| Part One Diagnostic efficacy of 68Ga-PSMA PET/MR in prostate cancerPurpose The purpose of this section is to investigate the diagnostic efficacy of 68 GaPSMA PET/MR imaging in patients with primary prostate cancer(PCa)and post-radical PCa surgery.Methods To analyze the imaging data of subjects who underwent 68Ga-PSMA PET/MR imaging in our hospital between 2020.07-2021.12.Group I was patients with primary diagnosis of PCa.Inclusion criteria were:(i)suspected PCa or confirmed PCa by pathological results of prostate puncture;(ii)68Ga-PSMA PET/MR imaging was performed in our department;(iii)no local or systemic treatment was performed.Group II was patients after radical PCa surgery.Inclusion criteria were:(i)after radical PCa surgery;(ii)68GaPSMA PET/MR imaging was performed in our department.Exclusion criteria for both groups:(i)complete clinical information could not be obtained;(ii)those who lacked informed consent.The PET/MR examination was performed approximately 60 min after the subject was injected intravenously with 68Ga-PSMA-11 imaging agent.The images were analyzed by two experienced nuclear medicine physicians,and the maximum standardized uptake value(SUVmax)and apparent diffusion coefficient(ADC)were measured for each type of lesion.To analyze the consistency between the diagnostic results of 68Ga-PSMA PET/MR imaging and the pathological results or the final clinical diagnosis(based on the comprehensive analysis of clinical data),to analyze the correlation between clinical data and imaging data,and draw the receiver operating characteristic curve(ROC curve)and calculate the area under the curve(AUC)to analyze the diagnostic value of each clinical and imaging parameter for positive lesions.To compare the TNM staging concordance between 68 GaPSMA PET/MR imaging diagnosis and pathology after radical surgery.To analyze the effect of androgen deprivation therapy(ADT)on PSMA expression.Results A total of 190 individuals were enrolled in Group I.Nine of them had a final pathological or clinical diagnosis of non-PCa,and 181 had a pathologically confirmed diagnosis of PCa(107 were treated with radical PCa surgery).From the case perspective,the diagnostic sensitivity,specificity,PPV,NPV,and Kappa coefficient of agreement with pathological findings of 68Ga-PSMA PET/MR imaging were 99.45%,77.78%,98.90%,87.50%,and 0.815,respectively.There were significant differences in age,serum PSA levels,SUVmax,SUVmean,MTV,PSMA expression load and ADCmin between patients with intermediate and high prognostic risk(all P values < 0.05).Serum PSA levels and pathological Gleason classification grouping correlated with SUVmax,SUVmean,MTV,PSMA expression load and ADCmin.The AUCs of SUVmax,SUVmean,PSMA expression load and ADCmin were 0.980,0.977,0.857 and 0.862,respectively.The overall concordance rate of 68Ga-PSMA PET/MR imaging for pathological T-staging after radical surgery was 83.18%(89/107),and lymph node metastases could be detected in 73 and distant metastases in 48.Comparison with postoperative lymph node pathology revealed a higher percentage of lymph node dissection and a higher chance of detecting positive lymph nodes in patients with a 68Ga-PSMA PET/MR diagnosis of stage T3,which can help clinicians determine whether additional local or systemic therapy is needed for patients after radical PCa surgery.Due to positive lymph nodes or distant metastases detected by 68Ga-PSMA PET/MR,the originally proposed radical PCa treatment plan was changed to ADT combination therapy in72.6% and 81.3% of patients,respectively.There were 64 patients in Group 2,and 68 GaPSMA PET/MR imaging detected a total of 39(60.9%)with recurrence or metastasis.The detection rates of PSMA PET/MR imaging in different PSA level intervals were 21.4% for PSA<0.2ng/ml,46.7% between 0.2 and 0.5ng/ml,72.2% between 0.5 and 2.0ng/ml,and94.1% for PSA>2.0ng/ml.Patients after radical surgery were grouped according to whether or not they were treated with ADT,and there were no significant differences between the two groups in overall detection rates,serum PSA levels,and detection rates of each type of metastatic lesion and SUVmax(all P values > 0.05).Conclusion 68Ga-PSMA PET/MR imaging has high clinical value in PCa lesion detection,TNM staging,postoperative recurrence detection and guiding the development of treatment plans.In