dr. kawa bilateral

Radiology

GASTROINTESTINAL SYSTEM

By: Dr. Kawa Typed by: Bnar J. Ahmed Paywand M. Ali Rako Abdulqadir Ranko B. Majeed Suren Y. Hama Baqi

Design: Rzgartmi.

CONTENTS CONTENTS 2 RA

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CONTENTS CONTENTS

CONTENTS 2

ESOPHAGUS 3 Normal barium swallow 3

Abnormal barium swallow: 3 • Stricture: 3 • Filling defect 4 • Dilatation of esophagus 5 • Varices 5 • Esophagus web 5 • Diverticula 5 • Esophageal atresia 5 • Candidiasis 5

STOMACH AND DUODENUM 6 Normal barium meal: 6

Gastroscopy: 6 • Indications: 6

Abnormal barium meal findings 6 • Filling defects (intarluminal,

intramural, extramural) 7 • GU 7 • narrowing 8 • Thick gastric mucosal folds 8 • Gastric outlet obstruction 8 • Gastritis 9 • Hiatus hernia 9 • DU 9

Upper GI bleeding: 9

SMALL INTESTINE 9 Normal Ba follow through: 10

Enteroclysis: 10

Abnormal Ba follow through: 10

Crohn’s disease: 10

Tb: 11

Lymphoma: 11

Malabsorption: 11

• Definite Dx 11 • Signs: 11

Disaccharidase deficiency: 11

Acute SI obstruction: 12

LARGE INTESTINE 12 Indications for colonoscopy: 12

Normal Ba enema: 12

Abnormal Ba enema: 12 • Narrowing of the lumen: 12 • Dilatation of colon: 13 • Filling defects in the colon: 13 • Ulceration of colon: 13

Tumors of the colon: 14 • Polyp 14 • Carcinoma 14

Hirschsprung’s disease 15

Idiopathic megacolon 15

Acute Bleeding (S and L bowel) 15

HEPATOBILIARY SYSTEM 15 Methods of imaging: 15

Normal liver: 15

Liver masses: 16 • Masses include the following:

16 Liver trauma: 17

Liver cirrhosis and portal hypertension: 17

Fatty degeneration of the liver: 18

Biliary system 18 • Ultrasound 18 • CT 18 • Radionuclide scan: 18 • ERCP: 19 • Others 19

Gall stones and chronic cholecystitis 19 • Plain film: 19 • U/S: 19

Acute cholecysitis 20 • U/S: 20

Jaundice: 20 • US shows: 20 • CT-scan: 20 • Others 21

SPLEEN AND PANCREAS 21 Spleen: 21

Pancreas: 21 • Pancreatic masses: 21 • Adenocarcinoma of pancreas

21 • Acute pancreatitis 22 • Chronic Pancreatitis 22 • Pancreatic trauma 22

PERITONEAL CAVITY AND RETROPERITONEUM 23 Peritoneal cavity 23 • Ascites 23 • Peritoneal tumors 23 • Intra peritoneal abscess 23

Retroperitoneum 24 • Retroperitoneal organs: 25 • Retroperitoneal

Lymphadenopathy 25 • Adrenal glands 25 • Retroperitoneal tumor 27 • Aortic aneurism 27 • Retroperitoneal hematoma 27 • Retroperitoneal abscess and

psoas abscess 27

ALL THE POST MIDYEAR| 2010 3

GASTROINTESTINAL SYSTEM| DR. KAWA

ESOPHAGUS Plain film very dilated- opaque FB Barium swallow is the contrast examination to visualize the esophagus Oblique view to project the esophagus clear of the spine. Take films under fluoroscopy ... full of barium to show outline. Empty of barium to show the mucosal pattern.

Normal barium swallow

1- Full of barium smooth outline 2- Empty of barium folds of mucosa( three or four long straight parallel lines) 3- Impressions

Aortic arch impression on the Lt side of the esophagus Lt main bronchus smaller impression below the esophagus

4- Peristaltic waves can be observed during fluoroscopy contraction wave peristalsis

Undulated appear as tertiary contraction Normal in elderly Diffuse esophageal spasm if associated with dysphagia

Abnormal barium swallow:

look for: Stricture, filling defect, dilatation, varices, esophageal web , diverticula, esophageal atresia, candidiasis.

Stricture: is an important cause of dysphagia. Causes: CA, peptic stricture, achalasia and corrosive stricture Distinction between these depends on site, shape, length, soft tissue mass.

CA Usually involves a full circumference to form stricture and rarely arises from only one wall. As a rule: CA esophagus usually presents as a stricture and not as a filling defect or mass.

