Describes the clinical and radiological diagnostic signs of acute appendicitis ,complications and differential diagnosis .

1. CT
DR SAKHER-ALKHADERI
CONSULTANT RADIOLOGIST AMC
IMAGING OF ACUTE
APPENDICITIS

2. Gross anatomy
The appendix arises from the posteromedial surface of the
caecum, approximately 2-3 cm inferiorly to the ileocaecal
valve, where the taena coli converge. It is a blind
diverticulum, which is variable in length from 2-20 cm.The
appendix lies on its own mesentery, the mesoappendix .
The tip of the appendix can have a variable position within
the abdominal cavity :
-retro-caecal (65-70%)
-pelvic (25-30%)
-pre- or post-ileal (5%)

3. CT scan after oral contrast administration
in 32-year-old woman with normal
appendix. Note normal appendix with
intraluminal enteric contrast material and
gas (arrows).Appendix wall is nearly
imperceptibly thin.
34-year-old healthy volunteer with a
normal appendix.A and B, longitudinal
(A) and transverse (B) sonogram,
showing the appendix (arrowheads)
with a diameter less than the 7 mm cut-
off point, surrounded by normal
noninflamed fat.
NORMAL APPENDIX
CT SCAN ULTRASOUND

4. Appendicitis
Is inflammation of the appendix
Pathology:
Appendicitis is typically caused by obstruction of the
appendiceal lumen, with resultant build up of fluid,
secondary infection, venous congestion, ischaemia
and necrosis. Obstruction may be caused by:
-lymphoid hyperplasia (~60%)
-appendicolith (~33%)
-foreign bodies (~4%)
-Crohn disease or other rare causes, e.g. stricture,
tumour, parasite

5. Common signs of Appendicitis
•Right lower quadrant pain on palpation (the single most important sign )
•Low –grade fever (38 C { or 100.4 F} absence of fever or high fever can
occur.
peritoneal signs .
-Localized tenderness to percussion .
-Guarding .
* Other confirmatory peritoneal signs (absence of these signs does not
exclude appendicitis ) .
•Psoas sign – pain on extension of right thigh (retroperitoneal retrocecal
appendix ) .
•Obturator sign- pain on internal rotation of right thigh (pelvic appendix ) .
•Rovsing `s sign – pain in right lower quadrant with palpation of left lower
quadrant .
•Dunphy`s sign - increased pain with coughing .
•Flank tenderness in right lower quadrant (retroperitoneal retrocecal
appendix ).
Patient maintains hip flexion with knees drawn up for comfort.

6. Radiographic features
Ultrasound
Findings supportive of the diagnosis of appendicitis
include :
-Aperistaltic, noncompressible, dilated appendix ( >6 mm
outer diameter)
-Appendicolith
-Distinct appendiceal wall layers
-Echogenic prominent pericaecal fat
-Periappendiceal fluid collection
-Target appearance (axial section)

7. CT scan :
CT is highly sensitive (94-98%) and specific (up to 97%) for the
diagnosis of acute appendicitis and allows for alternative causes
of abdominal pain to also be diagnosed.
The need for contrast (IV, oral or both) is debatable and varies
from institution to institution. Findings include :
-Dilated appendix with distended lumen ( >6 mm diameter)
-Thickened and enhancing wall
-Thickening of the caecal apex (up to 80%): caecal bar
sign, arrowhead sign
-Periappendiceal inflammation, including stranding of the
adjacent fat and thickening of the lateroconal fascia or
mesoappendix.
-Extraluminal fluid
-Inflammatory phlegmon
-Abscess formation
-Appendicolith may also be identified

8. Caecal bar sign
The caecal bar sign is a secondary sign in acute
appendicitis. It refers to the appearance of inflammatory
soft tissue at the base of the appendix, separating the
appendix from the contrast-filled caecum.

9. Arrowhead sign
The arrowhead sign refers to the focal caecal thickening
centered on the appendiceal orifice, seen as a secondary sign
in acute appendicitis.The contrast material in the cecal lumen
assumes an arrowhead configuration, pointing at the
appendix.
The arrowhead sign is applicable only when enteric contrast
distends the caecum.

10. CT Technique
-The most commonly used CT technique for
studying the appendix is a scan of the entire
abdomen and pelvis after both oral and IV
administration of contrast material
-It is generally accepted that appendiceal CT
should incorporate thin-section scanning (5 mm)
through the right lower quadrant (RLQ) to
improve identification of the appendix,
CT has high accuracy for the noninvasive assessment of
patients with suspected appendicitis, with reported sensitivities
of 88–100%, specificities of 91–99%

11. CASES OF ACUTE
APPENDICITIS

12. 38-year-old man with early, acute appendicitis.UnenhancedCT scan shows
inflamed appendix measuring 10 mm in transverse diameter (arrows). Note
low-attenuation edema in submucosal layer of appendix. No appendicoliths,
free air, adjacent fluid collection, or fat stranding is seen. Surgery confirmed
early, nonperforated appendicitis.

13. 20-year-old man with acute appendicitis.Oral and IV contrast-enhancedCT
scan shows thickened, fluid-filled appendix (arrows).

