1272 - Non-Contrast Perfusion Imaging of the Prostate using Dual-Module Velocity-Selective Arterial Spin Labeling MRI

10:55am - 11:00am ET

Room 160

Presenter(s)

Kun Qing, PhD - City of Hope Comprehensive Cancer Center, Duarte, CA

P. Wang¹, Y. Jiang², Z. Huang³, Y. R. Li⁴, K. Qing³, and J. Guo⁵; ¹City of hope, Duarte, CA, ²University of Michigan, Ann Arbor, MI, ³Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA, ⁴City of Hope, Duarte, CA, ⁵University of California, Riverside, Riverside, CA

Purpose/Objective(s): Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is part of routine multiparametric MRI (mp-MRI) for standard-of care prostate imaging. However, there exist numerous health issues associated with retention of gadolinium-based contrast agents in the brain, bone, skin, etc. It is also relatively difficult to quantify the DCE-MRI due to inconsistencies in imaging protocol and control over contrast injection. In this study, we propose a new non-contrast MRI perfusion imaging method using dual-module velocity-selective arterial spin labeling (ASL) technique designed for prostate imaging.

Materials/Methods:

A total of 10 healthy volunteers (65.3 ± 4.2 yrs) underwent MRI scans including ASL and T₂-weighted MRI. For each subject, the prostate volume was segmented (contoured) to delineate the central gland and peripheral zone on the T₂-weighted MRI and transferred to the ASL images through image fusion. Both the contouring and image fusion were confirmed by a physician and a medical physicist. The parameters of the ASL sequence included resolution: 3.1x3.1x4.0 mm; field of view: 20x20x6.4cm; acquisition time: 7-14 minutes.

To minimize motion artifact, the raw ASL time series were first motion-corrected using the functional MRI of Brain Software Library (Oxford University, UK) toolbox. The perfusion-weighted ASL images were then generated by pairwise subtraction. The repeatability of ASL was evaluated in a second visit, approximately one week apart, to test the inter-session reproducibility in a subset of the volunteers (n=7, 3 subjects dropped out).

Results: The mean ± standard deviation (M±std) values of the blood flow measured in the central gland and peripheral zone of the 10 volunteers are 14.4 ± 6.3 ml/100g/min and 14.0 ± 4.5 ml/100g/min respectively. There is no significant difference seen in the blood flow between the central gland and the peripheral zone in these 10 subjects. The differences of the blood flow measured between the two visits are1.8 ± 8.6 ml/100g/min and 4.7±4.4 ml/100g/min for the central gland and peripheral zone, respectively.

Conclusion: A new 3D non-contrast perfusion MRI method is implemented for applications in the prostate. Absolute blood flow values can be quantified in both central gland and the peripheral zone and are consistent with existing literature values. For example, Inaba T, J Urol showed that the prostatic blood flow was 15.7±7.5ml/100g/min by using ¹⁵oxygen-water by positron emission tomography. The measurement is repeatable. This method will be applied to identify prostate lesions and monitor changes in the prostate following radiation therapy in the ongoing study.