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10/12/20151
Abdominal Imaging9 topics in 90 min
10/12/2015
Antonio C. Westphalen, MD PhDDepartments of Radiology and Biomedical Imaging, and Urology
Outline
Brief description of the problem
Imaging options
• advantages and disadvantages
• main imaging findings
Additional imaging
• further characterization
• follow-up
Focus on most common problems faced by the hospitalist
10/12/2015Abdominal Imaging - 9 Topics in 90 min2
Liver Biliary tree Gallbladder Pancreas Kidneys Small bowel Colon Abscess? Tubes and lines
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10/12/20152
Liver
Obese patient
Elevated liver enzymes
RUQ pain
Non-alcoholic steatohepatitis? / cirrhosis?
Non-alcoholic fatty liver disease
10/12/20153 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
NALFD vs cirrhosis
Ultrasound
Computed tomography
Magnetic resonance imaging
Steatosis may be diffuse or focal; and it is a heterogeneous process.
Non-alcoholic steatohepatitis cannot be diagnosed with imaging.
Cirrhosis: morphologic changes and evidence of portal hypertension.
Imaging options
10/12/20154 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Imaging options
Usually the first option when NAFLD is suspected
Inexpensive, safe, readily available on the bed side, and highly accurate
Full assessment of the parenchyma may be limited in severe cases.
Hepatomegaly
echogenicity / smooth vs nodular (split image of spleen – use same setup)
Poor visualization of deep parts of the liver
Ultrasound
10/12/20155 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Imaging options
Usually best in advanced disease with suspected cirrhosis
Non-contrast CT for steatosis, contrast-enhanced for cirrhosis (GFR>45)
Radiation exposure
Low density compared with spleen on non-contrast CT (difference > 10 HU)
Cirrhosis: nodular contour, widened gallbladder fossa, large caudate
Portal hypertension: large PV (> 12-15mm), collaterals, splenomegaly, ascites
Classical HCC are hypervascular lesions that washout on the delayed phase.
Computed tomography
10/12/20156 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Imaging options
Option to CT when suspect cirrhosis
Best to characterize atypical/focal steatosis or indeterminate liver nodules
In general, more sensitive than US and CT to detect fat
Longer scan, breath holds, susceptible to artifacts (e.g. motion of ascites)
In- and out-of-phase imaging
If suspect cirrhosis, better to use gadolinium (contraindicated if GRF<30)
Magnetic resonance imaging
10/12/20157 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Biliary tree
Patient with cholestasis
Elevated bilirubin, direct > indirect
Elevated alkaline phosphatase
Borderline elevated AST and ALT
Intra- or extrahepatic obstruction?
Cause?
Biliary obstruction
10/12/20158 Abdominal Imaging - 9 Topics in 90 min
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Intra- or extrahepatic obstruction? Cause?
Ultrasound
Computed tomography
Magnetic resonance imaging
Extrahepatic obstruction is suggested by the presence of dilated ducts
Normal ducts do not exclude acute/new or intermittent obstruction.
Double duct sign (biliary and pancreatic ducts): pancreas, ampulla, scarring
Imaging options
10/12/20159 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Imaging options
Always the first option for the assessment of bile ducts and gallbladder
Inexpensive, safe, readily available on the bed side, and highly accurate
May not detect the specific cause and level of obstruction. Bowel gas may obscure visualization of the CBD. Limited in markedly obese individuals.
Try to always use the liver as a window to visualize the entire biliary tree
Change decubitus/position to move air away from the area of interest
Sometimes water PO helps
Ultrasound
10/12/201510 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Imaging options
Better than US to determine the specific cause and level of obstruction.
Visualizes the liver parenchyma more consistently than US.
Very limited for CBD stones – most are radiolucent. Radiation (40-50 years old). More expensive than US.
Good option when a tumor is suspected
IV contrast helps to determine the cause (late arterial & portal venous phases)
Planning of percutaneous drainage
Computed tomography
10/12/201511 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Imaging options
MRI for parenchyma / MRCP for ducts
MRCP – noninvasive and sensitive to detect stones, strictures, or dilatations.
