03.01 Radiology: Imaging of Common GI Disorders Flashcards
Accumulation of modified opacities throughout the segments of the colon which represent fecal material
Mottled densities
Abundant mottled densities
Presents with constipation
Fecal retention/stasis
Abundance of gas in small and large bowels
Generalized gas-filled distention
Impaired propulsion of GI contents > hypomotility of GI tract in the absence of mechanical bowel obstruction > accumulation of gas in the bowels > distention
Ileus/hypomotility
Bowel gas has not resolved after more than 3 days
Paralytic ileus
Collection of gas in one area
Focal inflammation in a given region
Inflammation at the epigastric region or RLQ
Sentinel loop
in large bowel obstruction, the colon is gas filled and dilated down to the level of sigmoid colon
Maybe diverticular stricture
Cut-off sign
Intra-abdominal inflammation, such as with pancreatitis, can lead to a localized ileus
Sentinel loop
Closed loop obstructions
Abundance of gas-filled bowel loops in the center of the abdomen
Valvulae conniventes/plicae circulares are evident
Intermittent abdominal pain, vomiting, RUQ mass
Coiled spring
Coiled spring pattern: without contrast
May represent obstruction
Coiled spring pattern with contrast
Intussusception
Small-bowel obstruction
Demonstrated only in upright position
Air-fluid leveling
Small bowel obstruction
Represents small pockets of trapped air within the superior walls of the bowel in the valvulae conniventes
Increased peristaltic activity
Ovoid appearance due to meniscal effect of fluid between the valvulae conniventes
String of pearls
Small bowel obstruction
Lucent areas that appear like vertical lines
Secondary to increased peristaltic activity
Stretch/slit sign
Obstruction at the duodenum
Stomach distention
Single bubble sign
Maximum normal diameter of SI
30mm
Maximum normal diameter of LI
50-60mm
Maximum normal diameter of cecum
90mm
Most common pathology presenting with a single bubble sign
Palpable lesion in the epigastric area among newborns
Non-bilous vomiting
Hypertrophic pyloric stenosis
Encountered when 2 bowel loops are involved
Obstuction beyond the stomach but probably at/around the area of the duodenum
Possible etiologies: atresia, obstuction, extrinsic compression by the region adjacent to the duodenum, periduodenal anomaly, anything that involves the distal portion of the duodenum
Presents with bilious vomiting
Double bubble sign
Jejunal obstruction
Encountered when there are 3 loops involved
Signify a possible obstruction on the jejunum
Triple bubble sign
Volvulus (twisting of loop of intestine around its mesenteric attachment)
Vomiting, alternating diarrhea and constipation
Coffee bean sign
Volvulus at right apex
Sigmoid volvulus
Volvulus at left apex
Cecal volvulus
Complication of intestinal malrotation
Present with bilious vomiting
Common among newborns
Midgut volvulus
Inflammatory focus
Secondary to a collection of abscess or an inflammatory focus
Normal, not distended gas filled bubble loops except at sudden interruption of air
Cancer, inflammation
Colon cut-off sign
Bowel loops in R hemiabdomen
Prominent liver shadow
Splenic flexuer is much more superior to hepatic flexure
Hematomegaly
Chest films are sometimes needed to confirm the possibility of a perforated gas-containing organ
Crescent shaped
Trauma, iatrogenic perforation, GI tract disease, inflammatory conditions
Pneumoperitoneum
Normal air under left hemidiaphragm (stomach air or gastric bubble)
Magenblase
Collection of air follows the configuration of bowel loops
Presence of haustrations, usually present with no symptoms, incidental finding
Chilaiditi’s sign
Chilaiditi’s sign + pain
One of the causes of pseudoperitoneum and occurs when bowel gas is interposed between the liver and the hemidiaphragm resulting in pain
Chilaiditi’s syndrome
