What is a filling cystometrogram (CMG)?

Updated: Dec 24, 2020
  • Author: Bradley C Gill, MD, MS; Chief Editor: Edward David Kim, MD, FACS  more...
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A filling cystometrogram (CMG) assesses the bladder capacity, compliance, and the presence of phasic contractions (detrusor instability). Most commonly, liquid filling medium is used.

An average adult bladder holds approximately 50-500 mL of urine. During the test, provocative maneuvers help to unveil bladder instability.

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