Soft Tissue Soft Tissue Radiographic Findings in Radiographic Findings in

Blunt Chest TraumaBlunt Chest Trauma

Jonathan Yarris MSIVJonathan Yarris MSIV

November 2004November 2004

TraumaTrauma

• Trauma is the leading cause of death in Trauma is the leading cause of death in patients < 40 yearspatients < 40 years

• 44thth leading COD overall leading COD overall

• 80% of trauma is due to blunt mechanisms80% of trauma is due to blunt mechanisms• Includes: falls, MVC’s, industrial injuriesIncludes: falls, MVC’s, industrial injuries

Blunt Chest Trauma (BCT)Blunt Chest Trauma (BCT)

• Seen in about ½ of blunt trauma casesSeen in about ½ of blunt trauma cases• ~20% of trauma deaths attributable to BCT~20% of trauma deaths attributable to BCT• Etiology: typically deceleration injuryEtiology: typically deceleration injury• Radiographic evaluation should begin Radiographic evaluation should begin

immediately after initial trauma team immediately after initial trauma team assessmentassessment

• Initial study usually supine chestInitial study usually supine chest• CT for aortic, pulmonary, airway, skeletal, diaphragm CT for aortic, pulmonary, airway, skeletal, diaphragm

injuryinjury• Limited role for MRILimited role for MRI

Approach to Trauma Approach to Trauma RadiographsRadiographs

• Initial exclusion of life threatening injuries Initial exclusion of life threatening injuries

• Followed by search for less critical injuriesFollowed by search for less critical injuries

• Life threatening Injuries:Life threatening Injuries:• Acute aortic injury, other vascular traumaAcute aortic injury, other vascular trauma• cardiac contusion, rupture, tamponade cardiac contusion, rupture, tamponade • Tension pneumo, flail chest, tracheobronchial Tension pneumo, flail chest, tracheobronchial

injuryinjury• Spinal fracture and dislocationsSpinal fracture and dislocations

PneumothoraxPneumothorax

• ~20% of patients with penetrating trauma~20% of patients with penetrating trauma

• 30-40% of patients with BCT30-40% of patients with BCT

• Usually small but potential for problems Usually small but potential for problems with mechanical ventilation or GAwith mechanical ventilation or GA

• Pleural air will rise to non-dependent Pleural air will rise to non-dependent portions of the lung:portions of the lung:

Upright Upright Apex Supine Apex Supine anterior/caudal anterior/caudal

PneumothoraxPneumothorax

Supine Signs (CXR)Supine Signs (CXR)1.1. Deep sulcus sign = deep lucent Deep sulcus sign = deep lucent

costophrenic sulcuscostophrenic sulcus2.2. Increased lucency at effected lung baseIncreased lucency at effected lung base3.3. Double diaphragm sign – ventral and Double diaphragm sign – ventral and

dorsal portions of PTX adjacent to dorsal portions of PTX adjacent to anterior and posterior aspects of hemi-anterior and posterior aspects of hemi-diaphragmdiaphragm

CT: PTX seen in 10-50% of pts with neg. CT: PTX seen in 10-50% of pts with neg. CXR in head or BCTCXR in head or BCT

Deep Sulcus SignDeep Sulcus Sign

Tension PneumothoraxTension Pneumothorax

• High intrathoracic pressure causes High intrathoracic pressure causes decreased cardiac filling decreased cardiac filling

• Compression of ipsilateral lungCompression of ipsilateral lung

• Displaced mediastinum away from PTXDisplaced mediastinum away from PTX

• Kinking of the great vessels can lead to Kinking of the great vessels can lead to hemodynamic collapsehemodynamic collapse

Tension PTXTension PTX

Pulmonary Parenchymal Pulmonary Parenchymal InjuryInjury

• ContusionContusion

• LacerationLaceration

• HematomaHematoma

ContusionContusion• Def: Edema and alveolar/interstitial Def: Edema and alveolar/interstitial

hemorrhagehemorrhage• 30-70% of BCT’s, Mortality = 25%30-70% of BCT’s, Mortality = 25%• Assoc. with multiple rib fractures and Assoc. with multiple rib fractures and

flail chestflail chest• Occurs in Occurs in children and young adults w/o children and young adults w/o

associated rib fractureassociated rib fracture• Usually develops within 6 hrs and Usually develops within 6 hrs and

resolves in 2-3 daysresolves in 2-3 days

ContusionContusion

• Findings: CT and CXRFindings: CT and CXR• Non-segmental consolidation usually in lung Non-segmental consolidation usually in lung

periphery, adjacent to area of traumaperiphery, adjacent to area of trauma

• CT is far more sensitive than CXRCT is far more sensitive than CXR

• DDX of opacification = aspiration, DDX of opacification = aspiration, atelectasis, cardio- and non-cardiogenic atelectasis, cardio- and non-cardiogenic edemaedema

