Preparation:

a) A liquid diet, avoiding carbonated beverages and gas-producing foods on the day before the procedure.

b) Bowel preparation (not mandatory): Purchase one (1) Fleet enemas from the Pharmacy (the Fleets are over the counter). Before your ultrasound test, administer one small Fleet enema at home on the morning of your exam. In most cases of mild disease, a small enema can be safely administered to improve imaging conditions for TPUS. However, in the presence of moderate or severe inflammation, strictures, significant anorectal complications, or ongoing acute bleeding, an enema may pose additional risks. Clinical judgment, based on the severity of the patient’s rectal disease and symptoms, is essential when deciding whether to use an enema before TPUS. "Please consult with your healthcare provider before using an enema, especially if you have active rectal inflammation, severe pain, bleeding, or known anorectal complications." 

Administering a small-volume enema before transperineal ultrasound (TPUS) can be beneficial. Here’s why:

1. Clearer Visualization:
   Residual fecal material in the rectum can impede ultrasound beam transmission and create acoustic shadows, making it harder to discern the distinct layers of the rectal wall. A gentle enema helps clear out this material, allowing more direct contact between the ultrasound probe and the rectal wall for better image quality.

2. Improved Layer Differentiation:
   Without interfering stool, the mucosal and submucosal layers, as well as their echogenicity and stratification, can be seen more clearly. This in turn leads to more accurate measurement of bowel wall thickness and a more precise assessment of vascular patterns.

3. Enhanced Visualization of Perirectal Structures:
   Clearing the rectal lumen enhances the ability to detect perirectal fat changes, fistulous tracts, small abscesses, or subtle inflammatory changes around the anal canal and sphincter complexes.

4. Patient Comfort and Compliance:
   A small-volume enema is generally well tolerated. Improved imaging quality can reduce the need for repeated examinations, thus improving overall patient comfort and workflow efficiency.

Practical Considerations:

The enema should be administered  before the examination to ensure the rectum is as clear as possible. Care should be taken to use a gentle solution and a small volume to avoid patient discomfort or significant distension.

Note: A fleet enema is a bottle with 133 ml of liquid in it.  It has a nozzle that is covered with gel. Apply it while lying on your side, inserting the nozzle into the anus and squirting the full content of the bottle into the rectum.  An urge to go to the toilet will follow the application.  Try to wait for 3 to 5 minutes before going to the toilet. After this, your rectum should be completely empty optimizing ultrasound images.