Imaging of Pediatric Abdominal Disease

Mark S. Finkelstein DO, FAOCR Department of Medical Imaging

What is our goal?

. Familiarize pediatricians to a variety of common pediatric GI disorders . Outline a practical approach to imaging pediatric GI diseases . Review current methods & discuss current imaging techniques for the evaluation of pediatric GI disease

What is the purpose of the plain film abdomen study?

. Foundation of GI imaging . Distinguishes surgical vs. non-surgical disease . Considerations – AP supine: . Used to evaluate vague or chronic abdominal pain – Horizontal beam: . Used to demonstrate free intra-peritoneal air (erect,supine cross table lateral or decubitus) – Prone: . Useful for differentiating large from small bowel . Useful for excluding SBO Common Imaging Techniques

. Fluoroscopy . Ultrasound . CT . Nuclear Medicine . MRI Fluoroscopy Technique

. Fasting time: – Premature = 2-4 hours NPO – Infant < 2 1/2 yrs = 4 hours NPO – Children > 2 1/2 yrs = 6 hours NPO . Digital low dose fluoroscopy with small field size . Contrast medium: – Barium is best – Air – Other options: . Gastrograffin (GG) = High osmolality, water soluble warning: GG should only be used by qualified experienced pediatric radiologists . Metrizimide, Iohexol, Iopamidol, etc.= low osmolality, non-ionic water soluble Ultrasound Technique

. Abdomen Prep (Complete/Limited) Fasting time: – Children < 5 yr. = 4 hours NPO – Children > 5 yr. = 8 hours NPO . Renal/Pelvic Prep – Infant < 1 yr. = Patient given formula, juice during exam – 1yr- 10yrs = Child must drink 12-16 oz clear fluid 1 -2 hrs prior to exam – > 11 yr. = Child must drink 24-32 oz clear fluid 1 -2 hrs prior to exam

Children who are continent should not empty bladder 3 hrs prior to renal US exam CT Technique

. Exam tailored to specific area or question . Spiral imaging technique . Minimal radiation . “Frush” Rainbow Protocol

low kV, low mA

. Intravenous non-ionic contrast delivered via power injector . Oral contrast not always necessary Nuclear Medicine

. Provides physiologic information . Radionuclides – 99m Technetium - based – 111 Indium - rarely used – 123 Iodine - rarely used MRI

. Particularly useful for IBD imaging – Limiting factors include peristaltic motion & limited spatial resolution . Excellent soft tissue/vascular discrimination . Usually requires sedation: – Nembutal IV: 2-6 mg/kg – Versed: max is 10 mg . Intranasal:0.2 mg/kg . PO: 0.4 mg/kg . IV: 0.1 mg/kg . Nursing and Recovery required & Tracheoesophageal Fistula (EA & TEF)

. Cause: – Failure of formation & separation of primitive foregut into respiratory & digestive tracts – Occurs during 3rd & 5th week of intrauterine life . Incidence: 1:2000 - 4000 livebirths

Classification of EA & TEF

. Atresia without fistula . Proximal fistula and distal atresia . Proximal and distal fistula . Proximal atresia and distal fistula . Fistula without atresia

Symptoms of EA &TEF

. Drooling . Respiratory distress/Cyanosis with feeds . Cough/choking with feed . Regurgitation of ingested fluids . Vomiting . Inability to pass NG tube . Retrotracheal air-filled pouch . Recurrent pneumonia Associates Anomalies with EA &TEF

(ARTICLES) . Anal atresia (20%) . Renal (12%) . TE fistula . &/or malrotation . Cardiac (15- 39%) PDA, VSD . Limb anomalies (24%) radial hypoplasia, polydactyly . Esophageal atresia . Spinal anomalies EA without Distal Fistula

No bowel gas! EA with Distal Fistula

Bowel gas! “ H” Type Fistula Complications of EA & TEF repair

. Esophageal stenosis . Esophagomediastinal fistula . GER . Esophageal diverticulum . Impaction of ingested material at anastomosis Proximal and Distal Atresia

Pre-op: Proximal Post op: Discontinuity of & distal atresia with anastomotic site- marking cannula breakdown of anastomosis with leak above & below Interventional Radiology Repair

