Gautham P. Reddy

Clinical evaluation of aortic coarctation with 4D flow MR imaging

To show that 4D Flow is a clinically viable tool for evaluation of collateral blood flow and demonstration of distorted blood flow patterns in patients with treated and untreated aortic coarctation.

Carotid Intima-Media Thickness Among Human Immunodeficiency Virus–Infected Patients Without Coronary Calcium

Subjects infected with human immunodeficiency virus (HIV) have increased risk for atherosclerosis. Carotid artery intima-media thickness (IMT) assessed using ultrasound and coronary artery calcium (CAC) detected using computed tomography predict cardiovascular risk in the general population; however, their usefulness and comparability in patients with HIV are less well defined. The purpose of this study was to compare IMT and CAC in the detection of atherosclerosis in subjects with HIV. CAC and IMT were measured in 253 HIV-infected and 58 uninfected adults. Associations among HIV-related factors, traditional risk factors, and CAC and IMT were evaluated. The distribution of IMT among subjects with and without CAC was compared. Among the patients with HIV, 37% had detectable CAC compared to 28% of controls (p = 0.19); 16% of the patients with HIV had CAC >100 compared to 5% of controls (p = 0.03). With either detectable or undetectable CAC, HIV-infected subjects had higher IMT compared to controls (1.02 ± 0.34 vs 0.78 ± 0.12 mm, p <0.0001), even after adjustment for traditional risk factors. Among those with undetectable CAC, 34% of patients with HIV had markedly increased IMT (≥1 mm) compared to no controls (p <0.0001). HIV-related factors were associated with IMT but not with CAC. In conclusion, patients with HIV and controls had similar rates of detectable CAC, while absolute CAC scores were modestly higher in the HIV group. Conversely, carotid IMT detected advanced subclinical atherosclerosis in patients with HIV even in the absence of CAC. Thus, with HIV, IMT is associated with disease-related factors and may be a more sensitive indicator of subclinical atherosclerosis than CAC.

Digital Tomosynthesis of the Chest: Current and Emerging Applications

Digital tomosynthesis (DTS) of the chest is a technique whose basic components are similar to those of digital radiography, but that also provides some of the benefits of computed tomography (CT). The major advantages of DTS over conventional chest radiography are improved visibility of the pulmonary parenchyma and depiction of abnormalities such as pulmonary nodules. Calcifications, vessels, airways, and chest wall abnormalities are also much more readily visualized at DTS than at chest radiography. DTS could potentially be combined with chest radiography to follow up known nodules, confirm or rule out suspected nodules seen at radiography, or evaluate individuals who are at high risk for lung cancer or pulmonary metastases. DTS generates coronal slices through the chest whose resolution is superior to that of coronal reconstructed CT images, but it is limited by its suboptimal depth resolution and susceptibility to motion; consequently, potential pitfalls in recognizing lesions adjacent to the pleura, diaphragm, central vessels, and mediastinum can occur. However, the radiation dose and projected cost of chest DTS are lower than those of standard chest CT. Besides pulmonary nodule detection, specific applications of DTS that are under investigation include evaluation of pulmonary tuberculous and nontuberculous mycobacterial disease, cystic fibrosis, interstitial lung disease, and asbestos-related thoracic diseases. A basic understanding of chest DTS and of the emerging applications of this technique can prove useful to the radiologist. Online supplemental material is available for this article.

ACR Appropriateness Criteria® screening for pulmonary metastases.

Screening for pulmonary metastatic disease is an important step for staging a patient with a known or recently discovered malignancy. Here we present our recommendations for screening for metastatic disease based on recommendations from the literature and experiences of pulmonary radiologists. In short, chest computed tomographic (CT) screening is the most appropriate tool for evaluation of pulmonary metastasis in the majority of cases. Chest computed tomographic screening is also recommended for follow-up and to determine response to therapy. Other modalities such as chest radiography, magnetic resonance imaging, and scintigraphy will also be discussed. Please note that this study is a summary of the complete version of this topic, which is available on the ACR website at www.acr.org. Practitioners are encouraged to refer to the complete version.

ACR appropriateness criteria routine chest radiographs in intensive care unit patients.

Daily routine chest radiographs in the intensive care unit (ICU) have been a tradition for many years. Anecdotal reports of misplacement of life support items, acute lung processes, and extra pulmonary air collections in a small number of patients served as a justification for routine chest radiographs in the ICU. Having analyzed this practice, the ACR Appropriateness Criteria Expert Panel on Thoracic Imaging has made the following recommendations: • When monitoring a stable patient or a patient on mechanical ventilation in the ICU, a portable chest radiograph is appropriate for clinical indications only. • It is appropriate to obtain a chest radiograph after placement of an endotracheal tube, central venous line, Swan-Ganz catheter, nasogastric tube, feeding tube, or chest tube. 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. The strongest data contributing to these recommendations were derived from a meta-analysis of 8 trials comprising 7,078 ICU patients by Oba and Zaza [1].

