Posts tagged ‘disease’

June 13, 2014

Vascular Series Part 3 – MRA

MRAAs part of our continuing series on vascular health and imaging, we’d like to talk about another way of seeing into your body and imaging blood vessels: MR angiography, or magnetic resonance angiography.

 

MR angiography is different than CT angiography in that it uses MRI or magnetic resonance imaging with no radiation. This is a benefit of MR angiography.  MR angiography may or may not require use of an IV injection. When needed, MR angiography uses a different type of contrast material for injection – gadolinium-based instead of iodine-based. This is particularly helpful for people with iodine-contrast allergies or poor kidney function.

 

MR angiography can be used to image the blood vessels and blood flow. The procedure can produce some truly beautiful pictures of blood vessels (the physics behind creating those images is fascinating – and complex!). The vessel walls and adjacent tissues can be seen, as opposed to traditional angiography which shows only the vessel lumen or the inside of the vessel. CTA is the best tool for showing the walls of the vessels themselves.

 

So, what do we use MRA for?

 

We can use it to evaluate almost any artery or vein in the body. For example, MR angiography of the head (usually done without contrast) is helpful when looking for aneurysms (saclike outpouchings arising from blood vessels which can be deadly or disabling if they bleed) or areas of artery narrowing. To evaluate the abdominal aorta, we can look for aneurysms (abnormal dilatation) or dissection (when there is a tear in the vessel creating two channels). We may be asked to evaluate the renal arteries for narrowings- renal artery stenosis is one of the treatable causes of high blood pressure.  MR angiography can also be used to examine the leg arteries when needing to evaluate for causes of pain when walking.

As we have discussed, there are lots of ways of imaging the blood vessels. Often, ultrasound with Doppler is used first to see if there is a need for further investigation. CT angiography or MR angiography can further define the vessels and identify problems that may need to be addressed either surgically or with interventional radiology procedures (angioplasty, stenting). Traditional catheter angiography is often reserved for those cases that will benefit from vascular intervention.

Diagnostic Imaging Centers blogs on regularly about women’s health atwww.mammographykc.com and general radiology atwww.diagnosticimagingcenterskc.com. Visit our sites for more helpful information!

 

June 11, 2014

Vascular Series Part 2 – What Is CT Angiography (CTA)?

CTACT angiography, or computed tomography angiography, (now you see why we like to call it CT angiography- such a mouthful!) is a way of imaging the blood vessels and surrounding tissues.

 

Why would we do that? CT angiography is a noninvasive way to exquisitely evaluate blood vessels within the body. With a simple venous injection of contrast we can quickly and elaborately evaluate the artery, the wall of the artery and the surrounding tissues.  Let’s look at an example. Say we need to evaluate patients with suspected narrowing in the neck arteries – CT angiography may follow an abnormal carotid Doppler to confirm how narrow the vessel is and to see if surgery will be necessary. It will show calcifications and noncalcified plaques and show how they affect the lumen (inside of the vessel) of the artery. This test is helpful in planning any necessary surgeries.

 

CT angiography can also be used to look at the arteries in the head for patients with strokes from bleeds. Aneurysms  (focal outpouchings) and their relation to the vessel are well seen and this procedure can help plan interventions needed to address them.

 

So now we know why we need to perform CT angiography, it begs the question, why is this modality of imaging the best choice for a situation? In the past, catheter angiography was the traditional way of imaging blood vessels of all types. However, it involves  putting a catheter through the skin into vessels, usually with an approach through the groin or in the arm. This creates beautiful images of the insides of the vessels, but is associated with some risks related to the catheter and the arterial puncture.

 

CT allows us to get exquisite images of the vessels with an injection into a vein in a less risky fashion while also allowing us to see the blood vessel wall – not just the lumen as is seen in traditional angiography. CT angiography can be used to evaluate blood vessels from the head to the toes and most parts in between.

In some cases, CT angiography has replaced or nearly replaced the need for catheter angiography (CT angiography chest to evaluate for pulmonary emboli or blood clots in the vessels in the lungs is one example). Other times, CT angiography will identify those patients that will benefit from catheter angiography – often this is used when interventions like angioplasty (ballooning narrowed areas in the arteries) or stenting (putting in metal or mesh stents to open up narrowings) are needed.

 

All told, CT angiography may be a lot of syllables but it can save a lot of lives.

Diagnostic Imaging Centers blogs on regularly about women’s health atwww.mammographykc.com and general radiology atwww.diagnosticimagingcenterskc.com. Visit our sites for more helpful information!

