Smitha Rajaram

Background/Objectives: Pulmonary artery (PA) dilatation and slow-flow are imaging features of pulmonary hypertension (PH), but their quantitative assessment on routine cardiovascular magnetic resonance (CMR) remains limited. This study aimed to develop and evaluate an automated CMR pipeline for quantifying PA size-based and slow-flow metrics from routine white-blood (WB) and black-blood (BB) acquisitions. Methods: A total of 205 CMR acquisitions (106 WB and 99 BB) were used for model development and independent testing. Separate deep learning nnU-Net-based segmentation models were developed for WB and BB acquisitions using a two-stage cascaded framework. Automated measurements included PA volume and PA slow-flow. The trained models were subsequently applied to a larger cohort of 1471 patients using available WB and BB acquisitions to assess automated measurement extraction and agreement with clinical reports. Results: Automated PA volumetric measurements demonstrated excellent agreement with manual reference measurements for both the WB and BB models (ICC 0.94 and 0.93, respectively), with high segmentation accuracy (Dice 0.86 and 0.80, respectively). Automated slow-flow measurements also demonstrated excellent volumetric agreement (ICC 0.94), despite lower spatial overlap (Dice 0.61). Automated slow-flow classification demonstrated 83% agreement with qualitative clinical reporting (κ = 0.58). Conclusions: Automated PA volumetric quantification from routine CMR is feasible. Automated slow-flow quantification showed promising performance but requires validation across scanner vendors and BB acquisition protocols before broader clinical application.

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.Conclusion.: 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.

The study demonstrates that there is a potential role for the balanced steadystate free precession sequence as an alternative radiation-free noncontrast imaging modality. PurposeTo evaluate the utility of 1.5-T noncontrast magnetic resonance (MR) imaging of the lung parenchyma and to compare it with computed tomography (CT) in the assessment of interstitial lung disease and other morphologic lung abnormalities.Materials and MethodsInstitutional review board approval was obtained for retrospective image analysis. A total of 236 patients who underwent MR imaging and CT as part of their assessment for suspected pulmonary hypertension were included in this study. Lung MR imaging was performed with a 1.5-T system as a stack of axial two-dimensional balanced steady-state free precession (bSSFP) acquisitions. Two radiologists independently evaluated CT and MR images for various morphologic abnormalities, such as pulmonary fibrosis, pleural and mediastinal disease, solid lesions, bronchial disease, and emphysema. Κ statistics were used to measure interobserver agreement.ResultsSensitivity and specificity of MR imaging in the identification of pulmonary fibrosis (n = 46) were 89% (...

To evaluate the diagnostic accuracy of contrast-enhanced MR angiography (CE-MRA) and the added benefit of unenhanced proton MR angiography compared with CT pulmonary angiography (CTPA) in patients with chronic thromboembolic disease (CTE).