Automated detection of left ventricular dyskinesis by gated blood pool SPECT.
OBJECTIVE
The ability to detect left ventricular (LV) apical dyskinesis, the hallmark of an aneurysm, is an important requirement of diagnostic cardiac imaging modalities that perform wall motion analysis. Our investigation assessed the ability of gated blood pool single-photon emission-computed tomography (GBPS) to automatically detect LV dyskinesis, using cardiac magnetic resonance (CMR) as the reference standard.


METHODS
GBPS data were analyzed for 41 patients with congestive heart failure or cardiomyopathy and compared with ECG-gated TrueFISP CMR evaluations. An experienced nuclear cardiologist without the knowledge of quantitative GBPS or CMR results graded visual impressions of regional wall motion while examining cinematic playbacks of GBPS images. GBPS algorithms automatically isolated LV counts and computed regional phase (phi) values in each of 17 conventional American Heart Association LV segments. LV asynchrony was quantified by the two local measures: maximum apical phi difference (Deltaalpha), and standard deviation among apical phases (sigmaalpha), and by the five global measures: varphi histogram bandwidth (BWHistogram), phi histogram standard deviation (sigmaHistogram), Z-scores, Entropy, and Synchrony. For CMR data, an expert manually drew endocardial LV outlines to measure regional wall motion in 17 LV segments.


RESULTS
Apical dyskinesis was present in nine patients. Among GBPS measurements, the method with the greatest accuracy for detecting dyskinesis was Deltaalpha (receiver operating characteristic area=95%). The only method with a sufficiently high kappa statistic to represent 'very good agreement' with CMR was Deltaalpha, with kappa=0.81. Deltaalpha was more sensitive in detecting dyskinesis than visual analysis (100 vs. 33%, P=0.01).


CONCLUSIONS
Automatic GBPS computations accurately identified patients with LV dyskinesis, and detected dyskinesis more successfully than did visual analysis.
Nichols
Kenneth J
KJ
Division of Nuclear Medicine and Molecular Imaging, North Shore-Long Island Jewish Health System, Manhasset and New Hyde Park, NY 11040, USA. knichols@lij.edu
Van Tosh
Andrew
A
Wang
Yi
Y
De Bondt
Pieter
P
Palestro
Christopher J
CJ
Reichek
Nathaniel
N
D001331:Automation; D055426:Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography / Q000379:methods* / Q000592:standards; D005260:Female; D015637:Gated Blood-Pool Imaging / Q000379:methods* / Q000592:standards; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012015:Reference Standards; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*