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CHICAGO November 29 2011—Findings on coronary CT angiography (CTA), a noninvasive test to assess the coronary arteries for blockages, show different risk scenarios for men and women, according to a study presented today at the Radiological Society of North America (RSNA).

Coronary artery disease (CAD) is a narrowing of the blood vessels that supply blood and oxygen to the heart. It is caused by a build-up of fat and other substances that form plaque on vessel walls. According to the Centers for Disease Control and Prevention, heart disease is the leading cause of death for both men and women in the U.S.

Researchers at the Medical University of South Carolina analyzed the results of coronary CTA on 480 patients, mean age 55, with acute chest pain. Approximately 65 percent of the patients were women, and 35 percent were men. The possibility of acute coronary syndrome was ruled out for each of the patients.

Using coronary CTA, the researchers were able to determine the number of vessel segments with plaque, the severity of the blockage and the composition of the plaque.

“The latest CT scanners are able to produce images that allow us to determine whether the plaque is calcified, non-calcified or mixed,” said John W. Nance Jr., M.D., currently a radiology resident at Johns Hopkins Hospital in Baltimore, Md.

By comparing the coronary CTA results with outcome data over a 12.8-month follow-up period, the researchers were able to correlate the extent, severity and type of plaque build-up with the occurrence of major adverse cardiac events, such as a heart attack or coronary bypass surgery. The statistical analysis tested all plaques combined (calcified, non-calcified and mixed) and each individual plaque type separately.

“We found that the risks for cardiovascular events associated with plaque were significantly different between women and men,” Dr. Nance said.

Within the follow-up period, 70 of the patients experienced major adverse cardiac events, such as death, heart attack, unstable angina or revascularization. In total, 87 major adverse cardiac events occurred among the patients during the follow-up period.

When the outcome data were correlated with the CTA combined plaque findings, the results indicated that women with a large amount of plaque build-up and extensive atherosclerosis are at significantly greater cardiovascular risk than men.

Specifically, the risk for major adverse cardiac events was significantly higher in women than in men when extensive plaque of any kind was present or when more than four artery segments were narrowed.

“This research tells us that extensive coronary plaque is more worrisome in women than the equivalent amount in men,” Dr. Nance said.

However, when analyzing risk factors associated with the presence of individual types of plaque, the risk for major adverse cardiac events was greater in men, compared to women, when their artery segments contained non-calcified plaque.

Dr. Nance said the new data suggested that the atherosclerotic process, or hardening of the arteries, is not necessarily linear and that more research is needed to better understand the disease.

“Our research confirms that coronary CTA provides excellent prognostic information that helps identify risk, but there are gender differences that need to be considered,” Dr. Nance said.

Coauthors are U. Joseph Schoepf, M.D., Christopher Schlett, M.D., Garrett Rowe, B.S., J. Michael Barraza, B.S., and Fabian Bamberg, M.D., M.P.H.

RSNA Editor’s Note: The data in these releases may differ from those in the printed abstract and those actually presented at the meeting, as researchers continue to update their data right up until the meeting.

The analysis of 180 CT angiography studies done using a 320 detector row CT scanner found that a contrast media protocol based on 60 milliliters of iopamidol “had sufficient enhancement in more than 96% of coronary segments,” said Frank Rybicki, MD, of Brigham and Women’s Hospital in Boston, and one of the authors of the study.

“Many centers currently use a higher iodine load comparable or equal to 80 milliliters of iopamidol,” he said. The study shows that “this is not necessary, and the extra contrast means unnecessary costs and increased risk of contrast-induced nephropathy (CIN) to the patients.” The risk of CIN is of special concern for these patients because they commonly have a renal insufficiency, which is known major risk factor for CIN, Dr. Rybicki added.

“We analyzed larger patients only (those with a body mass index of more than 30) and found that 92% of coronary segments had sufficient enhancement,” said Dr. Rybicki. “These results support the general use of 60 milliliters of iopamidol for CT angiography done on 320 detector row CT scanners,” he said.

The study is published in the October, 2011 American Journal of Roentgenology.

