分5分）。1369例（96.8%）检查的AP采集时间最佳。在449个AP富血管病变中，检测到432个（96.2%）。
GA与MR联合进行稀释和缓慢注射，可使96.8%的动脉期图像采集时间合适，并将有显著伪影的检查减少到1.1%。
富血管病变，尤其是肝细胞癌的检测，依赖于动脉期的高增强，因此，适时、无伪影的动脉期图像是准确诊断的前提。1:1生理盐水稀释、缓慢注射（1ml/s）和自动团注触发可减少伪影并优化采集时间。
• 三位阅片者在动脉期（AP）伪影的存在和类型、采集时间以及病变可视性方面存在高度一致性。• 17例（3.8%）病例中AP富血管病变可视性受损；8例病变是由于时间错误，9例病变是由于显著伪影。• 当AP时间不理想时，40例检查（3%）中时间过晚，4例检查（0.2%）中时间过早。
