CT of the abdomen and pelvis

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Author: Mikael Häggström [notes 1]



CT of the abdomen and pelvisX-ray of the abdomen and pelvisUltrasonography of the abdomen and pelvisAdrenal glandsLiverUltrasonography of the spleenSpleenBiliary tractPancreasKidneyCT of the urinary systemUltrasonography of the urinary systemAortaVertebral columnStomach and intestinesUrinary systemUrinary systemScrotal ultrasonographyMale reproductive systemFemale reproductive systemAbdomen and pelvis for menu.png
About this image

Basic screening

Compare with any previous exam.

Example approach:

Liver, spleen, adrenals and kidneys

Scan through the entire volumes and look mainly for focal changes.

  • The thickness of the adrenal glands is normally up to 1.0 cm.[1]

Further information:

  • Look at the gallbladder and biliary tract for visible stones or dilatation.
  • Also exclude hydronephrosis of the kidneys.

Free gas

Switch to a lung window (wide attenuation range), with main focus on the anterior wall, where gas most likely appears.
While in this window, also have a glance at the bases of the lungs for pleural fluid or obvious lung tumors.

Free fluid

Look mainly in the hepatorenal recess and inferiorly in the pelvis.

Lymph nodes

Look mainly around the aorta and iliac arteries.

Upper abdominal lymph node cutoffs
Retrocrural space 6 mm[2]
Paracardiac 8 mm[2]
Gastrohepatic ligament 8 mm[2]
Upper paraaortic region 9 mm[2]
Portacaval space 10 mm[2]
Porta hepatis 7 mm[2]
Lower paraaortic region 11 mm[2]

Small intestine

On CT scans, a small intestinal diameter of over 2.5 cm is considered abnormally dilated.[3][4][5]

Large intestine

Average inner diameters and ranges of different sections of the large intestine.[6]
  • Exclude dilatations.
  • Check the intestinal wall for any thickening of over 5 mm.[7] Focal, irregular and asymmetrical gastrointestinal wall thickening suggests a malignancy.[7] Segmental or diffuse gastrointestinal wall thickening is most often due to ischemic, inflammatory or infectious disease.[7]


  • Exclude aneurysm, which is generally defined as over 3 cm.[8]
Further information: CT of abdominal aneurysm

Urinary bladder

Quick look for obvious wall thickening.

Reproductive system

Males: Quick look at the prostate for obvious irregularities.

Females: Look mainly at the locations of the ovaries for any expansions.


Any signs of damage.

Other extra-peritoneal volumes

Quick overview to exclude mainly obvious soft tissue expansions such as hematomas (see CT of muscular hematoma).


Example report in a normal abdomen:

No free gas or ascites
No focal changes in parenchymatous organs
No hydronephrosis or dilated biliary tract
No pleural fluid in visualized thorax.
No enlarged lymph nodes.
Normal intestinal calibers.

This example is Public Domain, and can be copied without any need for author attribution.
See also: General notes on reporting

Special cases


  1. For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Radlines:Authorship for details.


  1. Antonio Carlos A. Westphalen and Bonnie N. Joe (2006). "CT and MRI of Adrenal Masses ". Appl Radiol 35 (8): 10–26. Archived from the original. . 
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Dorfman, R E; Alpern, M B; Gross, B H; Sandler, M A (1991). "Upper abdominal lymph nodes: criteria for normal size determined with CT. ". Radiology 180 (2): 319–322. doi:10.1148/radiology.180.2.2068292. ISSN 0033-8419. 
  3. Ali Nawaz Khan (2016-09-22). Small-Bowel Obstruction Imaging. Medscape. Retrieved on 2017-02-07.
  4. . Abdominal X-ray - Abnormal bowel gas pattern. radiologymasterclass.co.uk. Retrieved on 2017-02-07.
  5. Gazelle, G S; Goldberg, M A; Wittenberg, J; Halpern, E F; Pinkney, L; Mueller, P R (1994). "Efficacy of CT in distinguishing small-bowel obstruction from other causes of small-bowel dilatation. ". American Journal of Roentgenology 162 (1): 43–47. doi:10.2214/ajr.162.1.8273687. ISSN 0361-803X. 
  6. "Deficient Pms2, ERCC1, Ku86, CcOI in field defects during progression to colon cancer ". J Vis Exp (41). 2010. doi:10.3791/1931. PMID 20689513. 
  7. 7.0 7.1 7.2 Fernandes, Teresa; Oliveira, Maria I.; Castro, Ricardo; Araújo, Bruno; Viamonte, Bárbara; Cunha, Rui (2014). "Bowel wall thickening at CT: simplifying the diagnosis ". Insights into Imaging 5 (2): 195–208. doi:10.1007/s13244-013-0308-y. ISSN 1869-4101. 
  8. "ACC/AHA Guidelines for the Management of Patients with Peripheral Arterial Disease (lower extremity, renal, mesenteric, and abdominal aortic): a collaborative report from the American Associations for Vascular Surgery/Society for Vascular Surgery, Society for Cardiovascular Angiography and Interventions, Society for Vascular Medicine and Biology, Society of Interventional Radiology, and the ACC/AHA Task Force on Practice Guidelines (writing committee to develop guidelines for the management of patients with peripheral arterial disease)—summary of recommendations ". J Vasc Interv Radiol 17 (9): 1383–97; quiz 1398. September 2006. doi:10.1097/01.RVI.0000240426.53079.46. PMID 16990459.