Wire (arrow) from below Snare (arrow) from above Grasped and pulled together Once ends caught then wire pulled through & converted to silk suture

Post-Interventional Care and Follow-up

Post treatment Balloon Final result stenosis dilations one year later Complication: Food Impaction at Anastomosis

Tx: IR Balloon Dilatation Esophageal Stricture & Stenosis

. Etiologies – Esophageal Web: . 1-2 mm vertical length . Area of complete or incomplete narrowing – Rings: . 5-10mm vertical length . Area of complete or incomplete narrowing – Strictures . >10 mm vertical length

Causes of Esophageal Stricture (LETTERS MC) . Lye ingestion . Esophagitis (reflux) . Tumor . Tubes (prolonged NG intubation) . . Radiation . Surgery/Scleroderma . Moniliasis . Congenital Common Foreign Bodies & Chemical Ingestion

. Alkaline Agents . Acids . Phenols . Silver Nitrate . Batteries: Injuries are more extensive and have poorer outcomes if battery is a lithium “ flat coin” battery. Maximum damage is inflicted within 2 to 2.5 hours after the ingestion. . Coins Attempted Suicide via Lye Ingestion

Initial CXR 6hrs. later Pulmonary edema Post Lye Ingestion Stricture

Colon Interposition: End stage treatment secondary to prior Lye Ingestion

StrictureInitial Barium 6Swallow weeks later Intrinsic causes for Intestinal Obstruction

. Antral Web . Duodenal Web . Duodenal Stenosis . .

Antral Web (Antral mucosal diaphragm)

Presentation: . Age: 3mos. - 80 yrs. . Located 1.5 cm from pylorus . Symptomatic if opening < 1 cm . 2 - 3 mm thick symmetric antral band perpendicular to long axis of stomach Association: . gastric ulcer (30-50%) Classic x-ray appearance . “double bulb” antrum in profile . concentric/eccentric orifice . normal gastric peristalsis at site of lesion Antral Web Duodenal Atresia, Stenosis & Web

. Cause: Failure of duodenal canalization or recanalization during 3rd-6th or 6th-11th week gestation . Incidence: 1:10,000 livebirths . Frequency: M = F . Clinical presentation: – Prematurity – Polyhydramnios – Bilious emesis in first hours of life

Duodenal Atresia, Stenosis & Web

. Associations: . Trisomy 21 (Down’s syndrome): – 30%Coexisting congenital heart disease – VATER Syndrome . Location – Atresia/Stenosis occur in region of Ampula of Vater . (80% just distal to ampulla) – Concurrent annular pancreas found in 20% of cases of duodenal atresia/stenosis Duodenal Atresia

Note: Hepatopancreatic duct anomaly can permit air to move distal to the obstruction in duodenal atresia.

Courtesy of www.adhb.co.nz Duodenal Web (duodenal diverticulum) Duodenal Web

Courtesy of Dept of Surgery: Brown Medical School http://bms.brown.edu Annular Pancreas

. Most common anomaly of pancreas . Cause: Abnormal ring or collar of pancreatic tissue that encircles the duodenum secondary to abnormal migration of the ventral pancreas (head & uncinate) . Location: – 2nd portion duodenum (85%) – 1st/3rd portion of duodenum (15%) . Age of discovery: 50% childhood, 50% adulthood Annular Pancreas . Symptoms: . Abdominal pain (70%), . Nausea & vomiting (60%), . Jaundice (50%), . Hematemesis (10%) . Satiety . Feeding difficulties . X-Ray findings: . Polyhydramnios . Enlarged head of pancreas . “Double bubble” sign . Treatment: Surgical bypass Annular Pancreas

Diagram courtesy of www.henryfordhealth.org CT Annular Pancreas Extrinsic causes for Intestinal Obstruction

. Hypertrophic . Malrotation . Volvulus . Gastrointestinal duplications . Intestinal Atresia . Intestinal Hematoma Hypertrophic Pyloric Stenosis

