Buntrock Clare E, Dinçer Ceren, Tuncer Onur, White Matthew, Swensen Alexis, Folkertsma Mark, Özütemiz Can
From the University of Minnesota Medical School (C.E.B.), Minneapolis, Minnesota.
Department of Radiology (C.D.), Hacettepe University, Faculty of Medicine, Ankara, Turkiye.
AJNR Am J Neuroradiol. 2025 Mar 4;46(3):627-634. doi: 10.3174/ajnr.A8513.
DSC perfusion is an advanced imaging technique routinely used at 1.5T and 3T MRI. However, its utility is not well known in 7T MRI systems. We aim to evaluate if DSC perfusion is a valid and practicable tool at 7T MRI.
A successful DSC perfusion was performed in 9 patients with an FDA-approved 7T MRI system (Siemens Terra with 1tx/32rx Nova head coil) in 2023. Half-dose contrast was administered by hand, followed by saline flush. Acquisition was initiated 45 seconds before contrast injection. Voxel size was 1.5 × 1.5 × 1.6 mm. Perfusion maps were generated by using either SyngoVia or DynaSuite software. Parameters including relative CBV (rCBV), relative CBF (rCBF), relative MTT (rMTT), and relative TTP (rTTP) were measured in 5 anatomic locations bilaterally (precentral gyrus, middle frontal gyrus, corona radiata, thalamus, occipital cortex) and enhancing lesions if present. Normalized ratios of rCBV (nrCBV), rCBF (nrCBF), rMTT (nrMTT), and rTTP (nrTTP) were calculated and compared on boxplots. Two neuroradiologists reviewed each scan visually by using a 5-point Likert scale regarding imaging quality and artifacts. Qualitative and quantitative assessments were made on DSC perfusion in cases with enhanced target lesions.
Uploading the source images to imaging software took approximately 30 minutes to a few hours. In a few circumstances, large data caused software crashes. Map generation took approximately 10-15 minutes. Susceptibility artifacts varied from mild to moderate in cerebellum, temporal lobes, brainstem, and basal ganglia and none to minimal in the frontal, occipital, and parietal gyri. Map quality was excellent to reasonably good for all cases. The nrCBV, nrCBF, nrMTT, and nrTTP resulted in similar measurements for each anatomic area. Six target lesions were assessed in 2 different patients with well to excellent visualization on fused maps. Three lesions were characterized as tumor progression (1 biopsy-confirmed, 2 unconfirmed), 1 lesion as indeterminant (regressed in follow-up), and 2 lesions as radiation necrosis (1 stable, 1 regressed on follow-up).
Despite limitations with postprocessing issues, it is possible to reliably measure nrCBV, nrCBF, nrMTT, and nrTTP values with DSC perfusion by using a clinical 7T MRI system, and qualitatively, excellent or reasonably good fusion maps can be generated with high resolution.
动态磁敏感对比增强灌注成像（DSC灌注）是一种先进的成像技术，常用于1.5T和3T磁共振成像（MRI）。然而，其在7T MRI系统中的应用尚不为人熟知。我们旨在评估DSC灌注在7T MRI中是否是一种有效且可行的工具。
2023年，使用美国食品药品监督管理局（FDA）批准的7T MRI系统（配备1发射/32接收Nova头部线圈的西门子Terra）对9例患者成功进行了DSC灌注。手动给予半剂量造影剂，随后用生理盐水冲洗。在注射造影剂前45秒开始采集。体素大小为1.5×1.5×1.6毫米。使用SyngoVia或DynaSuite软件生成灌注图。在双侧5个解剖位置（中央前回、额中回、放射冠、丘脑、枕叶皮质）测量包括相对脑血容量（rCBV）、相对脑血流量（rCBF）、相对平均通过时间（rMTT）和相对达峰时间（rTTP）等参数，若有强化病变也进行测量。计算并在箱线图上比较rCBV（nrCBV）、rCBF（nrCBF）、rMTT（nrMTT）和rTTP（nrTTP）的标准化比值。两位神经放射科医生使用5分李克特量表对每次扫描的图像质量和伪影进行视觉评估。对有强化靶病变的病例进行DSC灌注的定性和定量评估。
将源图像上传到成像软件大约需要30分钟到数小时。在少数情况下，大数据导致软件崩溃。图生成大约需要10 - 15分钟。在小脑、颞叶、脑干和基底节中，磁敏感伪影从轻度到中度不等，而在额叶、枕叶和顶叶中则无伪影或伪影极少。所有病例的图质量均为优秀至良好。每个解剖区域的nrCBV、nrCBF、nrMTT和nrTTP测量结果相似。在2例不同患者中评估了6个靶病变，融合图上显示良好至优秀。3个病变被判定为肿瘤进展（1个经活检证实，2个未证实），1个病变不确定（随访中消退），2个病变为放射性坏死（1个稳定，1个随访中消退）。
尽管在后期处理方面存在局限性，但使用临床7T MRI系统通过DSC灌注可靠测量nrCBV、nrCBF、nrMTT和nrTTP值是可行的，并且在定性方面，可以生成具有高分辨率的优秀或良好融合图。
