Evaluation Of Oxygenation Level Of Renal Solid Tumors And The Adjacent Tissues In MR BOLD Imaging:Preliminary Study

ObjectiveTo study the patients with renal solid tumor in MR BOLD imaging, T2* values as a quantitative index were used to assess oxygenation of renal solid tumors and the adjacent tissues, to explore oxygenation differences among renal benign tumors, malignant tumors, and peritumoral renal tissues, and to quest new theory for diagnosis and curative effect Monitoring of renal tumors.Materials and MethodsCollecting continuous patients with renal solid tumor from department of urinary surgery in West China Hospital of Sichuan University from October 2012 to October 2014.The surgical treatments are performed in all patiens,and histopathological results are acquired accurately.There are 31 patients meeting the requirements.20 patients (10 male,10 female)suffered from malignant tumors (clear cell renal carcinoma in 18 cases,and chromophobe renal cell carcinoma in 2 cases),aged 35 to 72,mean tumor diameter 3.53±1.35cm(range:1.6-6.8cm).11 patients(2 male,9 female) suffered from benign tumors (angiomyolipomas in 9 cases, renal oncocytoma in 2 cases),aged 21 to 68,,mean tumor diameter 3.96±1.60cm(range:2.1-7.2cm).All cases underwent 3.0 T MRI(a Tim system, Siemens AG, Erlangen, Germany) examination, including conventional MRI and blood oxygen level-dependent imaging(BOLD).The scaning ranges of conventional MRI include the whole bilateral kidneys, While those of BOLD MRI include the complete tumors.Multiple gradient echo sequence is used in BOLD MRI, and the scanning parameters:TR 127ms TE2.5-59.32 ms, FOV380mmx380mm, matrix 512 x512 NEX= 1, slice 3 mm. Analysises and processings of BOLD MRI images are performed by 2 experienced radiologists blindly. The original images are inputed to Syngo workstation for post-processing to obtain T2* maps.Then Measure the T2* values of the regions-of-interest(ROI),including the ROIs of renal tumors, peritumoral renal cortex and medulla(the same cross-section),contralateral renal cortex and medulla (the same cross-section). The areas of ROIs of tumors are as large as possible,avoiding the areas of artifacts, blood vessels,hemorrhage, necrosis and cystic areas.All statistical analysis were completed by SPSS 17.0 software package, a=0.05. All data were expressed as mean±Standard deviation(X±s).Intra-class correlation coefficient (ICC) is used for analysis of reliability of the data measured by 2 radiologists. According to the results of Normal Distribution Test and Homogeneity Test of Variances,Independent Group T-Test or Mann-Whitney U Test are used respectively.Comparison in the group includes the difference comparisons of the T2* values among renal benign/malignant tumors, peritumoral renal cortex and medulla, and contralateral renal cortex and medulla.Comparison between groups includes the difference comparisons of T2* values of tumors,peritumoral renal cortex and medulla,and contralateral renal cortex and medulla between benign and malignant tumors.Results1. Intra-group comparison:In the group of renal malignant tumors and renal benign tumors, no statistical significant differences are found between the T2* values of peritumoral renal cortex and that of contralateral renal cortex(P>0.05),and between the T2* values of peritumoral renal medulla and that of contralateral renal medulla(P>0.05).The T2* values of renal malignant tumors are higher than those of peritumoral renal medulla(P<0.05),lower than those of peritumoral renal cortex(P<0.05).The T2* values of renal benign tumor are lower than those of peritumoral renal cortex(P<0.05),there is no statistical significant differences between renal benign tumor and peritumoral renal medulla (P>0.05).2.Comparison between groups:The T2* values between renal benign tumor and renal malignant tumor have no statistical significant difference(P>0.05).In the T2* values of peritumoral renal cortex and peritumoral renal medulla,no statistical significant difference are fond between renal malignant tumor and benign tumor(P>0.05).Conclusions1.T2* values of renal malignant tumors are not stable, the range of their oxygenation level is large.2.T2* values of renal benign tumors are below renal cortex, and have no obvious difference with that of renal medulla. Oxygenation level of renal benign tumors are roughly equal to renal medulla.3. The value of BOLD MRI for diagnosis and differential diagnosis of renal benign tumors and renal malignant tumors is not clear.