My husband just had a ct scan that showed dilation in one of his kidneys. does this mean blockage?

Yes: A dilated ureter is the sign of blockage. This can be from anatomic problems, a kidney stone, enlarged prostate or anything pressing on or filing the inside of the tube leading away from the kidney. This needs evaluation by a urologist, the specialist best equipped to investigate this finding.

Hydronephrosis: Usually dilated kidney suggests a blockage, either partial or completely of that kidney. Often on a ct scan they can see if a stone was present or if there is inflammation suggesting a stone has passed.