Requires good breath holds, fluid in the duodenum or ascites usually cause artifacts and limit visualization of ducts with MRCP.
Good option when a CBD stone is suspected, but not visualized with US
Option when tumor is suspected & iodinated contrast contraindicated (allergy)
Best option when tumor is suspected & IV contrast contraindicated (low GFR)
Magnetic resonance imaging + MR cholangiopancreatography
10/12/201512 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Additional imaging
Diagnostic and therapeutic modality
Imaging and sampling / removal of stones, stents, drains, & sphincterotomy
Limited visualization of bile ducts proximal to the obstruction. Complications (10% risk overall, most commonly pancreatitis)
Standard of reference (high accuracy and excellent spatial resolution)
Best for obstruction at or distal to the confluence of right and left ducts
Consider EUS (+/- FNA) if distal CBD tumor is suspected but not seen by other methods
Endoscopic retrograde cholangiopancreatography (ERCP)
10/12/201513 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Remember!
Mild central intrahepatic and CBD dilatation in older patients …
… and after cholecystectomy
Biliary ductal dilatation of no clinical significance
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Gallbladder
Biliary colic / acute RUQ pain / Murphy sign
Nausea / vomiting
+/- fever
Leukocytosis / mild cholestasis
Confirm diagnosis and determine cause
Complications?
Acute cholecystitis
10/12/201515 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Acute cholecystitis? Cause? Complications?
Ultrasound
Computed tomography
Distension of the gallbladder, gallbladder wall thickening, pericholecystic fluid, and gallstones suggest the diagnosis.
Biliary sludge and gallbladder wall thickening without distension and pericholecystic fluid are commonly seen with chronic illnesses.
Ascitic fluid versus pericholecystic fluid
Imaging options
10/12/201516 Abdominal Imaging - 9 Topics in 90 min
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Imaging options
Always the first option for the assessment of bile ducts and gallbladder
Inexpensive, safe, readily available on the bed side, and highly accurate
Ultrasonographic Murphy sign
Thick GB walls or pericholecystic fluid? Turn Doppler on and look for vessels!
Are GS mobile? Change decubitus. An impacted stone increases the probability of acute cholecystitis.
Ultrasound
10/12/201517 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Imaging options
Best option for assessment of complications
May identify extrabiliary causes of acute cholecystitis
Use of IV contrast is recommended
Perforation: decompressed GB, pericholecystic fluid, hyperemia liver tissue
Pancreatitis
Abscess
Computed tomography
10/12/201518 Abdominal Imaging - 9 Topics in 90 min
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Additional imaging
Equivocal US results or acalculus cholecystitis
Opacification of the gallbladder excludes the diagnosis
Failure to fill the gallbladder suggests acute cholecystitis
FP results: TPN or prolonged NPO, severe liver disease, sphincterotomy
Cannot assess most complications
Cannot assess alternative diagnoses
HIDA cholescintigraphy, or HIDA scan
10/12/201519 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Pancreas
Acutely ill, hypotensive / tachycardic
Upper / epigastric pain radiating to back
Nausea / vomiting
Elevated amylase & lipase / leukocytosis
Diagnosis?
Stage? Complications?
Cause? (uncommonly)
Pancreatitis
10/12/201520 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Diagnosis? Stage? Complications? Cause?
Computed tomography
Magnetic resonance imaging
Usually not indicated if no signs of severe pancreatitis or rapid improvement.
The ideal time to assess complications is 72 hours after onset of symptoms.
To exclude cancer in patients > 40 yo with first episode of pancreatitis without identifiable cause
Imaging options
10/12/201521 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Imaging options
Primary imaging tool to assess patients with pancreatitis
Part of the revised Atlanta classification as a diagnostic criteria
Also useful to guide percutaneous drainages or other interventions
IV contrast is required – pancreatic protocol (noncon, arterial, portal venous)
Interstitial edematous pancreatitis versus necrotizing pancreatitits
Pancreatic and peripancreatic collections
Computed tomography
10/12/201522 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Interstitial edematous versus necrotizing pancreatitits
Localized or diffuse enlargement
Normal homogeneous or slightly heterogeneous enhancement (edema)
Normal or mild inflammation of the peripancreatic tissues
Marked heterogeneous enhancement within the first 5-7 days of onset could be IEP or ill-defined necrosis. CT performed after 5–7 days permits definitive characterization.
