Daniel W. Entrikin

CT Angiography for Safe Discharge of Patients with Possible Acute Coronary Syndromes

BACKGROUND Admission rates among patients presenting to emergency departments with possible acute coronary syndromes are high, although for most of these patients, the symptoms are ultimately found not to have a cardiac cause. Coronary computed tomographic angiography (CCTA) has a very high negative predictive value for the detection of coronary disease, but its usefulness in determining whether discharge of patients from the emergency department is safe is not well established. METHODS We randomly assigned low-to-intermediate-risk patients presenting with possible acute coronary syndromes, in a 2:1 ratio, to undergo CCTA or to receive traditional care. Patients were enrolled at five centers in the United States. Patients older than 30 years of age with a Thrombolysis in Myocardial Infarction risk score of 0 to 2 and signs or symptoms warranting admission or testing were eligible. The primary outcome was safety, assessed in the subgroup of patients with a negative CCTA examination, with safety defined as the absence of myocardial infarction and cardiac death during the first 30 days after presentation. RESULTS We enrolled 1370 subjects: 908 in the CCTA group and 462 in the group receiving traditional care. The baseline characteristics were similar in the two groups. Of 640 patients with a negative CCTA examination, none died or had a myocardial infarction within 30 days (0%; 95% confidence interval [CI], 0 to 0.57). As compared with patients receiving traditional care, patients in the CCTA group had a higher rate of discharge from the emergency department (49.6% vs. 22.7%; difference, 26.8 percentage points; 95% CI, 21.4 to 32.2), a shorter length of stay (median, 18.0 hours vs. 24.8 hours; P<0.001), and a higher rate of detection of coronary disease (9.0% vs. 3.5%; difference, 5.6 percentage points; 95% CI, 0 to 11.2). There was one serious adverse event in each group. CONCLUSIONS A CCTA-based strategy for low-to-intermediate-risk patients presenting with a possible acute coronary syndrome appears to allow the safe, expedited discharge from the emergency department of many patients who would otherwise be admitted. (Funded by the Commonwealth of Pennsylvania Department of Health and the American College of Radiology Imaging Network Foundation; ClinicalTrials.gov number, NCT00933400.).

Imaging of infective endocarditis with cardiac CT angiography

Infective endocarditis (IE) is a disease characterized by high rates of morbidity and mortality that can present with a spectrum of clinical and imaging findings. Cardiac-gated computed tomographic angiography (CTA) has been shown to be highly accurate in evaluation of both coronary artery disease and structural heart disease and is now considered an appropriate preoperative imaging modality in patients undergoing noncoronary cardiac surgery. This review discusses the use of cardiac-gated CTA in preoperative evaluation of patients with IE, with emphasis on imaging findings of valvular and perivalvular complications. Topics include technique tips specific to valve imaging with cardiac-gated CTA, potential benefits of cardiac-gated CTA compared with other imaging modalities such as echocardiography, limitations of imaging patients with IE with cardiac-gated CTA, and an overview of potential findings in patients with IE, including vegetations, valve perforations, perivalvular abscesses, perivalvular pseudoaneurysms, and fistulas. Throughout this review, cardiac-gated CTA findings of IE are presented with echocardiographic and operative correlation to emphasize that cardiac-gated CTA may in select cases provide incremental benefit in the preoperative assessment of patients with IE.

Optimization of radiation dose reduction in cardiac computed tomographic angiography.

Cardiac computed tomographic angiography (CCTA) has evolved at an unprecedented pace over the past decade, during which time it has proven to be an accurate and effective tool for imaging of the heart in a growing list of clinical applications. However, the rapid growth in the use of CT imaging in general has prompted appropriate concerns regarding increasing medical radiation exposure to patients, particularly with regard to potential long-term risks of radiation-induced malignancy on both individual and population levels. As with all medical imaging modalities, imaging the heart with CCTA should be performed in a manner that achieves diagnostic image quality while maintaining patient radiation exposure as low as reasonably achievable (As Low As Reasonably Achievable [ALARA] principle). The goal of this article is to provide the reader with a wide-ranging review of both primary and secondary techniques that are currently available to minimize patient radiation exposure. Some of the techniques described in this article are universal, whereas others may be scanner specific. By gaining a thorough understanding of the various tools and methodologies employed for reduction of radiation exposure, the cardiac imager should be able to formulate CCTA protocols appropriate for their equipment and their clinical applications, in a manner that optimally preserves diagnostic image quality and minimizes patient radiation dose.

