Syversveen Trygve, Brabrand Knut, Midtvedt Karsten, Strøm Erik H, Hartmann Anders, Berstad Audun Elnaes
Department of Radiology, Oslo University Hospital, Rikshospitalet, Norway.
Acta Radiol. 2011 Oct 1;52(8):920-6. doi: 10.1258/ar.2011.110215. Epub 2011 Aug 26.
Chronic allograft nephropathy (CAN) characterized by interstitial fibrosis and tubular atrophy is a major cause of renal transplant failure. The diagnosis can currently only be verified by a graft biopsy.
To evaluate whether non-invasive dynamic color Doppler sonographic parenchymal perfusion measurements are different in grafts with various degrees of biopsy proven renal transplant fibrosis.
Forty-nine adult patients were prospectively included. Four patients were excluded. Color Doppler videos from the renal cortex were recorded. Perfusion in the renal cortex was evaluated using a software package which calculates color pixel area and flow velocity, encoded by each pixel inside a region of interest of a video sequence. The software calculates parameters that describe tissue perfusion numerically. Two of these, the perfusion intensity and tissue pulsatility index, were compared to grade of interstitial fibrosis (0-3) in biopsies. Observer agreement was evaluated in a subset of 12 patients.
Of the 45 patients analyzed, 18 patients had grade 0, 18 had grade 1, seven had grade 2 and two had grade 3 fibrosis. The mean perfusion intensity of grade 0 was significantly higher than that of grade 2 and 3 fibrosis in the proximal cortical layer (1.65 m/s vs. 0.84 m/s, P = 0.008). No significant difference was found between grade 0 and grade 1 fibrosis. Perfusion intensity was correlated to estimated glomerular filtration rate (Pearson r 0.51, P = 0.001, R(2) = 0.26 and 0.46, P = 0.001, R(2) = 0.22 in the distal and proximal cortex, respectively). Inter-observer agreement of the perfusion intensity, expressed as intraclass correlation coefficient was 0.69 in the proximal part of the cortex. Intra-observer agreement was 0.85 for observer 1 and 0.82 for observer 2.
Perfusion intensity assessed by dynamic color Doppler measurements is significantly reduced in allografts with grade 2 and 3 fibrosis compared to allografts without fibrosis. Further studies involving longitudinal assessment of allografts undergoing protocol biopsies would be of interest.
以间质纤维化和肾小管萎缩为特征的慢性移植肾肾病（CAN）是肾移植失败的主要原因。目前，该诊断只能通过移植肾活检来证实。
评估在经活检证实有不同程度肾移植纤维化的移植肾中，非侵入性动态彩色多普勒实质灌注测量是否存在差异。
前瞻性纳入49例成年患者。排除4例患者。记录肾皮质的彩色多普勒视频。使用一个软件包评估肾皮质的灌注，该软件包可计算彩色像素面积和流速，这些由视频序列感兴趣区域内的每个像素编码。该软件计算以数字形式描述组织灌注的参数。将其中两个参数，即灌注强度和组织搏动指数，与活检中的间质纤维化分级（0 - 3级）进行比较。在12例患者的子集中评估观察者间的一致性。
在分析的45例患者中，18例患者为0级纤维化，18例为1级，7例为2级，2例为3级纤维化。0级纤维化在近端皮质层的平均灌注强度显著高于2级和3级纤维化（1.65米/秒对0.84米/秒，P = 0.008）。0级和1级纤维化之间未发现显著差异。灌注强度与估计肾小球滤过率相关（在远端和近端皮质，Pearson相关系数r分别为0.51，P = 0.001，R² = 0.26；以及0.46，P = 0.001，R² = 0.22）。以组内相关系数表示的皮质近端灌注强度的观察者间一致性为0.69。观察者1的观察者内一致性为0.85，观察者2为0.82。
与无纤维化的移植肾相比，动态彩色多普勒测量评估的灌注强度在2级和3级纤维化的移植肾中显著降低。进一步涉及对接受方案活检的移植肾进行纵向评估的研究将很有意义。
