aortography

By :Sudil PaudyalB.Sc. MIT 4th batch, IOM

AORTOGRAPHY

Outlines

• Angiography procedure• Equipments for angiography• Catheterization technique for angiography• Angiographic team• Anatomy of aorta• Aortographic procedures• Other arteriograms

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Angiography

• Blood vessels not normally visible in conventional radiography because no natural contrast exists between them and other soft tissues of the body.

• Must be filled with a radiopaque contrast medium to delineate them for radiography.

• Angiography- general term that describes the radiologic examination of vascular structures after the introduction of an iodinated contrast medium or gas.

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Types of Angiographic Procedures• Arteriography-• Venography• Angiocardiography• Lymphography• Examinations are more precisely named for the specific blood

vessel opacified and the method of injection.

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Contrast media

• Non ionic- HOCM or LOCM

• Injeciton parameters vary according to the procedure being performed.


Injection Technique

• Selective injection through a catheter involves placing the catheter within a vessel so that the vessel and its major branches are opacified.

• In selective injection, the catheter tip is positioned into the orifice of a specific artery so that only that specific vessel is injected.

• A CM may be injected by hand with a syringe, but ideally should be injected by an automatic injector.

• The major advantage of automatic injectors is that a specific quantity of contrast medium can be injected during a predetermined period of time.


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Equipment

Fig: Biplanar angiographic equipment04/11/2023 Aortography-sudil

Tray and sterile supplies

• A sterile tray contains the basic equipment necessary for a Seldinger catheterization of a femoral artery.

• Include the following:1.Hemostats2.Prep sponges and antiseptic solution3.Scalpel blade4.Syringe and needle for local anesthetic5.Basins and medicine cup6.Sterile drapes and towels7.Band-Aids8.Sterile image intensifier cover


Additional equipments

• Syringes

• Connective tubing

• Disposable fluids reservoir

• Catheters

• Guide wires

• Dilators

• Arterial needles 904/11/2023 Aortography-sudil

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Needles

• Vascular access needles

• Size based on external diameter of needle

• Allows for appropriate Guidewires matching– So internal diameter

must also be known


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Guidewires

• Used as a platform over which a catheter is to be advanced

• Once positioned guidewire is fixed and catheter is advanced until it meets the tip of the guidewire.

• Mostly constructed on stainless steel & coated with Teflon


Catheters• Angiographic catheters are made of pliable plastic that allows

them to straighten for insertion over the guide wire. • They normally resume their original shape after the guidewire is

withdrawn. • Catheters with a bent tip are designed for maneuverability into

artery origins for selective injections.


• Common angiographic catheters range in size from 4 Fr to 7 Fr ,although even smaller or larger sizes may be used.

• Have side holes that affect the flow of CM and pressure exerted to the catheter. Numerous sideholes are especially beneficial in a large vessel such as aorta.


Catheterization

• Preferred over needle injection of the media.• The advantages are as follows:I. The risk of extravasation is reduced.2. Most body parts can be reached for selective injection.3. The patient can be positioned as needed.4. The catheter can be safely left in the body while radiographs

are being examined.• The femoral, axillary, and brachjal arteries are the most

commonly punctured vessels.• The transfemoral site is preferred because it is associated with

the fewest risks.


• The most widely used catheterization method is the Seldinger technique.

• Performed under sterile conditions. • The site is suitably cleaned and then surgically draped. • The pt. is given local anesthesia at the catheterization site.

• With this percutaneous technique the arteriotomy or venotomy is no larger than the catheter itself. Therefore hemorrhage is minimized.

• Patients can usually resume normal activity within 24 hours after the examination.


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Catheterization: Seldinger Technique


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Seldinger Technique: Catheters and Guidewires


Translumbar approach

• When peripheral artery sites are unavailable, sometimes a catheter may be introduced into the aorta using the translumbar aortic approach.

• For this technique, patient is positioned prone, and a special catheter introducer system is inserted percutaneously through the posterolateral aspect of the back and directed superiorly so that the catheter enters the aorta around the T 11 – T12 Ievel.


• The catheter is directed either cranially for visualization of the abdominal aorta and the renal arteries, or caudally to show the aortic bifurcation, the pelvic and leg arteries.

• Not suitable for selective catheterization because of the risk of severe retroperitoneal bleeding involved with exchange and manipulations of catheters.


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Angiography Team

• Physician, usually an interventional radiologist

• Radiologic Technologist (CIT)

• Other specialists like anesthetist, nurse.

• The CIT often assists in performing procedures that require sterile technique and may be responsible for operating monitoring devices and emergency equipment, as well as the radiographic equipment.

• Must receive adequate training for proper use of the supporting equipment , patient care techniques and sterile procedures.04/11/2023 Aortography-sudil

Aortography


• Specialized radiological procedure of imaging the aorta and its branches .

• Involves placement of a catheter in the aorta and injection of contrast material while taking radiographs.

• The aortogram was previously considered the gold standard test for the diagnosis of aortic diseases.

• Nowadays being replaced by newer imaging modalities like CT, MRI and Transoesophageal echocardiography (TEE).

Anatomy • Begins at the upper part of left ventricle where it is about 3

cm in diameter and ends diminished in size (about 1.75 cm. in diameter), at the level of L4 by dividing into the right and left common iliac arteries.

