Cardiac MRI in Pulmonary Hypertension: From Magnet to Bedside

Pulmonary hypertension (PH) is a disease characterized by progressive rise of pulmonary artery (PA) pressure, which can lead to right ventricular (RV) failure. It is usually diagnosed late because of the nonspecificity of its symptoms. RV performance and adaptation to an increased afterload, reflecting the interaction of the PA and RV as a morphofunctional unit, constitute a critical determinant of morbidity and mortality in these patients. Therefore, early detection of dysfunction may prevent treatment failure. Cardiac MRI constitutes one of the most complete diagnostic modalities for diagnosing PH. It allows evaluation of the morphology and hemodynamics of the PA and RV. Several cine steady-state free-precession (SSFP)-derived parameters (indexed RV end-diastolic volume or RV systolic volume) and phase-contrast regional area change have been suggested as powerful biomarkers for prognosis and treatment. Recently, new cardiac MRI sequences have been added to clinical protocols for PH evaluation, providing brand-new information. Strain analysis with myocardial feature tracking can help detect early RV dysfunction, even with preserved ejection fraction. Four-dimensional flow cardiac MRI can enhance assessment of advanced RV and PA hemodynamics. Late gadolinium enhancement (LGE) imaging may allow detection of replacement fibrosis in PH patients, which is associated with poor outcome. T1 mapping may help detect interstitial fibrosis, even with normal LGE imaging results. The authors analyze the imaging workup of PH with a focus on the role of morphologic and functional cardiac MRI in diagnosis and management of PH, including some of the newer techniques. Online supplemental material is available for this article. ^©RSNA, 2020.

Coronary-cameral fistula with double-chambered right ventricle: appearance on cardiac magnetic resonance imaging and 3D printed anatomic modeling

The present case illustrates cardiac magnetic resonance imaging (MRI) and three-dimensional (3D) printed anatomic model findings of a coronary-cameral fistula (CCF) and double-chambered right ventricle (DCRV). A pregnant woman presented with palpitations and near syncope. A non-contrast cardiac MRI showed CCF connecting to a DCRV. Post-delivery, the patient had a contrast-enhanced MRI and 3D printed anatomic model to better evaluate her aberrant anatomy.

Approach to Pulmonary Hypertension: From CT to Clinical Diagnosis

Pulmonary hypertension (PH) is a condition characterized by increased pressure in the pulmonary circulation. It may be idiopathic or arise in the setting of other clinical conditions. Patients with PH tend to present with nonspecific cardiovascular or respiratory symptoms. The clinical classification of PH was recently revised at the World Health Organization symposium in Nice, France, in 2013. That consensus statement provided an updated classification based on the shared hemodynamic characteristics and management of the different categories of PH. Some features seen at computed tomography (CT) can suggest a subtype or probable cause of PH that may facilitate placing the patient in the correct category. These features include findings in the pulmonary arteries (peripheral calcification, peripheral dilatation, eccentric filling defects, intra-arterial soft tissue), lung parenchyma (centrilobular nodules, mosaic attenuation, interlobular septal thickening, bronchiectasis, subpleural peripheral opacities, ground-glass opacities, diffuse nodules), heart (congenital lesions, left heart disease, valvular disease), and mediastinum (hypertrophied bronchial arteries). An approach based on identification of these CT features in patients with PH will allow the radiologist to play an important role in diagnosis and help guide the clinician in management of PH. ^©RSNA, 2018.

Cardiac magnetic resonance imaging abnormalities in systemic lupus erythematosus: a preliminary report

The purpose of this prospective, pilot study was to determine whether differences in myocardial T2 relaxivity can be identified among active systemic lupus erythematosus (SLE) patients with clinically suspected SLE myocarditis, other active SLE patients, inactive SLE patients and age and gender matched controls. Eleven consecutive female patients (six with active SLE and five with inactive SLE), and five age, gender and race matched healthy controls underwent imaging with echocardiography and cardiac magnetic resonance imaging (MRI). Echocardiographic measurements included left ventricular end diastolic (LVEDV) and end systolic volumes (LVESV), and mass (LVM) (all indexed to body mass); ejection fraction and cardiac output. The cardiac MRI measurement was the T2 relaxation time (an index of soft tissue signal, with higher levels suggestive of increased tissue water content). Patients with active SLE had significantly higher LVEDVand LVM than inactive SLE patients and healthy controls, and significantly larger LVESV than healthy controls. Myocardial T2 relaxation times were significantly higher in patients with active SLE compared to those with inactive SLE and to healthy controls, and remained higher even after excluding the two active SLE patients who had clinical myocarditis. The four active SLE patients who underwent repeat cardiac imaging studies after clinical improvement showed normalization of these myocardial abnormalities. The conclusion was that active SLE patients demonstrate abnormalities in myocardial structure manifested by high myocardial T2 relaxation times that normalized after clinical improvement in disease activity. These findings suggest that T2 relaxation values are a sensitive indicator of myocardial disease in patients with SLE and that myocardial T2 relaxation abnormality frequently occur in patients with active SLE, even in the absence of myocardial involvement by clinical criteria.

