The role of cardiovascular imaging techniques in the assessment of patients with acute chest pain

Chest pain is the most common presenting symptom of coronary artery disease. The assessment and appropriate management of patients with acute chest pain and non-diagnostic electrocardiograms (ECGs) remain a continuing clinical problem, with major logistic and financial implications for health-care providers. Cardiovascular imaging is at the forefront of health care, experiencing rapid changes over the recent years, particularly with the use of advanced medical technologies. Imaging techniques like acute rest myocardial perfusion imaging (MPI), echocardiography, electron beam computed tomography (CT), cardiac magnetic resonance imaging (MRI) and multi-detector CT (MDCT) have been used recently in the evaluation and triage of patients with chest pain in addition to the conventional investigations such as ECGs and cardiac biomarkers in the chest pain units. The annual potential cost savings, by incorporating the routine use of acute rest MPI in patients with low-to-moderate risk and non-diagnostic ECGs are substantial. The high negative predictive value of a normal resting MPI in patients with chest pain for myocardial infarction and future cardiac events is well established. Echocardiography is also considered to be useful but the technique is operator dependent and at present there is insufficient data to support its use. Cardiac MRI is expensive and time consuming and there is insufficient diagnostic and prognostic data to make it suitable for chest pain patients at present. There has been increasing interest in MDCT recently, especially with the advent of 64-slice CT but the sensitivity and specificity in chest pain patients are no better than MPI so far.     

Acute pulmonary embolism: imaging in the emergency department

Acute pulmonary embolism (PE) is a life-threatening condition that requires accurate diagnostic imaging. Morbidity and mortality that result from PE can be reduced significantly if appropriate treatment is initiated early; this makes timely diagnosis imperative. Historically, the gold standard for the imaging of PE has been pulmonary angiography. Rapid advances in radiology and nuclear medicine have led to this modality largely being replaced by noninvasive techniques, most frequently multidetector helical CT pulmonary angiography (CTPA). In cases in which CTPA is contraindicated, other modalities for diagnosis of PE include nuclear ventilation perfusion scanning, magnetic resonance pulmonary angiography, duplex Doppler ultrasonography for deep venous thrombosis, and echocardiography. This article reviews the literature on the role of these imaging modalities in the diagnosis of PE.     

Cardiovascular computed tomography in pediatric congenital heart disease: A state of the art review

Cardiac computed tomography (CCT) has increasingly been used in the assessment of both children and adults with congenital heart disease (CHD), in part due to advances in CCT technology and an increased prevalence of adults with palliated CHD. It serves as a complimentary modality to echocardiography, cardiac magnetic resonance imaging and cardiac catheterization. CCT can provide unique diagnostic information, is less invasive and less likely to require sedation compared to other modalities. Detailed knowledge of individual patient cardiac anatomy, physiology, surgical repair and possible residual lesions are paramount to optimal CCT imaging. This comprehensive review details the use of CCT both pre- and postoperatively for the most common CHD diagnoses. We also aim to highlight some new and innovative technologies that have become available and can further optimize CCT imaging for CHD patients.     

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

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.     

Cardiac CT for the assessment of chest pain: Imaging techniques and clinical results

Immediate and efficient risk stratification and management of patients with acute chest pain in the emergency department is challenging. Traditional management of these patients includes serial ECG, laboratory tests and further on radionuclide perfusion imaging or ECG treadmill testing. Due to the advances of multi-detector CT technology, dedicated coronary CT angiography provides the potential to rapidly and reliably diagnose or exclude acute coronary artery disease. Life-threatening causes of chest pain, such as aortic dissection and pulmonary embolism can simultaneously be assessed with a single scan, sometimes referred to as "triple rule out" scan. With appropriate patient selection, cardiac CT can accurately diagnose heart disease or other sources of chest pain, markedly decrease health care costs, and reliably predict clinical outcomes. This article reviews imaging techniques and clinical results for CT been used to evaluate patients with chest pain entering the emergency department.     

MRI for acute chest pain: Current state of the Art

This article reviews the magnetic resonance imaging (MRI) and angiography (MRA) techniques, imaging findings, and evidence for evaluating patients with acute chest pain due to acute pulmonary embolus (PE), aortic dissection (AD), and myocardial infarction (MI). When computed tomographic angiography (CTA) is contraindicated, MRI and MRA are important alternative imaging modalities for diagnosis and management of patients with acute PE, AD, and MI. Familiarity with the techniques, imaging findings, and evidence is critical to safely and appropriately managing patients presenting with acute chest pain. J. Magn. Reson. Imaging 2013;37:1290–1300. © 2013 Wiley Periodicals, Inc.     

