Overview of left ventricular outpouchings on cardiac magnetic resonance imaging

Abstract

Left ventricular outpouchings commonly include aneurysm, pseudoaneurysm, and diverticulum and are now being increasingly detected on imaging. Distinction between these entities is of prime importance to guide proper management as outcomes for these entities differ substantially. Chest radiograph is usually nonspecific in their diagnosis. Echocardiography, multi-detector computed tomography evaluation and angiography are helpful in the diagnosis with their inherit limitations. Cardiac magnetic resonance imaging (MRI) is emerging as a very useful tool that allows simultaneous anatomical and functional evaluation along with tissue characterization, which has diagnostic, theraputic and prognostic implications. This article gives an overview of left ventricular outpouchings with special emphasis on their differentiation using cardiac MRI.

Keywords: Diverticulum; aneurysm; magnetic resonance imaging (MRI); pseudoaneurysm.

Figure 1

Left ventricular aneurysm: serial magnetic resonance images show wide-necked outpouching from inferobasal left ventricular wall (arrow in A) which appears relatively larger in systole (B) than diastole (C) with regional transmural perfusion deficit (arrowhead in D). Late gadolinium enhanced images depict continuous transmural enhancement (arrowheads in E, F) without pericardial enhancement (arrow in E depicting pericardium as distinct dark line).

Figure 2

Left ventricular pseudoaneurysm: serial magnetic resonance images show left ventricular inferior wall outpouching (arrow in A) with relatively narrow neck which appears relatively larger in systole (B) than diastole (C). On perfusion images, inferior and inferoseptal wall shows subendocardial perfusion deficit (arrowhead in D) with transmural deficit in the wall of outpouching (arrowhead in E). Late gadolinium enhanced image depicts subendocardial enhancement (arrowhead in F) in inferoseptal and inferior wall. Delayed enhancement is also seen in the wall of outpouching with obliteration of myocardial-pericardial interface (arrow in G) and pericardial enhancement (arrowhead in H).

Figure 3

Septal diverticulum: serial magnetic resonance images show wide-necked outpouching (arrow in A) from mid muscular septum. No altered myocardial signal intensity seen on T2 weighted image (arrowhead in B). It shows synchronous contraction and appears relatively larger in diastole (C) than systole (D). Perfusion image shows no perfusion deficit (arrowhead in E). Delayed gadolinium enhanced images reveal no abnormal enhancement (arrow in F, G).