CT Protocol
CT was performed on an 128 channel (Somatom Perspective) multidetecto CT scanner.
Acquisition of thin sections covering the abdomen and pelvis from the dome of the diaphragms through the pubic simphysis were aquired in a single breath hold.
Oral contrast was administered if the patients condition allowed.
Normal Anatomy
The appendix is a tubular like structure (veriform) whose mean length is about 6 to 8cm in adults and 2 to 15cm in children.
Its mean diameter is 7mm. Fig. 2
The wall measures about 1-2mm.
It arises from the posteromedial surface of the caecum,
approximately 3cm inferiorly to the ileocaecal valve,
having its own mesentery.
The relationship of the base of the appendix to the ceacum is always constant,
the free end is mobile which accounts for its variable locations.
Positions:
- retrocaecal (65%-70%) Fig. 3
- pelvic (25%-30%) Fig. 9
- pre or post ileal (5%)
Clinical Findings
Around 50% of patients present with the classic signs and symptoms of acute appendicitis.
Atypical presentations lead to a delay in diagnoses.
Variations in the position of the appendix,
age and degree of inflamation make the clinical presentation of appendicitis notoriously inconsistent.
Appendicitis is one of the more common causes of acute abdominal pain,
its a clinical emergency.
Typical signs and symtoms:
- Abdominal pain: Typically begins as periumbilical or epigastric pain that migrates to the right lower quadrant.
- Rebound pain
- Nausea
- Anorexia
- Vomiting
- Diarrehea or constipation
- Elevated temperature
- Leukocitosis
Alvarados Scoring System
Characteristic |
Points |
Migration of pain to right lower quadrant |
1 |
Anorexia |
1 |
Nausea and vomiting |
1 |
Tenderness in righgt lower quadrant |
2 |
Rebound pain |
1 |
Elevated temperature |
1 |
Leukocitosis |
2 |
Shift of white blood cell count to the left |
1 |
TOTAL |
10 |
- Score < 5 Appendicitis unlikely
- Score 5 or 6 Appendicitis possible
- Score 7 or 8 Appendicitis likely
- Score 9 or 10 Appendicitis highley likely
This table has been prospectively validated in several populations of children and adults.
CT Findings of The Normal Appendix
- Tubular stucture,
the lumen can be collapsed or partially filled with air or fluid.
Fig. 3
- Mean diameter 7mm
- No fat stranding adyacent
CT Findings of Accute Appendicitis
Complications: Indicators of perforated appendicitis
- peiappendiceal fluid collection
- pericecal phlegmon
- extraluminal appendicolith
- air near appendix Fig. 13
Factors that complicate diagnoses of appendicitis:
- scanty intraabdominal fat
- unusual location of caecum and appendix
- small bowell dilatation
Differntial Diagnoses
Patients with acute right lower quadrant pain may have other conditions that mimic appendicitis.
These include:
Inflammatoty and infectious conditions
Malignancies
Other conditions
- intussusception Fig. 22
- epiploic appendagitis
- mesenteric adenitis
- omental infarction
- pelvic inflammatory disease
- ovarian haemorragic cyst or torsion Fig. 23
- ischemia
- ectopic pregnancy