Diagnostik und interventionelle Therapie von Gallengangssteinen

Different imaging modalities recently underwent considerable improvements for the visualization of ductal gallstones. The declining significance of endoscopic retrograde cholangiopancreatography (ERCP) has been accepted unanimously. This paradigm shift is mostly due to improvements in transabdominal ultrasound, the increased availability of endoscopic ultrasound, and the use of magnetic resonance cholangiopancreatography (MRCP). In particular, MRCP is limited only in visualizing very small intraductal gallstones due to spatial resolution restrictions, whereas the detection rate of larger concretions is comparable to that with ERCP and endoscopic ultrasound. Patients with biliary pancreatitis benefit greatly from noninvasive MRCP visualization, establishing it as the preferred imaging modality. Particularly if ductal gallstones requiring further intervention are highly suspected, ERCP is preferable to other imaging modalities. If that suspicion is moderate, MRCP would be the imaging modality of choice, and transabdominal ultrasound would be performed if ductal gallstones are considered improbable. In up to 90% of cases, removal can be achieved endoscopically. Using a percutaneous approach smaller concretions can be extracted directly. However, larger gallstones need to be broken down into smaller fragments. For lithotripsy, either cholangioscopically-guided laser or electrohydraulic procedures are easy and effective. In case of strictures due to biliodigestive anastomoses, additional papillary balloon dilatation may be required.     

Cardiac imaging

The emergence of noninvasive imaging techniques for the definitive diagnosis and monitoring of cardiovascular disease has greatly altered cardiac imaging in the past 25 years. The practice of cardiac imaging in 1975 was centered on conventional radiography and angiography, but, in the past 2 decades, noninvasive techniques have substantially replaced catheterization and angiography. The reliance on echocardiography for the evaluation of many cardiac diseases had a profoundly negative influence on the role of the radiologist in cardiac imaging, since the exercise of this modality has been a nearly exclusive province of the cardiologist. However, in the past decade, magnetic resonance imaging has been gradually assuming more importance in cardiovascular diagnosis; with this increase in importance, the role of the radiologist has been reactivated. In 1975, fellowship training in cardiac imaging was frequently combined with training in angiography. Now, training may be more effective by combining cardiac and pulmonary imaging in a thoracic imaging fellowship, but cross-training with an associated subspeciality will be influenced by priorities and personnel in various departments.     

Imaging of the knee

MR imaging has become the primary imaging modality of the knee. Its advantages include its noninvasive nature, multiplanar imaging capability, excellent soft-tissue contrast, and high resolution. The need for multiple imaging modalities is obviated, as the menisci, cruciate ligaments, synovium, articular cartilage, marrow, and periarticular soft tissues can be simultaneously evaluated. Other imaging modalities may occasionally be helpful in the evaluation of specific problems including CT in tibial plateau fractures, real-time ultrasound for the confirmation of a popliteal cyst or popliteal artery aneurysm, and arthrography for the detection of prosthetic joint loosening.     

Magnetic resonance imaging of the spine: applications and limitations

MRI is a unique, noninvasive imaging modality that has already received wide application in the evaluation of abnormalities involving the spinal axis. It is the procedure of choice in the evaluation of suspected syringomyelia, Chiari malformation, and disk space infection. MRI is the only imaging modality presently capable of imaging multiple sclerosis plaques involving the spinal cord and is the only noninvasive modality that can diagnose nonherniated degenerated disks. MRI may provide valuable information in degenerative diseases of the spine, tumors of the spinal axis, and other congenital abnormalities, as either a primary or adjuvant imaging modality. Further investigation is needed to define the role of MRI in the evaluation of the traumatized and postoperative spine. Surface coil techniques hold promise in alleviating the present shortcomings of MRI, which are related primarily to slice thickness and attendant partial volume averaging. Chemical shift imaging may also be useful in accentuating subtle contrast differences between tissues and therefore highlighting abnormalities.     

