title: Impact of second harmonic imaging on the determination of the global and regional left ventricular function by 2D echocardiography: a comparison with MIBI gated SPECT.
abstract: OBJECTIVE
  To evaluate the impact of second harmonic (SH) compared to fundamental mode (FM) imaging on the echocardiographic determination of ejection fraction (EF) and wall motion score index (WMSI), using MIBI gated SPECT as an independent reference.
  
  
  METHODS
  Sixty-two consecutive patients underwent an echocardiography study and a MIBI gated SPECT over 24 hours. EF was estimated visually (estimated-E) and was calculated with the Simpson biplane method (Tracing-T), for both FM and SH. WMSI was determined by two independent echo-readers blinded to the nuclear imaging results. The same segmentation and scoring system was used for WMSI determined by MIBI gated SPECT.
  
  
  RESULTS
  The percentages of unscored segments because of suboptimal endocardial border detection were 19.5% (FM) and 9.0% (SH). The correlation coefficients (r) between SPECT-EF and echo-EF were: FM (E)=0.705, FM (T)=0.546, SH (E)=0.771, SH (T)=0.743. Agreement between SPECT-EF and echo-EF was acceptable for both imaging modalities (mean of the difference +/- 2 S.D.): -2.8 +/- 18.5 (FM) and -3.5 +/- 16.4 (SH). Correlation coefficients (r) between WMSI calculated by SPECT and by echo were 0.715 (FM) and 0.789 (SH). Agreement between SPECT-WMSI and echo-WMSI was good for all imaging modes but better with SH compared to FM: 0.12 +/- 0.91 (FM), 0.10 +/- 0.77 (SH). The interobserver correlation coefficients (r) for the WMSI were 0.939 (FM) and 0.996 (SH). The agreement between the two observers was better for SH compared to FM. The systematic differences (mean differences) were 0.21 (FM) and -0.01 (SH), and the random differences between both observers (2 S.D.) decreased from 1.55 (FM) to 0.29 (SH).
  
  
  CONCLUSIONS
  The use of SH echocardiography decreases the number of unscored segments. This results in an important gain in correlation and agreement for EF determination between echo and SPECT, and in a considerable decline of the interobserver variability for the echo-determined WMSI. WMSI determined by MIBI gated SPECT correlated closely with the SH WMSI, and agreement between both methods was excellent.
authors.affiliation: Department of Cardiology, Academic Hospital of the Free University of Brussels, Belgium.
authors.forename: G
authors.initials: G
authors.lastname: Van Camp
authors.forename: R R
authors.initials: RR
authors.lastname: Franken
authors.forename: D
authors.initials: D
authors.lastname: Schoors
authors.forename: Y
authors.initials: Y
authors.lastname: Hagers
authors.forename: M
authors.initials: M
authors.lastname: Koole
authors.forename: D
authors.initials: D
authors.lastname: Demoor
authors.forename: P
authors.initials: P
authors.lastname: Melis
authors.forename: P
authors.initials: P
authors.lastname: Block
mesh_terms: D000368:Aged; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D015588:Observer Variation; D012044:Regression Analysis; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D017256:Technetium Tc 99m Sestamibi