Gastrointestinal Imaging

Normal Esophageal Contour Deformities ( Fig. 3.1 )

• Cricopharyngeus

• Postcricoid impressions (mucosal fold over vein)

• Aortic impression

• Left mainstem bronchus (LMB)

• Left atrium (LA)

• Diaphragm

• Peristaltic waves

• Mucosa: thin transient transverse folds: feline esophagus (vs. thick folds in chronic reflux esophagitis); tiny nodules in older adults: glycogenic acanthosis

Gastroesophageal Junction (GEJ) Anatomy ( Fig. 3.2 )

• Phrenic ampulla: normal expansion of the distal esophagus; does not contain gastric mucosa

• A-ring (for a bove; Wolf ring): indentation at upper boundary of the phrenic ampulla

• B-ring (for b elow): indentation at lower boundary of the phrenic ampulla; normally not seen radiologically unless there is a hiatal hernia

• Z-line ( z igzag line): squamocolumnar mucosal junction between esophagus and stomach; not visible radiologically

• C-ring: diaphragmatic impression

• The esophagus lacks a serosa. Upper one-third has striated muscle; lower two-thirds has smooth muscle.

Peristaltic Waves

• Primary contractions: initiated by swallowing; distally progressive contraction waves strip the esophagus of its contents; propulsive wave

• Secondary contractions: anything not cleared from the esophagus by a primary wave may be cleared by a locally initiated wave; propulsive wave

• Tertiary contractions: nonpropulsive, uncoordinated contractions; these random contractions increase with age and are rarely of clinical significance in absence of symptoms of dysphagia; nonpropulsive wave; only peristaltic activity in achalasia

Peristalsis should always be evaluated fluoroscopically with the patient in a horizontal position. In the erect position the esophagus empties by gravity.

Associations

• Iron-deficiency anemia (cervical webs): Plummer–Vinson syndrome

• Hypopharyngeal carcinoma

Imaging Features ( Fig. 3.5 )

• Criteria for diagnosing sliding hernia:

  • Gastric folds above diaphragm

  • Concentric indentation (B-line) above diaphragm

  • Schatzki ring above diaphragm

Associations

• Esophagitis, 25%

• Duodenal ulcers, 20%

Approach

• Maximally distend distal esophagus in horizontal position; distention can be achieved by sustained inspiratory effort

• Determine the type of hernia

• Determine if there is reflux by Valsalva maneuver or Crummy water-siphon test (patient in supine right posterior oblique (RPO) position continually drinks water to see if barium refluxes into midesophagus or above)

Lateral Pharyngeal Pouches

AP esophagram at level of pharynx demonstrates lateral outpouchings through weakness in thyrohyoid membrane. Large in glassblowers and wind instrument players.

Zenker Diverticulum ( Fig. 3.6 )

Pulsion diverticulum originates in the midline of the posterior wall of the hypopharynx at an anatomic weak point known as Killian dehiscence (above cricopharyngeus at fiber divergence with inferior pharyngeal constrictor). During swallowing, increased intraluminal pressure forces mucosa to herniate through the wall. The cause of Zenker diverticulum is not firmly established, but premature contraction and/or motor incoordination of the cricopharyngeus muscle are thought to play a major role. Complications include:

• Aspiration

• Ulceration

• Carcinoma

Killian-Jamieson Diverticulum ( Fig. 3.7 )

• Below cricopharyngeus

• Off midline

• Lateral to cervical esophagus

Epiphrenic Diverticulum

• May occasionally be recognized on chest radiographs (CXRs) by presence of soft tissue mass (often with air-fluid level) that mimics a hiatal hernia.

• Large diverticulum can compress the true esophageal lumen, causing dysphagia.

Traction Diverticulum

• Outpouching of midesophagus as a result of adjacent inflammatory process (e.g., tuberculosis [TB]).

• Calcified mediastinal LNs

Pseudodiverticulosis

Numerous small esophageal outpouchings representing dilated glands interior to the muscularis. Usually occur at >50 years of age. Dysphagia is the presenting symptom. Underlying diseases include candidiasis, alcoholism, and diabetes.

Associated Findings

• Esophageal stricture may occur above and/or below stricture.

• Esophagitis

Imaging Features

• Thin flask-shaped structures in longitudinal rows parallel to the long axis of the esophagus

• Diffuse distribution or localized clusters near peptic strictures

• Much smaller than true diverticula

• When viewed en face, the pseudodiverticula can sometimes be mistaken for ulcers. When viewed in profile, however, they often seem to be “floating” outside the esophageal wall with barely perceptible channel to the lumen; esophageal ulcers almost always visibly communicate with the lumen.

Types

• Infectious (common in debilitated patients)

  • Herpes

  • Candidiasis

  • Cytomegalovirus (CMV)

• Chemical

  • Reflux esophagitis

  • Corrosives (lye)

• Iatrogenic

  • Radiotherapy

  • Extended use of nasogastric (NG) tubes

  • Drugs: tetracycline, antiinflammatory drugs, potassium, iron

• Other

  • HIV

  • Scleroderma

  • Crohn disease (rare)

  • Dermatologic manifestations (pemphigoid, dermatomyositis bullosa)

Imaging Features

• Thickening, nodularity of esophageal folds

• Irregularity of mucosa: granularity, ulcerations

• Retraction, smooth, tapered luminal narrowing, stricture just above GE junction

Infectious Esophagitis ( Fig. 3.8 )

• Herpes simplex

  • Small ulcers, <5 mm

  • Normal mucosa between ulcers

  • More diffuse than reflux ulcers

• Candidiasis

  • Plaque like, reticular

  • Shaggy margins

  • Often involve entire esophagus

• CMV and HIV

  • Typically, elliptical large ulcers but may be tiny ulcers such as herpes

  • Etiologic distinction between CMV and HIV ulcers is important because therapies are different.

  • Behçet disease may have a similar appearance.

• Mycobacterial

  • Ulcers, sinus tracts

Inflammatory Eosinophilic Esophagitis

• Dysphagia may be chronic, history of allergies, eosinophilia

• Segmental proximal or midesophageal mild narrowing

• May involve entire esophagus

  • Increased risk of iatrogenic tear

• Responds to steroids

Imaging Features

• A reticular mucosal pattern, which may be discontinuous in the distal esophagus (short segment), is the most sensitive finding.