Pulmonary ContusionPulmonary Contusion

ContusionContusion

LacerationLaceration

• Def: disruption of alveolar spaces with Def: disruption of alveolar spaces with formation of a cavity filled with blood/airformation of a cavity filled with blood/air

• Etiology: penetrating trauma or shear forcesEtiology: penetrating trauma or shear forces• Often obscured by assoc. hematomaOften obscured by assoc. hematoma• Findings on CT: Findings on CT:

• ““Swiss Cheese” - Air collections within area of Swiss Cheese” - Air collections within area of consolidationconsolidation

• Ovoid air spaces surrounded by 2-3 mm of Ovoid air spaces surrounded by 2-3 mm of pseudomembranepseudomembrane

Laceration with PneumatoceleLaceration with Pneumatocele

HematomaHematoma

• Due to complete filling of laceration Due to complete filling of laceration cavity with bloodcavity with blood

• Finding: well circumscribed, round Finding: well circumscribed, round nodulenodule• May see air fluid levels as resolvesMay see air fluid levels as resolves

• Traumatic PneumatoceleTraumatic Pneumatocele = air-filled = air-filled cystic space following acute laceration cystic space following acute laceration or resolution of pulmonary hematomaor resolution of pulmonary hematoma

Pulmonary hematomaPulmonary hematoma

PneumatocelePneumatocele

Pulmonary Contusion with Pulmonary Contusion with pneumatocelepneumatocele

Blunt Cardiac Injury (BCI)Blunt Cardiac Injury (BCI)

• Occurs in 8-71% of BCTOccurs in 8-71% of BCT

• 80-90% of BCI is immediately fatal80-90% of BCI is immediately fatal

• 70-80% of patients with BCI have external 70-80% of patients with BCI have external signs of chest traumasigns of chest trauma

• Sternal fracture does not predict BCISternal fracture does not predict BCI

• Usual site is right ventricleUsual site is right ventricle

• Can lead to hemopericardiumCan lead to hemopericardium

HemopericardiumHemopericardium

Hemopericardium Hemopericardium with tamponadewith tamponade

Great Vessel InjuryGreat Vessel Injury

• Deceleration vascular injuryDeceleration vascular injury• 81% Aortic rupture alone81% Aortic rupture alone• 16% aorta and branches16% aorta and branches

• Left subclavian 38%, Bracheocephalic 21%, R subclavian Left subclavian 38%, Bracheocephalic 21%, R subclavian 16.5%, L common carotid 16.5%, Vertebral 8% 16.5%, L common carotid 16.5%, Vertebral 8%

• 3% only branches3% only branches

• Concern for branch injury if perivascular Concern for branch injury if perivascular superior mediastinal or low cervical hematoma, superior mediastinal or low cervical hematoma, especially in the presence of especially in the presence of upper rib fracturesupper rib fractures

Thoracic Aorta InjuryThoracic Aorta Injury

• 90% lethal before receiving emergency care90% lethal before receiving emergency care• Usually a transverse laceration of part or all of Usually a transverse laceration of part or all of

aortic circumferenceaortic circumference• 60% have adventia intact = pseudoaneurysm60% have adventia intact = pseudoaneurysm• Injury to root or ascending aorta is nearly 100% Injury to root or ascending aorta is nearly 100%

fatalfatal• ~90% occur at aortic isthmus just distal to left ~90% occur at aortic isthmus just distal to left

subclaviansubclavian• 4-10% of cases have concomitant great vessel 4-10% of cases have concomitant great vessel

injuryinjury

Thoracic Aorta InjuryThoracic Aorta Injury

• Initial study frontal chest radiographInitial study frontal chest radiograph• Normal study has 98% neg. predictive valueNormal study has 98% neg. predictive value• Abnormal study has high false positive rate Abnormal study has high false positive rate

(PPV<20%)(PPV<20%)

• Findings:Findings:• CXR: mediastinal hematomaCXR: mediastinal hematoma• CT: Aortic tear, abnl contour, pseudoaneurysm, CT: Aortic tear, abnl contour, pseudoaneurysm,

intimal flap, active extravasation, abrupt taper intimal flap, active extravasation, abrupt taper (pseudocoartation), hematoma(pseudocoartation), hematoma

• A negative CT has near 100% negative A negative CT has near 100% negative predictive value for aortic injurypredictive value for aortic injury

Thoracic Aorta InjuryThoracic Aorta Injury

Intimal Flap with Intimal Flap with double lumendouble lumen

Thoracic Aorta InjuryThoracic Aorta Injury

Airway InjuryAirway Injury• Tracheobronchial tears are uncommonTracheobronchial tears are uncommon

• < 0.35-1.5% of BCT< 0.35-1.5% of BCT• bronchial > tracheal bronchial > tracheal • 75% at R mainstem usually within 2.5 cm of carina 75% at R mainstem usually within 2.5 cm of carina

