Dr. Kelsey Lena is an Emergency Medicine Resident and Drs. Michael Avery and Joshua Davis are Surgery Residents at Carolinas Medical Center in Charlotte, NC. They are interested in medical education. With the guidance of Drs. Kyle Cunningham and Michael Gibbs, they aim to help augment our understanding of emergent abdominal imaging. Follow along with the EMGuideWire.com team as they post these monthly educational, self-guided radiology slides. This month’s topics include: • Emphysematous cholecystitis • Pyelonephritis • Perinephric abscess

1. Adult Abdominal Imaging Case Studies
Michael Avery, DO, Joshua Davis, MD, Kelsey Lena, MD
Department of Surgery & Emergency Medicine
Carolinas Medical Center & Levine Children’s Hospital
Kyle Cunningham, MD & Michael Gibbs MD - Faculty Editors
Abdominal Imaging Mastery Project
March 2021

2. Disclosures
▪ This ongoing abdominal imaging interpretation series is proudly co-
sponsored by the Emergency Medicine & Surgery Residency Programs
at Carolinas Medical Center.
▪ The goal is to promote widespread interpretation mastery.
▪ There is no personal health information [PHI] within, and ages have been
changed to protect patient confidentiality.

3. Process
▪ Many are providing cases and these slides are shared with all contributors.
▪ Contributors from many Carolinas Medical Center departments, and now…
Brazil, Chile and Tanzania.
▪ Cases submitted this month will be distributed next month.
▪ When reviewing the presentation, the 1st slide will show an image without
identifiers and the 2nd slide will reveal the diagnosis.

4. It’s All About The Anatomy!

5. Systematic Approach to Abdominal CTs
● Aorta Down - follow the flow of blood!
○ Thoracic Aorta → Abdominal Aorta → Bifurcation → Iliac a.
● Veins Up - again, follow the flow!
○ Femoral v. → IVC → Right Atrium
● Solid Organs Down
○ Heart → Spleen → Pancreas → Liver → Gallbladder → Adrenal
→ Kidney/Ureters → Bladder
● Rectum Up
○ Rectum → Sigmoid → Transverse → Cecum → Appendix
● Esophagus down
○ Esophagus → Stomach → Small bowel

6. Systematic Approach to Abdominal CTs
● Abdominal Wall/Soft tissue Up
○ Free air, abscesses, hernias
● Retroperitoneum Down
○ Hematoma, masses
● GU Up
○ Masses
● Tissue specific windows
○ Lung
○ Bone
● Don’t forget to look at multiple planes
○ Axial, sagittal, coronal

7. CBD
SMV
SMA
duodenum
Portal vein
CBD and PD
CASE:
Patient is a 49-year-old
male with 2 days of acute
abdominal pain and 2-3
months of right upper
quadrant pain on and off.
Nausea and vomiting are
present on presentation.
Diagnosis?

8. CBD
SMV
SMA
duodenum
Portal vein
CBD and PD
CASE:
Patient is a 49-year-old
male with 2 days of acute
abdominal pain and 2-3
months of right upper
quadrant pain on and off.
Nausea and vomiting are
present on presentation.
Diagnosis?
Emphysematous
cholecystitis with
possible
cholecystoduodenal
fistula.
Possible
Cholecystoduodenal
Fistula
Gas And Air
Surrounding And
Within The
Gallbladder

9. Emphysematous Cholecystitis
• Uncommon variant of acute cholecystitis with presence of gas in the
gallbladder lumen or wall or in the pericholecystic fluid
• Associated with gas-forming bacteria including Clostridium perfringens,
Klebsiella species and Escherichia coli
• Surgical emergency due to increased mortality (reported up to 15%)
• More common in men
• Patients usually in 50’s or 60’s and have a history of diabetes mellitus

10. Radiographic Features of Emphysematous
Cholecystitis
• Air in the gallbladder wall +/- biliary ducts
• Ultrasound may show “Champagne Sign”
• Multiple small echogenic foci migrating from dependent to non-
dependent position within the gallbladder as the patient changes
their position
• Pathognomonic for gas in the gallbladder
• CT is most sensitive and specific imaging
• Gas will be seen in the gallbladder lumen or wall