14. 15 year old boy presented with symptoms and signs of acute
appendicitis. Ultrasound of the right lower quadrant
demonstrated a thickened fluid filled appendix containing an
echogenic shadowing appendicolith.
ULTRASOUND

15. An inflamed appendix has a
diameter larger than 6 mm, and is
usually surrounded by
hyperechoic inflamed fat at
sonography
NORMAL APPENDIX
ULTRASOUND

16. The appendix is distended showing mural thickening and
enhancement, with surrounding edema.

17. Enlarged appendix with wall thickening and enhancement,
appendicolith. Features of acute appendicitis.

18. Major Complications
1.Perforation
If appendicitis is allowed to progress, portions of
the appendiceal wall eventually become
ischemic or necrotic and the appendix
perforates.
CT findings—extraluminal air, extraluminal appendicolith,
abscess, phlegmon, and a defect in the enhancing appendiceal
wall—allows excellent sensitivity (95%) and specificity (95%) for
perforation in patients with known appendicitis who underwent
preoperative CT. In that study, the individual finding with
highest sensitivity was a mural enhancement defect (64%).

19. 32-year-old man with acute appendicitis.UnenhancedCT shows
appendicolith (arrowhead), periappendiceal fat stranding (black
arrows), lateral conal fascia thickening (white arrow), and
periappendiceal fluid. Perforation was confirmed on surgery

20. 2.Periappendiceal Abscess
Abscess is the most frequent complication of
perforation.The abscess remains localized if
periappendiceal fibrinous adhesions develop
before rupture. CT shows a loculated, rim-
enhancing fluid collection that may have mass
effect on adjacent bowel loops. If the abscess is
large (> 4 cm), percutaneous drainage followed
by delayed appendectomy is the preferred
treatment .

21. 47-year-old man with periappendiceal abscess. Helical CT
after IV contrast injection shows periappendiceal abscess
extending into psoas muscle (arrowheads).

22. 3.Peritonitis
4.Bowel Obstruction
5.Septic Seeding of MesentericVessels
6.Gangrenous Appendicitis

23. Differential Diagnosis
1.Mesenteric Adenitis
Mesenteric adenitis is the
most common alternative
condition identified at
negative appendectomy.
It is a benign inflammation
of the ileocolic lymph
nodes that is usually
caused by Yersinia
enterocolitica,Y.
pseudotuberculosis, or Ca
mpylobacter jejuni. CT
findings include
enlargement (> 5 mm) of
mesenteric lymph nodes,
thickening of the adjacent
cecum and ileum, and a
normal appendix

24. 2.Cecal Diverticulitis
51-year-old man with right-sided colonic diverticulitis. A,
UnenhancedCT shows extensive with fat-standing along the
cecal wall (arrowheads), and a normal appendix (arrow). B,
Sonography reveals the cause of the inflammation by depicting
an inflamed cecal diverticulum (arrow) centred in the
hyperechoic fat.

25. 3.Epiploic Appendagitis
Epiploic appendagitis is an uncommon condition caused
by inflammation, torsion, or ischemia of an epiploic
appendage.On CT, there is a small fat-attenuation mass
contiguous with the colon and having a hyperattenuating
rim. A round or linear hyperdense focus in the center of the
mass thought to represent a thrombosed central vein is
characteristic but is not always present

26. 4.Omental Infarction
Omental infarction is a rare condition in which there is
segmental infarction of some portion of the omentum.
CT features include a well-circumscribed region of
inflamed omental fat with haziness and streaklike areas
of inflammatory stranding
NB : usually larger than in epiploic appendagitis and
lacking a hyperattenuating ring on CT.

27. 5.Crohn's Disease
Crohn's disease is a chronic granulomatous inflammatory
condition that can involve any segment of the
gastrointestinal tract but most commonly involves the
terminal ileum and right colon. CT helps exclude appendicitis
and shows features characteristic of Crohn's disease.
Affected bowel usually shows prominent circumferential
wall thickening. In acute and subacute cases, IV contrast
administration shows bowel wall mural stratification (target
sign). Characteristically, skip lesions are present. Local
proliferation of mesenteric fat around the affected bowel,
prominent vessels in the hypertrophied fat, fistulas, sinus
tracts, and abscesses are frequently found . Importantly,
Crohn's disease may involve the appendix and cause a
chronic granulomatous appendicitis, which is usually
managed conservatively.

28. 28-year-old man with acute ileocecal Crohn disease.A and B, Sonography
shows transmural wall thickening of the terminal ileum (arrows) in
longitudinal (A) and transverse (B) section, with hyperechoic
inflammatory changes of the surrounding fat (arrowheads).C,Contrast-
enhanced CT confirms the wall thickening and luminal narrowing of the
terminal and pre-terminal ileum (arrowheads), with regional fat-
stranding.

29. 6.Bacterial ileocecitis
This presentation may occur in bacterial
ileocecitis, caused byYersinia, Campylobacter, or
Salmonella. Imaging studies show mural
thickening of the terminal ileum and cecum
without inflammation of the surrounding fat and
moderate mesenteric adenopathy.
US typically shows
submucosal wall
thickening (arrowheads)
of the terminal ileum
and cecum without
inflammation of the
surrounding fat.

30. Conclusion
-Helical CT with oral and IV contrast is an
accurate, effective technique for
diagnosing acute appendicitis.
-Sonography will continue to play an
important role. And probably should be
performed first in children, adolescents,
thin young adults, and women of
reproductive age with possible
gynecologic causes of pain.
-The correct diagnosis of acute appendicitis,
differentiation of appendicitis from other entities,
and identification of complications are the major
role of radiology.

31. Treatment with antibiotics alone can be a
safe and effective alternative to surgery for
children with uncomplicated acute
appendicitis, according to a new study.
UPDATES IN ACUTE APPENDICITIS

32. THE END