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AN54.1-4 | Radiodiagnosis — Part 2

Barium Studies — GI Tract Imaging (AN54.3)

Barium and Contrast Studies

Study	Region Evaluated	Key Indications	Key Anatomical Findings
Barium swallow	Oesophagus	Dysphagia, stricture, achalasia	Four normal narrowings, mucosal folds
Barium meal	Stomach + duodenum	Peptic ulcer, gastric carcinoma	Rugae, pylorus, duodenal cap, ulcer niche
Barium enema	Large intestine	Colonic carcinoma, diverticulosis	Haustrations, flexures, apple core lesion
Cholecystography (OCG)	Gallbladder + cystic duct	Gallstones (largely replaced by USG)	Gallstone filling defects
IVP	Kidneys, ureters, bladder	Renal stones, ureteric obstruction	Three ureteric narrowings, hydronephrosis
Hysterosalpingography (HSG)	Uterine cavity + fallopian tubes	Infertility, tubal patency	Tubal blockage, uterine anomalies

Barium sulfate is swallowed or introduced rectally to coat the mucosal surface and reveal detail of the GI tract. Single-contrast (barium only) or double-contrast (barium + air insufflation — better mucosal detail).

Barium Studies — GI Tract Imaging (AN54.3) — Multi-panel illustration of barium and contrast studies: barium swallow with oesophageal narrowings, barium meal with duodenal ulcer, barium enema with apple core lesion, and IVP with ureteric narrowings

Barium and Contrast Studies of the GI and Urogenital Tracts

Study	Region Evaluated	Key Indications	Characteristic Findings
Barium Swallow	Pharynx, oesophagus, GOJ	Dysphagia, stricture, achalasia, hiatus hernia	Bird-beak (achalasia), rat-tail narrowing (carcinoma), mucosal irregularity
Barium Meal	Stomach, duodenum (D1-D3)	Peptic ulcer, gastric carcinoma, pyloric stenosis	Barium niche (ulcer crater), filling defect (tumour), string sign (pyloric stenosis)
Barium Enema	Large bowel (caecum to rectum)	Obstruction, diverticulosis, colorectal carcinoma, IBD	Apple-core lesion (carcinoma), lead-pipe colon (UC), cobblestoning (Crohn's)
Cholecystography (OCG)	Gallbladder and biliary tree	Gallstones, GB function	Filling defects (stones), non-visualisation (blocked cystic duct)
IVP (IV Urography)	Kidneys, ureters, bladder	Renal stones, hydronephrosis, ureteric obstruction	Delayed nephrogram, dilated calyces, filling defects in ureter/bladder
Hysterosalpingography (HSG)	Uterine cavity, fallopian tubes	Infertility, tubal patency, uterine anomalies	Tubal blockage, spillage (patent tubes), uterine filling defects

Barium Swallow:
Patient swallows barium under fluoroscopy. Evaluates: pharynx, oesophagus, gastro-oesophageal junction.
Indications: dysphagia, oesophageal stricture, achalasia, pharyngeal pouch, hiatus hernia, carcinoma of oesophagus.
Key findings: bird-beak appearance (achalasia), rat-tail narrowing (carcinoma), mucosal irregularity, reflux.

Barium Meal:
Evaluates stomach and duodenum (1st–3rd parts).
Key findings: Barium niche (ulcer crater), filling defect (tumour), deformity of duodenal cap (cloverleaf deformity in chronic duodenal ulcer disease), mucosal pattern.

Barium Enema:
Barium introduced per rectum. Evaluates colon (large intestine from rectum to caecum).
Double-contrast technique preferred for mucosal detail.
Key findings: apple-core (napkin-ring) lesion = colonic carcinoma; thumbprinting = ischaemic colitis or inflammatory bowel disease; diverticular disease (outpouchings); strictures.