• Divided into :• Thoracic aorta

Ascending aortaArch of aortaDescending aorta

• Abdominal aorta


Variations in archVariation is common in the branches of the aortic arch, such that

the 'normal' pattern is only seen in 65% of subjects.• In 5% of subjects the left vertebral artery arises directly from

the arch of the aorta, between the origins of the left common carotid and left subclavian arteries.

• 2.7% have a common origin of the left common carotid and subclavian as a left brachiocephalic artery.

• In 2.5% the left common carotid arises from the brachiocephalic artery.

• In 0.5% an aberrant right subclavian artery arises distal to the left subclavian artery and passes to the right, posterior to the oesophagus.

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• Rare: right common carotid and subclavian arteries arising separately.

• Very rarely the common carotid is absent so that the internal and external carotid arteries arise separately from the aortic arch on one or both sides.

• The following other arteries may also arise from the aortic arch:

— One or both bronchial arteries— Inferior thyroid artery— Internal thoracic artery•The aortic isthmus is the junction of the arch of the aorta and

the descending aorta. This area is relatively fixed and is thus prone to injury with the shearing forces of blunt trauma.


Abdominal aorta


Indications


• Aortic dissections and aneurysms• Patent ductus arteriosus• Coarctation• Arteriovenous malformations• Occlusions• Atherosclerotic diseases• Congenital anomalies• Stenosis• Tumor vascularity• Prior to aneurysm repair or other surgery involving the aorta.

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Contraindications

• Previous severe reaction to contrast

• Impaired renal function

• Impaired blood clotting factors

• Inability to undergo surgical procedure


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Pre-Procedure

• PT’s are usually limited to a liquid diet and routine medications

• Adequate hydration

• An IV line placed

• History taken and vitals taken

• Informed consent


Procedure

• Aortography is usually performed with the patient in the supine position for simultaneous frontal and lateral imaging by the biplanar equipment.

• It can be mainly divided into two parts: Thoracic aortography and Abdominal aortography


Thoracic aortography

• A 5-6 Fr pigtail catheter or one capable of large volume of CM delivery .

• Approx. 90 cm in length over a standard guide wire.

Pt. position:• Depends on the area of interest.• Arch is best demonstrated with a 35 to 45° RPO position.• For lateral projections, patient's arms moved superiorly so

that they donot appear in the image.


• For all projections, central ray directed to the center of the chest at the level of T7.

• The contrast medium is injected at rates ranging from 25 to 35 ml/sec for a total volume of 50 to 70 mI.

• All radiographs must include heart, aortic arch and great vessels and allow visualization of the entire thoracic aorta, including the proximal brachiocephalic, carotid, and subclavian vessels.


Abdominal aortography

• A 4-6 Fr , 24 inch (60 cm) pigtail catheter is inserted over a standard J-tip guidewire for femoral approach, for a non- selective study.

• Requires a large bolus injection of CM to demonstrate the Abdominal aorta and its branches for a survey examination.

• If a more detailed study is needed a selective catheterization of one of the branches is performed by inserting a catheter into a vessel of interest.

• Most common selective study are celiac and renal.


Pt. position:• Pt is imaged supine and lies in AP position.

• Central ray at the level of L2.

• Careful centring to include the proximal and distal ends of pathology on radiograph.

• Representative injection and imaging program are 25 ml/sec for a 60-ml total volume of contrast medium and two images per second for 4 seconds followed by one image per second for 4 seconds in each plane.

• Biplane radiography is preferred.


• Whole of the abdominal aorta should be visualized from the diaphragm to the aortic bifurcation.

The AP projection best demonstrates the renal artery origins, the aortic bifurcation, and the course and general condition of all abdominal visceral branches.

The lateral projection best demonstrates the origins of the celiac and superior mesenteric arteries because these vessels arise from the anterior abdominal aorta.


Role of technologist

The CIT performs the following steps:• Begin imaging simultaneously with injection of the contrast

material.• Make exposures in each plane at rates ranging from one and

one-half to three exposures per second for 3 to 4 seconds; exposures may then slow to one image or less per second for an additional 3 to 5 seconds.

• Make the exposures at the end of suspended inspiration.


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Radiation Protection

• All the available equipments of radiation protection should be implemented. Eg, lead apron, thyroid shield, lead gloves and lead goggles etc.

• Beam restriction

• Avoidance of repeat exposure


Complications

Angiographic procedures are not risk free. Some of the most common risks and complications include the

following:•Bleeding at the puncture site: this usually can be controlled by

applying compression•Thrombus formation: a blood clot may form in a vessel and disrupt the

flow to distal parts•Embolus formation: a piece of plaque may be dislodged from a vessel

wall by the catheter. A stroke or other vessel occlusion may result•Dissection of a vessel: the catheter may tear the intima of a vessel•Infection of puncture site: this is caused by contamination of the

sterile field•Contrast media reaction: this may be mild, moderate, or severe


Other selective arteriograms

• Celiac: Splenic:



Fig: superior mesentric arteriography Inferior mesentric arteriography


Fig: renal arteriography

Pulmonary arteriography


Rt sided early phaseLt sided

References:

• Merrill’s atlas of radiographic positions and radiologic procedures, 12th ed.

• Clark k.c., special procedures in radiography.• Sparks et.al, imaging of abdominal aortic aneurysm• Tutorial ppts.• Various other websites.


aortography

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