GFR of 50 to 60 is safe enough for MRI contrast exposure. As it is, the contrast used in MRI only rarely causes kidney
damage. What it more commonly does is, damage the skeletal muscles, that too, when GFR is below 30.
Yes, IgA Nephropathy
is a possibility. Only Kidney Biopsy
can conclusively prove it. Ask your Nephrologist
if he/she feels whether the biopsy is required.
You should be aiming at strict BP control, avoidance of pain killers and avoidance of alternative meds. Increase in proteins in urine and increase in serum creatinine
are markers of a worsening disease and in some cases, need for change in treatment approach.