Cholecystography (Oral Cholecystogram):
Oral contrast is absorbed from gut → excreted in bile → concentrates in gall bladder (if functioning). Now largely replaced by ultrasound. Still asked in exams.
Assesses: gall bladder function, radiolucent gallstones (filling defects).

Intravenous Pyelography (IVP / IVU):
IV iodinated contrast excreted by kidney → visualises pelvicalyceal system, ureter, urinary bladder.
Key images: nephrogram (parenchyma), pyelogram (collecting system), ureterogram, cystogram.
Key findings: hydronephrosis (delayed drainage, dilated pelvicalyceal system), filling defects (stone, tumour), ureteric deviation, bladder outline.
Now supplemented/replaced by CT KUB (CT urogram) for stone disease.

Hysterosalpingography (HSG):
Iodinated contrast injected through cervix → opacifies uterine cavity and fallopian tubes → spills into peritoneum if tubes are patent.
Indications: infertility workup (tubal patency assessment), intrauterine pathology (fibroids, polyps, septum), Asherman syndrome.
Key findings: tubal block (contrast doesn't spill), uterine filling defects, tubal hydrosalpinx.

SELF-CHECK

A barium meal examination shows a persistent outpouching (niche) in the duodenal cap with surrounding mucosal convergence. What is the most likely diagnosis?

A. Duodenal carcinoma

B. Duodenal ulcer

C. Crohn's disease of the duodenum

D. Hiatus hernia

Reveal Answer

Answer: B. Duodenal ulcer

A "niche" on barium meal (persistent crater that retains barium) with surrounding radiating mucosal folds is the classic appearance of a peptic ulcer — in the duodenum most commonly in the duodenal cap (bulb/1st part). Carcinoma would show irregular filling defect, not a niche. Hiatus hernia is a gastro-oesophageal junction finding.

ERCP, CT Abdomen, MRI, and Arteriography (AN54.4)

Advanced Abdominal Imaging

Modality	Technique	Primary Abdominal Uses
ERCP	Endoscopic cannulation of ampulla + contrast injection	CBD stones, biliary strictures, pancreatic duct pathology
CT abdomen	IV contrast + axial cross-sections	Acute abdomen, tumour staging, trauma, AAA
MRI/MRCP	Magnetic resonance, T2-weighted for MRCP	Liver lesions, biliary/pancreatic ducts, pelvic staging
CT angiography	IV contrast + 3D reconstruction	AAA, renal artery stenosis, mesenteric ischaemia
Arteriography (DSA)	Intra-arterial catheter + digital subtraction	GI bleeding localisation, hepatic embolisation

ERCP (Endoscopic Retrograde Cholangio-Pancreatography):
Combines endoscopy + fluoroscopy. Endoscope passed to second part of duodenum → cannulate the ampulla of Vater → inject contrast → outline biliary tree and pancreatic duct.
Diagnostic + therapeutic: remove CBD stones (sphincterotomy + stone extraction), place stents for biliary strictures, biopsy ampullary tumours.
Key findings: CBD stone (filling defect), biliary stricture, pancreatic duct dilation or stricture (chronic pancreatitis), cholangiocarcinoma.
Replaced diagnostically by MRCP (non-invasive) but ERCP remains gold standard for therapy.

ERCP, CT Abdomen, MRI, and Arteriography (AN54.4) — Multi-panel illustration of advanced imaging: ERCP with biliary cannulation and choledocholithiasis, contrast CT at L1 with pancreatic mass, MRCP showing biliary tree non-invasively, and CT angiography of the abdominal aorta

