Pulmonary angiography is the angiographic opacification of the main and pulmonary artery and its branches. By radiographic techniques, it is possible to picturize up to seventh order pulmonary arteries. Newer imaging modalities like CT and MR angiography are fast emerging as superior alternatives to angiography but there is a need to hold on to this modality in view of its therapeutic potential.
Indications
1) Pulmonary embolism — In view of the limited ability of CT and MRA to detect sub segmental emboli, pulmonary angiography with direct super selective injections may offer better resolution.
2) Vasculitis
3) Congenital abnormalities of pulmonary arteries
4) Acquired abnormalities of pulmonary arteries
5) Tumour encasement
6) Pulmonary vascular malformation
Technical Requirements
Digital subtraction pulmonary angiography with selective pulmonary arterial injections is vastly superior to conventional cut film angiography in all aspects except in resolution.
Contraindications
Absolute: None
Relative
1) Individuals with LBBB may develop complete heart block due to catheter trauma
2) Pulmonary hypertension
3) Anaphylactoid reaction to intravenous contrast
4) Patients on amiodarone
Venous Access
The femoral vein is the preferred venous access site. However, if there is proximal thrombus, then the alternative venous access sites are right or left internal jugular vein, right or left basilic vein in the antecubital fossa.
Pulmonary Catheterization
A 6F or 7F pulmonary catheter is placed over the wire in the pulmonary artery. A sidearm sheath can be left in place if it is intended to follow the study with thrombolytic therapy.The commonly used catheters for pulmonary angiography are:
1) Straight body pigtail catheter
2) Angled pigtail catheter
3)Balloon catheter
Haemodynamic Assessment
This should be done prior to contrast injection.
1) All right heart and pulmonary artery pressures.
2) Damping of pressure in MPA may indicate massive embolism.
3) Pulmonary artery wedge pressure can be measured by using a balloon floatation catheter.
Contrast Media
It is recognized that contrast media can itself generate thrombus and cause embolism. A low osmolar iodinated contrast medium is preferable. For right and left pulmonary arteries, 40 to 50ml of contrast at 20 to 25 ml/sec is required. When digital subtraction angiography is used, 25 ml of contrast is often enough. Balloon occlusion angiography of segmental vessels requires 5 to 10ml of contrast.
Filming
Two views of each lung are performed — frontal view and 45 ° right (for right lung) and left (for left lung) posterior oblique views. For most indications, filming at 6 images per second is sufficient.
Anatomy and Physiology
The anatomy and physiology of the pulmonary arteries has already been dealt with in other sections and will not be repeated here.
Angiographic Findings and Interpretation
Pulmonary angiography is useful in the following clinical scenarios:
1) Pulmonary artery stenosis
2) Pulmonary arteriovenous communications
3) Diffuse or focal attenuation of pulmonary vessels
4) Intraluminal abnormalities:
a)Acute pulmonary thromboembolism
b) Chronic pulmonary thromboembolism
c)Pulmonary vascular neoplasms
d) Pulmonary artery aneurysms
5)Miscellaneous:
a)Inflammation—infectious and non-infectious inflammatory diseases.
b) Hemorrhage—hemoptysis
c)Foreign bodies
Indications
1) Pulmonary embolism — In view of the limited ability of CT and MRA to detect sub segmental emboli, pulmonary angiography with direct super selective injections may offer better resolution.
2) Vasculitis
3) Congenital abnormalities of pulmonary arteries
4) Acquired abnormalities of pulmonary arteries
5) Tumour encasement
6) Pulmonary vascular malformation
Technical Requirements
Digital subtraction pulmonary angiography with selective pulmonary arterial injections is vastly superior to conventional cut film angiography in all aspects except in resolution.
Contraindications
Absolute: None
Relative
1) Individuals with LBBB may develop complete heart block due to catheter trauma
2) Pulmonary hypertension
3) Anaphylactoid reaction to intravenous contrast
4) Patients on amiodarone
Venous Access
The femoral vein is the preferred venous access site. However, if there is proximal thrombus, then the alternative venous access sites are right or left internal jugular vein, right or left basilic vein in the antecubital fossa.
Pulmonary Catheterization
A 6F or 7F pulmonary catheter is placed over the wire in the pulmonary artery. A sidearm sheath can be left in place if it is intended to follow the study with thrombolytic therapy.The commonly used catheters for pulmonary angiography are:
1) Straight body pigtail catheter
2) Angled pigtail catheter
3)Balloon catheter
Haemodynamic Assessment
This should be done prior to contrast injection.
1) All right heart and pulmonary artery pressures.
2) Damping of pressure in MPA may indicate massive embolism.
3) Pulmonary artery wedge pressure can be measured by using a balloon floatation catheter.
Contrast Media
It is recognized that contrast media can itself generate thrombus and cause embolism. A low osmolar iodinated contrast medium is preferable. For right and left pulmonary arteries, 40 to 50ml of contrast at 20 to 25 ml/sec is required. When digital subtraction angiography is used, 25 ml of contrast is often enough. Balloon occlusion angiography of segmental vessels requires 5 to 10ml of contrast.
Filming
Two views of each lung are performed — frontal view and 45 ° right (for right lung) and left (for left lung) posterior oblique views. For most indications, filming at 6 images per second is sufficient.
Anatomy and Physiology
The anatomy and physiology of the pulmonary arteries has already been dealt with in other sections and will not be repeated here.
Angiographic Findings and Interpretation
Pulmonary angiography is useful in the following clinical scenarios:
1) Pulmonary artery stenosis
2) Pulmonary arteriovenous communications
3) Diffuse or focal attenuation of pulmonary vessels
4) Intraluminal abnormalities:
a)Acute pulmonary thromboembolism
b) Chronic pulmonary thromboembolism
c)Pulmonary vascular neoplasms
d) Pulmonary artery aneurysms
5)Miscellaneous:
a)Inflammation—infectious and non-infectious inflammatory diseases.
b) Hemorrhage—hemoptysis
c)Foreign bodies
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