• Suspect the diagnosis if there is:

  • Upper or midesophageal stricture accompanied by reticular mucosal pattern below transition or ulcer

  • Low strictures: the majority cannot be differentiated from simple reflux esophagitis strictures, and biopsies are required

Imaging Features

• Pneumomediastinum

• Pleural effusion (left > right)

• Mediastinal hematoma

• Rupture immediately above diaphragm, usually on left posterolateral side (90%)

Imaging Features

• Radiographs are usually normal.

• Intravasation rather than extravasation

• There may be subtle mucosal irregularity.

Types

• Primary (idiopathic)

• Secondary (destruction of myenteric plexus by tumor cells)

  • Metastases

  • Adenocarcinoma invasion from cardia

• Infectious: Chagas disease

Clinical Findings

• Primary occurs predominantly in young patients (in contradistinction to esophageal tumors); onset: 20–40 years

• Dysphagia, 100% to both liquids and solids when symptoms begin

• Weight loss, 90%

Diagnosis

• Need to exclude malignancy (fundal carcinoma and lymphoma destroying Auerbach plexus), particularly in older adults

• Need to exclude esophageal spasm

• Manometry is the most sensitive method to diagnose elevated lower esophageal sphincter (LES) pressure and incomplete relaxation.

Imaging Features ( Fig. 3.11 )

• Two diagnostic criteria must be met:

  • Primary and secondary peristalsis absent throughout esophagus

  • LES fails to relax in response to swallowing

• Dilated esophagus typically curves to right and then back to left when passing through diaphragm.

• There may be minimal esophageal dilation in the early stage of disease.

• Beaked tapering at GEJ

• Tertiary waves

• Air-fluid level in esophagus on plain radiograph

Complications

• Recurrent aspiration and pneumonias, 10%

• Increased incidence of esophageal cancer

Treatment

• Drugs: nitrates, β-adrenergic agonists, calcium blockers (effective in <50%)

• Balloon dilatation (effective in 70%)

• Myotomy: procedure of choice

Imaging Features

• Lack of primary waves in distal two-thirds

• GEJ patulous unless stricture supervenes

• Reflux esophagitis (common)

• Strictures occur late in disease

• Esophagus dilates most when stricture supervenes

Types

• Primary neurogenic abnormality (vagus)

• Secondary reflux esophagitis

Imaging Features

• Nutcracker corkscrew esophagus

• Nonspecific esophageal dysmotility disorders

Imaging Features

• Esophagus

  • Early findings: hypercontractility, distal muscular spasm; normal caliber

  • Classic late findings (denervation): megaesophagus, aperistalsis, bird's beak appearance at GEJ (achalasia lookalike)

  • Esophageal complications:

    • Ulcers, hemorrhage

    • Perforation into mediastinum, abscess formation; carcinoma, 7%

• Colon

  • Megacolon (anal sphincter neuropathy)

  • Sigmoid volvulus, 10%

• Heart

  • Cardiomyopathy (cardiomegaly)

  • Clear lungs, no pericardial effusions

• Central nervous system (CNS)

  • Encephalitis

Types

• Squamous cell carcinoma (SCC; most common worldwide)

• Adenocarcinoma, usually in distal esophagus at GEJ (in the United States, the incidence is now higher than SCC)

• Lymphoma

• Leiomyosarcoma

• Metastasis

Associations

• SCCs are associated with:

  • Head and neck cancers

  • Smoking

  • Alcohol

  • Achalasia

  • Lye ingestion

• Adenocarcinoma is associated with:

  • Barrett esophagus

  • Gastroesophageal reflux disease (GERD)

  • Obesity (probably because of the link with GERD)

Imaging Features ( Fig. 3.14 )

• Staging (CT)

  • Invasion into mediastinum, aorta

  • Local LN enlargement

  • Metastases: liver, lung, lymphadenopathy, gastrohepatic ligament

• Staging (endoscopic US)

  • Extension through wall

  • LN metastases

• Spectrum of appearance

  • Infiltrative, shelf-like margins

  • Annular, constricting

  • Polypoid

  • Ulcerative

  • Varicoid: does not change in configuration during fluoroscopy in contrast to esophageal varices

  • Unusual bulky forms: carcinosarcoma, fibrovascular polyp, leiomyosarcoma, metastases

Imaging Features

• Foreign body usually lodges in coronal orientation.

• It is important to exclude underlying Schatzki ring or esophageal carcinoma once the foreign body is removed.

Patient Preparation

• Nothing by mouth for 8 hours before examination

• If a BE has been performed within the past 48 hours, give 4 tablespoons of Milk of Magnesia 12 hours before examination (cathartic).

Single-Contrast Technique ( Fig. 3.15 )

• 1

  Patient is in upright position and drinks thin barium. Spot GEJ.

• 2

  Prone position to observe esophageal motility. Spot GEJ, antrum, and bulb.

• 3

  Turn supine under fluoroscopic control.

• 4

  Turn left posterior oblique (LPO) for air contrast of antrum, bulb. Evaluate duodenum and proximal SB.

• 5

  Overhead radiographs: LPO, right anterior oblique (RAO) of stomach, PA of abdomen

Double-Contrast Technique

• 1

  Patient upright in slight LPO position. Administer effervescent granules with 20 mL of water. Start patient drinking thick barium (120 mL) and obtain air-contrast spot radiographs of esophagus.

• 2

  Table down with patient in prone position (compression view may be obtained here). Patient rolls to supine position through the left side. Check mucosal coating: if not adequate, turn patient to prone again and back to supine position, roll to keep left side dependent (so that emptying of barium into the duodenum is delayed).

• 3

  Obtain views of the stomach. This is generally the most important part of the study. The patient is turned to get air into different regions of the stomach.

  • Patient supine (for body of stomach)

  • Patient LPO (for antrum)

  • Patient RPO (for Schatzki view for lesser curvature)

  • Patient RAO (for fundus)

• 4

  Views of bulb in contrast and gas relief. First leave the patient in RAO view and then turn to LPO view. Include some C-loop.

• 5

  Study of esophagus. Patient RAO drinking regular “thin” barium. Observe entire esophagus and evaluate motility. Take spot radiographs (routinely of distended GEJ).

• 6

  Overhead radiographs (optional):

  • RAO, drinking esophagus

  • AP of abdomen

  • LPO and RAO stomach

• 7

  Water-siphon test to exclude GE reflux, unless small-bowel follow-through (SBFT) is simultaneously scheduled then done at end after swallowing additional barium

Indications

• Decompression in terminally ill patients with gastric outlet or small bowel obstruction (SBO): gastrostomy is sufficient.

