The role of imaging in pulmonary hypertension

Abstract

Pulmonary hypertension (PH) is a debilitating and potentially life threatening condition in which increased pressure in the pulmonary arteries may result from a variety of pathological processes. These can include disease primarily involving the pulmonary vasculature, but more commonly PH may result from left-sided heart disease, including valvular heart disease. Chronic thromboembolic pulmonary hypertension (CTEPH) is an important disease to identify because it may be amenable to surgical pulmonary artery endarterectomy or balloon pulmonary angioplasty. Parenchymal lung diseases are also widespread in the community. Any of these disease processes may result in adverse remodeling of the right ventricle and progressive right heart (RH) failure as a common final pathway. Because of the breadth of pathological processes which cause PH, multiple imaging modalities play vital roles in ensuring accurate diagnosis and classification, which will lead to application of the most appropriate therapy. Multimodality imaging may also provide important prognostic information and has a role in the assessment of response to therapies which ultimately dictate clinical outcomes. This review provides an overview of the wide variety of established imaging techniques currently in use, but also examines many of the novel imaging techniques which may be increasingly utilized in the future to guide comprehensive care of patients with PH.

Keywords: Pulmonary hypertension (PH); cardiac magnetic resonance; computed tomography; echocardiography; multimodality imaging; right ventricle.

Figure 1

AP frontal radiograph in a 55-year-old female with pulmonary arterial hypertension demonstrating markedly prominent pulmonary arteries (arrows) and peripheral arterial pruning.

Figure 2

PA chest radiograph in a 62-year-old male demonstrating extensive middle and lower zone pulmonary fibrosis.

Figure 3

Estimation of pulmonary artery systolic pressure from the peak tricuspid regurgitation continuous wave Doppler velocity (A,B) and from the size of the inferior vena cava and its response to a sniff (C,D). The IVC size fails to decrease with a sniff indicting elevated right atrial pressure.

Figure 4

Doppler features supporting the presence of pulmonary hypertension (PH). A short pulmonary artery acceleration time (PAAT) <90 ms and the presence of mid-systolic notching (arrow) of the pulmonary valve pulsed wave Doppler signal (A) suggest PH. Using a CW Doppler recording of the pulmonary regurgitation (PR) signal, the PR Vmax can be used to estimate the mean pulmonary artery (PA) pressure and the PR diastolic pressure estimated from the end-diastolic velocity (B).

Figure 5

Parasternal short axis view of the heart showing a dilated right ventricle (RV) and a flattened interventricular septum (IVS, arrows) resulting in a D-shaped left ventricle (LV) due to RV pressure overload.

Figure 6

Mitral valve disease may cause pulmonary hypertension. (A) Transthoracic echocardiogram showing rheumatic mitral stenosis including a rendered 3-d image with diastolic doming of the anterior mitral valve (MV) leaflet; (B) severe mitral regurgitation (MR). LV, left ventricle; LA left atrium; plax, parasternal long axis; psax, parasternal short axis.

Figure 7

Assessment of right heart size by echocardiography. (A) Measurement of right ventricular diameter from an apical 4-chamber view; (B) measurement of right atrial area from an apical 4-chamber view. RV, right ventricle; RA, right atrium; LV, left ventricle; LA, left atrium.

Figure 8

Quantification right heart systolic function using fractional area change (FAC). The area of the right ventricle is measured at end-diastole (A) and end-systole (B) and the percentage area change is the FAC. FAC is decreased in this example. RV, right ventricle; LV, left ventricle.

Figure 9

Measurement of tricuspid annular plane systolic excursion (TAPSE) in a normal subject (A) and in a patient with pulmonary hypertension (B) where TAPSE is reduced.

Figure 10

Quantification of right ventricular (RV) systolic function using RVS’ in a normal subject where RVS’ =18.2 cm/s (A) and in a patient with impaired RV function due to pulmonary hypertension with reduced RVS’ of 5.8 cm/s (B).

Figure 11

Measurement of right ventricular (RV) global longitudinal strain using speckle-tracking. Panel (A) shows a normal subject. The patient in (B) has pulmonary hypertension with reduced RV global strain of 15.4%.

Figure 12

CT scan of the chest in a 71-year-old male with marked pulmonary hypertension on the background of COPD and previous pulmonary emboli. The dilated main pulmonary artery (MPA) is larger than the adjacent ascending aorta (Ao).

Figure 13

Coronal reconstruction (A) and axial slice (B) from a CT scan of the chest showing changes of interstitial lung disease. Sub-pleural and predominantly basal reticulation and mild traction bronchiectasis with ground glass opacity suggestive of pulmonary fibrosis in a 61-year-old female.

Figure 14

Ventilation-perfusion lung scan with multiple unmatched perfusion defects consistent with chronic thromboembolic pulmonary hypertension (CTEPH) in a 71-year-old male.

Figure 15

Cardiac SSFP images on a patient with chronic thromboembolic pulmonary hypertension (CTEPH). The upper panels shows short axis views at end-diastole, end-systole and in the early-left ventricular (LV) diastolic filling phase. The lower panels show 4-chamber views with the position of the short axis planes shown. The right ventricle (RV) and right atrium are dilated. The short axis views demonstrate with a dilated right ventricle and marked flattening of the interventicular septum at end-systole producing a D-shaped left ventricle due to RV pressure overload. In the early-LV filling phase there is additional septal shift with increased pressure gradient between the RV and the LV causing reversal of the normal septal curvature. A small pericardial effusion is also noted. Images courtesy of Dr Guido Classsen.