Chronic PE

Chronic PE

1. RadioGraphics 2009; 29:31–53
CT Diagnosis ofCT Diagnosis of
Chronic Pulmonary Chronic Pulmonary
ThromboembolismThromboembolism
Castañer et al :Castañer et al :Department of Radiology, Universitari Parc TaulDepartment of Radiology, Universitari Parc Taulํํ-UAB, Barcelona-UAB, Barcelona
Present by Ekkasit S.

2. IntroductionIntroduction
•Chronic pulmonary thromboembolism is mainly a
consequence of incomplete resolution of pulmonary
thromboembolism.
•Increased vascular resistance due to obstruction of
the vascular bed leads to chronic thromboembolic
pulmonary hypertension .

3. IntroductionIntroduction
•The prevalence of chronic thromboembolic
pulmonary hypertension in the general population
has yet to be accurately determined and may have
been significantly underestimated.
•Recent data : 4% after acute PE.
•Chronic thromboembolic pulmonary hypertension is
clearly more common than previously was thought,
and misdiagnosis is common because patients
often present with nonspecific symptoms .

4. IntroductionIntroduction
•Symptoms
–Nonspecific & related to the development of
pulmonary hypertension.
–Symptoms worsen as the RV functional deteriorates.
–Chronic thromboembolic pulmonary hypertension
often is identified during the diagnostic work-up in
patients with unexplained pulmonary hypertension
radiologists must be aware of its radiologic
manifestations because it is a treatable cause of
pulmonary hypertension in some patients

5. •Risk Factors and Clinical
Manifestations
•Pathogenesis
•CT Technique
•CT Features of Chronic Pulmonary
Thromboembolism
–Vascular Signs
–Parenchymal Signs
•Differential Diagnosis
•Diagnostic Evaluation
•Treatment

6. Risk Factors & Clinical ManifestationsRisk Factors & Clinical Manifestations
Risk FactorsRisk Factors
•Women ( slightly more frequently )
•Underlying malignant, cardiovascular, or pulmonary
disease are at increased risk
•Other reported risk factors
–Splenectomy
–Ventriculoatrial shunts
–Chronic inflammatory disorders
–Myeloproliferative syndromes
–Ethic (more prevalent in Asian patients)

7. Risk Factors & Clinical ManifestationsRisk Factors & Clinical Manifestations
Pengo V et al. Pengo V et al. (N Engl J Med 2004)(N Engl J Med 2004)
“ “ Incidence of chronic thromboembolic pulmonary
hypertension after pulmonary embolism ””
Factors associated with increased risk of chronic
thromboembolic pulmonary hypertension
•Multiple episodes of pulmonary embolism
•Larger perfusion defect
•Younger age
•Idiopathic manifestation of pulmonary thromboembolism

8. Risk Factors & Clinical ManifestationsRisk Factors & Clinical Manifestations
Chronic thromboembolic pulmonary Chronic thromboembolic pulmonary
hypertensionhypertension
•Lupus anticoagulant is detected in approximately
10% of patients
•Plasma levels of factor VIII and antiphospholipid
antibodies are elevated

9. Risk Factors & Clinical ManifestationsRisk Factors & Clinical Manifestations
•Symptoms are nonspecific and are related to the
development of pulmonary hypertension.
•The extent of vascular obstruction is a major
determinant of the severity of pulmonary
hypertension.

10. Risk Factors & Clinical ManifestationsRisk Factors & Clinical Manifestations
Clinical Manifestations Of chronic Clinical Manifestations Of chronic
thromboembolic pulmonary hypertensionthromboembolic pulmonary hypertension
May be asymptomatic for several years
•Recurrent acute or progressive exertional dyspnea
•Chronic nonproductive cough
•Atypical chest pain
•Tachycardia
•Syncope
•Cor pulmonale

11. Risk Factors & Clinical ManifestationsRisk Factors & Clinical Manifestations
Clinical Manifestations Of chronic Clinical Manifestations Of chronic
thromboembolic pulmonary hypertensionthromboembolic pulmonary hypertension
•Pulmonary arterial pressure is elevated
•Right atrial pressures are high
•Cardiac output is reduced
•Pulmonary capillary wedge pressures are normal

