Department of Pediatric Radiology, University Hospital, Liebigstraße 20a, 04107, Leipzig, Germany.
Biomedical NMR, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
Pediatr Radiol. 2023 Jan;53(1):12-20. doi: 10.1007/s00247-022-05421-8. Epub 2022 Jul 15.
Real-time magnetic resonance imaging (MRI) based on a fast low-angle shot technique 2.0 (FLASH 2.0) is highly effective against artifacts caused due to the bulk and pulmonary and cardiac motions of the patient. However, to date, there are no reports on the application of this innovative technique to pediatric lung MRI.
This study aimed to identify the limits of resolution and image quality of real-time lung MRI in children and to assess the types and minimal size of lesions with these new sequences.
In this retrospective study, pathological lung findings in 87 children were classified into 6 subgroups, as detected on conventional MRI: metastases and tumors, consolidation, scars, hyperinflation, interstitial pathology and bronchiectasis. Subsequently, the findings were grouped according to size (4-6 mm, 7-9 mm and ≥ 10 mm) and evaluated for visual delineation of the findings (0 = not visible, 1 = hardly visible and 2 = well visualized).
Real-time MRI allows for diagnostic, artifact-free thorax images to be obtained, regardless of patient movements. The delineation of findings strongly correlates with the size of the pathology. Metastases, consolidation and scars were visible at 100% when larger than 9 mm. In the 7-9 mm subgroup, the visibility was 83% for metastases, 88% for consolidation and 100% for scars in T2/T1 weighting. Though often visible, smaller pathological lesions of 4-6 mm in size did not regularly meet the expected diagnostic confidence: The visibility of metastases was 18%, consolidation was 64% and scars was 71%. Diffuse interstitial lung changes and hyperinflation, known as "MR-minus pathologies," were not accessible to real-time MRI.
The method provides motion robust images of the lung and thorax. However, the lower sensitivity for small lung lesions is a major limitation for routine use of this technique. Currently, the method is adequate for diagnosing inflammatory lung diseases, atelectasis, effusions and lung scarring in children with irregular breathing patterns or bulk motion on sedation-free MRI. A medium-term goal is to improve the diagnostic accuracy of small nodules and interstitial lesions.
基于快速小角度激发技术 2.0（FLASH 2.0）的实时磁共振成像（MRI）对于减轻因患者的整体运动、肺部运动和心脏运动导致的伪影非常有效。然而，迄今为止，尚无关于该创新技术在儿科肺部 MRI 中应用的报道。
本研究旨在确定实时肺部 MRI 在儿童中的分辨率和图像质量的限制，并评估这些新序列对病变类型和最小病变大小的检测能力。
在这项回顾性研究中，将 87 名儿童的肺部病变病理结果分为以下 6 个亚组，通过常规 MRI 进行检测：转移瘤和肿瘤、实变、瘢痕、肺气肿、间质性病变和支气管扩张。然后，根据大小（4-6mm、7-9mm 和≥10mm）对这些结果进行分组，并评估这些结果的可视性（0=不可见，1=难以可见，2=可见）。
实时 MRI 可获得无伪影的、可用于诊断的胸部图像，无论患者的运动情况如何。病变的描绘与病变的大小密切相关。当病变大于 9mm 时，转移瘤、实变和瘢痕均可见，且不存在伪影。在 7-9mm 亚组中，T2/T1 加权时转移瘤的可见度为 83%，实变的可见度为 88%，瘢痕的可见度为 100%。尽管这些病变经常可见，但较小的 4-6mm 大小的病变则并不总是能满足预期的诊断信心：转移瘤的可见度为 18%，实变的可见度为 64%，瘢痕的可见度为 71%。弥漫性间质肺改变和肺气肿，即“MR 阴性病变”，无法通过实时 MRI 进行检测。
该方法可提供运动伪影较小的肺部和胸部图像。然而，对于较小的肺部病变的低敏感性是该技术常规应用的一个主要限制。目前，该方法可用于诊断儿童不规则呼吸模式或在无镇静 MRI 时因整体运动导致的呼吸暂停时的肺部炎症性疾病、肺不张、胸腔积液和肺瘢痕。中期目标是提高对小结节和间质性病变的诊断准确性。
