Posts tagged ‘computed’

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!

 

May 23, 2013

CT: A Better Way to Scan for Lung Cancer

In an article published by the New England Journal of Medicine on May 22nd, the National Lung Screening Trial had good news to report: Through the use of low-dose computed tomography, doctors were able to recognize lung cancer earlier and more often than through traditional chest x-ray.

The initial phases of the study, published in 2011, showed a 20% reduction in mortality among patients diagnosed with lung cancer. This is credited to the fact that twice as many early stage cancers were discovered using low-dose computed tomography (LDCT) than chest x-ray (CXR).

This most recent finding of the study specifically shows that LDCT discovers lung cancers more often than CXR. This is very good news for those at high risk for lung cancer – earlier and improved detection means expediting the process of healing and hopefully recovery.

The American Association for Thoracic Surgery recommends annual LDCT for specific high-risk groups, specifically North Americans meeting any of the following:

  • aged 55 to 79 years old with a history of 30 pack-years* of smoking

  • long-term lung cancer survivors up through the age of 79

  • those with a 20 pack-year history, starting at age 50 if there is an “additional cumulative risk of developing cancer of 5% or greater over the following 5 years.”

Doctor’s note: Please don’t smoke. Avoiding cancer is even better than discovering it early.

648px-X-ray_chest_cancer

Source: X-ray(Chest)Cancer.jpg: unknown
derivative work: Anassagora (talk)
Copyright: Public Domain

*A “pack-year” number is derived from multiplying the number of packs smoked per day times the number of years smoked – so 30 pack years could be smoking 1 pack a day for 30 years, or 2 packs a day for 15 years.