JC Block C - Diagnostic Radiology - Gastrointestinal Flashcards
Advantages and Limitations of AXR for GI imaging
Compare small bowel and large bowel on AXR:
Placement Mucosa Content Caliber Bowel gas Fluid
Normal GIT structures with gas within
Stomach
2-3 loops of non-distended small bowel
Rectum and sigmoid colon
Describe picture
> 2-3 fluid levels in small bowel
DIlated small bowel >3.5cm
Indicates IO
Abnormality?
Dilated Large bowel >5cm
Large bowel IO
Abnormality?
Pneumoperitoneum:
Free gas under diaphragm
Rigler sign (can see both sides of the thin bowel wall clearly due to presence of intra- and extraluminal gas
Falciform ligament sign (aka Silver sign): falciform ligament outlined with free abdominal gas
Barium and contrast studies
Functions
Indications for different contrasts
Functions:
Coat and show bowel mucosa
Dynamic study (assess bowel motility)
Demonstrate obstruction and leaks
Indications:
Barium double contrast studies - better visualization of the mucosal pathology e.g. IBD
Water-soluble contrast for perforation/ anastomotic leak (c/i barium peritonitis)
4 types of barium studies
Indications for barium swallow
- Difficulty swallowing (dysphagia)
- Suspect tumors, strictures, ulcers, esophagitis (inflammation)
- Video fluroscopic swallowing exam - esophagus motility problems
Label
Label
Indications for barium meal
Indications:
Dyspepsia (indigestion)
Weight loss (?malignancy)
Upper abdominal mass
Iron deficiency anaemia (GI hemorrhage)
Partial upper GIT obstruction (e.g. gastric outlet obstruction)
Compare SB follow through and SB enema
Procedure
Contrast
Pro
Cons
Indications for barium enema
Alteration in bowel habit Chronic diarrhea/ constipation Rectal bleeding Abdominal pain Suspected abdominal mass Obstruction
Label
CT abdomen
Advantages
1) Fast imaging
2) Extra-colonic assessment E.g. colorectal cancer staging
3) Multi-planar reconstruction
4) Excellent anatomical correlation
Lesion
Colitis – ulcerative colitis
Marked thickening of mucosa,
reducing the normal haustra pattern
Lesion
Enteritis secondary to ischemia:
small bowel wall abnormally
thickened and enhancing
Lesion
Perforation: CT is sensitive for small pocket of gas in intraperitoneal cavity
Lesion
Distended small bowel loops
Small bowel obstruction
Lesion
Large bowel obstruction
Distended and filled with fecal
material
Signs and causes of SB obstruction
Indications for GIT angiogram
Modalities
Acute/ chronic ischemia
Aneurysm
Crohn’s disease
Gastrointestinal bleeding
Mesenteric CT angiogram
Angiography (allows intervention e.g. trans-arterial embolization)
Indication of USG for GIT exam
Lack of radiation useful in paediatric group
Selected conditions:
Appendicitis
Intussusception
Pelvic abscess from bowel perforation
Indications for MRI and PET/CT scans for GIT
MRI:
Cancer staging and treatment strategy
MR Enterography - for strictures and inflammatory enhancement
PET/CT:
Cancer staging, chemo treatment response
Case 1: F/75 Presented with weight loss and dysphagia Refused endoscopy FBC shows microcytic anaemia
Imaging? Features?
Barium swallow:
Stricturing at distal esophagus before coming into stomach
Features suggesting a malignant stricture:
Irregular outline
‘Shouldering’ sign
Proximal dilatation of esophagus
should be followed up with endoscopy
DDx: achalasia (smooth tapering of distal esophagus)
Role of imaging in oesophageal cancer:
Staging
Treatment planning (e.g. whether undergo upfront surgery or preoperative chemoirradiation)
Surgical planning
Follow-up/ assessment of treatment response (chemotherapy)
Case 2: M/65 Fresh PR bleeding and weight loss FBC shows microcytic anaemia Could not tolerate endoscopy (colonoscopy)
Imaging and features
Barium enema (double contrast – barium and air): Short segment of irregular stricturing - apple core appearance
Follow up with CT e.g. CT colonography (CTC), Staging with MRI
colorectal cancer
Role of imaging in colorectal cancer
Screening (e.g. CT colonography (CTC)
Staging (e.g. MRI)
Treatment planning/ stratification
Surgical planning
Follow-up/ assessment of treatment response
Case 3: F/75 presented to A&E Confused Poor historian Intermittent abdominal distension and pain
Imaging and feature?
AXR:
Distended bowel loop in mid abdomen obstruction and dilatation
Dx: sigmoid volvulus
Imaging features of sigmoid vs cecal volvulus
Case 4:
M/80
Presented with 4 days history abdominal pain and distention
PHx appendicitis. Nil else
Imaging and finding?
AXR:
Multiple loops of distended small bowel
Paucity of large bowel
Multiple air-fluid levels (arrows)
On the left, bowel gas extends beyond pelvic ring (important to include this area in radiology)
Small bowel obstruction due to strangulated inguinal hernia
Case 5: F/32 banker presented to A&E No PHx Sudden onset severe abdominal pain On examination: perintonitic
Imaging and Feature
AXR: pneumoperitoneum (recall falciform ligament sign, Rigler sign)
Suspect perforation follow up with water-
soluble contrast upper GI study:
Case 6:
M/30
Previously fit and well
A few days history of low grade fever and vague abdominal pain
Presented with A&E with localised severe right iliac fossa pain
CT abdomen and pelvis: Appendicolith: calculus obstructing appendiceal orifice distal obstruction and dilatation of appendix Right para-colic gutter collection Dx: appendicitis
Case 7:
F/34 British
Presented to A&E with bloody diarrhoea and fever (acute on chronic presentation)
Intermittent diarrhoea and abdominal pain for a year
Known history of UC
Imaging and feature
AXR on admission:
Grossly distended and featureless colon (esp transverse, descending and sigmoid)
Toxic megacolon (at risk of perforation)
