Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
NMR Biomed. 2022 Oct;35(10):e4786. doi: 10.1002/nbm.4786. Epub 2022 Jun 27.
Tubular atrophy and fibrosis are pathological changes that determine the prognosis of kidney disease induced by acute kidney injury (AKI). We aimed to evaluate multiple magnetic resonance imaging (MRI) parameters, including pool size ratio (PSR) from quantitative magnetization transfer, relaxation rates, and measures from spin-lock imaging ( and ), for assessing the pathological changes associated with AKI-induced kidney disease. Eight-week-old male C57BL/6 J mice first underwent unilateral ischemia reperfusion injury (IRI) induced by reperfusion after 45 min of ischemia. They were imaged using a 7T MRI system 56 days after the injury. Paraffin tissue sections were stained using Masson trichrome and picrosirius red to identify histopathological changes such as tubular atrophy and fibrosis. Histology detected extensive tubular atrophy and moderate fibrosis in the cortex and outer stripe of the outer medulla (CR + OSOM) and more prominent fibrosis in the inner stripe of the outer medulla (ISOM) of IRI kidneys. In the CR + OSOM region, evident decreases in PSR, , , , and showed in IRI compared with contralateral kidneys, with PSR and exhibiting the most significant changes. In addition, the exchange parameter dropped by the largest degree among all the MRI parameters, while increased significantly. In the ISOM of IRI kidneys, PSR increased while kept decreasing. , , and all increased due to more severe fibrosis in this region. Among MRI measures, PSR and showed the highest detectability of renal changes no matter whether tubular atrophy or fibrosis dominated. and could be more specific to a single pathological event than other MRI measures because only increased and decreased consistently when either fibrosis or tubular atrophy dominated, and their correlations with fibrosis scores were higher than other MRI measures. Multiparametric MRI may enable a more comprehensive analysis of histopathological changes following AKI.
管状萎缩和纤维化是决定急性肾损伤（AKI）所致肾脏疾病预后的病理变化。我们旨在评估多种磁共振成像（MRI）参数，包括定量磁化传递的池大小比（PSR）、弛豫率以及来自自旋锁定成像（ 和 ）的测量值，以评估与 AKI 诱导的肾脏疾病相关的病理变化。8 周龄雄性 C57BL/6J 小鼠首先通过缺血 45 分钟后再灌注引起单侧缺血再灌注损伤（IRI）。在损伤后 56 天，使用 7T MRI 系统对其进行成像。使用 Masson 三色和苦味酸天狼猩红染色对石蜡组织切片进行染色，以识别管状萎缩和纤维化等组织病理学变化。组织学检测到 IRI 肾脏的皮质和外髓外带（CR+OSOM）广泛的管状萎缩和中度纤维化，以及外髓内带（ISOM）更明显的纤维化。在 CR+OSOM 区域，与对侧肾脏相比，IRI 肾脏的 PSR、 、 、 、 和 均明显降低，其中 PSR 和 变化最显著。此外，在所有 MRI 参数中，交换参数 下降幅度最大，而 显著增加。在 IRI 肾脏的 ISOM 中，PSR 增加而 持续降低。由于该区域纤维化更严重， 、 、 和 均增加。在 MRI 测量值中，无论管状萎缩还是纤维化占主导地位，PSR 和 对肾脏变化的检测能力最高。 和 可能比其他 MRI 测量值更能针对单一病理事件，因为只有在纤维化或管状萎缩占主导地位时， 才会增加而 会降低，并且它们与纤维化评分的相关性高于其他 MRI 测量值。多参数 MRI 可能使 AKI 后组织病理学变化的分析更加全面。