Abnormal barium swallow: ESOPHAGUS 4 RA

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URadiological feature - Full circumference - Irregular lumen - Shouldering edges - Several CMs in length - Soft tissue mass may be visible

CT preoperatively shows tumor, invasion, LN involvement and metastasis

Peptic stricture - Lower end of the esophagus - Almost invariably associated with hiatus hernia and GERD - Characteristically short - Smooth outlines - Tapering ends - Ulcer may be seen nearly

Achalasia : Is a failure of relaxation of LES URadiological feature

Smooth, tapering narrowing, always at the lower end of esophagus, dilatation of esophagus above it, absent peristalsis, food residues are present, consolidation and bronchiectasis in the lung, absent stomach gas bubble(usually), but not diagnostic

Corrosive stricture Long stricture, smooth, tapering ends, may be irregular

Filling defect (Intraluminal, intramural, extramural) - Intraluminal usually food lump, look for associated stricture - Intramural usually leiomyoma Smooth, Rounded indentation But CA (irregular filling defect, usually presents as stricture) - Extramural causes

CA of bronchus Mediastinal LN enlargement Aortic aneurysm Anomalous Rt subclavian artery (short, smooth narrowing, crosses behind the upper esophagus)



Dilatation of esophagus Types (Obstructive and non obstructive) Dilatation+ obstruction is associated with stricture The patient with CA usually presents with dysphagia (stricture) before the esophagus becomes dilated Markedly dilated esophagus indicates long standing condition E.g. achalasia or benign stricture Dilatation with out obstruction occurs in scleroderma (no obstruction, no peristalsis, dilatation)

Varices Appear as a lucent, tortuous, worm like filling defects with distort a mucosal pattern, so that a folds are no longer parallel do endoscopy.

Esophagus web Web is a thin shelf like projection arising from anterior wall of the cervical portion of the esophagus, combination of web+ dysphagia+ iron deficiency anemia Plummer Vinson syndrome.

Diverticula Are saccular out pouchings which are often seen as chance findings in the intrathoracic portion of the esophagus, pharangeal pouch of zenker’s diverticulum is important

1- retention of food 2- pressure effect 3- Displace the esophagus.

Esophageal atresia Several different types exist, commonest is in upper part of esophagus ending blindly, the lower part has fistula with tracheobronchial tree ..pass soft tube into the esophagus coiling, holds up.

Candidiasis Severely ill patient, in immunocompromised, it causes mucosal ulceration which is seen as fine irregularities projecting from the lumen of the esophagus.

Normal barium meal: STOMACH AND DUODENUM 6 RA

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STOMACH AND DUODENUM Barium meal is a contrast study of the stomach and duodenum, 200 ml of barium at least 6hr fasting prior to examination both erect and lying flat Double contrast examination (barium and gas) the stomach is distended with a gas producing agent + I.V injection of short acting MM relaxant to provide better mucosal detail.

Normal barium meal:

Check each part of the stomach and duodenum I. No abnormal narrowing present

II. The outline of lesser curve of stomach is smooth with no filling defects or projection

III. Greater curve is nearly always irregular due to prominent mucosal folds IV. The Duodenal cap or bulb is nearly triangular in shape + short pyloric canal V. The duodenum forms a loop around the head of pancreas to reach the

duodenojejunal flexture VI. Diverticula of the end part of the duodenum is common finding

Gastroscopy:

Gastroscopy and Ba meal are complementary

Indications: − Demonstrating mucosal lesions such as gastritis − Histological Ex − Persistent dyspepsia − Follow up of ulcer − Ex of the patient after gastric surgery − Dx of cause of acute bleeding

Abnormal barium meal findings

- Filling defects - GU - Narrowing



- Thick gastric mucosal folds - Gastric outlet obstruction - Gastritis - Hiatus hernia - DU

Filling defects (intarluminal, intramural, extramural) UCauses:U CA, leiomyoma, polyp. CA is a commonest cause of filling defect in the stomach of adult

CA - Irregular filling defect - Altered normal mucosal pattern - Shouldering edges - CA of the fundus may obstruct the esophagus - CA of the antrum gastric outlet obstruction - Diffuse CA called linitis plastica

Leiomyoma Smooth rounded filling defect …ulcer on its surface, if present is characteristic feature .

Polyps - Single or multiple - Sessile or pedunculated - Benign or malignant

Intarluminal defects E.g. food, blood….completely surrounded by barium …mobile .

GU Either benign (mostly on lesser curve) or malignant on the greater curve View profile (projecting outside) Enface (ulcer crator) Dx: endoscopy, biopsy Features enfavouring a benign ulcer:

- Ulcer on the lesser curve - Projecting beyond the lumen

Abnormal barium meal findings STOMACH AND DUODENUM 8 RA

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- Radiating mucosal folds reaching the edge of ulcer crator (rounded collection of barium)

narrowing If constant malignancy When involves a whole stomach linitis plastica = leather bottle stomach Linitis plastic:

a- Generalized narrowing b- Thick rigid tube c- No peristalsis d- Obliteration of the mucosal folds e- Rapid gastric emptying

UCauses of localized narrowing Infiltrating CA Active ulcer spasm Ulcer healed by scar and fibrosis

Thick gastric mucosal folds Associated with high acid secretion UCauses

− DU − Zollinger- Ellison syndrome − Gastritis due to H. pylori − Lymphoma

Gastric outlet obstruction In most patient barium rapidly leaves the stomach to enter the duodenum, but in others this only occurs after the patient has been lying down on the right side for several min, in gastric outlet obstruction 50% of the barium leaves the stomach after 4 hr, or even 24 hr stomach will be large, contains food residues. UCauses

- Chronic DU (deformed, stenosed duodenal cap) - CA antrum - Pyloric stenosis (In infant is the commonest cause)

Dx. U/S, clinical



Gastritis Erosive gastritis alcohol, aspirin Double contrast barium meal … erosions appear as: Small, shallow collections of Ba, surrounded by a radiolucent halo due to edema .

