Rationale: Smoking-related microvascular loss causes end-organ damage in the kidneys, heart, and brain. Basic research suggests a similar process in the lungs, but no large studies have assessed pulmonary microvascular blood flow (PMBF) in early chronic lung disease.Objectives: To investigate whether PMBF is reduced in mild as well as more severe chronic obstructive pulmonary disease (COPD) and emphysema.Methods: PMBF was measured using gadolinium-enhanced magnetic resonance imaging (MRI) among smokers with COPD and control subjects age 50 to 79 years without clinical cardiovascular disease. COPD severity was defined by standard criteria. Emphysema on computed tomography (CT) was defined by the percentage of lung regions below 2950 Hounsfield units (2950 HU) and by radiologists using a standard protocol. We adjusted for potential confounders, including smoking, oxygenation, and left ventricular cardiac output.Measurements and Main Results: Among 144 participants, PMBF was reduced by 30% in mild COPD, by 29% in moderate COPD, and by 52% in severe COPD (all P , 0.01 vs. control subjects). PMBF was reduced with greater percentage emphysema 2950HU and radiologist-defined emphysema, particularly panlobular and centrilobular emphysema (all P < 0.01). Registration of MRI and CT images revealed that PMBF was reduced in mild COPD in both nonemphysematous and emphysematous lung regions. Associations for PMBF were independent of measures of small airways disease on CT and gas trapping largely because emphysema and small airways disease occurred in different smokers.Conclusions: PMBF was reduced in mild COPD, including in regions of lung without frank emphysema, and may represent a distinct pathological process from small airways disease. PMBF may provide an imaging biomarker for therapeutic strategies targeting the pulmonary microvasculature.
Purpose:To evaluate the relationships of right ventricular (RV) and left ventricular (LV) myocardial perfusion reserves with ventricular function and pulmonary hemodynamics in patients with pulmonary arterial hypertension (PAH) by using adenosine stress perfusion cardiac magnetic resonance (MR) imaging. Materials and Methods:This HIPAA-compliant study was institutional review board approved. Twenty-fi ve patients known or suspected to have PAH underwent right heart catheterization and adenosine stress MR imaging on the same day. Sixteen matched healthy control subjects underwent cardiac MR imaging only. RV and LV perfusion values at rest and at adenosine-induced stress were calculated by using the Fermi function model. The MR imaging-derived RV and LV functional data were calculated by using dedicated software. Statistical testing included KruskalWallis tests for continuous data, Spearman rank correlation tests, and multiple linear regression analyses. Results:Seventeen of the 25 patients had PAH: 11 with sclerodermaassociated PAH, and six with idiopathic PAH. The remaining eight patients had scleroderma without PAH. groups. There were signifi cant correlations between biventricular MPRI and both mean pulmonary arterial pressure (mPAP) (RV MPRI: r = 2 0.59, Bonferroni P = .036; LV MPRI: r = 2 0.79, Bonferroni P , .002) and RV stroke work index (RV MPRI: r = 2 0.63, Bonferroni P = .01; LV MPRI: r = 2 0.75, Bonferroni P , .002). In linear regression analysis, mPAP and RV ejection fraction were independent predictors of RV MPRI. mPAP was an independent predictor of LV MPRI. Conclusion:Biventricular vasoreactivity is signifi cantly reduced with PAH and inversely correlated with RV workload and ejection fraction, suggesting that reduced myocardial perfusion reserve may contribute to RV dysfunction in patients with PAH.q RSNA, 2010
OBJECTIVE-The purpose of this study was to assess predictors of MRI-identified septal delayed enhancement mass at the right ventricular (RV) insertion sites in relation to RV remodeling, altered regional mechanics, and pulmonary hemodynamics in patients with suspected pulmonary hypertension (PH).SUBJECTS AND METHODS-Thirty-eight patients with suspected PH were evaluated with right heart catheterization and cardiac MRI. Ten age-and sex-matched healthy volunteers acted as controls for MRI comparison. Septal delayed enhancement mass was quantified at the RV insertions. Systolic septal eccentricity index, global RV function, and remodeling indexes were quantified with cine images. Peak systolic circumferential and longitudinal strain at the sites corresponding to delayed enhancement were measured with conventional tagging and fast strainencoded MRI acquisition, respectively. RESULTS-PH