Cardiac MRI in the Assessment of Pulmonary Hypertension

Cardiac Magnetic Resonance Imaging (CMR) is an effective tool for evaluating patients with pulmonary arterial hypertension (PAH), according to a new meta-analysis published in JACC: Cardiovascular Imaging.

The study's authors analyzed data from 22 different studies, covering nearly 2,000 patients with pulmonary hypertension.  There were 18 clinical worsening events and 8 deaths per 100 patient-years.

The researchers determined CMR to be a powerful tool for predicting clinical worsening in PHA patients, with every 1% decrease in right ventricular ejection fraction associated with a 4.9% increase in the risk of clinical worsening over the next 22 months and a 2.1% increase in the risk of mortality over the next 54 months.

The authors concluded that CMR can effectively predict clinical worsening in PHA patients.   

AI can diagnose Myocardial Infarction on non-enhanced MRI

A retrospective study of 212 patients published in Radiology used deep learning (AI) to identify and delineate chronic myocardial infarction without late gadolinium enhancement.

The model extracted motion features from the left ventricle on non-enhanced cardiac cine MRI and its per-segment sensitivity and specificity was 90% and 99 percent, therefore deep learning on non-enhanced cine cardiac MRI data can detect the presence and extent of chronic myocardial infarction. 

This approach has the potential to reduce the use of gadolinium contrast administration in patients with renal impairment, which is common in patients with coronary artery disease.

Thrombi in left atrium can be detected with cardiac MRI

Kitkungvan et al report in the J Am CollCardiovascular Imaging that left atrial (LA) and left atrial appendage (LAA) thrombi can be detected with cardiac MRI (CMR) – without the need of a trans-esophageal echocardiogram (TEE) – before pulmonary vein isolation (PVI) is performed.

They studied 261 patients with congestive heart failure, hypertension, diabetes mellitus, stroke/transient ischemic attack, vascular disease, with CMR and TEE for evaluation of pulmonary venous anatomy before PVI. LA and LAA thrombi were evaluated by using CMR as follows: 1) cine-CMR; 2) contrast-enhanced magnetic resonance angiography; and 3) equilibrium phase delayed enhancement (DE) CMR with a long inversion time (TI) of 600 ms (long TI DE-CMR).

CMR and TEE were performed within 1.3 ± 2.3 days. LA/LAA thrombi were discovered in 9 patients (3.5%) by using TEE. Among the CMR techniques performed, long TI DE-CMR had the highest diagnostic accuracy (99.2%), sensitivity (100%), and specificity (99.2%), followed by contrast-enhanced magnetic resonance angiography accuracy (94.3%); sensitivity (66.7%); and specificity (95.2%) and cine-CMR accuracy (91.6%); sensitivity (66.7%); and specificity (92.5%).

The authors concluded that patients who were candidates for pulmonary vein isolation surgery, cardiac MRI with long inversion time delayed enhancement independently picked up LA and LAA clots in the same 3.5% of patients as did gold-standard TEE, thus CMR could be the single diagnostic study for assessment of pulmonary venous anatomy as well as presence of atrial thrombi thus reducing the number of pre-operative tests before PVI.