(Learning as I paste and type).
"The peripheral zone is a thin layer of homogeneous high signal intensity with a hypointense, well-defined and non-interrupted capsula. The transition zone typically shows heterogeneity of intermediate signal intensities focally replaced by well-circumscribed hyperplastic nodules of BPH."
Most cancers form in the peripheral layer, which, I'm learning, usually has a homogeneous signal in an MRI. So the heterogeneous signal noted may correspond to the "focal lesions" including the G6 (3+3) seen in the biopsy, which, being at the apex, would mean it's in the periphery, I believe.
If you're going to have prostate cancer, the way to go is a single G6 lesions that cries out active surveillance! In any case, ask your uro about
this and any other concerns at your next visit -- uros are familiar with MRI interpretation, and, obviously, I am not
in any case, when reading imaging reports, I focus on the Findings and especially the Impressions sections.