Ultrasound is useful for evaluating appendicitis and differentiating it from other causes of right lower quadrant pain. The appendix appears as a tubular, non-compressible structure greater than 6mm in diameter with thickened walls and surrounding inflammatory changes. Other mimics include mesenteric adenitis seen as clustered lymph nodes, bacterial ileocecitis showing thickened terminal ileum and cecum, and epiploic appendagitis appearing as an inflamed fatty mass adjacent to the colon. A normal appendix helps rule out appendicitis when other gastrointestinal or gynecological conditions are present.

1. ULTRASOUND EXAMINATION OF THE APPENDIX AND GASTRO-
INTESTINAL NON-SURGICAL MIMICS APPENDICITIS.
Dr/ ABD ALLAH NAZEER. MD.

2. ULTRASOUND OF THE APPENDIX PROTOCOL
Indications
Focal RIF pain
Rebound tenderness
Pelvic pain
Elevated WCC (white cell count)
LIMITATIONS
Bowel gas and patient habitus are the biggest limiting factors to visualizing the
appendix.
Up to 60% of appendix' are retrocaecal and thus may be obscured. Not identifying
an appendix does NOT exclude appendicitis.
PREPARATION
Ideally the patient has fasted for 6 hrs. Water in the bladder is an advantage to
rule out ovarian pathology. Unfortunately the appendix is usually an urgent "fit
in" and the preparation cannot always be adhered to.
EQUIPMENT SELECTION AND TECHNIQUE
Use of a high resolution probe (7-15MHZ) is essential. Beam steering or
compounding can help to overcome anisotropy in linear structures such as
tendons. Good colour / power / Doppler capabilities. Be prepared to change
frequency output of probe (or probes) to adequately assess both superficial and
deeper structures.

3. SCANNING TECHNIQUE
Finding the appendix is highly sonographer dependent. They
must have a good skill level to undertake this examination.
begins by placing the transducer in a transverse position and
applying deep graded compression to the displace the gas and
bring the bowel closer to the probe.
Beginning at the hepatic flexure the bowel is traced down to the
cecum.
The patient should point to the location of pain .
It is a good idea to have a protocol which includes the entire
pelvis of all females with right lower quadrant pain and
scanning the renal and biliary systems of all patients with a
normal appendix.
Sometimes the external iliac artery and vein can provide a good
landmark for finding the appendix because of the location and
pulsatility, compressible, and having Doppler flow.

4. ULTRASOUND CRITERIA TO DIAGNOSE APPENDICITIS
In order to demonstrate all the possible presentations of appendicitis it is
important that the entire appendix is visualized
when the outer diameter of the appendix measures greater than 6 mm
Echogenic inflammatory periappendiceal fat change
The wall thickness can measure almost 3 mm or greater
progressed appendicitis can demonstrate a gangrenous appendix. The
lumen distends tremendously sometime upwards to 2 cm and is not
compressible. An appendicolith may be present which will cast an acoustic
shadow.
An appendicolith may be present which will cast an acoustic shadow
or a perforated appendix is demonstrated when the appendicular wall has
ruptured producing fluid or a newly formed abscess. The appearance is
hyperechoic with an echo-poor abscess surrounding the appendix. There
may be a reflective omentum around the appendix, a thickened bowel,
and enlarged lymph nodes. Asymmetrical wall thickening may indicate
perforation.
free fluid in the periappendiceal region.

5. DIFFERENTIAL DIAGNOSES VISIBLE ON ULTRASOUND:
Ovarian abnormality
•Mesenteric adenitis
•Renal calculi
COMMON PATHOLOGY:
•Appendicitis
•Mesenteric Adenitis
•Ovarian pathology
•Crohn's disease
•Diverticulitis
•Abscess

6. ULTRASOUND OF THE APPENDIX – Normal.
NORMAL APPENDIX POSITIONS
Visualization of the apex in its entirety is required
because appendicitis will may only affect the tip.

7. Refer to this study which concluded that
the location of the appendix has wide
individual variability, and the limitations
of McBurney's point as an anatomic
landmark should be recognised.
The appendix can be found from the
groin, to the umbilicus or even higher
under the liver. It is rarely midline or in
the left iliac fossa.

