1. Dr/ ABD ALLAH NAZEER. MD.
Radiological imaging of diverticular
disease and diverticulitis.

2. Definitions:
Diverticulum–sac-like protrusion of the colonic
wall that consists of mucosa, submucosa, serosa
Diverticulosis–the presence of diverticula, often
an incidental finding
Diverticulitis–inflammation resulting from a
perforation of a diverticulum
Diverticular Hemorrhage–Diverticular bleeding
usually not associated with diverticulitis

4. Epidemiology
Age: Affects <5% before 40yo-30% at 60yo-65% at 80yo.
20% of those present with sxs.
Risk factors:
“disease of Western Civilization”
low fiber constipation.
obesity, lack of physical activity.
NSAIDs.
Smoking.
Pathophysiology
95% of diverticuli occur in the sigmoid
In Asians, 70% present as R-sided pain
Laplace’s law: (P=T/r), sigmoid has the smallest diameter and largest pressures.
Segmentation exaggerated-increase in intraluminal P

6. Colonic diverticular disease most commonly affects the
rectosigmoid colon. The pathophysiology of diverticular disease is likely to
be related to a complex relationship between age, dietary factors, colon
structure and motility. Diverticular disease is traditionally accepted as a
condition of Western civilization. The condition is rarely encountered in
populations inhabiting rural regions with Asia and Africa. Raised intra-
colonic pressure occurs as an adaptative mechanism to a low-fibre diet,
which is associated with an increased transit time. This is associated with
increased desiccation and viscosity of the fecal content, promoting the
development of diverticula.
Diverticulitis is the most common clinical complication of colonic
diverticular disease. Diverticulitis results from obstruction at the neck of a
diverticulum leading to localized inflammation. Smoking is associated with
an increased risk of complications in diverticular disease. Opioid
analgesics, non-steroidal anti-inflammatory drugs and corticosteroids are
all positively associated with an increased risk of perforated colonic
diverticular disease. Calcium channel blockers, which reduce colonic
contractility and tone, protect against perforation in colonic diverticular
disease.

7. Radiological imaging:
Plain abdominal X-ray
Only to exclude significant abnormalities in intestinal passage and free intra-
abdominal gas.
Not suitable for detecting diverticulitis.
Sonography
Generally available and cheap method of investigation
Highly dependent on the ease of imaging and the experience of the Practitioner
Complicated disease is difficult to recognize (pelvic abscesses, fistulas, etc.)
Mono-contrast barium enema, Inadequately sensitive for detecting peri diverticular
inflammation, abscesses, and fistulas.
Only recommended when CT not available for organizational reasons.
Computed tomography
Method of choice, also for recognition of the complicated disease CT guided drainage
is possible.
Magnetic resonance imaging
Used in trials, routine use still premature
Colonoscopy
Mainly indicated for the reliable exclusion of tumors – during periods free of
inflammation.
Angiography.

8. X-ray investigation /colonography
Either double-contrast or mono-contrast techniques may be used for conventional X-ray
investigations of the colon. The reliability of both procedures depends directly on how
well the patient is prepared. The double-contrast technique with aqueous barium
sulphate solution is principally restricted to the post acute phase (after at least 7 days).
This technique is contraindicated for acute diagnosis, as there is a risk of perforation –
indeed a covered perforation may already have developed – and this can lead to loss of
barium, with the risk of barium peritonitis. In addition, contrast medium containing
barium may remain in the intestine for long periods and may complicate an operation
should this become necessary. The imaging of the diverticulum is also adequate, although
the inflamed diverticulum is only observed as "spicule-like" mucous membrane avulsions,
due to the obstruction in the diverticulum neck. The segmental extension of the
inflammation can be well documented. Free perforations can be easily recognized by the
detection of extra-intestinal contrast medium. On the other hand, it is difficult to detect a
covered perforation. This can often only be indirectly inferred from the extra-mural
indentations of the intestinal wall from small pericolic micro-abscesses. A colon contrast
enema often gives inadequate images of peridiverticular inflammatory reactions and of
changes in complicated diverticulitis. The colon contrast medium investigation only
detected a peridiverticular abscess in 29% of cases demonstrated by computed
tomography. Moreover, the overall extent of the inflammatory reaction is markedly
underestimated by both procedures. According to the literature, the sensitivity of the two
procedures lies between 71% and 94% (13), with specificities between 61% (13) and 72%