• Feeding: gastrojejunostomy preferred

Technique

• 1

  Half cup of barium the night before to opacify colon. NG tube placement.

• 2

  Mark liver edge under US.

• 3

  Distend stomach by insufflating air through NG tube; mark entry high in midbody pointing toward pylorus, avoid marked colon and opacified bowel.

• 4

  Anesthetic through four 25-gauge needles 1–2 cm away from insertion point. Leave needles in.

• 5

  Gastropexy with T-tacks. Deploy them with 0.35-in ring wire under fluoroscopic guidance. Crimp T-tacks in place.

• 6

  Place needle with guidewire into stomach through central insertion point.

• 7

  Dilators 8, 10, 12, 14 Fr; place 15-Fr peel-away sheath.

• 8

  Place 14-Fr gastrostomy catheter (e.g., Cook). Gastric decompression can be achieved with smaller-bore catheters (>10 Fr). Secure catheter in place.

Contraindications

• Organs overlying stomach: liver, colon, ribs (high position of stomach)

• Massive ascites (perform therapeutic paracentesis before gastrostomy)

• Abnormal gastric wall (ulcer, tumor): hemorrhage is common.

• Elevated bleeding time

Anatomy ( Fig. 3.16 )

• Fundus

• Body

• Antrum

• Pylorus

• Curvatures: lesser, greater

Mucosal Relief

• Gastric rugae (prominent in body, proximal antrum): in double-contrast studies, rugae are more often effaced by gaseous distention.

• Area gastricae (normal gastric mucosal pattern) is most prominent in antrum and body; ectopic duodenal area gastricae is present in 20%.

Mucosal Versus Extramucosal Location of Mass ( Fig. 3.17 )

The location of a lesion can be evaluated by observing the angle the lesion forms with the wall:

• Acute angle (looks like an a ): mucosal (polyp, cancer)

• Obtuse angle (looks like an o ): extramucosal (intramural or extramural)

• Preservation of mucosal pattern is also a hint to location of lesions:

  • Disruption of normal pattern: mucosal

  • Presence of normal pattern: intramural or extramural location

• Distinction of outline:

  • Smooth, distinct: extramucosal

  • Irregular, fuzzy: mucosal

Cause

• Helicobacter pylori (gram negative) plays a major role in the development of peptic ulcer.

  • Not all individuals with H. pylori will develop ulcers. Prevalence of H. pylori: 10% of population <30 years, 60% of population >60 years.

  • Prevalence of H. pylori in duodenal and gastric ulcers: 80%–90%; risk factor for adenocarcinoma and lymphoma

  • Approach:

    • Precaution against infection should be taken by all GI personnel.

    • H. pylori serology may become useful for diagnosis of PUD.

    • PUD heals faster with antibiotics and antacids than with antacids alone.

  • Incidence markedly decreased

Detection

Detection rate of ulcers by double-contrast barium is 60%–80%.

Imaging Features ( Fig. 3.18 )

• Ulcer crater seen en face: distinct collection of barium that persists on different views; the collection is most often round but can be linear.

• Ulcer crater seen in profile: barium collection extends outside the projected margin of the gastric or duodenal wall.

• Double-contrast studies: the crater has a white center with surrounding black “collar.”

• Greater curvature ulcers are commonly because of malignancy or nonsteroidal antiinflammatory drug (NSAID) ingestion. (Aspirin-induced ulcers are also called sump ulcers because of their typical location on greater curvature.)

• Multiple ulcers are usually due to NSAID ingestion.

• Signs of benign and malignant ulcers

Symptoms Mimic PUD

• Causes

  • NSAIDs

  • H. pylori

  • Alcohol

Imaging Features

• Multiple tiny, aphthoid-like erosions throughout antrum, body

• Occurs on rugal folds

• Prominent area gastricae

Treatment

• Identify and treat causal agent

• H2 blockers

Malignant Ulcers (5% of All Ulcers)

• Carcinoma, 90%

• Lymphoma, 5%

• Rare malignancies (sarcoma, carcinoid, metastases)

Complications of Gastric Ulcer ( Fig. 3.19 )

• Obstruction

• Posterior penetration of ulcer into pancreas

• Perforation

• Bleeding: filling defect in the ulcer crater may represent blood clots.

• Gastroduodenal fistulas: double-channel pylorus

Pearls

• Categorize all gastric ulcers as definitely/probably benign or malignant.

• All patients, except for those with de novo definitely benign gastric ulcers, should proceed to endoscopy with biopsy.

• Benign ulcers decrease 50% in size within 3 weeks and show complete healing within 6 weeks with successful medical treatment.

• Benign ulcers may heal with local scarring.

• Ectopic pancreatic rest may contain a central umbilication that represents a rudimentary duct, not ulcer. Commonly located in antrum.

• Gastric diverticulum: commonly in posterior fundus; contains mucosal folds, neck, changes shape during fluoroscopy

Imaging Features

• Giant gastric rugal folds, usually proximal half of stomach

• Hypersecretion: poor coating, dilution of barium

• Gastric wall thickening

• Small intestinal fold thickening because of hypoproteinemia

• Peptic ulcers are uncommon

Clinical Findings

• Abdominal pain, 90%

• Diarrhea, 40%

• Eosinophilia

Imaging Features

• Stomach, 50%

  • Tapered antral stenosis (common)

  • Pyloric stenosis (common)

  • Gastric fold thickening

• SB, 50%

  • Fold thickening (common)

  • Dilatation

  • Luminal narrowing

Clinical Findings

• Diarrhea

• Recurrent PUD

• Pain

Causes

• Gastrinoma, 90%

  • Islet cell tumor in pancreas or duodenal wall, 90%

  • 50% of tumors are malignant

  • 10% of tumors are associated with multiple endocrine neoplasia (MEN) type I

• Antral G-cell hyperplasia, 10%

Imaging Features

• Ulcers

  • Location: duodenal bulb > stomach > postbulbar duodenum

  • Multiple ulcers, 10%

• Thickened gastric and duodenal folds

• Increased gastric secretions

• Reflux esophagitis

Risk Factors

• Pernicious anemia

• Adenomatous polyps

• Chronic atrophic gastritis

• Billroth II > Billroth I

Location

• Fundus/cardia, 40%

• Antrum, 30%

• Body, 30%

Staging

• T1: Limited to mucosa, submucosa (5-year survival, 85%)

