| Objective: To evaluate the clinical implication of the integrated backscatter (IBS) in assessing diabetic cardiomyopathy.Methods: The subjects included 60 type-II diabetes mellitus (DM) patients and 30 age- and gender- matched normal volunteers (control group, male 21 and female 9 with a mean age of 44.6+8.85 years). The diabetic patients were divided into 2 groups according to the present of complications such as diabetic retinopathy or diabetic nephropathy. DM-I group was composed of 30 patients without complications (male 22 and female 8 with a mean age 43.37+8.45 years), and DM-II group consisted of 30 patients with complications (male 20 and female 10 with a mean age 45.6+10.24 years). A color Doppler ultrasonic system (HP Sonos-5500) with acoustic densitometry (AD) analysis software was used. The parasternal short axis view of left ventricle at papillary muscle level was acquired, and 5 continuous beats were recorded and saved to CD. Then the machine was shifted to AD-IBS condition. Under a fixedsetting, 62 continuous frames were recorded and saved to CD for off-line analysis. Region of interest (ROI) was placed at anterior wall (AW), lateral wall (LW), posterior wall (PW), inter-ventricular septum (IVS) and the center of left ventricle (LV). The average of integrated backscatter (All) and cyclic variation of integrated backscatter (CVIB) of every ROI were measured. All and CVIB were corrected as follows: IBS% = All of myocardium/All of blood in LV, and CVIB% - CVIB / AIL Ejection fraction (EF) and fractional shorting (FS) of LV were calculated with Teichholtz method and the thickening rates of IVS, PW, AW and LW were defined as the following formula: A T% = (wall thickness at end systole - wall thickness at end diastole)/ wall thickness at end diastole X 100%. LV diastolic function parameters was derived from the inflow spectrum of mitral valve, including the ratios of peak velocities (E/A) and velocity time intergral (TVI-E/TVI-A) of E wave and A wave, and deceleration time of E wave (DT). Biochemical parameters included fasting plasma glucose (FPG), 2-h post plasma glucose (PPG) and HbAlc. The duration of disease was also analyzed.Results: (1) IBS change periodically in normal subjects. The value was maximal at end diastole and was minimal at end systole. IBS also change periodically in DM, but the form of the curve were abnormal. (2) IBS% was significantly higher in DM-I and DM-n than in control group, and CVIBS% showed a significantly lower value in DM-IIthan in control group in IVS and PW. (3) No significant difference was found in LV systolic parameters whereas diastolic parameters (E/A, TVI-E/TVI-A, DT) were found different between DM-II and control group. (4) The duration of DM-II was significantly longer than DM-I, and there was no significant difference in biochemical parameters between DM-I and DM-II. (5) There was no significant correlation between IBS% and EF, FS and diastolic parameters; CVIBS% in IVS and PW showed a significant correlation with A T% of the same region. (6) IBS% showed a significant correlation with blood glucose of 2 hours after dinner and no significant correlation with other biochemical parameters and the duration of disease.Conclusions: Myocardial tissue characterization of diabetic patients is significantly different from normal control subjects. IBS may be a clinically practical modality in assessing quantitatively the early diabetic cardiomyopathy.
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