GIT ANOMALIES

Dr Varun BansalDept of Radio-Diagnosis

• Most Congenital Anomalies of the Gastrointestinal Tractmanifest early after birth while some may not present till late childhood or adulthood.

• Various modalities used are:

1. Plain radiography2. Ultrasound3. Computed tomography 4. Magnetic Resonance Imaging5. Radionucleotide imaging

Introduction

Classification of developmental anomalies of GIT

StructuralAttributed to embryologic maldevelopment• Esophageal atresia with or without fistula• Antro-pyloric atresia• Antral diaphragm• Duodenal atresia• Duodenal stenosis• Midgut malrotation with peritoneal bands• Duplication or mesenteric cyst• Anorectal atresia

Attributed to in-utero vascular (ischemic) complication

• Jejuno-ileal atresia• Colonic atresia or stenosis• Complicated meconium ileus

Functional• Meconium plug syndrome and its variants• Megacystis-microcolon-intestinal hypoperistalsis

Structural and Functional Combined• Hypertrophic pyloric stenosis• Midgut volvulus • Uncomplicated meconium ileus• Colonic aganglionosis

Esophageal Atresia Tracheo-Esophageal fistula

ANTENATAL CLUES : Esophageal atresia• Presence of polyhydramnios,• Reduced intraluminal liquid in the fetal gut • Inability to detect the fetal stomach on prenatal

ultrasound

CHEST RADIOGRAPH: • proximal esophageal pouch distended with air• dilated proximal esophageal pouch with round distal

margin and coiled nasogastric tube within is diagnostic• (on lateral): considerable anterior bowing and

narrowing of the trachea by the dilated blind esophageal pouch

• air in the stomach and the small bowel esophageal atresia with a distal tracheo esophageal fistula.

• Absence eliminates the possibility of a distal fistula.

Frontal radiograph of

chest and abdomen showing a

catheter in the proximal pouch. The abdomen is

gasless. (B) Lateral film

shows the tip of the nasogastric tube at the level

of 4th dorsal vertebra

CONTRAST STUDIES: Should be avoided, fear of aspiration• isotonic nonionic contrast medium• Though H-type fistulas can be at any level, most are at the

thoracic inlet, between C7 and T2 vertebral bodies • best way to demonstrate H-type: Others can be bronchoscopy

and endoscopy• CT is an excellent non invasive investigation.• EARLY COMPLICATIONS (i) leakage at the anastomotic site (ii)

esophageal stricture and (iii) recurrent fistula.LATE COMPLICATIONS are dysmotility, gastroesophageal reflux, tracheomalacia, rib fusion and scolosis

• TYPE A—Esophageal atresia without fistula (7.8%)• TYPE B—Esophageal atresia with proximal fistula (0.8%)• TYPE C—Esophageal atresia with distal fistula (85.8%)• TYPE D—Esophageal atresia with fistula in both the

pouches (1.4%)• TYPE E—H-type fistula without atresia (4.2%)The plain radiographs for types A and B are similar as in case for types C and D

H-type tracheoesophageal fistula. The contrast studydemonstrates the superiorly angulated fistula (arrow) fromthe oesophagus to the trachea

Microgastria

• fetal rotation of the stomach fails to occur• accompanied by other congenital anomalies such as

malrotation, asplenia, renal, limb, vertebral and cardiac anomalies (VACTERL syndrome).• Prenatal ultrasound mimic esophageal atresia due to

failure to visualize a distended stomach.• UPPER GI STUDY:• shows a small tubular stomach in the midline.• esophagus is dilated and appears to take over the storage

function of the small capacity stomach. • gastroesophageal junction is incompetent and GER is present.• Associated esophageal dysmotility, secondary to its massive

dilatation.

Gastric obstructionCAUSES :• 1. Gastric atresia• 2. Pyloric stenosis• 3. Pyloric/ prepyloric membrane/ Antral web.