• T2: Muscle, serosa involved (5-year survival, 50%)

• T3: Penetration through serosa

• T4: Adjacent organs invaded

Imaging Features ( Fig. 3.20 )

Features of early gastric cancers:

• Polypoid lesions (type 1)

  • >0.5 cm (normal peristalsis does not pass through lesion)

  • Difficult to detect radiographically

• Superficial lesions (type 2)

  • 2A: <0.5 cm

  • 2B: most difficult to diagnose (mucosal irregularity only)

  • 2C: 75% of all gastric carcinoma (folds tend to stop abruptly at lesion)

• Excavated lesion (type 3) = malignant ulcer

Features of advanced gastric cancer:

• Malignant ulcer: folds short of collar

• Ulcerated luminal mass

• Rigidity, diffuse narrowing: linitis plastica

• Thickened wall >1 cm by CT

• Lymphadenopathy

  • Gastrohepatic ligament

  • Gastrocolic ligament

  • Perigastric nodes

• Hepatic metastases

Risk Factors

• H. pylori infection

• Inflammatory bowel disease (IBD)

• Celiac disease

Imaging Features

• • Diffuse infiltrating disease

• Normal gastric wall 2–5 mm (distended stomach) ≥6 mm is abnormal except at GEJ

  • Thick folds

  • Ulcerating mass

  • More often than carcinoma, lymphomas spread across the pylorus into the duodenum.

  • Hodgkin lymphoma of the stomach mimics scirrhous carcinoma (strong desmoplastic reaction).

Imaging Features

• Exophytic masses of stomach or SB that may ulcerate; obstruction rare despite size

• Heterogeneous contrast enhancement

• Crescent-shaped necrosis (Torricelli-Bernoulli sign) in large GIST

• 30% show aneurysmal dilation of enteric bowel.

• Liver is the most common site of metastases, followed by mesentery.

• Mesenteric metastases are smooth and multiple.

• Lymphadenopathy not common; if lymphadenopathy is present, consider alternate diagnosis of lymphoma.

• Good response to Gleevec (competitively binds to ATP binding site of tyrosine kinase, leading to cell death by apoptosis; areas of apoptosis appear as cystic spaces on CT or magnetic resonance imaging [MRI])

• positron emission tomography (PET) is a sensitive modality for follow-up of patients on therapy.

Contiguous Spread

• From colon (gastrocolic, gastrosplenic ligament)

• From liver (gastrohepatic ligament)

• From pancreas: direct invasion

Hematogenous Spread to Stomach (Target Lesions)

• Melanoma (most common)

• Breast

• Lung

Imaging Features

• Diffuse uniform thickening, nondistensible, absent gastric folds, linitis plastica

• Multiple lesions with bull's eye appearance: sharply demarcated with central ulcer (much bigger than aphthoid ulcer)

Mucosal Relief

• Folds in the duodenal bulb are longitudinally oriented.

• In the descending portion of the duodenum, Kerkring folds are transversely oriented.

• These folds are usually visible despite complete duodenal distention.

Papilla ( Fig. 3.23 )

• Major papilla (Vater papilla): orifice for ducts

  • Appears as round filling defect

  • Located below the promontory

  • 8–10 mm in length

  • Abnormal if >15 mm

• Minor papilla (accessory papilla, Santorini papilla)

  • Located superiorly and ventral to major papilla

  • Mean distance from major papilla 20 mm

  • Not usually visualized

• Promontory:

  • Shoulder-like luminal projection along medial aspect of the second portion of the duodenum

  • Begins superior to major papilla

Predisposing Factors

• Chronic obstructive pulmonary disease (COPD)

• Severe stress: injury, surgery, burn

• Steroids

Imaging Features

• Persistent round or elliptical collection; radiating folds, spasm

• Linear ulcers, 25%

• Kissing ulcers: 2 or more ulcers located opposite each other

• Giant ulcers

  • Crater is >2 cm.

  • Ulcer largely replaces the duodenal bulb.

  • A large ulcer crater may be mistaken for a deformed bulb but does not change shape during fluoroscopy.

• Duodenal ulcers often heal with a scar; this can lead to deformity and contraction of the duodenal bulb: cloverleaf deformity, or hourglass deformity.

• Postbulbar ulcers: any ulcer distal to the first portion of the duodenum should be considered to have underlying malignancy until proved otherwise (only 5% are benign ulcers, mostly secondary to Zollinger-Ellison syndrome).

Location of Intestinal Trauma

• Duodenum/proximal jejunum, 95%

• Colon, 5%

Types of Injuries

• Perforation (requires surgery)

• Transection (requires surgery)

• Hematoma (nonsurgical treatment)

Imaging Features

• Perforation:

  • Extraluminal retroperitoneal gas

  • Extravasation of oral contrast material

• Perforation or hematoma:

  • Thickening of duodenal wall or high-density mass (clotted blood) can narrow the lumen

  • Fluid in right anterior pararenal space or in the peritoneum

  • Duodenal diverticula commonly project into head or uncinate process of pancreas and rarely present coming from lateral wall.

Surgical Treatment

• Simple repair

• Pyloric exclusion for complex injuries

• Whipple procedure is rarely necessary.

• Surgical complications:

  • Intraabdominal abscess, 15%

  • Duodenal fistula, 4%

  • Duodenal dehiscence, 4%

  • Pancreatic fistula, 1%

Types

• Lipoma, leiomyoma (most common)

• Villous adenoma (cauliflower-like), adenomatous polyp

• Lymphoid hyperplasia

• Heterotopic gastric mucosa: small angular filling defects in bulb, larger than nodules of lymphoid hyperplasia and smaller than Brunner gland hyperplasia

• Brunner gland hyperplasia

• Ectopic pancreas

Imaging Features

• Lobulated stellate filling defect in the duodenal bulb

• Filling defect in contiguity with antral rugal folds

Types

• Adenocarcinoma (most common)

• Leiomyosarcoma

• Lymphoma

• Metastases

• Benign tumors with malignant potential: villous and adenomatous polyps, carcinoid

Complications of Surgery ( Fig. 3.25 )

• Immediate complications:

  • Anastomotic leak

  • Abscess

  • Gastric outlet obstruction (edema)

  • Bile reflux gastritis

  • Ileus

• Late complications:

  • Bowel dysmotility: dumping, postvagotomy hypotonia

  • Ulcer

  • Bowel obstruction: outlet obstruction, adhesions, stricture

  • Prolapse, intussusception

  • Gastric carcinoma (in 5% of patients 15 years after surgery), Billroth II > Billroth I

  • Metabolic effects: malabsorption

  • Afferent loop syndrome

  • Small pouch syndrome

Complications

• Narrowing/stenosis

  • Immediate postsurgical narrowing is common and often subsides

  • Stenosis (lumen <6 mm) at >6 weeks after surgery is rare. Weight loss can be dramatic.

