Effectiveness of chest radiography, lung ultrasound and thoracic computed tomography in the diagnosis of congestive heart failure

Abstract

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.

Keywords: Dyspnea; Emergency department; Heart Failure/ultrasonography; Heart failure/complications; Interstitial/ultrasonography; Lung diseases; Pulmonary edema/radiography; Pulmonary edema/ultrasonography; Ultrasonography.

Figures

Figure 1

Posterior-anterior chest X-ray in a patient with congestive heart failure and interstitial pulmonary edema. In the figure are shown radiographic signs that suggest interstitial pulmonary edema including enlarged and loss of definition of large pulmonary vessels, both Kerley's A and Kerley's B lines associated with cardiomegaly.

Figure 2

Posterior-anterior chest X-ray demonstrating enlargement of atrial and left ventricles, with redistribution of lung circulation from bases to apex suggestive to pulmonary congestion (A), note the blood vessels are more prominent in the upper lung fields compared to the lung bases, just the opposite of normal (B).

Figure 3

Supine radiogram in a patient with cardiogenic alveolar edema. Note that the vascular perihilar structures are not defined because of the presence of confluent peripheral and gravitational consolidations, with large pleural effusion. Cardiomegaly is also present.

Figure 4

Antero-posterior chest radiograph with asymmetric pulmonary edema with grade 3 mitral insufficiency shows pulmonary edema predominantly within the right upper lobe.

Figure 5

Lung ultrasound scan showing multiple B-lines from a case of cardiogenic pulmonary oedema. When a similar pattern is visualised on multiple locations in the anterior and lateral chest, it is diagnostic of the interstitial syndrome.

Figure 6

A typical sonographic pattern of diffuse alveolar-interstitial syndrome (left side) and corresponding chest radiograph (right side) in a case of acute cardiogenic pulmonary oedema. In the sonographic images on either side of the radiogram, the presence of multiple adjacent comet-tail artefacts (at least three per scan and in all chest areas examined) can be easily distinguished. The images illustrate the sonographic B+ pattern corresponding to the radiological finding of pulmonary oedema.

Figure 7

Computed tomography scan through lower lobes shows, limited areas of ground-glass opacity, with thickening of major fissures reflecting subpleural interstitial edema. Is also present interlobular septal and peribronchovascular interstitial thickening.

Figure 8

Computed tomography scan through aortic arch and pulmonary arteries planes shows ground-glass opacity with geographic distribution and partial sparing of the lung periphery. Thickening of interlobular septa and sub-pleural edema and bilateral pleural effusion with passive atelectasis of lower lobes is also present.