Preliminary Study On The Application Value Of ¹⁸F-PSMA-1007 PET/MRI For Diagnosis And Biochemical Recurrence Assessment Of Prostate Cancer

Objective:1.Based on the analysis of manual diagnosis,to analyze the clinical application value of fluorine 18-labeled prostate-specific membrane antigen-1007 Positron emission tomography/Magnetic resonance imaging(18F-PSMA-1007 PET/MRI)in the diagnosis of prostate cancer.2.Based on the screening and construction of the radiomics model,to analyze the application value of 18F-PSMA-1007 PET/MRI in the preoperative diagnosis of prostate cancer(PCa).3.Based on manual diagnostic analysis,to analyze the application value of 18F-PSMA-1007 PET/MRI for biochemical recurrence of prostate cancer.Materials and methods:Part I We prospectively collected 42 patients with suspected PCa who underwent whole-body 18F-PSMA-1007 Positron emission tomography/Computed tomography(PET/CT)and prostate 18F-PSMA-1007 PET/MRI in our institution,and a total of 40 PCa lesions and 21 benign prostatic hyperplasia(BPH)lesions were included.Two readers blind to the pathological results independently assessed the images of each suspected PCa lesion.By using histopathology as the reference standard,the diagnostic advantages of 18F-PSMA-1007 PET/MRI compared to biparametric MRI(bpMRI)and 18F-PSMA-1007 PET/CT were investigated.The diagnostic accuracies and cut-off values of the semi-quantitative parameter of the optimal standardized uptake value(SUVmax)and apparent diffusion coefficient(ADC)for the differential diagnosis of PCa were explored.The associations between the SUVmax and ADC of prostate cancer lesion and its International Society of Urological Pathology(ISUP)grade were analyzed.Part Ⅱ We collected the 40 PCa lesions and 21 BPH lesions included in Part Ⅰ,and randomized them to training and validation groups with the ratio of 7:3.Based on the 18F-PSMA-1007 PET/MRI images of the lesions,single sequence(PET,ADC,T2WI),double sequence(PET+ADC,PET+T2WI,ADC+T2WI)and triple sequence(PET+ADC+T2WI)radiomics models were constructed using the radiomics software.The diagnostic accuracies between different sequence radiomics models,and the diagnostic accuracies between radiomics models and manual diagnosis with the same sequence for detecting PCa lesions were respectively compared to screen and construct the optimal radiomics model.Part Ⅲ We prospectively collected 40 patients who underwent whole-body 18F-PSMA-1007 PET/CT and whole-body 18F-PSMA-1007 PET/MRI for biochemical recurrence of PCa after radical prostatectomy.Two readers blind to the clinical data independently assessed the images of each patient.By using follow-up results as the reference standard,the application value of 18F-PSMA-1007 PET/MRI compared with 18F-PSMA-1007 PET/CT for biochemical recurrence were explored.The associations between positive detection results and total serum prostate specific antigen(PSA)level at examination,preoperative total serum PSA level,staging,ISUP grading were analyzed.Results:Part Ⅰ 18F-PSMA-1007 PET/MRI demonstrated significantly greater diagnostic accuracy than 18F-PSMA-1007 PET/CT and bpMRI(P=0.0297,0.0314)with the area under the curve(AUC)of 0.926,0.852,and 0.764,respectively.There were significant differences in SUVmax and ADC values between PCa lesions and hyperplasia lesions(P=0.000,0.000).The combined regression prediction model was establishedas follows:Logit(P)=1.777+0.374×suvmax-5.267×ADC.When the cut-off value was set as 0.9113,the corresponding AUC reached 0.910.The ISUP grade was positively associated with SUVmax(rs=0.454,P=0.003),but not associated with ADC(rs=-0.159,P=0.321).Part Ⅱ Among the single sequence radiomics models,the model RadscorePET based on PET showed the best diagnostic accuracy(AUCtraining=0.923,AUCvalidation=0.897).Among the double sequence radiomics models,the model RadscorePET+ADC based on PET+ADC showed the best diagnostic accuracy(AUCtraining=0.944,AUCvalidation=0.949).The diagnostic accuracy of triple sequence(PET+ADC+T2WI)radiomics model RadscorePET+ADc+T2WI was superior to those of the single sequence radiomics models and the double sequence radiomics models.The diagnostic accuracies of radiomics models RadscorePET+ADC+T2WI,RadscoreADC+T2WI and RadscorePET were superior to those of manual diagnosis with the same sequence.Part Ⅱ Compared to 18F-PSMA-1007 PET/CT,18F-PSMA-1007 PET/MRI showed a similar detection results but with fewer false positives for bone metastases.Only the total serum PSA level at examination showed statistical difference between the positive and negative patients(P=0.001),and it showed positive correlation with the positive results(rs=0.521,P=0.001).The positive detection rate increased with the increase of the total serum PSA level at examination,and it reached 71.88%for the patients with the PSA level at examination was lower than 2.0 ng/mL.Conclusions:18F-PSMA-1007 PET/MRI integrates the targeting role of 18F-PSMA-1007 probe and the high soft tissue resolution of MRI,which is conducive to finding and displaying PCa lesions and their relationship with the surrounding tissues,and reducing the occurrence of false positives and false negatives.18F-PSMA-1007 PET/MRI shows high application value on the diagnosis of PCa lesions.It also performances relatively high value on biochemical recurrence of PCa,even for the patient with a low PSA level.