• Anastomotic leak

  • Incidence of leaks after Roux-en-Y bypass surgery is 1%–6%. More common after laparoscopic than open surgery.

  • The leak is commonly at the gastrojejunal anastomosis or at the enteroenteric anastomosis (both are life threatening).

  • Contrast material outside the confines of the gastric pouch and anastomosis indicates a leak. Although leaks from the enteroenteric anastomosis are rapidly clinically evident and severe, they are usually not diagnosed radiographically.

  • Immediate surgical exploration is needed.

• Fistula

  • During surgery, the gastric pouch and remnant are surgically separated. Oral contrast should not directly enter the gastric remnant. The presence of oral contrast in the remnant thus indicates a gastro-gastric fistula.

  • Contrast may be seen in excluded stomach on SBFT by retrograde filling through the duodenum.

• Internal hernia: The most common herniation is the transmesenteric (or transmesocolonic) type, which occurs through the defect in the transverse mesocolon. The herniated bowel is usually the Roux limb itself with a varying amount of additional SB loops.

  • CT findings:

    • Abnormal position of distended SB loops anterior to the pancreas and above the transverse colon; obstruction

    • Inferior displacement of the transverse colon

    • Crowding, engorgement, and deviation of mesenteric vessels

    • The transition point is proximal to the jejunojejunostomy.

• Hernias may also occur in the SB mesenteric defect at the jejunojejunostomy site and in the space posterior to the Roux limb (Peterson type).

• Weight gain

  • Degradation of pouch restriction: very rapid passage of contrast through a patulous anastomosis degrades the restrictive properties of the laparoscopic Roux-en-Y gastric bypass, resulting in weight gain.

  • Gastrogastric fistula: although uncommon, a fistulous tract arising from the pouch may opacify the excluded stomach and is thought to be a result of patient overeating.

Complications

• Band placed too low in stomach

• Band not placed around stomach

• Band placed around esophagus, which is undesirable because sensation of satiety lacking and risk of perforation

• Slippage of the band with upward herniation of stomach (late complication).

Normal Appearance of SB by SBFT

• Luminal diameter

  • >3 cm is abnormal

• Fold thickness

  • Valvulae conniventes measure 1–2 mm; more prominent in jejunum than ileum

  • >3 mm is abnormal

• Wall thickness

  • Normal is 1–1.5 mm

• Secretions

  • There should normally be no appreciable fluid in SB.

  • Excess secretions cause dilution of barium column.

Computed Tomography

• Normal wall thickness: 1–1.5 mm

• Incomplete distention or luminal fluid may mimic abnormally thick wall; look for antidependent luminal gas collections to better assess wall thickness.

Imaging Features

• Dilatation of bowel loops

• Diluted barium (mixes with watery bowel content)

• Flocculated barium: barium aggregates into particles (mainly seen with older barium suspensions)

• Slow transit

• Segmentation of barium (lack of continuous column) rarely occurs with new agents

• Moulage pattern: featureless barium collection (rarely occurs with new agents)

• Hidebound pattern: valvulae thinner, closer together, wrinkled look

• Many of these features may no longer be seen with newer barium products.

Sprue

• Three entities:

  • Tropical sprue (unknown cause; responds to antibiotics)

  • Nontropical (adults; intolerance to gluten in wheat and other grains; HLA-DR3, IgA, IgM antibodies)

  • Celiac disease (children)

Imaging Features

• Dilatation of SB is the most typical finding (caliber increases with severity of disease).

• Nodular changes in duodenum (bubbly duodenum)

• Reversal of jejunal and ileal fold patterns: “The jejunum looks like the ileum, the ileum looks like the jejunum, and the duodenum looks like hell.”

• Segmentation

• Hypersecretion and mucosal atrophy cause the moulage sign (rare).

• Transient intussusception pattern (coiled spring) is typical.

• Increased secretions: flocculation with older barium suspensions

• Increased incidence of malignancy, aggressive lymphoma, carcinoma

Associated Disorders

• Dermatitis herpetiformis

• Selective IgA deficiency

• Hyposplenism

• Adenopathy

• Cavitary mesenteric LN syndrome

Complications

• Ulcerative jejunoileitis: several segments of bowel wall thickening with irregularity and ulceration strictures may follow

• Enteropathy: associated T-cell lymphoma

• Increased incidence of cancers of esophagus, pharynx, duodenum, and rectum

• Sprue, SBO, scleroderma (SOS): dilated, prolonged motility, normal folds

Clinical Findings

• Diarrhea

• Steatorrhea

• Histamine effects (flushing, tachycardia, pruritus, PUD)

Imaging Features

• SB

  • Irregular fold thickening

  • Diffuse small nodules

• Other

  • Sclerotic bone lesions

  • Hepatosplenomegaly

  • Peptic ulcers (increased hydrochloric acid [HCl] secretion)

Imaging Features

• Kidneys

  • Nephrotic syndrome

  • Renal insufficiency

  • Renal tubular acidosis

  • Renal vein thrombosis

• GI tract

  • Diffuse thickening of SB folds

  • Jejunization of ileum

  • SB dilatation

  • Multiple nodular filling defects, >2 mm

  • Hepatosplenomegaly

  • Macroglossia

  • Colonic pseudodiverticulosis (may be unilateral and large)

• Heart

  • Cardiomyopathy (restrictive)

  • Rhythm abnormalities

• Nervous system

  • Signs of dementia

  • Carpal tunnel syndrome

  • Peripheral neuropathy

Imaging Features

• Diffuse nodular thickening of folds in jejunum and ileum caused by dilated lymphatics and hypoalbuminemic edema; mesenteric adenopathy on CT

• Dilution of contrast material as a result of hypersecretion

• Lymphographic studies

  • Hypoplastic lymphatics of lower extremity

  • Tortuous thoracic duct

  • Hypoplastic LNs

Imaging Features

• Classic finding: SB loops, which are too narrow, and featureless margins (ribbon bowel)

• Luminal narrowing is due to edema of the bowel wall.