Penetrating Atherosclerotic Ulcers of the Descending Thoracic Aorta May Be Managed Expectantly

The natural history of penetrating atherosclerotic ulcers (PAUs) of the descending thoracic aorta remains unclear. Between January 1996 and June 2000, PAU was diagnosed in 36 patients (16 men, 20 women; mean age 74.9 ± 1.5 years) at Washington University. Imaging studies and hospital records were reviewed. Late follow-up was by search of the Social Security Death Index and telephone interview. None of 16 asymptomatic patients underwent operation. At follow-up (median 457 days), 6 patients had died of unrelated and 2 of unknown causes. Among 20 symptomatic patients, 10 had associated intramural hematoma (5) or dissection (5), of whom 3 underwent operation. At median follow-up (448 days), the 7 unoperated patients remained alive without an aortic operation. Among the remaining 10 symptomatic patients, 3 had an aortic operation and 2 died of unknown causes during follow-up (median 586 days). These data suggest that, in selected cases, PAU may be managed expectantly with careful observation.

A 43-year-old man with antisynthetase syndrome presenting with acute worsening of dyspnea

A 43-year-old man with antisynthetase syndrome was seen in our pulmonary clinic for worsening dyspnea. He was recently diagnosed with antisynthetase syndrome because he had nonspecific interstitial pneumonitis on a surgical lung biopsy and polymyositis associated with anti-Jo-1 and anti-SSA-52 autoantibodies. Along with his worsening dyspnea, he also had a dry cough, lower extremity edema, and abdominal distension. He had gained 11 kg over 1 month. He had been taking prednisone 40 mg daily 2 months prior, which had been recently weaned to 20 mg daily. He had also been on mycophenolate mofetil but had recently discontinued it on his own.

Asbestos-related lung disease: a pictorial review

Asbestos exposure can lead to a variety of adverse effects in the thorax. Although currently in the western world, levels of exposure are kept in check by strict regulations, history of previous asbestos exposure continues to have an effect on many, owing to the latent nature of the pathophysiological response of the body to the inhaled fibers. The adverse effects of asbestos generally fall under 3 categories: pleural disease, lung parenchymal disease, and neoplastic disease. Effects on the pleura include pleural effusions, plaques, and diffuse pleural thickening. In the parenchyma, rounded atelectasis, fibrotic bands, and asbestosis are observed. Differentiating asbestosis from other forms of interstitial lung diseases, such as idiopathic pulmonary fibrosis, usual interstitial pneumonia, smoking-related lung disease, and mixed interstitial lung diseases, is important because the prognosis, course of disease, and management of the patient should be tailored based on the specific etiology of the disease. In this review, imaging findings specific to asbestosis are discussed. Finally, exposure to asbestos can lead to neoplastic disease such as pleural mesothelioma, peritoneal mesothelioma, and bronchogenic carcinoma. The purpose of this article is to review the effects of asbestos exposure in the thorax, pathophysiology of these responses, and disease course. Particular emphasis is placed on the radiographic appearance of the disease, discussion of various imaging modalities and their utility, and the role of imaging in the management of patients with previous asbestos exposure and asbestos-related pulmonary disease.

Primary pericardial tumors

Primary pericardial tumors are rare and may be classified as benign or malignant. The most common benign lesions are pericardial cysts and lipomas. Mesothelioma is the most common primary malignant pericardial neoplasm. Other malignant tumors include a wide variety of sarcomas, lymphoma, and primitive neuroectodermal tumor. When present, signs and symptoms are generally nonspecific. Patients often present with dyspnea, chest pain, palpitations, fever, or weight loss. Although the imaging approach usually begins with plain radiography of the chest or transthoracic echocardiography, the value of these imaging modalities is limited. Cross-sectional imaging, on the other hand, plays a key role in the evaluation of these lesions. Computed tomography and magnetic resonance imaging allow further characterization and may, in some cases, provide diagnostic findings. Furthermore, the importance of cross-sectional imaging lies in assessing the exact location of the tumor in relation to neighboring structures. Both benign and malignant tumors may result in compression of vital mediastinal structures. Malignant lesions may also directly invade structures, such as the myocardium and great vessels, and result in metastatic disease. Imaging plays an important role in the detection, characterization, and staging of pericardial tumors; in their treatment planning; and in the posttreatment follow-up of affected patients. The prognosis of patients with benign tumors is good, even in the few cases in which surgical intervention is required. On the other hand, the length of survival for patients with malignant pericardial tumors is, in the majority of cases, dismal.

