Radiology Afterhours: ATAI and Interesting Cases

Transcription

1 Radiology Afterhours: ATAI and Interesting Cases Jeff Dunkle, MD February 21, 2011

2 Disclosures: I have nothing to disclose.

3 Assistant Professor of Clinical Radiology, Department of Radiology and Imaging Sciences, Indiana University School of Medicine. Section Chief, Emergency Radiology. President-elect, Indiana Radiological Society. Interests: Aortic Trauma, Staffing Operations.

4 Acute Traumatic Aortic Injury Learning objectives: Understand epidemiology and pathogenesis of ATAI. Describe spectrum of CT and CXR findings of ATAI. Understand treatment options and related anatomic considerations.

5 ATAI: Acute Traumatic Aortic Injury Spectrum of ATAI ranges from isolated intimal injury to full thickness tears. The most common type of (survivable) ATAI is laceration of the intima and media with pseudoaneurysm formation. Patients with full thickness tears (intima, media, and adventia) usually exsanguinate rapidly.

6 ATAI: Spectrum of injury: Circumferential tear: 45% Non-circumferential tear: 55% Full thickness: 35% Partial thickness: 65%

7 ATAI: Key Points Death is immediate in 80-90% of cases. Ascending aorta Full thickness tears Of those who survive long enough to be imaged: Descending aorta 50% die within 24 hours. >90% mortality if untreated. Factors affecting survivability: Co-injuries Time-to-treatment Age (>80% mortality in those > 55) ATAI is the 2 nd most common cause of death from blunt trauma.

8 ATAI: Key Points Mechanism: Blunt force deceleration and crush injuries: MVC (80%) Other (20%) Fall from height Pedestrian versus car Crush injuries

9 ATAI: MVC 10-20% of all high speed MVA fatalities due to ATAI. Incidence of ATAI associated with MVA unchanged despite increased seatbelt usage. Factors associated with increased risk of ATAI in MVC: High speed (>30mph/ 50kph) Sudden deceleration > 20 mph Head on collision versus side impact: Side impact probably has higher association with ATAI Impact of side / curtain airbags unclear Cabin intrusion

10 ATAI: Pathophysiology: Complex, likely multifactorial: Torsional stress Osseous pinch Water hammer effect

11 ATAI: Key Points Sites of injury seen at imaging: 80-90% involve the descending aorta Aortic Isthmus 5-10% involve the ascending aorta 5% involve the aorta at the diaphragm Blunt force injuries to the abdominal aorta are rare.

12 ATAI: Key Points Epidemiology: ATAI is a disease of adults. ATAI in children is rare. ATAI shows no sex, race, or geographic predilection

13 ATAI: Clinical presentation: Clinical signs and symptoms of ATAI are insensitive and nonspecific. ATAI cannot be excluded on clinical grounds. Imaging is the mainstay of diagnosis.

14 ATAI: Clinical presentation: Signs: Symptoms: Heart murmur Paraplegia Pseudocoarctation syndrome Other chest injuries High volume chest tube output Chest pain Cough Hoarseness Interscapular pain

15 Imaging of ATAI MDCT is the diagnostic test of choice for ATAI. Sensitivity >98% Specificity near 100%

16 CT and ATAI: Pros Fast Noninvasive Reliable NPV close to 100% Readily available Excellent anatomic detail Volumetric imaging Multi-planar reformats Comprehensive injury assessment One stop shopping Cons IV contrast Ionizing radiation Cost

17 Imaging of ATAI: Primary imaging modalities: CT: Mainstay of trauma imaging. CXR: Variable utility. Angiography: Useful in problem solving or complex injuries Secondary imaging modalities: Trans-esophageal Echocardiography (TEE) Excellent visualization of ascending Ao MRI: Useful in rare cases.

18 MDCT and ATAI: Technique: no consensus on specific protocol. C/A/P? Neck angio? CTA only? Delays? General considerations: Optimize technique with timeliness.

19 MDCT and ATAI: Our protocol: C/A/P with IV contrast. 130 cc standard dose, 3-4 cc/sec. 25sec/75sec standard delays for chest and abdomen/pelvis respectfully. Dual phase of upper abdomen. Isotropic data set. Review in axial, sagittal, and coronal planes. Thin sections available on workstation for problem solving.