Advanced Abdominal Imaging — ERCP, CT, MRI, and Arteriography

Modality	Technique	Primary Abdominal Uses	Key Advantages
ERCP	Endoscopic retrograde injection of contrast into bile and pancreatic ducts	CBD stones, biliary stricture, pancreatic duct pathology	Diagnostic + therapeutic (sphincterotomy, stent, stone extraction)
CT Abdomen (multi-slice)	Rapid cross-sectional imaging; plain, arterial, portal venous phases	Acute abdomen, trauma, tumour staging, AAA, pancreatitis, IBD	Speed, wide availability, triple-phase liver characterisation (HCC, metastases, haemangioma)
CT KUB (non-contrast)	Unenhanced CT of kidneys, ureters, bladder	Urolithiasis (calculi > 2 mm)	High sensitivity for stones without contrast
MRI / MRCP	Magnetic resonance; MRCP = heavily T2-weighted for fluid-filled ducts	Liver lesions, biliary obstruction, pancreatic pathology, pelvic organs	No radiation, excellent soft-tissue and ductal anatomy
Arteriography (DSA)	Intra-arterial catheter with digital subtraction	Mesenteric ischaemia, GI bleed localisation, renal artery stenosis, pre-op vascular mapping	Gold standard vascular anatomy; can be therapeutic (embolisation)

CT Abdomen:
Multi-slice CT provides rapid imaging of all abdominal structures.
Uses in abdomen: acute abdomen (appendicitis, diverticulitis), trauma (solid organ injury, haemoperitoneum), tumour staging, AAA (abdominal aortic aneurysm), pancreatitis, inflammatory bowel disease.
CT KUB (non-contrast): stone disease — sensitive for calculi >2 mm.
Triple-phase CT liver: plain + arterial + portal venous phases — characterises hepatic lesions (HCC, metastases, haemangioma).

MRI Abdomen:
Superior soft tissue contrast, no radiation. Preferred for:
• MRCP — non-invasive biliary and pancreatic ductal imaging (replaced diagnostic ERCP)
• MRI liver — characterisation of liver lesions (diffusion, T1/T2 characteristics)
• MRI rectum — staging of rectal carcinoma (pre-operative planning — local invasion, lymph nodes)
• MRI pelvis — uterine/ovarian pathology, endometriosis, fistulae

Arteriography (DSA / CT Angiography):
• Coeliac axis angiography — maps hepatic, splenic, left gastric arteries; pre-operative vascular mapping; embolisation for haemorrhage
• Mesenteric angiography — acute GI bleed localisation; mesenteric ischaemia
• Renal arteriography — renal artery stenosis (renovascular hypertension); pre-embolisation for AVM
• Portal venography — portal hypertension assessment, TIPS procedure guidance
• CT angiography (CTA) is now often preferred over DSA for diagnosis.

SELF-CHECK

A 45-year-old woman with obstructive jaundice is evaluated for suspected CBD stones. Which investigation is MOST appropriate as the first non-invasive approach to image the biliary tree?

A. ERCP

B. MRCP

C. IVP

D. Barium meal

Reveal Answer

Answer: B. MRCP

MRCP (Magnetic Resonance Cholangiopancreatography) is the non-invasive gold standard for imaging the biliary tree and pancreatic duct. It has replaced diagnostic ERCP. ERCP is reserved for therapeutic purposes (stone removal, stent placement). IVP and barium meal do not visualise the biliary tree.

CLINICAL PEARL

Rigler's Sign vs. Gas under Diaphragm:
On a supine plain X-ray abdomen, free intraperitoneal air cannot rise above the diaphragm — it distributes around bowel loops. Rigler's sign (double-wall or bowel wall sign) is seen: gas on both sides of the bowel wall, making the wall visible as a thin line. On an erect film, gas collects under the diaphragm. In a patient who cannot stand, a left lateral decubitus film (patient lies on left side, X-ray taken horizontally) shows free air above the liver — a highly sensitive sign of perforation.

ALARA Principle (As Low As Reasonably Achievable):
Radiation from X-rays and CT carries a small cancer risk. In young patients and pregnant women, prefer ultrasound (no radiation) or MRI for non-urgent evaluation. CT is reserved for situations where speed and anatomical detail outweigh the radiation risk (trauma, acute abdomen).