Tumors of the pulmonary artery and veins

The pulmonary vasculature may be involved by different primary and secondary tumors. Poorly differentiated and undifferentiated sarcomas are the most common primary tumors of the pulmonary arteries. They tend to affect the large caliber pulmonary vessels and present with predominantly intraluminal growth. Pulmonary and mediastinal metastasis are common, and prognosis is poor. Clinical and imaging manifestations may mimic those of pulmonary embolism. Dyspnea, chest pain, cough, and hemoptysis are the most common presenting symptoms. Primary sarcomas arising from the central pulmonary veins are less common than their arterial counterpart. Secondary involvement of the pulmonary arteries and veins by primary and metastatic pulmonary malignancies is more common. Tumoral embolism may also affect the pulmonary arteries. They may develop from different intrathoracic and extrathoracic malignancies and may be indistinguishable from venous thromboembolism. It may manifest as cor pulmonale with right cardiac strain and dilated pulmonary arteries. Computed tomography, magnetic resonance imaging, and fluorodeoxyglucose positron emission tomography may help in the differentiation between these 2 conditions.

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.

Non-Coronary Cardiac CT Imaging

Cardiac multidetector CT (MDCT) has moved from purely anatomic imaging, to assessment of cardiac function. Significant advances since the advent of multidetector CT now make it feasible to assess not only the coronary arteries, but also ejection fraction, ventricular volumes, myocardial mass and the presence of wall-motion abnormalities. Advances include improvements in EKG-gating, including improvements in temporal resolution, as well as the addition of delayed contrast-enhanced methods. Anatomic imaging has improved as well, with thinner collimation and better reconstruction methods. Three-dimensional software programs now permit excellent surface rendered displays and multiplanar reconstructions suitable as surgical and procedural "road maps."

CT Depiction of Pulmonary Emboli: Display Window Settings

PURPOSE

To compare computed tomographic (CT) window settings selected by radiologists with those determined by using two alternative approaches for depiction of pulmonary emboli (PE).

MATERIALS AND METHODS

Institutional review board approval was obtained; informed consent was not required. This study was compliant with the Health Insurance Portability and Accountability Act. Twenty-five clinical chest CT studies were obtained with a standardized PE protocol and retrospectively evaluated by five chest and two body CT radiologists. Of these studies, 13 were positive for PE, and 12 were negative. At the main pulmonary artery (PA), mean attenuations (MPA) and standard deviations (SDPA) were measured. Initially, images were displayed with a standard mediastinal window setting (window width, W = 400 HU; window center, C = 30 HU), and each observer adjusted the setting to a personally preferred setting (eg, "personal") for PE detection. Images displayed at this setting were compared in a side-by-side fashion with the "modified" (W = MPA + 2 . SDPA, C = W/2) and "double-half" (W = 2 . MPA, C = MPA/2) window setting. Each observer rated images from 1 (ie, most preferred) to 3 (ie, least preferred). For quantitative analysis, window width and center value of each setting were divided by corresponding MPA to compute a width ratio and a center ratio. Window settings and ratings were compared with repeated-measures analysis of variance, paired t tests, and Wilcoxon signed-rank tests.

RESULTS

Ratings for all three types of window settings were significantly different (P < .001). Observers preferred their personal settings the most and the modified settings the least. Mean ratios for the seven observers were 1.68 +/- 0.20 for window width and 0.47 +/- 0.08 for window center. Window width ratios for all settings were significantly different from each other (P < .001). Window center ratios were significantly higher for the modified setting than for the double-half setting (P = .013). Values for mean PA attenuation were correlated with window width ratios for six (86%) observers (mean r2 value = 0.29 +/- 0.19, P < or = .03) and with window center ratios for four (57%) observers (mean r2 value = 0.16 +/- 0.14, P < or = .02), thus indicating a trend of setting window width and window center higher when contrast enhancement is lower and vice versa.

CONCLUSION

On average, observers selected CT window settings for PE detection at a window width of slightly less than twice the mean PA attenuation and at a window center of about half the mean PA attenuation. Observers tended to use larger window widths and centers as the degree of PA enhancement was lower.

Amplatzer atrial septal defect occluder for pediatric patients: radiographic appearance

PURPOSE

To describe the chest radiographic appearance of the Amplatzer septal occluder (ASO) (AGA Medical Corporation, Golden Valley, Minn) for atrial septal defects (ASDs) in pediatric patients.

MATERIALS AND METHODS

Two radiologists independently reviewed frontal and lateral chest radiographs obtained in young patients 24 hours after transcatheter ASD closure with the ASO. The appearance (flat disks or dots) and location of the ASO were recorded. The location was related to that of a thoracic vertebral body on frontal and lateral chest radiographs and to a line drawn between the anterior margin of the right hilum and the posterior margin of the inferior vena cava (hilar-caval line) on lateral radiographs; this line corresponded to the expected position of the interatrial septum. The relationship between ASO appearance and patient age was assessed with logistic regression and cumulative probability plots.

RESULTS

Sixty-eight pediatric patients (age range, 1 month to 18 years; mean age, 4.2 years; 24 boys and 44 girls) were included. On frontal radiographs, the ASO center projected between T7 and T9, either to the right of or over the spinous processes of the vertebral body. On lateral radiographs, the ASO projected over (n = 66) or anterior to (n = 2) the hilar-caval line. On frontal radiographs, it appeared as one or two flat disks (n = 61) or as two metallic dots (n = 7). On lateral radiographs, it appeared as two flat disks (n = 54) or as two metallic dots (n = 14). The relationship between increasing patient age and the metallic dot appearance on frontal and lateral radiographs and on the combination of frontal and lateral radiographs was highly significant in each case (P < .001, likelihood ratio chi(2) test), with r(2) values of 0.35, 0.20, and 0.28, respectively. ASDs were successfully occluded with the ASO in all patients except one, in whom trivial shunting was seen at 12-month follow-up.