was diagnosed in 32 patients. Delayed enhancement was found in 31 of 32 patients with PH and in one of six patients in whom PH was suspected but proved absent (p = 0.001). No delayed enhancement was found in controls. Delayed enhancement mass correlated with pulmonary hemodynamics, reduced RV function, increased RV remodeling indexes, and reduced eccentricity index. Multiple linear regression analysis showed RV mass index was an independent predictor of total delayed enhancement mass (p = 0.017). Regional analysis showed delayed enhancement mass was associated with reduced longitudinal strain at the basal anterior © American Roentgen Ray Society Address correspondence to J. Vogel-Claussen.. N. F. Osman is a founder and a shareholder in Diagnosoft, Inc. The terms of this arrangement have been approved by Johns Hopkins University in accordance with its conflict of interest policies. NIH Public AccessAuthor Manuscript AJR Am J Roentgenol. Author manuscript; available in PMC 2012 January 1. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript septal insertion (r = 0.6, p < 0.01). Regression analysis showed that basal longitudinal strain remained an independent predictor of delayed enhancement mass at the basal anterior septal insertion (p = 0.02).CONCLUSION-In PH, total delayed enhancement burden at the RV septal insertions is predicted by RV remodeling in response to increased afterload. Local fibrosis mass at the anterior septal insertion is associated with reduced regional longitudinal contractility at the base. Keywordsdelayed enhancement; fast strain-encoded imaging; MRI; pulmonary hypertension; tagging Pulmonary hypertension (PH) is a complex chronic disorder of the pulmonary circulation that has a variety of causes. It is diagnostically and therapeutically challenging and usually has a poor prognosis [1,2]. PH occurs as a result of remodeling of the distal pulmonary arterioles (and venules in the case of pulmonary venous hypertension), which leads to elevated pressure and resistance in the pulmonary vascular bed and to right ventricular (RV) structural and functional remodeling. High mortality is relat...
CE MR-derived PTT, LV FWHM, and LV TTP are noninvasive compound markers of pulmonary hemodynamics and cardiac function in patients with PAH. Their predictive value for patient outcome warrants further investigation.
-Claussen, MD Purpose:To determine whether chronic pulmonary arterial pressure (PAP) elevation affects regional biventricular function and whether regional myocardial function may be reduced in pulmonary arterial hypertension (PAH) patients with preserved global right ventricular (RV) function. Materials and Methods:After informed consent, 35 PAH patients were evaluated with right heart catheterization and cardiac magnetic resonance (MR) imaging and compared with 13 healthy control subjects. Biventricular segmental, section, and mean ventricular peak systolic longitudinal strain (E LL ), as well as left ventricular (LV) circumferential and RV tangential strains were compared between PAH patients and control subjects and correlated with global function and catheterization of the right heart indexes. Spearman r correlation with Bonferroni correction was used. Multiple linear regression analysis was performed to determine predictors for regional myocardial function. Results:In the RV of PAH patients, longitudinal contractility was reduced at the basal, mid, and apical levels, and tangential contractility was reduced at the midventricular level.Mean RV E LL positively correlated with mean PAP (r = 0.62, P , .0014) and pulmonary vascular resistance index (PVRI) (r = 0.77, P , .0014). Mean PAP was a predictor of mean RV E LL (b = .19, P = .005) in a multiple linear regression analysis. In the LV, reduced LV longitudinal and circumferential contractility were noted at the base. LV anteroseptal E LL positively correlated with increased mean PAP (r = 0.5, P = .03) and septal eccentricity index (r = 0.5, P = .01). In a subgroup of PAH patients with normal global RV function, significantly reduced RV longitudinal contractility was noted at basal and mid anterior septal insertions, as well as the mid anterior RV wall (P , .05 for all). Conclusion:In PAH patients, reduced biventricular regional function is associated with increased RV afterload (mean PAP and PVRI). Cardiac MR imaging helps identify regional RV dysfunction in PAH patients with normal global RV function.q RSNA, 2012 Supplemental material: http://radiology.rsna.org/lookup /suppl
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