The Use of A Wide Dynamic Range Algorithm to Improve Diagnostic Abilities in Echocardiographic Images

Hedva Spitzer , Biomedical Engineering, Tel Aviv University,
Micha Feinberg , Heart Institute, Sheba Medical Center,
Faculty of Medicine -Tel Aviv University

The aim of the research was to develop the use of a wide dynamic range algorithm recently developed in the laboratory of wide dynamic range imaging (Hedva Spitzer) to improve the diagnostic capability of ultrasound images in cardiology.

A. The adaptation of the algorithm to echocardiographic images.

Methods:
In the first stage we adapted the wide dynamic range algorithm by changing some of its functional parameters to specifically improve echocardiographic images.
Results: Echocardiographic image before and after the use of the algorithm.



It is noticeable that the use of the algorithm significantly improved the ability to discriminate left ventricular endocardial cavity borders.

B. The use of the wide dynamic range algorithm to measure left ventricular volume and systolic functional parameters.

Methods:
We assessed the accuracy of left ventricular volume measurement before and after applying the specifically adapted wide dynamic range algorithm by calculating the difference of the standard deviation between 12 professional observers (technicians and physicians). The Left ventricular volume (Biplane Simpsonís method) was measured at end systole and end diastole from the apical 4 chamber and apical 2 chamber views in 100 images of different qualities from 25 patients. The parameters actually measured were LV area and long axis length. Two statistical parameters were used ; t-test (parametric), Wilcox test (aparametric) and a normal Gausian distribution of the two samples was assumed.

Results:
The table presents the probability to accept the assumption that there is no change in the standard deviation before and after using the algorithm.

Parameter Parametric test Aparametric test
T testNormality of
samples
F test
(homogeneity of
variance)
Wilcox
Area0.000521570.8150.000565
Length 0.0040037570.2230.003698
Volume0.0018701440.6640.000687
Stroke volume0.0223923570.3520.001861
Ejection fraction0.000521570.759 0.002431

Conclusions:
The results presented show that the variance between different observers becomes significantly smaller after the use of the wide dynamic range algorithm and demonstrate the ability of the algorithm to improve the accuracy of extracting basic systolic left ventricular functional characteristics from echocardiographic images.