Objective selection of short-axis slices for automated quantification of left ventricular size and function by cardiovascular magnetic resonance.
BACKGROUND
Quantification of left ventricular (LV) volume from cardiovascular magnetic resonance images relies on subjective and often challenging selection of short-axis (SAX) slices. We hypothesized that this could be solved by defining mitral annular (MA) plane and apex in long-axis (LAX) views, which could be combined with automated LV volume analysis that does not rely on manual tracing of the endocardial border.


METHODS
SAX images from 50 subjects were analyzed using custom software. LV apex and insertion points of the mitral leaflets were marked on LAX views and used to approximate MA plane. End-systolic and end-diastolic LV volumes (ESV, EDV) were measured while including only slices or their parts located between MA plane and LV apex. Endocardial borders were automatically detected using our previously validated algorithm and also manually traced to obtain reference values.


RESULTS
Selection of anatomic landmarks in LAX views allowed automated measurement of LV volumes without the need for subjective slice selection. Intertechnique comparisons resulted in high correlations (EDV: r=0.95; ESV: r=0.96) and small biases (1 and 9ml). Combined three-dimensional displays of LAX and SAX views with the MA plane showed that in 7/10 worst cases, intertechnique discordance was due to incorrect manual tracing at LV base that erroneously included part of atrial cavity in LV volume or excluded part of LV cavity, i.e., incorrect reference values.


CONCLUSIONS
Defining the MA plane and apex in the LAX views obviates the need for subjective slice selection and eliminates errors in LV volume measurements.
Department of Electrical, Electronics and Information Engineering, University of Bologna, Bologna, Italy.
Marco
M
Marino
Department of Electrical, Electronics and Information Engineering, University of Bologna, Bologna, Italy.
Cristiana
C
Corsi
University of Chicago Medical Center, Chicago, IL, USA.
Francesco
F
Maffessanti
University of Chicago Medical Center, Chicago, IL, USA.
Amit R
AR
Patel
University of Chicago Medical Center, Chicago, IL, USA. Electronic address: vmoravi@bsd.uchicago.edu.
Victor
V
Mor-Avi
D000328:Adult; D000368:Aged; D000465:Algorithms; D059925:Anatomic Landmarks; D016022:Case-Control Studies; D005260:Female; D006331:Heart Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology; D012189:Retrospective Studies; D016277:Ventricular Function, Left / Q000502:physiology*
Endocardial border detection; Magnetic resonance imaging; Mitral annular plane; Ventricular function