Diffusion-weighted endorectal MR imaging at 3T for prostate cancer: correlation with tumor cell density and percentage Gleason pattern on whole mount pathology

Abstract

Objective To determine if tumor cell density and percentage of Gleason pattern within an outlined volumetric tumor region of interest (TROI) on whole-mount pathology (WMP) correlate with ADC values on corresponding TROIs outlined on pre-operative MRI. Methods Men with biopsy-proven prostate adenocarcinoma undergoing multiparametric MRI (mpMRI) prior to prostatectomy were consented to this prospective study. WMP and mpMRI images were viewed using 3D Slicer and each TROI from WMP was contoured on the high b-value ADC maps (b0, 1400). For each TROI outlined on WMP, TCD (tumor cell density) and the percentage of Gleason pattern 3, 4, and 5 were recorded. The ADCmean, ADC10th percentile, ADC90th percentile, and ADCratio were also calculated in each case from the ADC maps using 3D Slicer. Results Nineteen patients with 21 tumors were included in this study. ADCmean values for TROIs were 944.8 ± 327.4 mm2/sec vs. 1329.9 ± 201.6 mm2/sec for adjacent non-neoplastic prostate tissue (p<0.001). ADCmean, ADC10th percentile, and ADCratio values for higher grade tumors were lower than those of lower grade tumors (mean: 809.71 and 1176.34 mm2/sec, p=0.014; 10th percentile: 613.83 and 1018.14 mm2/sec, p=0.009; ratio: 0.60 and 0.94, p=0.005). TCD and ADCmean (ρ= −0.61, p=0.005) and TCD and ADC10th percentile (ρ= −0.56, p=0.01) were negatively correlated. No correlation was observed between percentage of Gleason pattern and ADC values. Conclusion DWI MRI can characterize focal prostate cancer using ADCratio, ADC10th percentile, and ADCmean, which correlate with pathological tumor cell density.

Comparison of quantitative apparent diffusion coefficient parameters with prostate imaging reporting and data system V2 assessment for detection of clinically significant peripheral zone prostate cancer

“…Our results comparing ADC metrics between tumor and normal tissue are similar to those previously reported, with significantly lower mean ADC T than those in healthy-appearing PZ prostate tissue (ADC N ) [11,31,32]. Various ADC metrics have been investigated, including ADC mean and ADC ratio , for detection of csPC.…”

Risk Stratification Among Men With Prostate Imaging Reporting and Data System version 2 Category 3 Transition Zone Lesions: Is Biopsy Always Necessary?

“…The lesion ADC was an important predictor of clinically significant PCA on both univariate and multivariate analyses, in keeping with multiple prior studies that have documented an inverse relationship between lesion ADC and tumor grade [15–18]. Moreover, although PI-RADSv2 does not explicitly endorse a quantitative ADC assessment in the TZ, it does allow upgrading of a lesion with a category of 3 based on the presence of markedly restricted diffusion (coupled with size > 1.5 cm or invasive behavior).…”

Multiparametric MRI Apparent Diffusion Coefficient (ADC) Accuracy in Diagnosing Clinically Significant Prostate Cancer

“…The decrease in ADC value in high GS disease can be explained by the high level of tumor cellularity, which is representative of tumor aggressiveness; indeed, tumor cellularity is one of the major determinants for tumor grade of prostate cancer and an inverse relationship between tumor cellularity and ADC value has been previously reported (2)(3)(4)(5)(6)(7)(8)(9). In detail, DWI is the only functional imaging technique that gives information about cellular microstructure and changes in neoplastic tissue that may be pointed out by DWI, reporting more restricted movement of water characterized by decreased ADC values.…”

“…[2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], clinical stage T1c and median GS equal to 6.8 (range=6-9) underwent radical retropubic prostatectomy (RRP) for biopsy of clinically significant PCa (GS ≥6 and/or more than 2 positive cores and/or a greatest percentage of cancer for each core >50%) (10); 16/44 (36.6%) patients previously enrolled in Active Surveillance (AS) program were upgraded at confirmatory biopsy and 28/44 (63.4%) men underwent repeat saturation biopsy (median=30 cores; range=28-34 cores) for persistent suspicious cancer. Previously, all patients about 10 days before prostate biopsy underwent pelvic mpMRI and two radiologists blinded to pre-imaging clinical parameters evaluated the mpMRI data separately and independently.…”

“…Maps of the apparent diffusion coefficient (ADC), computed from diffusion-weighted imaging (DWI), provide a quantitative parameter to evaluate prostate regions with suspicion of PCa. In neoplastic tissue, ADC values decrease from the one measured in normal prostatic tissue and some studies have demonstrated a possible differentiation in PCa grading, according to Gleason score (GS) classification (2)(3)(4)(5)(6)(7)(8)(9). Currently, there are no defined thresholds that have been accepted by the radiological scientific community to discriminate healthy and diseased patients as well as to differentiate PCa grading.…”