• Leads to persistent PTXLeads to persistent PTX• Specific Symptom: persistent PTX after chest Specific Symptom: persistent PTX after chest

tube placementtube placement• Finding: “Fallen Lung Sign”, Finding: “Fallen Lung Sign”,

pneumomediastinum,pneumomediastinum, pneumopericardium, sub pneumopericardium, sub cut. Emphysemacut. Emphysema

• ET Tube balloon inflation >2.8cm implies tracheal ET Tube balloon inflation >2.8cm implies tracheal rupturerupture

PneumomediastinumPneumomediastinum

• Etiology: alveolar, tracheobronchial or Etiology: alveolar, tracheobronchial or esophageal ruptureesophageal rupture

• Most common cause: alveolar rupture due to Most common cause: alveolar rupture due to sudden increased intra-alveolar pressure sudden increased intra-alveolar pressure (Macklin Effect) with air tracking centrally(Macklin Effect) with air tracking centrally

• Findings: Findings: • Air outlining mediastinal soft tissues and parietal Air outlining mediastinal soft tissues and parietal

pleura.pleura.• Continuous diaphragm signContinuous diaphragm sign

PneumomediastinumPneumomediastinum

PneumomediastinumPneumomediastinum

PneumomediastinumPneumomediastinum

Pneumopericardium with Pneumopericardium with tamponadetamponade

Pneumopericardium with Pneumopericardium with tamponade resolvedtamponade resolved

Esophageal InjuryEsophageal Injury

• <10% of esophageal rupture is caused by <10% of esophageal rupture is caused by traumatrauma

• < 1% of BCT’s< 1% of BCT’s• Findings:Findings:

• PneumomediastinumPneumomediastinum• Left PTXLeft PTX• Left pleural effusionLeft pleural effusion• Sub cut emphysemaSub cut emphysema• Left lower lobe atelectasisLeft lower lobe atelectasis

OtherOther

• Skeletal injuries:Skeletal injuries:• Spine, sternal, and rib (common in BCT)Spine, sternal, and rib (common in BCT)

• Diaphragm injuries:Diaphragm injuries:• Penetrating > BCT (1-8%)Penetrating > BCT (1-8%)• Left > rightLeft > right• Postero-lateral portionPostero-lateral portion• Herniated hollow viscusHerniated hollow viscus

Follow-up QuizFollow-up Quiz

• Test yourself and view chest trauma cases Test yourself and view chest trauma cases at the University of Wisconsin Radiology at the University of Wisconsin Radiology website:website:

• http://www.radiology.http://www.radiology.wiscwisc..eduedu/Med_Students/chest/chest-trauma./Med_Students/chest/chest-trauma.htmhtm

BibliographyBibliographyZinck, Primack. Radiographic and CT findings in Blunt Chest Trauma. Journal of Thoracic Imaging. 15, 87-96, 2000Zinck, Primack. Radiographic and CT findings in Blunt Chest Trauma. Journal of Thoracic Imaging. 15, 87-96, 2000

Fishman, J. Imaging in Blunt Aortic and Great Vessel Trauma. Journal of Thoracic Imaging. 15, 97-103, 2000Fishman, J. Imaging in Blunt Aortic and Great Vessel Trauma. Journal of Thoracic Imaging. 15, 97-103, 2000

Shanmuganathan, K, Mirvis, SE. Imaging Diagnosis of Nonaortic thoracic injury. Radiology Clinics of North America. Shanmuganathan, K, Mirvis, SE. Imaging Diagnosis of Nonaortic thoracic injury. Radiology Clinics of North America. 37 (3) 533-550. 199937 (3) 533-550. 1999

Rivas, LA, Fishman, JE, Munera, F, Bajayo, DE. Multislice CT in thoracic trauma. Radiology Clinics of north America. Rivas, LA, Fishman, JE, Munera, F, Bajayo, DE. Multislice CT in thoracic trauma. Radiology Clinics of north America. 41(3) May 200341(3) May 2003

Mirvis, SE. Diagnostic Imaging of Acute Thoracic injury. Semin Ultrsound Ct MR. 2004 April 25 (2):156-79Mirvis, SE. Diagnostic Imaging of Acute Thoracic injury. Semin Ultrsound Ct MR. 2004 April 25 (2):156-79

Macura, KJ, Szarf, G, Fishman, EK, Bluemke, DA. Role of CT and MDI in assessment of acute aortic syndromesMacura, KJ, Szarf, G, Fishman, EK, Bluemke, DA. Role of CT and MDI in assessment of acute aortic syndromes

Greenberg, MD, Rosen, LR. Evidence Based Emergency Medicine: Evaluation and diagnostic testing, Evaluation of Greenberg, MD, Rosen, LR. Evidence Based Emergency Medicine: Evaluation and diagnostic testing, Evaluation of the patient with Blunt Chest trauma: an evidence based approach. Emer. Med. Clinics NA. 17 (1) February 1999the patient with Blunt Chest trauma: an evidence based approach. Emer. Med. Clinics NA. 17 (1) February 1999

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