. Cause: Idiopathic hypertrophy and hyperplasia of circular muscle fibers of pylorus . Incidence: 3:1000; M:F=4-5:1 . Inherited as a dominant polygenic trait . Increased incidence in firstborn boys . Age of onset: 2-8 weeks of life . Symptoms: – Non-bilious projectile vomiting (15-20%) – Palpable olive (80%) by experienced surgeon, false positive rate (14%) – Nasogastric aspirate >10ml NPO 4 hrs (92%sensitive, 86% specific)

Hypertrophic pyloric stenosis: volumetric measurement of nasogastric aspirate to determine the imaging modality. M S Finkelstein, G A Mandell and K V Tarbell. December 1990 Radiology, 177, 759-761.

HPS

. Radiographic Findings: . UGI (95% sensitive) – elongated pyloric channel – “double track” sign – “string” sign – “Twining recess” = “diamond “ sign – “Pyloric teat” sign – “Antral beak” sign – “Kirklin” sign”= “mushroom” sign = indentation of base of duodenal bulb – “caterpillar “ sign = Gastric hyperperistalsis – Gastric Atony UGI findings of HPS HPS

. Ultrasound Findings: – “Target” sign= hypoechoic ring around echogenic mucosa – “Cervix” sign = indentation of muscle mass on fluid filled antrum – “Antral nipple” sign = redundant pyloric mucosa protruding into antrum – Pyloric length>14 mm – Pyloric muscle thickness >4mm – Pyloric diameter >13mm US findings of HPS

Channel length = 1.53cm Muscle thickness = 0.45cm Normal Bowel Fixation

Ligament of Treitz (LOT) a. Left of midline b. Approx. halfway between greater & lesser curvature of stomach c. At level of duodenal cap

Norma l Mesentery: a. Fan-like mesentery from LOT to cecum Malrotation

. Definition: General term for any abnormal variation in intestinal rotation . Malposition of intestine does not unto itself cause problems... however this condition is frequently accompanied by malfixation… which can lead to fibrous bands (Ladd’s bands) and subsequent obstruction or intestinal volvulus Malrotation

Ladd’s bands originate from malpositioned Abnormal small bowel mesenteric cecum. Causing transverse compression of attachment: duodenum and mechanical obstruction * Short pedicle increases risk for volvulus Malrotation without Volvulus Courtesy of www.emedicine.com Malrotation with Volvulus Courtesy of www.emedicine.com

Color Doppler shows malrotation with midgut volvulus. The "whirlpool sign” is created by the Abnormal relationship of the superior superior mesenteric vein as it wraps around the mesenteric vein (V) to the superior mesenteric superior mesenteric artery artery (A). Normally vein lies to right of artery. Gastrointestinal (Enteric) Duplication Cysts

Location: Ileum 30-33% 17-20% Colon 13-30% Jejunum 10-13% Stomach 7% pylorus,duodenum, ileocecal jt., <4%

Enteric Duplication Cyst (EDC)

. Age at presentation: 1st year of life . Associate with other anomalies (esp. esophageal) . Sign & symptoms: . Mass . Abdominal pain . Distension . Obstruction (EDC)

. Description/Types: – Spherical: Does not communicate with GI tract – Tubular: Frequently communicates with GI tract

Lined by alimentary tract epithelium . Frequently has ectopic gastric mucosa or pancreatic tissue . Have smooth muscle in their wall . Share muscular wall and blood supply with adjacent bowel

Radiographic findings of EDC

. Plain film: – Solid mass – Obstruction . UGI – “Mass like” extrinsic compression of adjacent bowel . If tubular EDC may fill with contrast . US – Cystic mass – Echogenic inner layer (mucosa) with hypoechoic outer rim (muscle) = classic “gut signature” EDC

GB

Cystic mass lying adjacent to gallbladder (GB). Double wall typical of a duplication cyst.