CONCLUSION

The ASO in pediatric patients has a characteristic radiographic appearance when properly positioned.

How to plan and perform a cardiac MR imaging examination

Because of the enormous economic and social impact of cardiovascular disease in the United States there is a need for improved noninvasive diagnosis. Cardiac MR imaging isa versatile, comprehensive technique for assessing cardiac morphology and function. With an understanding of cardiac anatomy and physiology and MR imaging physical principles,cardiac MR imaging can be performed and can play an important role in patient management. This article provides the reader with a basic understanding of cardiac MR imaging and the practical applications required to perform cardiac MR imaging.

MDCT Evaluation of Thoracic Aortic Anomalies in Pediatric Patients and Young Adults:Comparison of Axial, Multiplanar, and 3D Images

OBJECTIVE

The objective of our study was to compare accuracies of axial, multiplanar, and 3D volume-rendered images in the diagnosis of thoracic aortic anomalies in pediatric patients and young adults.

MATERIALS AND METHODS

Fourteen patients, 17 days to 20 years old, with thoracic aortic anomalies underwent MDCT using axial, multiplanar, and 3D volume-rendering imaging. All images were reviewed by three radiologists for position of the aortic arch, coarctation, vascular compression of the airway, collateral vessel formation, and aortopulmonary shunts (patent ductus arteriosus). Final diagnosis was determined by echocardiography, conventional angiography, bronchoscopy, or surgery. Diagnostic accuracy, sensitivity, and interobserver agreement were evaluated.

RESULTS

Average accuracies (average of the three observers for a correct diagnosis) were greater than or equal to 96% for diagnoses of aortic position and airway narrowing on all image types. For the diagnosis of coarctation, average sensitivities (average of the three observers for a true diagnosis) were 73% for axial, 100% for multiplanar, and 100% for 3D volume-rendered images. For the diagnosis of patent ductus arteriosus, average sensitivities were 78% for axial, 94% for multiplanar, and 89% for 3D volume-rendered images. No patients in this study had collateral vessel formation. For the diagnosis of absence of collateral vessel formation, average sensitivities were 100% for axial, 100% for multiplanar, and 100% for 3D volume-rendered images. There were no significant statistical differences in diagnostic performances, agreement with truth, or confidence scores among observers or imaging formats (p > 0.05).

CONCLUSION

Axial, multiplanar, and 3D volume-rendered images serve equally well as methods for assessing the side of the aorta to diagnose anomalies. For evaluation of coarctation and patent ductus arteriosus, multiplanar and 3D volume-rendered images perform slightly better than axial images.

Radiologic findings of 2 commonly used cardiac septal occluders with clinical correlation

Transcatheter closure of an atrial septal defect, patent foramen ovale, or post-myocardial infarction ventricular septal defect has become a safe and effective alternative to medical and surgical therapy. Although the use of transcatheter closure of septal defects is becoming increasingly more popular, there are few reports of the radiographic appearance of the closure devices. We report the chest radiographic findings in 36 patients after transcatheter closure of septal defects with Amplatzer or CardioSEAL occluders in an effort to aid radiologists in recognizing the appearances of these devices and enable them to confirm proper positioning.

Primary leiomyosarcoma of the pulmonary artery: a diagnostic dilemma

Primary leiomyosarcoma of the pulmonary artery is a rare malignancy arising from the multipotential mesenchymal cell of the intima of the pulmonary artery. Due to its rarity and nonspecific clinical symptoms, the correct diagnosis and proper management are often delayed. Furthermore, it is frequently misdiagnosed as pulmonary embolism, mediastinal mass, pulmonary stenosis and lung cancer. Therefore, it is important to consider primary leiomyosarcoma of the pulmonary artery a possibility when a persistent filling defect is present in the pulmonary artery and there is no response to optimal anticoagulation treatment. Radiologic findings such as a unilateral mass continuously filling the pulmonary artery, inhomogenous enhancement, vascular distension, extravascular invasion into adjacent structure or uptake in the area of tumor on the FDG-PET can be helpful when differentiating pulmonary artery sarcoma (PAS) from chronic thromboembolism.

Performing cardiac MR imaging: an overview

Because of the enormous economic and social impact of cardiovascular disease in the United States, there is a need for improved noninvasive diagnosis. Cardiac MR imaging is a versatile, comprehensive technique for assessing cardiac morphology and function. With an understanding of cardiac anatomy and physiology as well as MR physical principles, cardiac MR imaging can be performed and play an important role in patient management.