The coronary arteries of Princess Ahmose-Meryet-Amon – as visualised by whole body computerised tomography (CT) scanning – will feature in two presentations at the International Conference of Non-Invasive Cardiovascular Imaging (ICNC) this week in Amsterdam (15-18 May). ICNC is now one of the world’s major scientific event in nuclear cardiology and cardiac CT imaging.

The Egyptian princess Ahmose-Meryet-Amon, who lived in Thebes (Luxor) between 1580 and 1550 BC and who is now known to be first person in human history with diagnosed coronary artery disease, lived on a diet rich in vegetables, fruit and a limited amount of meat from domesticated (but not fattened) animals. Wheat and barley were grown along the banks of the Nile, making bread and beer the dietary staples of this period of ancient Egypt. Tobacco and trans-fats were unknown, and lifestyle was likely to have been active.

The coronary arteries of Princess Ahmose-Meryet-Amon – as visualised by whole body computerised tomography (CT) scanning – will feature in two presentations at the International Conference of Non-Invasive Cardiovascular Imaging (ICNC) currently taking place in Amsterdam (15-18 May). ICNC is now one of the world’s major scientific event in nuclear cardiology and cardiac CT imaging.

Both presentations will be based on findings from the Horus study, in which arterial atherosclerosis was investigated in 52 ancient Egyptian mummies. Results have shown that recognisable arteries were present in 44 of the mummies, with an identifiable heart present in 16. Arterial calcification (as a marker of atherosclerosis) was evident at a variety of sites in almost half the mummies scanned, prompting the investigators to note that the condition was common in this group of middle aged or older ancient Egyptians; the 20 mummies with definite atherosclerosis were older (mean 45.years) than those with intact vascular tissue but no atherosclerosis (34.5 years).

Although relatively common at other vascular sites, atherosclerosis in the coronary arteries was evident in only three of the mummies investigated, but was clearly visualised in Princess Ahmose-Meryet-Amon (in whom calcification was present in every vascular bed visualised).

The CT scan image below shows that the princess, who died in her 40s, had atherosclerosis in two of her three main coronary arteries. “Today,” said Dr Gregory S Thomas, director of Nuclear Cardiology Education at the University of California, Irvine, USA, and co-principal investigator of the Horus study, “she would have needed by-pass surgery.”

“Overall, it was striking how much atherosclerosis we found,” said Dr Thomas. “We think of atherosclerosis as a disease of modern lifestyle, but it’s clear that it also existed 3500 years ago. Our findings certainly call into question the perception of atherosclerosis as a modern disease.”

If, however, the princess enjoyed a diet deemed to be healthy and pursued a lifestyle probably active, how could this “disease of modern life” affect her so visibly? Dr Thomas and his co-principal investigator Dr Adel Allam of Al Azhar University, Cairo, suggest three possibilities.

First, that there is still some unknown risk factor for cardiovascular disease, or at least a missing link in our understanding of it. Dr Allam noted a likely effect of genetic inheritance, pointing out that much of the human predisposition to atherosclerosis could be secondary to their genes. He similarly raised the possibility that an inflammatory response to the frequent parasitic infections common to ancient Egyptians might predispose to coronary disease – in much the same way that immunocompromised HIV cases seem also predisposed to early coronary disease. Nor can a dietary effect be excluded, despite what we know of life in ancient Egypt. Princess Ahmose-Meryet-Amon was from a noble family, her father, Seqenenre Tao II, the last pharaoh of the 17th Dynasty.

So it’s likely that her diet was not that of the common Egyptian. As a royal, she would have eaten more luxury foods – more meat, butter and cheese. Moreover, foods were preserved in salt, which may also have had an adverse effect.

Despite the suggestion of a genetic, inflammatory or unknown effect, Drs Thomas and Allam were keen not to discount those risk factors for heart disease which we do know about. Indeed, even in the study’s apparent association of atheroma with increasing age, there was a pattern of prevalence consistent with our own epidemiology today. “Recent studies have shown that by not smoking, having a lower blood pressure and a lower cholesterol level, calcification of our arteries is delayed,” said co-investigator Dr Randall C Thompson of the St Luke’s Mid-America Heart Institute in Kansas City, USA. “On the other hand, from what we can tell from this study, humans are predisposed to atherosclerosis, so it behoves us to take the proper measures necessary to delay it as long as we can.”