Hiatus hernia Types: Sliding and rolling (para esophageal)

- Sliding (more common) GE junction+a portion of stomach are above the diaphragm Incompetent cardiac sphincter, so reflux occurs and may cause esophagitis, ulceration and peptic stricture.

- Rolling Fundus of the stomach herniates GE junction in normal position and competent cardiac sphincter

DU Rarely malignant could be bulbar (common) or postbulbar URadiological features:

- Ulcer crater - Lucent zone around it due to edema - Mucosal folds are often seen radiating toward the ulcer - Deformed from scarring due to chronic ulcer

No need for follow up by barium meal not possible to comment, it doesn’t undergo malignant changes

Upper GI bleeding:

do gastroscopy UCauses: PU, gastric erosions, varices, CA

SMALL INTESTINE Standard contrast ex. Is Ba follow through, an alternative is enteroclysis (small bowel enema).

Normal Ba follow through: SMALL INTESTINE 10 RA

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Normal Ba follow through:

Position: the small bowel occupies the central and lower abdomen, usually framed by colon. The diameter is normally <25mm. Its appearance depends on the diameter of bowel, when distended the folds seen as lines traversing the bowel called valvulae conniventes, when contracted the folds lie longitudinally and assume feathery appearance when relaxed.

Enteroclysis:

Distends the bowel and gives excellent mucosal details. The disadvantage is it requires intubation with a nasoduodenal tube, Ba is injected through the tube followed by water or cellulose.

This technique is used in cases with structural deformities, e.g. Crohn’s disease or tumors, but not used in cases with malabsorption syndrome.

Abnormal Ba follow through:

look for:

1. Dilatation, which indicates either malabsorption, paralytic ileus or small intestinal obstruction. A value of 30mm is definitely abnormal, valvulae conniventes become clearly visible.

2. Mucosal abnormality, mucosal folds thicken in malabsorption, oedema, hemorrhage in the bowel wall, and when inflamed or infiltrated.

3. Narrowing, normal narrowing is caused by peristalsis, they are smooth, concentric, transient with normal mucosal folds. When there is stricture, it’s caused by crohn’s disease, TB, lymphoma, they don’t contain normal mucosal folds and bowel dilates proximally.

4. Ulceration, may appear shallow or deep. Ulceration is seen in Crohn’s disease, TB, lymphoma... Cobble stone appearance may be seen due to ulceration and mucosal oedema.

5. Alteration in position, in congenital malrotation or displacement by a mass.

Crohn’s disease:

Is a disease of unknown cause, characterized by:

1. Localized area of non-specific chronic granulomatous inflammation. 2. Nearly always affects the terminal ileum. 3. Skin lesions involve several different parts of SI and LI, leaving normal remaining

bowel. 4. Stricture. 5. Mucosal abnormality. 6. String sign, severe narrowing of a loop of bowel from spasm in the ulcerated part or

from oedema and fibrosis and proximal dilatation. 7. Cobble stone appearance.



8. Thickened bowel wall and mucosal folds. 9. Inflammatory mass which displace the loops. 10. Fistulae to other loops of bowel, bladder and vagina. 11. Malabsorption features.

Tb:

Is indistinguishable from crohn’s disease by Ba meal. Commonly affects ileocecal valve and causes contraction of the caecum.

Lymphoma:

- Small mucosal filling defects due to tumor nodules. - Displacement of the loops by enlarged LN. - Liver and spleen enlarged.

Malabsorption:

Definite Dx It is by jejuna biopsy. Ba follow through is useful only to:

- Show structural abnormality that causes the malabsorption. - Help to make the definite Dx in doubtful cases when biochemical tests are

normal.

Signs: 1. Small bowel dilatation. 2. Thickened mucosal folds. 3. Flocculation and dilution of Ba in advanced cases.

In the following conditions no clue to the cause can be obtained by Ba study:

1. Diffuse mucosal lesion: − Gluten enteropathy − Tropical sprue

2. Deficiency of absorptive factors e.g bile or pancreatic enzymes. 3. Postgastrectomy.

In the following conditions the cause of malabsorption can be obtained:

1. Crohn’s disease 2. Lymphoma 3. Anatomical abnormalities:

• Decreased length of the bowel • Stagnation of bowel contents, diverticula, blind loop, stagnant loop.