Interstitial edematous pancreatitis
10/12/201523 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Interstitial edematous versus necrotizing pancreatitits
Parenchymal necrosis alone: < 5%
Peripancreatic necrosis alone: ≅ 20%
Parenchymal and peripancreatic necrosis: ≅ 75-80%
Lack of enhancement on contrast-enhanced CT a week after onset
Less than 30% and greater than 30%
Heterogeneous areas with lack of enhancement that contain nonliquefiedcomponents
Necrotizing pancreatitis
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Pancreatic and peripancreatic fluid collections
Acute necrotic collection 4 weeks walled-off necrosis
Acute peripancreatic fluid collection 4 weeks pseudocyst
Sterile or infected
Acute: conform to the anatomic boundaries and have no discernable wall
Chronic: round or oval surrounded by a well-defined enhancing wall
Infection: diagnosed by the presence of gas (in the absence of GI tract fistula)
Pancreatic collections
10/12/201525 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Imaging options
Suspected choledocholithiasis not yet visualized
Characterize collections - nonliquefied material may mimic fluid of CT
CT is contraindicated (eg, allergy to iodinated contrast or pregnancy)
Cost and availability
Accuracy MRI = CT
CT is used to guide procedures
Magnetic resonance imaging
10/12/201526 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Additional imaging
Gallstones and/or choledocholithiasis
Guide drainage of collections
Vascular assessment (venous thrombosis / pseudoaneurysms)
Ultrasound
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Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Chronic pancreatitits
Parenchymal atrophy, PD dilatation and calcifications (CT only)
Acute on chronic? Peripancreatic fluid/necrosis > parenchymal findings!
Pancreatic cancer?
Stenosis of the duct?
Computed tomography and magnetic resonance imaging
10/12/201528 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Adrenals
Incidental findings
Associate with endocrine symptoms
Subclinical with hormonal imbalances
Known primary cancer
Diagnosis?
Nest step?
Adrenal nodules
10/12/201529 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Diagnosis? Next step?
Computed tomography
Magnetic resonance imaging
The goal of imaging is to characterize and adenoma versus a nonadenoma
Dx of adenomas: intracytoplasmatic lipid and/or enhancement characteristics
1/3 of adenomas are lipid-poor
Imaging options
10/12/201530 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Imaging options
Primary imaging tool to diagnose adenomas
Adrenal protocol: unenhanced CT plus/minus PV & delayed phases (≅12 min)
Imaging guided biopsy
Low density (< 10-15 HU) on unenhanced CT: very high specificity and PPV
Contrast washout characteristics (40% to 60% on delayed phase)
Computed tomography
10/12/201531 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Imaging options
Generally used to characterize indeterminate lesions on CT
Detection of microscopic lipid
Breath holding, not useful if unenhanced CT density > 30 HU
Relative signal loss from in-phase to out-of-phase images
Virtually diagnostic of adenoma
Magnetic resonance imaging
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Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Additional imaging
Reserved for patients with known primary cancer to exclude metastasis
Indicated to investigate of masses > 4 cm, in lieu of biopsy
Meta-analysis (patients with known primary cancer):
Sensitivity = 97% / Specificity = 91%
⊕ LR = 11.1 / ⊖ LR = 0.04
PET-CT
10/12/201533 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Beware!
Metastases of renal cell carcinoma may have washout equivalent to adenomas
Metastases of hepatocellular carcinoma may have microscopic fat
Magnetic resonance imaging
10/12/201534 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Computed tomography
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Kidneys
Flank pain / renal colic
Hematuria
History of urolithiasis
Diagnosis
Obstruction? Probability stone passage?
Complications?
