Correlative Imaging & Treatment

List the 3 types of correlative imaging.

• Angiography

• Computed tomography angiography — CTA

• Magnetic resonance angiography — MRA

List the 2 patient situations in which angiography is useful.

• Imaging obese patients

• Post-surgical follow-up

List the 3 things that do not limit angiography.

• Vessel depth

• Bowel gas

• Aberrant vascular anatomy

List the 4 general limitations of angiography.

• Uncomfortable for the patient

• Relatively expensive

• Radiation exposure

• Invasive

Why is angiography considered invasive?

Why is angiography considered invasive?

What are the concerns associated with contrast use during angiography?

Contrast may cause an allergic reaction, and the slide lists it as contraindicated in patients with renal failure and shellfish allergies.

What type of imaging is used during angiography?

Radiographic imaging, or X-rays.

Why is contrast injected during angiography?

To highlight the vessels so they can be evaluated for filling defects or lack of contrast filling.

What is digital subtraction angiography, or DSA?

Digitally stored images are manipulated to “subtract” tissue interference.

How is the degree of stenosis calculated with angiography?

Measure the AP dimensions of a normal segment and the abnormal segment.

What can a lack of contrast filling indicate in an artery?

It can indicate:

1. Arterial narrowing

2. Total occlusion

What additional vascular pathways can angiography demonstrate?

Collateral pathways.

What does a lack of filling indicate on venous angiography?

Thrombus

What does retrograde filling indicate on venous angiography?

Venous insufficiency.

How do CTA and MRA compare with conventional arteriography in invasiveness?

CTA and MRA are less invasive than conventional arteriography

List the 3 uses of CTA and MRA

• Patient management

• Surgical planning

• Post-procedure follow-up

What is CTA?

A specialized radiologic procedure that uses contrast to examine blood flow in the arteries.

What type of contrast and imaging energy are used in CTA?

• Contrast is the same as angiography contrast.

• Radiation is used for imaging.

How does CTA create its images?

Sophisticated computer instrumentation obtains images from multiple locations.

What can CTA do with a 2D image?

Convert a 2D image into a 3D image.

What contraindications does CTA

The same contraindications as angiography.

How are MRA images obtained?

Using radio waves in a strong magnetic field

What types of vascular images can MRA produce?

• 2D images

• 3D images

List the 4 metallic-related contraindications for MRA l

• Exposure to metallic objects

• Surgical clips

• Pacemakers

• Metal workers

What concern about gadolinium is mentioned on the MRA slide?

The slide notes that gadolinium stays in the body

What is the overall purpose of vascular treatment?

To manage symptoms and disease

List the 2 main types of vascular treatment.

• Medical treatment

• Surgical treatment

What type of vascular treatment is generally attempted first?

Less-invasive treatments

List the 3 effects of antihypertensive medications.

• Lower blood pressure

• Dilate arteries

• Inhibit hormones that raise blood pressure

List the 3 antihypertensive medications or medication classes

• ACE inhibitors

• Beta blockers

• Diuretics

What does ACE stand for?

Angiotensin-converting enzyme.

What do anticoagulants do?

They slow the blood-clotting process.

What thrombolytic medication is listed

Urokinase

When are thrombolytics used?

On an emergent basis for a specific target.

List the 2 specific thrombolytic situations

• Stroke — TPA

• Impending limb loss

When is heparin used?

As the initial treatment.

What does heparin do to a thrombus?

It prevents extension of the thrombus, but it does not dissolve the thrombus.

When is Warfarin used in relation to heparin therapy?

When is Warfarin used in relation to heparin therapy?

List the 3 additional conditions or situations associated with Warfarin

• Mesenteric disease

• Endograft placement

• Venous thrombosis

List the 6 surgical treatments

• Stent/stent graft

• EVAR

• Coil

• Endarterectomy

• Bypass graft

• Transplantation

What is an endarterectomy?

The surgical removal of plaque.

What 3 things are removed during a carotid endarterectomy?

• Intima

• Media

• Plaque

What is an aortic endograft used to treat?

It is a covered stent used for an aneurysm.

What procedure is angioplasty with stent placement also called?

PTA/PTCA. It is used for stenosis and/or stent placement.

What is the purpose of an IVC interruption device, or IVC filter?

It “catches” thromboemboli.

What does TIPS create, and what is its purpose?

TIPS creates a shunt between the portal and hepatic veins to reduce portal hypertension.

What type of graft is an aortic endograft?

A synthetic graft.

What is the purpose of an aortic endograft?

To “bypass” the aneurysm.

List the 2 locations where an aortic endograft may be placed.

• Within the existing aneurysm — most likely

• Adjacent to the aneurysm

List the 2 classic sonographic findings of an aortic endograft.

• Echogenic

• “Ribbed” walls

List the 6 complications of an aortic endograft.

• Hematoma

• Infection

• Rupture

• Stenosis

• Pseudoaneurysm

• Endoleak

What is an endoleak?