11. Radiographic Features of
Emphysematous
Cholecystitis
Champagne Sign

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16. Treatment of Emphysematous Cholecystitis
• Surgical emergency
• Emergent cholecystectomy is recommended
• Percutaneous cholecystostomy tube can be placed as a temporizing
measure in patients who are too unstable for surgery
• Patient must also be evaluated for possible cholecystoduodenal
fistulas
• Fistula connection between the gallbladder and duodenum
• Most common type of enterobiliary fistula

19. CASE:
The patient is a 19-year-
old women who presents
with fever to 101ºF,
abdominal pain, nausea,
and vomiting. She has
positive right sided flank
tenderness without
dysuria or urinary
frequency.
WBC of 21,000.
Urinalysis with pyuria,
hematuria, [+] bacteria,
[+} leukocyte esterase.
Diagnosis?

20. Diagnosis:
Acute right-sided
pyelonephritis.
Differential Renal
Enhancement
Retroperitoneal
Perinephric Fat
Stranding

21. Pyelonephritis
• Classic triad of fever, flank pain, nausea and emesis
• Dysuria not always present and in patient with above symptoms,
supportive lab findings, and suggestive CT findings pyelonephritis should
be presumptive diagnosis
• Consider broad differential: appendicitis, ruptured ectopic pregnancy,
kidney stones, abdominal abscess, etc
• Differential renal enhancement when comparing kidneys AKA “delayed
nephrogram” may be seen
• Striated nephrogram may also been seen characterized as striping pattern
across renal parenchyma

22. CASE:
The patient is a 72-year-
old male with a history of
benign prostatic
hyperplasia, diabetes
mellitus, and
hypertension who
presents to the ED
hypotensive, tachycardic,
and febrile with
complaint of worsening
back pain and chills.
Exam notable for diffuse
abdominal tenderness.
Diagnosis?

23. CASE:
The patient is a 72-year-
old male with a history of
benign prostatic
hyperplasia, diabetes
mellitus, and
hypertension who
presents to the ED
hypotensive, tachycardic,
and febrile with
complaint of worsening
back pain and chills.
Exam notable for diffuse
abdominal tenderness.
Diagnosis?
Left Perinephric Abscess
Appreciate The Large
Lobulated/Loculated Left Perinephric
Fluid Collection, Ultimately Distorting
The Left Renal Parenchyma

24. Perinephric Abscess
• Results from perirenal fat necrosis between the renal capsule and Gerota’s
fascia
• More than 75% of perinephric abscesses are due to complications of
urinary tract infections
• Most common organisms: Escherichia coli, Klebsiella pneumonia
• Different etiologies in patients with prolonged bacteremia (hematogenous
seeding), most notably from Staphylococcus aureus
• The average duration of symptoms (fever, chills, abdominal pain,
anorexia, and dysuria) before admission is ≈12 days

25. Risk Factors
• Diabetes
• Pregnancy
• Structural abnormalities:
• Nephrolithiasis
• Vesiculoureteral reflux
• Polycystic kidney disease
• Obstructing renal tumor
Clinical Presentation
• Nonspecific
• Fever + chills most common
• Flank & abdominal pain
• Leg/groin pain when the
infection tracks downwards via
fascial plains (i.e.: psoas abscess)
Perinephric Abscess

26. Fascial Plains In The Abdomen & Retroperitoneum.

27. Fascial Plains In The Retroperitoneum.

28. Perinephric
Abscesses

29. Psoas
Abscesses

30. Perinephric Abscess Treatment
<3 cm Antibiotic therapy
>3 cm Percutaneous catheter drainage + antibiotics
Large1 Surgical drainage
Structural Abnormalities2 Surgical drainage
1Too large for effective percutaneous catheter drainage.
2Structural abnormalities increase the likelihood of treatment failure with “standard” therapy.
Staph. aureus Vancomycin (MRSA); Nafcillin + gentamycin (MSSA)
Enterococcus Ampicillin + gentamycin
Oral Agents Ciprofloxacin; levofloxacin; bactrim DS

31. Summary Of Diagnoses This Month
● Emphysematous cholecystitis
● Pyelonephritis
● Perinephric abscess

32. See You Next Month!