8. Appendicitis can be diagnosed when
the outer diameter of the appendix
measures greater than 6mm. Normal Appendix.

9. This image highlilghts the position of the cecum and the appendix (mouseover).

10. 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 non-inflamed fat.

11. Appendicitis. Longitudinal and transverse sonogram show an enlarged
appendix (arrows) surrounded by hyperechoic inflamed fat (arrowheads).

12. Appendicitis with appendicolith and color
as well as energy Doppler US images.

13. Focal appendicitis. (A) Longitudinal color Doppler image of right lower
quadrant demonstrates enlarged and hyperemic appendiceal tip (arrow)
with normal appearing proximal appendix. (B) Transverse view of right
lower quadrant image shows enlarged appendiceal tip (arrow).

14. Acute appendicitis. (A) Long axis view through the right lower quadrant demonstrates a
noncompressible, enlarged, fluid-filled blind-ending appendix (arrow). (B) Short axis scan
shows a target appearance characterized by a fluid-filled center, subadjacent layer of
hyperechoic mucosa, and outer layer of hypoechoic muscle (arrow).

15. Acute appendicitis with increased blood flow at Doppler images.

16. Inflamed appendix at sonography. Longitudinal (A) and transverse (B) cross-section show a
distended noncompressible appendix, surrounded by hyperechoic inflamed fat (arrowheads).

17. Ultrasound image obtained near in an
oblique plane shows an echovoid fluid
collection (A) representing a small abscess
adjacent to a portion of the abnormal
appendix (large arrows).
Appendicitis complicated
by an appendiceal abscess.

18. Appendiceal abscess with a collection in the right iliac
fossa with very well visualized inflamed appendix.

19. Right lower quadrant in longitudinal plane, shows an
enlarged, non-compressible appendix (small arrows),
which contains appendicoliths (large arrow). Note
that the walls of the appendix are asymmetric, thicker
posteriorly than anteriorly, and there is loss of the
expected multilayered appearance. These findings
may be associated with perforated appendicitis.
Perforated appendicitis on US. Dual gray scale
compression US image (right plot before
compression; left plot during compression) showing
an uncompressible distended appendix (cursors)
surrounded by a fluid collection (arrows).

20. Perforated appendicitis. (A) Short axis view through right lower quadrant demonstrates
enlarged appendix (arrowhead) with surrounding collection in right iliac fossa and
appendicolith (arrow) in the fluid collection consistent with perforated appendix. (B) Color
Doppler image in another patient shows complex collection (arrow) in right iliac fossa
without internal vascularity consistent with abscess secondary to appendicular perforation

21. Perforated appendix or appendiceal perforation.

22. View full size version of Retro-cecal chronic appendicitis.

23. Chronic appendicitis.

25. Gastrointestinal nonsurgical mimics of Appendicitis
Mesenteric adenitis
Mesenteric adenitis has been reported to be the
second most common cause of right lower
quadrant pain after appendicitis, accounting for 2-
14% of the discharge diagnoses in patients with a
clinical suspicion of appendicitis.
It is defined as a benign self-limiting inflammation
of right-sided mesenteric lymph nodes without an
identifiable underlying inflammatory process,
occurring more often in children than in adults.
Sonography and CT show clustered adenopathy.

26. Mesenteric adenitis. Sonogram of the right lower quadrant shows a cluster
of enlarged mesenteric lymph nodes (arrowheads). The appendix was
normal (not shown) and no other abnormalities were found.

27. Mesenteric lymphadenopathy. (A) Longitudinal view through the right lower
quadrant using graded-compression sonography shows several enlarged, oval-
shaped, mesenteric lymph node with echogenic central hilum (arrow). (B) Color
Doppler scan in another patient shows an enlarged node (arrow) with central flow

28. Bacterial ileocecitis
Because adenopathy also frequently occurs with
appendicitis, the normal appendix must be confidently
visualized on imaging studies before assigning a
diagnosis of mesenteric adenitis. Infectious enterocolitis
may cause mild symptoms resembling a common viral
gastroenteritis, but it may also clinically present with
features indistinguishable from appendicitis.
This latter presentation may occur in bacterial
ileocecitis, caused by Yersinia, Campylobacter, or
Salmonella. Imaging studies show mural thickening of
the terminal ileum and cecum without inflammation of
the surrounding fat , and moderate mesenteric
adenopathy.

