SCMR 22nd Annual Scientific Sessions
Description of Clinical Presentation:
A 42 year old lady with hypertension and hypercholesterolaemia was admitted to hospital with left sided chest pain radiating to the left shoulder associated with breathlessness, sweating and nausea. A 12 lead electrocardiogram did not show ischemic changes. The serum troponin did rise and fall from 28, 140 to 67 (normal <13ng/L). Dual antiplatelet therapy was commenced for presumed acute myocardial infarction (MI) and coronary angiography demonstrated unobstructed coronary arteries. CMR scan was requested to determine aetiology of the presentation. She was known to have a diagnosis of pulmonary arterio-venous malformations (AVM) from another hospital.
Diagnostic Techniques and Their Most Important Findings:
CMR imaging was acquired with 1.5T Ingenia MRI scanner, Phillips (Best, Netherlands) for cine, T2-weighted, late gadolinium enhancement (LGE) and flow imaging. Additionally, 4D angiography was acquired to assess the great vessels and pulmonary tree (parameters: TR 3.67ms, TE 1.02ms, ﬂip angle 30°, isotropic voxel size 1.8mm3, SENSE undersampling 1.8 (L>R) and 1.5 (F>H).
CMR demonstrated normal biventricular volumes and function, with no myocardial hyperenhancement on T2-weighted images. However, LGE images showed subendocardial enhancement (25-50% transmurality) in the basal inferolateral wall and focal transmural enhancement in the mid septum (Figure 1). Pulmonary phases of 4D angiography demonstrated two nodules (the largest 2 cm) and multiple serpiginous masses in the right lung, all connected to feeding pulmonary artery branches and vein tributaries (Figure 2). Phase contrast velocity mapping of the ascending aorta and pulmonary artery demonstrated Qp:Qs of 0.71, indicating right to left shunt (Figure 3).
Learning Points from this Case:
Pulmonary AVM are rare abnormal vascular communications between pulmonary arteries and veins . Embolic MI occurs in patients with pulmonary AVM due to bypass of the physiological filtering role of the pulmonary capillary bed, which may result in right-to-left shunt of air, thrombi or bacteria . In the context of the normal coronary angiogram, the aetiology of the clinical presentation was most likely due to a paradoxical embolic MI.
Dynamic 4D angiography  allowed accurate identification and tracking of arterial feeding vessels, AVM and venous drainage in 3D format. One previous study demonstrated the feasibility 4D angiography to investigate pulmonary AVM , although did not use isotropic resolution as in this case study.