Imaging abdomen trauma introduction part 1 Dr Ahmed Esawy include different cases for oral radiodiagnosis examination all over the world CT /MRI Plain X ray images blunt abdominal trauma penetrating abdominal trauma fast abdominal ultrasound

2. An Article By
Dr. Ahmed Esawy
MBBS M.Sc MD

4. Trauma to the abdomen
accounts for approximately 10% of the
traumatic deaths. Prompt recognition and
management of bleeding from intra-
abdominal organs is essential to
minimize morbidity and mortality from
trauma itself as well as minimizing the
need of surgical interference with
probable its complications.

5. Classification of Abdominal Trauma:
A. Blunt Abdominal Trauma (BAT):
- Compression or concussive forces (direct blows)
- Deceleration forces
• B. Penetrating Abdominal Trauma (PAT):
- High-velocity injuries (gunshots)
- Low-velocity penetrating injury (stab wounds)

7. Imaging Techniques:
1- Initial imaging:-
- FAST
- Plain X-ray
2- CT
3-conventional Angiography
4- MRI
5- Isotope Scan

8. The primary role of CT is to assess
the severity of abdominal injuries
in order to help the trauma
surgeon to decide if emergent
surgery is necessary.
Therefore, if surgery is mandatory
due to the severity of the
abdominal trauma, then CT is
generally avoided.

9. IN INTERPRETING CT FOR
PATIENTS WITH
ABDOMINAL TRAUMA, WE
HAVE TO SCREEN FOR

10. 1) Pneumothorax and
pneumoperitoneum using
lung windows for lower thorax
and upper abdominal sections
and soft tissue windows for
lower abdominal and pelvic
sections;

11. (2) left paracolic gutter
and spleen for blood
or laceration

12. (3) right paracolic
gutter and liver, for
blood or laceration

13. (4) upper abdominal
survey evaluating
duodenum and pancreas

14. (5) Retroperitoneal survey of
kidneys, adrenals, IVC and
aorta for evidence of
bleeding, laceration,
hematoma, urinoma

15. (6) GI tract and
mesentery for
extravasation or
hematoma

16. (7) muscle survey including
psoas,
iliopsoas,
rectus abdominus
and buttocks for hematoma

17. (8) bone survey
including
ribs,transverse
processes, sacrum, and
SI joints
and hips
for fracture

18. (9) lowest section
search for groin
hematoma

19. BAT
FAST
Positive FAST Negative FAST
Stable Patient Unstable Patient Stable Patient Unstable Patient
CT Laparotomy Repeat FAST after 6 hrs Identify other cause
APPROACH FOR ABDOMINAL
TRAUMA

20. Abdominal Trauma Protocol
• Blunt injury -deceleration, crush, weapon
(e.g. bat)
– venous phase ~70 secs
– Delayed scan if injury present; ~3-5 mins
• Penetrating injury: knives, gun
– Same as blunt
– Additional scan after rectal contrast material

21. • The findings to look for in
abdominal trauma are the
following:
–Hemoperitoneum
–Pneumoperitoneum
–Contrast blush consistent with active
extravasation
–Subcapsular hematomas
–Laceration
–Contusions
–Devascularization of organs or parts
of organs

23. Active bleeding
The CT appearance of
intraperitoneal blood
depends on the age
and physical state of
the clot.

24. IMMEDIATELY AFTER
HEMORRHAGE,
INTRAPERITONEAL BLOOD
HAS THE SAME
ATTENUATION AS
CIRCULATING BLOOD OF
20-30 HU

25. Active bleeding
However, attenuation values less than 20 HU are
a frequent finding in the acute setting. The
proposed reason for this is that blood, being
a strong peritoneal irritant, causes a local
inflammatory response with transudation of
fluid across the peritoneum. Transudate fluid
mixes with and dilutes the blood before
coagulation begins, decreasing the attenuation.

26. Active bleeding
Within hours, a clot forms and attenuation
increases as hemoglobin concentrates, and
values in the range of 50-75 HU are seen.
Densely clotted blood may have attenuation
values upwards of 100 HU.
Clot lysis begins within 48-72 hours, and
attenuation decreases to fluid values.
After a few weeks, most hematomas have
attenuation values approaching those of water,
namely, 0-20 HU.

27. Active bleeding
In reality, hemoperitoneum can have a complex
appearance as a result of recurrent
hemorrhage and irregular resorption. Blood
may exist in many different stages at the time
of imaging if hemorrhage has been intermittent.
Fresh blood
confined to a localized space or that has been
relatively undisturbed may separate,with
plasma layered on top of precipitated red blood
cells causing the hematocrit effect.

28. Quantification of hemoperitoneum
Huang and associates scoring systems
• Total Score ranging from 0 to 8
• One point was assigned to each anatomic
site in which free fluid was detected during
the FAST scan
• Fluid of more than 2 mm in depth in the
hepatorenal or the splenorenal space was
given 2 points instead of 1
• Floating loops of bowel were given 1 point
• Scores > 3 required exploratory laparotomy

29. Approximately
• FAST can detect between 100-250ml
0.5 cm in Morison's Pouch = 500ml
1 cm in Morison's Pouch = 1000ml
CT can detect volumes of free fluid as
low as 100ml

30. Volume
• Detection of fluid in each paracolic
gutter indicates that at least 200 ml of
blood must be present in each gutter.
• CT visualization of blood in the
abdomen and pelvis corresponds with
the amounts of more than 500 ml.

