Water and abdominal ultrasound preparation

Some scans require a comfortably full bladder because fluid creates a clearer viewing window for structures in the lower abdomen and pelvis. Other abdominal scans focus on organs such as the liver or gallbladder and may instead require fasting. Your appointment instructions should say whether to drink water, how much to drink, and whether to avoid emptying your bladder.

Ultrasound uses sound waves to form images. Air in the bowel can interrupt those waves, while fluid in the bladder can help the sonographer see nearby tissues more clearly. Drinking water does not improve every type of abdominal image, which is why generic preparation advice may conflict with the instructions for your particular examination.

A full bladder is a preparation aid, not a treatment and not a sign that anything abnormal has been found. The sonographer may ask you to empty your bladder partway through if another view is needed.

Check the written appointment message rather than relying on advice for a different ultrasound. If water is required, drink it during the period specified and keep your bladder full unless staff tell you otherwise. Take regular medicines with a small amount of water unless your clinician has provided different instructions.

Contact the imaging centre before arrival if fluid restriction, kidney or heart problems, pregnancy-related nausea, diabetes, or bladder symptoms make the instructions difficult. If you accidentally urinate, cannot finish the water, or ate when fasting was requested, tell the team; they can decide whether useful images are still possible.

Preparation discomfort should ease after you are allowed to empty your bladder. Seek prompt medical assessment for severe or rapidly worsening abdominal pain, a rigid or markedly swollen abdomen, repeated vomiting, fainting, blood in vomit or stool, yellowing of the eyes or skin, or inability to pass urine. Do not keep drinking water to prepare for a scan if it is causing significant distress; call the imaging centre for instructions.

Confirm which area will be examined, whether you need a full bladder or fasting, and whether your medicines can be taken normally. You can also ask what to do if you cannot tolerate the requested water and when the report will be sent to the clinician who ordered the scan.