Radiology of the Pediatric Abdomen Ruba Khasawneh, MD

The blue words and boxes are the additional notes from the lecture. Added by Jalal akawi jraisat Forgive me for any mistakes.

Radiologic diagnosis modalities Plain films (the first investigation in patients presented to ER with abdominal pain) Barium studies US/CT and MRI Nuclear medicine studies

Modalities-Plain films Should cover the entire abdomen from GE junction to rectum Supine (e.g. constipation), Supine/upright (intestinal Obstruction, perforation) and Acute abdominal series ( acute abdominal series includes supine/upright abdominal x-ray –left lateral decubitus is obtained if the patient can’t tolerate upright position- in addition lateral chest x-ray , we use it when we cant localize the pathology in irritable infants and nonverbal patients like CP patients as 1st line investigation) Check lines placement (the 1st thing to see in X-ray) Bowel gas pattern, A/F levels (in case of intestinal obstruction) Presence of abnormal calcifications/FB or soft tissue opacities Presence of free air(air in the peritoneal cavity), pneumatosis (air in the bowel wall), ? Ascites (x-ray is non-specific for ascites but you can see full flanks and displacement of bowel loops centrally) Other (pathology in lung bases in upper part of abdomen and bones)

Modalities-US Can be performed portably No radiation Masses , fluid collections/abscesses and ascites 1st investigation in appendicitis, pyloric stenosis Target (pseudokidney) sign seen in intussusception

Modalities-CT/MRI CT : Masses, abscesses, appendicitis, acute abdomen in non-verbal patient, etc… MRI: Masses, MRE (MR enterography in case of inflammatory bowel disease) Risk of radiation (CT) and sedation if needed (MRI)

Modalities-NM Biliary atresia GER Meckel’s diverticulum

Case 1

Fig 1 air filled pouch adjacent to trachea(atretic esophagus) Inability to pass NG tube Fig 1

Scoliosis of the spine because of VACTEREL association Right upper lobe pneumonia because of aspiration (it is the most common site for pneumonia in those pts) Presence of distal bowel gas indicates that there is a Tracheoesophageal fistula. if there is no gas then its isolated atresia alone with no fistula. Scoliosis of the spine because of VACTEREL association Fig 2

Imaging Findings Fig 1 : Multiple frontal x-rays of the chest and abdomen demonstrating enteric tube (NG) at the level of the upper thoracic region with a distended upper pouch. Note the presence of bowel gas in the abdomen. There is also collapse/consolidation of the right ULL Fig 2: Note the presence of multiple vertebral anomalies in the lumbar region

Diagnosis: Esophageal atresia with TEF

Discussion- TEF Incidence 1 in 3500 , Etiology not well known, faulty separation between esophagus and trachea Esophageal atresia with distal fistula> esophageal atresia alone> TEF w/o esophageal atresia Increased incidence with Down’s 30% born premature Commonly associated with other anomalies: VACTERL, imperforate anus, duodenal atresia Vertebral anomalies “e.g. lumbar scoliosis”, anorectal anomalies “imperforate anus”, Cardiac anomalies, TE, Renal anomalies, birth defects Associated with polyhydramnios, feeding abnormalities and respiratory compromise

Esophageal Atresia / TE Fistula

Case 2

Bowel loops in the right hemithorax and hypoplastic right lung with shifted mediastinum to the left .(right diaphragmatic hernia) Fig 1

Fig 2 Bowel loops in the left hemithorax ,left lung hypoplasia and partial hypoplasia of the right lung . notice that NG tube is in the chest.

MRI done for prognostic assesment of lung maturity Fig 3 MRI done for prognostic assesment of lung maturity

Imaging Findings Multiple bowel loops seen in the right hemithorax in Fig 1 and left hemithorax in Fig 2 with hypoplasia of both lungs. Note the position of the NG tube in Fig 2 and the same findings in the corresponding fetal MR.

Diagnosis: Congenital diaphragmatic hernia

Discussion- CDH 1 in 2000-4000 live births Patent pleuroperitoneal canal, might contain liver, spleen, stomach and bowel M:F 2:1 L:R 9:1 Associated anomalies in 20% Mortality related to lung hyoplasia

Case 3

Ultrasound is the investigation of choice in pyloric stenosis. gallbladder Increased muscle wall thickness Elongated pyloric canal

HPS Longitudinal section of pylorus shows the donut sign Transverse section shows the hamburger sign.