Radiology of the Heart

The chest radiograph is the first imaging study performed in patients suspected of having cardiac disease. This chapter discusses the role of the chest radiograph in the diagnosis of cardiac disease in adults, with an emphasis on both normal cardiovascular anatomy and pathology in a variety of diseases. Cross-sectional imaging is correlated with plain film images to illustrate important anatomic points. Thorough knowledge of mediastinal interfaces and the cardiac borders will help to determine if pathology is present. There are many frequently occurring cardiovascular conditions with specific and often diagnostic imaging findings on the plain chest radiograph. The conditions that will be discussed include aortic stenosis and insufficiency, mitral stenosis and acute mitral regurgitation, pericardial calcification suggesting constriction, and the plain film alterations found in atrial septal defect and other intracardiac defects.

Tumorlike Conditions of the Pleura

Tumorlike conditions of the pleura are rare, but diagnosis is facilitated by recognizing certain imaging patterns and interpreting them in the clinical context. A tumorlike condition of the pleura is any nonneoplastic lesion of the pleura itself, or within the pleural space, that resembles a tumor. An approach to diagnosis of the tumorlike conditions of the pleura is provided, and these conditions are grouped into focal or diffuse conditions, with an emphasis on specific imaging features. Focal tumorlike conditions of the pleura include pleural plaque, thoracic splenosis, thoracic endometriosis causing catamenial pneumothorax, and pseudotumor caused by pleural effusion. Thoracic splenosis should be considered in a patient who has a healed left lower rib fracture, an absent spleen, and left lower pleural nodules. Thoracic endometriosis with catamenial pneumothorax should be considered in a woman of childbearing age who presents with right scapular pain and recurrent pneumothorax occurring at or around the onset of menses. Extrapleural hematoma is a nonpleural mimic of pleural tumor and shares some imaging features with focal tumorlike conditions of the pleura, despite residing in the extrapleural space. Diffuse tumorlike conditions of the pleura include diffuse pleural thickening and rare conditions such as Erdheim-Chester disease and diffuse pulmonary lymphangiomatosis. Erdheim-Chester disease should be considered when diffuse pleural thickening occurs with a perirenal soft-tissue halo or distal femoral sclerosis. Diffuse pulmonary lymphangiomatosis should be considered when findings include diffuse pleural thickening, interlobular septal and peribronchovascular interstitial thickening, and mediastinal fat infiltration limited to the thorax and when these findings persist despite diuretic therapy.

Cardiac Complications of Oncologic Therapy

As survival rates continue to increase for patients with childhood and adult malignancies, imaging utilization in these patients will likely increase substantially. It is important to detect disease recurrence and to recognize the potential complications that occur after treatment with oncologic medications and therapeutic radiation. The most common cardiotoxic side effect of the anthracycline drug class is a dose-dependent decline in ejection fraction, which may result in dilated cardiomyopathy. Multiple-uptake gated acquisition (MUGA) scanning plays an important role in diagnosis of this subclinical cardiac dysfunction. Other less common cardiotoxic side effects of chemotherapeutic medications include arrhythmia, myocarditis, coronary artery disease, tamponade, pericarditis, and pericardial effusion. Radiation therapy can also lead to cardiotoxicity when the heart or pericardium is included in the radiation portal. Radiation-induced conditions include pericardial disease, coronary artery disease, valvular disease, and cardiomyopathy. Many of these side effects are asymptomatic until late in the course of the disease. With imaging, these pathologic conditions can often be diagnosed before symptom onset, which may allow early intervention. Radiologists should be familiar with the current knowledge and pathophysiology regarding cardiac complications related to chemotherapy and radiation therapy of malignant neoplasms and the appearances of treatment-related cardiotoxicity that can be found at radiography, nuclear medicine examinations, and cross-sectional imaging. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.336125005/-/DC1.

ACR Appropriateness Criteria® noninvasive clinical staging of bronchogenic carcinoma.

In order to appropriately manage patients with lung cancer, it is necessary to properly stage the tumor. The ACR Appropriateness Criteria is designed to provide an overview of the value of different imaging techniques in the non-invasive staging of lung cancer and allow for the rational selection of imaging studies to arrive at the appropriate clinical stage.

Cardiovascular Risk Factors and Coronary Atherosclerosis in Retired National Football League Players

A high prevalence of obesity exists in National Football League (NFL) players as determined by body mass index (BMI). It is not established whether increased BMI is associated with a greater prevalence of cardiovascular (CV) risk factors or coronary atherosclerosis in former NFL players than in nonathletes. This study compared CV risk factors and coronary atherosclerosis in retired NFL players to 2 groups of community controls, the population-based Dallas Heart Study and the preventive medicine cohort, the Aerobics Center Longitudinal Study. Retired NFL players (n = 201) were matched for ethnicity, age, and BMI (Aerobics Center Longitudinal Study, age only). CV risk factors were assessed by survey and screening visit. Coronary atherosclerosis was measured by computed tomography as coronary artery calcium (CAC). Compared to population-based controls, retired NFL players had a significantly lower prevalence of diabetes, hypertension, sedentary lifestyle, and metabolic syndrome, yet a higher prevalence of impaired fasting glucose and hyperlipidemia. However, there was no significant difference in the prevalence of detectable CAC (46% vs 48.3%, p = 0.69) or distribution of CAC (0 to 10, 10 to 100, 100 to 400, > or =400, p = 0.11). Comparing retired NFL players to the physically active preventive medicine controls, there was no difference in the amount of CAC. In retired NFL players, age and hyperlipidemia, not body size, were the most significant predictors of CAC. In conclusion, despite their large body size, retired NFL players do not have a greater prevalence of CV risk factors or amount of CAC than community controls.