Condition Specific Radiology: Ascites

OVERVIEW

This page is dedicated to covering how the condition ascites will appear on different types of radiological imaging studies.

Ascites refers to fluid that has collected in the peritoneal cavity (image source)
BASIC CHARACTERISTICS

The following are characteristic of ascites that inform its interpretation across imagine modalities:

  • Density/properties similar to water: the appearance of ascites on imaging modalities is reflected by its density/properties that are similar to water.
    • Exudative ascites may in some cases be more dense then water !
  • Gravity dependent: given that ascites is free fluid in the peritoneal space, its location is gravity dependent.
ABDOMINAL ULTRASOUND

Key features of ascites seen in this imaging modality are:

  • Anechoic nature: ascites will allow sound waves to pass through it, so it will appear black/dark on ultrasound.

The gallery below organizes examples of how ascites will appear on abdominal ultrasound. Click on the thumbnails below to open up the gallery:

ABDOMINAL COLOR DOPPLER ULTRASOUND

Key features of ascites seen in this imaging modality are:

  • Anechoic nature: ascites will allow sound waves to pass through it, so it will appear black/dark on ultrasound.
  • Absence of color doppler signal: there should be no flow signal seen throughout the ascites. Ascites should not move around if the patient is still, and it should not contain vessels.

The gallery below organizes examples of how ascites will appear on abdominal color doppler ultrasound. Click on the thumbnails below to open up the gallery:

ABDOMINAL/PELVIC CT-SCAN WITHOUT IV OR ORAL CONTRAST

Key features of ascites seen in this imaging modality are:

  • Density similar to water (transudative ascites): typically between -10 and + 10 HU
  • Density slightly above water (exudative ascites): can be above 15 HU

The gallery below organizes examples of how ascites will appear on a abdominal/pelvic CT-scan without the usage of either IV or oral contrast. Click on the thumbnails below to open up the gallery:

ABDOMINAL/PELVIC CT-SCAN WITH ONLY ORAL CONTRAST

Key features of ascites seen in this imaging modality are:

  • Density similar to water (transudative ascites): typically between -10 and + 10 HU
  • Density slightly above water (exudative ascites): can be above 15 HU
  • Does not enhance with oral contrast: typically this should not occur (unless there is bowel perforation/connection/fistula to the GI tract and the peritoneum).

The gallery below organizes examples of how ascites will appear on a abdominal/pelvic CT-scan with the usage of only oral contrast. Click on the thumbnails below to open up the gallery:

ABDOMINAL/PELVIC CT-SCAN WITH ONLY IV CONTRAST

Key features of ascites seen in this imaging modality are:

  • Density similar to water (transudative ascites): typically between -10 and + 10 HU
  • Density slightly above water (exudative ascites): can be above 15 HU
  • Does not enhance with IV contrast: typically this should not occur, however delayed enhancement of ascites can occur in some cases. Perfused organs should appear significantly brighter then surrounding ascites.

The gallery below organizes examples of how ascites will appear on a abdominal/pelvic CT-scan with the usage of only IV contrast. Click on the thumbnails below to open up the gallery:

ABDOMINAL/PELVIC CT-SCAN WITH IV & ORAL CONTRAST
  • Density similar to water (transudative ascites): typically between -10 and + 10 HU
  • Does not enhance with oral contrast: typically this should not occur (unless there is bowel perforation/connection/fistula to the GI tract and the peritoneum).
  • Density slightly above water (exudative ascites): can be above 15 HU
  • Does not enhance with IV contrast: typically this should not occur, however delayed enhancement of ascites can occur in some cases. Perfused organs should appear significantly brighter then surrounding ascites.

The gallery below organizes examples of how ascites will appear on a abdominal/pelvic CT-scan with the usage of both IV and oral contrast. Click on the thumbnails below to open up the gallery:

 

 

Page Updated: 06.20.2017