12. •Risk Factors and Clinical
Manifestations
•Pathogenesis
•CT Technique
•CT Features of Chronic Pulmonary
Thromboembolism
–Vascular Signs
–Parenchymal Signs
•Differential Diagnosis
•Diagnostic Evaluation
•Treatment
•Conclusions

13. PathogenesisPathogenesis
“In more than 90% of patients includes
total resolution or resolution with
minimal residual and restoration of
normal pulmonary hemodynamics
within 30 days after treatment”

14. PathogenesisPathogenesis
•Early resolution of pulmonary vascular
obstruction occurs by two mechanisms:
–Mechanical fragmentation.
–Endogenous fibrinolysis.

15. PathogenesisPathogenesis
•The pathogenesis of chronic
thromboembolism is still unclear.
•Extensive analyses of plasma proteins
in patients with chronic thromboembolic
pulmonary hypertension have shown no
abnormalities in fibrinolysis.

16. Various possible results of disturbed resolution of a thrombus

17. PathogenesisPathogenesis
•The bronchial and nonbronchial
systemic circulation is markedly
increased.
–To maintain pulmonary blood flow in the
presence of vessel obstruction

18. •Risk Factors and Clinical
Manifestations
•Pathogenesis
•CT Technique
•CT Features of Chronic Pulmonary
Thromboembolism
–Vascular Signs
–Parenchymal Signs
•Differential Diagnosis
•Diagnostic Evaluation
•Treatment
•Conclusions

19. CT TechniqueCT Technique
Acute PEAcute PE
•MDCT
•Trigger threshold
–Main PA
–120 HU
•Contrast material
–100 mL (iopromide,
Ultravist 300)
–4 mL/sec
Chronic PEChronic PE
•MDCT
•Trigger threshold
–Main PA
–200 HU
•Contrast material
–100 mL (iopromide,
Ultravist 300)
–4 mL/sec

20. 100700Pulmonary thromboembolism-
specific window
40350Mediastinum window
-6001500Lung window
window
level
window
width
CT TechniqueCT Technique

21. CT TechniqueCT Technique
•Multiplanar
reformatted
images
•Maximum
intensity
projection
images
Chronic pulmonary thromboembolism in a 47-year-old man. Coronal MIP image

22. •Risk Factors and Clinical
Manifestations
•Pathogenesis
•CT Technique
•CT Features of Chronic Pulmonary
Thromboembolism
–Vascular Signs
–Parenchymal Signs
•Differential Diagnosis
•Diagnostic Evaluation
•Treatment
•Conclusions

23. CT Features of ChronicCT Features of Chronic
Pulmonary ThromboembolismPulmonary Thromboembolism
•Vascular signsVascular signs
–Direct pulmonary artery signs
–Signs due to pulmonary hypertension
–Signs due to systemiccollateral supply
•Parenchymal signsParenchymal signs
–Scars
–A mosaic perfusion pattern
–Focal groundglass opacities
–Bronchial dilatation

24. Pulmonary Arterial SignsPulmonary Arterial Signs
•Complete ObstructionComplete Obstruction
–Abrupt decrease in vessel diameter
–Absence of contrast material in the vessel segment
distal to the total obstruction
–Lung window : segmental and subsegmental vessels
that are abnormally small in comparison with the
accompanying bronchi.

25. Chronic pulmonary thromboembolism in a 65-year-old man with a
history of multiple episodes of acute pulmonary thromboembolism.
(a) Axial contrast-enhanced CT, (b) Axial CT scan (lung window)

26. Pulmonary Arterial SignsPulmonary Arterial Signs
•Partial Filling DefectsPartial Filling Defects
–Abrupt vessel narrowing.
•Recanalization
•Organized thrombus
–Poststenotic dilatation or aneurysm.
–Thrombus :
•Obtuse angles to arterial wall.
•Band or web: most frequently in lobar or segmental arteries
, rarely in the main pulmonary artery.
•Calcifications within chronic thrombi (in a small number of
patients)

27. Chronic pulmonary thromboembolism in a 47-year-old man.
Coronal 10-mm-thick maximum intensity projection image.

28. Chronic pulmonary thromboembolism in an 80-year-old woman with a history of
acute pulmonary thromboembolism.
Axial contrast-enhanced CT scan.

