肾脏弛豫率的参考值及其与不同场强的相关性

Reference range of renal relaxation rate and its correlation with different magnetic field intensities

目的探讨肾脏弛豫率(R_2~*)的参考值及其与不同场强的相关性。方法将105名志愿者分为A组(90名)和B组(15名),其中A组应用Philips 3.0T MRI扫描,B组接受Siemens 3.0T和Philips 1.5T MRI扫描,扫描间期间隔2 h。在志愿者扫描前与扫描结束时均采用3台MRI扫描标准水模。采集梯度多回波(T2*)序列,测算志愿者肾皮质、髓质与水模的R_2~*值,比较不同场强与机型扫描所得肾脏或水模R_2~*值,分析R_2~*参考值及其与不同场强的相关性。结果志愿者扫描前与扫描结束时,Siemens 3.0T和Philips 3.0T MRI扫描水模所得R_2~*值均高于Philips 1.5T MRI(均P<0.05),Siemens 3.0T和Philips 1.5T MRI扫描水模所得的R_2~*值呈直线相关(r=0.995,P<0.05)。100名志愿者的髓质R_2~*高于皮质(P<0.05)。Siemens 3.0T MRI扫描皮质、髓质所得的R_2~*值及其差值大于Philips 1.5T MRI(P<0.05),Siemens 3.0T MRI与Philips 1.5T MRI扫描皮髓质所得的R_2~*值均无相关性(P>0.05)。结论肾髓质R_2~*高于皮质,不同场强间肾R_2~*无相关性,而不同场强间水模R_2~*高度相关。

Objective To explore the reference range of renal relaxation rate（ R2^＊） and its correlation with different magnetic field intensities. Methods A total of 105 volunteers were divided into group A（ n = 90） and group B（ n = 15）. Group A received MRI scanning using Philips Healthcare System（ 3. 0 T）,while group B received MRI scanning using Siemens Healthcare System（ 3. 0 T） and Philips Healthcare System（ 1. 5 T）,with a two-hour scanning interval. The water phantom scanning was performed using the three MRI scanners above before and after the volunteers＇ scanning. Multiple gradient-echo（ T2＊） sequence was collected,and the R2^＊ values of phantom,renal cortex and medulla were determined among the volunteers. The R2^＊ values of kidney/phantoms were compared among different field intensities,or among different MRI scanners. The correlation of the reference range of R2^＊ values with different field intensities was analyzed. Results Before and after the volunteers＇ scanning,the R2^＊ values of phantoms acquired by 3. 0 T Siemens Scanner and 3. 0 T Philips Scanner were higher than that by 1. 5 T Philips Scanner（ all P 〈0. 05）,and there was a rectilinear correlation between R2^＊ values of phantoms acquired by 3. 0 T Siemens Scanner and 1. 5 T Philips Scanner（ r = 0. 995,P 〈0. 05）. The medullary R2^＊ value was higher than the cortical value among the 100 volunteers（ P 〈0. 05）. The medullary and cortical R2^＊ values acquired by 3. 0 T Siemens Scanner and their difference value were higher than those by 1. 5 T Philips Scanner（ P〈 0. 05）,and no correlation was found between the medullary or cortical R2^＊ values acquired by 3. 0 T Siemens Scanner and 1. 5 T Philips Scanner（ P 〉0. 05）. Conclusion The R2^＊ value of renal medulla is higher than that of renal cortex,there is no correlation among the renal R2^＊ values scanned with different field intensities,however,a high correlation is seen among phantom the R2^＊ values scanned with different field intensities.