title: Comparison of the diagnostic utility of cardiac magnetic resonance imaging, computed tomography, and echocardiography in assessment of suspected pulmonary arterial hypertension in patients with connective tissue disease.
abstract: OBJECTIVE
  Pulmonary arterial hypertension (PAH) is a life-threatening complication of connective tissue diseases (CTD). Our aim was to compare the diagnostic utility of noninvasive imaging modalities, i.e., magnetic resonance imaging (MRI), computed tomography (CT), and echocardiography, in evaluation of these patients.
  
  
  METHODS
  In total, 81 consecutive patients with CTD and suspected PH underwent cardiac MRI, CT, and right heart catheterization (RHC) within 48 hours. Functional cardiac MRI variables [ventricle areas and ratios, delayed myocardial enhancement, position of the interventricular septum, right ventricular mass, ventricular mass index (VMI), and pulmonary artery distensibility] were all evaluated. The pulmonary artery size, pulmonary artery/aortic ratio (PA/Ao), left and right ventricular (RV) diameter ratio, RV wall thickness, and grade of tricuspid regurgitation were measured on CT. Tricuspid gradient (TG) and size of the RV were assessed using echocardiography.
  
  
  RESULTS
  In our study of 81 patients with CTD, 55 had PAH, 22 had no PH, and 4 had PH owing to left heart disease. There was good correlation between mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR) measured by RHC and VMI derived from MRI (mPAP, r = 0.69, p < 0.001; PVR, r = 0.78, p < 0.001) and systolic area ratio (mPAP, r = 0.69, p < 0.001; PVR, r = 0.68, p < 0.001) and TG derived from echocardiography (mPAP, r = 0.84, p < 0.001; PVR, r = 0.76, p < 0.001). In contrast, CT measures showed only moderate correlation. MRI and echocardiography each performed better as a diagnostic test for PAH than CT-derived measures: VMI ≥ 0.45 had a sensitivity of 85% and specificity 82%; and TG ≥ 40 mm Hg had a sensitivity of 86% and specificity 82%. Univariate Cox regression analysis showed the MRI measurements were better at predicting mortality. Patients with RV end diastolic volume < 135 ml had a better prognosis than those with a value > 135 ml, with a 1-year survival of 95% versus 66%, respectively.
  
  
  CONCLUSIONS
  In patients with CTD and suspected PAH, cardiac MRI and echocardiography have greater diagnostic utility than CT in the assessment of patients with suspected PAH, and MRI has prognostic value.
authors.affiliation: Unit of Academic Radiology, University of Sheffield, Sheffield, UK. s.rajaram@sheffield.ac.uk
authors.forename: Smitha
authors.initials: S
authors.lastname: Rajaram
authors.forename: Andrew James
authors.initials: AJ
authors.lastname: Swift
authors.forename: David
authors.initials: D
authors.lastname: Capener
authors.forename: Charles A
authors.initials: CA
authors.lastname: Elliot
authors.forename: Robin
authors.initials: R
authors.lastname: Condliffe
authors.forename: Christine
authors.initials: C
authors.lastname: Davies
authors.forename: Catherine
authors.initials: C
authors.lastname: Hill
authors.forename: Judith
authors.initials: J
authors.lastname: Hurdman
authors.forename: Rachael
authors.initials: R
authors.lastname: Kidling
authors.forename: Mohammed
authors.initials: M
authors.lastname: Akil
authors.forename: Jim M
authors.initials: JM
authors.lastname: Wild
authors.forename: David G
authors.initials: DG
authors.lastname: Kiely
mesh_terms: D006328:Cardiac Catheterization; D003240:Connective Tissue Diseases / Q000150:complications / Q000175:diagnosis* / Q000401:mortality; D004452:Echocardiography / Q000379:methods*; D065627:Familial Primary Pulmonary Hypertension; D005260:Female; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000209:etiology / Q000401:mortality; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D011237:Predictive Value of Tests; D011379:Prognosis; D011651:Pulmonary Artery / Q000473:pathology*; D012189:Retrospective Studies; D015996:Survival Rate; D014057:Tomography, X-Ray Computed / Q000379:methods*; D006113:United Kingdom / Q000453:epidemiology