Abdominal Imaging: Luminal organs Rowland Illing MA BMBCh DM FLS MRCS(Eng) FRCR
Aims Reference text & resources Management of a patient Imaging what and when to use What to ask and how to describe Segments of the digestive tract Normal imaging appearances Basic patterns of pathology Endoscopy vs radiology Selected pathology surgical sieve
E-book: http://oftankonyv.reak.bme.hu Also: www.radiopaedia.org
The art of medicine consists in amusing the patient while nature cures the disease Voltaire
Treat Diagnose Management of a Patient 1. Resuscitation 2. History 3. Examination 4. Simple investigation 5. Complex investigation 6. Treatment 7. Review/ Reassess/ Repeat
Complex (imaging) investigation Plain x-ray, inc. fluoroscopy Ultrasound CT MRI Conventional nuclear medicine PET Hybrid imaging +/- contrast
A note on GI contrast BARIUM Insoluble, excellent contrast IODINE (Gastrografin) Water soluble, suspected leak/perforation SINGLE CONTRAST Good for functional studies peristalsis Contours, stenosis, but may be fooled! DOUBLE CONTRAST Better specificity and sensitivity Barium coats mucosal surface, air dilates lumen
What to use? Expected to know the commonly used modalities ESR iguide
When to use Availability Cost Expertise Specific patient-related factors Traditional imaging hierarchy not necessarily best
What to ask before interpreting What is the question? What has been done before? (Hx, Ex, Simple Ix, Complex Ix, Treatment) Is there previous imaging? Is there previous imaging?
What to describe about an imaging exam What type of examination? Is it contrast enhanced? IV and/or Oral? What is the timing of enhancement? Orientation (CT/MR)/probe (US) What is being imaged? What is the significant finding? Relevant negatives What is the differential diagnosis (most likely first)
Luminal digestive tract Oropharynx Esophagus Stomach Duodenum Jejunum Ilium Colon Rectum Anal canal
Oropharynx Third part of the pharynx (Naso [above] & Hypo [below]) Soft palate to hyoid bone Key event swallowing Oropharyngeal motility study Fluoroscopic swallow of iodinated contrast Elderly with recurrent pneumonia/ post stroke/ H&N cancer?aspiration
Esophagus I Pharyngoesophageal junction (C5/6) to Gastroesophageal junction Peristalsis (5-9 seconds) Primary (vagus), secondary (intrinsic) & tertiary waves Aortic arch L main bronchus Contrast swallow. Single or double contrast As part of upper GI study Usually after normal, impossible or?perforated endoscopy Motility disorders & reflux
Esophagus II CT MRI Endoluminal US Local staging of esophageal cancer
Stomach Cardia, fundus, body, antrum, pylorus Esophagus Fundus Contrast swallow. Single or double contrast CO2 producing crystals As part of upper GI study Usually after normal, impossible or?perforated endoscopy Motility disorders & reflux active Ix! Pylorus Antrum Cardia Body CT for cancer staging
Duodenum Bulb, second, third & fourth parts 90% peptic ulcers in the bulb. Only portion intraperitoneal. Ampulla of Vater in second part Ligament of Treitz marks boundary with jejunum Blood supply celiac axis Endoscopy first Usually single contrast swallow after bariatric surgery?anastamotic leak CT or MR to stage cancer
Small bowel I Ligament of Treitz to ileocecal valve 7m long, left upper to right lower quadrant on 30cm mesenteric fan Mesentery blood vessels, fat, nerves & lymph nodes Classified as an organ in 2016 (Coffey & O Leary, Lancet Gast & Hepatol) Jejunum proximal 40%, Ilium distal 60% Jejunum thicker wall, wider lumen & more folds (Valvulae conniventes) Blood supply SMA Investigation of weight loss, abdominal pain (after large bowel pathology excluded) & follow up of surgery and IBD Strictures, ulcers and dysmotility
