ctabdo
Table of Contents
CT abdomen
Interpretation of the CT abdomen scan
basic concepts
- nearly all urologic calculi are radio-opaque on CT scan except for rare drug calculi (ciprofloxacin, indinavir, sulphonamides)
- differentiate ureteric calculi from phleboliths by evidence of surrounding inflammation around the ureteric calculus
- look for “dirty fat” (denser than normal fat) as evidence of localised inflammation
- hollow organs are just mucosal lining in a muscular tube - wall thickness and enhancement pattern are key to the diagnosis
- in suspected bowel obstruction look for:
- faeces sign as the location of obstruction
- evidence of perforation, abscess, fistula, ischaemia
- free fluid, mesenteric congestion, and absent mucosal enhancement are all signs of ischaemic gut
- caecal volvulus
- extreme dilatation of the cecum (with haustral creases in the upper left quadrant)
- fetal shape, faeces evident in descending colon on left abdomen
- whirl sign
- X-marks-the-spot sign,
- sigmoid volvulus
- large gas-filled loop without haustral markings, forming a closed-loop obstruction
- whirl sign: twisting of the mesentery and mesenteric vessels
- bird's beak sign: if rectal contrast has been administered
- X-marks-the-spot sign: crossing loops of bowel at the site of the transition
- Split wall sign: mesenteric fat seen indenting or invaginating the wall of the bowel
- signs of impending AAA rupture:
- large size > 7cm
- increasing size
- thrombus change - fissures, reduced size
- hyperattenuating crescent
- GIT bleeding:
- location found by carefully looking for gradual pooling on multiphase CT
- where is the fluid?
- fluid behind the liver represents pleural effusion or haemothorax
- fluid anterior to liver, in Morrison's pouch or in recto-vesical pouch/pouch of Douglas is intra-peritoneal
- fluid between pubic symphysis and bladder is extra-peritoneal
- fluid behind rectum is retroperitoneal
- intermesenteric fluid in abdominal trauma suggests mesenteric and/or bowel injury - look for triangular shapes!
splenic injury
American Assoc. for the Surgery of Trauma (AAST) grading
- grade 1
- subcapsular haematoma < 10% of surface area
- capsular laceration <1cm depth
- grade 2
- subcapsular haematoma 10-50% of surface area
- intraparenchymal haematoma < 5cm diameter
- laceration 1-3cm depth not involving trabecular vessels
- grade 3
- subcapsular haematoma >50% of surface area or expanding
- intraparenchymal haematoma > 5cm diameter or expanding
- laceration >3cm depth OR involving trabecular vessels
- ruptured subcapsular haematoma or intraparenchymal haematoma
- grade 4
- laceration involving segmental or hilar vessels with major devascularisation > 25% of spleen
- grade 5
- shattered spleen
- hilar vascular injury with devascularised spleen
Mx of blunt splenic injury
- urgent laparotomy if diffuse peritonitis or haemodynamically unstable
- angiography +/- embolisation if AAST grade IV or V with contrast blush, moderate haemoperitoneum or ongoing splenic bleeding
- consider embolisation for AAST grades III, IV or V
inflammatory conditions
- appendagitis
tumours
ctabdo.txt · Last modified: 2025/11/16 08:23 by gary1