Clinical Value Of Combined Diffusion-weighted MR Imaging And 3D ~1H MR Spectroscopic Imaging In Prostate Cancer Detection

PartⅠ:Preliminary Study of 3D 1H MR Spectroscopic Imaging of Prostate Cancer in Transitional zonePurpose: To discuss the clinical value of 3D 1H MR Spectroscopic Imaging in the diagnosis of transitional zone (TZ) prostate cancer by analyzing its metabolic characteristics,and in contrast with histopathologic examination. Materials and Methods: Findings in 25 TZ proatate cancer and 35 benign prostate hyperplasia(BPH) who underwent 3D proton MR spectroscopic imaging before biopsy,TURP or radical prostatectomy and who had TZ tumor identified subsequently at pathologic analysis were retrospectively reviewed and who fulfilled all inclusion criteria of no prior hormonal or radiation treatment and at least one lesion at pathologic examination were included. (Cho+Cre)/Cit maps were calculated from 3D 1H MR spectroscopic imaging data. ROIs in the PZ identified by matching pathologic slides with T2WI were overlaid on (Cho+Cre)/Cit maps. Areas under the ROC curves were used to evaluate accuracy. In these 25 patients, the ratios of (Cho+Cre)/Cit were compared in tumor and control tissues. Results: The mean value of (Cho+Cre)/Cit was significantly different between TZ cancer and control tissues(P < 0.001). In distinguishing malignant ROIs, (Cho+Cre)/Cit (0.98±0.004; P<0.01) . Conclusion: TZ cancer has a metabolic profile that is different from that of benign TZ tissue; The (Cho+Cre)/Cit can differentiate TZ cancer from benign TZ tissue. PartⅡ:Clinical Value of Combined 3D 1H MR Spectroscopic Imaging and Diffusion-weighted MR Imaging of Prostate CancerPurpose: To retrospectively measure the (Cho+Cre)/Cit ratio with 3D 1H MRSI and the ADC with DWI in ROIs drawn over benign and malignant peripheral zone (PZ) and TZ prostatic tissue and to assess (Cho+Cre)/Cit, ADC, and combined (Cho+Cre)/Cit and ADC for identifying malignant ROIs, with histopathologic examination as the reference standard. Materials and Methods: 61 men identified prostate cancer (mean age, 77.43 years; range, 57-88 years) who underwent 1.5T MR imaging before biopsy,TURP or radical prostatectomy and who fulfilled all inclusion criteria of no prior hormonal or radiation treatment and at least one lesion at pathologic examination were included. (Cho+Cre)/Cit maps of (choline plus creatine)/citrate were calculated from 3D 1H MR spectroscopic imaging data, and ADC maps were generated from diffusion-weighted MR imaging data. ROIs in both PZ and TZ identified by matching pathologic slides with T2WI were overlaid on (Cho+Cre)/Cit and ADC maps. Areas under the ROC curves (AUC) were used to evaluate accuracy. Results: The mean ADC(0.86±0.18)×10-3 mm2/s, and mean (Cho+Cre)/Cit (2.44±1.25) for malignant ROIs differed significantly from the mean ADC( 1.46±0.46 )×10-3 mm2/s, ( 1.79±0.29 )×10-3 mm2/s, and mean (Cho+Cre)/Cit ,(0.87±0.17),(0.54±0.12) for benign (BPH and PZ) ROIs (P<0.01 for both). In distinguishing malignant ROIs, combined ADC and (Cho+Cre)/Cit (AUC = 0.989) and (Cho+Cre)/Cit alone (AUC = 0.987; P<0.01) performed significantly better than ADC alone (AUC = 0.966; P < 0.01). Conclusion: The (Cho+Cre)/Cit and ADC can differentiate between benign and malignant ROIs in both PZ and TZ.