Blood flow “escapes” and continues to fill the aneurysm sac.

What is a Type 1 endoleak?

A leak at the graft ends — proximal, distal, or iliac occluder.

What is a Type 2 endoleak?

The aneurysm sac fills through an aortic branch vessel.

It is also called a retroleak and may spontaneously resolve.

What is a Type 3 endoleak?

A leak within the graft material caused by mechanical failure.

What is a Type 4 endoleak?

Leakage through a porous graft.

What is a Type 5 endoleak?

Endotension, where the aneurysm sac continues to expand for an idiopathic reason.

What is the preferred follow-up method for an aortic endograft?

CTA.

What are the 2 points listed about using duplex sonography for aortic endograft follow-up?

• It should be performed by experienced sonographers.

• Cine clips are used to document leaks.

List the 2 abnormalities that can be treated with a coil.

• Aneurysms

• A/V fistulas

How does coil treatment work?

A thin wire is used to “fill” or occlude the aneurysm or fistula.

Where is coil treatment performed?

In the angiography suite.

How is access typically obtained for coil treatment?

Through the groin using the Seldinger technique.

What is the purpose of angioplasty?

To dilate vessel segments with a focal atherosclerotic lesion.

What technique is used for angioplasty?

The Seldinger technique.

What type of catheter is used for angioplasty?

A balloon-tipped catheter.

What happens when the balloon is inflated during angioplasty?

The balloon pushes plaque against the vessel wall, dilating the artery and bringing the arterial lumen dimensions closer to normal

What is the main purpose of a stent after balloon angioplasty?

To maintain intraluminal structure and vessel patency.

What does the PowerPoint say about stents and restenosis after balloon angioplasty?

What does the PowerPoint say about stents and restenosis after balloon angioplasty?

List the 4 types of stents

• Balloon-expandable

• Self-expanding

• Thermal-expanding — not widely used

• Covered stents

What is the usual treatment for IVC thrombosis?

Anticoagulation therapy.

What is the purpose of an IVC filter in IVC thrombosis?

To prevent propagation of thrombus.

What association with pulmonary emboli is listed for IVC filters?

IVC filter use is very common in the presence of pulmonary emboli.

Where is an IVC filter placed?

Distal to the renal veins.

How does an IVC filter appear sonographically?

Highly reflective.

How is median arcuate ligament syndrome surgically treated?

The median arcuate ligament is cut to allow free movement of the celiac artery.

What determines surgical treatment for mesenteric ischemia?

The viability of the bowel.

What happens if the bowel is severely injured from mesenteric ischemia?

The damaged bowel is resected, meaning removed.

What procedure may be performed intraoperatively for mesenteric ischemia?

Thrombectomy.

When may an aortomesenteric bypass be needed?

In an emergency or with widespread atherosclerosis.

List the 2 treatment methods for portal hypertension.

• Medications

• Intervention

List the 5 purposes of medications used for portal hypertension.

• Control bleeding in varices

• Decrease platelet aggregation

• Promote oxygenation to tissues

• Reduce hepatic resistance

• Decrease ascites

What do vasoconstrictors do in portal hypertension?

They restrict flow to the portal system through the splanchnic vessels.

List the 2 vasoconstrictors given

• Vasopressin

• Somatostatin

List the 2 effects of beta blockers listed for portal hypertension.

• Increase oxygenation to tissues

• Decrease platelet aggregation

List the 2 beta blockers

• Propranolol

• Nadolol

What do vasodilators do in portal hypertension?

They decrease resistance in the hepatic parenchyma

What vasodilator medication is listed?

Nitroglycerin/nitrates.

What is the purpose of a diuretic in portal hypertension?

To promote removal of excess fluid through the urinary system.

What diuretic is listed in the PowerPoint?

Lasix

What vascular pathway is created during a TIPS procedure?

A pathway between the right portal vein and right hepatic vein, which is the most common configuration.

List the 2 indications for TIPS given on the slide.

• End-stage cirrhosis

• Management of portal hypertension

What is the contraindication for TIPS given?

Right-sided heart failure.

Where is venous access obtained for a TIPS procedure?

The internal jugular vein is cannulated.

What pathway is followed from the internal jugular vein during TIPS placement?

Through the right atrium → IVC → right hepatic vein.

Between which 2 veins is a tunnel created during a TIPS procedure?

• Right hepatic vein

• Right portal vein

Where is the TIPS anastomosis created?

Between the main portal vein and a selected hepatic vein, usually the right hepatic vein.

What keeps the TIPS shunt open?

A stent.

List the 5 main effects or benefits of a TIPS.

• Controls portal hypertension

• Reduces ascites

• Prevents esophageal-variceal hemorrhage

• Improves quality of life

• Acts as a bridge to transplantation

List the 3 additional conditions or syndromes that TIPS may help manage.

• Budd-Chiari

• Hepatorenal syndrome

• Hepatopulmonary syndrome