title: Harmonic imaging improves estimation of left ventricular mass.
abstract: OBJECTIVE
  To assess the effect of tissue harmonic imaging (THI) on assessment of left ventricular mass index (LVMI) measurements by M-mode trans-thoracic echocardiography, when compared with magnetic resonance imaging (MRI).
  
  
  METHODS
  20 hypertensive male subjects were studied. LVMI was measured in all subjects by both gradient-echo MRI (Lscelsint Prestige 1.9 T) and by transthoracic echocardiography (ATL HDI 5000). M-mode echocardiography recordings were taken for each patient, two with fundamental imaging (FI) and two using THI in a randomised order and the images unlabelled. Recordings were analysed off-line, by a blinded observer. LVMI by MRI was calculated using Simpson's rule on serial short axis slices of 8 mm thickness. Data are expressed as mean +/- SD.
  
  
  RESULTS
  There was a difference in LVMI measurements between FI and THI (LVMI) (79 +/- 20 vs. 93 +/- 25 g2; p < 0.001). A lower mean difference was obtained by THI, compared to FI, when compared with MRI (2 +/- 15 vs. -32 +/- 22 g2; p < 0.001) suggesting that FI underestimates LVMI. Inter-observer variability was similar between THI and FI (4.5 +/- 15 vs. 6.4 +/- 15 g2; p = 0.46).
  
  
  CONCLUSIONS
  In hypertensive males, M-mode echo derived from FI underestimated LVMI. These results imply that widely accepted reference ranges for LVMI using FI are not applicable when THI is used.
authors.affiliation: Department of Cardiology, Western General Hospital, The University of Edinburgh, Edinburgh EH4 2XU, UK.
authors.forename: James C S
authors.initials: JC
authors.lastname: Spratt
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Leslie
authors.forename: Audrey
authors.initials: A
authors.lastname: White
authors.forename: Lynn
authors.initials: L
authors.lastname: Fenn
authors.forename: Colin
authors.initials: C
authors.lastname: Turnbull
authors.forename: David B
authors.initials: DB
authors.lastname: Northridge
mesh_terms: D000328:Adult; D004452:Echocardiography; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000453:epidemiology; D017379:Hypertrophy, Left Ventricular / Q000175:diagnosis* / Q000453:epidemiology; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008297:Male; D015588:Observer Variation; D011859:Radiography