Prognostic value of pulmonary blood volume by first-pass contrast-enhanced CMR in heart failure outpatients: the PROVE-HF study.

Aims: Pulmonary blood volume (PBV) is a novel clinical application of cardiovascular magnetic resonance (CMR) imaging for the quantitative grading of haemodynamic congestion. In this study, we aimed to assess the prognostic value of PBV in a cohort of outpatients with chronic heart failure (HF). Methods and results: One hundred and twelve consecutive patients (91 men, 67 ± 12 years) and 53 age- and sex-matched healthy controls underwent echocardiography and contrast-enhanced CMR. PBV was calculated as the product of stroke volume and the number of cardiac cycles for an intravenous bolus of gadolinium contrast to pass through the pulmonary circulation determined by first-pass perfusion imaging. Compared with healthy controls, HF outpatients showed significantly higher PBV index (PBVI, 308 ± 92 vs. 373 ± 175, mL/m2, P = 0.012) and pulmonary transit time (6.8 ± 1.8 vs. 9.5 ± 4 s, P ≤0.001). During a median follow-up of 26 ± 17 months, 27 patients (24%) reached the composite end point of cardiovascular death, HF hospitalization, or sustained ventricular arrhythmias/appropriate implantable cardioverter-defibrillator intervention. Using a cut-off point of PBVI >492 mL/m2, corresponding to two standard deviations above the mean of healthy controls, event-free survival was significantly lower in patients with higher PBVI (P < 0.001). At multivariable-adjusted Cox regression analysis, PBVI was an independent predictor of the composite cardiovascular end point (per 10% increase hazard ratio 1.31, 95% confidence interval: 1.02-1.69, P = 0.03). Conclusions: PBVI is a novel application of perfusion CMR potentially useful to quantitatively determine haemodynamic congestion as a surrogate marker of left ventricular diastolic dysfunction. PBVI might prove to be helpful in stratifying the prognosis of asymptomatic or mildly symptomatic patients with left ventricular dysfunction.

Radiographic evaluation of mediastinal lines as a diagnostic approach to occult or subtle mediastinal abnormalities.

The mediastinal lines visible at conventional radiography represent the interfaces between the mediastinum and adjacent lung parenchyma. Preservation, obliteration, thickening and distortion of these lines represent the key to detecting and localising mediastinal abnormalities on chest radiographs. The learning objectives of this review are to: illustrate radiographic anatomy of the mediastinum with particular attention to mediastinal lines; describe radiographic signs that allow identification of mediastinal abnormalities that are difficult to detect on conventional chest radiographs; describe findings that help localise abnormalities in the anterior, middle or posterior mediastinum. The anterior junction line obliteration, the hilum overlay sign, the preservation of the posterior mediastinal lines and the silhouette sign with the right cardiac border are radiographic signs that allow identification and localisation of anterior mediastinal lesions. Widening of the right paratracheal stripe, distortion of the azygo-oesophageal recess and the convex border of the aortopulmonary window indicate the presence of a middle mediastinal abnormality. Thickening, distortion or disruption of paraortic and paraspinal lines and posterior junction line obliteration are caused by posterior mediastinal lesions. Knowledge of normal radiographic mediastinal anatomy and mediastinal lines is crucial to identifying subtle mediastinal abnormalities that can be easily missed on conventional radiography. Moreover, this approach allows identification of the involved mediastinal compartment on chest radiographs, thereby directing the most appropriate further diagnostic workup.