9. Sonography
Sonography – including duplex sonography and harmonic imaging – is a widely
available imaging procedure. In principle, the patient should fast before the
investigation, but no other preparation is necessary. After a preliminary investigation
of the whole abdomen, a specific image is taken of the intestinal structures with a high
resolving linear transducer (7.5 to 10 MHz). Sonographic studies have shown that
localized thickening of the intestinal wall can be imaged with high sensitivity. In
particular, the so-called dome sign is thought to be highly specific for diverticulitis.
This is a hypoechogenic hemispherical lesion, eccentrically positioned near the
intestinal wall. The center of this lesion is hyperechogenic, corresponding to the
inflamed diverticulum. According to the literature, the sensitivity of sonography for
diverticulitis lies between 79% and 98% and its specificity, between 80% and 98%.
Direct imaging of the inflamed diverticulum is moderately sensitive (77%), but highly
specific (99%) for diverticulitis. Sonography's sensitivity for the uncomplicated form is
as high as 96%. However, imaging the inflamed diverticulum is often not possible,
particularly in complicated diverticulitis. In addition, there is often an increase in the
echogenicity of the pericolic fat tissue, corresponding to inflammatory edematous
changes (sensitivity: 15% to 50%). Additional sonographic signs of complicated colonic
diverticulitis include pathological cockades with a very narrow lumen (inflammatory
stenosis) and the direct detection of peridiverticular abscesses. These may be
hypoechogenic and also exhibit an intermediate reflection pattern, with or without
gas (sensitivity about 40%).

10. Computed tomography
Computed tomography has become the diagnostic gold standard. It is performed as spiral-
CT on single or multi detector row CT (MDCT) scanners. The patient is then given both an
oral and a rectal dose of contrast medium (CM). The investigation is performed after
intravenous administration of contrast medium in a portal vein CM phase. Intravenously
administered spasmolytics can also greatly facilitate intestinal imaging. In modern MDCT,
primary layer collimations of 0.6 to 1.5 mm are primarily selected. In addition, multiplanar
reformatting can be used to improve the presentation and documentation of the findings.
Data acquisition is performed from the level of the sub-phrenic space to the symphysis
pubis, with the aim of directly detecting any alternative diagnosis which might
imitate the symptoms of diverticulitis. Typical changes found in diverticulitis are
symmetrical thickening of the inflamed intestinal wall (normal thickness about 3 to 5 mm),
with segment size of > 10 cm (sensitivity 95%, specificity 31%), and diffuse edematous
infiltration of the pericolic fat tissue (sensitivity 95%, specificity 35%). found fluid
accumulation around the root of the mesentery and increased vascular injection in the
mesosigmoid, with the high predictive values of 89% and 100% for diverticulitis.
Free perforations can be imaged from the intraluminal gas or with contrast medium.
Abscesses are diagnosed by computed tomography in 100% of cases. Even with computed
tomography, detection of fistulae is difficult. Colovesicular fistulae or fistulae between the
colon and uterus can be indirectly inferred from the gas in the area of the urinary bladder
and/or the uterus, if there has been no prior use of the instruments which might have
interfered (e.g. a urinary bladder catheter). Computed tomography can also detect rare
complications, such as septic thrombosis of the mesenteric vein

