CT of Trauma

1CT OF TRAUMA

Myron A. Pozniak, MDUniversity of WisconsinDepartment of RadiologyDepartment of Radiology

2Life has changed

General facts regarding trauma

Leading cause of death in the first four Leading cause of death in the first four decades of life.

150,000 deaths/year in U.S.

2,000,000 nonfatal injuries in the U.S./year.

3General facts regarding trauma

Injuries due to violence make up 14% of Injuries due to violence make up 14% of injuries

Unintentional fall - 52%

Evaluation of the trauma patient

Obtain the maximum information in the Obtain the maximum information in the shortest possible time.

Critically unstable patients belong in the operating room.

4Routine ER x-rays

AP chest AP chest Lateral cervical

spine AP pelvis Cross table lateral

T and L spine

Indication for emergency trauma imaging

Unexplained drop in hematocrit

Confusing physical exam

Hemodynamically stable patient

5Choices for emergency trauma imaging

Diagnostic peritoneal lavage (DPL) Diagnostic peritoneal lavage (DPL)

Ultrasound (US)

Computed Tomography (CT)

Diagnostic peritoneal lavage (DPL)

Advantages Disadvantages Quick Inexpensive

Invasive No idea which organ is injured No information about retroperitoneumretroperitoneum Does not allow non-operative management

6FAST UltrasoundAdvantages Disadvantages

Variable sensitivity and specificity (operator dependent)

Absence of free fluid with retroperitoneal injury or non-capsule disrupting injury

Performed at bedside Noninvasive Relatively inexpensive No IV contrast

p p g j y Poor at identifying acute

parenchymal organ injury Very low sensitivity for bowel

and renal injuries

Computed Tomography(CT) Advantages Disadvantages Non-invasive Organ specific Highly accurate Allows non-operative

management

Time consuming Relatively expensive Intravenous iodinated contrast risk Poor for bowel and pancreasPoor for bowel and pancreas injuries

7CT vs. DPL vs. Ultrasound - Which one?

Patient selection

Trauma managers preference

Quality / availability / experience of the various services

Ultrasound has replaced DPL for the detectionUltrasound has replaced DPL for the detection of free intraperitoneal fluid

CT provides much more information and allows for non operative managementallows for non-operative management

8Trauma CT technique

Proximity to the emergency room Proximity to the emergency room Sub-second rotation time Multi-detector system High heat capacity tube Power injector Remote patient monitoring

Trauma CT technique (cont.)

Patient Preparation Sedation

Alcohol/drugs/head injury Oral contrast

Two cups if toleratedJ i i Just prior to scanning

Clamp the Foley catheter Minimize artifacts

9Minimize artifacts

EKG lead artifact

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Arms at side

Metal Bar Artifact

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Not all metal is necessarily Artifact

Carpenters nail gun


Intravenous ContrastIntravenous Contrast Low osmolar contrast 150 cc or 100 cc with a 50 cc saline chaser 4 cc/sec Bolus tracking (cardiac contusion)

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Contrast enhancement key to determination of organ integrity

Non-contrast After IV contrast

Trauma CT technique (cont.)Scan Sequence Chest - diaphragm to apexp g p

1.25 mm collimation High speed (15 table feed) .625 mm reconstruction

Abdomen/pelvis 2.5 mm collimation High speed table feed 2.5 mm reconstruction Extremity run off - if indicated

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Delayed sequence (7 minutes) Kidneys through bladder 5 mm collimation

Consider filling the bladder retrograde (CT cystogram)( y g )

Targeted reformatting of bony anatomy Obviates the need for a re-scan

Several critical observations:

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Look at the box

Surface findings indicateSurface findings indicate point of impact

Fractures Localized hematoma Seat belt injury Seat belt injury

Look at the box

Surface findings indicateSurface findings indicate point of impact

Fractures Localized hematoma Seat belt injury Seat belt injury

15

Always check the bone windows -especially the vertebral column

Cine evaluation Cine evaluation Lateral scout view

Free intraperitoneal fluid

Very useful finding but not after DPLVery useful finding but not after DPL Blood Urine Bile Intestinal contents

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The subtle nondisplaced rib fracture must not be ignored

Active bleeding

appears as an enlarging puddle of contrastpp g g p

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If in doubt get that delayed scan

7 minutes later

The size of the potential space is a key determinant of survival

Liters Gallons

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So what do you do with this patient

Go to the OR Observe

Aortic injury

16% of all deaths from MVA 16% of all deaths from MVA

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Timing of death with aortic injury

Within 1 hour in 94% Within 1 hour in 94% Within 24 hours in 99%

Ann Thorac Surg 1994;57(3):726-730

Aortic injury

Variable confidence level for exclusion of tear Variable confidence level for exclusion of tear

A small collection of mediastinal blood even if periaortic rarely correlates with a significant

i i jaortic injury

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How many of you would dictate:

Cant rule out aortic injury.?