31. Hemoperitoneum
Hyperdense intraperitoneal fluid collection
0–20HU Preexisting ascites
Bile
Urine
Digestive fluid
Diluted (acute blood) or old blood
30–45HU Free Unclotted intraperitoneal blood
45–70HU Clotted blood/sentinel clot sign hematoma
>100 HU Extravasation of contrast medium
(vascular or urinary)

32. SENTINEL CLOT SIGN
• Clotted blood adjacent to
the site of injury is of higher
attenuation value than
unclotted blood which
flows away .
• When the source of
intraperitoneal bleed not
evident, the location of
highest attenuating blood
clot is a clue to the most
likely source

33. Ascites – Radiographic findings
• Obliteration of inferior edge of liver
• Widening of distance b/n flank stripe &asding colon
• AF b/n liver & lateral abd wall may result in
visualization of a lucent band –Hellmer’s sign
• Dog ear sign or ‘Mickey mouse ears’ sign(100-
150ml)- fluid density lateral to rectal gas shadows.
• Separation and floating of bowel loops
• Bulging properitoneal flank stripe
• Poor definition of major abd. organs and psoas
• Overall abdominal haziness

34. Retroperitoneal Hemorrhage
• Retroperitoneal hemorrhage may
arise from injuries to major vascular
structures, hollow viscera, solid
organs, or musculoskeletal
structures or a combination

35. Small zone I (central)
retroperitoneal hematoma

36. Large zone I (central)
retroperitoneal hematoma with
active extravasation

37. Large zone II (lateral)
retroperitoneal hematoma

38. The CT appearance of
intraperitoneal blood
depends on the age
and physical state of
the clot.
Active bleeding

39. IMMEDIATELY AFTER
HEMORRHAGE,
INTRAPERITONEAL BLOOD
HAS THE SAME
ATTENUATION AS
CIRCULATING BLOOD OF
20-30 HU

40. However, attenuation values less than 20 HU
are a frequent finding in the acute setting. The
proposed reason for this is that blood, being
a strong peritoneal irritant, causes a local
inflammatory response with transudation of
fluid across the peritoneum. Transudate fluid
mixes with and dilutes the blood before
coagulation begins, decreasing the
attenuation.
Active bleeding

41. Within hours, a clot forms and attenuation
increases as hemoglobin concentrates, and
values in the range of 50-75 HU are seen.
Densely clotted blood may have attenuation
values upwards of 100 HU.
Clot lysis begins within 48-72 hours, and
attenuation decreases to fluid values.
After a few weeks, most hematomas have
attenuation values approaching those of water,
namely, 0-20 HU.
Active bleeding

42. In reality, hemoperitoneum can have a complex
appearance as a result of recurrent
hemorrhage and irregular resorption. Blood
may exist in many different stages at the time
of imaging if hemorrhage has been
intermittent. Fresh blood
confined to a localized space or that has been
relatively undisturbed may separate,with
plasma layered on top of precipitated red blood
cells causing the hematocrit effect.
Active bleeding

43. CT findings of shock
• Collapse of inferior vena cava
• Small aorta
• Persistent nephrogram without excretion
• Hypodense spleen, without enhancement and
normal vascular pedicle
• Increased enhancement of the small bowel wall
• Increased enhancement of the adrenal glands
• Sometimes findings of right cardiac insufficiency
with reflux into the hepatic veins

44. PNEUMOPERITONEUM
• FREE AIR SENSITIVITY OF IMAGING
STUDIES
– COMPUTED TOMOGRAPHY- 99%
– AP UPRIGHT CHEST RADIOGRAPH - 76%
– LEFT DECUBITUS ABDOMEN RADIOGRAPH 80 -90%
– SUPINE ABDOMEN RADIOGRAPH - 56%

45. Signs of a pneumoperitoneum on the supine
radiograph
Right upper quadrant gas
Perihepatic
Subhepatic
Morrison’s pouch
Fissure for the ligamentum teres
Rigler’s (double wall) sign
Ligament visualization
Falciform (ligamentum teres)
Umbilical (inverted V sign) medial and lateral
Urachus
Triangular air
The cupola sign
Football or air dome
Scrotal air (in children)

46. SOLID
ORGAN
INJURY

47. Solid organ injury includes:
- liver, spleen and kidneys.
- Injury of the urinary bladder.
- Bowel and mesenteric injury.
- Pancreatic injury.
-Injury to the abdominal aorta.
- Diaphragmatic rupture.
- Pelvic trauma.

48. On CT, it is usually seen in a lenticular configuration.
Sub-capsular hematomas cause direct compression
and deformity of the shape of the underlying solid
organs. On non-enhanced CT scans, the solid organs
appear hypo-attenuating compared with a sub-capsular
hematoma. On enhanced CT scans, a sub-capsular
hematoma appears as a low-attenuating lenticular
collection between the capsule and the enhancing
parenchyma of the injured organ. Unless bleeding
recurs, attenuation of the sub-capsular hematoma
decreases with time. Sub-capsular hematomas resolve
within 6-8 weeks
Subcapsular hematoma

49. On enhanced CT, laceration appears
as a non-enhancing linear or
branching structure, usually at
periphery. Acute lacerations have a
sharp or jagged margin, but with
time, lacerations may enlarge, and
the margins may develop rolled
edges. Multiple parallel lacerations
occur as result of compressive
forces (bear claw lacerations).
Lacerations:

50. contusions are perceived as ill-defined
or sometimes sharply marginated
areas of reduced enhancement and
excretion

51. On enhanced CT, acute hematomas appear as
irregular high-attenuation areas,which
represent clotted blood, surrounded by low-
attenuating unclotted blood. Over time, the
attenuation of the hematoma is reduced, and
the hematoma eventually forms a well-defined
serous fluid collection that may expand slightly.
A focal intraparenchymal hyper attenuating
area with attenuation of 80-350 HU may
represent an
active hemorrhage or pseudo-aneurysm. .
Intra-parenchymal hematomas