Disaccharidase deficiency:

1. Ba rapidly reaches the colon

Acute SI obstruction: LARGE INTESTINE 12 RA

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2. Small bowel becomes dilated 3. Diluted Ba.

Acute SI obstruction:

Clinical + plain abdominal film

1. Bowel proximal to the obstruction is dilated. 2. Diluted Ba, by excessive fluid in the bowel.

LARGE INTESTINE Standard ex of the LI are: Ba enema (single contrast or double contrast), endoscopy (either sigmoidoscopy for rectum, or colonoscopy which is complementary).

Indications for colonoscopy:

1. Inspecting and taking biopsy of abnormalities seen in Ba enema. 2. Patient with persistent symptoms with a normal Ba enema. 3. Screening of a patient with a strong family Hx of colonic Ca. 4. Performing polypectomy. 5. Assessing the extent of ulcerative colitis and crohn’s disease.

Normal Ba enema:

Length of colon is very variable, there are redundant loops especially in sigmoid and transverse colon. Caecum is usually located in the right iliac fossa, but may be under the right lobe of liver or even in central abdomen. Haustrations usually recognized but may be absent in the descending colon and sigmoid colon, the outline of distended colon is smooth.

Abnormal Ba enema:

Narrowing, dilatation, filling defects, diverticulae, ulceration, displacement of the colon.

Narrowing of the lumen: causes are: spasm, stricture, and compression by an extrinsic mass.

• USpasm:U is smooth concentric narrowing, it can be abolished by i.v. mm relaxative e.g. buscopan.

• UStricture:U main causes are Ca, Diverticular disease, crohn’s disease, ischemic colitis. Rare causes are TB, lymphogranuloma venerum, amoebiasis and radiation fibrosis.

Should be born in mind: 1. Neoplastic strictures have shouldering edges, irregular lumen and > 6cm in length. 2. Benign strictures have tapered ends, smooth outline of any length. 3. Ulceration maybe seen in strictures due to crohn’s dis.



4. Stricture due to diverticular disease is accompanied by other signs. 5. The site of the stricture can help, e.g.:

− Diverticular disease is almost always confined to sigmoid colon − Ischemic strictures located between splenic flexure and sigmoid colon − Crohn’s dis and TB at caecum − Sacculation of colon in ischemic stricture

Extrinsic compressions have smooth narrowing from one side only, often displace the colon. Smooth indentation on the caecum maybe seen with appendicular mucocele, appendicular abscess, and inflammatory mass and in crohn’s.

Dilatation of colon: This is difficult to assess especially double contrast study which involves distention of colon and depends on the amount of Ba and air introduced… causes are:

1. Obstruction 2. Paralytic ileus (Dx is clinical) 3. Valvulus 4. Ulcerative colitis with toxic dilatation 5. Hirschsprung’s disease with megacolon

Filling defects in the colon: Intra luminal, intra mural, and extra mural.

Localized filling defects: CA, polyp, feces, the feces have no attachment to the wall and completely surrounded by Ba or air, more freely… so preparation of the patient before Ba enema is needed.

Multiple smooth filling defects in the wall (intramural) are caused by hemorrhage of the wall, oedema, or pneumatosis. Intussusception is a unique type.

Ulceration of colon: They are small projections from the lumen into the wall of the bowel. This results in fuzzy or shaggy appearance.

Causes: 1. Ulcerative colitis (common). 2. Crohn’s disease (common). 3. TB (rare). 4. Amoebic dysentery (rare). 5. Bacillary dysentery (rare).

Tumors of the colon: LARGE INTESTINE 14 RA

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Tumors of the colon:

Polyp means a small mass of tissue arising from the wall of the bowel, projecting into the lumen. They are either sessile or pudenculated, single or multiple, neoplastic, inflammatory or developmental, benign or malignant. They are best examined by a double contrast Ba-enema.

Features suggesting malignancy: 1- Diameter more than 2cm 2- Short thick stalk 3- Irregular surface 4- Rapid rate of growth

Types: 1- Adenomatous polyps: are benign, single or multiple, mostly found in rectosigmoid

junction, in familial polyposis there are numerous polyps, one or more will change into carcinoma.

2- Villous polyps: benign, sessile tumors, having sponge-like appearance, frequently mistaken for feces, mostly found in the rectum and cecum, having high incidence to change to Carcinoma.

3- Polypoid adenocarcinoma 4- Juvenile polyps: almost all isolated polyps in children. 5- Inflammatory polyps (pseudopolyps), seen in ulcerative colitis. 6- Hyperplastic or metaplastic polyps.

Carcinoma Sites are rectosigmoid and cecum. Types are annular carcinoma, polypoid carcinoma or fungating. Annular carcinoma shows irregular stricture with shouldered edges, rarely more than 6cm in length. Polypoid or fungating carcinoma → irregular filling defects projecting into the lumen.

CT scan is alternative to Ba-enema as: 1- For very elderly or frail patient. 2- Show carcinoma. 3- Show spread and invasion. 4- Show metastasis. 5- Show postoperative recurrence.



