Quantitative assessment of regional left ventricular function with cardiac MRI: three-dimensional centersurface method.
OBJECTIVE
The purpose of this study was to provide the first in vivo validation of a three-dimensional (3D) method to quantify regional left ventricular (LV) function with cardiac magnetic resonance (CMR) imaging after myocardial infarction (MI).


BACKGROUND
Current cardiac methods to analyze LV function are limited by geometric assumptions and observer biases.


METHODS
MI was induced percutaneously by 90-min proximal left circumflex artery balloon occlusion in 25 Yucatan minipigs. Cine and contrast-enhanced (CE) CMR imaging was performed at 5 days (n = 21) and 8 weeks (n = 22) post-MI. Twelve control animals without MI were also imaged. Regional wall thickening was measured orthogonal to the myocardial wall using the centersurface method. The left ventricle was divided into 16 segments (six basal 60 degrees , six middle 60 degrees , four apical 90 degrees ). Normal ranges for segmental wall thickness and wall thickening were defined as mean +/- 2D in control hearts. Hypokinesis was defined as a segmental thickening value below the normal range.


RESULTS
Hypokinesis following MI was identified in the inferior, inferolateral and anterolateral segments when compared with controls and corresponded to areas of infarction by CE CMR. The aggregate wall thickening was also expressed as a percentage at 5 days (Infarct zone: 15% +/- 16% vs. NonInfarct zone 33% +/- 20%, P < 0.001) and 8 weeks (Infarct zone 20% +/- 20% vs. NonInfarct zone 32% +/- 22%, P < 0.001).


CONCLUSIONS
The centersurface method can quantify regional wall thickening and spatially identify regions of abnormal function in 3D after MI without relying on geometric assumptions. This method may be a valuable tool to quantify regional LV function in the assessment of myocardial viability, ischemia, infarction, and the response to therapeutic interventions.
Beohar
Nirat
N
Bluhm Cardiovascular Institute, Northwestern Memorial Hospital, Northwestern University, Chicago, Illinois 60611, USA. n-beohar@northwestern.edu
Flaherty
James D
JD
Davidson
Charles J
CJ
Vidovich
Mladen I
MI
Brodsky
Adam
A
Lee
Daniel C
DC
Wu
Edwin
E
Bolson
Edward L
EL
Bonow
Robert O
RO
Sheehan
Florence H
FH
D000818:Animals; D021721:Balloon Occlusion; D003287:Contrast Media; D004195:Disease Models, Animal; D005682:Gadolinium; D006571:Heterocyclic Compounds; D017379:Hypertrophy, Left Ventricular / Q000473:pathology / Q000503:physiopathology; D007091:Image Processing, Computer-Assisted; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods; D008955:Models, Cardiovascular; D009203:Myocardial Infarction / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D009942:Organometallic Compounds; D012107:Research Design; D013318:Stroke Volume; D013552:Swine; D013556:Swine, Miniature; D016277:Ventricular Function, Left
D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C062402:gadoteridol; D005682:Gadolinium