29. Chronic pulmonary thromboembolism in an 80-year-old woman with a history of
acute pulmonary thromboembolism.
Axial contrast-enhanced CT scan.

30. Chronic pulmonary thromboembolism in an 80-year-old woman with a history of
acute pulmonary thromboembolism.
Oblique coronal 30-mm-thick maximum intensity projection CT image.

31. Chronic pulmonary thromboembolism in an 80-year-old woman with a history of
acute pulmonary thromboembolism.
Oblique coronal 10-mmthick maximum intensity projection CT image

32. Residual band from a pulmonary thrombus in an 83-year-old woman with dyspnea.
Axial contrast-enhanced CT image .

33. Residual band from a pulmonary thrombus in an 83-year-old woman with dyspnea.
Coronal 10-mm-thick maximum intensity projection CT image.

34. Chronic pulmonary thromboembolism in an 86-year-old woman.
Axial contrast-enhanced CT scan, (width, 1100 HU; level, 100 HU)

35. CT Features of ChronicCT Features of Chronic
Pulmonary ThromboembolismPulmonary Thromboembolism
•Vascular signsVascular signs
–Direct pulmonary artery signs
–Signs due to pulmonary hypertension
–Signs due to systemiccollateral supply
•Parenchymal signsParenchymal signs
–Scars
–A mosaic perfusion pattern
–Focal groundglass opacities
–Bronchial dilatation

36. Signs of pulmonary hypertension Signs of pulmonary hypertension
•Main pulmonary artery diameter more than 29 mm.
•Diameter of MPA : Aorta > 1:1 = strong correlation
with elevated pulmonary artery pressure, especially in
patients younger than 50 years.
•Central pulmonary arteries in patients with chronic
thromboembolic pulmonary hypertension often are
asymmetric in size.
•Atherosclerotic calcification of arterial wall.
•Tortuous pulmonary vessels.

37. Main pulmonary artery diameter more than 29 mm

38. Chronic pulmonary thromboembolism and pulmonary hypertension in a 42-year-old man.
Axial contrast-enhanced CT scan.

39. Chronic pulmonary thromboembolism in an 80-year-old woman with a history of
acute pulmonary thromboembolism.
Oblique coronal 10-mmthick maximum intensity projection CT image

40. Signs of pulmonary hypertension Signs of pulmonary hypertension
•RV myocardial thickness greater than 4 mm.
•RV dilatation : a ratio of more than 1:1 between the
RV:LV diameters. (At widest points)
•Mild pericardial thickening or a small pericardial
effusion.
•May have enlarged lymph nodes.
–At histologic examination of these enlarged nodes, a vascular
transformation of the lymph node sinus may be seen, often in
association with sclerosis of varying degrees

41. Right heart abnormalities secondary to chronic thromboembolic pulmonary
hypertension in a 47-year-old man.
Axial contrast-enhanced CT scan.

42. Right heart abnormalities secondary to chronic thromboembolic pulmonary
hypertension in a 47-year-old man.
Axial contrast-enhanced CT scan.

43. CT Features of ChronicCT Features of Chronic
Pulmonary ThromboembolismPulmonary Thromboembolism
•Vascular signsVascular signs
–Direct pulmonary artery signs
–Signs due to pulmonary hypertension
–Signs due to systemic collateral supply
•Parenchymal signsParenchymal signs
–Scars
–A mosaic perfusion pattern
–Focal groundglass opacities
–Bronchial dilatation

44. Collateral Systemic SupplyCollateral Systemic Supply
•Bronchial flow may represent almost 30% of the
systemic blood flow ( Normal = 1-2%).
•Systemic-to-pulmonary arterial anastomoses develop
beyond the level of obstruction.
•CT findings of bronchial artery hypervascularization.
–Abnormal dilatation of the proximal portion of the bronchial
arteries (diameter of more than 2 mm) and arterial tortuosity.