particular,the T-stage provides detailed anatomical information that can help clinicians determine whether lymph node dissection and postoperative adjuvant systemic therapy are required for patients proposed for radical PCa surgery;In NM staging,detection of lymph nodes or distant metastases changed the patient’s proposed radical PCa treatment plan.The effect of ADT treatment on PSMA expression requires further prospective studies.Part Two Diagnostic value of combined 68Ga-PSMA PET/MR and 18 FFDG PET/CT imaging in primary diagnosis of high-risk prostate cancerPurpose The purpose of this part is to study the diagnostic value of combined 68 GaPSMA PET/MR and 18F-FDG PET/CT imaging in primary diagnosis of high-risk prostate cancer(PCa).Methods Prospective analysis of imaging data of subjects who underwent simultaneous68Ga-PSMA PET/MR and 18F-FDG PET/CT imaging at our hospital during 2020.07-2021.12.Inclusion criteria:(i)68Ga-PSMA PET/MR and 18F-FDG PET/CT imaging were performed in our hospital(no more than 2 weeks apart);(ii)no treatment was performed;(iii)prostate puncture or radical PCa treatment was performed in our urology department due to suspected or confirmed high-risk PCa(PSA>20ng/ml or Gleason>7 score or c T≥3stage).Exclusion criteria:(i)inability to obtain complete clinical data;(ii)patients unwilling to undergo dual tracer imaging and unwilling to sign an informed consent form.The subjects underwent 68Ga-PSMA PET/MR and 18F-FDG PET/CT examinations on different days,and two nuclear medicine physicians analyzed each of the two examinations,and measured the maximum standardized uptake value(SUVmax)of the two imaging agents for each type of lesion,and the SUVmax of the intraocular muscle,and the tumor-to-background ratio(TBR)was calculated.The pathological and imaging parameters were counted separately according to the anatomical quadrants of the prostate.To compare the separate and combined test efficacy of the two imaging techniques for primary diagnosis of high-risk PCa and to explore the performance of the two tests in the detection of multifocal and heterogeneous lesions in patients with primary high-risk PCa.Results A total of 39 patients were enrolled,of whom 2 had postoperative pathology of non-PCa and 37 were patients with primary PCa.From the case perspective,the diagnostic sensitivity,specificity,PPV,and NPV of 68Ga-PSMA PET/MR imaging were 100%,50%,97.37%,100%,and 0.655 in agreement with the pathological findings Kappa coefficient,respectively;18F-FDG PET/CT imaging was 67.57%,50%,96.15%,7.69% and 0.049;the combined diagnosis was 100% for all the above indicators.From a lesion perspective,the AUCs of the two imaging techniques SUVmax for the diagnosis of PCa were 0.825 and 0.648.68Ga-PSMA PET/MR imaging was significantly better than 18F-FDG PET/CT imaging for the detection of multifocal and heterogeneous lesions(27.03% vs.10.81%),but the latter can still detect multifocal patients and lymph node metastases that were not detected by the former.Semi-quantitative analysis can also observe a higher rate of agreement between68Ga-PSMA PET/MR imaging and zoned pathology,while in areas that do not match pathology on PSMA PET,the uptake mode on 18F-FDG PET/CT imaging can play a role in differential diagnosis,and the combined application of both imaging agent uptake modes can identify more positive lesions that are consistent with pathology.Comparing the difference in uptake of the two imaging agents between the specific pathological type PCa(ductal adenocarcinoma,small cell carcinoma,etc.)and prostate alveolar adenocarcinoma,PSMA uptake was lower and FDG uptake was higher in the former,but there was no statistical difference after test analysis.Conclusion 68Ga-PSMA PET/MR showed better performance than 18F-FDG PET/CT in lesion detection,clinical staging,and tumor heterogeneity expression in patients with primary diagnosis of high-risk PCa,but the latter could detect multifocal patients and lymph node metastases that were not detected by the former,joint diagnostic effectiveness was improved.68Ga-PSMA PET/MR combined with 18F-FDG PET/CT imaging allows for timely and correct characterization of lesion heterogeneity and is more likely to benefit PCa patients with a clinical diagnosis of high-risk but mild PSMA-11 uptake. |
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