Hirschsprung’s disease

Is due to absence of ganglionic cells, usually in sigmoid or rectosigmoid junction. The aganglionic segment, usually the rectum, is either normal or small at Ba-enema and diagnosis depend on recognizing the transitional zone from the normal, or reduced calibred colon to the dilated colon. The colon is not wasted out before the Ba-enema as water intoxication occurs.

Idiopathic megacolon

Chronic constipation is the cause, Ba- enema shows both rectum and colon are dilated and contain large amounts of feces; the rectum is large in size.

Acute Bleeding (S and L bowel)

Meckel’s diverticulum in children may lead to unexplained bleeding. For bleeding we do:

1- Angiography 2- Radionuclide study

High uptake is seen in stomach and in any gastric mucosa within a meckle’s diverticulum. Ba-enema should be avoided as a first examination.

HEPATOBILIARY SYSTEM Methods of imaging:

Non invasive like plain X-ray, contrast study, ultrasound, CT scan, MRI, radionuclide. Invasive methods like PTC, ERCP, and selective arteriography. Ultrasound particularly useful for GB disease, cyst, abscess and perihepatic fluid collection. CT, MRI for mass lesion detection.

Normal liver:

UUltrasound U of normal hepatic parenchyma include:

1- Uniform echo-reflectivity. 2- Low and medium amplitude echoes. 3- Interspersed with bright echoes of portal triad and echofree areas of large

hepatic veins and portal vein.

Liver masses: HEPATOBILIARY SYSTEM 16 RA

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UCT scan:U I.V contrast often given to increase density of normal liver parenchyma and to produce a different density between the normal parenchyma and the lesion, which enhance poorly except hemangiomas. URadionuclied Liver image U: almost completely replaced by ultrasound, CT, MRI. UMRI:U is used as a problem-solving technique to give additional information to ultrasound and CT.

Liver masses:

Ultrasound, CT, MRI decide whether mass is present or not, and differential diagnosis can be suggested, but Biopsy is the definitive diagnosis.

Masses include the following: I. Liver neoplasm: either primary (hepatoma, lymphoma) or secondary’s from the

stomach, colon, pancreas, breast, lung) . Secondaries are more common than primaries.

II. Liver cysts: a- Congenital: This could be single or multiple. b- Infection. c- Adult polycystic disease. d- Hydatid cyst.

III. Hemangiomas on ultrasound resemble neoplasm, but at CT scan like normal liver tissues, however at MRI its uniform with very high density on T2 (light bulb sign).

Liver cysts UUltrasound:

Ultrasound can show typical features of a cyst which include:

1- Sharp margin. 2- No echoes within the cyst. 3- Intensive echoes from the front and back of the cyst. 4- Posterior enhancement.

UCT scan:

1- Very well defined margin. 2- Attenuation values similar to that of water.

Lesions below 2cm in diameter are difficult to distinguish from solid neoplasm, and less than 1 cm almost never distinguishes cysts from solid lesions.

UMRI:



like CT scan

1- Low signal on T1- weighted scan. 2- High signal on T2- weighted scan.

As a rule most pathologies are bright on T2, dark on T1 except fat.

Liver abscess: Structurally it’s similar to cysts, but usually they can be distinguished, as they have thicker wall, fluid centers, more regular and more obvious. At ultrasound a layer of necrotic debris may be seen within the abscess. Occasionally chronic abscess calcify. At CT scan attenuation value usually higher than water, but may be similar to water. Note: abscess can usually be distinguished from necrotic tumors at Ultrasound, CT, MRI, but the clinical situation should aid in making distinction. Aspiration under ultrasound guidance is invariable.

Liver trauma:

CT scan is the best technique as it surveys other organ injuries like kidney or spleen. Injuries could be either parenchymal laceration or subcapsular hematoma. CT scan shows:

1- Low density usually. 2- Occasionally isodense. 3- Occasionally high density due to blood clot.

Differential diagnosis: artifact, pre-existing mass lesion. Liver trauma is the commonest abdominal injury that leads to death.

Liver cirrhosis and portal hypertension:

Causes of portal hypertension are: 1- Cirrhosis. 2- Budd chiari syndrome. 3- Thrombosis.

Signs on ultrasound and CT scan are:

1- Reduction in the size of right lobe of the liver. 2- Splenomgaly. 3- At ultrasound the texture of liver is diffusely abnormal. 4- At CT scan normal, until late in the disease.

Fatty degeneration of the liver: HEPATOBILIARY SYSTEM 18 RA

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Portal venography: assess the patency of the portal vein. Contrast is injected into the celiac axis, splenic artery and superior mesenteric artery.

Treatment is portocaval anastomosis. And TIPSS (Transjugular Intrahepatic Portosystemic Stent Shunt).

Fatty degeneration of the liver:

Is frequent finding, either whole liver affected or sections. Ultrasound shows:

1- Increased echogenecity, called bright liver. 2- Similar to that of centre of the kidney which is echo-complex.