45. Collateral Systemic SupplyCollateral Systemic Supply
•Found more frequently in patients with chronic
thromboembolic pulmonary hypertension (73%) than
in patients with idiopathic pulmonary hypertension
(14%).
•Lower mortality rate after pulmonary
thromboendarterectomy.
•Development of systemic hypervascularization may
also be responsible for hemoptysis in these patients

46. Chronic pulmonary thromboembolism in a 47-year-old man.
Coronal 10-mm-thick maximum intensity projection image.

47. Chronic pulmonary thromboembolism in an 80-year-old woman with a history of
acute pulmonary thromboembolism
Axial contrast-enhanced CT scan .

48. Chronic pulmonary thromboembolism in an 80-year-old woman with a history of
acute pulmonary thromboembolism
Oblique coronal 20-mm-thick maximum intensity projection CT image

49. Chronic pulmonary thromboembolism in a 47-year-old man with multiple episodes of acute
pulmonary thromboembolism.
Coronal 30-mm-thick maximum intensity projection CT image.

50. CT Features of ChronicCT Features of Chronic
Pulmonary ThromboembolismPulmonary Thromboembolism
•Vascular signsVascular signs
–Direct pulmonary artery signs
–Signs due to pulmonary hypertension
–Signs due to systemic collateral supply
•Parenchymal signsParenchymal signs
–Scars
–A mosaic perfusion pattern
–Focal groundglass opacities
–Bronchial dilatation

51. Parenchymal SignsParenchymal Signs
•Scars from prior pulmonary infarctions
–May appear as parenchymal bands, wedge-shaped
opacities, peripheral nodules, cavities, or irregular peripheral
linear opacities.
–Parenchymal scars often occur in multiples, generally are
found in the lower lobes, and often are accompanied by
pleural thickening.

52. Chronic pulmonary thromboembolism in an 85-year-old woman, 2 years after an
episode of massive acute thromboembolism
CT scan (lung window)

53. Chronic pulmonary thromboembolism in a 65-year-old man with a history of multiple episodes of
acute pulmonary thromboembolism.
Axial CT scan (lung window)

54. Chronic pulmonary thromboembolism in an 46-year-old man.
CT scan (lung window)

55. Chronic pulmonary thromboembolism in a 65-year-old man
CT scan (lung window)

56. Parenchymal SignsParenchymal Signs
•A mosaic pattern of perfusion
–Sharply demarcated regions of decreased and increased
attenuation because of irregular perfusion.
–Much more commonly in patients with chronic
thromboembolic pulmonary hypertension than in patients with
idiopathic pulmonary hypertension
•Focal areas of ground-glass attenuation
– Systemic perfusion of the peripheral pulmonary arterial bed
accounts for the presence of isolated focal areas of ground-
glass attenuation.

57. Chronic pulmonary thromboembolism in an 85-year-old woman, 2 years after an
episode of massive acute thromboembolism
CT scan (lung window)

58. Chronic pulmonary thromboembolism in a 65-year-old man
CT scan (lung window)

59. Chronic pulmonary thromboembolism in an 80-year-old woman with a history of
acute pulmonary thromboembolism
Coronal 20-mm-thick maximum intensity projection CT image.