Lucent foci within the left hemithorax Hernias represent gas containing bowel loops in the chest Presence of borborygmi Tachypnea US
Congenital diaphragmatic hernia
More common congenital diaphragmatic hernia
Left hemithorax
Defect in lateral and posterior sides
Bochdalek
Less common congenital diaphragmatic hernia
Right hemithorax
Defect in anterior (at sternocostal angle)
Morgagnie
Collection of calcifications in the mid-epigastric region at the level of L2
Further confirm by other imaging modalities
Round, hyperdense, middle portion of abdomen
Chronic pancreatitis, neoplasm, sub-intraparenchymal hemorrhage, hyperparathyroidism, cystic fibrosis
Pancreatic calcifications
Fat, forty, fecund, female
(+) Murphy’s sign and Collin’s sign
Cholelithiasis
Cholelithiasis: gold standard, cheap and readily available
US
Cholelithiasis: gives good accuracy and can detect different types of stones at different locations compared to ultrasound
CT sonogram
Created by stones in the gallbladder that are right beside each other
Mercedes Benz sign
Press the inferior portion of the liver, and if there is inspiratory arrest, this is positive
Murphy’s sign
Ask the patient to place their hand on back, thumbs up
Radiation of pain to inferior scapula
Collin’s sign
Filling defects at the distal segments of the esophagus > represents erosion secondary to reflux
X-ray with contrast
Caused by corrosion, infection, radiation therapy
Esophageal atresia
EA is confirmed by
Barium enema
Achalasia
Abnormal distension of entire esophagus then abrupt tapering distally
Failure of lower esophageal sphincter to relax
Possible defect: auerbach’s plexus, vagus nerve, dorsal motor nucleus of the vagus nerve
Bird’s beak/rat’s tail sign
Complication of achalasia
Secondary to chronic esophageal irritation
Esophageal cancer
Diagnosing using esophagogram
Outpouching containing contrast
Diverticulum
Proximal
Between cricopharyngeus and inferior pharyngeal sphincter muscles
Zenker’s diverticulum
Distal
Above the lower esophageal sphincter, more frequently on the right
Epiphrenic diverticulum
Linitis plastica
Persistently narrow, not distensible bowel walls
May indicate serous adenocarcinoma
Old leather water bottle
Intramural hemorrhage
Secondary to scleroderma, malabsorptive gastroenteropathies, vasculitis, trauma, coagulation defects, ischemia
Asymmetric atrophic longitudinal layer
Stack of coins
Colon constriction
Abnormally constricted segment of sigmoid colon
Not distensible despite inflation with air
Demonstrated with air
May be due to mechanical small bowel obstruction, foreign bodies, tumors, chrohn’s disease, ulcerative colitits, adhesions, herniais, volvulus
Apple core deformity
Contrast containing segment of the bowel loop that appears narrow or stenotic
Caused by Crohn’s disease, radiation enteritis, lymphoma, endometriosis, eosinophilic gastroenteritis, drug-induced, ulcerative colitis
Bowel stenosis
Intermittent abdominal pain, previous travel to a developing country
Coral look > valvulae conniventes
Commonly at the jejunal segment
Ascariasis
Gas-filled distension of bowels
Distal portion of intestinal tract
Absence of ganglionic cells in the distal colon or functional obstruction
Hirschprung disease/aganglionic megacolon
Seemingly normal
Cecum is not in its normal position
Normal embryological process of bowel fixation and development is interrupted
Malrotation
Acquired herniations of the mucosa and portions of the submucosa through the muscularis propria
Round opacities outline the colon walls
Diverticulosis
Iodinated contrast
Hepatobiliary tree
Abnormally distended commno bile duct + dilated radicles
5 types
Choledochal cyst
Most common type
Fusiform dilatation of extrahepatic duct
Type 1
Diverticulum along the common bile duct
Type 2
Choledochocele
Outpouching inside the duodenum
Type 3
Intrahepatic and extrahepatic ducts are dilated