11. Magnetic resonance imaging
Because of the lack of radiation exposure and the high soft tissue contrast, MRI
has become established as an alternative to computed tomography for intestinal
imaging, particularly in younger patients and for some specific indications. 1.5
Tesla MR tomographs are usually used. Imaging mostly employs either body coils
or highly resolving surface coils.
There is not yet any reliably established and standardized procedure for the
diagnosis of diverticulitis. There has been wider experience with imaging
processes linked to chronic inflammatory bowel disease, particularly Crohn's
disease. For these measurements, intestinal contrast is achieved using 2.5%
mannitol solution administered orally. The detection of diverticulitis was based
not only on intestinal wall thickening, but also locally increased uptake of contrast
medium and pericolic inflammatory reactions. Magnetic resonance imaging gives
good images of the pericolic inflammatory reactions.
Colonoscopy
Endoscopy is of most use in diverticulitis in the intervals free of inflammation. This
method can reliably exclude colonic cancer and other inflammatory diseases of
the colon.

12. Angiography
Diverticular bleeding in the colon is the most frequent cause of lower
gastrointestinal bleeding. About 3% to 15% of patients with diverticulosis
suffer bleeding in the course of their lives this is caused by rupture of the
vasa recta. This event occurs independently of acute or chronic
inflammatory reactions and tends to cease spontaneously. For reasons
which remain unclear, this is much more frequent in diverticulae of the
ascending colon than in sigmoid diverticulae. The primary procedure for
diagnosis and treatment is currently endoscopy. If bleeding cannot be
controlled, primary surgical treatment is indicated. There are also rare
cases in which the bleeding point can be localized with digital subtraction
angiography, possibly combined with CT-angiography using an
angiographic catheter in the mesenteric artery. In some cases
superselective catheterization and embolization of the bleeding vessel is
possible. The success rates for primary hemostasis vary between 83% and
94%. 27% to 34% of patients suffer renewed bleeding, despite successful
primary embolization. It should always be born in mind that intestinal
wall ischemia is a possible complication.

14. Meckel's diverticulitis. Supine abdominal
radiograph shows cholelithiasis (arrow) and
dilated loops of small bowel (arrowhead)
Upright abdominal radiograph shows
dilated loops of small bowel, with
multiple air fluid levels (arrows

16. Barium enemas of manifestations of diverticulitis, (A) Acute diverticulitis with
edema (arrow) of the bowel wall. (B) Intramural sinus tract (arrow) in acute
diverticulitis. (C) Confined perforation or abscess (arrow) in acute diverticulitis.

17. Radiograph showing extensive diverticulosis.

18. Radiological evidence of acute diverticulitis
(arrows) using water-soluble contrast medium.

21. Sigmoid diverticulitis at sonography. A hypoechoic thickened
diverticulum is surrounded by hyperechoic inflamed fat (arrows).

23. 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.

24. Sigmoid diverticulitis: sigmoid colon with multiple diverticula,
significant mural thickening (arrow) and pericolic fat stranding (circles).

28. Mild diverticulitis of the sigmoid colon. CT demonstrates evidence of multiple
diverticula in association with mild bowel wall thickening and pericolic fat stranding.

29. Moderate diverticulitis of the distal descending colon. CT shows moderate bowel
wall thickening in association with marked stranding and phlegmon formation.

30. Transverse CT of the lower abdomen post-oral and intravenous
contrast media demonstrates marked stranding (open arrow)
surrounding a thickened diverticulum (closed arrow) within the right
colon. The features are pathognomonic of acute diverticulitis.

31. Computed tomographic scan revealing marked eccentric thickening of the
wall of the ascending colon and pericolic inflammatory fat and fascia
(white arrowheads). Fecal material is seen at the center of the
inflammatory complex indicating an inflamed diverticulum (black arrows).

32. MRI images for sigmoid diverticulitis.

33. Magnetic resonance image (MRI) of right-sided diverticulitis.

34. Computed tomographic (CT) findings in acute diverticulitis (arrow)
with accumulation of pus (abscess) around the bowel (x).

35. Sigmoid diverticulitis with abscess formation: sigmoid colon displaying
diverticulosis mural thickening, and pericolic fat stranding (arrow). Adjacent low
attenuation, septated collection (circle) representing abscess formation.