Small bowel II Single contrast follow through Positive contrast & CT Negative contrast & MR/CT Positive contrast & fluoroscopy Double contrast enteroclysis NJ tube, barium, methylcellulose chaser & fluoroscopy Capsule endoscopy US terminal ilium in IBD
Small bowel follow through
Large bowel I 1.5m Caecum; appendix; ascending, transverse, descending, sigmoid colon; rectum & anal canal Arterial supply from SMA (Jejunum to splenic flexure), IMA beyond Rectal bleeding, anaemia, abdominal pain, weight loss Colonoscopy first line unless acute
Large bowel II CT colonoscopy ( virtual colonoscopy ) Bowel preparation, muscle relaxant, air or CO2 insufflation via rectal tube Prone and supine CT series Reconstructed open or fly through
Large bowel III Double contrast barium enema Selected cases only, excellent mucosal detail Single contrast enema Postoperative, fistulas, level of obstruction, frail CT & MR for staging cancer or acute abdomen (CECT) US in?appendicitis
Basic patterns of pathology Patterns: Filling defect (in the lumen) Mural Extraluminal projections Compression Distension Narrowing
Filling defects Polyps Benign or malignant Sessile or pedunculated 1-2cm Masses More often malignant (adenocarcinoma below lower esophagus) >2cm Exophytic (into lumen) may bleed and obstruct early Intramural spread (infiltrate the wall) cause annular constriction
Intrinsic wall abnormality (mural) Fold thickening Inflammation Oedema Infiltration gastritis/ colitis heart failure, ischaemia lymphoma, linitis plastica
Extraluminal projections Ulcers mucosal defect Benign vs malignant Diverticula - mucosa intact True False All layers of bowel wall Mucosa only (colonic)
The role of plain film in abdominal imaging? I Erect CXR First line of investigation?perforation Position of the NGT
The role of plain film in abdominal imaging? II AXR May be helpful in?obstruction Mechanical obstruction vs ileus Level of pathology? But CECT best first line
Endoscopy vs Radiology Endoscopy Gastroenterologist / surgeon Directly visualize Biopsy Treat (inject/ stent) Invasive Risk Cost Radiology Radiologist No need for sedation Fewer complications Better at small bowel evaluation May need endoscopy
Select pathologies Diagnostic sieve congenital or acquired, benign or malignant Neoplastic/ Neurological Infective Inflammatory Degenerative Vascular Iatrogenic Metabolic Traumatic Immunological Ideopathic Apply to each section of the bowel
Pathology of the Esophagus Neoplastic SCC or adenocarcinoma Mass or stricture Congenital Atresia or TOF Paediatric Degenerative Achalasia Classic beaking Inflammatory Reflux Short stricture Traumatic Ingestion of acid Long stricture Neurological Dysmotility corkscrew esophagus Vascular Varicies Smooth indentations Degenerative Diverticula Classic pouching by anatomical region Zenker s - cricopharyngeal
Pathology of the Stomach Inflammatory Gastritis Erosions & thickening Inflammatory Peptic ulcer disease Ulcers Neoplastic Adenocarinoma Mass Iatrogenic Bariatric surgery Distorted anatomy
Small bowel Iatrogenic Adhesions Obstruction Inflammatory Crohns Ulcers & strictures Vascular Ischaemia from SMA Oedema, pneumatosis Infective TB Oedema, obstruction Neoplastic Lymphoma & adenoca Rare The string sign of Kantour Crohns stricture of the terminal ileum
Large bowel Neoplastic Adenoca Mass, obstruction Inflammatory UC Psudopolyps, ulcers Vascular Ischaemia from SMA/IMA Oedema Congenital Sigmoid volvulus Obstruction
Summary Read the book & browse the site Look at patients to see how they are managed (beyond Hx & Ex) Get the feel of what imaging to use and when to use it Remember what to ask and how to describe images Look at imaging every chance you have Start to distinguish normal from abnormal Recognize some common pathology Remember the diagnostic sieve it will save you!