Published online Jun 28, 2014. doi: 10.4329/wjr.v6.i6.230
Revised: April 22, 2014
Accepted: May 15, 2014
Published online: June 28, 2014
Hydrostatic pulmonary edema is as an abnormal increase in extravascular water secondary to elevated pressure in the pulmonary circulation, due to congestive heart failure or intravascular volume overload. Diagnosis of hydrostatic pulmonary edema is usually based on clinical signs associated to conventional radiography findings. Interpretation of radiologic signs of cardiogenic pulmonary edema are often questionable and subject. For a bedside prompt evaluation, lung ultrasound (LUS) may assess pulmonary congestion through the evaluation of vertical reverberation artifacts, known as B-lines. These artifacts are related to multiple minimal acoustic interfaces between small water-rich structures and alveolar air, as it happens in case of thickened interlobular septa due to increase of extravascular lung water. The number, diffusion and intensity of B lines correlates with both the radiologic and invasive estimate of extravascular lung water. The integration of conventional chest radiograph with LUS can be very helpful to obtain the correct diagnosis. Computed tomography (CT) is of limited use in the work up of cardiogenic pulmonary edema, due to its high cost, little use in the emergencies and radiation exposure. However, a deep knowledge of CT signs of pulmonary edema is crucial when other similar pulmonary conditions may occasionally be in the differential diagnosis.
Core tip: Acute decompensated heart failure (ADHF) is a frequent emergency condition that represents a diagnostic challenge for the emergency physicians. Imaging has a fundamental role in the diagnosis of heart failure, but the efficacy of the diagnostic process is highly dependent from the ability to integrate information drawn from lung ultrasound (LUS), chest radiography and computed tomography (CT). Chest radiography and LUS are the most used diagnostic tools: the first one combining relative low cost with the panoramic view that allows exclusion of many pulmonary conditions that comes into the differential diagnosis; otherwise the second one has higher sensitivity in the diagnosis of the early signs of pulmonary congestion and permit to perform the examination at bedside during the first clinical approach. CT scan is the best method to have a panoramic thoracic view and CT scan is a powerful method but it has many limitations due to costs, availability in emergency situations and relatively high radiation exposure. The modern clinician and radiologist should be aware of the potential and limitations of these diagnostic tools and be prepared to integrate information derived from a correct use of ultrasound, conventional radiology and CT.