37. (a) Transverse CT in a
patient with sigmoid
diverticulitis
demonstrates a large
pelvic abscess with an
air fluid level situated
in the pouch of
Douglas. (b) An 8 F
pigtail drainage
catheter has now
been successfully
placed trans-gluteally
into the collection.
The collection
resolved fully on
subsequent imaging.

38. Transverse CT post-intravenous contrast medium in a patient with acute
diverticulitis shows a 5 cm abscess cavity in the left iliac fossa (straight
arrow). There is a pocket of air within the abscess cavity (curved arrow)
indicating communication to bowel. Diverticulitis is present within the
sigmoid colon as evidenced by thickening of the bowel wall and stranding.

39. Severe diverticulitis
of the recto-sigmoid
colon with localized
perforation and
abscess formation.
(a) Transverse CT
through the lower
pelvis demonstrates
marked thickening of
the proximal
contrast-filled rectum
(arrow). There is
extensive stranding
of the mesocolon.
(b) At a higher level,
there is a localized
perforation with
abscess formation
(arrow).

40. Radiological visualization of an incomplete
fistula (arrow) in a patient with diverticulitis.

42. Transverse CT through the pelvis in a patient with diverticulitis
demonstrates a localized perforation in the left side of the pelvis. A tract of
air can be seen connecting the sigmoid colon to the air collection (arrow).

43. Perforated sigmoid diverticulitis: sigmoid colon displaying diverticulosis, mural
thickening and pericolic inflammatory fat stranding (arrow) with adjacent
collection of intra-abdominal free air and adjacent inflammatory fat stranding
(circle), again representative of active diverticulitis with perforation.

49. Patient with sigmoid diverticulitis and a colovesical fistula. There is free
air within the anterior aspect of the bladder (arrow). The patient had no
recent bladder instrumentation. There is also associated thickening of the
sigmoid colon, which is adherent to the left side of the bladder.

50. MRI images with
Colovesical fistula
is a devastating
complication,
usually secondary
to diverticulitis.

51. CT scans of manifestations of diverticulitis, (A) Contained abscess (arrow) in severe
sigmoid diverticulitis. (B) Large air-containing abscess (arrow) in subacute diverticulitis.
(C) Large diverticular abscess (arrow) with penetration into retroperitoneal structures
and extending through abdominal wall into subcutaneous tissue.

52. a) Transverse CT through
the pelvis demonstrates
acute diverticulitis of the
proximal sigmoid colon
with bowel wall thickening,
diverticula and some
localized free air (arrow). (b)
Magnified view at a higher
level shows air within the
branches of the superior
mesenteric vein (arrow). (c)
There is portal venous air
within the liver. Despite
these findings, the patient
was not acutely
unwell and made a full
recovery after surgery.

53. Transverse CT through the upper abdomen in a patient with perforated
diverticulitis viewed on lung windows. There is extensive free intra-
peritoneal air with visualization of the falciform ligament (arrow). There is
also extensive retroperitoneal air and subcutaneous air on the left side.

54. Transverse CT in a patient with palpable subcutaneous emphysema and a known
past history of diverticulitis. There is extensive air extending from adjacent to the
descending colon through the abdominal wall into the subcutaneous tissues.

57. Selective Angiography Diverticular Bleeding.

58. Technetium-99m-tagged red blood cell scan
showing extravasation of tagged red blood
cells into the colon lumen in the sigmoid
and descending colon, with radionuclide
collection in the descending colon (arrow).
Colonoscopic image of a blood-
filled colon with clots and
diverticula (arrows).

59. Conclusions
CT is a highly specific and sensitive imaging
method in the evaluation of acute
diverticulitis. It is the most accurate imaging
technique available for the assessment of the
inflammatory process. CT-guided
percutaneous drainage of diverticular
abscesses plays a crucial role in improving
patient outcome.

60. Thank You.