Compressive Sensing–based Interior Tomography: Preliminary Clinical Application

Abstract Compressive sensing (CS)-based interior tomography is a state-of-the-art method for accurate image reconstruction from only locally truncated projections. Here, we report our preliminary interior tomography results reconstructed from raw projections of a patient acquired on a GE Discovery CT750 HD scanner. This is the first clinical application of the CS-based interior reconstruction techniques, and the results show an excellent match with those reconstructed from global projections.

Implications of 25% to 50% coronary stenosis with cardiac computed tomographic angiography in ED patients

OBJECTIVE The aim of this study was to determine if patients presenting with symptoms of acute coronary syndrome and found to have 25% to 50% diameter reduction with coronary computed tomographic angiography (CCTA) are likely to benefit from further diagnostic testing. METHODS A registry study of 213 subjects (median age, 51 years; 53% women) with symptoms concerning for possible acute coronary syndrome with low-risk features found to have 25% to 50% maximal diameter stenosis on CCTA was performed at 2 academic medical centers. The analysis was approved by an institutional review board and was conducted with waiver of consent. The potential contribution of additional testing was determined by measuring the major adverse cardiac events (MACEs) from presentation through 30 days. The MACEs included myocardial infarction, coronary revascularization, unstable angina, and cardiovascular death. Sample size calculations were predicated on a 0% MACE rate leading to upper bounds of a 2-sided exact 95% confidence interval less than 2%. RESULTS Thrombolysis in myocardial infarction risk score of less than 2 was present in 92% subjects, 70% (150 of 213) had 2 or more serial cardiac markers performed, and 40% (87 of 213) had stress testing or cardiac catheterization. The MACEs occurred in 1 (0.5%) of 213 subjects (95% confidence interval, 0%-2.6%) and was identified by an elevation of serial cardiac markers during the index hospitalization. No patients experienced cardiovascular death or required revascularization. CONCLUSIONS In patients with emergent low-risk chest pain and 25% to 50% diameter coronary stenosis by CCTA, the rate of near-term MACE is very low. Serial cardiac markers may be beneficial in this subgroup. Routine provocative testing is unlikely to be beneficial during the index visit.

Blood pool inversion volume-rendering technique for visualization of the aortic valve

This brief review focuses on use of an advanced postprocessing volume-rendering technique for cardiac computed tomographic angiography (CTA) called blood pool inversion (BPI). In particular, we focus on the application of BPI in visualization of the aortic valve. Practical tips and tricks about aortic valve imaging with cardiac CTA are given. Topics include optimization of patient preparation and image acquisition; strengths and limitations of standard postprocessing techniques such as multiplanar reconstruction, maximal intensity projection, and minimum intensity projection; and use of advanced volume rendering with BPI for assessment of aortic valve disease.

Anomalous intracavitary right coronary artery shown by cardiac CT: A potential hazard to be aware of before various interventions

Intracavitary right coronary arteries (RCAs) are uncommon (incidence of 0.09%-0.1%), having previously been reported nearly exclusively in autopsy series. However, more recently this entity has been detected prospectively by noninvasive cardiac computed tomography. Because many interventional procedures, including pacemaker placement and atrial flutter ablation, may be influenced by the presence of an intracavitary RCA, this entity is important to recognize. We report two cases of intracavitary right coronary artery discovered prospectively by cardiac computed tomography. In one of these cases, interventional management was altered based on our findings.

Endocarditis with perforation of a bicuspid aortic valve as shown by cardiac-gated multidetector computed tomography

A previously healthy 35-year-old man sought treatment or fatigue, malaise, and persistent low-grade fevers. Blood ultures obtained were positive for Streptococcus viridans. eports from transthoracic (TTE) and transesophageal chocardiography (TEE) performed at an outside institution howed a bicuspid aortic valve with 1-cm vegetations on ne of the valve cusps and severe aortic insufficiency. He as referred to our institution for aortic valve replacement, nd a cardiac-gated computed tomography angiography CTA) was performed to assess for coronary artery disease.

Iatrogenic intrapericardial diaphragmatic hernia diagnosed by cardiovascular magnetic resonance

Intrapericardial diaphragmatic hernias are very uncommon and are most typically caused by high-force blunt trauma. Other iatrogenic causes such as prior surgical formation of a pericardial window have been described, but are exceedingly rare. We present a case of an intrapericardial diaphragmatic hernia in a patient with a prior pericardial window in which the diagnosis was unclear using conventional imaging modalities, but was established using cardiovascular magnetic resonance.

Primary cardiac lymphoma diagnosed by multiphase-gated cardiac CT and CT-guided percutaneous trans-sternal biopsy

We present a case of a primary cardiac B-cell lymphoma where a multiphase-gated cardiac CT exam helped to successfully guide trans-sternal needle biopsy to establish a tissue diagnosis.