Increasing the frequency of post-traumatic angiography because of mediastinal blood on CT negates the advantage of this tool.

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54 y/o female unrestrained passenger

Focal Dissection Raised Intimal Flap

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A Media I

The ability of CTA to identify aortic injury exceeds the treatment threshold.

Traumatic Aortic Injury

We are in a period of transition We are in a period of transition - the stakes are high - definitive supporting literature is just

appearing

Subjective assessment is very good at predicting aortic injury but not the CXR

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A normal CXR does NOT exclude aortic injury


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Endovascular repair of aortic injury Endovascular repair of aortic injury

Mortality of emergent aortic surgery is very high - 54%

Indications for stenting evolving

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Small Intimal Tear

Natural history of arterial injuries diagnosed with arteriography.Hoffer EK, Sclafani SJ, et al.Hoffer EK, Sclafani SJ, et al.

The natural history variable and unpredictable. Nonocclusive "minimal" injuries rarely cause

ischemic or hemorrhagic complications. Cl f ll i i l if i Close follow-up is essential if a non-operative approach is chosen.

J Vasc Interv Radiol. 1997 Jan-Feb;8(1 Pt 1):43-53

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Acute Aortic Pseudoaneurysm

Delayed diagnosis of the intimal tear

Chronic pseudoaneurysm rate 5% Chronic pseudoaneurysm rate - 5%

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The isolated mediastinal hematoma is not as serious a finding as previously thought.

Cannot R/O aortic injury Cannot R/O aortic injury If the CTA is normal leave it alone We lack a large study to confirm this.

Angio the not-so-gold standard

Positives are slam dunks Positives are slam-dunks Small intimal tears are

easily overlooked

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Post-traumatic Dissection

Not all aortic injuries are at the arch

18 y/o in a stolen car tried to outrun the police

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Post traumatic pseudoaneurysm

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Look carefully for aberrant great vessels Look carefully for aberrant great vessels -may affect the ability to cross clamp the aorta at surgery

If theres a lower extremity fracture

Include the leg in the CTA run Include the leg in the CTA run.

31

Splenic injuries Most commonly injured

abdominal organ (46%) 30-60% have associated

abdominal injuries Isolated injuries have better

prognosis

SPLEEN INJURY SCALE

I. Hematoma 3 cm

IV. Laceration with >25% devascularizationV. Completed shattered or devascularized spleen

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With rapid scan acquisition during the l h f h t lti livascular phase of enhancement a multislice

scanner can go past a slow active bleeder before it has time to accumulate a significant amount of extraluminal contrast.

Maintain a low threshold for delayed scan.

27 y/o Hispanic male3 f ll 3 story fall

Comatose Stable hematocrit CT abdomen/pelvis at the same time as the C abdo e /pe v s at t e sa e t e as t e

head CT

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24 y/o male MVA Splenic laceration

Scanned 4 days later, after a drop in hematocrit

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62 y/o female MVA Initial CT showed a splenic

lacerationlaceration Follow-up CT scan 8 days later

Inhomogeneous enhancement of the spleen Artifact of rapid dynamic enhancement

Arterial phase Venous phase

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No role for non- contrast CT in trauma

Lacerations can be missed Lacerations can be missed

Non-contrast After IV contrast

Liver injuries

2nd most commonly injured organ in blunt 2nd most commonly injured organ in blunt trauma

Most common in penetrating trauma Right lobe injuries are most common

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LIVER INJURY SCALEI. Hematoma

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Concept of the Stress riser

UW Quarterback fell on the football

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Active bleeding appears as a puddle of contrast opacified blood

Active bleed hepatic segment 4B

Active bleeding appears as a puddle of contrast opacified blood

If its more than a puddle Go to the OR

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CT detected acute trauma bleeds

Only 4 out of 5 require OR Only 4 out of 5 require OR the higher the attenuation the closer the

focus of the bleed Yao & Jeffrey

Renal Trauma

Mechanisms of InjuryMechanisms of Injury Direct blow Laceration by rib or foreign body Tear from rapid deceleration

Stress riser

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Clinical signs of renal trauma

Gross hematuria Gross hematuria 25% have significant injury

Microhematuria 1-2% have significant injury (usually severe

pedicle injury with vascular avulsion)

Renal injury

95% are managed non operatively 95% are managed non-operatively Focal contusion Superficial laceration Segmental infarction Perinephric hematoma Subcapsular hematoma

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Renal injuries requiring surgery

Parenchymal fragmentation (maybe) Parenchymal fragmentation (maybe) Ureteral avulsion Major hemorrhage (maybe)

Grading of Renal Injury

American Association for the Surgery of American Association for the Surgery of Trauma (AAST)

Grades 1-5 Not consistently used

Often used by surgeons for research purposes Hard for us to remember!

