Ch.17 - Recognizing the Imaging Findings of Trauma Flashcards
Most trauma-related injuries are due to:
Blunt trauma - Motor vehicle accidents contributing the majority.
Role of CT in trauma:
Profound impact in traumatized patients by distinguished those patients who can be managed conservatively from those who need surgical or other interventions.
Rib fractures:
May herald more serious internal injuries such as lacerations of the liver or spleen or pneumothoraces.
Rib fractures - Most occur:
Ribs 4-9.
Pulmonary contusions:
MC manifestation of blunt chest trauma and represent hemorrhage into the lung, usually at the point of impact.
–> Classically clear in a few days.
Pulmonary lacerations:
- Tears in the lung parenchyma that may contain fluid or air.
- Their presence may be hidden by a surrounding contusion.
- Typically take longer than a contusion to clear.
Aortic injuries:
- Usually occur at the isthmus.
- Require rapid recognition for optimum survival.
- On contrast-enhanced CT may take the form of intimal flaps/contour/abnormalities/or hematomas.
MC affected solid organs in BLUNT abdominal trauma in order of decreasing frequency:
- Spleen.
- Liver.
- Kidney.
- Urinary bladder.
Liver injury:
- Commonly injured in BOTH blunt and penetrating trauma.
- Its injuries account for the majority of the deaths from abdominal trauma.
- May demonstrate lacerations/hematomas/wedge-shaped defects/pseudoaneurysms/acute hemorrhage.
Renal trauma:
- Almost all have hematuria.
- May show contusions, lacerations, hematomas, or vascular pedicle injuries on CT.
- May also demonstrate extraluminal contrast from an injury to the renal pelvis or ureter.
Shock bowel:
- Consequence of profound hypotension.
2. Shows diffuse small bowel wall thickening with enhancement of dilated and fluid-filled loops on CT.
Bladder ruptures:
- Either extra-peritoneal (more common) or intra-peritoneal.
- Extra-peritoneal –> Extraluminal contrast surrounding the bladder.
- Intra-peritoneal –> Showing contrast flowing freely in the peritoneal cavity.
Urethral injuries:
Almost exclusively in males
- Frequently associated with pelvic fractures.
- Usually involve the posterior urethra –> Extra-luminal contrast may be seen in the perineum or extraperitoneally in the pelvis.
Focused Abdominal Sonogram for Trauma (FAST):
- Portable US utilized on unstable trauma patients solely to identify free peritoneal fluid.
- Used primarily in place of the diagnostic peritoneal lavage.
- False negatives occur with abdominal injuries in which there is NO hemoperitoneum.
Trauma is generally divided into:
- Blunt.
2. Penetrating.
Blunt trauma usually the result of?
Motor vehicle accidents and is the more common of the two categories.
Penetrating trauma is usually the result of …?
Accidental or criminal stabbings and gunshot wounds.
Chest injuries are responsible for … out of … trauma-related deaths.
1 out of 4.
The overwhelming majority of chest traumas are the result of …?
Motor vehicle accidents.
Fractures of ribs 1-3 is …?
Relatively UNCOMMON –> Indicates a sufficient amount of force to produce other internal injuries.
Fractures of ribs 4-9 are …?
COMMON and IMPORTANT if they are displaced (pneumothorax) or if there are 2 fractures in each of three or more contiguous ribs –> flail chest.
Flail chest is almost always accompanied by …?
Pulmonary contusion –> Significant mortality.
Fractures of ribs 10-12 may indicate …?
The presence of underlying trauma to the liver (right side) or the spleen (left side), especially if they are DISPLACED.
In cases of MINOR trauma, is not unusual …?
For rib fractures to be undetectable on the initial examination but to become visible in several weeks after callus begins to form.
Pulmonary contusions are the most frequent complications of …?
Blunt chest trauma –> They represent hemorrhage into the lung –> Usually at the point of impact.
Recognizing a pulmonary contusion - What is of paramount importance?
The history of trauma.
Contusions present as airspace disease that is indistinguishable from other airspace diseases like pneumonia or aspiration.
Recognizing a pulmonary contusion - Location?
Contusions tend to be peripherally placed and frequently occur at the point of max impact.
Recognizing a pulmonary contusion - Air bronchograms?
Are usually NOT present because blood fills the bronchi as well as the airspaces.
Classically, contusions appear within …?
6 hours after the trauma.
Contusions disappear within …?
72hr, sometimes sooner –> Blood in the airspaces tends to be reabsorbed quickly.
Pulmonary hematomas result from a …?
Laceration of the lung parenchyma and, as such, may accompany more severe blunt trauma or penetrating chest trauma.
A pulmonary laceration is also called a …?
Traumatic pneumatocele or hematoma.
Recognizing a pulmonary laceration - Their appearance will depend on …?
Whether they contain blood and, if so, how much blood fills the laceration.
Recognizing a pulmonary laceration - If they are completely filled with blood …?
They will appear as a solid, ovoid mass.
Unlike pulmonary contusions that clear rapidly, pulmonary lacerations …?
May take weeks or months to completely clear.
Trauma to the aorta is most frequently the result of …?
Deceleration injuries in motor vehicles accidents.
Which patients with trauma to the aorta survive to be imaged?
Only those with incomplete tears in which the adventitial lining prevents exsanguination (producing a pseudoaneurysm).
What is the MC site of aortic injury?
The aortic isthmus.
Seat-belt injuries may involve …?
The abdominal aorta.
What is the only chance of blunt aortic injuries?
Only emergency SURGERY will prevent approx. 50% of patients with blunt aortic injuries from dying within the first 24hr if left untreated.
A NORMAL CXR has a … for aortic injury.
HIGH NEGATIVE PREDICTIVE VALUE.
AN ABNORMAL CXR has a … for aortic injury.
A relatively LOW PPV (78%).
“Widening of the mediastinum” …?
Is usually a poor means of establishing the diagnosis because it is difficult to assess on a supine, portable CXR and it is commonly OVERINTERPRETED.
Other signs that may be present in aortic injury CXR?
- Loss of normal shadow of the aortic knob.
- A left apical pleural cap of fluid or blood.
- A left pleural effusion.
- Deviation of the trachea or esophagus to the RIGHT.