Most of the Horus study research was performed at the National Museum of Antiquities in Cairo and would not have been possible without the availability of non-invasive CT scanning, the focus of the ICNC congress in Amsterdam. CT scanning and nuclear medicine imaging are the cornerstones of modern quantifiable cardiac disease detection, with safe and reproducible results.

Recent studies have shown that a 64-detector CT angiography utilizing prospective electrocardiographic (ECG) gating produces a quality image but considerably reduced patient radiation dose when compared to retrospective ECG gating, according to research being presented at the 2011 American Roentgen Ray Society’s annual meeting.

The study was conducted in the Department of Radiology at the University Hospitals Case Medical Center, in Cleveland, OH. Researchers evaluated 29 patients who underwent prospectively-gated 100 kV whole chest CT for preoperative cardiothoracic surgery. The mean radiation dose was determined and compared to a group of regular dose prospectively-gated exams. “The most significant aspect of our study was to demonstrate that pre-operative evaluation of cardiothoracic surgery patients can be reliably and accurately performed with low-dose chest CT that results in a radiation dose reduction of 42% when compared with traditional dose chest CT exams. In an era of heightened awareness of radiation exposure to patients from medical imaging, this is a significant finding,” said Sonali Mehandru, MD, one of the authors of the study.

“In particular, our study showed that low-dose chest CT can provide accurate assessment of the coronary arteries in a sizable percentage of patients. The coronary arteries are particularly important to evaluate prior to cardiothoracic surgery because the presence of coronary artery disease impacts a patient’s risk for perioperative morbidity and mortality,” said Dr. Mehandru.

“Traditionally, this evaluation has been performed with cardiac catheterization — an invasive and expensive procedure. In our study, we found that a large cohort of patients (23 of 38 patients) had accurate enough noninvasive assessment of the coronary arteries on low-dose chest CT that they did not require further evaluation with cardiac catheterization,” she said.

“This is a preliminary study and further research with larger cohorts of patients is needed. However, it is a good starting point in demonstrating that radiation dose from chest CT‘s can be significantly reduced without compromising accuracy or reliability of anatomic evaluation. In preoperative patients who are especially prone to undergoing repeated imaging studies, this radiation dose reduction can be very significant,” said Dr. Mehandru.

Reston, VA (April 28, 2011) — A summary of the National Council on Radiation Protection’s (NCRPs) workshop on the appropriate use of computed tomography (CT) in emergency medicine, and a list of recommendations from participating organizations to help control the inappropriate use of CT in the emergency department, is now available via the May issue of the Journal of the American College of Radiology.

As a generalization, the benefit-risk estimates for CT scanning favor its use over most other imaging procedures and many other types of diagnostic technology. However, concerns have risen regarding the increase in clinical use of CT scans.

“Concerns regarding the clinical use of CT scans prompted the NCRP to host a workshop — with sponsorship from the American College of Radiology (ACR) and the American College of Emergency Physicians (ACEP) and other private and government organizations — to define the circumstances and programs for assessing the value of CT scanning while addressing the issues of utilization patterns, radiation exposures and overutilization,” said Otha Linton, lead author of the summary. Co-authors include Thomas S. Tenforde, PhD, E. Stephen Amis, MD, and Paul Sierzenski, MD.

The workshop presentations and summary form a basis for the preparation of a report that will provide recommendations on a potential path forward to modulate CT use in emergency medicine, trauma and acute health care.

Participating organizations, including the ACR and ACEP, offered the following recommendations:

• Educate health care providers and others of the status and appropriate applications of CT scanning in emergency medicine and acute care.
• Promote processes and skills to reduce the need for CT imaging when possible, such as the use of traditional radiography, ultrasound and emergency point-of-care ultrasound.
• Communicate concerns on the overutilization of CT to hospitals, together with recommended collaborative protocols to reduce variability in CT scanning utilization in emergency medicine.
• Develop mechanisms for reliable recording for emergency medicine patients of the number and doses received in CT scans and other imaging procedures.
• Develop evidence-based guidelines that address the benefits of CT imaging in emergency medicine, including improvements in patient treatments and outcomes.