60. Parenchymal SignsParenchymal Signs
•Air trapping
–Arakawa et al : Significant associations between
•The appearance of air trapping and the presence of a proximal
arterial stenosis or clot.
•The extent of air trapping and the degree of impairment of
pulmonary function of the small airways.
–Seen in two thirds of patients with chronic thromboembolic
pulmonary hypertension.
–Commonly seen in areas of hypoperfusion.
•Bronchial dilatation

61. Chronic pulmonary thromboembolism in an 82-year-old woman.
Axial CT scan (lung window) (a) inspiration (b) expitation

62. Chronic pulmonary thromboembolism in an 82-year-old woman.
(a) Axial CT scan (lung window) , (b) Axial contrast-enhanced CT scan

63. CT Features of ChronicCT Features of Chronic
Pulmonary ThromboembolismPulmonary Thromboembolism
•Vascular signsVascular signs
–Direct pulmonary artery signs
–Signs due to pulmonary hypertension
–Signs due to systemic collateral supply
•Parenchymal signsParenchymal signs
–Scars
–A mosaic perfusion pattern
–Focal groundglass opacities
–Bronchial dilatation

64. •Risk Factors and Clinical
Manifestations
•Pathogenesis
•CT Technique
•CT Features of Chronic Pulmonary
Thromboembolism
–Vascular Signs
–Parenchymal Signs
•Differential Diagnosis
•Diagnostic Evaluation
•Treatment
•Conclusions

65. Differential DiagnosisDifferential Diagnosis
1.Idiopathic Pulmonary Hypertension.
2.Differentiation of Acute and Chronic
Thromboembolism.
3.Proximal Interruption of the Pulmonary
Artery.
4.Takayasu Arteritis.
5.Primary Sarcoma of the Pulmonary Artery.
6.Bronchial Abnormalities.

66. Differential DiagnosisDifferential Diagnosis
•Idiopathic Pulmonary Idiopathic Pulmonary
Hypertension.Hypertension.
–Enlargement of collateral arteries ( 73% in
chronic PE VS 14% in idiopathic pulmonary
hypertension)
–Mosaic lung attenuation is seen frequently in
patients with chronic thromboembolic pulmonary
hypertension and is hardly ever seen in idiopathic
pulmonary hypertension.
–Lung infarcts are rarely seen in patients with
idiopathic pulmonary hypertension.

67. Differential DiagnosisDifferential Diagnosis
•Differentiation of Acute and Differentiation of Acute and
Chronic Thromboembolism.Chronic Thromboembolism.
–Acute and chronic thromboembolism commonly
coexist.

68. Differential DiagnosisDifferential Diagnosis
Mean attenuation in chronic PE (87
HU ± 30) is higher than acute PE
(33 HU ± 15).
Dilated bronchial arteries.
Nonobstructive eccentric filling
defect forms obtuse angles with the
vessel wall.
Nonobstructive eccentric filling
defect forms acute angles with the
vessel wall.
Decreased Diameter of pulmonary
artery.
Increased Diameter of pulmonary
artery.
Chronic PEChronic PEAcute PEAcute PE

69. Evolution of chronic occlusive pulmonary thromboembolism from acute embolism in a 40-year-old man.
(b)Axial contrast-enhanced CT scan shows acute embolism in the left lower lobe, with increased arterial
diameters (arrows) due to impacted thrombi.
(c)Axial contrast-enhanced CT scan obtained at the same level as a, 1 year later, when the patient presented
with dyspnea, shows a permanent reduction in the diameters of the left lower lobe arteries (arrows)
because of thrombus organization and retraction, findings indicative of chronic thromboembolism.

72. Differential DiagnosisDifferential Diagnosis
•Proximal Interruption of the Proximal Interruption of the
Pulmonary ArteryPulmonary Artery
–smooth, abrupt tapering of the pulmonary artery,
without endoluminal changes.
–Only 3% presence multiple bilateral arterial
abnormalities.

73. Unilateral proximal interruption of the right pulmonary artery in a 52-year-old woman
with progressive dyspnea.
Axial contrast-enhanced CT scan .

74. Differential DiagnosisDifferential Diagnosis
•Takayasu ArteritisTakayasu Arteritis
–Frequently affects the aorta and its major branches.
–Pulmonary artery involvement occurs in 50%–80% of
patients and is a manifestation of late-stage disease.
–Findings of wall thickening in the aorta and aortic branches
–Stenosis and occlusion, mainly involve segmental and
subsegmental a. ,less involve lobar or main pulmonary a.

