磁共振成像在糖尿病肾病无创评估中的应用。
The utility of magnetic resonance imaging for noninvasive evaluation of diabetic nephropathy.
机构信息
Division of Nephrology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
Department of Radiology, Lowell General Hospital, Lowell, MA, USA.
出版信息
Nephrol Dial Transplant. 2020 Jun 1;35(6):970-978. doi: 10.1093/ndt/gfz066.
BACKGROUND
Noninvasive quantitative measurement of fibrosis in chronic kidney disease (CKD) would be desirable diagnostically and therapeutically but standard radiologic imaging is too variable for clinical usage. By applying a vibratory force, tissue shear wave stiffness can be measured by magnetic resonance elastography (MRE) that may correlate with progression of kidney fibrosis. Since decreased kidney perfusion decreases tissue turgor and stiffness, we combined newly available three-dimensional MRE shear stiffness measurements with MR arterial spin labeling (ASL) kidney blood flow rates to evaluate fibrosis in diabetic nephropathy.
METHODS
Thirty individuals with diabetes and Stage 0-5 CKD and 13 control individuals without CKD underwent noncontrast MRE with concurrent ASL blood flow measurements.
RESULTS
MRE cortical shear stiffness at 90 Hz was decreased significantly below controls in all CKD stages of diabetic nephropathy. Likewise, ASL blood flow decreased progressively from 480 ± 136 mL/min/100 g of cortical tissue in controls to 302 ± 95, 229 ± 7 and 152 ± 32 mL/min/100 g in Stages 3, 4 and 5 CKD, respectively. A magnetic resonance imaging (MRI) surrogate for the measured glomerular filtration fraction [surrogate filtration fraction = estimated glomerular filtration rate (eGFR)/ASL] decreased progressively from 0.21 ± 0.07 in controls to 0.16 ± 0.04 in Stage 3 and 0.10 ± 0.02 in Stage 4-5 CKD.
CONCLUSIONS
In this pilot study, MRI with ASL blood flow rates can noninvasively measure decreasing kidney cortical tissue perfusion and, with eGFR, a decreasing surrogate filtration fraction in worsening diabetic nephropathy that appears to correlate with increasing fibrosis. Differing from the liver, MRE shear stiffness surprisingly decreases with worsening CKD, likely related to decreased tissue turgor from lower blood flow rates.
背景
在慢性肾脏病（CKD）的诊断和治疗中，非侵入性的纤维化定量测量将是理想的，但标准的放射影像学因临床应用而变化太大。通过施加振动力，磁共振弹性成像（MRE）可以测量组织剪切波硬度，这可能与肾脏纤维化的进展相关。由于肾脏灌注减少会降低组织膨压和硬度，因此我们将新获得的三维 MRE 剪切硬度测量值与磁共振动脉自旋标记（ASL）肾血流量相结合，以评估糖尿病肾病的纤维化。
方法
30 名患有糖尿病且 CKD 分期为 0-5 期的个体和 13 名无 CKD 的对照个体接受了非对比 MRE 检查，并同时进行了 ASL 血流测量。
结果
在糖尿病肾病的所有 CKD 分期中，MRE 皮质剪切硬度在 90Hz 下均明显低于对照组。同样，ASL 血流从对照组的皮质组织 480±136mL/min/100g 逐渐降低至 3 期、4 期和 5 期 CKD 分别为 302±95、229±7 和 152±32mL/min/100g。用于测量肾小球滤过分数的磁共振成像（MRI）替代物[替代滤过分数=估计肾小球滤过率（eGFR）/ASL]从对照组的 0.21±0.07逐渐降低至 3 期的 0.16±0.04和 4-5 期 CKD 的 0.10±0.02。
结论
在这项初步研究中，ASL 血流率的 MRI 可以非侵入性地测量肾脏皮质组织灌注的降低，并且随着 eGFR 的降低，替代滤过分数的降低在恶化的糖尿病肾病中更为明显，这似乎与纤维化的增加相关。与肝脏不同，MRE 剪切硬度随着 CKD 的恶化而令人惊讶地降低，这可能与较低的血流速率导致组织膨压降低有关。
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