Magnetic resonance imaging of cyanotic and noncyanotic congenital heart disease

MRI has become an important imaging tool that complements echocardiography in the noninvasive evaluation of congenital heart defects. It can play a crucial role in diagnosis by assessing anatomic and functional features in CHD and identifying complications and postoperative sequelae. The performance and application of cardiac MRI require not only knowledge of the clinical question that needs to be addressed but knowledge of the anatomic characteristics of a variety of congenital heart lesions. A knowledge of the advantages and disadvantages of the different imaging sequences also is important so as to optimize and expedite the examination.

Post-lung transplantation bronchiolitis obliterans syndrome: usefulness of expiratory thin-section CT for diagnosis

PURPOSE

To assess the usefulness of thin-section expiratory computed tomography (CT), as compared with that of thin-section inspiratory CT, in detecting airway obstruction and air trapping in pediatric lung transplant recipients with bronchiolitis obliterans syndrome (BOS).

MATERIALS AND METHODS

Thin-section CT scans were obtained at full inspiration and end expiration in 21 pediatric lung transplant recipients with proved BOS and in 41 transplant recipients with normal airways. True diagnosis was based on pulmonary function test results. Inspiration CT scans were scored for extent of decreased attenuation of the lung parenchyma; expiration CT scans were scored for extent of air trapping.

RESULTS

The sensitivity of inspiratory CT for enabling diagnosis of BOS was 71%; the specificity, 78%; the positive predictive value, 62%; and the negative predictive value, 84%. The sensitivity of expiratory CT for enabling diagnosis of BOS was 100%; the specificity, 71%; the positive predictive value, 64%; and the negative predictive value, 100%. Expiratory CT scores correlated more strongly (rho = 0.75, P <.01) with pulmonary function test-based scores than did inspiratory CT scores (rho = 0.48, P <.01). Nominal logistic regression analysis revealed that expiratory CT was a more powerful predictor of true diagnosis (P <.01) than was inspiratory CT (P =.10).

CONCLUSION

Expiratory CT is sensitive for depicting BOS-related airway abnormalities and may be more useful than inspiratory CT for diagnosis of small airway obstruction.

Metastatic involvement of the heart and pericardium: CT and MR imaging

Metastases to the heart and pericardium are much more common than primary cardiac tumors and are generally associated with a poor prognosis. Tumors that are most likely to involve the heart and pericardium include cancers of the lung and breast, melanoma, and lymphoma. Tumor may involve the heart and pericardium by one of four pathways: retrograde lymphatic extension, hematogenous spread, direct contiguous extension, or transvenous extension. Metastatic involvement of the heart and pericardium may go unrecognized until autopsy. Impairment of cardiac function occurs in approximately 30% of patients and is usually attributable to pericardial effusion. The clinical presentation includes shortness of breath, which may be out of proportion to radiographic findings in patients with pericardial effusion or may be the result of associated pleural effusion. Patients may also present with cough, anterior thoracic pain, pleuritic chest pain, or peripheral edema. The differential diagnosis of pericardial effusion in a patient with known malignancy includes malignant pericardial effusion, radiation-induced pericarditis, drug-induced pericarditis, and idiopathic pericarditis. Any disease process that causes thickening or nodularity of the pericardium or myocardium or masses within the cardiac chambers can mimic metastatic disease.

Detection of CT-proved pulmonary nodules: comparison of selenium-based digital and conventional screen-film chest radiographs

PURPOSE

To compare hard-copy digital chest radiographs obtained with a selenium-based system with wide-latitude asymmetric screen-film radiographs for detection of pulmonary nodules.

MATERIALS AND METHODS

Fifty patients undergoing thoracic computed tomography (CT) for suspected pulmonary nodules were recruited to undergo both digital and screen-film posteroanterior (PA) and lateral chest radiography. Three chest radiologists blinded to the CT results independently reviewed each digital and screen-film radiograph, identified each nodule, and graded their confidence for its presence.

RESULTS

Seventy-eight pulmonary nodules (mean diameter, 1.5 cm; range, 0.5-3.5 cm; 62 soft tissue, 16 calcified) were identified with CT in 34 patients, while 16 patients had clear lungs. The mean sensitivity for the detection of all nodules by all readers (PA and lateral) was 66% (95% Cl, 54%, 76%) for digital radiographs and 64% (95% Cl, 52%, 74%) for screen-film radiographs. Differences between the two techniques were not statistically significant (P > .05, Student t test). There was no difference in mean false-positive-true-positive ratios (PA, 0.35; lateral, 0.53) or positive predictive values (PA, 74%; lateral, 65%), and no significant difference (P > .05) was seen in mean reader confidence rating.

CONCLUSION

In detecting pulmonary nodules, radiologists perform comparably with selenium-based digital and wide-latitude asymmetric screen-film radiographs.

Detection of coronary stenoses on source and projection images using three-dimensional MR angiography with retrospective respiratory gating: preliminary experience

OBJECTIVE

Our objective was to study the ability of three-dimensional MR angiography with retrospective respiratory gating to reveal stenoses in proximal coronary arteries on source and projection images.