CT scan: 1- Low density. 2- Vessels are relatively highly attenuated structures against a background of low-

density parenchyma. MRI: is useful in problem cases, shows characteristic set of signal for fat.

Biliary system

Ultrasound UUS U is the best method of investigation because it is:

1. Simplest. 2. Best for showing gall stones. 3. Best for diseases of GB. 4. Excellent for confirming or excluding BD dilatation.

CT UCTU can also show these, but U/S is less costy and gives more information.

as the GB is a fluid filled organ. It is particularly amenable for U/S examination, because it is important that GB should be full of bile and the patient asked to fast, to prevent GB contraction. The normal GB wall is thin. GB wall is thickening in acute & chronic cholecystitis. Gall stone greater than 1-3 cm can be seen.

It is usually imposible to diagnose cystic duct obstruction by U/S, so we use radionuclide. The CBD & common hepatic duct can be visualized in almost all patients, but the lower end of CBD is obscured by the duodenum.

Radionuclide scan: IDA (imino-diacetic acid) labeled with Tcm99 is used. The main uses are in:



1. Suspected acute cholecystitis. 2. Obstruction of cystic duct.

The patient should fast for 4 hours prior to injection. Hepatic excretion occurs despite high serum bilirubin levels, so these agents can be used in jaundiced patients. Normally the GB, CBD, duodenum & SI are seen within first hour, confirming the patency of both cystic duct & CBD. If we see CBD, duodenum, SI, within first hour, but GB not visualized so cystic duct obstruction considered.

ERCP: indications:

1. To determine the cause of jaundice in patient with large duct obstruction. 2. Unexplained abdominal pain thought to be biliary in origin when other

investigations have been equivocal. 3. To demonstrate CBD in patients undergoing laparoscopic cholecystectomy

especially when history & biochemical investigation suggest stone in CBD.

Others Oral cholecystography: iodine is used, now replaced by U/S. PTC: alternative to ERCP, the patient usually jaundiced, done in LA. MRCP: no need for contrast.

Gall stones and chronic cholecystitis

Are frequent findings, especially in middle aged females. There is cause of recurrent upper abdominal pain, but presence of stone does not necessarily mean the pain is due to stone. 20-30% are radio-opaque.

Plain film: 1. Shows 20-30%. 2. Vary in size and shape. 3. Dense outer rim with central lucency. 4. Calcified sludge with the GB, known as “milk of calcium bile”

U/S: 1. Strongly echogenic foci seen in dependent portions of GB. 2. Posterior shadowing behind the stone is very important as it is not seen in polyp.

Polyp of GB is small, not neoplastic, it is aggregation of cholesrol. Although U/S is accurate for diagnosis of gall stones, is less reliable for diagnosis of CBD stones.

Acute cholecysitis HEPATOBILIARY SYSTEM 20 RA

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In adenomyomatosis, the GB wall is thickened and may show altered echogenesity of the wall, due to Rokitansky- Aschoff sinuses (small projections of the lumen into the wall).

Acute cholecysitis

U/S: usually detect

1. Stone. 2. Inflammatory debris. 3. GB wall thickening. 4. Oedema adjacent to the wall of GB (is very important sign in distinguishing between

chronic & acute cholecystitis). 5. Ultrasonic murphy’s sign is helpful.

In hepatobiliary radionuclide scan actually answer the question “is the cystic duct patent?” mostly obstructed in acute cholecystitis.

Jaundice:

imaging used to diagnose the obstructive causes of jaundice, which are:

1. Impacted stone in CBD. 2. CA of head of pancreas. 3. CA of ampulla of vatar.

US shows: 1. Dilated intrahepatic biliary ducts seen as serpentine structures, parallel to the portal

vein, called double-channel sign. 2. CBD lies just infront of the portal vein and is dilated when more than 7 mm in

diameter. 3. If there is large duct obstruction, the biliary tree will be dilated down to the level of

obstruction.

CT-scan: Two points should be appreciated:

1. Substantial dilatation of the common hepatic duct and CBD may be present with only minimal dilatation of the intrahepatic ducts.

2. The intrahepatic biliary tree may not dilate at all, within the first 48 hours after the obstruction.



Others ERCP or PTC may be used. Radionuclide scan to show the obstruction.

SPLEEN AND PANCREAS Spleen:

By U/S there is homogenous appearance with the same echo density as the liver. CT and MRI are excellent for splenic masses (cysts, abscess, lymphomas) much common than metastasis. Conditions that lead to splenic enlargement with no change in splenic texture on U/S and no change in density on CT:

1. Lymphoma. 2. Portal hypertension. 3. Chronic inflammation. 4. Hemolytic anemias. 5. Leukemias.

The spleen is the most commonly injured organ in blunt abdominal trauma (laceration, contusion and hematoma). CT is superior to U/S for splenic injury, as it shows:

1. Other organ injuries. 2. Intraperitoneal bleeding.

Pancreas:

Pancreatic masses: usual causes are

1. CA pancreas 2. Neoplasm of adjacent LN. 3. Focal pancreatitis. 4. Pancreatic abscess. 5. Pseudocyst.

Adenocarcinoma of pancreas Adenocarcinoma of pancreas: in the head jaundice. In the body and tail enlargement pain. Measurement is not useful in diagnosing masses.

