Kristopher W. Cummings

A Pattern-based Approach to Assessment of Delayed Enhancement in Nonischemic Cardiomyopathy at MR Imaging

Although delayed contrast material-enhanced cardiac magnetic resonance (MR) imaging has traditionally been used to evaluate ischemic disease and myocardial viability, it is increasingly being used in the evaluation of nonischemic cardiomyopathies. Unlike myocardial infarction, which demonstrates subendocardial or transmural delayed contrast enhancement in a vascular distribution, nonischemic cardiomyopathies demonstrate enhancement that is not limited to a vascular territory. In combination with other cardiac MR imaging features, the location (subendocardial, transmural, subepicardial, or mesocardial) and pattern (patchy or diffuse) of abnormal delayed myocardial enhancement allow differentiation between ischemic (infarct-related) and nonischemic cardiomyopathies and, in cases of nonischemic cardiomyopathy, narrowing of the differential diagnosis. With use of a structured approach, delayed contrast-enhanced cardiac MR imaging can be helpful in the early detection and appropriate treatment of nonischemic cardiomyopathies.

ACR Appropriateness Criteria® Acute Nonspecific Chest Pain—Low Probability of Coronary Artery Disease

Primary imaging options in patients at low risk for coronary artery disease (CAD) who present with undifferentiated chest pain and without signs of ischemia are functional testing with exercise or pharmacologic stress-based electrocardiography, echocardiography, or myocardial perfusion imaging to exclude myocardial ischemia after rule-out of myocardial infarction and early cardiac CT because of its high negative predictive value to exclude CAD. Although possible, is not conclusive whether triple-rule-out CT (CAD, pulmonary embolism, and aortic dissection) might improve the efficiency of patient management. More advanced noninvasive tests such as cardiac MRI and invasive imaging with transesophageal echocardiography or coronary angiography are rarely indicated. With increased likelihood of noncardiac causes, a number of diagnostic tests, among them ultrasound of the abdomen, MR angiography of the aorta with or without contrast, x-ray rib views, x-ray barium swallow, and upper gastrointestinal series, can also be appropriate. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment. This recommendation is based on excellent evidence, including several randomized comparative effectiveness trials and blinded observational cohort studies.

ACR Appropriateness Criteria Asymptomatic Patient at Risk for Coronary Artery Disease

Atherosclerotic cardiovascular disease is the leading cause of death for both men and women in the United States. Coronary artery disease has a long asymptomatic latent period and early targeted preventive measures can reduce mortality and morbidity. It is important to accurately classify individuals at elevated risk in order to identify those who might benefit from early intervention. Imaging advances have made it possible to detect subclinical coronary atherosclerosis. Coronary artery calcium score correlates closely with overall atherosclerotic burden and provides useful prognostic information for patient management. Our purpose is to discuss use of diagnostic imaging in asymptomatic patients at elevated risk for future cardiovascular events. The goal for these patients is to further refine targeted preventative efforts based on risk. The following imaging modalities are available for evaluating asymptomatic patients at elevated risk: radiography, fluoroscopy, multidetector CT, ultrasound, MRI, cardiac perfusion scintigraphy, echocardiography, and PET. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

ACR Appropriateness Criteria® Imaging for Transcatheter Aortic Valve Replacement

Although aortic valve replacement is the definitive therapy for severe aortic stenosis, almost half of patients with severe aortic stenosis are unable to undergo conventional aortic valve replacement because of advanced age, comorbidities, or prohibitive surgical risk. Treatment options have been recently expanded with the introduction of catheter-based implantation of a bioprosthetic aortic valve, referred to as transcatheter aortic valve replacement. Because this procedure is characterized by lack of exposure of the operative field, image guidance plays a critical role in preprocedural planning. This guideline document evaluates several preintervention imaging examinations that focus on both imaging at the aortic valve plane and planning in the supravalvular aorta and iliofemoral system. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Contraindications and side effects of commonly used medications in coronary CT angiography

For certain clinical applications, coronary CT angiography (CCTA) has become a useful tool for the noninvasive evaluation of coronary artery atherosclerosis. To optimize image quality in CCTA, medications are often given prior to scanning to slow the heart rate or distend the arteries. These medications have side effects and are contraindicated in certain patient populations. Metoprolol is the ß-blocker of choice in CCTA, and it has been shown to be effective in achieving the goal heart rate of less than 65 beats per minute for CCTA and in minimizing variability of heart rate. It is contraindicated in patients with hypotension or high degree AV block, and it must be used with caution in patients with asthma or obstructive pulmonary disease, patients with decompensated heart failure, and those with vasospastic or vasoocclusive disease. Diltiazem, the calcium channel blocker of choice in CCTA, is a reasonable alternative for heart control, particularly in patients with asthma or bronchospastic disease, and patients with orthotopic heart transplants that have been sympathetically denervated. Sublingual nitroglycerin is especially useful in order to dilate distal arteries to improve stenosis visibility. However, it is contraindicated in patients on erectile dysfunction medications and those with severe anemia. It must be used cautiously in patients with aortic stenosis or other preload-dependant cardiac pathologies.

