Technology and Industry: Cardiovascular disease in women

If they were asked to name their greatest health fear, most women would probably respond “breast cancer.” But the truth is that nearly 10 times as many women will die from cardiovascular disease (CVD) than from breast cancer. ¹ Traditionally thought of as a “man's disease,” CVD is now the leading killer of American women. In fact, in every year since 1984, deaths from CVD in women have outpaced those in men, with women accounting for nearly 53% of such deaths. ¹

The numbers are sobering. In 2004,  >459,000 women died of CVD. ¹ Approximately 1 of every 3 American women has some form of CVD, with millions more at risk due to hypertension, high cholesterol, obesity, diabetes, smoking, and other factors. ¹ For many women, a fatal myocardial infarction (MI) is the first symptom. ¹

To ensure the best possible outcome following an acute MI, a rapid and accurate diagnosis is essential; however, many women who experience a heart attack may not exhibit the classic symptoms. According to the National Institutes of Health, although approximately two thirds of women experience the typical chest discomfort during acute MI, women tend to report a wider range of symptoms, including: “pain in the middle or upper back, neck, or jaw; shortness of breath; nausea or vomiting; indigestion; loss of appetite; weakness or fatigue; cough; dizziness; and palpitations.” ²

Once women have a heart attack, their outcomes tend to be worse than those for men as well: approximately 43% of women aged 40 years who have an acute MI will die within 5 years, compared with only 18% of men in similar circumstances. ¹

Just as it is for men, it is essential that women understand the risks for CVD, address those that they can (eg, maintain a healthy body weight, avoid smoking, etc), and undergo appropriate testing when necessary. Often that testing may include computed tomography (CT) scanning. Toshiba America Medical Systems (Tustin, CA) recently introduced a new multidetector CT system with several features designed specifically for cardiac imaging.

The Aquilion ONE

“The Aquilion ONE has the ability to cover 4 times the distance of a typical CT scanner,” said Douglas Ryan, Senior Director of the CT Business Unit at Toshiba. “Today’s state-of-the-art technology is thought to be 64-slice CT that typically covers 3 to 4 cm of anatomy in a single rotation. In 1 rotation, the Aquilion ONE can cover 16 cm of anatomy, which is almost the entire heart or the entire brain in just 1 rotation.”

“The scanner has 320 detector rows and a 0.35-second rotation speed, which gives us enough temporal resolution to scan the heart,” he continued. This results in a faster scan time and a shorter breath-hold for the patient. “When you scan the heart with a 64-slice scanner, you have a 8- to 10-second acquisition time. With Aquilion ONE’s very large detector, you can actually acquire the heart in 4.35 seconds,” Ryan said.

“The other benefit of going to a larger detector is that you get a much lower radiation dose, by a factor of up to 80%,” he said. “When you scan with a conventional CT system with a smaller detector, you go down through the heart gradually and you have to overlap as the detector is rotating through the body. With Aquilion ONE, we don’t do that overlap; therefore, we eliminate a lot of the extraneous radiation dose in the standard scan.”

“That is so important,” Ryan explained, “because if we can get a very low radiation dose, we can start to look at the heart in more people, from a more generalized population point of view. Of course, you still need some risk factors before you undergo any examination, but it does allow us to treat a broader range of patients if we can lower the radiation dose.”

Cardiac features

The Aquilion ONE has several features that are designed specifically for use in cardiac imaging. The phaseXact component was designed to select the optimal phase within the cardiac cycle to use for reconstruction of the images. Rather than having the user reconstruct an entire series of images at different phases within the cardiac cycle, this feature automatically locates the most quiescent period during that heartbeat and reconstructs an image of the heart at that point. “So it basically automates the workflow by a factor of about 10 times,” said Ryan.

The system also features coronary plaque characterization software known as ^SURE Plaque (Figure 1). This software color codes the vessel walls as well as the calcified and noncalcified plaque. “ ^SURE Plaque looks at the coronary arteries, and, based on the density of the plaque, it color codes it so that the user can see the total plaque burden that a patient has within the coronary arteries,” said Ryan.

The Aquilion ONE also has a Variable Helical Pitch (vHP) feature that allows the physician to complete an examination on >1 anatomic region without stopping to adjust the helical pitch (Figure 2). “When you are scanning different parts of the body, you use different parameters to acquire the images. So rather than do two completely different scans, for which you might have to do two separate contrast injections, vHP allows you to combine different scanning parameters at different speeds all in one examination plan,” explained Ryan. In the case of cardiac imaging, for example, this feature allows the user to scan for both heart disease and an aortic aneurysm in a single examination.

Conclusion

“With the Aquilion ONE, we are changing clinical pathways,” concluded Ryan. “From a radiologist's point of view, it’s really about workflow. By automating all these technologies like phaseXact and vHP, we allow them to scan more patients in a day, but we also increase their diagnostic confidence because they are producing the best images they can.”

He added, “it’s very important that patients are getting the lowest radiation dose possible. Given the concern with women’s health in the United States, this has been a very important milestone.”

REFERENCES

1. American Heart Association. Women and cardiovascular diseases Statistics. Available online athttp://www.americanheart.org/downloadable/heart/1199816973854FS10WM08.pdf. Accessed August 27, 2008.
2. National Institutes of Health. Research matters: Heart attack symptoms in women. Available online at http://www.nih.gov/news/research_matters/december2007/12172007heartat-tack.htm. Accessed August 29, 2008.