Medical Imaging for Trauma: When, Why & Why Not?

1. Medical Imaging for Trauma:When, Why & Why Not? Harold F. Bennett, M.D., Ph.D. Madison Radiologists, S.C. St. Mary’s Hospital University of Wisconsin Medical School Madison, WI

2. Head CT in Trauma • Image all moderate and severe head injuries • Indicated in only select mild head injury • Blunt head trauma • Pt remains awake and alert

3. Head CT for Head Injury –Canadian CT Head Rule • GCS < 15 at 2h after injury • Suspected open or depressed skull fracture • Any sign of basal skull fracture (hemotympanum, racoon eyes, cerebrospinal otorrhea or rhinorrhea, or Battle's sign) • 2 or more episodes of vomiting

4. Head CT for Head Injury -Canadian CT Head Rule • > 65 y/o • Amnesia before impact of 30min or more • Dangerous mechanism (pedestrian struck by a motor vehicle, occupant ejected from a motor vehicle, or a fall from elevation of 3' or more or 5 stairs or more) • Significantly decreased level of consciousness • Ref: Stiell (2001) Lancet 357:1394

5. Additional Indications for Head CT in Trauma • Drug or alcohol intoxication • Physical findings of trauma above clavicle • Seizure • Coagulopathy • Focal neurologic deficit

6. Minor Closed Head Injury – Imaging May Not Be Necessary • No LOC > 1min, and • Normal neurologic, fundoscopic, and mental status exam, and • No physical findings of skull fracture - hemotympanum, Battle's sign, palpable bone depression • History of seizure immediately after injury, vomiting, headache and lethargy are allowed

7. CT for Head Injury - Pediatrics • Indicated in all high risk pts < 3 m/o • Younger children are less likely to be symptomatic • Skull fracture (intracranial injury in 15-30%) • Scalp hematoma • Depressed skull fracture • Basilar skull fracture • New skull fracture <24 hours

8. CT for Head Injury - Pediatrics • Depressed mental status • Focal neurologic deficits • Bulging fontanelle • Irritability after head injury • Less predictive "high risk" criteria • Seizures • > 4 episodes of vomiting after injury • Loss of consciousness

9. CT Head or Observation (>4-6 hours) in Intermediate Risk - Pediatrics • Three to four episodes of vomiting after injury • Transient loss of consciousness • Initial irritability after injury that resolves • Skull fracture more than 24 hours old • Behavior out of norm for child

10. Skull Radiographs • Intracranial bleeds are not always associated with skull fracture and skull fracture does not always indicate intracranial lesion • CT is always recommended as initial form of evaluation if intracranial injury is suspected • Skull radiographs indicated: • If CT scanning is not readily available • In a skeletal survey in evaluation of abuse • To evaluate for foreign body

11. CT of Body – Chest, Abd &/or Pelvis – Indications Blunt trauma with: • Closed head injury • Spinal cord injury • Gross hematuria (not microscopic) • Pelvic fx, +/- suspected bleeding • Chest &/or abdominal pain • Hypotension

12. CT of Body – Chest, Abd &/or Pelvis – Indications • Pt requiring serial exams, but will be lost to physical exam for prolonged period (i.e., orthopedic procedures, general anesthesia) • Pts with dulled or altered sensorium

13. Imaging Modality in Trauma • X-rays best to assess for fractures of long bones and joints (CT – problem solving, surgical planning; MR occasionally – e.g. hip) • Chest x-ray to R/O Ptx, hemothorax, rib fx’s • CT is best for head injuries, abd or pelvis injuries, or major chest injuries • For facial bones and spine, x-rays &/or CT: • CT often as first test, and in any case if x-rays equivocal or probability of injury high • Sag and cor recons spine, cor recons face

14. CT Technique for Trauma • Head, facial bones, spine CT without contrast • Body CT • Usually IV contrast – increased sensitivity for solid organ lacerations, better evaluation of vascular injuries • Generally do not use oral contrast in interest of expediating care • Sag recons of thoracic & lumbar spine as included • Consider CT cystogram if bladder trauma (retrograde urethrogram if concern of urethral injury)

