Journal of Cardiovascular Computed Tomography

Journal introduction

Allen J. Taylor — 2009-11-26

Change permeates our discussions in health care today. Whether health care reform or the changing reimbursement landscape (in which imaging appears centrally in the discussion), change is everywhere. Although these issues dominate the conversations in the United States, worldwide there is a simultaneous and synergistic revolution in quality and performance within medicine. Cardiovascular imaging has joined in, and great strides are being achieved in, all aspects of cardiovascular CT. As individuals it may be difficult to shape governmental policy, but we can all contribute to quality, if even on a local level. It is hoped that our shared commitment to imaging quality and performance will create opportunities within health care reform and reimbursement. SCCT Advocacy is hard at work ensuring that your voice is heard!

Noncardiac findings on cardiac CT. Part II: Spectrum of imaging findings

Ronan P. Killeen, Ricardo C. Cury, Aoife McErlean, Jonathan D. Dodd — 2009-11-02

Abstract: Cardiac computed tomography (CT) has evolved into an effective imaging technique for the evaluation of coronary artery disease in selected patients. Two distinct advantages over other noninvasive cardiac imaging methods include its ability to directly evaluate the coronary arteries and to provide a unique opportunity to evaluate for alternative diagnoses by assessing the extracardiac structures, such as the lungs and mediastinum, particularly in patients presenting with the chief symptom of acute chest pain. Some centers reconstruct a small field of view (FOV) cropped around the heart but a full FOV (from skin to skin in the area irradiated) is obtainable in the raw data of every scan so that clinically relevant noncardiac findings are identifiable. Debate in the scientific community has centered on the necessity for this large FOV. A review of noncardiac structures provides the opportunity to make alternative diagnoses that may account for the patient's presentation or to detect important but clinically silent problems such as lung cancer. Critics argue that the yield of biopsy-proven cancers is low and that the follow-up of incidental noncardiac findings is expensive, resulting in increased radiation exposure and possibly unnecessary further testing. In this 2-part review we outline the issues surrounding the concept of the noncardiac read, looking for noncardiac findings on cardiac CT. Part I focused on the pros and cons for and against the practice of identifying noncardiac findings on cardiac CT. Part II illustrates the imaging spectrum of cardiac CT appearances of benign and malignant noncardiac pathology.

Automated 3-dimensional quantification of noncalcified and calcified coronary plaque from coronary CT angiography

2009-10-05

Introduction: We aimed to develop an automated algorithm (APQ) for accurate volumetric quantification of non-calcified (NCP) and calcified plaque (CP) from Coronary CT angiography (CCTA).Methods: APQ determines scan-specific attenuation thresholds for lumen, NCP, CP and epicardial fat, and applies knowledge-based segmentation and modeling of coronary arteries, to define NCP and CP components in 3D. We tested APQ in 29 plaques for 24 consecutive scans, acquired with dual-source CT scanner. APQ results were compared to volumes obtained by manual slice-by-slice NCP/CP definition and by interactive adjustment of plaque thresholds (ITA) by 2 independent experts.Results: APQ analysis time was <2 sec per lesion. There was strong correlation between the 2 readers for manual quantification (r = 0.99, p < 0.0001 for NCP; r = 0.85, p < 0.0001 for CP). The mean HU determined by APQ was 419 ± 78 for luminal contrast at mid-lesion, 227 ± 40 for NCP upper threshold, and 511 ± 80 for the CP lower threshold. APQ showed a significantly lower absolute difference (26.7 mm3 vs. 42.1 mm3, p = 0.01), lower bias than ITA (32.6 mm3 vs 64.4 mm3, p = 0.01) for NCP. There was strong correlation between APQ and readers (R = 0.94, p < 0.0001 for NCP volumes; R = 0.88, p < 0.0001, for CP volumes; R = 0.90, p < 0.0001 for NCP and CP composition).Conclusions: We developed a fast automated algorithm for quantification of NCP and CP from CCTA, which is in close agreement with expert manual quantification.

Quantification of coronary atherosclerosis with coronary computed tomography: Impact on clinical risk assessment?