GASTRIC ATRESIA -- THREE TYPES: a) Complete atresia with no connection between the stomach

and duodenum, b) Complete atresia with a fibrous band connecting the

stomach and duodenum, c) Gastric membrane or diaphragmON CHEST RADIOGRAPH:1. “single bubble appearance” 2. marked dilatation of the stomach, proximal to the

obstruction 3. absence of gas in the small bowel and colon

Pyloric Stenosis or Prepyloric Membrane orAntral Web

• RADIOGRAPH:• the stomach is dilated with varying degrees of distal air, • the extent of which depends on the degree of obstruction. • In incomplete obstruction, webs more common than

stenosis.• UGI BARIUM STUDIES:• a web is seen as a thin, 2-3 mm, linear circumferential

filling defect traversing the barium column • producing a reduction in the antral lumen, • normal pyloric canal.

• ULTRASOUND:• membrane may be visible if the stomach is filled with clear

fluid • WEB echogenic band extending centrally from the lesser

and greater curvatures in the prepyloric region. • A mucus strand may be mistaken for an antral membrane.

• ENDOSCOPY:• definitive diagnosis of antral web can be made.

Congenital Hypertrophic Pyloric Stenosis

ON ULTRASONOGRAPHY:• thickened echo-poor pyloric muscle and an elongated pyloric canal.• two curved bundles of mixed but generally low reflectivity• “doughnut appearance”, representing the reflective central mucosa

and submucosa surrounded by echopoor muscle• pyloric canal length greater than 15 mm, • muscle thickness greater than 3.0 mm • transverse serosa-to-serosa diameter greater than 15 mm is consistent

with HPS• < 2 mm thick unequivocally normal.• 2 - 3 mm abnormal but not specifically diagnostic for pyloric stenosis

• Diagnosis made on appropriate history and palpation of an ‘olive’ mass in the subhepatic region of an infant.

• Antral peristaltic waves can also be observed.

• Longitudinal ultrasound image showing an elongated thickened pylorus seen as two curved bundles of low reflectivity (m). The mucosal echoes are seen as central bright lines. gb – gallbladder shows sludge within. Minimal fluid is present around the stomach. (B) Transverse section shows the muscle thickness as an echo poor rim – “Bull’s eye” sign. serosa to serosa measures 15 mm

“SHOULDER SIGN” – refers to an indentation upon the gastric antrum produced by hypertrophy of the pyloric muscle• “DOUBLE TRACT SIGN” – this refers to fluid, trapped in the mucosal folds in the center of an elongated pyloric canal seen as two sonolucent streaks in the center• “NIPPLE SIGN” is produced due to the evagination of redundant pyloric mucosa into the distended portion of the antrum.

BARIUM STUDY: if usg - inconclusive or gastro-oesophageal

reflux • hypertrophied muscle mass causes elongation and narrowing of pyloric canal (‘STRING SIGN’) • a bulge in the distal antrum with streak of barium pointing towards pyloric channel (‘BEAK SIGN’).•The barium may outline crowded mucosal folds asparallel lines (‘DOUBLE/TRIPLE TRACK SIGN’)

Duodenal AtresiaINTRINSIC: Duodenal atresia, Duodenal stenosis, Duodenal web or diaphragm EXTRINSIC: Ladd’s bands, Midgut volvulus with malrotation, Annular pancreas, Duplication, Preduodenal portal vein

ABDOMINAL RADIOGRAPH: (usually diagnostic) 1. Air is present in the stomach and

proximal duodenum but none distally2. typical “double-bubble sign” represents

air, or air and fluid filled distended stomach and duodenal bulb

Further radiological study preoperative diagnosis distinguish between a cause of partial obstruction - duodenal stenosis from complete obstruction midgut volvulus.

• UGI STUDY:• duodenal stenosis appears as dilatation of the duodenum proximal

to the point of obstruction with abrupt calibre change

DOUDENAL WEB:• UGIE:

• diagnostic appearance thin, convex, curvilinear defect extending for a variable distance across the lumen of the duodenum.

• “wind sock” appearance seen in an adult or older child, intraluminal duodenal diverticulum, not seen in newborns.

ANNULAR PANCREAS:• RADIOGRAPHS: normal. MRI:• UPPER GI STUDIES:

a persistent waist is seen, partially obstructing the second part of duodenum.

Normal Physiology of Rotation.

STAGES OF INTESTINAL ROTATION: (A), the duodenum has rotated 90 counter clockwise to lie to the right of the superior mesenteric artery. The distal large bowel also rotates 90 counter clockwise. (B), the duodenum has rotated another 90 counter clockwise, In (C) the duodenum has rotated its final 90 counter clockwise with the duodenojejunal flexure lying to the left of the midline. The cecum continues to rotate . In (D), the normally rotated bowel is depicted.

