肾脏皮髓质的分界、对比度及CT峰值与单肾功能相关性的64层螺旋CT研究

The 64-MSCT study of relationship between renal corticomedullary differentiation, contrast between renal cortex and medulla, renal cortex and medulla CT peak value with the single renal function in hydronephrotic kidney

目的探讨64层MSCT灌注扫描中正常肾与梗阻性肾积水时积水肾皮髓质分界（CMD）、肾皮髓质对比度（CMC）及皮髓质CT峰值的变化规律，并探讨其与单肾功能的相关性。方法选择36例梗阻性肾积水患者，对其进行64层MSCT灌注扫描和SPECT肾动态显像检查，并将患者按SPECT测定的肾小球滤过率（GFR）水平分为正常组、轻度与重度肾功能减退组。分析CMD情况，并分别测量皮质峰值时刻的皮质及髓质CT值，计算CMC。采用方差分析比较3组间皮髓质CT峰值的差异，并分别将CMC及肾皮髓质CT峰值与GFR进行相关性分析。结果（1）CMD：正常组24个100％CMD清晰。轻度肾功能减退组21个中，14个（66．7％）CMD清晰，2个CMD模糊但仍可见，5个CMD部分可见。重度肾功能减退组27个中，7个CMD清晰，5个CMD模糊但仍可见，15个CMD部分可见。（2）正常组、轻度和重度肾功能减退组CMC分别为0．62±0．20、0．52±0．1g和0．37±0．11，CMC与GFR呈正相关（r=0．536，P〈0．05）。（3）CT峰值：正常组肾皮质为（133±22）HU，肾髓质为（104±16）HU；轻度肾功能减退组肾皮质为（91±29）HU，肾髓质为（76±25）HU；重度肾功能减退组肾皮质为（68±24）HU，肾髓质为（57±21）HU。5组间差异均有统计学意义（F值分别为42．76和32．68，P值均〈0．05）。肾皮质、髓质CT峰值均与GFR呈正相关（r值分别为0．672和0．623，P值均〈0．05）。结论梗阻性肾积水肾功能减退时CMD与CMC及。肾皮髓质CT峰值均降低；肾脏CMC与肾皮质及髓质CT峰值改变与GFR具有正相关关系，对预测单侧肾脏功能有一定临床价值。

Objective To study 64-MSCT perfusion imaging features about renal cortieomedullary differentiation, contrast between renal cortex and medulla（ CMC ） , renal cortex and medulla CT peak value in normal and hydronephrotic kidneys, and to explore the relationship between them and the unilateral renal function. Methods Thirty-six patients with obstructive nephrohydrosis underwent 64-MSCT perfusion scanning. The split renal glomerular filtration rates （GFR） of their kidneys were measured by SPECT renal dynamic imaging. The 72 kidneys were divided into groups of normal renal function group, mild and severe renal impairment groups according to GFR. Renal corticomedullary differentiation on CT images was graded as clear, obscure, part clear. The CT intensity of cortex and medulla was measured in order to calculate contrast between renal cortex and medulla （CMC）. Using Pearson correlation test, the correlation between them and renal GFR were examined. Results （ 1 ） In the 24 kidneys of normal group, all kidneys showed clear CMD. In the 21 kidneys of mild renal impairment group, 14 kidneys showed clear CMD, 2 showed obscure CMD and 5 showed part clear of CMD. In the 27 kidneys of severe renal impairment group, 7 kidneys showed clear CMD, 5 showed obscure CMD and 15 showed part clear of CMD, （2）The CMC of normal group was 0. 62 ±0. 20, while it was 0. 52 ±0. 14 and 0. 37 ±0. 11 for mild renal impairment group and severe renal impairment group CMC respectively. The CMC had positive linear correlation with GFR （r =0. 536,P 〈 0. 05 ）. （3）The renal cortex and medulla CT peak value of normal group were （133 ± 22） and （104 ± 16）HU; The renal cortex and medulla CT peak value of mild renal impairment group were （ 91 ± 29 ） and （ 76 ± 25 ） HU ; The renal cortex and medulla CT peak value of severe renal impairment group were （ 68 ± 24 ） and （57± 21 ） HU （ F = 42. 76 and 32. 68, P 〈 0. 05 ）. The renal cortex and medulla CT peak value had positive linear correlation with GFR （ r = 0. 672 and 0. 623, P 〈 0. 05 ）. Conclusions The CMC and the renal cortex and medulla CT peak value all degrade when kidney function decreases in patients with obstructive nephrohydrosis. The CMC and the renal cortex CT peak value of obstructive nephrohydrosis had positive linear correlation with GFR. So they are valuable in evaluating the unilateral renal function of hydronephrosis.