# Clinical Cases: Abdominal Imaging

## Case 1: Small Bowel Obstruction

### Patient Demographics
- **Age:** 62 years
- **Sex:** Female

### Chief Complaint
Abdominal pain, distension, and vomiting for 2 days

### Presenting Symptoms
The patient presents with progressive crampy abdominal pain that began 2 days ago. She reports abdominal distension, nausea, and multiple episodes of bilious vomiting. She has not passed flatus or had a bowel movement in 36 hours. Her surgical history includes an open appendectomy 25 years ago and a cesarean section 30 years ago.

### Physical Exam Findings
- **Vital Signs:** BP 118/74 mmHg, HR 98 bpm, RR 18/min, Temp 37.2C
- **General:** Uncomfortable appearing, lying still
- **Abdomen:** Distended, tympanic to percussion, diffuse tenderness without peritoneal signs, high-pitched bowel sounds with occasional rushes, well-healed lower midline and McBurney's point scars
- **Rectal Exam:** Empty rectal vault, no masses

### Imaging Findings and Interpretation
**Abdominal Radiograph (Supine and Upright):**
- Multiple dilated small bowel loops (>3 cm diameter)
- Valvulae conniventes visible extending across the full lumen width
- Multiple air-fluid levels at different heights within the same loop (upright)
- Paucity of colonic gas
- "String of pearls" sign - small trapped air bubbles in a row within fluid-filled obstructed loops
- No pneumoperitoneum on upright view

**CT Abdomen/Pelvis with IV Contrast:**
- **Transition Point:** Identified in the right lower quadrant, where dilated proximal small bowel (up to 4.5 cm) meets decompressed distal bowel
- **Cause:** Band adhesion visible at the transition point causing sharp angulation of the bowel
- **Small Bowel Feces Sign:** Present in the dilated ileum, indicating chronic/subacute obstruction
- **Bowel Wall:** Normal wall thickness and enhancement throughout; no evidence of ischemia
- **Mesentery:** No stranding or haziness to suggest strangulation
- **No closed loop:** Single transition point without evidence of two-point obstruction
- **Free Fluid:** Minimal physiologic fluid in the pelvis

**Key Interpretation:**
The findings are consistent with complete small bowel obstruction due to adhesive band from prior surgery. The absence of bowel wall thickening, abnormal enhancement, mesenteric haziness, or pneumatosis indicates no current signs of strangulation or ischemia.

### Diagnosis
Complete small bowel obstruction secondary to adhesive band; no evidence of strangulation

### Management
1. NPO status with nasogastric tube decompression
2. IV fluid resuscitation with correction of electrolyte abnormalities
3. Foley catheter for strict monitoring of urine output
4. Serial abdominal examinations every 4-6 hours
5. Trial of non-operative management for 24-48 hours given no signs of strangulation
6. Repeat CT if clinical deterioration or failure to improve
7. Surgical consultation with plan for operative intervention if:
   - Peritoneal signs develop
   - Fever or leukocytosis suggesting ischemia
   - Failure to resolve with conservative management by 48-72 hours

### Radiological Image

![Small Bowel Obstruction CT](case_01_image.jpg)

**Image Description:** CT scan demonstrating small bowel obstruction with dilated proximal loops and a clear transition point where the bowel caliber changes from dilated to decompressed. The small bowel feces sign is visible in the dilated loops.

**Source:** Wikimedia Commons - "CT scan showing small bowel obstruction"
**URL:** https://commons.wikimedia.org/wiki/File:Upright_abdominal_X-ray_demonstrating_a_small_bowel_obstruction.jpg
**License:** Creative Commons Attribution-Share Alike 3.0 Unported

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## Case 2: Acute Cholecystitis

### Patient Demographics
- **Age:** 48 years
- **Sex:** Female

### Chief Complaint
Severe right upper quadrant pain for 12 hours

### Presenting Symptoms
The patient presents with sudden onset severe right upper quadrant pain that began after eating a fatty meal the previous evening. The pain is constant, radiates to the right shoulder, and is associated with nausea and multiple episodes of non-bilious vomiting. She reports similar but less severe episodes over the past year that resolved spontaneously. Risk factors include obesity, multiparity, and a family history of gallstones.

