Ssames, I can understand your concern. I found this study comparing the MRI with and without contrast.

- Comparison between multiparametric MRI with and without post - contrast sequences for clinically significant prostate cancer detection https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6442176/

The researchers found that exams with and without contrast were similar for detection of clinically significant prostate cancer on MRI.

The study found similar results
- Is contrast enhancement needed for diagnostic prostate MRI? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5503975/
"gadolinium-based contrast agent seems not to be strictly necessary in the detection and localization of prostate cancer."

Also keep in mind that your husband's doctor's use multi diagnostic tools to inform them about the diagnosis and treatment plan. Did you share your concerns with your husband's oncologist? Did your husband get a diagnosis of prostate cancer?