 

June 6, 2014

Vascular Series Part 1 – Carotid Doppler Screening

Carotid ultrasound by National Heart Lung and Blood Insitute (NIH) via Wikimedia Commons Copyright Public DomainEveryone’s heard of cardiovascular disease, which is the leading killer of men and women in our country, but for many the term brings to mind only heart disease.

 

Being heart-health focused is great! But having healthy arteries is also critical to health and longevity. There are 795,000 US citizens affected by stroke each year. Strokes can be caused by blockage of blood flow in the vessels leading to or in the brain or bleeding from vessels in the brain.

 

Both cause death of cells in the brain if not treated promptly. Death of neurons can result in significant disabilities or death. Risks for the development of strokes include age, smoking, high cholesterol, diabetes, high blood pressure, family history, as well as heart conditions including atrial fibrillation, inactivity, obesity (just to name a few). One of the best things a person can do to fight this disease is to stay active!

 

Thickening of the arteries which go to the brain (atherosclerosis) can lead to strokes. Blood flow can become blocked by clot, or plaques lining the arteries can break off and travel to the smaller vessels in the brain causing blockages.

 

One noninvasive way of looking at these conditions of the carotid arteries in the neck is with Doppler.  This is an ultrasound technique which can show blood flow in vessels. Narrowing of vessels causes an increase in the velocity of flow through them (much the same as increasing the rate of flow through your garden hose by holding your thumb over and narrowing the opening).

 

Doppler will look at the velocities in the arteries in the neck allowing us to find areas of narrowing. Doppler can estimate the degree of narrowing by looking at the velocities. Ultrasound of the arteries also allows us to see the wall and plaques causing the narrowing.

 

Carotid Doppler can be indicated to evaluate patients with mini-stroke symptoms or those at high risk for strokes. Sometimes carotid Doppler is indicated in high risk patients who are undergoing surgery for preoperative assessment of stroke risk.

 

If you’d like to know more about how to stay (or get!) heart and vessel healthy, we recommend the American Heart Association’s website.

(Image credit: Carotid ultrasound by National Heart Lung and Blood Institute (NIH) via Wikimedia Commons Copyright Public Domain)

Diagnostic Imaging Centers blogs on regularly about women’s health atwww.mammographykc.com and general radiology atwww.diagnosticimagingcenterskc.com. Visit our sites for more helpful information!

 

February 11, 2014

Heart Health: CT Coronary Calcium Score

One image from a coronary calcium  score showing calcifications (which show up as bright white, like the bones) in the wall of the coronary arteries at a level just above the heart.

One image from a coronary calcium score showing calcifications (which show up as bright white, like the bones) in the wall of the coronary arteries at a level just above the heart.

It’s heart month! We are joining with the American Heart Association in trying to raise awareness of the leading killer of women and men. In the past, we’ve explained the basics of a CT scan,  and today we’d like to talk about a specific use of the technology to obtain a CT Coronary Calcium Score.

A Coronary Calcium Score is a scan of the heart which evaluates the arteries for the presence of calcium. Calcium build up in the arteries is one part of coronary atherosclerosis – the process by which arteries are narrowed by buildup of plaque, both calcified and noncalcified (soft). Finding calcium in the arteries of the heart indicates coronary artery disease and is associated with an increased risk of future cardiovascular events, like heart attacks.

Obtaining a calcium score is a simple, quick, painless procedure. You will have EKG leads placed and then a quick scan of the heart will be done with the CT machine. No contrast is needed. Your study will be reviewed by your radiologist with computer assisted analysis. All calcium related to the coronary (heart) arteries will be identified, and a summation of the amount of calcium present will be reported. The score will be compared with others of the same age and sex.

The calcium score will give an estimate of the likelihood of significant coronary artery disease. It is important to remember that not all coronary artery disease will be calcified. Soft areas of plaque will not be found by this technique.

Coronary calcium score is a useful tool to consider for anyone in an intermediate risk category for heart disease or in some low-risk patients, especially those with a family history of early heart disease (before the age of 55 in a man or 65 in a woman).

What places someone in an intermediate risk category? Things like smoking, a family history of heart disease or high cholesterol can be factors. To determine your risk for heart disease, the Mayo Clinic has an excellent tool, found here. In intermediate and low risk patients, a calcium score can be an important independent predictor of the risk of future heart problems.

Recently, the American College of Radiology has reviewed the recommendations to determine the relative importance of getting a calcium score for different risk category patients. Their thorough statement and review can be found here.

For all, remember that cardiovascular disease is a leading killer. Take action to find out your risks and ways you can improve your heart health.

February 6, 2014

What is cirrhosis of the liver? – with Dr. Angela Noto