Imaging findings Multiple U/S images demonstrating abnormal elongation of the pyloric channel with thickening of the hypoechoic muscle layer. Length > 16mm Muscle thickness > 3mm

Diagnosis: Hypertrophic Pyloric Stenosis

Discussion-Hypertrophic pyloric stenosis Incidence 3/1000, age 0-3 months(typically 4-6 weeks ) 4-5 times more common in boys, 1st born Familial: maternal > paternal Hypertrophy of muscular channel Projectile vomiting, non-bilious Dehydration, weight loss Hyperperistalsis, palpable olive Hy

Abnormal contractility Barium meal study reveals no passage of barium and abnormal peristaltic movement which is called the caterpillar sign. Abnormal contractility

Discussion-cont’d U/S modality of choice UGI radiation, time consuming Pylorospasm is a pitfall! (pylorospasm is transient and the pyloric canal will not be elongated) Treatment surgical ( pyloromyotomy )/ medical in Europe

Normal VS. abnormal pylorus-US

Case 4

Double bubble sign

Imaging findings Frontal x-ray of the chest and abdomen demonstrating “Double bubble sign” ; gas in the gastric fundus and in the duodenal bulb with absent gas in the rest of the abdomen.

Diagnosis: Duodenal atresia

Discussion-Duodenal atresia Prevalence 1 in 5000-10000 No sex associated difference in prevalence Defective canalization Associated anomalies in 60%, Down’s (25%), GI, GU, CHD, VACTERL Distal to ampulla of Vater in 80%( bilious vomiting), non-bilious vomiting if proximal

Case 5

stomach 1st part of duodenum Normally when doing barium meal the 4 parts of the duodenum should be seen with the doudenojujenal junction to the left of the spine and the majority of bowel in the left side . but in this case there is no crossing to the left side and the majority of bowel in the right. So it is malrotation. One of the complications of malrotation is volvulus with corck screw appearance

Abnormal position of mesentric vein and mesentric artery

Imaging findings Contrast UGI study demonstrating abnormal repositioned DJ junction lower than the duodenal bulb and to the right side of the spine. Note the corkscrew appearance of the more distal small bowel and the whirlpool sign on the US image.

Diagnosis: Malrotation with midgut volvulus

Discussion- Malrotation with midgut volvulus First week of life Malrotation alone with no volvulus can go un noticed and discovered incidentally later in life. Ill infant with bilious emesis and abdominal distention Absent normal attachments of the mesentery to the posterior abdominal wall with narrow mesenteric stalk ( which contains the SMA and SMV) Malrotation is always present with omphalocele, gastroschisis, diaphragmatic hernia

Discussion-cont’d 60% associated anomalies: duodenal atresia, annular pancreas , CHD with heterotaxy, diaphragmatic hernia, imperforate anus, etc... In older children can present with failure to thrive, recurrent abdominal pain and malabsorption. Tx: Surgical emergency ( Ladd procedure)

Normal bowel rotation-UGI

Case 6

Multiple dilated bowel loops with paucity of gas distally , indicating distal intestinal obstruction

Imaging findings Multiple distended loops of small and large bowel concerning for low bowel obstruction. Differential diagnosis in the neonatal peroid include: 1- Imperforate anus 2- Hirshprung’s disease 3- Meconium ileus 4- Ileal atresia 5- Meconium plug syndrome

Differential diagnosis in the older child include: 1- Incarcerated hernia 2- Intussusception 3- Appendicitis 4- Adhesions 5- Meckel’s diverticulum Double “I” double “A” And M

RULE OF THUMB - 2or less dilated loops of bowel on abdominal x-ray indicates high bowel obstruction study from above (barium meal) - 2 or more dilated loops of bowel on abdominal x-ray indicates low bowel obstruction study from below (barium enema)

Case 7

Reflux of contrast into ileal loops with multiple filling defects Small caliber of colon (micro colon)

Imaging findings Barium enema showing small caliber of the entire colon “microcolon” with reflux of contrast into the proximal ileum which contains multiple filling defects “inspissated meconium”. Note the multiple distended bowel loops throughout the abdomen.