• NONROTATION –• small bowel right side and colon left side. • demonstrated incidentally on barium studies in older children or adults• bowel is not very mobile and • volvulus is not a common complication

• MALROTATION – • final position between normal and complete nonrotation. • shortened mesenteric root - narrow rather than a broad base that has a

tendency to twist on its axis• bowel obstruction, lead to occlusion of the mesenteric vessels if twist of

vessels• twist of malfixed intestines around the short mesentery midgut

volvulus. • aberrant peritoneal bands (Ladd’s bands) (extend from the

malpositioned cecum across the duodenum and attach to the hilum of the liver, posterior peritoneum or abdominal wall)

• REVERSED INTESTINAL ROTATION –• hepatic flexure and left transverse colon posterior in position. • colon lie behind the descending duodenum and the superior mesenteric

artery• cecum is usually malrotated and medially placed and the small bowel is

more right-sided than normal. Obstructing bands & midgut volvulus

• PLAIN RADIOGRAPHS:• feature of duodenal obstruction due to partially obstructing Ladd’s bands. • duodenal bulb dilatation is less than that seen with duodenal atresia• distal bowel obstruction (in case of volvulus). • Bowel-wall thickening and pneumatosis volvulus-induced ischemia. • fluid-filled bowel loops associated with volvulus simulate an abdominal

mass• normal abdominal film (only in nonrotation)

• UPPER GASTROINTESTINAL BARIUM :• to document the location of ligament of Treitz and to evaluate for

duodenal obstruction. • duodenojejunal junction is located lower and to the right of normal. • on lateral views it is seen to lie behind the level of the stomach, with the

fourth part of the duodenum superimposed on the second part of duodenum (lost in case of malrotation)

• abnormal position of the duodenojejunal flexure may be the only indication

• complete obstruction a beaked tapering of the obstructed duodenum• pathognomonic “corkscrew pattern” of the twisted duodenum and

jejunum clockwise twisting around the superior mesenteric artery

• ULTRASOUND:• distended proximal duodenum with a tapered end in front of the

spine is consistent• peritoneal fluid and edematous bowel loops on the right. • UGI series is mandatory

• COLOR DOPPLER US:• demonstrates ‘whirlpool’ sign clockwise spiralling of the

mesentery and superior mesenteric vein around the superior mesenteric artery.

• Inversion of the mesenteric vessels or the “SMV rotation sign” (not sensitive) also in situs inversus & abdominal masses.

• CT : (midgut volvulus) • `whirl’ sign of small-bowel loops revolved around the SMA• dilated, fluid-filled, obstructed stomach and proximal duodenum• thick-walled loops of ischemic right-sided small bowel loops with

potential pneumatosis intestinalis and mesenteric edema• free intraperitoneal fluid.

BARIUM MEAL FOLLOW THROUGH STUDY (A) jejunal loops on the right side of the abdomen (B) colon and cecum on the left side, with the ileum seen crossing the midline from right to left – Non-rotation

MIDGUT VOLVULUS. Narrow mesenteric attachment of nonrotation (A) or incomplete rotation

(B) may lead to midgut volvulus (C)

LADD’S BANDS causing duodenal compression in patients with malrotation. The cecum is left sided (A) and mid-line (B) in position and has dense peritoneal bands crossing over the duodenum

MIDGUT MALROTATION WITH LADD’S BANDS: Barium study shows distended proximal duodenum with tapering at the level of obstruction indicative of extrinsic compression. The small intestine, distal to the usual site of the ligament of Treitz lies below the duodenum and to the right

• Upper GI barium study in two different patients showing classic “corkscrew” appearance of the duodenum in MIDGUT VOLVULUS

• Axial CECT of the abdomen showing characteristic “whirlpool” sign of clockwise twisting of the SMV and mesentery around the SMA

Small Bowel Atresia

• TYPE 1 —Membranous or web-like atresia, composed of mucosal and submucosal elements with no interruption of the muscularis.

• TYPE 2 —Atresia with a solid fibrous cord connecting the atretic bowel ends, but the mesentery is intact. All the three layers of the intestinal wall are interrupted.

