A Clinical Approach to Multimodality Imaging in Pulmonary Hypertension

Abstract

Pulmonary hypertension (PH) is a clinical condition characterized by progressive elevations in mean pulmonary artery pressures and right ventricular dysfunction, associated with significant morbidity and mortality. For resting PH to develop, ~50–70% of the pulmonary vasculature must be affected, suggesting that even mild hemodynamic abnormalities are representative of advanced pulmonary vascular disease. The definitive diagnosis of PH is based upon hemodynamics measured by right heart catheterization; however this is an invasive and resource intense study. Early identification of pulmonary vascular disease offers the opportunity to improve outcomes by instituting therapies that slow, reverse, or potentially prevent this devastating disease. Multimodality imaging, including non-invasive modalities such as echocardiography, computed tomography, ventilation perfusion scans, and cardiac magnetic resonance imaging, has emerged as an integral tool for screening, classifying, prognosticating, and monitoring response to therapy in PH. Additionally, novel imaging modalities such as echocardiographic strain imaging, 3D echocardiography, dual energy CT, FDG-PET, and 4D flow MRI are actively being investigated to assess the severity of right ventricular dysfunction in PH. In this review, we will describe the utility and clinical application of multimodality imaging techniques across PH subtypes as it pertains to screening and monitoring of PH.

Sarcoidosis-Associated Pulmonary Hypertension

“…Pulmonary angiography will help to reach this diagnosis, but dual-energy CT (DECT) [64,71,72] provides more information, including morphological information on the vasculature and functional information on perfusion. Primarily used to replace V/Q scanning, which does not allow any evaluation of the lung parenchyma nor mediastinal lymph nodes, it has also been investigated as a screening tool for pulmonary hypertension whatever its cause [73]. Its value in the clinical work-up in this context, and particularly in SAPH, is still undetermined.…”

Pulmonary hypertension in interstitial lung disease: an area of unmet clinical need

“…[26] Multimodality imaging such as echocardiography, computed tomography, and ventilation perfusion scans has emerged as an integral tool for screening, classifying and prognosticating in PH. [27] Clinical symptoms and signs tend to be nonspecific, until stigmata of right heart failure become apparent in later stages of the disease. Therefore, a high index of suspicion is needed and screening for PH should be considered in patients with ILD where the severity of symptoms appears to be disproportionate to the parenchymal lung disease.…”

Pulmonary Hypertension in Chronic Lung Diseases: What Role Do Radiologists Play?

“…Due to its high spatial resolution, wide field-of-view, and capability of processing highquality multi-planar reconstructions (MPRs) and maximum intensity projections (MIPs), CT allows the recognition of PH-induced anatomical changes in pulmonary vasculature up to the peripheral branches as well as the identification of possible etiologies of PH [2]. Particularly, high-resolution CT (HRCT) techniques facilitate the evaluation of lung parenchyma and the diagnosis of PH secondary to lung disease (group 3 and group 5 PH), while the use of contrast medium in CTPA is essential if chronic pulmonary embolism is suspected as a cause of PH (Group 4 PH) [11].…”

“…Dual-energy CT (DECT) has also been investigated to measure lung perfusion qualitatively and quantitatively [11]. DECT provides morphological information on the vas-culature and functional information on perfusion by quantifying the iodine amount in the pulmonary vasculature, which can serve as a surrogate for pulmonary perfusion [12].…”

“…DECT provides morphological information on the vas-culature and functional information on perfusion by quantifying the iodine amount in the pulmonary vasculature, which can serve as a surrogate for pulmonary perfusion [12]. DECT is primarily used to replace V/Q scanning, which is not widely available, in the diagnosis of chronic thromboembolic PH (CTEPH), but it has also been investigated as a screening tool for PH brought on by any cause [11]. Nevertheless, the value of DECT in the clinical diagnostic work-up of patients with PH is still undetermined [1].…”