CONCLUSION

Proximal coronary artery stenoses can be identified using three-dimensional MR angiography with retrospective respiratory gating, both with projection images and on source images alone. Reasons for missed lesions included collateral vessels and retrograde flow distal to complete occlusion and volume averaging of vessels with adjacent structures. Causes of false-positive interpretations included small foci of decreased signal intensity distal to complete occlusion, partial volume effects on individual partitions, and regions of distal vessels leaving the imaging plane.

Digital subtraction versus film-screen angiography for detecting acute pulmonary emboli: evaluation in a porcine model

PURPOSE

To compare the diagnostic performance of digital subtraction angiography (DSA) to that of film-screen angiography (FSA) for detecting acute pulmonary embolism (PE) in a porcine model.

MATERIALS AND METHODS

DSA and FSA were performed in 13 pigs before and after central venous administration of autologous emboli. Results were compared to findings at necropsy with use of ex vivo pulmonary angiography to guide pathologic sectioning. The sensitivity and predictive value of a positive case for detecting each embolus were computed for each pulmonary artery branch order and compared with use of 95% confidence intervals. Interobserver variability among three readers for individual PE detection was calculated.

RESULTS

Pathologic examination of the lungs revealed 100 total PEs (location by vessel order: 1st = 1, 2nd = 0, 3rd = 15, 4th = 32, > 5th = 52). On average, FSA review identified 72 (72%) emboli and DSA review, 65 (65%). There was no significant difference in sensitivity or predictive value of a positive case between DSA and FSA for detecting emboli (P > .05). There was similar agreement among readers for individual PE detection with DSA (mean, 84%) and FSA (mean, 80%).

CONCLUSION

The diagnostic performance of DSA is equivalent to that of FSA for detecting emboli in porcine PA branches. Interobserver agreement for individual PE detection is similar for both imaging techniques.

Transesophageal echocardiographic and clinical features of aortic intramural hematoma

OBJECTIVE

This study sought to determine the transesophageal echocardiographic features and natural history of patients with aortic intramural hematoma.

METHODS

The transesophageal echocardiograms of all patients who had symptoms indicative of aortic dissection over 6 years were reviewed. Measurements were made of the involved aortic segment in the study patients, and follow-up was obtained.

RESULTS

In patients with aortic intramural hematoma, the wall thickness of the involved segment was significantly greater for descending segments than ascending segments (ascending aorta 7 +/- 2 mm, descending aorta 15 +/- 6 mm, p = 0.0016). In each case, the crescent-shaped intramural hematoma involved one wall predominantly, leading to compression of the aortic lumen. The findings of echolucent areas and displaced intimal calcium were found in the majority of patients. Four of eight patients with intramural hematoma of the ascending aorta were treated medically and four were treated surgically. The 30-day mortality was 50% in the medically treated patients and 0% in the surgically treated group. Four of 11 patients with isolated intramural hematoma of the descending aorta were treated medically and seven were treated surgically. All medically treated and 86% of surgically treated patients were alive at 30 days.

CONCLUSIONS

Aortic intramural hematoma has distinct and identifiable transesophageal echocardiographic features. These data support those of previous studies documenting high morbidity and mortality in patients with aortic intramural hematoma.

Vascular rings in symptomatic children: frequency of chest radiographic findings

PURPOSE

To determine the relative frequency of radiographic findings in symptomatic children with vascular rings.

MATERIALS AND METHODS

Preoperative chest radiographs in 41 children (mean age, 21 months) with surgically proved vascular rings were retrospectively analyzed. There were 41 frontal and 39 lateral radiographs. Lateral views were evaluated for retrotracheal opacity, tracheal narrowing, and anterior tracheal bowing. The aortic arch, descending aorta, and tracheal indentation were assessed on frontal views.

RESULTS

Findings on 39 lateral radiographs included increased retrotracheal opacity on 31 (79%), anterior tracheal bowing on 36 (92%), and tracheal narrowing on 30 (77%) radiographs. All findings were present on 24 (62%) radiographs. Findings on 41 frontal radiographs included right aortic arch on 35 (85%), distal tracheal indentation on 30 (73%), and right descending aorta on 27 (66%) radiographs. All findings were present on 20 (49%) radiographs. Four (10%) frontal radiographs were normal or indeterminate. The combination of frontal and lateral views showed at least one abnormality in every patient. No symptomatic patient with a vascular ring had a normal radiograph.

CONCLUSION

A normal chest radiograph is evidence against the presence of a vascular ring in symptomatic children. Both lateral and frontal radiographs are important in diagnosis.

Coronary arteries: three-dimensional MR imaging with retrospective respiratory gating

Thin-section, three-dimensional (3D) gradient-echo magnetic resonance imaging of the coronary arteries was performed without and with retrospective respiratory gating in 12 healthy volunteers and one patient. In all examinations, results were improved with gating. In five of seven volunteer examinations, coronary artery delineation on images reconstructed by using the least-squares method for motion detection with navigator echoes was found to be equal to that obtained by using edge detection. Images in five other volunteers covered the entire heart with multiple overlapping 3D slabs. The arteries were segmented from the background and could be viewed from any orientation. The lengths of contiguously visible vessels were as follows: left main coronary artery, 11.5 mm +/- 0.4 (mean +/- standard deviation); left anterior descending branch, 115.9 mm +/- 19.7; left circumflex branch, 97.2 mm +/- 12.5; and right coronary artery, 125.9 mm +/- 18.8. This respiratory gating technique clearly improved depiction of the coronary arteries.

