Editorial for “Evaluation of Dynamic Contrast‐Enhanced MRI Measures of Lung Congestion and Endothelial Permeability in Heart Failure: A Prospective Method Validation Study”

Patients with heart failure (HF) commonly develop pulmonary congestion (edema), which may contribute to worsening pulmonary vascular disease and biventricular HF. In both acute and chronic HF, individuals presenting pulmonary congestion in addition are at higher risk for hospitalization and even death. Moreover, dyspnea is a frequent consequence of lung edema, limiting patients’ activities and urging them to seek medical care. Addressing pulmonary congestion therapeutically in HF patients is, therefore, of great relevance. It is still common practice in this context to base therapy guidance on patientreported symptom improvement and auscultation, as well as on other measurements of treatment effects such as urine output or weight loss. The challenge of this approach is that overor under-dosing can easily happen. While syncope or worsening renal function may happen due to overdosing, underdosing with associated residual congestion may lead to early hospital readmission. A good assessment of pulmonary edema is thus essential for an improved decision-making regarding therapies for this condition. Physical examination and chest radiography were traditionally used to assess pulmonary congestion. More recently, lung ultrasound has been identified as a sensitive and semiquantitative tool for the assessment of pulmonary congestion in HF. Hyperechoic artifacts arising from the pleural surface known as B-lines appearing vertically are detected in several zones of the chest. Quantification is achieved by summing the number of B-lines across prespecified chest zones, or by a score-based approach, in which a chest zone is considered “positive” if a certain number of B-lines are seen. Of importance, lung ultrasound measures change in response to HF therapy. In the present issue of the Journal of Magnetic Resonance Imaging, the application of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to examine pulmonary congestion in HF patients is described. By assessing the plasma volume fraction (vp), the interstitial volume fraction (ve), and the transfer constant Ktrans between vp and ve, DCE-MRI based on the use of gadolinium-based contrast agents may enable discrimination of intravascular and extravascular water components, thus providing potential to quantify mild stages of pulmonary edema. Despite the fact that the technique has been used earlier to assess transpulmonary circulation (pulmonary transit time) in healthy volunteers and in HF patients, its application aiming to quantify lung congestion in HF is new and deserves attention. The main finding of the present study was an increased fraction of fluid volume in the interstitial lung space of individuals affected by HF compared to healthy controls, a result that might indicate a redistribution of lung water to the interstitial compartment. This publication could open the avenue for new studies, as the authors themselves point out. In view of the encouraging results from this validation study, it would be important to verify the suitability of DCE-MRI for a more broad application in the assessment of pulmonary congestion in HF. Careful comparison to lung ultrasound and clinical examinations in a larger cohort of HF patients would be essential in this endeavor. It would also be important to analyze how the DCE-MRI parameters change upon treatment. Moreover, considering that gadolinium-based contrast agents have been associated with different types of toxicity, a benefit/risk analysis is warranted especially if repeated DCE-MRI assessments are envisaged. Overall, it is the hope that HF patients will benefit from such imaging analyses in order to choose appropriate therapy regimens for pulmonary congestion.