Paul Schoenhagen, Hiroyuki Niinuma — 2009-10-05

Coronary computed tomographic angiography (CTA) is an accepted diagnostic test in defined symptomatic patient populations and allows routine evaluation of the arterial lumen and vessel wall. In symptomatic patients, assessment of coronary anatomy has the immediate goal to exclude hemodynamically significant stenosis (typically defined as angiographic stenosis >50%) but also the longer-term goal to assess risk of future cardiovascular events. On the basis of postmortem studies and other imaging modalities it is well known that the extent of disease, measured by the number of stenotic lesions/vessels, the calcium score, or overall plaque burden, correlates with future events. In addition, certain plaque features are considered high risk (vulnerable plaques, “thin cap fibroatheromata).

Paradigm of pretest risk stratification before coronary computed tomography

2009-11-02

Background: The optimal method of determining the pretest risk of coronary artery disease as a patient selection tool before coronary multidetector computed tomography (MDCT) is unknown.Objective: We investigated the ability of 3 different clinical risk scores to predict the outcome of coronary MDCT.Methods: This was a retrospective study of 551 patients consecutively referred for coronary MDCT on a suspicion of coronary artery disease. Diamond-Forrester, Duke, and Morise risk models were used to predict coronary artery stenosis (>50%) as assessed by coronary MDCT. The models were compared by receiver operating characteristic analysis. The distribution of low-, intermediate-, and high-risk persons, respectively, was established and compared for each of the 3 risk models.Results: Overall, all risk prediction models performed equally well. However, the Duke risk model classified the low-risk patients more correctly than did the other models (P < 0.01). In patients without coronary artery calcification (CAC), the predictive value of the Duke risk model was superior to the other risk models (P < 0.05). Currently available risk prediction models seem to perform better in patients without CAC. Between the risk prediction models, there was a significant discrepancy in the distribution of patients at low, intermediate, or high risk (P < 0.01).Conclusions: The 3 risk prediction models perform equally well, although the Duke risk score may have advantages in subsets of patients. The choice of risk prediction model affects the referral pattern to MDCT.

Clinical prediction of obstructive coronary disease in patients referred for coronary CTA: “Low-hanging fruit” or still a “risky business”?

Aiden Abidov — 2009-11-16

The data supporting abdominal ultrasound scanning as a screening tool for the abdominal aortic aneurysm provides a roadmap that defines a successful cardiovascular imaging procedure. The procedure begins with patient selection characteristics (age, sex, and a history of smoking), is followed by quality imaging, and leads to survival benefit. Although focus tends to often be directed at the imaging “centerpiece,” the optimal selection of the target population most likely to benefit from the imaging procedure is a crucial first step in the process. Without defining the correct population for testing, any hope of optimizing cardiovascular outcomes is lost.

Coronary artery calcium scoring using a reduced tube voltage and radiation dose protocol with dual-source computed tomography

2009-10-15

Background: Technical advances to minimize radiation exposure because of imaging are in accord with the “as low as reasonably achievable” principle.Objective: We aimed to determine whether coronary calcium scoring (CCS) by multidetector CT at a tube voltage of 100 kVp yields comparable results to the standard 120-kVp protocol while reducing radiation dose.Methods: Sixty consecutive outpatients were scanned with a dual-source CT scanner with both the120- and 100-kVp protocols. The calcium threshold was 130 Hounsfield units (HUs) for 120 kVp and 147 HU for 100 kVp, as determined from phantom data. All 100-kVp scans were scored by an experienced reader blinded to 120-kVp data.Results: Image quality was comparable for 100- and 120- kVp scans. Mean Agatston scores for 100 and 120 kVp were 189 ± 484 and 189 ± 498 (P = 0.92), with perfect correlation (r = 1.0; P < 0.0001; 95% limits of agreement, -36 to 37; bias, 0.6). Mean coronary calcium volume scores for 100 and 120 kVp were 143 ± 370 mm3 and 149 ± 392 mm3 (P = 0.26), with perfect correlation (r = 1.0; P < 0.0001; 95% limits of agreement, -35 to 32 mm3; bias, -1.4 mm3). The mean absolute difference for Agatston scores between the protocols was 16.9, with excellent agreement (κ = 0.95; P < 0.0001). Mean effective radiation dose for the 100-kVp protocol was significantly lower (1.17 mSv versus 1.70 mSv; P < 0.0001).Conclusion: A reduced tube current protocol using 100 kVp gives equivalent CCS results at reduced radiation exposure compared with a standard protocol at 120 kVp.