20 Example: Typical ATAI on MDCT

21 MDCT and ATAI: Direct findings: Indirect findings: Ao luminal irregularity Mediastinal hematoma Intimal flap Concomitant injuries Pseudoaneurysm Ao contrast extravasation

22 MDCT and ATAI: Findings of ATAI: Direct: Ao luminal irregularity Intimal flap Pseudoaneurysm Contrast extravasation Indirect: Mediastinal hematoma Other injuries

23 Other typical ATAI cases:

24 Other typical ATAI cases:

25 Other typical ATAI cases:

26 Other typical ATAI cases:

27 Other typical ATAI cases:

28 Example: Not-so-typical ATAI

29 Example: Not-so-typical ATAI

30 Example: Not-so-typical ATAI

31 Example: Not-so-typical ATAI

32 ATAI: Injury at Diaphragm

33 ATAI: Ascending Ao injury:

34 ATAI: Ascending Ao injury:

35 MDCT and ATAI: Pitfalls: Ductus bump Atherosclerotic plaque, penetrating ulcers Streak artifact Cardiac motion

36 CT pitfalls: Streak artifact Motion artifact Aortic injury

37 CT pitfalls: Streak artifact Motion artifact Normal

38 CT Pitfalls: Ductus diverticulum: Remnant of closed ductus arteriosus. Convex bulge along the anterior undersurface of aortic isthmus. Smooth margins and obtuse angles with the aortic lumen typifies a normal ductus bump

39 Ductus Bump

40 Ductus Bump Smooth margins. Obtuse angles. No concerning associated findings. No MS hematoma No intimal flap

41 What about this?

42 Dx: PDA in an adult.

43 What about this?

44 What about this? 24 hr. follow-up with ECG-gating

45 additional imaging

46 What about this? Radiology consensus: ATAI with small pseudoaneurysm.

47 What about this? Radiology consensus: ATAI with small pseudoaneurysm. Surgical findings: No injury. Chronic atheromatous plaque with penetrating ulcer.

48 MDCT and ATAI: Pitfalls: Reassuring factors: Absence of MS hematoma Obtuse angles Smooth margins Lack of intimal flap Calcification Consider CT follow-up (+/- angio) for equivocal cases

49 CXR and ATAI:

50 CXR and ATAI: Goal: Identify evidence of MS hematoma. If CXR normal, presume no ATAI. CXR valuable for immediately life-threatening conditions, and to assess line/tube positions.

51 CXR and ATAI: Goal: Identify evidence of MS hematoma. If CXR normal, presume no ATAI. Best case scenario: 7% of ATAI have normal or near-normal CXR. Regardless of CXR findings, if mechanism suspicious, CT evaluation is warranted.

52 CXR and ATAI: Then

53 CXR and ATAI: Now

54 CXR and ATAI: Most aortic injuries are associated with mediastinal hematoma. NPV near 100% PPV only ~20% The presence of a ATAI may or may not result in mediastinal hematoma. An abnormal CXR correlates poorly with the presence of ATAI.

55 CXR findings of ATAI: Indistinct or abnormal Ao contour Obscuration of the AP window Widened L (or R) paraspinal stripe Deviation of support tubes and trachea to R Superior mediastinal widening (>8cm) L sided pleural fluid collections/apical capping 1st or 2nd rib fractures

56 ATAI?

57 ATAI: Findings of ATAI: Direct: Ao luminal irregularity Intimal flap Pseudoaneurysm Contrast extravasation Indirect: Mediastinal hematoma Other injuries

58 ATAI: Minimal Aortic Injury What does minimal mean? Low grade ATAI. Injury Isolated to intima. No indirect findings (except those attributable to concomitant injury).

59 Minimal Aortic Injury: Where did it come from?

60 ATAI: Minimal Aortic Injury Compromise 10% of ATAI % may be unapparent on angiography. Conservative therapy becoming more common.

61 ATAI: Minimal Aortic Injury Natural history varies: Resolve How quickly? Stabilize Worsen As many as 50% may progress to pseudoaneurysm. Recommend: CT follow-up.