Urolithiasis
10/12/201535 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Urolithiasis
Ultrasound
Computed tomography
KUB
Consider history of urolithiasis and characteristics of symptoms
Consider patient’s age (radiation exposure)
Consider pre-test probability of alternative diagnosis
Imaging options
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Imaging options
Possibly the first option if known urolithiasis and classical symptoms
Inexpensive, safe, readily available on the bed side
Limited assessment of midureter due to gas in the GI tract
Hydronephrosis
Scan pelvis with bladder slightly full to better visualize distal ureter and UVJ
Change patient decubitus to move gas / slow and continue pressure
Ultrasound
10/12/201537 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Imaging options
First option if nonclassical symptoms and need to exclude other causes of pain
Visualizes virtually all stones, sensitivity ≅ 90%
Radiation exposure – young patients with repeated episodes of renal colic
Noncontrast CT suffices in the vast majority of cases / IV if no urolithiasis
Scan prone to more completely assess UVJ stones
6 mm threshold (axial plane) for spontaneous passage
Computed tomography
10/12/201538 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Ultrasound or computed tomography?
10/12/201539 Abdominal Imaging - 9 Topics in 90 min
Westphalen AC. Acad. Emerg. Med. 2011 Jul;18(7):699-707
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Ultrasound or computed tomography?
10/12/201540 Abdominal Imaging - 9 Topics in 90 min
Westphalen AC. Acad. Emerg. Med. 2011 Jul;18(7):699-707
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Ultrasound or computed tomography?
10/12/201541 Abdominal Imaging - 9 Topics in 90 min
Smith-Bindman R. N Engl J Med 2014; 371:1100-1110
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Imaging options
Option to assess passage of stones after treatment (PNL of staghorn calculus)
Easy to obtain in the bed side, little radiation
Limited for the initial assessment of suspected urolithiasis
• overlap of bowel content and bones
KUB
10/12/201542 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Additional imaging
Rarely used nowadays
Intravenous pyelography
10/12/201543 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Complications
Calyceal rupture is a minor complication, usually treated with stenting
Contrast-enhanced CT (delayed/excretory phase)
Pyonephrosis is a medical emergency and requires immediate drainage
Limited renal ultrasound
Interventional radiology
Calyceal rupture and pyonephrosis
10/12/201544 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Small bowel
Abdominal distension / pain
Nausea / vomiting
History of abdominal surgery
Diagnosis?
If SBO, cause?
Management?
SBO versus ileus
10/12/201545 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
SBO vs ileus
Computed tomography
KUB
Initial assessment = computed tomography
KUB may be an option for follow-up
Imaging options
10/12/201546 Abdominal Imaging - 9 Topics in 90 min
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Imaging options
Better first option for initial assessment of suspected SBO
Fast, more sensitive than KUB, identifies a cause in ~ 80% of cases
IV contrast (nonadhesive causes), PO contrast (transition point)
SBO = proximal dilated loops of SB (> 3 cm), decompressed distally (RLQ)
Ileus = diffuse distention, often borderline, normal stool/air in colon
SBO in developed countries = adhesions (> 2/3 of cases)
SBO in developing countries = incarcerated hernias (up to 80% of cases)
Computed tomography
10/12/201547 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Imaging options
May be used for follow-up of patients with SBO
50-60% sensitive for SBO, does not identifies cause of SBO
Abdominal series (at least one standing or left lateral decubitus)
SBO = air fluid levels at various heights, central predominance, with paucity of gas distally and in colon
SBO = gasless abdomen if dilated and fluid filled SB, or after vomiting
Ileus = borderline dilatation with air found throughout SB and in colon
KUB
10/12/201548 Abdominal Imaging - 9 Topics in 90 min
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Additional imaging
Not for diagnostic use
Predict the need of surgery and (?) shortens the course of partial SBO
Usually done 48 hours after unsuccessful conservative therapy
Contrast reaches the colon in 4-6 hours = conservative treatment
Contrast does not reach the colon in 12 hours = surgery
KUB with PO Gastrografin (Diatrizoate Meglumine)
10/12/201549 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Closed loop obstruction
25% risk of strangulation and infarction
Marked segmental distension of bowel, often C or U shape
"beak sign": tapering bowel loops at the point of obstruction
”whirl": tightly twisted mesentery
Contrast enhanced CT, due to high risk of ischemia and infarction
Computed tomography
10/12/201550 Abdominal Imaging - 9 Topics in 90 min
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Bowel ischemia
Imaging appearance similar independent of cause
Unenhanced, late arterial phase, and portal venous phase of enhancement
Contrast enhanced CT due to high risk of ischemia and infarction
Wall thickening and free fluid
Hyperemia or decreased enhancement of wall
Pneumatosis intestinalis, pneumoperitoneum, pneumatosis portalis
Computed tomography
10/12/201551 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Colon
Diarrhea, fever, abdominal pain
Abdominal distension
Leukocytosis
Broad-spectrum antibiotic use
Diagnosis?