Pancreas: SPLEEN AND PANCREAS 22 RA

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The important signs in both CT and U/S are: 1. Focal mass deforming the outline of the gland. 2. Irregular obliteration of the fat around the pancreas. 3. If contrast used on CT, the tumor is relatively low in density than normal pancreatic

tissue.

Acute pancreatitis Diagnosis is clinical and biochemical. For complication, imaging is beneficial. Clinically, there is abdominal pain, fever, vomiting, leukocytosis.. Biochemically, increased serum amylase. The findings on CT and U/S vary with the amount of hemorrhage, necrosis and suppuration… the signs are: 1. Pancreas usually enlarged, often diffusely enlarged. 2. Irregular outline. 3. low density areas at CT. 4. Echo-poor area at U/S. 5. In very sever cases large fluid, filled area abscess. 6. Pseudocyst (thin or thick, within or adjacent to panceas, vary in size…).

Chronic Pancreatitis Results in:

1. Fibrosis, calcification, ductal stenosis and dilatation. The calcification in panceatitis is mainly due to small calculi within the pancreas, so often recognizable on plain film U/S and particularly CT.

2. Pseudocyst, just like acute type. 3. Enlargement… Either focal (rare and mistaken with CA) or general enlargement. 4. Atrophy: is non specific sign as it occurs in elderly and distal to CA... Maybe focal or

general. 5. Pancreatic duct may enlarge and irregularity seen ERCP shows generalized irregular

dilatation of the duct system.

Pancreatic trauma Pancreatic trauma is uncommon, but serious. CT is the best. Ex. Laceration, hematoma…



PERITONEAL CAVITY AND RETROPERITONEUM Peritoneal cavity

Ascites U/S, CT and MRI can demonstrate very small amount of ascites more little than the amount needed for clinical or plain film detection, but no imaging technique can distinguish the nature of the fluid (exudates or transudate).

- In supine position fluid collect in dependant portion (pouch of doglas →anterior to upper rectum), (Morrison’s pouch in space anterior to Rt kidney) and in para colic gutter.

- If large amount of fluid are present, fluid will be seen throughout the peritoneal cavity and stomach or ………… may be seen floating in the ascites.

a- At CT scan, ascites is of lower density than liver, spleen and kidney. • One of the easiest site to see ascites is near the liver, a uniform band of low density

can identify with liver and diaphragm • Ascites cannot collect posterior to the upper part of liver because of the peritoneal

reflection forming the so called bare area. • When loculated ascites is seen as discrete collection of fluid. Loculated lesion may

not be distinguishable from fluid in abscess because the density of infected and uninfected fluid can be identical.

b- On U/S, ascites seen as echofree regions and often in bowel dilatation with excess gas.

Peritoneal tumors Most common tumor is metastasis from abdominal or pelvic tumors, especially CA of ovary. U/S and CT may show only ascites or peritoneal nodule in ovarian carcinoma numerous nodules may coalesce to form what is called omental cake.

Intra peritoneal abscess - May follow perforation of bowel or biliary tract. - Either sub hepatic, Subphrenic, Para colic and pelvic. - Multiple abscesses are not uncommon. - Ascites frequently follow abdominal and pelvic abscess. - CT is diagnostic but U/S may be just informative.

Disadvantage of US: - Bowel gas interfere it. - Surgical wound and dressing.

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U/S is quick and simple to perform.

US appearance: The best area for US is Rt upper quadrant and true pelvis.

- Search for any localized fluid collection outside the bowel by US by observing peristaltic activity. Abscess assumes many different configurations depending on the adjacent organs.

- The abscess has slightly irregular walls and may contain internal echoes due to septation or debris. these internal echoes are not specific for infection.

- Gas in the abscess appears echogenic and produce acoustic shadowing but it’s difficult to differentiate from gas in the bowel.

CT appearance of abscess - The fluid center of the abscess is identified as homogenous density surrounded by a

definite wall of soft tissue with the peritoneal cavity but outside the bowel. - Gas within the abscess seen in ½ of patients. It is very useful sign to distinguish

infected and non infected fluid loculation. - The gas may take the form of multiple small streaks or bubbles, or may collect as one

large bubble. - Air fluid level may be present within the larger collection. - The wall of the abscess show enhancement following IV contrast administration. - Subphrenic abscess is difficult to distinguish from pleural empyma (US is very

useful).

DD of intra peritoneal abscess 1- Fluid within distended or matted bowel loop. Oral contrast given appears as

opacification of bowel. 2- Loculated uninfected fluid (of ascites, blood or LN). Differentiation between

infected and non infected fluid may be done by aspiration of fluid.