Lucent lesion (arrow) medial to duodenal sweep

T2-weighted image shows high signal fluid within the cyst and low signal from bowel wall. Intestinal Atresia

. Cause: sporadic vascular accident . Incidence: 1:300 livebirths . Location: – jejunum + ileum (70%) – duodenum (25%) – colon (5%) – multiple sites . Prognosis: 88% survival for isolated atresia Radiographic findings in Intestinal Atresia

– “Bulbous bowel segment” sign secondary to impacted intestinal contents (dilated loop of bowel proximal to atresia) – “Triple bubble” sign (dilated air filled stomach + duodenal bulb + proximal jejunum) – meconium peritonitis – polyhydramnios (50% with duodenal/proximal jejunal atresia, rare with ileal or colonic)

Types of Jejunal &Ileal Atresia

. Type I: mucosal web . Type II: fibrous cord . Type IIIa: mesenteric gap defect . Type IIIb: "apple peel" deformity . Type IV: multiple areas of intestinal atresia

Jejunal Atresia: Mucosal Web

Courtesy of: www.gfmer.ch

Jejunal Atresia (Apple peel)

Courtesy of www.vh.org Meconium Peritonitis Intramural Intestinal Hematoma

. Potential causes: – Trauma: accidental vs. non-accidental – Warfarin therapy – Henoch-Schoenlein purpura coliti – Meckle’s diverticulum – Necrotizing Enterocolitis – Volvulus Gastrointestinal Hematoma

. UGI: – Circumferential blood collection causes intraluminal narrowing . CT: – dumb-bell shaped soft tissue mass – peritoneal fluid collection – bowel wall thickening – intense bowel wall enhancement – bowel dilatation . US – Submucosal, diffuse bowel wall thickening Traumatic Duodenal Hematoma SB Hematoma secondary to anticoagulation

SBFT: Typical palisade aspect of wall CT: Thickened bowel wall secondary to hematoma MRI of the

. Primary role in pediatric imaging : – Define type and severity of hepatobiliary disease – Define type and severity of inflammatory bowel disease (IBD); – Identifying enteric abscesses and fistulae . Additional role (usually in adults) – Preoperative staging of malignant neoplasms, including rectal carcinoma – Differentiating postoperative and radiation therapy changes from recurrent carcinoma – Follow-up evaluation of metastases response to localized ablative or systemic chemotherapy MRI Imaging – Characterization of liver and pancreatic tumors – MR cholangiopancreatography (MRCP) . Cholilithasis . choledochal duct malformations . posttraumatic, postoperative and/or postinflammatory changes of the pancreaticobiliary tree. – Identify inflammatory or infectious conditions of bowel – Identify vascular malformations – Diagnosis and/or differentiate oncological disease . excellent tissue contrast and tissue resolution but also has shown promising advances in functional imaging techniques such as diffusion- weighted imaging (DWI) and MR-spectroscopy (MRS) 18yr old male with history of Crohn’s disease

Multiple featureless and patulous loops of distal jejunum/proximal ileal bowel. 13 yr old female with chronic abdominal pain R/O IBD

Inflammatory changes affecting the distal and terminal ileum, which support diagnosis of Crohn's disease MRCP: 7 yr old female with acute pancreatitis and sudden bump in LFTs and lipase

The common bile duct measures Intervalapproximately resolution 7 mm previously in diameter. seen The intra and extrahepaticcommon hepatic biliary duct ductal measures dilatation up to and 9.5 pancreaticmm in diameter. ductal Thedilatation. gallbladder is distended with fluid. Although no gallstones are seen within the gallbladder, there is a meniscus “ sign” (arrow) in the central common bile duct at the head of the pancreas, suggesting an intraluminal filling defect from either a stone or small mass. Pediatric Hepatobiliary Imaging Reference

Hepatobiliary and pancreatic imaging in children—techniques and an overview of non-neoplastic disease entities Rutger A. J. Nievelstein,Simon G. F. Robben, and Johan G. Blickman Pediatr Radiol. 2011 January; 41(1): 55–75.

