Girish S. Shroff

Pulmonary Tuberculosis: Role of Radiology in Diagnosis and Management.

Tuberculosis is a public health problem worldwide, including in the United States-particularly among immunocompromised patients and other high-risk groups. Tuberculosis manifests in active and latent forms. Active disease can occur as primary tuberculosis, developing shortly after infection, or postprimary tuberculosis, developing after a long period of latent infection. Primary tuberculosis occurs most commonly in children and immunocompromised patients, who present with lymphadenopathy, pulmonary consolidation, and pleural effusion. Postprimary tuberculosis may manifest with cavities, consolidations, and centrilobular nodules. Miliary tuberculosis refers to hematogenously disseminated disease that is more commonly seen in immunocompromised patients, who present with miliary lung nodules and multiorgan involvement. The principal means of testing for active tuberculosis is sputum analysis, including smear, culture, and nucleic acid amplification testing. Imaging findings, particularly the presence of cavitation, can affect treatment decisions, such as the duration of therapy. Latent tuberculosis is an asymptomatic infection that can lead to postprimary tuberculosis in the future. Patients who are suspected of having latent tuberculosis may undergo targeted testing with a tuberculin skin test or interferon-γ release assay. Chest radiographs are used to stratify for risk and to assess for asymptomatic active disease. Sequelae of previous tuberculosis that is now inactive manifest characteristically as fibronodular opacities in the apical and upper lung zones. Stability of radiographic findings for 6 months distinguishes inactive from active disease. Nontuberculous mycobacterial disease can sometimes mimic the findings of active tuberculosis, and laboratory confirmation is required to make the distinction. Familiarity with the imaging, clinical, and laboratory features of tuberculosis is important for diagnosis and management. ©RSNA, 2017.

CT imaging of complications of catheter ablation for atrial fibrillation.

The complication rate following radiofrequency catheter ablation for atrial fibrillation is low (<5%). Complications include pericardial effusion, cardiac tamponade, pulmonary vein stenosis, oesophageal ulceration or perforation, atrio-oesophageal fistula formation, stroke/transient ischaemic attack, phrenic nerve injury, haematoma at the puncture site, and femoral arteriovenous fistula. Among available imaging tools, computed tomography (CT) can be very useful in diagnosing complications of the procedure, particularly in the subacute and delayed stages after ablation. This review illustrates CT imaging of several of the common and uncommon complications of radiofrequency catheter ablation.

Differentiating pericardial recesses from mediastinal adenopathy: potential pitfalls in oncological imaging.

In oncological imaging, staging with computed tomography (CT) is widely used to determine treatment. Misinterpretation of fluid in pericardial recesses as mediastinal adenopathy can lead to inaccurate clinical staging and inappropriate management. In this review, we describe normal pericardial anatomy and illustrate imaging features to differentiate fluid in pericardial sinuses and recesses from mediastinal adenopathy.

Targeted Therapy and Immunotherapy in the Treatment of Non–Small Cell Lung Cancer

The treatment strategy in advanced non-small cell lung cancer (NSCLC) has evolved from empirical chemotherapy to a personalized approach based on histology and molecular markers of primary tumors. Targeted therapies are directed at the products of oncogenic driver mutations. Immunotherapy facilitates the recognition of cancer as foreign by the host immune system, stimulates the immune system, and alleviates the inhibition that allows the growth and spread of cancer cells. The authors describes the role of targeted therapy and immunotherapy in the treatment of NSCLC, patterns of disease present on imaging studies, and immune-related adverse events encountered with immunotherapy.

Magnetic resonance imaging safety in cardiothoracic imaging

Patient safety is a priority for patients undergoing magnetic resonance imaging (MRI). This article reviews MRI safety issues related to devices, pharmacologic stress agents, contrast agents, anesthesia, and external equipment, focusing on cardiothoracic MRI.

Cement Pulmonary Embolism After Percutaneous Vertebral Augmentation in a Patient With Pathologic Lumbar Fracture From Metastatic Breast Cancer.

