Radiology in the Setting of Trauma Flashcards
Radiology “trauma series”
AP supine CXR;
X-table lateral C-spine;
AP supine pelvis
Trauma protocol CT
Head and C-spine CT without contrast, followed by a contrast CT chest/abdomen/pelvis
Why is CT so much better than x-ray for finding pneumothorax in the case of trauma?
Because the patient is lying down! This means that the air rises to the chest wall and is obscured on a plain film.
You need 3 dimensional imaging to detect that air if the patient is supine.
Main indications for trauma protocol CT
- Major trauma case
- Not possible to obtain patient history (inebriation, unconscious, etc)
You have a trauma patient with widened mediastinum on CXR. You suspect aortic disection and want to confirm, but the patient’s labs came back with a Cr of 3.6. What do you do?
Rather than CT, do a transesophageal ultrasound.
MRI is a theoretical anternative, but usually in trauma cases the acuity does not permit time for an MRI scan.
CT findings of traumatic aortic dissection
- Widened mediastinum with fluid opacities
- Intimal flap visualized within the aorta
- Focal bulge
- Pseudoaneurysm
- Mediastinal hematoma (usually at the level of the ligamentum arteriosum)
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Traumatic aortic injury vs aortic dissection
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Traumatic aortic injury: Multiple presentations –
- Aortic laceration is a tear in the intima and aortic transection is a tear of all three layers of aorta and can result in aortic rupture.
- Aortic pseudoaneurysm is a contained localized rupture. The pseudoaneurysm is contained by an intact adventia.
- Intramural hematoma represents localized bleeding in the wall of the aorta.
- Localized dissection can occur at the site of aortic injury but this is uncommon.
- Aortic dissection: Aortic dissection results from a tear in the intima, resulting in two channels of flowing blood. An aortic dissection can rupture and allow blood to extravasate into the pleural space or mediastinum, although most are diagnosed unruptured.
Upper limit of normal for defining ascending aortic aneurysm
< 4 cm is normal for ascending aorta
> 4 cm is an abscending aortic aneurysm
Deep sulcus sign
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It is very hard to identify pneumothorax from a supine radiograph.
This is one of the ways that you can.
On a supine radiograph, the deep sulcus sign may be the only suggestion of a pneumothorax because air collects anteriorly and basally, within the non-dependent portions of the pleural space, as opposed to the apex when the patient is upright. Thus, the costophrenic angle is abnormally deepened and often radiolucent.
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Studies in the setting of suspected rib fracture
AP CXR is first line in most cases.
However, if you suspect splenic rupture, don’t waste your time: Get an abdominal CT.
Also, if abuse or malignancy is suspected, you may consider getting a dedicated rib film in addition to (not instead of) an AP CXR.
What is going on in this CXR?
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Pneumomediastinum
Look very closely at the left mediastinal-pleural border, and on the lateral thoracic inlet in the neck.
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Subpleural blebs
Blebs of trapped air underneath the pleura, inside of the mediastinum.
When someone suffers trauma, often a fall, they may rupture and result in spontaneous pneumomediastinum or pneumothorax. This usually resolves spontaneously as the air is gradually resorbed.
Same as discussed w/ Marfan syndrome and related syndromes – it’s just whether or not they happen to be mediastinal.
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Patient arrives following blunt abdominal trauma. FAST scan is negative for abdominal fluid. What is the next step?
Depends on the clinical context.
If the suspicion for bleed is low and the patient does not have any abdominal symptoms (pain, tenderenss) or volume loss (delayed capillary refill, decreased peripheral pulses), you are done looking for a bleed.
If any of the above are present, you should do an abdominal CT, which is much more sensitive for bleeding.
Where does a FAST scan look?
- Perihepatic
- Perisplenic
- Pelvic
- Pericardiac
Rule of thumb for solid abdominal organ truama management
- If the patient is hemodynamically stable and there is no evidence if active bleed (even if a hematoma is present), then nonoperative management is preferred.
- If unstable or actively bleeding from the spleen or liver, embolize or take for open repair
- If the patient is stable but over age 70, consider taking to OR anyway (may rapidly decompensate)
- Any diaphragmatic, bowel, or mesenteric injury is an indication for surgical management.