Other Intestinal Pathology

. Cystic Fibrosis . Appendicitis . Hirschsprungs disease . Intussuception

Cystic Fibrosis (CF)

. Cause: Autosomal recessive disorder (transmembrane conductance regulator gene - chromosome 7) effecting exocrine glands. . Over 230 different gene mutations . Incidence: 1:2000 -2500 live births (Caucasian) . M:F = 1:1 . Uncommon in African Blacks, Oriental & Polynesian . Age at diagnosis: Mean age= 2.9 yr. . 1st year of life (70%) . by age 4 (80%) . by age 12 (90%) GI manifestations of CF

. Chronic obstipation . Pneumatosis intestinalis of colon . Failure to thrive (5%) . Meconium ileus (*earliest . “Microcolon” manifestation, 10-16% at birth) . “Jejunization of colon” . Meconium plug syndrome (25%, . Malabsoprtion most common cause of colonic . Pancreatic insufficiency obstruction in infants) . Hepatic Cirrhosis (2o to biliary . Meconium ileus equivalent obstruction) syndrome (10- 47% of older child/young adult) . Cholelithiasis . Peritonitis . Rectal prolapse (18-23% untreated patients)

. Intussusception Clinical presentation of CF

. Progressive abdominal distension . Bile stained vomitus . Absent or abnormal scanty stools . Dilated bowel loops & visible peristalsis below thin, shiny abdominal wall . “Putty” sign : Firm intestinal loops retaining an indented shape after abdominal palpation

Meconium ileus (MI)

. 10-15% of infant with CF present with MI . Earliest manifestation of CF . Virtually all infants with MI proven to have CF . Thick, sticky meconium due to deficiency of pancreatic secretion

MI and contrast enema . Technique: Controversy regarding water soluble contrast agent: . Full strength Gastrograffin (1968-Noblett) . Recommendation: – Half strength Gastrograffin 1:1 ratio with sterile H20 or NaCL Warning: Gastrograffin is hyperosmolar! Can cause severe fluid shift and death. Use with extreme caution! . Alternative: Use Non-ionic water soluble contrast . Serial enemas – success rate: 50-60% – perforation rate: 2-3% GI manifestations of MI

. Microcolon . Empty colon Only occasional pellets of meconium . Small distal ileum, but larger than colon . Proximal dilated small bowel

US manifestations of CF

. Hyperechoeic bowel (60-70% of fetuses) . Distended meconium filled bowel . Meconium peritonitis (Ca+) . Echogenic pancreas . Fatty liver/cirrhosis . Esophageal varices

Labial calcifications 20 to meconium peritonitis

Other GI manifestations of CF

Esophageal Varices Pneumatosis Coli Intussusception

Imaging of Appendicitis

Plain film . Sensitivity: 20-40% without vs. 95% with appendicolith Ultrasound . Sensitivity: 80%, specificity 95% . Compression imaging essential Normal Appendix: <6mm diameter & <2mm wall thickness Indeterminate Exam: Inadequate compression or obscured by bowel gas Positive Exam: Non-compressable, blind ending tubular structure (sag), target lesion (trv) with >2mm wall thickness and >6mm diameter

Diagnostic Imaging Pathways - Acute Non-Traumatic Abdominal Pain in Children (http://www.imagingpathways.health.wa.gov.au/includes/dipmenu/abdopain/us.html

. Routine imaging is not required if a diagnosis can be established on history and physical examination. . The principal imaging technique for evaluating suspected appendicitis is graded-compression sonography. In children this has a sensitivity and specificity of between 78%-100%, and 88%-95% respectively. Sensitivity and specificity is higher for uncomplicated appendicitis compared to cases with appendiceal perforation. . Criteria for sonographic diagnosis is visualization of an incompressible appendix that has a maximal cross-sectional diameter greater than 6mm, identification of an appendicolith, positive sonographic McBurney sign, demonstration of a complex mass, or focal fluid collection representing a peri-appendiceal abscess following perforation.

CT imaging of Appendicitis Ref: Diagnostic Imaging Online May 9, 2003 www.diagnosticimaging.com

. % CT utilization: Geography plays a large role in which modality is used for diagnosis · Northeast: 50% · Northwest: 50% · Southeast: 58% · California: 36% · Midwest: 70% · Southwest: 30% . Applegate postulated geographic variation related to differences in training and staffing shortages. . Time of day affects modality used; ultrasound use increases at night . Most common CT technique used: Complete CT abdomen and pelvis, with IV and oral contrast. . Canadian respondents differed from USA counterparts with ultrasound used almost exclusively as primary modality for diagnosis. Acute Appendicitis

Mesenteric stranding (arrow) Enlarged, inflamed appendix (arrow) Normal abdomen

US: Abnormal enlarged appendix with increased flow Intussusception

. Most common abdominal emergency of early childhood . Leading cause of acquired bowel obstruction in childhood . Etiology: – Idiopathic (>95%) . mucosal edema with lymphoid hyperplasia – Lead point (5%) . Meckel’s diverticulum, polyp, duplication cyst appendiceal abscess, Henoch-Schoenlein purpura , inspissated meconium, etc.

