Apparent diffusion coefficient: Prostate cancer versus noncancerous tissue according to anatomical region

Abstract

Purpose: To evaluate diagnostic performance of apparent diffusion coefficient (ADC) in differentiating prostate cancer from noncancerous tissue according to anatomical region. Materials and Methods:In 47 patients with diffusionweighted-MR (b-value, 0 and 1000 sec/mm 2 ) on a 1.5 T unit, ADCs were measured in prostate cancer and in three noncancerous tissues (transitional zone, peripheral zone, and prostatic base). Diagnostic performance of ADC for differentiating cancer from noncancerous tissue was evaluated using receiver-operating-characteristics (ROC) analysis.Results: Mean ADC of prostate cancer (0.963 ϫ 10 Ϫ3 mm 2 /s) was lower than those of all noncancerous tissues (P Ͻ 0.001). In noncancerous tissue, ADC differed according to anatomical region (peripheral zone, 1.572 ϫ 10 Ϫ3 mm 2 /sec; transitional zone, 1.441 ϫ 10 Ϫ3 mm 2 /sec; prostatic base, 1.146 ϫ 10 Ϫ3 mm 2 /sec) (P Ͻ 0.01). ADC was lower in prostate cancer than in all noncancerous tissues in 34 (72%) patients. Area under the ROC curve for differentiating cancer from noncancerous tissue in prostatic base (0.725) was less than those for differentiating cancer from noncancerous tissue in peripheral (0.952) and transitional zones (0.906) (P Ͻ 0.05). Sensitivity differed according to anatomical region (peripheral zone, 98%; transitional zone, 82%; prostatic base, 66%) (P Ͻ 0.05). Conclusion:Variable ADC in noncancerous tissue according to anatomical region may limit diagnostic performance of ADC for cancer detection.

Diffusion weighted imaging in prostate cancer

“…In a study of 47 patients, Kim and colleagues [25] found that the mean ADC value for normal TZ (1.441×10 −3 mm 2 /s) was significantly higher than for the PZ (1.146×10 −3 mm 2 /s). In that study, sensitivity of ADC values for PC in the peripheral zone was 98%, compared with 81% in the transitional zone (p=0.01), although there were no significant differences in specificity.…”

“…Miao et al [16] showed that the sensitivity and specificity rates for T2WI was 76% and 70% respectively, compared with 86% and 80% for DWI. Combined T2WI and DWI yield slightly better results, with reported sensitivity and specificity rates of 45-89% and 61-97% respectively, compared with 74-85% and 57-95% respectively for DWI alone and 25-87% and 57-92% respectively for T2WI alone [12,15,[17][18][19][20][21][22][23][24][25][26].…”

16 T Diffusion microimaging of fixed prostate tissue: Preliminary findings

“…However, in the heterogeneous central zone assignment of diffusion characteristics to tissue type has been equivocal. Attempts to measure diffusion anisotropy in vivo have also produced equivocal results (2)(3)(4)(5)(6)(7)(8).…”

Value of Diffusion Tensor Imaging of Prostate Cancer: Comparison with Systemic Prostate Biopsy

“…The time between the MR examination and systemic 12 biopsy was within one week. Twenty-three of 31 patients had histopathologically proven adenocarcinoma with a Gleason score of 6.2 (range, [3][4][5][6][7][8][9][10] Table 1). Only a slight overlap was observed between the positive and negative cores.…”

“…The use of multiple diffusion gradient directions allows gradient summation, resulting in stronger applied gradients and shorter TE values. Several studies have recently reported the value of measuring the diffusion coefficient to correlate with histologic findings of disease extent in prostate cancer (3)(4)(5)(6)(7)(8). These studies have reported the potential usefulness of diffusion weighted image (DWI) for detecting prostate cancer because it shows a lower apparent diffusion coef- Purpose: This study was performed to evaluate the usefulness of diffusion tensor imaging (DTI) and to correlate systemic twelve biopsy in prostate cancer.…”