Thoeny Harriet C, De Keyzer Frederik, Oyen Raymond H, Peeters Ronald R
Department of Radiology, University Hospitals Leuven, Leuven, Belgium.
Radiology. 2005 Jun;235(3):911-7. doi: 10.1148/radiol.2353040554. Epub 2005 Apr 21.
To prospectively evaluate feasibility of diffusion-weighted (DW) magnetic resonance (MR) imaging in assessment of renal function in healthy volunteers and patients with various renal abnormalities and to prospectively evaluate reproducibility of DW MR imaging in volunteers.
Study protocol was approved by local ethics committee; informed consent was obtained. Eighteen healthy volunteers and 15 patients underwent transverse fat-saturated echo-planar DW MR imaging of the kidneys during normal breathing. Freehand regions of interest were delineated in the cortex and medulla of the kidneys. The following apparent diffusion coefficient (ADC) values were calculated: ADC of all b values (ADC(avg)), ADC of low b values (b = 0, 50, 100 sec/mm2; ADC(low)), and ADC of high b values (b = 500, 750, 1000 sec/mm2; ADC(high)). These values were calculated to differentiate influence of perfusion and diffusion. Reproducibility was assessed by repeating the same protocol in five randomly selected volunteers after 6 months. For statistical analysis, Student t tests were used.
In all volunteers, ADC(avg) and ADC(high) were significantly higher in the cortex than in the medulla (P < .001). No difference between the cortex and medulla could be observed for ADC(low). Patients with renal failure had significantly lower ADC(avg) (P < .001, P = .004), ADC(low) (P = .02, P = .03), and ADC(high) (P = .02, P = .04) of cortex and medulla, respectively, than did volunteers. In the patient with pyelonephritis, all ADC values of cortex and medulla were substantially lower compared with the contralateral side, whereas patients with ureteral obstruction showed varying degrees of difference in all ADC values compared with the contralateral side. No statistically significant changes were found in the repeat study of the volunteers.
DW MR imaging is feasible and reproducible in the assessment of renal function, as shown in our initial experience with a small number of patients and volunteers.
前瞻性评估扩散加权（DW）磁共振（MR）成像在评估健康志愿者和各种肾脏异常患者肾功能方面的可行性，并前瞻性评估DW MR成像在志愿者中的可重复性。
研究方案经当地伦理委员会批准；获得知情同意。18名健康志愿者和15名患者在正常呼吸期间接受了肾脏的横向脂肪饱和回波平面DW MR成像。在肾脏的皮质和髓质中徒手勾勒感兴趣区域。计算以下表观扩散系数（ADC）值：所有b值的ADC（ADC(avg)）、低b值（b = 0、50、100秒/平方毫米；ADC(low)）的ADC以及高b值（b = 500、750、1000秒/平方毫米；ADC(high)）的ADC。计算这些值以区分灌注和扩散的影响。6个月后在5名随机选择的志愿者中重复相同方案来评估可重复性。进行统计分析时使用了Student t检验。
在所有志愿者中，皮质的ADC(avg)和ADC(high)显著高于髓质（P <.001）。ADC(low)在皮质和髓质之间未观察到差异。肾衰竭患者皮质和髓质的ADC(avg)（P <.001，P =.004）、ADC(low)（P =.02，P =.03）和ADC(high)（P =.02，P =.04）分别显著低于志愿者。在肾盂肾炎患者中，皮质和髓质的所有ADC值与对侧相比均显著降低，而输尿管梗阻患者与对侧相比所有ADC值显示出不同程度的差异。志愿者的重复研究未发现统计学上的显著变化。
如我们在少数患者和志愿者中的初步经验所示，DW MR成像在评估肾功能方面是可行且可重复的。