• Flattening of mucosal folds (edema)

• Prolonged coating of barium for days

Imaging Features

• SB

  • Dilation of bowel loops with hypomotility is a key feature.

  • Mucosal folds are tight and closer together (fibrosis): hidebound appearance.

  • Pseudosacculations along antimesenteric border, may involve both small and large bowel

  • Segmentation, fragmentation, hypersecretion are absent.

• Other

  • Dilated dysmotile esophagus, esophagitis, incompetent LES, reflux, stricture

  • Dilated duodenum and colon (pseudo­obstruction)

  • Pneumatosis cystoids coli (steroid therapy)

  • Pulmonary interstitial fibrosis

  • Acroosteolysis

  • Soft tissue calcification

Clinical Findings

• Middle-aged men, United States, Northern Europe

• Diarrhea, steatorrhea

• Immune defects

Imaging Features

• 1–2-mm diffuse micronodules in jejunum

• No dilatation or increased secretions

• Nodal masses in mesentery (echogenic by US); nodes have low CT density

• Sacroiliitis

Types

• Enteroenteric: SB → SB

• Enterocolonic: SB → colon

• Enterocutaneous: SB → skin

• Enterovesical: SB → bladder

• Enterovaginal: SB → vagina

Radiographic Workup

• Fistulogram (enterocutaneous fistula): injection of water-soluble contrast material through small catheter inserted into fistula

• UGI and SBFT

• Barium enema

Therapy

• Total parenteral nutrition to achieve “bowel rest”

• Postoperative fistulas usually heal spontaneously with conservative measures.

• Fistulas in active Crohn disease usually require excision of diseased bowel.

• Cyclosporine and other immunosuppressants have been used to heal fistulas in Crohn disease; more recently monoclonal antibody (infliximab) has been used.

Cryptosporidiosis

Cryptosporidium species are protozoa that frequently cause enteritis in AIDS patients but rarely in immunocompetent patients. Diagnosis is made by examination of stool or duodenal aspirate.

Imaging Features

• Thickened SB folds

• Dilatation of SB

Ascariasis ( Fig. 3.29 )

Infection with Ascaris lumbricoides (roundworm, 15–35 cm long) is the most common parasitic infection worldwide.

Imaging Features

• GI tract

  • Jejunum > ileum, duodenum, stomach

  • Worms visible on SBFT as longitudinal filling defects

  • Enteric canal of worm is filled with barium

  • Worms may cluster: “bolus of worm”

  • Mechanical SBO

  • Other complications: perforation, volvulus

• Biliary tract

  • Intermittent biliary obstruction

  • Granulomatous stricture of bile duct (rare)

  • Oriental cholangiohepatitis

Imaging Features

• Mass lesion in SB: filling defect

• Strong desmoplastic reaction causes angulation, kinking of bowel loops (tethered appearance), mesenteric venous congestion

• Mesenteric mass on CT with spokewheel pattern is virtually pathognomonic; the only other disease that causes this appearance is retractile mesenteritis (very rare).

• Stippled calcification in mesenteric mass

• Obstruction secondary to desmoplastic reaction

• Very vascular tumors (tumor blush at angiography, very hyperintense on T2-weighted [T2W] images)

• Liver metastases (arterial phase indicated)

Complications

• Ischemia with mesenteric venous compromise

• Hemorrhage

• Malignant degeneration: gastric and appendiceal tumors rarely metastasize; SB tumors metastasize commonly.

Patient Preparation

• Clear liquid diet day before examination

• Magnesium citrate, 300 mL, afternoon before examination

• 50 mL castor oil evening before examination

• Cleansing enema morning of examination

Single-Contrast Technique

• 1

  Insert tube with patient in lateral position.

• 2

  Decide if need to inflate balloon for retention; if so, inflate under fluoroscopic control, being sure that balloon is in the rectum.

• 3

  Fluoroscopy as the barium goes in.

• 4

  Patient in supine position (as opposed to double-contrast study). Instill barium just beyond sigmoid colon. Take AP and two oblique spot radiographs of sigmoid.

• 5

  Try to follow head of column fluoroscopically.

• 6

  Take spot views of both splenic flexure and hepatic flexure.

• 7

  Spot cecum and terminal ileum. If a filling defect is encountered, palpate to see if it is sessile or floating.

• 8

  Obtain overhead views and postevacuation radiographs.

Double-Contrast Technique

• 1

  Patient is in lateral position. Insert tube.

• 2

  Patient supine: administer glucagon IV. Turn patient prone: this helps barium flow to the descending colon, decreases pooling in the rectum and sigmoid, and thereby is less uncomfortable. Instill barium beyond the splenic flexure. Stand patient up, bag to the floor, and let barium drain.

• 3

  Place patient in horizontal prone position. Start slow inflation with air and rotate patient toward you into a supine position. Take spot views of the sigmoid in different obliquities (take spots of any air-filled loop). When patient is supine, check to see if barium has already coated the ascending colon.

• 4

  Stand patient up to facilitate coating of ascending colon. Drain as much barium as possible through rectal tube. Insufflate more air.

• 5

  Spot views of splenic and hepatic flexure in upright position. Take spots in slightly different obliquities of both flexures.

• 6

  Patient prone; put table down. Take spot views of the cecum and sigmoid.

• 7

  Obtain overhead views:

  • AP, PA

  • Prone, cross-table lateral

  • Decubitus

  • Postevacuation radiographs

Contraindications to Barium Enema (BE)

• Suspected colonic perforation (use water-soluble iodinated contrast)

• Patients at risk for intraperitoneal leakage (use Gastrografin):

  • Severe colitis

  • Toxic megacolon (TMC)

  • Recent deep biopsy

• If colonoscopy needs to follow enema; use water-soluble iodinated contrast

• Severe recent disease: myocardial infarction, cerebrovascular accident (CVA)

Complications of Barium Enema

• Perforation (incidence 1 : 5000), typically caused by overinflation or traumatic insertion of balloon or fragile colonic walls

• Appearance of gas in portal venous system in patients with IBD (no significant ill effects)

• Allergy to latex tips

Glucagon

Glucagon is a 29–amino acid peptide produced in A cells of the pancreas.

