Assessment of Apparent Diffusion Coefficient Values as Predictor of Aggressiveness in Peripheral Zone Prostate Cancer: Comparison with Gleason Score

Abstract

Purpose. To determine association between apparent diffusion coefficient value on diffusion-weighted imaging and Gleason score in patients with prostate cancer. Methods. This retrospective case series was conducted at Radiology Department of Aga Khan University between June 2009 and June 2011. 28 patients with biopsy-proven prostate cancer were included who underwent ultrasound guided sextant prostate biopsy and MRI. MRI images were analyzed on diagnostic console and regions of interest were drawn. Data were entered and analyzed on SPSS 20.0. ADC values were compared with Gleason score using one-way ANOVA test. Results. In 28 patients, 168 quadrants were biopsied and 106 quadrants were positive for malignancy. 89 lesions with proven malignancy showed diffusion restriction. The mean ADC value for disease with a Gleason score of 6 was 935 mm2/s (SD = 248.4 mm2/s); Gleason score of 7 was 837 mm2/s (SD = 208.5 mm2/s); Gleason score of 8 was 614 mm2/s (SD = 108 mm2/s); and Gleason score of 9 was 571 mm2/s (SD = 82 mm2/s). Inverse relationship was observed between Gleason score and mean ADC values. Conclusion. DWI and specifically quantitative ADC values may help differentiate between low-risk (Gleason score, 6), intermediate-risk (Gleason score, 7), and high-risk (Gleason score 8 and 9) prostate cancers, indirectly determining the aggressiveness of the disease.

Comparison of field-of-view (FOV) optimized and constrained undistorted single shot (FOCUS) with conventional DWI for the evaluation of prostate cancer

“…Indeed, it is believed that rFOV reduces the partial volume effect between tumors and normal tissue and that it reflects a more accurate ADC values [12,13,18]. Despite these differences, the mean ADC values of prostate cancer in our study were within the range of measurements in previous reports [6,13,24].…”

“…Diffusion-weighted imaging (DWI) is one of the essential techniques in mp-MRI [3,4]. Further, DWI enables measurement of the apparent diffusion coefficient (ADC), which can be used to predict Gleason score [5,6].…”

A model describing diffusion in prostate cancer

“…(No attempt was made to perform an exhaustive search and this does not represent a complete list of prostate diffusion studies.) In three studies, field strength was not reported and was assumed to be 3 Tesla (T) . Studies were divided into two categories according to the precision with which Gleason score was specified: …”

A literature review of the association between diffusion-weighted MRI derived apparent diffusion coefficient and tumour aggressiveness in pelvic cancer

“…DW-MRI has been implemented in the clinic to detect and stage the primary tumour [6] and ADC has been shown in an early study to be a marker of tumour aggressiveness [3]. Its ability to differentiate between high and low risk tumours ( Figure 3) has been subsequently corroborated by different groups [7], who have indicated the ability of ADC to differentiate Gleason score 8 and 9 from Gleason score 6 and 7 tumours (P < 0.001) [8].…”

“…First and foremost, there is inevitable reporting bias towards patients with relatively aggressive disease [6,10,11,14,15].…”