The diagnostic ability of biexponential diffusion-weighted imaging (DWI) for organ-conifned prostate cancer in peripheral zone：compared to monoexponential DWI / 中国癌症杂志

Background and purpose:With the widespread use of screening of prostate-specific antigen (PSA) levels, prostate cancers at organ-conifned stage are increasing in newly diagnosed cases. However, some defects remain in conventional monoexponential diffusion-weighted imaging (DWI) for differentiating organ-conifned prostate cancer from benign lesions. Therefore, the aim of this study was to obtain biexponential apparent diffusion parameters of prostate organ-conifned cancer, chronic prostatitis in peripheral zone (PZ) and normal PZ tissue, and to compare with monoexponential apparent diffusion coeffcient (ADC) for differentiating prostate cancer from prostatitis lesions. Methods:Sixteen patients with pathologically confirmed prostate organ-confined cancer in PZ, 14 with prostatitis underwent conventional (b-factors 0, 1 000 s/mm2) and 10b-factors (0-3 000 s/mm2) diffusion-weighted imaging (DWI).The monoexponential ADC value and biexponential parameters fast ADC (ADCf), fraction of ADCf (f), slow ADC (ADCs) value for prostate cancer, prostatitis and normal tissues were calculated and compared. Receiver operating characteristic analysis was performed for those parameters.Results:Biexponential and monoexponential parameters were obtained for 18 prostate cancers, 18 prostatitis and 37 normal PZ tissues. The ADC value of prostate cancer tissues was remarkably lower [(0.83±0.11)×10-3 mm2/s] than that of other tissues (P0.01), but the AUC off and ADCs in differ-entiating cancer from prostatitis (0.83 and 0.80) were signiifcantly lower than that of ADC (P<0.01).Conclusion:The biexponential DWI provided additional tissue characterization parameters for different prostate tissues. ADCf yielded comparable accuracy with ADC in identiifcation of prostate organ-conifned cancer. The biexponential parameter could further improve the diagnostic effcacy.

3.0T MRI Multi-b-value Diffusion Weighted Imaging in the Differential Diagnosis of Female Pelvic Benign and Malignant Lesions / 中国医学影像学杂志

Purpose To explore the diagnostic value of double exponential model for pelvic lesions using 3.0T MRI for the diagnosis of pelvic lesion. Materials and Methods Fifty patients with pelvic lesions (30 benign cases and 20 malignant cases) underwent MR750-diffusion weighted imaging (DWI) scans, with b values of 0, 50, 300, 600, 800 and 1200 s/mm2, Functool-MADC software was used on AW 451 workstations for data processing, Slow ADC value, Fast ADC value, Standard ADC value, Fraction of fast ADC value were recorded and compared between benign and malignant lesions, and Standard ADC images were fused with axial T2 fat-suppressed images. Results Slow ADC values [(1.83±0.86)×10-3 mm2/s] and Standard ADC values [(1.79±0.78)×10-3 mm2/s] of benign lesions were larger than those of the malignant lesions [Slow ADC values:(1.05±0.31)×10-3 mm2/s;Standard ADC values:(1.13±0.39)×10-3 mm2/s] (t=3.90, 3.51;P<0.01), and the difference of Slow ADC value was largest between benign and malignant lesions. Slow ADC values of both benign and malignant lesions were significantly less than the Fast ADC values [benign:Slow ADC value=(1.83±0.86)×10-3 mm2/s, Fast ADC value=(16.95±8.63)×10-3 mm2/s; malignant: Slow ADC value=(1.05±0.31)×10-3 mm2/s, Fast ADC value=(15.12±9.90)×10-3 mm2/s] (t=-10.40,-6.29;P<0.01). Conclusion Double exponential decay model is capable of differentiating benign and malignant pelvic tumors, thus is of great significance for clinical preoperative diagnosis.

Biexponential Apparent Diffusion Coefficients Values in the Prostate: Comparison among Normal Tissue, Prostate Cancer, Benign Prostatic Hyperplasia and Prostatitis

OBJECTIVE: To investigate the biexponential apparent diffusion parameters of diverse prostate tissues and compare them with monoexponential apparent diffusion coefficient (ADC) value in the efficacy to discriminate prostate cancer from benign lesions. MATERIALS AND METHODS: Eleven healthy volunteers and 61 patients underwent a conventional (b-factors 0, 1000 s/mm2) and a 10 b-factor (0 to 3000 s/mm2) diffusion-weighted imaging (DWI). The monoexponential ADC value and biexponential parameters of fast ADC (ADCf), fraction of ADCf (f), slow ADC (ADCs) value for 29 prostate cancer, 28 benign prostatic hyperplasia (BPH), 24 prostatitis lesions and normal tissue were calculated and compared. Receiver operating characteristic analysis was performed to determine the sensitivity, specificity and optimal cut-off points. RESULTS: Prostate cancer had lower ADC, ADCf, f, and ADCs than all other tissues (p 0.05), but the AUC of f and ADCs in differentiating cancer from BPH (0.73 and 0.81) and prostatitis (0.88 and 0.91) were significantly lower than ADC (all p < 0.05). CONCLUSION: The biexponential DWI appears to provide additional parameters for tissue characterization in prostate, and ADCf helps to yield comparable accuracy with ADC in differentiating cancer from benign lesions.