75. Late-stage Takayasu arteritis with right pulmonary artery involvement in a 63-year-old woman.
(a) Axial contrast-enhanced CT scan (b) at the level of the supra-aortic trunks

76. Differential DiagnosisDifferential Diagnosis
•Primary Sarcoma of the Primary Sarcoma of the
Pulmonary a.Pulmonary a.
–Rare.
–Most invole: The main or proximal pulmonary a.
–Filling defect frequently spans the entire luminal diameter of
the artery.
–Extension into the lung parenchyma or mediastinum
–Delayed enhancement
–Chong et al reported : positive uptake of fluorine 18
fluorodeoxyglucose at PET CT

77. Pulmonary artery sarcoma in a 70-yearold man with dyspnea.
Axial contrast-enhanced CT

78. Differential DiagnosisDifferential Diagnosis
•Bronchial AbnormalitiesBronchial Abnormalities
–Bronchial dilatation is a well-known hallmark of chronic
obstructive pulmonary disease (COPD).
–Mucus-filled dilated bronchi, pulmonary infiltrates, or both are
usually present.

79. •Risk Factors and Clinical
Manifestations
•Pathogenesis
•CT Technique
•CT Features of Chronic Pulmonary
Thromboembolism
–Vascular Signs
–Parenchymal Signs
•Differential Diagnosis
•Diagnostic Evaluation
•Treatment

80. Diagnostic EvaluationDiagnostic Evaluation
•Transthoracic echocardiographyTransthoracic echocardiography
–Diagnosis of pulmonary hypertension.
–Exclude other cardiac causes of pulmonary
hypertension.

81. Diagnostic EvaluationDiagnostic Evaluation
•Ventilation-Perfusion ScintigraphyVentilation-Perfusion Scintigraphy
–Tunariu et al : V/Q scintigraphy has a higher
sensitivity than CTPA.
–Not determination of the magnitude, location or
extent of disease.
–Cannot predict its surgical operability.
–Not help identify other causes of pulmonary
hypertension

82. Diagnostic EvaluationDiagnostic Evaluation
•Right Heart Catheterization and Right Heart Catheterization and
Pulmonary AngiographyPulmonary Angiography
–Standard for diagnosis chronic thromboembolic
pulmonary hypertension.
–Determination of the postoperative prognosis.
–Gives an indication of surgical operability.
–However, in the future, pulmonary angiography
probably will be performed only when an
adequate surgical roadmap has not been
provided by CT and MRI

83. Diagnostic EvaluationDiagnostic Evaluation
•CT AngiographyCT Angiography
–Diagnosing chronic thromboembolic pulmonary
hypertension
–Determining surgical operability
–More sensitive than conventional angiography in depicting
the central thrombotic disease.
–Equally sensitive to MRA in depicting the disease at the
segmental level
–Superior to MRA for the depiction of patent subsegmental
a. and intraluminal webs and for the direct demonstration
of thrombotic wall thickening

84. Diagnostic EvaluationDiagnostic Evaluation
•MR ImagingMR Imaging
–Characterization of the impairment of function in the right
side of the heart.
–Estimation of flow in the bronchial arteries.
–It also may play an important role in postoperative follow-
up
–Cannot take the place of conventional angiography and
right heart catheterization for the preoperative
determination of pulmonary vascular resistance and mean
pulmonary artery pressure

85. •Risk Factors and Clinical
Manifestations
•Pathogenesis
•CT Technique
•CT Features of Chronic Pulmonary
Thromboembolism
–Vascular Signs
–Parenchymal Signs
•Differential Diagnosis
•Diagnostic Evaluation
•Treatment

86. TreatmentTreatment
•The primary treatment for chronic thromboembolic pulmonary
hypertension is surgical pulmonary thromboendarterectomy.
–Hemodynamic or ventilatory impairment at rest or exercise.
–Marked pulmonary hypertension develops during exercise.
•CTA features predictive of a good response.
–Evidence of extensive central vessel disease and limited small-
vessel involvement .
– Dilated bronchial arteries.
•Placement of a filter in the inferior vena cava is recommended.
• Lifelong anticoagulant therapy