Coronary calcium scoring at 100kVp: A new twist to a familiar test

Juan J. Rivera, Arthur S. Agatston — 2009-10-15

The search for alternatives to identify heightened risk from atherosclerosis and its clinical consequences arises from the reality that coronary heart disease accounts for approximately two-thirds of all fatalities in the United States. Recognizing this, in the late 1980s David King, Dr. Arthur Agatston, and Dr. Warren Janowitz applied the first electron beam computed tomography (CT) scanner to identify the presence of calcified atherosclerosis in the coronary arteries. King, the director of clinical science with what was then the Imatron Corporation, recognized the higher sensitivity of electron beam CT compared with fluoroscopy to identify coronary arterial calcification (CAC). Agatston, director then of the noninvasive cardiovascular laboratory at Mount Sinai Hospital in Miami Beach, Florida, immediately saw the potential role for more precise quantification of coronary calcium. Their seminal findings, the ability to accurately detect the presence of CAC based on autopsy studies and its correlation with atherosclerosis burden, established the field of CT-based detection of atherosclerosis and set the stage for what has been 2 decades of productive research and development on its clinical application.

What are the basic concepts of temporal, contrast, and spatial resolution in cardiac CT?

Eugene Lin, Adam Alessio — 2009-08-03

Abstract: An imaging instrument can be characterized by its spatial resolution, contrast resolution, and temporal resolution. The capabilities of computed tomography (CT) relative to other cardiac imaging modalities can be understood in these terms. The purpose of this review is to characterize the spatial, contrast, and temporal resolutions of cardiac CT in practical terms.

Evaluation of myocarditis with delayed-enhancement computed tomography

Kelly Axsom, Fay Lin, Jonathan W. Weinsaft, James K. Min — 2009-09-25

Abstract: A healthy 19-year-old man with no history of substance abuse presented with 3 days of dyspnea and chest pressure relieved by leaning forward associated with nausea, emesis, and diarrhea. Cardiac computed tomography angiography (CCTA) showed normal coronary artery anatomy and no evidence of coronary artery plaque. The delayed-enhancement CCTA showed patchy epicardial and mid-myocardial enhancement of the wall and apex, consistent with myocardial inflammation. Delayed-enhancement cardiac magnetic resonance imaging (CMR) performed the following day confirmed patchy, diffuse epicardial hyperenhancement of the lateral wall, septum, and apex consistent with myocardial inflammation. Both CCTA and CMR supported the diagnosis of acute myocarditis. Delayed-enhancement CCTA is correlated with delayed-enhancement CMR in acute myocarditis by territory and extent and can show late hyperenhancement that can be transmural, subepicardial, or confined to small foci within a layer of the myocardium. Delayed-enhancement CCTA has potential utility for simultaneous evaluation of coronary arteries and myocardial inflammation in suspected myocarditis.

Persistent fifth aortic arch in a patient with a history of intrauterine thalidomide exposure

Seth Kligerman, Andre Blum, Suhny Abbara — 2009-08-03

Abstract: Persistence of the fifth aortic arch is a very rare congenital anomaly often associated with various other congenital cardiac and aortic abnormalities. It is important to be aware of this anomaly and not confuse it with other aortic pathology.

Use of electrocardiographic-gated 4-dimensional CT to assess patency of abdominal aortic branch vessels in type B dissection

Michael A. Bolen, Tara M. Mastracci, Paul Schoenhagen — 2009-10-15

Abstract: CT plays an important role in the evaluation of suspected aortic dissection. In this case, use of ECG gating and 4D imaging demonstrated of dynamically changing perfusion to an abdominal aortic visceral branch vessel in a type B dissection.

Complete left pericardial defect: Evaluation with supine and decubitus dual source CT

2009-08-03

Abstract: We present a case of complete left pericardial defect which was evaluated with retrospectively gated dual source CT. Imaging findings included right heart chamber dilatation, extreme levoposition and excessive cardiac mobility which was demonstrated by repeat imaging in the left lateral decubitus position. Cardiac CT is an excellent means of evaluating pericardial disease owing to its high spatial resolution. Decubitus imaging helps confidently distinguish partial from complete forms of pericardial defect.

Society News

2009-11-05

President's page: The way ahead

Jack Ziffer — 2009-11-16

Although frequently misquoted, the philosopher and writer George Santayana commented in The Life of Reason, “Those who cannot remember the past are condemned to repeat it.” Before embarking on a journey into our future, a very brief recognition of two individuals who shaped our history is particularly relevant this year, for it marks the last year that “The Way Ahead” lecture and column in this journal will be unnamed.

Author Index to Volume 3

2009-11-01

Keyword Index to Volume 3

2009-11-01