### Physical Exam Findings
- **Vital Signs:** BP 142/88 mmHg, HR 94 bpm, RR 18/min, Temp 38.1C
- **General:** In obvious discomfort, unable to find comfortable position
- **Abdomen:** Significant tenderness in right upper quadrant, positive Murphy sign (inspiratory arrest with palpation of the gallbladder), mild guarding, no rebound tenderness, no palpable mass
- **Laboratory:** WBC 14,200/uL, Total bilirubin 1.8 mg/dL, ALT 62 U/L, AST 48 U/L, Lipase normal

### Imaging Findings and Interpretation
**Right Upper Quadrant Ultrasound:**
- **Gallbladder:** Distended with multiple mobile echogenic foci with posterior acoustic shadowing (gallstones)
- **Impacted Stone:** Large stone (1.8 cm) lodged in the gallbladder neck
- **Wall Thickening:** Gallbladder wall measures 5 mm (abnormal >3 mm)
- **Pericholecystic Fluid:** Thin rim of anechoic fluid surrounding the gallbladder
- **Sonographic Murphy Sign:** Positive - maximal tenderness elicited when transducer pressure applied directly over the gallbladder
- **Common Bile Duct:** 4 mm in diameter (normal), no intraluminal stones visualized
- **Liver:** Normal echogenicity, no intrahepatic biliary dilation

**Diagnostic Criteria Met:**
The combination of gallstones, gallbladder wall thickening >3 mm, pericholecystic fluid, and positive sonographic Murphy sign meets diagnostic criteria for acute cholecystitis. The normal CBD and lack of intrahepatic ductal dilation make choledocholithiasis unlikely.

### Diagnosis
Acute calculous cholecystitis with impacted stone in gallbladder neck

### Management
1. NPO status and IV fluid resuscitation
2. IV antibiotics: Piperacillin-tazobactam (or ceftriaxone + metronidazole)
3. Pain management with IV opioids and NSAIDs
4. Surgical consultation for laparoscopic cholecystectomy
5. Early cholecystectomy (within 72 hours) preferred if patient is a good surgical candidate
6. If delayed surgery needed: Percutaneous cholecystostomy tube placement by interventional radiology
7. Pathology: Acute cholecystitis confirmed on surgical specimen

### Radiological Image

![Acute Cholecystitis Ultrasound](case_02_image.jpg)

**Image Description:** Right upper quadrant ultrasound demonstrating acute cholecystitis with gallstones (echogenic foci with posterior acoustic shadowing), gallbladder wall thickening, and pericholecystic fluid. The sonographic Murphy sign is elicited by applying pressure with the transducer over the gallbladder.

**Source:** Wikimedia Commons - "Ultrasound showing gallstones"
**URL:** https://commons.wikimedia.org/wiki/File:Gallstones_ultrasound.jpg
**License:** Creative Commons Attribution-Share Alike 3.0 Unported

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## Case 3: Acute Appendicitis with Perforation

### Patient Demographics
- **Age:** 34 years
- **Sex:** Male

### Chief Complaint
Right lower quadrant pain for 3 days, worsening

### Presenting Symptoms
The patient reports abdominal pain that began 3 days ago as vague periumbilical discomfort. Over the first 24 hours, the pain migrated to the right lower quadrant and became sharper. He initially thought it was "something he ate" and delayed seeking care. For the past 24 hours, the pain has become more diffuse and severe. He has had low-grade fevers, anorexia, and one episode of diarrhea. He reports temporary improvement in pain yesterday followed by significant worsening - concerning for perforation.

