pelviectasia means abnormally dilated(enlarged) pelvic portion of the kidney
.This needs to be differentiated from hydronephrosis
which is also a dilatation of pelvis as well as the collecting system of the kidneys and occurs due to some kind of obstruction to the flow of urine.
A mild ectasia on ultrasound
can be a subjective finding also and hence i recommend you to discuss the report with a urologist
and get further evaluated accordingly.
all the best