Investigating Prostate Cancer Using QSM: Repeatability and Lesion Analysis

Motivation: Previous prostate QSM studies have investigated detection of intraprostatic calcifications but not subtle tissue susceptibility changes. Blood's susceptibility is directly proportional to its deoxygenation, and hypoxia is linked to aggressive phenotypes suggesting a hypothesis of increased susceptibility in cancerous lesions. Goal(s): To investigate whether cancerous lesions in the prostate show increased susceptibility. Approach: Using QSM reconstruction optimized for repeatability, susceptibility values were compared in cancerous lesions (19) v. non-cancerous MRI-negative regions (15) in 28 men undergoing prostate cancer screening. Results: QSM revealed large susceptibility differences in calcifications and haemorrhages. However, there was no statistically significant susceptibility difference between cancerous lesions and non-cancerous tissue. Impact: Using whole-prostate and two-pass masking greatly reduced streaks from large intraprostatic calcifications and haemorrhages. Although no significant susceptibility increases were observed in cancerous lesions, this repeatable, optimized high-resolution QSM pipeline will be applied to more subjects to improve statistical power.