Assessment of segmental wall motion is one of the most challenging tasks in echocardiography. The diagnosis of ischemic heart disease by echocardiography depends on the accurate detection of segmental wall motion abnormalities. However, echocardiographic regional wall motion analysis is impaired by incomplete endocardial definition due to obesity, chronic obstructive lung disease, etc. The purpose of this study was to examine the value of tissue harmonic imaging for endocardial border definition.

We recorded echocardiograms in 30 consecutive patients, in which more than one segment of left ventricule were poorly visualized, by ATL HDI 3000 and analyzed left ventricular segmental wall motion and then recorded echocardiograms again by tissue harmonic imaging (THI) technique. Endocardial border definition for each segment was graded from grade A to C (grade A in which endocardium is clearly visualized, grade B in which endocardium is poorly visualized and grade C in which endocardium is not seen). Densitometric analysis was perfromed in 10 randomly selected patients. Mean density and dynamic range in histogram were obtained at septum, posterior wall and left ventricle cavity on parasternal long axis view with both techniques.

Among total 480 segments, 237 segments (49.4%) were categorized as grade A, 152 segments (31.7%) were categorized as grade B and 91 segments (18.9%) were categorized as grade C in fundamental modes. However, 380 segments (79.2%) were categorized as grade A, 75 segments (15.6%) were categorized as grade B and 25 segments (5.2%) were categorized as grade C in tissue harmonic modes. Visualization of 37.7% (181 segments/480 segments) of all segments was improved in tissue harmonic imaging, with 5.2% (25 segments/480 segments) improved from "not seen" to "clearly visualized". Of these improved 181 segments in THI, 105 segments (58%) were the lateral and anterior walls on apical views. In densitometric analysis of septum, wall density and delta density (wall densityLV cavity density) were significantly higher in THI than fundamental modes (p<0.05). But, W/C ratio (wall density/LV cavity density) was not different between two imaging modalities. In densitometric analysis of posterior wall, all parameters were not significantly different between two imaging modalities. Also, W/C ratio of dynamic range (posterior wall dynamic range/LV cavity dynamic range) was not significantly different between two imaging modalities.

Tissue harmonic imaging has significant value in endocardial border definition in the patients with poor echocardiographic windows and appears promising with the added advantage of no requirement for intravenous access.