62 ATAI: Minimal Aortic Injury

63 Treatment of ATAI: Open surgical repair Endovascular therapy

64 Treatment of ATAI Morbidity and Mortality: Surgery; Morality: % Paraplegia: % Complications: % Endovascular: Mortality: % Paraplegia: 0-0.8% Complications: %

65 Treatment of ATAI: Complications Surgery Death Paraplegia Stroke Upper extremity ischemia Other perioperative complications. Endograft Endoleak Infection Stent failure Stent migration Death Stroke Upper extremity ischemia Paraplegia Access site complications

66 Treatment of ATAI: Surgery Pros: Established technique Morbidity stats improving Definitive therapy Long term data available Cons: Big, complicated surgery Concomitant injuries complicate pre-surgical planning. Historically non-trivial paraplegia rates

67 Treatment of ATAI: Endograft Pros: Much simpler procedure than open repair. Quick. Can be more easily coordinated with treatment of other injuries. Cons: Long term data unavailable. Equipment limitations.

68 Treatment of ATAI Pre-endograft placement: What to include in CT report? Aortic arch anatomy and variation if present Vertebral artery dominance Pre-existent stenosis, atherosclerotic disease Post-operative changes (CABG) Measure Ao below and above injury Proximity to LSA origin (1.5-2cm preferable) Injury length

69 Acute Traumatic Aortic Injury Learning objectives: Understand epidemiology and pathogenesis of ATAI. Describe spectrum of CT and CXR findings of ATAI. Understand treatment options and related anatomic considerations.

70 ATAI in the 21 st century.

71 ATAI in the 23 rd Century?

72 Thank you.

73 References: 1.Creasy JD, Chiles C, Routh WD, Dyer RB. Overview of Traumatic Injury of the Thoracic Aorta. RadioGraphics 1997; Jan-Feb; 17(1): Fishman JE, Nuñez D Jr, Kane A, Rivas LA, Jacobs WE. Direct versus Indirect Signs of Traumatic Aortic Injury Revealed by Helical CT: Performance Characteristics and Interobserver Agreement. AJR Am J Roentgenol 1999; 172(4): Malhotra AK, Fabian TC, Croce MA, Weiman DS, Gavant ML, Pate JW. Minimal Aortic Injury: A Lesion associated with Advancing Diagnostic Techniques. J Trauma 2001; 51: Steenburg SD, Ravenel JG, Ikonomidis JS, Schonholz C, Reeves S. Acute Traumatic Aortic Injury: Imaging Evaluation and Management. Radiology 2008; 248: Alonso RC, Nacenta SB, et al. Kidney in Danger: CT Findings in Blunt and Penetrating Renal Trauma. RadioGraphics 2009; 29: Linsenmaier U, Wirth S, et al. Diagnosis and Classification of Pancreatic and Duodenal Injuries in Emergency Radiology. RadioGraphics 2008; 28: Hamilton, JD, Kumaraval M, Censullo ML, et al. Multidetector CT Evaluation of Active Extravasation of Blunt Abdominal and Pelvic Trauma Patients. RadioGraphics 2208; 28: Vu M, Anderson SW, et al. CT of blunt abdominal and pelvic vascular injury. Emergency Radiology 2010; 17: Kaewlai R, Avery LL, et al. Multidetector CT of Blunt Thoracic Trauma. RadioGraphics 2008; 28: Daly KP, Ho CP, et al. Traumatic Retroperitoneal Injuries; Review of Multidetector CT Findings. RadioGraphics 2008; 28: Prasad KR, Kumar A, et al. CT in post-traumatic hypoperfusion complex--a pictorial review. Emergency Radiology, online Publication: 23 December Yoon W, Yong YJ, et al. CT in Blunt Liver Trauma. RadioGraphics 2005; 25: Mirvis SE, Whitley NO, Gens DR, Blunt Splenic Trauma in Adults: CT-based classification and correlation with prognosis and treatment. Radiology 1989; 171: Shanmuganathan K, et al. Nonsurgical Manaement of Blunt Splenic Injury: Use of CT Criteria to Select Patients for Splenic Arteriography and Potential Endovascular Therapy. Radiology 2000; 217: Morgan TA, Steenburg SD, et al. Acute Traumatic Aortic Injuries: Posttherapy Multidetector CT Findings. RadioGraphics 2010; 30: Neschis DG, Scalea TM, et al. Blunt Aortic Injury. NEJM 2008;