不同肾脏深度估算公式校正SPECT/CT肾动态显像对计算活体肾移植供者GFR的影响

Effect of different kidney depth estimation formulas modified SPECT/CT renal dynamic imaging on the calculation of GFR in living kidney transplant donors

目的探讨不同肾脏深度估算公式校正SPECT/CT肾动态显像对计算活体肾移植供者肾小球滤过率(GFR)的影响。方法回顾性分析2011年10月至2017年12月于西安交通大学第一附属医院术前行99Tcm-二亚乙基三胺五乙酸(DTPA)肾动态显像的127名健康肾移植供者的临床资料,其中男性36名、女性91名,年龄(49.2±7.3)岁。以CT实测肾脏深度相对应的GFR为参考标准,分别对Tønnesen公式、Itoh公式计算的肾脏深度及相对应的GFR进行对比研究。不符合正态分布的计量资料以M(Q1,Q2)表示,各公式计算的肾脏深度间的比较采用Wilcoxon秩和检验;采用Spearman相关性分析法及线性回归分析法分析各公式计算的肾脏深度及相对应的左、右肾GFR间的相关性。结果127名健康肾移植供者的CT实测左、右肾脏深度[7.03(6.34,7.67)cm、7.21(6.51,8.13)cm]明显大于Tønnesen公式和Itoh公式计算的左、右肾脏深度[5.66(5.30,6.06)cm、5.70(5.33,6.10)cm]和[6.70(6.33,7.10)cm、6.88(6.52,7.26)cm],且差异均有统计学意义(左肾:Z=−9.53、−3.77,均P<0.001;右肾:Z=−9.73、−4.64,均P<0.001);CT实测左、右肾脏深度与Tønnesen公式、Itoh公式计算的左、右肾脏深度具有正相关性(左肾:r=0.330、0.331,均P<0.001;右肾:r=0.359、0.358,均P<0.001)。CT实测左、右肾脏深度相对应的GFR[46.4(39.9,52.0)ml/min、46.0(40.5,54.9)ml/min]大于Tønnesen公式和Itoh公式计算的左、右肾脏深度相对应的GFR[36.6(33.0,41.9)ml/min、36.2(32.1,40.1)ml/min]和[43.2(39.4,49.8)ml/min、43.8(39.4,48.7)ml/min],且差异均有统计学意义(左肾:Z=−9.52、−3.76,均P<0.001;右肾:Z=−9.73、−4.75,均P<0.001);CT实测肾脏深度与Tønnesen公式、Itoh公式计算的肾脏深度相对应的GFR具有正相关性(左肾:r=0.476、0.476,均P<0.001;右肾:r=0.386、0.539,均P<0.001)。结论Tønnesen公式、Itoh公式计算的肾脏深度相对应的GFR适用于常规肾脏疾病的筛查及评估;对肾脏GFR要求更为严格的肾移植供体者,应以CT实测肾脏深度校正SPECT/CT计算GFR。

Objective To investigate the effect of different kidney depth estimation formulas modified using SPECT/CT renal dynamic imaging on the calculation of the glomerular filtration rate(GFR)in living kidney transplant donors.Methods The clinical data of 127 healthy kidney transplant donors who underwent preoperative 99Tcm-diethylene triamine pentoacetic acid(DTPA)renal dynamic imaging in the First Affiliated Hospital of Xi'an Jiaotong University from October 2011 to December 2017 were retrospectively analyzed.Included 36 males and 91 females,aged(49.2±7.3)years.The computed GFR of kidney depth measured via CT was adopted as the standard reference standard.The Tønnesen and Itoh formulas were used to calculate kidney depth and the corresponding GFR and then compare them with the CT results.The measurement data that did not conform to the normal distribution were expressed as M(Q1,Q2),and the Wilcoxon rank sum test was used to compare between the renal depth calculated by each formula.Spearman correlation analysis and linear regression analysis were used to analyze the correlation between renal depth and the corresponding GFR of lelf and right kidney by each formula.Results The depth of the left and right kidneys from 127 healthy kidney transplant donors measured via CT[7.03(6.34,7.67)cm,7.21(6.51,8.13)cm]was significantly higher than those obtained using the Tønnesen formula[5.66(5.30,6.06)cm,5.70(5.33,6.10)cm]and the Itoh formula[6.70(6.33,7.10)cm,6.88(6.52,7.26)cm],and the differences were statistically significant(left kidney:Z=−9.53,−3.77,both P<0.001;right kidney:Z=−9.73,−4.64,both P<0.001).The renal depth measured via CT was positively correlated with the renal depth calculated using the Tønnesen and Itoh formulas(left kidney:r=0.330,0.331,both P<0.001;right kidney:r=0.359,0.358,both P<0.001).The GFR of left and right kidneys that corresponded to the renal depth measured via CT[46.4(39.9,52.0)ml/min,46.0(40.5,54.9)ml/min]was higher than those obtained using the Tønnesen formula[36.6(33.0,41.9)ml/min,36.2(32.1,40.1)ml/min]and the Itoh formula[43.2(39.4,49.8)ml/min,43.8(39.4,48.7)ml/min],and the differences were statistically significant(left kidney:Z=−9.52,−3.76,both P<0.001;right kidney:Z=−9.73,−4.75,both P<0.001).The CT measurement was positively correlated with the GFR values that corresponded to kidney depth estimates obtained using the Tønnesen and Itoh formulas(left kidney:r=0.476,0.476,both P<0.001;right kidney:r=0.386,0.539,both P<0.001).Conclusions The GFR calculated using the Tønnesen and Itoh formulas are suitable for the routine screening and evaluation of kidney diseases.For kidney transplant donors with more stringent requirements for renal GFR,kidney depth measured via CT should be used to correct the GFR calculated using SPECT/CT.