Chair of Biomedical Physics, School of Natural Sciences & Department of Physics, Munich Institute of Biomedical Engineering, Technical University of Munich, München, Germany.
Institute of Diagnostic and Interventional Radiology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, München, Germany.
PLoS One. 2023 Apr 14;18(4):e0279323. doi: 10.1371/journal.pone.0279323. eCollection 2023.
The differentiation of minimal-fat-or low-fat-angiomyolipomas from other renal lesions is clinically challenging in conventional computed tomography. In this work, we have assessed the potential of grating-based x-ray phase-contrast computed tomography (GBPC-CT) for visualization and quantitative differentiation of minimal-fat angiomyolipomas (mfAMLs) and oncocytomas from renal cell carcinomas (RCCs) on ex vivo renal samples.
Laboratory GBPC-CT was performed at 40 kVp on 28 ex vivo kidney specimens including five angiomyolipomas with three minimal-fat (mfAMLs) and two high-fat (hfAMLs) subtypes as well as three oncocytomas and 20 RCCs with eight clear cell (ccRCCs), seven papillary (pRCCs) and five chromophobe RCC (chrRCC) subtypes. Quantitative values of conventional Hounsfield units (HU) and phase-contrast Hounsfield units (HUp) were determined and histogram analysis was performed on GBPC-CT and grating-based attenuation-contrast computed tomography (GBAC-CT) slices for each specimen. For comparison, the same specimens were imaged at a 3T magnetic resonance imaging (MRI) scanner.
We have successfully matched GBPC-CT images with clinical MRI and histology, as GBPC-CT presented with increased soft tissue contrast compared to absorption-based images. GBPC-CT images revealed a qualitative and quantitative difference between mfAML samples (58±4 HUp) and oncocytomas (44±10 HUp, p = 0.057) and RCCs (ccRCCs: 40±12 HUp, p = 0.012; pRCCs: 43±9 HUp, p = 0.017; chrRCCs: 40±7 HUp, p = 0.057) in contrast to corresponding laboratory attenuation-contrast CT and clinical MRI, although not all differences were statistically significant. Due to the heterogeneity and lower signal of oncocytomas, quantitative differentiation of the samples based on HUp or in combination with HUs was not possible.
GBPC-CT allows quantitative differentiation of minimal-fat angiomyolipomas from pRCCs and ccRCCs in contrast to absorption-based imaging and clinical MRI.
在常规计算机断层扫描中，从其他肾脏病变中区分最小脂肪或低脂肪血管平滑肌脂肪瘤具有临床挑战性。在这项工作中，我们评估了基于光栅的 X 射线相衬计算机断层扫描（GBPC-CT）在离体肾脏样本中可视化和定量区分最小脂肪血管平滑肌脂肪瘤（mfAML）和嗜酸细胞瘤与肾细胞癌（RCC）的潜力。
在 28 个离体肾脏标本上进行实验室 GBPC-CT，包括五个血管平滑肌脂肪瘤，其中三个为最小脂肪（mfAML），两个为高脂肪（hfAML）亚型，三个嗜酸细胞瘤和 20 个 RCC，其中 8 个为透明细胞（ccRCC），7 个为乳头状（pRCC）和 5 个嫌色细胞 RCC（chrRCC）亚型。确定了常规亨氏单位（HU）和相衬亨氏单位（HUp）的定量值，并对每个标本的 GBPC-CT 和基于光栅衰减对比的计算机断层扫描（GBAC-CT）切片进行了直方图分析。为了比较，对同一标本进行了 3T 磁共振成像（MRI）扫描。
我们成功地将 GBPC-CT 图像与临床 MRI 和组织学相匹配，因为与基于吸收的图像相比，GBPC-CT 显示出软组织对比度增加。GBPC-CT 图像显示 mfAML 样本（58±4 HUp）和嗜酸细胞瘤（44±10 HUp，p = 0.057）与 RCC（ccRCC：40±12 HUp，p = 0.012；pRCC：43±9 HUp，p = 0.017；chrRCC：40±7 HUp，p = 0.057）之间存在定性和定量差异，尽管并非所有差异均具有统计学意义。由于嗜酸细胞瘤的异质性和信号较低，因此无法根据 HUp 或与 HUs 结合对样本进行定量区分。
与基于吸收的成像和临床 MRI 相比，GBPC-CT 允许定量区分最小脂肪血管平滑肌脂肪瘤与 pRCC 和 ccRCC。