Role and limitations of plain radiography in chest radiology]

Despite the recent development of diagnostic modalities such as CT and MRI, plain radiography continues to play an important role in chest radiology. Chest radiography remains the imaging modality of choice for initial examinations because it offers simplicity, low cost, and a large amount of information. It is important for radiologists to understand normal anatomy and variants simulating disease to avoid false-positive interpretations of chest radiographs and unnecessary CT examinations. It should be noted that many cases can be diagnosed correctly by chest radiographs alone. Only after careful evaluation of an abnormality on chest radiograph should CT examination be performed. We should also be aware that some serious chest diseases, including miliary tuberculosis, can present normal chest radiographs in the early stage. In such patients with respiratory symptoms, even when the chest radiograph is negative, CT examination should be performed promptly to avoid disease progression.     

The integration of positron emission tomography into noninvasive cardiovascular diagnosis]

Cardiac positron emission tomography is a noninvasive imaging modality that can be used to assess regional myocardial blood flow and metabolism. This combined noninvasive approach to the evaluation of acute or chronic injury to the myocardium is superior to all other imaging modalities. With increasingly widespread use of positron emission tomography it is becoming evident that patients with impaired left ventricular ejection fraction (less than or equal to 35%) resulting from congestive heart failure and patients soon (72-96 h) after acute myocardial infarction in particular may benefit from definition of metabolically active myocardium to stratify therapeutic assessment.     

Triple rule-out CT in the emergency department: protocols and spectrum of imaging findings

Triage decisions in patients suffering from acute chest pain remain a challenge. The patient’s history, initial cardiac enzyme levels, or initial electrocardiograms (ECG) often do not allow selecting the patients in whom further tests are needed. Numerous vascular and non-vascular chest problems, such as pulmonary embolism (PE), aortic dissection, or acute coronary syndrome, as well as pulmonary, pleural, or osseous lesions, must be taken into account. Nowadays, contrast-enhanced multi-detector-row computed tomography (CT) has replaced previous invasive diagnostic procedures and currently represents the imaging modality of choice when the clinical suspicion of PE or acute aortic syndrome is raised. At the same time, CT is capable of detecting a multitude of non-vascular causes of acute chest pain, such as pneumonia, pericarditis, or fractures. Recent technical advances in CT technology have also shown great advantages for non-invasive imaging of the coronary arteries. In patients with acute chest pain, the optimization of triage decisions and cost-effectiveness using cardiac CT in the emergency department have been repetitively demonstrated. Triple rule-out CT denominates an ECG-gated protocol that allows for the depiction of the pulmonary arteries, thoracic aorta, and coronary arteries within a single examination. This can be accomplished through the use of a dedicated contrast media administration regimen resulting in a simultaneous attenuation of the three vessel territories. This review is intended to demonstrate CT parameters and contrast media administration protocols for performing a triple rule-out CT and discusses radiation dose issues pertinent to the protocol. Typical life-threatening and non-life-threatening diseases causing acute chest pain are illustrated.     

CT coronary angiography: indications, image acquisition, and interpretation

Intense scientific and clinical evaluation have brought about great improvements in cardiac CT. This is no longer merely an experimental technique, rather it has become a clinical application that is ready to fulfill its promise of replacing invasive cardiac catheterization in certain patient populations. Among the proven indications is the evaluation of patients with atypical chest pain, the morphological evaluation of the coronary arteries in cases of suspected congenital anomalies, and before surgical intervention, as well as the evaluation of coronary revascularizations. The use of CT angiography for the exhaustive evaluation of cardiac and non-cardiac pathology in patients with acute chest pain in the emergency department is currently being investigated. Because the heart is continuously moving, CT coronary angiography represents a greater technical challenge than other applications of CT. On the other hand, rapid technical development requires acquisition protocols to be adjusted constantly. However, users that know the general techniques of computed tomography can overcome these challenges. The aim of this article is to provide those interested and involved in CT angiography with a manual to enable them to follow our method step by step. We include considerations regarding the correct selection of patients, patient medication, radiological protection, contrast enhancement, acquisition and reconstruction parameters, image display, image analysis techniques, and the radiological report. Our recommendations are based on our experience, which runs from the evolution of multiple-row detector CT scanners for cardiac applications from its beginnings to the most modern presentations of advanced acquisition modalities, including dual-source CT, which we consider to be the precursor of this test in routine clinical practice.     