Second most common
Type 4
Intrahepatic ducts are dilated
Caroli’s disease
Type 5
Modality of choice for the imaging of the hepatobiliary tree
For viewing of the intestines
Confirm disease of the intestinal tract
Appendicitis
UTZ
Distension of small bowels
Fluid-filled bowel loops
Presence of anechoic areas in affected bowel segments
Ileus
Blind ended tubular structure
Trilaminated wall with targetoid appearance
Appendicolith
Acute appendicitis
Hyperchoic focus at the tip of the appendix
Calcified deposit of material within the appendix
Appendicolith
Abnormal telescoping of one segment into another
Palpable sausage-like mass lesion
Intussusception
Intussusception signs on transverse cut
Target sign
Bull’s eye
Crescent-in-doughnut
Intussusception signs on longitudinal cut
Pseudokidney
Hayfork sign
Bull’s eye
Most common location of intussusception in pedia
Ileocecal
Protrusion of contents of the abdominal cavity through the inguinal canal
Inuinal hernia
In CT scan, the landmarks of hernia
Hesselbach’s triangle
- base: inguinal ligament
- lateral: epigastric artery
- medial: rectus sheath
Landmarks of direct hernia
Enters within Hesselbach’s triangle
Landmarks of indirect hernia
Enters at the deep ring > inguinal canal > upper pole of testis
Echogenic structure same as surrounding tissues
Antenatal ultrasound can diagnosis this
Anterior abdominal wall defect through which abdominal contents freely protrude
Gastrochisis
Organs remain enclosed in visceral peritoneum
Omphalocele
Increased echogenicity of the liver
Reversible, multifactorial disease, due to improper diet/alcoholism
Fatty liver
Accumulation of fluid in the peritoneum
Secondary to many etiologies
Appears as anechoic areas in spaces between organs
Ascites
Ascites in hepatorenal space
Morrison’s pouch
Well-circumscribed anechoic focus in the liver parenchyma
Can’t determine if benign or malignant on UTZ
Livery cyst/nodule
Upper limits of normal size on UTZ
Length: 12 cm
Width: 7 cm
Height: 5 cm
Anechoic
Splenic vein, aorta, IVC, celiac artery
Pancreas/ pancreatic cyst
Distendeded gall bladder (> 10 x 5 x o,3)
Cholecystitis
Types of cholecystitis
Calculous (with stones)
Acalculous (no stone)
Stones in the gallbladder appear hyperechoic on an anechoic background
Stones are round, well-circumscribed foci with posterior shadowing
Cholelithiasis
Can demonstrate exact site of obstruction
To check for abnormal gas pattern
To determine the cause of obstruction
Abnormal fluid collection
CT Scan
On CT, thickened bowels hyperdensities
On XR, apple core deformity
Colon constriction
Round structure with contrast outside: diameter is thickened, air and inflammation, appendicitis
Soft tissue lesions
Stone enters intestinal tract
Gallbladder ileus
Heterogenous pancreas
Hypodensities which enhance with contrast
Acute pancreatitis
Using CT for prognostication
Balthazar score
Abnormal fluid collection at tail of pancrease
Creates colon cut-off sign
Abscess formation
Better demonstrates the cause of the obstruction
CT scan
On lateral side of abdominal wall
Spigelian hernia
Similar to standard/rigid colonoscopy but invasive
Bowel preparation and lying down are rquired
Virtual colonoscopy/CT colonoscopy
Confirmatory examination in pregnancy, history of allergic reaction to contrast material
Equivocal findings in CT
MRI
Pattern of contrast would make one lesion more unique than the other
Liver nodules
Mass lesions in liver
Plaques
Filling defects
Gallbladder stone
Isolate the biliary tract and reconstruct the image
Filling defects = stones
Static fluid = bright against low signal
Requires no contrast
MR cholangiopancreatography
Indicated in pregnant
Hyperintense signal surrounded by hypointense backgound on T2
Appendicitis
Indicated in those who have allergic reactions to contrast, renal failure
Hyperintense
Pancreatitis