• TYPE 3 —Complete absence of a segment of bowel (total atresia) as well as a portion of the mesentery (V-shaped defect in the mesentry)

• TYPE 4 —The familial form of multiple atresias• UNUSUAL FORMS OF ATRESIA : “Apple peel” or “Christmas tree”

atresia

• PLAIN RADIOGRAPH:• findings of small-bowel obstruction. • Site number & location of gas-filled loops of bowel. • Proximal jejunal atresia triple bubble sign, • more distal atresia uniform dilatation & air-fluid levels.• proximal loop just proximal to the site of atresia is distended• if perforation meconium peritonitis .• linear calcification under the free edge of the liverAssociation of meconium peritonitis with small bowel obstruction is virtually diagnostic of small bowel atresia.

• SONOGRAPHY: • Ileal atresia the bowel contents are echopoor • Meconium ileus dilated bowel loops are filled with echogenic

material• CONTRAST ENEMA:

• further evaluation for low bowel obstruction to distinguish between a large or distal small bowel obstruction

• Most common causes of neonatal distal small bowel obstruction are ileal atresia and meconium ileus

Click icon to add picture • In cases of partial

obstruction little amount of distal gas is usually present.

• In isolated proximal atresia of the duodenum or jejunum, the colon is of normal size- normal caliber colon

• In ileal atresia, the colon has a normal location but the caliber is reduced (functional micro colon).

Small bowel atresia: Plain radiograph demonstrates multiple dilated bowel loops and fluid levels. Peritoneal calcifications are seen as a result of meconium peritonitis.

JEJUNAL ATRESIA. (a) Supine

radiograph in a neonate with associated

esophageal atresia shows three dilated loops of bowel (b) upright radiograph

obtained in a different patient shown air-fluid levels in the

stomach and the first part of the small bowel. No

distal gas is seen.

Ileal Atresia

( a ) Upright radiograph shown multiple air-fuild levels occupying the entire abdominal cavity. ( b) Image from a barium enema study shows numerous dilated, air-filled loops of bowel and a small, unused colon (functional

microcolon).

Meconium ileus• mimic of small bowel atresia clinically and on plain films• ABDOMINAL RADIOGRAPH:• distal bowel obstructive pattern with air-fluid levels. • loops may vary in size, (finding seen less often in atresia)• bubbly appearance in the right lower quadrant air mixes with the

viscid meconium • “soap bubble appearance” is not specific also seen ileal atresia,

colonic atresia, aganglionosis of the terminal ileum and meconium plug syndrome.

• fewer air-fluid levels than patients with small-bowel atresias. • Meconium peritonitis <-> peritoneal calcifications.• localized perforation forms a meconium pseudocyst peripheral

curvilinear calcifications• ULTRASOUND:• can detect abnormal bowel dilatation • echogenic bowel contents in infants with meconium ileus. • complications of meconium peritonitis or pseudocyst which is seen

as echogenic material lying outside the bowel loops, with or without associated calcification.

(a) Abdominal scout radiograph shown marked distention of the small bowel and a “soap bubble”appearance in the right side of the abdomen a finding suggestive of mottled air and feces. (b) US

image shown dilated, fluid-filled intestinal loops containing echogenic material ( calcified meconium.

Water soluble contrast enema showing a microcolon. Filling defects due to meconium are seen in colon and distal ileum

• CONTRAST ENEMA:• demonstrates a

microcolon with inspissated meconium pellets identified in the collapsed distal ileum with dilated small bowel proximal to the obstruction

Megacystis-microcolon-intestinalHypoperistalsis Syndrome (Berdon Syndrome)

• pseudoatresia. • functional small bowel obstruction with a

microcolon, malrotation and a large unobstructed bladder

• UPPER GI CONTRAST STUDY:• hypomotility of small bowel with retrograde

peristalsis.

Meckel’s Diverticulum

• evaluation is difficult • Routine and special radiological studies such as

plain abdominal radiograph, barium meal follow through, arteriography and computed tomography are often non-diagnostic & of limited diagnostic value. • seldom recognized on a small bowel follow-

through study no significant hold-up & small residue in small neck. • 99MTC (TECHNETIUM -99M

PERTECHNETATE) SCANNING:• Done in suspected symptomatic patients.

Enteric Duplication Cyst

• uncommon & occur anywhere in the gastrointestinal tract.

• distal ileum (35%) > distal esophagus (20%) > stomach (9%) > duodenum > jejunum.