Congenital diseases of the thoracic aorta. Role of MRI and MRA

Aortic malformations may be associated with other congenital heart abnormalities or may present independently, as incidental findings in asymptomatic patients. For more than 30 years, conventional imaging techniques for detection and assessment of congenital anomalies of the aorta have been chest X-ray, echocardiography and angiography. In recent times, considerable interest in congenital aortic diseases has been shown, due to technical progresses of noninvasive imaging modalities. Among them, magnetic resonance imaging (MRI) almost certainly offers the greatest advantages, especially in young patients in which a radiation exposure must be avoided as much as possible. MRI provides an excellent visualization of vascular structures with a wide field of view, well suited for evaluation of the thoracic aorta malformations. With the implementation of magnetic resonance angiography (MRA) it is also possible to depict any relationship with supra-aortic or mediastinal vessels. Phase contrast technique allows identification of the hemodynamic significance of the aortic alteration. Some technical considerations, which include fast spin-echo, gradient-echo and, especially, MRA techniques with phase-contrast and contrast enhanced methods, are discussed and applied in the evaluation of congenital thoracic aorta diseases.     

Multimodality cardiac imaging in the 21st century: evolution,advances and future opportunities for innovation

Cardiovascular imaging has significantly evolved since the turn of the century. Progress in the last two decades has been marked by advances in every modality used to image the heart, including echocardiography, cardiac magnetic resonance, cardiac CT and nuclear cardiology. There has also been a dramatic increase in hybrid and fusion modalities that leverage the unique capabilities of two imaging techniques simultaneously, as well as the incorporation of artificial intelligence and machine learning into the clinical workflow. These advances in non-invasive cardiac imaging have guided patient management and improved clinical outcomes. The technological developments of the past 20 years have also given rise to new imaging subspecialities and increased the demand for dedicated cardiac imagers who are cross-trained in multiple modalities. This state-of-the-art review summarizes the evolution of multimodality cardiac imaging in the 21st century and highlights opportunities for future innovation.     

胸部CR图像窗宽、窗位的后处理

目的 探讨窗宽、窗位在胸部CR图像后处理的应用方法和效果。方法 对100例患者胸部正，侧位图像应用相应3种后处理方法（分别为常规胸片后处理，软组织、肋骨、纵隔片的后处理，病灶片后处理），由两位副主任技师和两位副主任医师对这些后处理的胸部CR胶片图像进行分析，评价后处理方法的优缺点。结果 这3种方法对胸部CR图像的后处理使相应的胸部CR图像对比度适当，清晰度提高，充分显示病变。结论 这3种后处理方法正确应用可保证胸部CR图像质量，更好地满足诊断要求。     

MR imaging of adult patients with congenital heart disease

Although the incidence of congenital heart disease remains constant among newborns, improved medical and surgical techniques have dramatically prolonged life expectancy and produced a new, growing group of patients harboring these lesions: adults with congenital heart disease. Conventional imaging techniques in these patients may be limited because of patient size, chest configuration, or poor ventricular function. MR imaging provides a noninvasive means of directly demonstrating their developmental abnormalities and the sequelae of pathophysiologic changes caused by these lesions. Combined use of spin echo and gradient reversal echo acquisition techniques allows complete evaluation of cardiac morphology and function in these patients. An new medical and surgical therapies prolong the lives of these patients, the role of MR imaging for physiologic assessment and surgical planning will expand further.     

Noncardiac findings on cardiac CT part I: Pros and cons

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 imaging modalities include its ability to evaluate directly the coronary arteries and to provide an opportunity to evaluate extracardiac structures, such as the lungs and mediastinum. Some centers reconstruct a small field of view (FOV) cropped around the heart, but a full FOV (from skin to skin in the irradiated area) 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 evaluation. 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 two-part review we outline the issues surrounding the concept of the noncardiac read looking for noncardiac findings on cardiac CT. Part I focuses on the pros and cons of the practice of identifying noncardiac findings on cardiac CT.     

MRI of the pancreas: Problem solving tool

Advances in MR hardware and pulse sequence design over the years have improved the quality and robustness of MR imaging of the pancreas. Today, MRI is an indispensible tool for studying the pancreas and can provide useful information not attainable with other noninvasive or minimally invasive imaging techniques. In the present review, specific cases are reviewed where the strengths of MRI demonstrate the utility of this imaging modality as a problem solving tool. J. Magn. Reson. Imaging 2012;36:1037–1051. © 2012 Wiley Periodicals, Inc.