The Application Of Magnetic Resonance Spectroscopy Imaging On Prediction Of Drug Therapy And Evaluation Of Surgical Prognoses In Pituitary Adenomas

Purpose The aim of current study is to analyze the significance of proton magnetic resonance spectroscopic imaging(MRSI)to predict the response to somatostain analogs(SSA)therapy preoperatively in growth hormone(GH)pituitary adenomas and assessment of prognoses in non-functioning gonadotrophin adenomas(NFGA).Methods Twenty-one patients with a diagnosis of GH pituitary tumorwere positive had undergone surgical resection.Every patients routinely collected age,sex,body mass index(BMI)etc.Magnetic resonance imaging(MRI)and MRSI were performed underwent 1.5T or 3.0T MRI scanner.Three-dimensional MRSI was performed using the multivoxel(MV)point-resolved spectroscopy(PRESS)pulse sequence,repetition time(TR)1,000 ms,echo time(TE)144 ms,voxel size was 7.5mmx7.5mmx10 mm.Selected volumes(100-200cm2)containing as much as possible of areas with abnormal MR signal surrounding the tumor and normal regions.The peak values in the metabolite were acquired by computing the maximum peak values in the range:choline(Ch),3.36-3.21 parts per million(ppm),N-acetylaspartate(NAA),2.18-2.01 ppm,creatine(Cr),3.15-3.0 ppm.The value Ch,Cr,NAA,Ch/Cr,Ch/NAA and NAA/Cr were obtained or calculated by dividing the metabolite values in the spectrum.The GH tumor subtypes diagnosis were performed by electron microscopy(EM).SSTR2/SSTR5/P27/P21 expression was evaluated by immunohistochemistry(IHC)scoring system(IRS).The correlation was analyzed during MRSI data,pathological subtypes and SSTR2 by SPSS19.0 and Graph Pad Prism6.0,in order to predict the value of SSA therapy response.Twenty-eight patients with a diagnosis NFGA who follicule-stimulating hormone(FSH)/Luteinizing hormone(LH)were positive had undergone surgical resection.MRI and MRSI were performed by the same setting.The data was collected,included age,sex,invasion,Knosp grade,etc.Pituitary hormone were inspected on preoperative and the first day of postoperative on morning.In FSH/LH patients,followed by MRI on time.We used SPSS19.0 to predict the value of Knosp grade and evalute prognoses in NFGA.Results Thirteen sparsely granulated(SG)GH tumor patients and five densely granulated(DG)GH tumor patients were enrolled in this study.Receiver operator characteristic(ROC)analysis revealed an area under the curve(AUC)of 0.923 with a P value of 0.007 on Ch/Cr ratio and the AUC of 0.877(P<0.05)on Ch value.The Ch/Cr ratio threshold value is 1.27 with a highest value of sensitivity(92.3%)sum specificity(100%),and the accurate rate is 94.4% on predictive GH tumor subtypes.The Ch value is 3140.5 with a highest value of Sensitivity(69.2%)sum Specificity(100%),on predictive GH tumor subtypes.The Ch/Cr ratio is negative correlate with SSTR2 expression with a p value of 0.02.The Ki-67 values were positive correlated with Ch/Cr ratio(P<0.05)and also positive correlated with T2 signal intense(P<0.05).There is no correlation with age,tumor volume,invasion,SSTR5,P27 and P21 expression.In 28 FSH/LH pituitary adenomas,6 patients were recurred or residual regenerated in followed 4~53 months.The efficiency of MRSI to predicting Knosp grade:the sensitivity,specificity,positive predictive value,negative predictive value and accuracy rate were 80%,84.6%,85.71%,78.57% and 89.28% respectively by Ch/NAA ratio threshold arrived 2.24.Similarly,when the ratio of Ch/Cr threshold was 2.27,the efficiency of MRSI to predicting FSH/LH patients recurrence:the sensitivity,specificity,positive predictive value,negative predictive value and accuracy rate were 83.3%,72.7%,45.45%,94.12% and 75%。Conclusion The MRSI inspection is an effective non-invasive way to provide biochemistry and metabolism informations.It also could predict tumor subtyes,provide the proliferation information and correlate to SST2 expression,Ki-67 value and T2 intensity.When Ch/Cr ratio above 1.27 in GH tumors,it likely a SG adenoma,and if the Ch/Cr ratio more larger,SSTR2 expression maybe more lower,Ki-67 expression maybe more higher,more likely a Hyperintense by T2 signal and poor response to SSA therapy.Ch/Cr ratios may be a image marker to predict response to SSA therapy in pituitary macroadenomas.In FSH/LH tumors,MRSI have a ability to distinguish Knosp grades and assessed prognoses.If the ratio of Ch/NAA larger,it would be more invasive,the Knosp grade 3~4 would more possible.The ratio of Ch/Cr higher,the possibility of postoperative recur more increased.Hence,if the remant was showed,radiotherapy as early as possible.