Diagnosis: Meconium ileus vs. Ileal atresia

Discussion- Microcolon No passage of normal enteric contents during development Ileal atresia: ? Vascular accident in utero, Microcolon with no reflux of contrast into SB. Other atresias common Meconium ileus: associated with CF, increased meconium viscosity, complications(more common in meconium ileus than atresia) in 50% ( atresia, perforation, meconium peritonitis and volvulus) ,Microcolon with inspissated meconium.

Case 8

First do Lateral study to see the rectum- sigmoid ratio spine Transitional zone rectum

After lateral study do AP study. sigmoid Transitional zone rectum

Imaging findings Contrast enema studies demonstrating abnormal recto-sigmoid ratio of less than 1 with transition zone seen at the rectum. Note also the multiple dilated bowel loops throughout the abdomen consistent with low bowel obstruction.

Diagnosis: Hirshprung’s Disease

Discussion- Hirshprung’s disease Congenital disorder/ absent ganglion cells in the myenteric plexus (auerbach plexus) Affects 1 in 4500-7000 newborn More common in white, M>F Hereditary in 12.5% (typically total colonic aganglionosis) Present with chronic constipation Diagnosis? Barium enema, definite diagnosis is rectal biopsy

Case 9

Intussusception possible findings in general : 1)Normal x-ray 2)Dilated bowel loops “low bowel obstruction” 3)Paucity of gas in the right abdomen and if you follow the bowel in the left side there is cut off point that represent the crescent sign . Which is the case in this patient Crescent sign Paucity of gas in the right side abdomen

Ultrasound is the second step after x-ray ,and shows Target sign or pseudo kidney sign

Those slides represent the stages in the management of intussusception by air enema. Intussusception was encountered in the right upper abdomen. Crescent sign and around it is the intussusception While pumping air in the colon intussusception was relieved and the gas descend to the cecum and stopped at the ileocecal valve. Keep pumping till you see reflux of air in the small bowel .intussusception was reduced. Complication of this procedure is perforation that need surgical intervention . another complication is recurrence so you should observe pt 24 hours after the reduction.

Imaging findings Abdominal x-ray showing a soft tissue opacity in the right upper quadrant with paucity of gas in the right side of the abdomen. U/S images demonstrating a donut shape structure in the right lower quadrant( intussusception) containing multiple lymph nodes Air enema study showing successful reduction of the intussusception with reflux of air into the small bowel

Diagnosis: Intussusception

Discussion- Intussusception Invagination of bowel into itself Ileocolic is the most common 75% < 2 years Rare less than 3 months. So it occurs between 3 months and 2 years. Idiopathic in >95%, lymphoid hyperplasia Pain , mass and bleeding Tx: Reduction enema; air safer than liquid, 5% recurrent, surgery if unsuccessful Treatment can be repeated up to 4 times.

Case 10

Bowel in the scrotum indicates huge inguinal hernia

The same as the previous one but here there is dilated bowel loops because of intestinal obstruction as a complication of incarcerated hernia.

Imaging findings Chest and abdominal x-ray demonstrating multiple dilated bowel loops with large bilateral inguinal hernias extending into the scrotum. Abdominal x-ray showing multiple dilated loops of bowel with small left inguinal hernia

Diagnosis: Incarcerated Inguinal Hernia

Discussion- Inguinal hernia Most common cause of obstruction> day 4 M:F 9:1, R:L 5:1 Increased inguinal fold Gas in the scrotum

Case 11

Remember that appendicitis is a clinical diagnosis. fecolith

Possible findings for appendicitis in general on x-ray: 1)Normal 2)Dilated bowel loops because of intestinal obstruction 3) multiple LOCALIZED air fluid levels(as in this x-ray) in the right side of the abdomen indicating ileus at THAT site . but in case of intestinal obstruction the air fluid levels are more and not localized to one side.

Normal appendix on US should appear : 1)Less than 6mm 2)Compressible 3)Visible peristalsis 3)Fat around it appears dark on US while when there is inflammation it appears white.