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Grade I

80% of all injuries 80% of all injuries Contusions, nonexpanding subcapsular

hematomas, hematuria with negative imaging

C i i d fi d hi f Contusion is defined as geographic area of decreased enhancement (sharp or diffuse margins)

Grade 1: Contusion

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Grade I: Subcapsular Hematoma

The hilum is spared The hilum is spared

Grade I: Subcapsular Hematoma

Appearance varies Appearance varies with maturity Most are post-

lithotripsy

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Grade 2

Nonexpanding perinephric retroperitoneal Nonexpanding, perinephric, retroperitoneal hematomas

Superficial cortical lacerations

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Grade 3

Renal lacerations >1cm in depth Renal lacerations >1cm in depth These do not involve the collecting system

Grade 4

Lacerations extending to collecting system Lacerations extending to collecting system Extravasation of contrast on delayed images

Contained main renal artery/vein injury Segmental infarction without laceration

Wedge-shaped areas of non-enhancementWedge shaped areas of non enhancement Caused by dissection, thrombosis or laceration of

segmental arteries

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Grade 4: Collecting System Extravasation

Initial spiral sequence must be followed by a delayed scan

The problem with IV contrast and trauma

S ti i l l i t i ll k dl l t d Serum creatinine level is typically markedly elevated with urine extravasation.

High creatinine should not preclude the use of IV contrast in a trauma patient

Dont bother with Cr levels in severe traumaDon t bother with Cr levels in severe trauma It takes too long You wont give contrast to the pt. that needs it most

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Grade 4: Vascular injury (contained)

Traumatic renal artery dissection/intimal tear Traumatic renal artery dissection/intimal tear Can be treated with stent

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Grade 4: Vascular injury (contained)

Grade 4: Segmental Infarcts

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Grade 5

Shattered kidney Shattered kidney Devascularized kidney

Non-enhancement may be only sign of injury no hematoma or urinoma

UPJ avulsion Little or no hematuria

Grade 5: Shattered Kidney

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Grade 5: Devascularization


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Grade 5: UPJ avulsion

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Grade 5: UPJ avulsion

Bottom Line

Kidney is salvaged 85 90% Kidney is salvaged 85-90% Conservative management Grades 1-3 Even most Grades 4-5 are conservatively

managed Indications for surgery: large devitalized Indications for surgery: large devitalized

areas, major arterial injury, UPJ avulsion, unstable patient with active extravasation.

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Remember the stress riser

Is it a tear of the collecting system?

Persistent Active Extravasation

This finding may require intervention no This finding may require intervention no matter what the AAST grade

Either surgery, or catheter embolization

54

but Active Extravasation may slow as the compartment fills.

The Horseshoe Kidney especially prone to injury

55

Bladder Trauma

10% f ll GU 10% of all GU trauma involves the bladder

Intraperitoneal Seat belt injury Seat belt injury

Extraperitoneal Pelvic fracture

Grading: 5 Types

Type I: Mucosal tear most common no imaging findingsType I: Mucosal tear, most common, no imaging findingsType II: Intraperitoneal, 10-20% of major injuries, caused

by blow to distended organ, dome ruptureType III: Interstitial rupture, CT cystography, contrast in

bladder wall. Blunt or penetrating injuryT IV E t it l 80 90% f j i j iType IV: Extraperitoneal, 80-90% of major injuries,

contrast in prevesicular space, tracking along fascia to thigh, scrotum

Type V: Combined intra- and extraperitoneal, ~5%

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Intraperitoneal Extraperitoneal

Intraperitoneal Extraperitoneal

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Which Test?

CT cystography is just as accurate as CT cystography is just as accurate as retrograde cystography if bladder is distended with 300-400ml of contrast

CT cystography gives the advantage of evaluating the remainder of the abdomenevaluating the remainder of the abdomen and pelvis

Overall cost and time savings

CT cystogram

6% contrast via Foley 6% contrast via Foley catheter (50 cc of 60% contrast in 500 cc of saline)

Warm to body temperaturetemperature

5 mm collimation

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Is it urine or is it blood?

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Urethral Injury

Typically at urogenital Typically at urogenital diaphragm

Best imaging retrograde urethrogram (pre attempted Foley(pre-attempted Foley cath insertion)

Urethral Injury

Typically at urogenital Typically at urogenital diaphragm

Best imaging retrograde urethrogram (pre attempted Foley(pre-attempted Foley cath insertion)

61

Urethral Injury

Adrenal bleed

Most commonly seen after: Most commonly seen after: Direct iatrogenic insult

Liver transplant Childbirth

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Adrenal bleed

smallsmall

medium

large

Super-sized with an active bleeder

early late

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Intestinal injury

Accuracy of CT is quite Accuracy of CT is quite variable

Most frequently affects duodenum and terminal ileum

Oral contrast or not?

