Meredith Sadinski BA, Presenter: Nothing to Disclose

Gregory Stanislaus Karczmar PhD, Abstract Co-Author: Nothing to Disclose

Yahui Peng PhD, Abstract Co-Author: Nothing to Disclose

Milica Medved PhD, Abstract Co-Author: Nothing to Disclose

Shiyang Wang PhD, Abstract Co-Author: Grant, Koninklijke Philips NV

Aytekin Oto MD, Abstract Co-Author: Research Grant, Koninklijke Philips NV Consultant, Guerbet SA

To investigate the role of a novel, hybrid T2-diffusion-weighted (DW) MR imaging sequence for diagnosis of prostate cancer and differentiation between aggressive and non-aggressive prostate cancers. This sequence exploits the dependence of ADC values on TE, and dependence of T2 relaxation time on b values and has the potential to improve registration between T2 and DW-MR images. 

22 patients with prostate cancer underwent pre-operative prostate MR including a hybrid imaging sequence; DW-MR images were acquired with up to 4 b-values between 0 and 750 s/mm² and TE’s between 47 and 200 ms, resulting in a 2x3 to 4x5 data array associated with each voxel. The voxel-based ADC and T₂ decay constants were calculated using a least squares fit at each TE and b-value, respectively. ROIs of cancer and normal tissue were delineated by a radiologist and pathologist based on correlation with histopathology of the prostatectomy specimen. The behavior of ADC and T2 with changing TE and b-value for normal and cancer voxels was evaluated by comparing the number of voxels within a single ROI which display increased T2 with increasing b value and decreased ADC with increasing TE. The Spearman rank-order test was used to evaluate correlation of this MRI parameter with Gleason score (GS) and Student’s t test for the difference between cancer and normal ROIs.

A significantly higher percentage of voxels in cancer ROIs (n=41) demonstrated increased T2 and decreased ADC values with increasing b and TE compared to normal ROIs (n=21) (mean 18.9% vs. 3.0%, p=0.00035). This percentage increased as GS increased (mean 9.5% for GS 6, 22.6% for GS 7, and 30.0% for GS 8 and 9 ROIs); this was a statistically significant trend with Spearman coefficient ρ=0.508 (p=2.5x10-5). 

Hybrid T2-DW- MR imaging shows promise for detection of prostate cancer and determination of its aggressiveness. Likely due to smaller glandular lumen volume, restricted diffusion, and high intracellular T2 in cancer cells, an increased number of voxels in prostate cancer ROIs demonstrate increased T2 and decreased ADC values with increased b and TE values. 

In addition to combining the already proven useful information from T2 and DW-MR images, Hybrid T2-DW-MR imaging can provide added quantitative parameters helpful for diagnosis of prostate cancer. 

Sadinski, M, Karczmar, G, Peng, Y, Medved, M, Wang, S, Oto, A, Evaluation of a Novel Combined T2-weighted and Diffusion-weighted MR Imaging Sequence for Diagnosis of Prostate Cancer and Determination of Its Aggressiveness: Correlation with Histopathology Following Prostatectomy.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14008050.html