### Physical Exam Findings
- **Vital Signs:** BP 108/68 mmHg, HR 112 bpm, RR 22/min, Temp 38.9C
- **General:** Ill-appearing, lying very still
- **Abdomen:** Diffuse tenderness, most pronounced in right lower quadrant, involuntary guarding, rebound tenderness, Rovsing sign positive, psoas sign positive
- **Laboratory:** WBC 18,400/uL with 92% neutrophils, CRP 186 mg/L

### Imaging Findings and Interpretation
**CT Abdomen/Pelvis with IV Contrast:**
- **Appendix:** Dilated, thick-walled appendix measuring 14 mm in diameter
- **Perforation:** Focal defect in the appendiceal wall with adjacent extraluminal gas bubbles
- **Appendicolith:** 8 mm calcified appendicolith present within the proximal appendix
- **Abscess:** 4.2 x 3.8 cm rim-enhancing fluid collection adjacent to the appendiceal tip in the right lower quadrant
- **Periappendiceal Changes:** Extensive fat stranding and inflammatory changes in the right lower quadrant mesentery
- **Reactive Changes:** Thickening of the terminal ileum and cecal wall due to adjacent inflammation
- **Free Fluid:** Moderate amount of free fluid in the pelvis
- **No Free Air:** No large volume pneumoperitoneum

**Staging of Appendicitis:**
Based on CT findings, this represents complicated appendicitis with perforation and abscess formation (Grade 5 per the CT-based grading system).

### Diagnosis
Perforated appendicitis with periappendiceal abscess

### Management
1. IV fluid resuscitation addressing sepsis (crystalloid bolus)
2. Broad-spectrum IV antibiotics: Piperacillin-tazobactam
3. Two management options discussed:

   **Option A - Immediate Surgery:**
   - Laparoscopic appendectomy with peritoneal lavage
   - Abscess drainage at time of surgery
   - Higher risk of complications (wound infection, conversion to open)

   **Option B - Interval Appendectomy Approach (Selected):**
   - CT-guided percutaneous drainage of abscess by interventional radiology
   - IV antibiotics for 7-10 days followed by oral antibiotics
   - Interval appendectomy in 6-8 weeks after inflammation resolves
   - Colonoscopy recommended before interval surgery (age-appropriate, rule out occult malignancy)

4. Patient underwent successful percutaneous drainage with 8 French catheter
5. Clinical improvement over 5 days, abscess cavity collapsed on follow-up imaging
6. Interval laparoscopic appendectomy performed 8 weeks later without complications

### Radiological Image

![CT Appendicitis with Perforation](case_03_image.jpg)

**Image Description:** CT scan demonstrating acute appendicitis with perforation. The dilated, thick-walled appendix is visible with an adjacent rim-enhancing abscess cavity. Periappendiceal fat stranding and an appendicolith are present.

**Source:** Wikimedia Commons - "CT scan of appendicitis"
**URL:** https://commons.wikimedia.org/wiki/File:Appendicitis_CT.jpg
**License:** Creative Commons Attribution-Share Alike 3.0 Unported

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## Learning Points

1. **Transition Point Identification:** In small bowel obstruction, identifying the transition point on CT is crucial for determining the cause and planning intervention. Adhesions are the most common cause in patients with prior abdominal surgery.

2. **Sonographic Murphy Sign:** The combination of gallstones + gallbladder wall thickening (>3 mm) + pericholecystic fluid + positive sonographic Murphy sign is highly specific for acute cholecystitis and usually sufficient for diagnosis without additional imaging.

3. **Complicated vs. Uncomplicated Appendicitis:** CT can distinguish uncomplicated appendicitis (amenable to surgery or antibiotics alone in select cases) from complicated appendicitis with perforation, abscess, or phlegmon, which may benefit from initial drainage and interval appendectomy.

4. **Signs of Strangulation:** In bowel obstruction, CT findings suggesting strangulation include bowel wall thickening, decreased wall enhancement, mesenteric haziness, pneumatosis intestinalis, and portomesenteric venous gas. These findings mandate urgent surgical intervention.