Anatomic distribution of pulmonary emboli at pulmonary angiography: implications for cross-sectional imaging

PURPOSE

To determine how often emboli detected angiographically in peripheral pulmonary arterial branches would be missed with cross-sectional imaging.

MATERIALS AND METHODS

Seventy-nine of 88 consecutive pulmonary angiograms interpreted as positive for pulmonary emboli were reviewed retrospectively to detect pulmonary emboli. Three angiograms interpreted as negative when reviewed retrospectively were excluded. Findings of 76 angiograms in 76 patients (32 men, 44 women; aged 19-85 years) were correlated with the results of scintigraphy (n = 72) and Doppler ultrasound (n = 60), clinical presentation (n = 76), and follow-up with chart review (n = 72).

RESULTS

Two hundred five emboli were identified. Nineteen patients had solitary emboli. Sixty emboli were in the upper lobes. The largest arterial branch with pulmonary embolism was lobar in 14 patients, segmental in 38, subsegmental in 20, and smaller in three.

CONCLUSION

If cross-sectional imaging can depict emboli in only segmental and larger arterial branches, then emboli in 23 of 76 patients (30%) would have been missed with cross-sectional imaging.

Aortic dissection: effect of prospective chest radiographic diagnosis on delay to definitive diagnosis

PURPOSE

To determine the effect of the interpretation of plain chest radiographs on the time to definitive diagnosis of aortic dissection.

MATERIALS AND METHODS

The authors evaluated chest radiographs from 75 patients in whom chest radiography was performed before aortic dissection was diagnosed. The radiographs and available comparison images were retrospectively reviewed to identify cases in which aortic dissection should have been suggested before the diagnosis was made.

RESULTS

Radiographic reports suggested that only 19 patients (25%) had an aortic dissection or thoracic aortic aneurysm or needed additional imaging of the aorta. No statistically significant correlation existed between interpretation of the chest radiographs and delay to diagnosis, type of dissection, availability of previously obtained images, or presence of characteristic clinical symptoms. Retrospective analysis showed that the chest radiographs of 36 patients (48%) contained sufficient findings to suggest the diagnosis. In five patients, failure to prospectively suggest dissection was associated with a delay to diagnosis of more than 24 hours.

CONCLUSION

Although prospective interpretation of the chest radiograph shortened the delay to definitive diagnosis for only a limited number of patients, retrospective analysis suggests that the delay can be shortened for additional patients.

Comparison of ventricular mass and function in early versus late repair of coarctation of the aorta

Left ventricular (LV) mass and function in 11 patients (group I) with coarctation of the aorta repaired at a mean age of 35 days were compared with that of 14 patients (group II) who underwent repair at a mean age of 8 years. Each group was compared to age- and sex-matched normal control subjects. All patients were normotensive and had resting arm-leg peak systolic blood pressure gradients < 20 mm Hg. Quantitative M-mode echocardiography was used to determine LV mass index and systolic performance. Magnetic resonance imaging was performed to assess residual narrowing of the descending aorta. LV mass index was increased in both groups when compared with control subjects (group I p = 0.01; group II p = 0.007). Whereas systolic performance in group I was similar to its control group, group II patients had enhanced LV systolic performance as measured by shortening fraction (p = 0.007). Multiple regression analysis of combined group I and II patients demonstrated a significant positive correlation of residual aortic narrowing with LV mass index (p = 0.01). Thus, LV mass remains increased in normotensive patients without major blood pressure gradients after repair of coarctation of the aorta in infancy or childhood. Small degrees of residual aortic narrowing were associated with increased postoperative LV mass regardless of the age at repair.

Radiologic appearance of implantable cardiac defibrillators

Since the original descriptions of the radiologic appearance of implantable cardiac defibrillators by Lurie et al. [1] and Goodman et al. [2] in 1985, rapid growth has occurred in the complexity and variety of models available. Originally, all devices were surgically placed in or on the pericardium. Now, some devices are inserted by intravascular catheters with part of the device buried in the chest wall, avoiding the need for thoracotomy. Initially, these devices were used as defibrillators for treatment of tachyarrythmia and ventricular fibrillation. Now they serve as pacemakers for both tachy- and bradyarrhythmias and can act as cardioverters or defibrillators if required. Radiologists must be familiar with the appearances of these devices as their use becomes more widespread. In this article, the electrophysiology of these devices is briefly reviewed and the typical radiologic appearances are presented along with common radiologically recognizable complications.