Physiologically, the main stimulus for glucagon release is hunger (hypoglycemia).

Effects:

• Antagonist to insulin (increases blood glucose)

• Relaxation of smooth muscle cells

• Relaxation of gallbladder (GB) sphincter and sphincter of Oddi; increased bile flow

Glucagon is a useful adjunct (0.1–1 mg IV) to barium enema (BE) or whenever smooth muscle spasm is suspected of producing a “pseudostenotic lesion.” Thus it can be used in evaluation of the esophagus, stomach, duodenum, small intestine, common bile duct (CBD), and colon.

Contraindications include:

• Pheochromocytoma

• Insulinoma

• Glaucoma

Clinical Findings

• Asymptomatic

• Diarrhea

• Pain

• Hemorrhage

Location ( Fig. 3.30 )

• Rectum and sigmoid, 60%

• Descending colon, 15%

• Transverse colon, 15%

• Ascending colon, 10%

Differentiation of Benign and Malignant Polyps

• Histologic differentiation of polyps is invariably difficult radiographically, so the majority of lesions require endoscopic sampling.

Imaging Features

• Stalked polyp

• Sessile but <5 mm

Imaging Features

• Filiform polyps: thin, short, branching structures

Familial Polyposis

• Most common intestinal polyposis syndrome (incidence 1 : 8000)

• Screening of family members of familial polyposis patients should start at puberty: malignant degeneration by 40 years (treatment: prophylactic total proctocolectomy)

• Usually >100 polyps

• Polyps may be sessile or stalked.

• Familial adenomatous polyposis syndrome is a common umbrella name under which Gardner and familial polyposis syndromes are included.

Gardner Syndrome

• Polyposis: colon 100%, duodenum 90%, other bowel segments <10%

• Hamartomas of stomach

• Soft tissue tumors: inclusion cysts, desmoids (30%), fibrosis

• Osteoma in calvarium, mandible, sinuses

• Entrapment of cranial nerves

• Malignant transformation in 100% if untreated

• SB and pancreaticoduodenal malignancies

• Total colectomy recommended

Peutz-Jeghers Syndrome

• Second most common intestinal polyposis

• Autosomal dominant

• Hamartomas throughout GI tract except the esophagus

• Mucocutaneous pigmentations (buccal mucosa, palm, sole)

• Polyps have virtually no malignant potential.

• Slightly increased risk of stomach, duodenal, and ovarian cancer; benign neoplasm of testes, thyroid, and GU system

Juvenile Polyposis

• Usually large polyps in rectum

• Usually single; 80% are located in the rectosigmoid.

• Present in children with bleeding, prolapse, or obstruction

Cowden Disease

• Multiple hamartoma syndrome

• Mucocutaneous pigmentations (buccal mucosa, palm, sole)

• Most common in rectosigmoid with lesions also present in esophagus

• Mucocutaneous lesions → facial papules, oral mucosal papillomatosis, acral keratoses, sclerotic fibromas

• Thyroid gland abnormalities: goiter, adenomas

• Breast cancer (ductal), bilateral in 30%

• Uterine and cervical carcinomas

• Transitional cell carcinoma (TCC) of bladder and ureter

Turcot Syndrome

• Glioma polyposis syndrome

• Colonic adenomas with CNS gliomas and medulloblastomas

Location

• Rectum, 35%

• Sigmoid, 25%

• Descending colon, 10%

• Ascending colon, 10%

• Transverse colon, 10%

• Cecum, 10%

Imaging Features ( Fig. 3.32 )

• Polypoid

• Ulcerative

• Annular constricting (apple core); <5 cm long

• Plaque-like (e.g., cloacogenic tumor at anorectal junction)

• Scirrhous carcinoma (rare): long (>5 cm) circumferential spread

Complications

• Obstruction

• Intussusception (in polypoid lesions), rare

• Local perforation (simulates diverticulitis)

• Local tumor recurrence

• Peritoneal spread

Staging ( Fig. 3.33 )

• Dukes staging system

  • Dukes A: Limited to bowel wall, 15%; 93% 5-year survival

  • Dukes B: Extension into serosa or mesenteric fat, 35%; 77% 5-year survival

  • Dukes C: LN metastases, 35%; 48% 5-year survival

  • Dukes D: Distant metastases (15%): liver, hydronephrosis, peritoneal cavity, adrenal; 7% 5-year survival

Tumor-Node-Metastases (TNM) Classification

• Tx: No description of the tumor's extent is possible.

• Tis: The cancer is in the earliest stage. It has not grown beyond the mucosa (inner layer) of the colon or rectum. This stage is also known as carcinoma in situ or intramucosal carcinoma.

• T1: Cancer has grown through the mucosa and extends into the submucosa.

• T2: Cancer has grown through the submucosa, and extends into the muscularis propria.

• T3: Cancer has grown completely through the muscularis propria into the subserosa but not to any neighboring organs or tissues.

• T4: Cancer has spread completely through the wall of the colon or rectum into nearby tissues or organs.

• Nx: No description of LN involvement is possible because of incomplete information.

• N0: No LN involvement

• N1: Cancer cells found in 1–3 nearby LNs.

• N2: Cancer cells found in 4 or more nearby LNs.

• Mx: No description of distant spread is possible because of incomplete information.

• M0: No distant spread is seen.

• M1: Distant spread is present.