The appendix is thickened and the fat around it appears white and you can see a fecolith in the middle.

Indications for CT scan: 1)Sometimes appendix cant be seen on ultrasound because it is retrocecal. 2)No findings on ultrasound but still there is clinical suspicion. An it should be an enhanced study with oral and IV contrast 747238 appy 15 y/o

Imaging findings Abdominal x-ray showing multiple dilated loops of bowel with multiple air-fluid levels seen mainly in the right side of the abdomen (ileus) with appendicolith in the right lower quadrant seen in a different patient. Ultrasound exam demonstrating a blind ending tubular structure in the RLQ which measures >6mm, is incompressible with loss of mucosal details and increased echogenicity of surrounding fat. Note also the intraluminal appendicolith. CT scan showing distended hyperemic appendix with appendicolith and surrounding inflammatory changes and free fluid.

Diagnosis: Acute appenidicitis

Discussion- Acute appendicitis Most common cause for emergent surgery in children 4/1000 8-9% life time risk Presentation: periumbilical pain that moves to RLQ, N., V., anorexia and fever Clinical diagnosis, difficult exam in the young patients, US/CT

Normal appendix

Case 12

(trace the blue line in this x-ray) Radiolucency that can be traced by a pencil and gives the shape of American football ,called the football sign. (trace the blue line in this x-ray) Falciform ligament that appeared because of surrounding air ,normally you cant see it . Rigler’s sign (well defined bowel wall appeared in the presence of extra intestinal air)

Imaging findings Large amount of free intraperitoneal air ( pneumoperitoneum) outlining the falciform ligament , note also the football sign and Rigler’s sign(air outlining both sides of the bowel ).

Diagnosis: Pneumoperitoneum

Discussion- Pneumperitoneum Perforated viscus: Idiopathic(idiopathic rupture of stomach or cecum), NEC, ulcer Dissection from mediastinum or retroperitoneum Post operative Might be difficult on supine abdominal x-rays Need horizontal beam view: cross table lateral or left lateral decubitus view

Abnormal lucency laying the liver ,which is the most common site for pneumoperitoneum.

Case 13

2)Pneumatosis intestinalis NEC: 1)Dilated bowel loops 2)Pneumatosis intestinalis

Abnormal branching lucency in the liver represents portal venous gas because of the resulted sepsis

Imaging findings Multiple abdominal x-rays demonstrating multiple dilated bowel loops with extensive pneumatosis intestinalis. Note also the extensive portal venous gas resulted from sepsis.

Diagnosis: Necrtoizing enterocolitis with pneumatosis intestinalis and portal venous gas

Discussion-NEC Ischemic injury to bowel, 90% preterm/10% term( Hirshprung’s/ CHD) Risk factors: prematurity, hypoxia, hyperosmolar feeds, stress, UAC Hypoperfusion: sepsis, PDA and CHD Loss of mucosal integrity Altered enteric immunity: decreased IgA in preterm Bacterial overgrowth, invasion Ileocecal region most common

Discussion-NEC Radiology: 1- Dilated fixed bowel loops(fixed means that the serial x-rays over time show same location of gas in each time the x ray is done which is abnormal and means ischemia) 2- Pneumatosis intestinalis: linear(subserosal), bubbly( submucosal) 3- Portal venous gas 4- Pneumoperitoneum Complications: short bowel, stricture, fistulas.

Normal neonatal x-ray Mosaic pattern . CUBES not TUBES

NEC- US Not required from us

Case 14 The coming cases are not required from us (they are not coming in exam)

Coin in esophagus .

battery 1377900Batteries FB Discussion -coins are most commonly swallowed FB -Button batteries show a characteristic double-density (2-layer) shadow. Laterally, their edges are rounded with a step-off junction at the positive and negative terminals Are important to identify since they may cause caustic burn injury to esophagus If battery has remained in stomach/GI tract for more than 24-48 hours, then removal is recommended (corrosion has been documented as early as 6 hours after ingestion) -Nonradio-opaque FB: hot dog is most common, with plastic toys also commonly ingested battery

Stones. 1421336 2 yr 4 mo rock ingestion