Takes too long Takes too long Post-traumatic

ileus

But when it extravasates

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Duodenal Contusion

Duodenal Bleed It appears we may no longer need oral contrast

Intramural Intraluminal

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Traumatic duodenal perforation

Retroperitoneal Retroperitoneal air and blood

Anterior pararenal space

CT is good at detecting perforation Free air Free fluid Free fluid

CT is poor at detecting: Contusion Mesenteric hemorrhageg Ischemic Serosal tear

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Body habitus makes a big difference

Mesenteric hematoma


Active bleeder

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Bowel wall hematoma

Bowel wall hematoma

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GI Perforation

Inter loop fluid / triangular configuration = bowel perforationBut not quite as certain in ovulating females

Few perforation cases actually have free air

Focal jejunal perforation at surgery.

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Shock BowelProfound HypotensionReperfusion after injuryReperfusion after injuryHyperdense bowel

Pancreas injury

Changes of post-traumatic pancreatitis are time Changes of post-traumatic pancreatitis are time dependent

Initial scan - limited findings

Delayed scan Phlegmon Pseudocyst Etc.

70

Pancreatic fracture/contusionOften with steering wheel injury

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2 k l2 weeks later

Traumatic rupture of the diaphragm

Incidence: 4 6% of MVA cases Incidence: 4 6% of MVA cases

Mortality rate of missed tear approaches 30%.

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The diaphragm is the weakest link of the The diaphragm is the weakest link of the abdominal cavity enclosure, especially at the transition between the central tendon and the muscular portion.


Radiographic identification of the tear hinges on the presence of herniation.

Delayed if patient on Positive Pressure VentilationVentilation

Up to 70% of diaphragmatic tears are initially missed.

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Liver Herniation

CT diagnosis limited CT diagnosis limited in the absence of herniation

Omental Herniation

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Gastric Herniation

Miscellaneous findings in trauma

Flat inferior vena cavaFlat inferior vena cava

Hypovolemia

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Malpositioned chest tube

Quiz cases

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MVAhematuria

Renal Artery Laceration with Brisk Active Bleed

MVAdropping hematocrit

Active hemorrhage from Inferior Epigastric Artery

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MVAunresponsivewide mediastinum on CXR

Aortic laceration

MVAunresponsive

Patient demise at start of scan

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Conclusions

Hemodynamically stable patient

CT angiographic technique for aorta

Dynamic enhancement technique for h l i jparenchymal injury

Delayed scans for urinary tract injury

Conclusions

Elevated serum creatinine level should not Elevated serum creatinine level should not preclude the use of intravenous contrast in a trauma patient

l d d id if i Delayed scan mandatory to identify urine leak

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Conclusions cont.

If the delayed scan is negative but the If the delayed scan is negative but the clinical concern for bladder injury is high, consider a CT cystogram Antegrade filling may not raise bladder

pressure sufficientlyp y The need for a post void sequence is

questionable

With rapid scan acquisition during the Conclusions cont.

vascular phase of enhancement a multislice scanner can go past an active bleeder before it has time accumulate a significant amount of extraluminal contrast.

Maintain a low threshold for delayed scan

80

Heres a crazy thought

I NG t b tiIs NG tube suction

really helping the patient

with the big bleed?

Heres a crazy thought

Is the NG tube to suction reallyIs the NG tube to suction really helping the patient with the big bleed?

Its all about the potential space

81

Thank you

84

Lumbar artery pseudoaneurysm

85

internal iliac bleed

86

subtle mural aortic hematoma

87

Can chest CT be used to exclude aortic injury?

1009 patients 1009 patients 10 true positives, no false negatives 100% sensitivity 100% negative predictive value

Dyer DS et al.Radiology 1999;213(1):195-202

Post traumatic dissection

88

Not all metal is necessarily Artifact

Gunshot wound

Natural history of arterial injuries diagnosed with arteriography.Hoffer EK, Sclafani SJ, et al.Hoffer EK, Sclafani SJ, et al.

105 arterial injuries were identified average duration of observation was 23.5 days 42 healed spontaneously p y no significant M&M due to delay

J Vasc Interv Radiol. 1997 Jan-Feb;8(1 Pt 1):43-53

89

Delayed scan (bolus drip technique) has little role in solid organ injury

Redistribution of contrast hides lacerationsRedistribution of contrast hides lacerations

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CT of Trauma