Imaging in blunt cardiac injury: Computed tomographic findings in cardiac contusion and associated injuries

BACKGROUND Blunt cardiac injury (BCI) may manifest as cardiac contusion or, more rarely, as pericardial or myocardial rupture. Computed tomography (CT) is performed in the vast majority of blunt trauma patients, but the imaging features of cardiac contusion are not well described. PURPOSE To evaluate CT findings and associated injuries in patients with clinically diagnosed BCI. MATERIALS AND METHODS We identified 42 patients with blunt cardiac injury from our institutions electronic medical record. Clinical parameters, echocardiography results, and laboratory tests were recorded. Two blinded reviewers analyzed chest CTs performed in these patients for myocardial hypoenhancement and associated injuries. RESULTS CT findings of severe thoracic trauma are commonly present in patients with severe BCI; 82% of patients with ECG, cardiac enzyme, and echocardiographic evidence of BCI had abnormalities of the heart or pericardium on CT; 73% had anterior rib fractures, and 64% had pulmonary contusions. Sternal fractures were only seen in 36% of such patients. However, myocardial hypoenhancement on CT is poorly sensitive for those patients with cardiac contusion: 0% of right ventricular contusions and 22% of left ventricular contusions seen on echocardiography were identified on CT. CONCLUSION CT signs of severe thoracic trauma are frequently present in patients with severe BCI and should be regarded as indirect evidence of potential BCI. Direct CT findings of myocardial contusion, i.e. myocardial hypoenhancement, are poorly sensitive and should not be used as a screening tool. However, some left ventricular contusions can be seen on CT, and these patients could undergo echocardiography or cardiac MRI to evaluate for wall motion abnormalities.

Cardiovascular magnetic resonance with an MR compatible pacemaker

Magnetic resonance imaging (MRI) within FDA guidelines for the MRI-conditional pacemaker precludes placing the heart at the center of the magnet’s bore. This in effect appears to preclude cardiovascular MR. In this manuscript, we describe a protocol for cardiovascular MR of patients with a Revo pacemaker system while operating within FDA guidelines, and the first US case of cardiovascular MR in a patient with a Revo MRI-conditional pacing system despite position constraints.

Role of imaging in the diagnosis and management of parasitic infections.

Purpose of review This article reviews the imaging findings of common parasitic infections of the lung with a focus on the radiographic and computed tomography (CT) appearances in the context of the life cycle and pathophysiology of each organism. Recent findings Parasitic infections are often confused for more common diseases of the lung including community acquired pneumonia or malignancy. With increasing global travel and ecotourism, occasional outbreaks of new parasitic infections, and varying times to onset of symptoms, these diseases can present anywhere. With increasing use of lung CT, more information is now known about the imaging findings in parasitic diseases and subtle clues that are often present and can help distinguish them from their more common mimickers. Summary This review summarizes the imaging appearances of common parasitic lung infections based on current literature.

Pulmonary Vascular Diseases

Pulmonary vascular diseases encompass a large and diverse group of underlying pathologies ranging from venous thromboembolism to congenital malformations to inflammatory vasculitides. As a result, patients can present either acutely with dyspnea and chest pain or chronically with dyspnea on exertion, hypoxia, and right heart failure. Imaging, particularly with multidetector CT, plays a key role in the evaluation and management of patients with suspected pulmonary vascular disease and, given the widespread routine use of high-quality CT pulmonary angiography, it is imperative that radiologists be familiar these pathologies.

Posttraumatic anomalous pulmonary edema.

Focal pulmonary edema from increased venous hydrostatic pressure is most commonly seen in mitral valve regurgitation (in the right upper lobe) or in pulmonary venous obstruction/compression from neoplastic, fibrotic, or iatrogenic causes (in any lobe). We describe a case of focal pulmonary edema of the left upper lobe in a patient with partial anomalous pulmonary venous return of the left superior pulmonary vein, where the draining left brachiocephalic vein was compressed by a subluxed sternoclavicular joint after trauma. In this case, recognition of the focal edema and anomalous pulmonary vein allowed for a diagnosis of clavicular subluxation.