Chronic Thromboembolic Pulmonary Hypertension: Clinical and Imaging Evaluation.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a complication of pulmonary embolism and is an important cause of pulmonary hypertension. As a clinical entity, it is frequently underdiagnosed with prolonged diagnostic delays. This study reviews the clinical and radiographic findings associated with CTEPH to improve awareness and recognition. Strengths and limitations of multiple imaging modalities are reviewed. Accompanying images are provided to supplement the text and provide examples of important findings for the reader.

Thoracic Applications of Spectral CT Scan.

TOPIC IMPORTANCE: Thoracic imaging with CT scan has become an essential component in the evaluation of respiratory and thoracic diseases. Providers have historically used conventional single-energy CT; however, prevalence of dual-energy CT (DECT) is increasing, and as such, it is important for thoracic physicians to recognize the utility and limitations of this technology. REVIEW FINDINGS: The technical aspects of DECT are presented, and practical approaches to using DECT are provided. Imaging at multiple energy spectra allows for postprocessing of the data and the possibility of creating multiple distinct image reconstructions based on the clinical question being asked. The data regarding utility of DECT in pulmonary vascular disorders, ventilatory defects, and thoracic oncology are presented. A pictorial essay is provided to give examples of the strengths associated with DECT. SUMMARY: DECT has been most heavily studied in chronic thromboembolic pulmonary hypertension; however, it is increasingly being used across a wide spectrum of thoracic diseases. DECT combines morphologic and functional assessments in a single imaging acquisition, providing clinicians with a powerful diagnostic tool. Its role in the evaluation and treatment of thoracic diseases will likely continue to expand in the coming years as clinicians become more experienced with the technology.

A 53-Year-Old With Progressive Dyspnea.

CASE PRESENTATION: A 53-year-old woman with a history of pulmonary embolism treated with rivaroxaban came to the ED after 4 days of acutely worsening dyspnea and chest pressure. On arrival, her temperature was 36.7 °C; heart rate, 71 beats/min; BP, 98/59 mm Hg; respiratory rate, 22 breaths/min; and Spo2 95% on room air. Her WBC count was elevated at 15,770/µL; hemoglobin, 13.3 g/dL; platelets, 280,000/µL; INR (international normalized ratio), elevated at 1.66; and partial thromboplastin time, elevated at 18.8 s. Serum chemistry results were unremarkable, and pro-brain natriuretic peptide was slightly elevated at 530 pg/mL (normal, < 300 pg/mL).

Imaging of Pulmonary Hypertension: Pictorial Essay.

Pulmonary hypertension (PH) is an end result of a diverse array of complex clinical conditions that invoke hemodynamic and pathophysiological changes in the pulmonary vasculature. Many patients' symptoms begin with dyspnea on exertion for which screening tests such as chest roentgenograms and more definitive noninvasive tests such as CT scans are ordered initially. It is imperative that clinicians are cognizant of subtle clues on these imaging modalities that alert them to the possibility of PH. These clues may serve as a stepping stone towards more advanced noninvasive (echocardiogram) and invasive (right heart catheterization) testing. On the CT scan, the signs are classified into mediastinal and lung parenchymal abnormalities. In addition to suspecting the diagnosis of PH, this paper provides a pictorial essay to guide health care professionals in identifying the etiology of PH. This paper also provides concrete definitions, wherever possible, of what constitutes abnormalities in PH, such as dilated pulmonary arteries, pruning of vessels, and increased thickness of free wall of the right ventricle. The sensitivities and specificities of each sign are enumerated. The common radiographic and clinical features of many different etiologies of PH are tabulated for the convenience of the readers. Some newer imaging modalities such as dual-energy CT of the chest that hold promise for the future are also described.

A 44-Year-Old Man With Dyspnea and a Pulmonary Artery Filling Defect.

CASE PRESENTATION: A 44-year-old man with a history of coronary artery disease, type 2 diabetes mellitus, and OSA reported progressively worsening dyspnea on exertion over a 6-week period. Outpatient CT angiogram revealed a pulmonary artery filling defect. He was sent to the ED where he was started on a heparin drip for unprovoked pulmonary embolism (PE). Echocardiogram revealed normal cardiac function without evidence of right heart strain. Lower extremity ultrasound was negative for DVT. He improved symptomatically, and no risk factors for PE were identified. He was discharged on apixaban. Five weeks later, the patient returned to the ED with hemoptysis. He reported compliance with anticoagulation and improvement of his dyspnea on exertion. History remained negative for recent travel, trauma, surgery, clotting disorders, thromboembolic disease, and alcohol or drug use. He had a 60 pack-year cigarette smoking history and quit 3 months prior.