Intussusception

. Incidence: peak age between 6 months and 2 years . 3-9 months (40%) . < 1 year (50%) . < 2 years (75%) . > 3years (<10%) . M:F = 2:1 . Symptoms: – “Acute” crampy abdominal pain (90%) – Palpable abdominal mass (60%) – “Currant Jelly” bloody stools (60%) . Location: . ileocolic (75-95%) . ileoileal (4%) . colocolic (<4%) X-Ray findings of Intussusception

. Plain film . Abdominal mass in RUQ (50-60%) . Small bowel obstruction (25%) . Loss of inferior hepatic margin . BE . “Coiled spring” appearance of bowel . Convex intracolic mass . CT . “Target” sign: Multiple concentric rings within a given loop of bowel . Proximal bowel obstruction US Findings in Intussusception

. “Doughnut/target/bull’s eye” sign (trv view) = concentric layers of alternating hypo/hyperechoic layers of bowel . “pseudokidney/sandwich” sign (sag view) = hypoechoic layers on either side of echogenic center of mesenteric fat . Color Doppler: Swirl of mesenteric vessels dragged between bowel wall of intussuseptum

Treatment of Intussusception

. Hydrostatic versus pneumatic reduction . < 1% mortality if reduction occurs <24 hours from initial onset . Success Rate: 70-85% . Contraindications: . pneumoperitoneum . peritonitis . hypovolemic shock . Perforation risk (0.4-2%) . less with air reduction technique . 3-10 % rate of recurrence

Shiel’s Pneumatic Reduction Technique

Some images courtesy of www.amershamhealth.com Other Diagnostic Techniques

Early SBO, paucity of “Target sign” Hydrostatic BE bowel gas RLQ Some images courtesy of www.amershamhealth.com

Diagnostic Imaging Pathways - Acute Non-Traumatic Abdominal Pain in Children (http://www.imagingpathways.health.wa.gov.au/includes/dipmenu/abdopain/us.html Hirchsprungs disease (Aganglionosis of colon,Aganglionic megacolon)

. Accounts for 15 to 20% of all intestinal obstruction . Cause: Absence of parasympathetic ganglia (Meissner plexus) and submucosal layers (Auerbach plexus) secondary to arrest of neuroblast migration along vagal trunk before 12 th week in utero . Incidence: 1:5000 -8000 livebirths . M:F = 4-9:1, risk 50X higher with Trisomy 21

Hirchsprungs disease

. Morbidity: Anastomotic leak 5%, Pelvic abscess 5% Wound infection 10% Intestinal obstruction 5% Post-op stricture 5-10%, . Mortality: . Untreated in infancy: 80% . Treated: 30% secondary to enterocolitis . Location: Short segment: 80% Total colonic aganglionosis: 5% Long segment: 15% Skip aganglionosis (extremely rare)

Hirschsprungs disease

. Symptoms: – Failure to pass meconium within first 24 hours of life – Intermittent constipation with paradoxical diarrhea – Abnormal rectal manometry – Abnormal BE . Abnormal rectosigmoid index . Transition zone . Marked retention of barium on 24 hour post evac film – Abnormal rectal biopsy . Treatment: . Swenson pull-through . Duhamel procedure . Soave procedure

Hirchsprungs disease Conclusion

Tried to familiarize general pediatricians to a limited variety of common pediatric GI disorders

Attempted to outline a practical approach to imaging pediatric GI diseases

Reviewed current methods & discussed “best” imaging techniques for the evaluation of pediatric GI disease Photo courtesy of www.heraldstore.com