• PLAIN RADIOGRAPHS:• demonstrate a mass lesion in chest (esophageal

duplication) • bowel gas pattern may suggest an obstruction,

particularly with duodenal or ileal duplications• mural calcifications

• CONTRAST STUDIES:• filled with barium suspension • May not demonstrated in this manner. • reveals extrinsic compression of the bowel or an

obstruction

Barium study shows extrinsic impression on the body of the stomach with effacement of the mucosa in AP and lateral views in a case of

gastric duplication

• ULTRASONOGRAPHY:• Well defined, unilocular anechoic mass with good through

transmission• Rarely the contents are reflective or contain septations

secondary to hemorrhage or inspissated material within the lumen.

• highly reflective mucosa and a surrounding echo poor muscular wall identified in the dependent portion of the cyst.

• double layered appearance (“gut wall signature”) is specific & exclude other cystic masses - mesenteric or omental cyst, choledochal cyst, ovarian cyst, pancreatic pseudocyst or abscess

• RADIONUCLIDE STUDIES:• useful in patients where the enteric duplications have gastric

mucosa. • Free pertechnetate is taken up and secreted by gastric mucosa,

• CT & MRI: • useful in further characterizing the nature when the diagnosis is

unclear, • seen as well-marginated, smooth walled masses of fluid

attenuation/signal not showing any contrast enhancement.

CECT images of esophageal and gastric duplications of the two patients of the showing sharply marginated, non-enhancing, homogeneous mass of water attenuation in the (A) posterior mediastinum and (B) along the greater curvature of stomach.

Mesenteric Cyst (Lymphangioma)

• congenital malformation arising due to sequestration of lymphatic vessels.• seen in the mesentery and less often in omentum and

retroperitoneum. • SONOGRAPHY:• thin-walled unilocular or multilocular cystic lesion • useful to demonstrate the thin septations which may not be

well seen on CT.• CT and MRI:• demonstrate variable characteristics of the cyst contents

(usually water-to fat) depending upon whether fluid is chylous, infected or haemorrhagic.

• RARELY, A MESENTERIC LYMPHANGIOMA MAY CONTAIN CALCIFICATION MIMICKING A MESENTERIC TERATOMA

Colonic obstruction

• ANATOMICAL TYPE:• atresia of the colon, • anorectal atresia, and

• ANATOMICAL TYPE WITH A FUNCTIONAL ELEMENT: • aganglionosis or Hirschsprung’s disease.

• FUNCTIONAL OBSTRUCTION:• meconium plug, • neonatal small left colon syndrome

Colonic Atresia• TYPE I: represents a diaphragmatic occlusion,

• TYPE II: represents a complete atresia with a blind, solid cord extending between the two ends of atretic segment;

• TYPE III: represents a complete atresia with complete separation and an associated V-shaped mesenteric defect.

• PRENATAL SONOGRAPHY: • demonstrate dilatation of the colon proximal to the atresia.

• PLAIN RADIOGRAPH:• distal obstruction with multiple air-fluid levels (nonspecific)• huge and disproportionately dilated loop of bowel (highly suggestive) • “soap-bubble” appearance of retained meconium • dilatation of the proximal colon up to the level of the atresia, unless

multiple atresias are present. • CONTRAST ENEMA:

• microcolon, distal to the atresia with obstruction to the retrograde flow of barium at the site of atresia.

• hook or question-mark appearance at the site• colon is often non-fixed or malpositioned in the midline. • distal colon segment may perforate into the peritoneal cavity blind end is

covered with only mucosa.

Colon Atresia

Distended loops of bowel similar to those seen in low small bowel obstruction. Image from a barium enema study demonstrates microcolon with complete obstruction to the retrograde flow of a barium enema study demonstrates microcolon with complete obstruction to the retrograde flow of barium in the transverse portion of the colon.

Hirschsprung’s Disease(Aganglionosis of the colon)

• majority of cases , the aganglionic segment is limited to the rectosigmoid region (short segment aganglionosis). • always involves the anus and internal

sphincter and extends proximally for a variable distance.• transition point found in the rectosigmoid

(73%) > descending colon (14%) > more proximal colon (10%).

