Prof. Mona MansourProfessor of Pulmonary Medicine

Ain Shams University

Prof. Mona MansourProfessor of Pulmonary Medicine

Ain Shams University

• Pulmonary embolism refers to embolic occlusion of the pulmonary arterial system. The majority of cases result from thrombotic occlusion and therefore the condition is frequently termed pulmonary thrombo-embolism

• Diagnosis Pulmonary embolism may be difficult because no reliable non

invasive imaging method.

• In United States: estimated incidence of PE exceeds 600.000 cases per year.

• 30% mortality if untreated.

• Mortality in treated cases 2.5%

1- Clinical assessment:

• Wells score

• Geneva score

Revised GenevascoreVariable

PointsWells score

Points variablePoints

Predisposing factorsPredisposing factors

Age >65 yrs.+1Pervious DVT or PE+1.5

Pervious DVT or PE+3Recent surgery or

immobilization+1.5

Surgery or fracture within 1 month

+2Cancer

+1

Active malignancy+2

Symptoms Symptoms

Unilateral lower limb pain+3

Haemoptysis+2Haemoptysis+1

Clinical signs Clinical signs

Heart rate 75-94 > 95 beats

+3+5

Heart rate >100 +1.5

Pain in lower limb vein at palpation and unilateral oedema

+4Clinical signs of DVTAlternative diagnosis

than PE

+3

+3Clinical probabilityTotalClinical probabilityTotal

Low Intermediate High

0-34-10> 11

Low Intermediate High

0-12-6> 7

2- Serological tests: • D Dimer (ELISA)

• Screening test in patients with low and moderate probability clinical assessment

a. Normal D-Dimer has almost 100% negative predictive value

b. Raised D-Dimer is non specific: we need further investigation

3- Radiological features:

Plain film:

Fleishner sign: Enlarged pulm. Artery (20%)

Hampton hump: Perpheral wedge of air

space opacity implies

lung infarction (20%)

Westermark sign: Regional oligaemia (10%)

Pleural effusion: 35%

Elevated diaphragm:

Nuclear medicine V/Q scan:• High probability scan is defined as two or more

unmatched segmental perfusion defects.

• Normal perfusion scan is very safe for excluding PE.

• Combination of non diagnostic V/Q scan + low clinical probability can exclude PE.

Computed Tomography with Pulmonary Angiography (CTPA):

• Acute pulmonary embolism:

• Filling defect (polo mint) sign.

• Central filling defect from thrombus surrounded by a thin rim of contrast.

• Saddle embolus

Computed Tomography with Pulmonary Angiography (CTPA):

• Chronic pulmonary embolism:

• Webs or bands

• Abrupt narrowing or complete obstruction of pulmonary arteries

Computed Tomography with Pulmonary Angiography (CTPA):

• Acute or Chronic right ventricular dysfunction:

a- Abnormal position of interventricular septum

b- RVD: LVD ratio > 1

Computed Tomography with Pulmonary Angiography (CTPA):

• Subacute to Chronic emboli:

a- Pulmonary infarction

B- Pulmonary hypertension

C- Chronic cor pulmonale

Gadolinium Enhanced Pulmonary Magnetic Resonance Angiography (MRI):

• Pulmonary arterial signs in MRA:

a- abrupt decrease

B- parenchymal sign

C- pulmonary hypertension

The use of MR venography could also help diagnosis of PE

•MRI is more expensive than VQ scan, but cheaper than angiography.

•MRI does not require hospitalization

•Non nephrotoxic

•No ionizing radiation

• Safe rapid, accurate, cost effective imaging.

Compression Ultrasonography (CUS)

•Diagnosis of DVT may indirectly suggest the diagnosis of PE

•Anticoagulants are most often the initial therapy for DVT and PE

Limitations:

•Not Definite for PE

•Normal proximal bilateral venous ultrasonography don't rule out PE

Pulmonary angiography:

•Invasive

•CT angiography offers better results, non invasive

Echo cardiography:

•In shock or hypotension, absence of echo signs of Rt. over load or dysfunction excludes PE.