Retroperitoneum

CT, MRI and US, all provide information about the retroperitoneum structures.

Plain film is of limited role to show:

- very large mass - Calcification within the mass - Gas in the abscess - Calcification of aortic aneurism



Retroperitoneal organs: - Adrenal gland - Lymphadenopathy - Aortic aneurism - Retroperitoneal tumors - Hematoma - Abscess

CT CT is particularly informative in obese patient because fat surrounds important structures. It’s difficult in non obese specially children.

In CT look for:

- Complete outline of aorta and inferior vena cava should be clearly visible throughout their length except when inferior vena cava passes through liver. The aorta is round in cross section and measures 2-2.5 cm and the IVC is round to oval.

- There is usually fat containing space to left of aorta which is a good area to look for Lymphadenopathy. The only structure other than LN to be seen in this space is left renal vein.

- The psoas muscles are seen as symmetrical rounded structures. - Both adrenal are well seen in most subjects.

US Retroperitoneal fat is very echoreflective. Aorta and IVC easily identified, also enlarged LN, normal adrenal gland rarely visible.

MRI Provide little advantage in retroperitoneal ∆.

Retroperitoneal Lymphadenopathy - The normal Para aortic LN vary in size from invisible to 1cm in retrocrural area the

upper limit of normal is 6 mm. - Size is the only criterion of abnormality normal, inflammatory and neoplastic nodes

usually have the same features and texture at CT, US & MRI. - Enlargement of over 2 cm is almost always neoplastic, but less than 2cm may be

inflammatory or neoplastic.

Adrenal glands - The normal adrenal glands are thin, bilobed structure surrounded by fat. - Calcification of adrenal gland may follow: • Old intra adrenal hemorrhage.

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• Old healed TB - Severe destruction or calcification may lead to Addison’s ∆ - Enlargement may be due to • Neoplasm • Hyperplasia • Cyst • Abscess • Hemorrhage - Advantage of US and MRI over CT ; • Display retroperitoneum in any plane • Shoe relationship of masses to adjacent organ

Functional adrenal gland tumors Primary → CT occasionally MRI

Secondary → distinction between adrenal adenoma, pituitary tumor , adrenal hyperplasia in Cushing syndrome depend on biochemical test and clinical.

• Adrenal adenoma can lead to Cushing ∆, it’s always >2cm and CT can localize it. • Most hyper plastic gland in pituitary dependant Cushing ∆ are normal or only

slightly enlarged at CT. • Aldosteronoma (Conn’s tumor) are usually < 1 cm and may be difficult to be

identified. • Phaeochromocytomas: are - Very large at CT or MRI - 10% are bilateral, 10% multiple, 10% malignant, 10% outside the adrenal gland.

S.T radionuclide scan used which localize functioning adrenal tumors.

Non-functioning adrenal tumors • Indistinguishable at CT or US • MRI is very helpful • Non functional adenoma larger than 3cm are rare, may be due to metastasis or

primary adrenal carcinoma. The common malignant adrenal tumor is neuroblastoma.

• Metastasis are frequently bilateral, also adrenal abscess and hemorrhage are usually bilateral and indistinguishable at ct.



Retroperitoneal tumor - The commonest one is liposarcoma and fibrosarcoma. - They appear as mass on CT, US, or MRI sometimes the edge of the mass is well

defined but sometimes invade the surroundings.

Aortic aneurism CT, US, and MRI used for diagnosis

• Both CT and US used as a screen exam for aortic aneurism in older men. CT + US used to measure diameter of aortic aneurism and identify the wall and any lining thrombus you can also see any retroperitoneal bleeding from an aneurism at CT. At CT aneurism >6cm are in serious danger of rupture.

• At angiography the outline of aortic lumen seen this is due to thrombus and not the wall that form the outline.

• Aortography is of limited use in assessing the diameter although it is a good technique for the aorta above the aneurism.

• Plain film can also show the aneurism but only if substantial calcification is present in the wall.

Retroperitoneal hematoma - Usually due to trauma or bleeding from an aortic aneurism, it’s sometimes

spontaneous in patient on anticoagulant therapy or bleeding tendency. - Diagnosis is readily made by CT, MRI or US. - Hematoma may have similar feature to non fatty retroperitoneal tumor on CT and

US. - Recent hemorrhage may show area of high density, while older hematoma have

often undergone liquefaction (area of low attenuation) - MRI may show the characteristic feature of hematoma.

Retroperitoneal abscess and psoas abscess - Are usually due to spread of infection from appendix, colon, kidney, pancreas or

spine. Often found close to organ of origin. - Retroperitoneal abscess have many similar features to tumors and hematoma at

both CT and US. Usually there is evidence of fluid center and gas. - The wall of the abscess may enhance with contrast. - Psoas abscess occasionally seen as an isolated entity which show enlargement of

psoas muscle. - For diagnosis you should compare both psoas muscles.

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- ‘’ All the best ‘’

dr. kawa bilateral

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