15. Acute Bleed on Head CT

16. Subdural Hematoma on Head CT

17. Subarachnoid Bleed; Skull Base Fx

18. Depressed Skull Fracture :Small Intraparenchymal Bleed

19. Facial Fractures Rt orbital blowout fx

20. Spine Fractures

21. Femoral Neck Fracture X-ray MR – T1-weighted image

22. CXR Trauma Right flail chest SQ emphysema Rt lung contusion

23. CT Chest - Trauma Left Ptx Lt lung contusion

24. CT Chest - Trauma Multiple rib fx’s

25. CT Chest - Trauma Traumatic aortic rupture Mediastinal hematoma

26. CT of Abdominal Trauma • CT most comprehensive diagnostic tool to evaluate victim of blunt abdominal trauma • Acute hemorrhage in non-contrast study is denser than liver or spleen • Appears as fluid after IV contrast • Frank hemorrhage at moment of scanning higher attenuation focus (contrast extravasation)

27. Hemoperitoneum • Small and early collections near injured organ • Sentinel clot sign - denser near site of trauma

28. Hepatic Injury • Liver injured in 15% of patients with significant blunt abdominal trauma • Mortality rate for blunt hepatic trauma 25-47%

29. Hepatic Injury - Utility of CT • Detecting injuries & defining location & extent, as well as other assoc’d injuries • Detecting hemoperitoneum • Assisting to identify patients needing laparotomy (avoiding non-therapeutic laparotomy) • Follow-up of patients managed both conservatively and surgically - document healing or detect complications (e.g., biloma or abscess)

30. Hepatic Injury - Spectrum • Intraparenchymal or subcapsular hematoma with intact capsule (no hemoperitoneum) • “Periportal tracking” • Disruption of capsule with intraparenchymal hematoma • Multiple stellate liver lac. (“bear-claw” config.) • Bursting injuries with massive parenchymal and capsular fragmentation • Transection • Avulsion of hepatic veins and injuries to hepatic arteries, bile ducts & portal veins

31. Hepatic Injury

32. Hepatic Injury

33. Hepatic Injury

34. Splenic Injury • Most frequently significantly injured organ in blunt abdominal trauma • Associated injuries: lt. lower rib fx, liver, lt. kidney, pancreas, bowel

35. Splenic Injury • Spectrum includes: • Subcapsular & intrasplenic hematoma • Splenic lacerations & fractures • Shattered spleen • Complications of trauma - e.g., infarcts & cysts, splenosis • Almost always perisplenic and intraperitoneal blood when splenic capsule interrupted

36. SPLENIC TRAUMA Subcapsular hematoma - non contrast CT Splenic laceration

37. SPLENIC TRAUMA Ruptured spleen, flattened IVC, sentinel clot, hemoperitoneum

38. SPLENIC TRAUMA Large perisplenic & intra- peritoneal bleed 2 days later Small superficial laceration at time of injury

39. SPLENIC TRAUMA - INFARCT Splenic infarct due to vascular pedicle injury (Also left renal vascular pedicle injury, pancreatic & liver lacerations)

40. Splenic Injury • CT useful in detecting, quantifying, and following splenic injury • However, CT grading scales not reliably useful in determining which patients need surgery • CT grade of splenic injury correlates with rate of healing

41. Pancreatic Injury • Uncommon - accounts for only 1-5% of blunt abdominal trauma • Mortality rate of nearly 20%, with major complications in 1/3 of survivors

42. Pancreatic Injury • Panc. injuries classified according to degree of parenchymal and ductal interruption • - Grade I - contusions or sm. hematomas (capsule intact) • - Grade II - lacs. and hematomas not extending into panc. duct • - Grade III - fractures extending through > 50% of thickness of gland w/gross disruption • - Grade IV - severe crush injuries

43. Pancreatic Injury • Grade I-II - do well with conservative management • If ductal disruption (Grade III-IV) - increased likelihood of major complication • Prompt definitive treatment lowers complication rate

44. PANCREATIC INJURY

45. PANCREATIC INJURY

46. Bowel Trauma • CT is not highly reliable • Free IP fluid is almost always present • Bowel wall thickening in >50% of bowel injuries • Dirty mesentery • Blood in mesentery • Free air not sensitive - 30-40% of patients with bowel injury • (small amount free air not absolute indication for immediate surgery)

47. Pneumoperitoneum

48. Duodenal Hematoma

49. Jejunal Perforation

50. Avulsion Mesentery Rt ColonLiver Laceration