Li Yi, Lee Marsha M, Worters Pauline W, MacKenzie John D, Laszik Zoltan, Courtier Jesse L
1 Department of Radiology and Biomedical Imaging, University of California, San Francisco, 505 Parnassus Ave, M-391, San Francisco, CA 94143-0628.
2 Department of Pediatric Nephrology, UCSF Benioff Children's Hospital, San Francisco, CA.
AJR Am J Roentgenol. 2017 Jun;208(6):1358-1364. doi: 10.2214/AJR.16.17418. Epub 2017 Apr 5.
Fractional anisotropy (FA) is a measure of molecular motion obtained from diffusion tensor imaging (DTI). The objective of this study was to assess the use of FA as a noninvasive correlate of renal allograft histopathology.
Sixteen pediatric renal allograft recipients were imaged using DTI in a prospective study, between October 2014 and January 2016, before a same-day renal allograft biopsy. The Kendall tau correlation coefficient was used to assess the relationship between cortical and medullary FA values and several clinically important Banff renal allograft histopathology scores. The Mann-Whitney U test was also used to compare cortical and medullary FA values in the region of biopsy in patients whose biopsy results did and in those whose biopsy results did not change clinical management.
Medullary FA values had direct inverse correlation with several histopathology scores: tubulitis (designated "t" score in Banff pathologic classification, p < 0.04), interstitial inflammation (i score, p < 0.005), tubular atrophy (ct score, p < 0.002), and interstitial fibrosis (ci score, p < 0.007). Cortical FA values inversely correlated with peritubular capillaritis (ptc score, p < 0.02). Neither medullary nor cortical FA values correlated with glomerulitis (g score). At a b value of 800 s/mm, medullary FA values of pediatric renal allograft recipients whose renal biopsies prompted a change in clinical management (mean ± SD at a b value of 800 s/mm = 0.262 ± 0.07; n = 9) were statistically different compared with the group whose biopsy results did not change clinical management (mean ± SD at a b value of 800 s/mm = 0.333 ± 0.06; n = 7) (p < 0.006).
FA is a noninvasive correlate of several important renal allograft histopathology scores and a potential noninvasive method of assessing renal allograft health in pediatric allograft recipients.
分数各向异性（FA）是一种通过扩散张量成像（DTI）获得的分子运动测量指标。本研究的目的是评估FA作为肾移植组织病理学非侵入性关联指标的应用。
在2014年10月至2016年1月的一项前瞻性研究中，对16名小儿肾移植受者在同日进行肾移植活检前使用DTI进行成像。采用肯德尔tau相关系数评估皮质和髓质FA值与几个临床上重要的班夫肾移植组织病理学评分之间的关系。还使用曼-惠特尼U检验比较活检结果改变临床管理的患者与活检结果未改变临床管理的患者在活检区域的皮质和髓质FA值。
髓质FA值与几个组织病理学评分呈直接负相关：肾小管炎（班夫病理分类中的“t”评分，p < 0.04）、间质炎症（i评分，p < 0.005）、肾小管萎缩（ct评分，p < 0.002）和间质纤维化（ci评分，p < 0.007）。皮质FA值与肾小管周围毛细血管炎（ptc评分，p < 0.02）呈负相关。髓质和皮质FA值均与肾小球炎（g评分）无关。在b值为800 s/mm时，肾活检提示临床管理改变的小儿肾移植受者的髓质FA值（b值为800 s/mm时的平均值±标准差 = 0.262 ± 0.07；n = 9）与活检结果未改变临床管理的组（b值为800 s/mm时的平均值±标准差 = 0.333 ± 0.06；n = 7）相比有统计学差异（p < 0.006）。
FA是几个重要的肾移植组织病理学评分的非侵入性关联指标，也是评估小儿肾移植受者肾移植健康状况的一种潜在非侵入性方法。