A 51-year-old female patient with an oncologic history of metastatic right breast cancer, status post treatment including neoadjuvant chemotherapy (paclitaxel followed by 5-fluorouracil, adriamycin, and cyclophosphamide), right total mastectomy and axillary node dissection, postoperative adjuvant radiation therapy, and hormonal therapy, presented to the emergency center complaining of progressively worsening lumbar axial pain. Workup revealed extensive thoracolumbar vertebral metastatic disease and a first lumbar vertebra pathologic fracture with 50% compression and a retropulsed fragment causing effacement of the cauda equina, among other findings.

Vein of Labbe thrombosis by CT and MRI

A 66-year-old man with tongue carcinoma presented to the emergency room (ER) with decreased oral intake for one week. In the ER, he experienced a generalised seizure. Neurological examination was non-focal. Noncontrast CT brain revealed bandlike high attenuation along the course of the left vein of Labbe (figure 1). Findings suggested vein of Labbe thrombosis and were confirmed with MRI and magnetic resonance venography (MRV) (figure 2). Figure 1 Noncontrast CT brain (cephalad to caudad in A–D) revealing bandlike high attenuation suggestive of thrombus along the expected course of the left vein of Labbe (arrows). Figure 2 MRI and magnetic resonance venography of vein of Labbe thrombosis. An extra-axial band corresponding to the thrombosed vein of Labbe is isointense on T1-weighted imaging …

Targeted Therapy and Imaging Findings

Non–small cell lung cancer (NSCLC) is usually diagnosed when it is not amenable to curative surgery or radiation. Many of these patients are candidates for systemic therapy. Median survival is only approximately 10 months, and, accordingly, treatment in advanced NSCLC is evolving toward a more personalized approach with the identification of genetic abnormalities based on biomarkers. For example, gene mutations in EGFR (epidermal growth factor receptor) and ALK (anaplastic lymphoma kinase) lead to a cascade of pathways resulting in uncontrolled growth, proliferation, and survival of tumor cells. Targeted therapies are aimed at the products of these mutated genes and include agents such as erlotinib and gefitinib (in EGFR-mutant NSCLC) or crizotinib (in ALK-positive NSCLC). Antiangiogenesis agents such as bevacizumab are another category of targeted therapy that inhibits vascular endothelial growth factors. The imaging characteristics of advanced NSCLC with genetic abnormalities, the evolution of targeted therapies and their imaging manifestations will be discussed.

Challenges in Interpretation of Staging PET/CT in Thoracic Malignancies

18F-fluorodeoxryglucose (18F-FDG) PET/CT imaging is routinely performed in the evaluation of patients with known or suspected thoracic malignancy. Indications for its use include staging of malignancy, assessment of response to therapy, evaluation of suspected disease recurrence, and evaluation of a solitary pulmonary nodule. In this article, we will discuss specific technical artifacts and also review potential pitfalls in the interpretation of PET/CT in thoracic malignancies including normal variations in physiologic uptake of FDG, benign conditions (such as infection, inflammation, posttreatment changes, and iatrogenic factors) that can result in increased FDG uptake, and malignancies that demonstrate scarce to no FDG uptake.

Cement pulmonary embolism

A 72-year-old man with a history of vertebroplasty 3 months ago presented with fever. Chest radiograph revealed thin radioopaque linear and branching opacities (arrows, Figure 1A). Findings were compatible with cement pulmonary embolism. Abdominal radiograph revealed evidence of prior vertebroplasty (arrows, Figure 1B). Percutaneous vertebroplasty and balloon kyphoplasty are procedures performed to treat painful vertebral fractures. These procedures involve the injection of polymethylmethacrylate (PMMA) into the vertebral body. Cement pulmonary embolism is a potential complication of these procedures with incidence rates ranging from 3.5% to 23%. Cement pulmonary embolism results from the leakage of PMMA into the perivertebral veins. The PMMA eventually travels from the venous system into the pulmonary arteries. In most cases, cement pulmonary emboli are asymptomatic and discovered incidentally on postoperative chest radiographs. Treatment depends on the presence of symptoms and may include clinical observation, anticoagulation, or in rare instances, surgical removal. The patient in this case was not treated because he was asymptomatic.