C. difficile colitis? Or another cause?
Complications?
Pseudomembranous colitis
10/12/201552 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Diagnosis? Complications?
Computed tomography
KUB
Colonic distension
(Diffuse) marked wall thickening, “thumbprinting”
Toxic megacolon (perforation)
Imaging options
10/12/201553 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Imaging options
More sensitive option for the diagnosis of colitis and its complications
Etiology is suggested, but not necessarily definitively established
Sensitivity and specificity approximately 85% and 48% (colonic abnormalities)
IV contrast, no PO contrast
(Diffuse) marked wall thickening, “thumbprinting”
Paucity of pericolonic inflammation may help differentiate from other colitides
Computed tomography
10/12/201554 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Imaging options
Easy and quick exam, but normal early in the disease
Useful for follow-up (q 12-24h); may identify development of toxic megacolon
Bowel dilatation, mural thickening and thumbprinting on more advanced cases
Underestimate the severity of disease
Limited for detection of small pneumoperitoneum
Abdominal series preferable to KUB
KUB
10/12/201555 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Additional imaging
Limited role in the diagnosis
Contraindicated in patients with severe (perforation)
Barium enema
10/12/201556 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Toxic megacolon
Nonobstructive colonic dilatation plus systemic toxicity
Marked distension > 6 cm transverse segment
Loss of hautral markings, pseudopolyps, and air-fluid levels
Risk of perforation high if cecum > 12 cm
Ischemia
Pneumoperitoneum
KUB or CT
10/12/201557 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Remember!
Must consider the clinical setting
Interpretation of scans is improved with adequate history
Imaging findings often not specific for a particular etiology
10/12/201558 Abdominal Imaging - 9 Topics in 90 min
Song KS. Yonsei Med J. 1992 33(2):168-72.
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Abscess
Post operative/trauma/infection/inflammation
1 to 3 weeks to develop
Fever, abdominal pain, anorexia
Nausea, ileus, weight loss
Leukocytosis
Diagnosis
Treatment planning
10/12/201559 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Diagnosis? Treatment planning?
Computed tomography
Ultrasound
Walled-off collection
Amenability to percutaneous drainage
Exclude associated complications, e.g. venous thrombosis
Imaging options
10/12/201560 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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Imaging options
Primary imaging modality (diagnosis and drainage)
IV (diagnosis) and oral contrast (drainage) are helpful
Collection with enhancing walls and mass effect
(Complex) fluid attenuation
Presence of gas is the most specific finding
Adjacent inflammatory findings (fat stranding/fluid)
Computed tomography
10/12/201561 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Imaging options
Easy, fast, and cheap to perform in the bedside
Better for superficial, rather than deep abscesses
Operator dependent
Collection with thick walls and flow on color Doppler
Complex fluid (floating echos)
Gas is the most specific finding (echogenic and mobile foci with dirty shadow)
Turn on color Doppler to find vessels prior to any percutaneous interventions
Ultrasound
10/12/201562 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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10/12/201532
Additional imaging
Equivocal US and CT results
Elaborate procedure, requires strict patient collaboration
½ of abscesses are identified by 4 h after injection, more than 90% by 24 h
FP results: interpretation must refer to CT findings
FN results: chronic abscess (> 3 weeks); lymphocytic mediated infection, e.g. TB or other granulomatous processes; abscess in or adjacent to liver or spleen
111In-leukocyte scintigraphy ?
10/12/201563 Abdominal Imaging - 9 Topics in 90 min
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
Thank You!
antonio.westphalen@ucsf.edu
Liver Biliary tree Gallbladder Pancreas Adrenals Kidneys Small bowel Colon Abscess?
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