Early results after pediatric cardiac transplantation with triple immunosuppression therapy

Pediatric heart transplant recipients were previously reported to have higher early mortality and morbidity than do adult patients treated with triple immunosuppression therapy (steroids, azathioprine and cyclosporine). Nineteen patients (11 infants and 8 older children) underwent orthotopic transplantation using triple immunosuppression therapy. Surveillance for cellular rejection and coronary arteriopathy was performed with endomyocardial biopsy and selective coronary angiography in all patients, with continuous monitoring for hypertension and serious infection. Seventeen of 19 patients (89%; 10 infants and 7 older children) are current survivors, with a median follow-up of 29 months (range 17 to 94). There were 5 and 7 episodes of rejection in the first 12 months after transplantation in the infant and older groups, respectively, for actuarial freedom-from-rejection rates of 65% at 3 months and 54% at 12 months. Severe coronary arteriopathy was detected in 1 infant 11 months after transplantation. In the first 12 months after transplantation, there were 3 hospitalizations for infection, and 2 patients needed treatment for hypertension in the infant group, compared with 1 hospitalization for infection, and 4 patients on antihypertensives in the older group. An increased prevalence of noninfectious complications in the infant group led to significantly longer postoperative stays than in the older group (mean 27.3 vs 19.4 days; p < 0.05). The results indicate that cardiac transplantation using triple immunosuppression therapy in infants, children and adolescents is associated with a high survival rate, and low rates of rejection and serious infection.

Acute fatality following pulmonary angiography in a patient on an amiodarone regimen--a case report

A patient being treated with amiodarone experienced acute respiratory failure and death immediately following pulmonary angiography. Physicians must be aware of the potential catastrophic complication of both ionic and nonionic contrast angiography in this setting.

MR and CT diagnosis of carcinoid heart disease

This report describes findings present on magnetic resonance (MR) imaging and computed tomography (CT) in a patient with carcinoid heart disease. Major abnormalities included thickening and immobility of the tricuspid valve leaflets and disturbed flow patterns indicative of tricuspid stenosis and regurgitation demonstrated with cine MR. While echocardiography is usually the initial imaging modality in patients with carcinoid heart disease, other modalities such as MR and CT may provide correlative or supplemental information.

Pulmonary vein obstruction following single lung transplantation

Angiographic documentation after single lung transplant showed pulmonary venous obstruction due to compression by the omental pedicle. Retransplantation is described, and this complication is examined.

Increased stiffness and persistent narrowing of the aorta after successful repair of coarctation of the aorta: relationship to left ventricular mass and blood pressure at rest and with exercise

Fifteen children and adolescents who had repair of coarctation of the aorta before age 15, who were not hypertensive at rest, and who had resting arm-leg blood pressure gradients of less than 20 mm Hg underwent noninvasive evaluation of left ventricular structure and function, aortic stiffness, and residual coarctation as well as bicycle exercise testing. These results were compared with those in 15 age- and sex-matched control subjects. The mean resting age-related systolic blood pressure percentiles (63% versus 46%), transverse aortic stiffness measured by the elastic modulus (Ep) (42.1 versus 23.2 kPa), stiffness index beta (beta) (3.66 versus 2.17), echocardiographic left ventricular fractional shortening (0.42 versus 0.36), left ventricular mass index (99.3 versus 81.0 gm/m2), maximum exercise right arm systolic blood pressure (173 versus 156 mm Hg), and exercise arm-leg blood pressure gradient (35 versus 6 mm Hg) were significantly increased in the coarctectomy patients compared with controls. Univariate correlations in the coarctectomy group showed significant relationships of residual aortic narrowing with left ventricular mass index (r = 0.68, p less than 0.01) and resting systolic blood pressure percentile for age (r = 0.55, p less than 0.05). Residual aortic narrowing did not significantly correlate with aortic stiffness, resting blood pressure gradient, or exercise blood pressure gradient. Neither left ventricular mass index nor resting systolic blood pressure percentile significantly correlated with age of repair or years after repair. These results demonstrate persistent abnormalities in aortic stiffness and left ventricular mass and function after successful repair of coarctation of the aorta in childhood and adolescence.(ABSTRACT TRUNCATED AT 250 WORDS)

Fibromuscular elements of the right atrium: pseudomass at MR imaging

Results of 20 random cardiac spin-echo and cine gradient-echo magnetic resonance (MR) imaging examinations were reviewed for nodular and/or linear soft-tissue structures projecting from the right atrial wall. A nodular soft-tissue structure (mean diameter, 6 mm) isointense with myocardium was observed along the posterior atrial wall in 18 of 20 patients (90%). The structure extended between the orifices of the superior and inferior venae cavae. Linear strand-like projections originating from the structure coursed across the atrial chamber in 5 of 20 patients (25%). Similar findings were present in one patient who underwent cardiac surgery for a suspected atrial mass. The region of nodular thickening was shown histologically to represent myocyte hypertrophy and fibrosis. The nodular and linear structures correlated anatomically with the crista terminalis muscle bundle and Chiari network, respectively. These structures are frequently visualized on cardiac MR images, are of variable prominence, and may closely simulate the appearance of tumor or other cardiac masses in some patients. Awareness of the location and MR imaging features of these structures will help prevent misdiagnosis.