I had a ct scan to look for thickening of the wall of my colon. scan showed no thickening but a contracted gallbladder after fasting. what's the tx?

Unless you have : Symptoms suggesting gallbladder disease i would do nothing. The gallbladder can contract by just drinking some water so a contracted one alone is of doubtful significance. Ultrasound can be used to look for gallstones should there be some need for further evaluation and hepatobiliary scans can look for abnormal gallbladder filling and emptying in patients with suspected gallbladder dysfunction.

None: The gallbladder was contracted because you were fasting. That's a normal response.