• RADIOGRAPHIC FEATURES:• features of distal bowel obstruction. • a dilated colon proximal to the distal and smaller aganglionic

segment typical finding• small gas-filled rectum can be seen (in prone film). • absence of rectal gas is not specific as also seen in infants

sepsis and necrotizing enterocolitis. • bowel pattern may appear normal. • pneumoperitoneum may be seen in patients with long segment

or total colonic disease secondary to colonic perforation• CONTRAST ENEMA:

• directed towards identifying the transition zone the most specific (where the normalsized, distal aganglionic bowel changes in caliber to join the proximal ganglionic bowel)

• funnel-shaped and it is an important diagnostic feature• FLUOROSCOPIC VISUALIZATION:

• irregular saw-toothed mucosal pattern disordered contractions in the aganglionic colon

• straight transverse bands in the involved segment of colon represent areas of persistent spasm

• Rectosigmoid index• This compares the ratio of the rectal diameter to the sigmoid

diameter• abnormal if the sigmoid colon is more dilated than the rectum • (R/S index <1) abnormal.

• Other: • Immediate postevacuation film collapsed distal aganglionic

segment. • Delayed radiographs (24 hours) prolonged retention of barium

(strong indicator) when enema findings - inconclusive• colon that is shortened with flexures pulled down and rounded in

appearance (question mark colon) • true microcolon appearance is rare

• Confirmation:• suction biopsy taken 2 cm above the dentate line,

as below this line the normal anus shows relative hypoganglionosis. CONTRAST ENEMA CAN BE SAFELY PERFORMED 24 HOURS AFTER A SUCTION BIOPSY, THOUGH IDEALLY THE ENEMA SHOULD PRECEDE A BIOPSY.

• IN EQUIVOCAL CASES,• ANORECTAL MANOMETRY:• relies on anal sphincter reflex relaxation in response

to distention of the rectum • Absent in patients with Hirschsprung’s disease.

• ENTERECOLITIS IS A MAJOR CAUSE OF DEATH & ENEMA IS CONTRAINDICATED IN THESE PATIENTS.

Plain X-ray abdomen showing a dilated proximal sigmoid colon with a smaller distal sigmoid with relatively little rectal gas in a neonate

Barium enema shows an abrupt transition from the narrow caliber rectosigmoid (aganglionic) to the larger caliber more proximal sigmoid colon

Meconium plug syndrome

(a) BARIUM ENEMA study shown a normal-sized rectum and colon

with inspissated meconium filling defects. (b) Gross

specimen shown the colon and the typical

appearance of an evacuated plug.

Anorectal Anomalies

• ATRESIA: rectal atresia, imperforate anus• FISTULA: perineum, vestibule, vagina,

urethra, bladder.• RADIOGRAPH:• Low small bowel or colonic obstruction• Prone shoot though radiographdetermine the

level of atresia and assessment of the sacrum.

• M-line horizontally through the junction of the lower third and upper two third of the ischium level of the puborectal muscle

• Classify lesion: high, intermediate or low.

• ULTRASOUND:• Delineating distance from the distal pouch to perineum• <10 mmlowsimple perineal anoplasty• >15mm high diversion & colostomy

• CYSTOGRAPHY:• Delineates associated fistulas between terminal bowel and

urinary tract.

• CT & MRI• Modalities of choice• Help determine presence of puborectal muscle, ext

sphincter and rectal pouch.

IMPERFORATE ANUS: Lateral voiding cystogram demonstrates an air-filled distal rectal pouch ending blindly below the “M” line. low lesion. No fistula is opening the terminal bowel.ECTOPIC ANUS - Voiding cystogram demonstrates a recto-urethral fistula.

References:• Grainger & Allison's Diagnostic Radiology: Textbook of Medical

Imaging, 6th edition

• Gore & Levine textbook of gastrointestinal radiology, 2nd edition.

• Textbook of radiology and imaging - David Sutton.

• Diagnostic Radiology Paediatric Imaging. AIIMS_MAMC_PGI series.

• Gupta A: Imaging of Congenital Anomalies of the Gastrointestinal Tract.Indian Journal of Pediatrics, Volume 72—May, 2005

• Berrocal: Congenital anomalies of Small Intesine, colon and rectum. Radiographics 1999;19:1219-1236.

• Berrocal: Congenital anomalies of Upper gastrointestinal tract. Radiographics 1999;19:855-872

Thank you.