Diagnostic Accuracy

• Detection of LN metastases

  • CT: 50%–70%

  • MRI currently < CT

• Detection of liver metastases

  • Contrast-enhanced CT: 60%–70%

  • MRI: 70%–80%

Causes

• Idiopathic IBD

  • UC

  • Crohn disease

  • Behçet disease

• Infectious colitis

• Ischemic colitis

• Iatrogenic

  • Radiation

  • Chemotherapy

Imaging Features

The imaging features of bowel inflammation (any cause) depend mainly on the location of the process:

• Mucosal inflammation

  • Ulceration

    • Shallow: granularity of mucosa, aphthoid

    • Deeper: flask like collections of barium: collar button

  • Edema

    • Displacement of barium: translucent halo around central ulcer

  • Spasm

    • Localized persistent contraction

    • Narrowing of bowel lumen

• Submucosal inflammation

  • Ulcers (deeper linear than in mucosal inflammation): cobblestone appearance

  • Bowel wall thickening

    • CT: wall thickened (>3 mm with lumen distended)

    • Halo: fatty (chronic), gray (subacute or chronic), white (acute) with enhancement

• Subserosal mesenteric inflammation

  • Stranding in surrounding fat

  • Inflammatory mass

  • Fistula

  • Creeping fat: excessive fat deposited around serosal surface (Crohn disease)

Imaging Features ( Fig. 3.35 )

• Types of lesions

  • Thickening of folds (edema)

  • Nodular pattern (submucosal edema and inflammation)

  • String sign: tubular narrowing of intestinal lumen (edema, spasm, scarring depending on chronicity)

  • Omega sign: asymmetric wall involvement results in contracture and C-shaped loop on SB series

  • Ram horn sign: loss of antral fornices with progressive narrowing from antrum to pylorus

  • Ulcerations:

    • Aphthoid ulcers are early lesions and correspond to mucosal erosions (pinpoint ulcer in edematous mound up to 3 mm in diameter and 2 mm in depth).

    • Ulcers are irregularly scattered throughout GI tract and are interspersed with normal mucosa.

    • Ulcerations grow and fuse with each other in linear fashion and, with intervening edematous mucosa, produce an ulceronodular pattern (“cobblestone” appearance).

  • Filiform polyposis: thin, elongated, branching mucosal lesions; represents proliferative sequelae of mucosa adjacent to denuded surface

  • Sinus tracts and fistulas originate in fissures or deep ulcers; characteristic of Crohn disease at advanced stages.

  • Fatty thickening along mesenteric border (creeping fat) and paracolonic lymphadenopathy separate bowel loops.

  • Fibrosis and scarring may result in:

    • Pseudodiverticula (fibrosis develops eccentrically)

    • Rigid, featureless bowel

    • Strictures and obstruction

    • Foreshortening of bowel

• Spatial arrangement of lesions

  • Transitional zones are typical; they occur between involved bowel loops and normal bowel.

  • Skip lesions are typical: discontinuous involvement of bowel

  • Lesions appear preferentially at mesenteric side of intestine.

Mural and Extramural Changes (CT Findings)

• Primary intestinal findings

  • Bowel wall thickening

    • Normally <3 mm if well distended

    • Mean diameter in Crohn disease: 10 mm

    • If >10 mm, include pseudomembranous, ischemic, or CMV colitis in DDX.

  • Circumferential submucosal low attenuation surrounded by higher outer attenuation: halo sign

  • Inner and outer layers surrounding low-attenuation middle layer: target sign; middle layer of fat density; chronic, middle layer of water density

• Peribowel inflammation (“dirty fat,” “ground glass”)

• Mesentery

  • Fat accumulates on serosal surfaces (“creeping fat”)

  • Inflamed mesentery fat (stranding, “misty”)

  • Adenopathy in SB mesentery common

  • Comb sign: vasa recta stretched out along one wall of colon

• Extraintestinal findings

  • Gallstones

  • Osseous complications (may cause pain)

    • Spondylitis

    • Sacroiliitis

    • Steroid complications: osteomyelitis, osteoporosis, avascular necrosis

  • Renal stones, 7%

Complications ( Fig. 3.36 )

• Recurrence of disease after surgery (in contrast to UC, in which proctocolectomy is curative)

• Increased incidence of malignancies:

  • GI tract tumors

  • Lymphoma

• TMC

• Fistulas

• Abscess formation

Associated Findings

• Joints, 25%: arthritis, arthralgia, ankylosing spondylitis

• Liver, 10%: sclerosing cholangitis, chronic active hepatitis, cholangiocarcinoma

• Skin: pyoderma gangrenosum, erythema nodosum

• Uveitis, episcleritis

Imaging Features

• Ahaustral, foreshortened colon (lead pipe)

• Granular mucosa, shallow confluent ulcerations

• Polyps:

  • Pseudopolyps

  • Filiform polyps (regenerative mucosa, small thin, branching polyps)

• Spread:

  • Disease first and worst in rectum

  • Continuous spread from distal to proximal colon

  • Circumferential bowel involvement

  • Backwash ileitis: only short segment of terminal ileum unlike Crohn disease, gaping ileocecal valve

• Atypical imaging features:

  • Atypical pattern of distribution: sparing of rectum (which may be healing), 5%

  • Crohn-like findings: discontinuous disease in 5%–10% of patients

• Mural and extramural changes (CT findings):

  • Bowel wall thickening less than Crohn disease

  • Distribution from rectum continuously proximal

  • If pancolitis, terminal ileum may be affected for a very short length.

  • Superimposed carcinoma: mass lesion or thick wall stricture

  • Excessive fat surrounding rectosigmoid (creeping fat)

  • Local LN enlargement; common in SB mesentery, infrequently the retroperitoneum

Complications

• TMC: ahaustral transverse colon: >6 cm with pseudopolyps on kidney, urethra, bladder (KUB; can complicate most colitides)

• Strictures, obstruction: benign or malignant. Any stricture is suggestive of malignancy.

• Malignancy (5–30-fold higher risk than general population)

• Annual incidence of 10% after the first decade

• Multiple in 25% of cases

• Often flat and scirrhous

Cause

• Primary; obstruction of anal gland, stasis, infection, fistula

• Secondary; iatrogenic (surgery), Crohn, infection, malignancy

Types

• Intersphincteric (common)

• Transsphincteric (common)

• Suprasphincteric

• Extrasphincteric (uncommon and seen in patients with multiple operations)

Imaging Features

• MRI is best technique for assessment

• Describe and classify type of fistula

• Distance of mucosal defect to perianal skin

• Secondary findings; abscesses, bowel wall abnormalities, reactive nodes

Treatment

• Fistulotomy

• Fistulectomy

• Sphincter-saving fistulectomy

• Seton fistulotomy

Intestinal Manifestations

• Ulcers

• Strictures

• Fistulas

Extraintestinal Manifestations

• Oral, genital, skin ulcers

• Uveitis

• Aneurysms

• Arthritis

Imaging Features

• Superficial (aphthoid) or deep ulcers

• Thick wall: >10 mm

• Localized distribution in cecum, terminal ileum, or universal colitis

• Radiographically may be indistinguishable from pseudomembranous colitis

Clinical Findings

• RLQ pain, 50%

• Diarrhea, 40%

• Peritoneal signs in perforation