Abnormal Gas Distribution Pneumoperitoneum Definition Free intra-abdominal gas – it usually indicates perforation of a viscus (it is often a peptic ulcer – a perforated appendix rarely demonstrates free gas) ▪ Other causes: bowel obstruction ▸ appendicitis ▸ bowel ischaemia…
Benign Diseases Ascites Definition >100 ml of free fluid within the peritoneal cavity due to benign or malignant causes ▪ Transudative fluid: portal hypertension/cirrhosis/heart failure/nephrotic syndrome ▪ Exudative fluid: infection/peritoneal carcinomatosis ▪ Blood: trauma/tumour rupture/haemorrhagic diathesis ▪ Purulent fluid: intestinal perforation…
Miscellaneous Splenic Conditions Normal variants and congenital anomalies Splenunculus: this represents ectopic splenic tissue of congenital origin ▸ they can be single or multiple and are usually found at the splenic hilum ▸ they have similar imaging (and enhancement) appearances…
Congenital Abnormalities Embryology The pancreas develops in two parts from the endoderm of the primitive duodenum Dorsal part: this is the first part to appear, initially appearing as a diverticulum from the dorsal wall of the duodenum ▸ it forms…
Methods of Investigation Magnetic Resonance Cholangiopancreatography (MRCP) Technique Heavily T2-weighted coronal oblique fast spin-echo sequence to obtain source data (aligned along the plane of the common bile duct [CBD]) ▪ Stationary water appears as areas of high SI and adjacent…
Anatomy and Imaging Techniques Anatomy Couinaud classification The liver is subdivided anatomically into 8 segments; segments II – VIII are divided anatomically via the portal and hepatic veins The caudate lobe (segment I): this is autonomous, receiving vessels from both…
Ulcerative Colitis and Toxic Megacolon Ulcerative Colitis (UC) Definition A relapsing and remitting inflammatory bowel disease predominantly involving the colorectal mucosa and submucosa ▸ there is symmetrical colonic involvement (cf. asymmetrical Crohn's disease) It always involves the rectum – any…
Crohn's Disease (CD) Crohn's Disease Definition A chronic progressive transmural granulomatous inflammatory bowel disease There are typically discontinuous (‘skip’) lesions with asymmetrical bowel wall involvement It can affect any part of the GI tract – however it almost always affects…
Peptic Ulceration, Gastric Heterotopia, Duodenal Diverticula Peptic Ulceration Definition Mucosal ulceration occurring within an acidic part of the GI tract ▸ it is often associated with H. pylori infection ▸ duodenal ulcers are 2–3x more common than gastric ulcers ▪…
Benign Gastric Ulcers Benign Gastric Ulcers Definition Gastric ulcers penetrate the stomach wall through the mucosa and into the submucosa (and frequently also into the muscularis propria) ▸ 95% are benign and they can also be multiple Causes Helicobacter pylori…