29. Bacterial ileocecitis. A and B, Sonography shows moderate mural thickening
of the terminal ileum and cecum, surrounded by normal noninflamed fat.
Moderate mesenteric lymphadenopathy was also present (not shown).

30. Yersinia enterocolitis. (A) Longitudinal and (B) axial scan of the right lower quadrant show
abnormal ileum with thickened hypoechoic bowel wall (arrows) surrounding central echogenic
mucosa. The bowel lumen is collapsed. (C) Color Doppler image shows hyperemic bowel wall

31. Epiploic appendagitis
Epiploic appendages are small adipose protrusions from
the serosal surface of the colon. An epiploic appendage
may undergo torsion and secondary inflammation,
causing focal abdominal pain that simulates appendicitis
when located in the right lower quadrant.
Epiploic appendagitis is a self-limiting disease that has
been reported in approximately 1% of patients clinically
suspected of having appendicitis.
Sonography and CT depict an inflamed fatty mass
adjacent to the colon, containing a characteristic
hyperattenuating ring of thickened visceral peritoneal
lining on CT.

32. Epiploic appendagitis. A, Sonography of the right lower quadrant reveals a hyperechoic
inflamed fatty mass (arrowheads) adjacent to the colon (arrow), at the spot of maximum
tenderness. B, On unenhanced CT the fatty lesion contains a characteristic
hyperattenuating ring (arrow) corresponding to thickened visceral peritoneal lining.

33. Omental infarction
Omental infarction has a pathophysiology and clinical presentation similar to that
of epiploic appendagitis, with the infarcted fatty tissue being a right-sided
segment of the omentum. Imaging shows a cakelike inflamed fatty mass, larger
than in epiploic appendagitis and lacking a hyperattenuating ring on CT.
Omental infarction. A, Sonography of the right middle abdomen shows a large area of inflamed
intraperitoneal fat (arrowheads). B, Unenhanced CT depicts the lesion as a cake-like area of dense inflamed
omental fat (arrowheads), larger than in epiploic appendagitis and lacking a hyperattenuating ring.

34. Right-sided colonic diverticulitis
Right-sided colonic diverticulitis may clinically mimic
appendicitis or cholecystitis, though the patient's
history is generally more protracted. In contrast to
sigmoid diverticula, right-sided colonic diverticula are
usually true diverticula, that is, outpouchings of the
colonic wall containing all layers of the wall.
This may possibly explain the essentially benign self-
limiting character of right-sided diverticulitis.
Sonography and CT findings consist of inflammatory
changes in the pericolic fat with segmental thickening
of the colonic wall, at the level of an inflamed
diverticulum.

35. Right-sided colonic diverticulitis. A, Unenhanced CT 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.

36. Crohn disease
Crohn disease often causes long-standing symptoms, but up to one third of patients with ileocecal Crohn
disease present with initial symptoms so acute that they are misdiagnosed as appendicitis.
In the acute active phase of ileocecal Crohn disease, imaging shows transmural bowel wall thickening,
often predominantly of the submucosal layer, with frequent inflammatory changes of the surrounding fat.
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.

37. Gynecologic conditions
Gynecologic conditions such as pelvic inflammatory disease or
a hemorrhagic functional ovarian cyst can cause acute pelvic
pain that may simulate appendicitis.
In pelvic inflammatory disease the imaging findings vary
according to the severity of the disease, and may be normal in
early conditions.
In more advanced stages, findings may include enlargement of
the internal genital organs with indistinct contours, and free
pelvic fluid.
In absence of a drainable tubo-ovarian abscess, treatment is
medically with antibiotics.
An hemorrhagic ovarian cysts appears as a complicated cyst at
sonography and a high- attenuation adnexal mass at
unenhanced CT, and does not require any treatment.

38. Pelvic inflammatory disease. A, Endovaginal sonography shows an
inhomogeneously enlarged right ovary (arrowheads).B and C, Contrast-
enhanced CT shows enlargement of the ovaries (B, arrows) with ill-defined
contours of the ovaries and uterus, and some free pelvic fluid (C, arrow).

39. Color Doppler image through the ovary
(red arrowheads) shows absence of blood
flow demonstrating ovarian torsion. Ovarian Torsion Whirlpool Sign Ultrasound.

40. Urolithiasis
Urolithiasis may present with right lower quadrant pain when
obstruction is caused by a distal ureteral stone. Unenhanced CT is
more accurate in detecting ureteral stones than sonography.
Ureteral stone. A and B, Sonography shows right-sided hydronephrosis (A), and an
obstructing calculus (B, arrow) in the distal ureter at the level of the iliac vessels.

41. Rectus sheath hematoma
A rectus sheath hematoma may be easy to diagnose in patients presenting with a painful
palpable mass under anticoagulant therapy, however, small nonpalpable hematomas may
clinically masquerade as appendicitis and also occur in patients without anticoagulantia.
Sonography and CT show a hemorrhagic mass within the sheath of the rectus abdominis muscle.
Rectus sheath hematoma. A, Sonography depicts a small painful lesion (arrow) within the sheath of
the rectus abdominis muscle in the right lower quadrant. The lesion contains a fluid-fluid level. B,
Unenhanced CT depicts the lesion as a partly hyperdense mass (arrow) within the rectus sheath.

42. Meckel's diverticulum
The omphalomesenteric duct is an in utero structure connecting the mid-gut at the level of the ileum
to the yolk sac. It usually involutes in the first trimester. Meckel's diverticulum develops when the ileal
end of the duct remains open. Patients may present with abdominal pain due to inflammation or
intussusception with the diverticulum as the lead point (see discussion below). At sonography, the
inflamed Meckel's diverticulum appears as a hypoechoic tubular or cyst-like structure on the
antimesenteric border of the distal ileum Doppler sonography reveals hyperemia of the wall. This
appearance can mimic that of appendicitis, but an origin from small bowel rather than cecum should
suggest the diagnosis of Meckel's diverticulum.
Meckel's diverticulum. (A) Longitudinal view of right lower quadrant shows oval structure (arrow) with central
echogenic mucosa and peripheral hypoechoic muscle. (B) Longitudinal view of right lower quadrant shows
connection (arrow) of this oval hypoechoic structure with distal ileum (arrow head) Normal appendix was
seen separate from the lesion. On surgery, inflamed Meckel's diverticulum was identified.

43. Intussusception
Intussusception is one of the most common causes of acute abdominal pain in
early childhood, typically affecting children between 3 months and 2 years of age.
Approximately 90% of intussusceptions are ileocolic; the rest are ileoileocolic,
colocolic, or Ileoileal. More than 90% of intussusceptions have no pathologic lead
point and are believed to be due to inflammation of Peyer patches (lymphoid
tissue in the ileum). Meckel's diverticulum, intestinal polyps, enteric duplication
cysts, intramural hematoma, and lymphoma may also cause intussusception.
Intussusception. (A) Transverse view through the right mid-abdomen demonstrates a soft-tissue mass. Note
the hypoechoic outer rim representing the receiver loop, or intussuscipiens. The central region, or
intussusceptum, has loops of bowel and echogenic mesenteric fat and two lymph nodes (arrows) . (B)
Longitudinal view shows a reniform shape of the intussuscipiens. (C) Transverse color Doppler image shows
normal vascularity in the intestinal wall in intussusceptum and intussuscipiens.

44. Vasculitis
Henoch-Schφnlein purpura is an idiopathic systemic vasculitis characterized by purpura,
abdominal pain, arthralgia, and sometimes nephritis. The common sites of bowel
involvement are the proximal jejunum and distal ileum. Abdominal pain can precede the
onset of the skin lesions and mimic acute appendicitis. Sonography shows
circumferential bowel wall thickening, usually ranging between 5 and 8 mm in diameter
Henoch-Schönlein purpura: Long axis of the terminal ileum
show thickened echogenic small bowel wall (arrow).

45. Thank You.