UTC the modality

Computerized “Ultrasound Tissue Characterization” (UTC) consists of both hard- and soft- ware. A pivotal role in the configuration plays the UTC-Trackera precision instrument that moves the ultrasound probe automatically across the region of interest, e.g. along a tendon’s long axis, collecting transverse images at even distances of 0.2 mm over a length of 12 cm. These images are stored real-time in a high-capacity laptop computer and by compounding contiguous transverse images, a 3-D ultrasound data-block is created that can be used for (A) tomographic visualization and (B) tissue characterization and quantification of architecture and integrity of the collagenous matrix.

Tomographic visualization

The 3-D ultrasound data-block can be scrolled-through and regions of interest can be visualized instantaneously in 3 planes of view plus a 3-D rendered view over a length of 12 cm. For instance, tendons and ligaments are visualized in:

4-view-grey

  1. transverse plane 
  2. sagittal plane
  3. coronal plane
  4. 3-D rendered coronal view

 

 

In this way, scrolling through the ultrasound data facilitates a real-time “surgeon’s view” in which skin, paratenon and tendon’s interior can be discriminated. This inward view allows a reliable evaluation of integrity or extent of disintegration. As such, this tomographic visualization can be used for targeted and minimally invasive interventions.

Tissue characterization

Fundamental research revealed that the dynamism of echo-patterns is strongly related to the architecture and integrity of collagenous matrices. Dedicated UTC-Algorithms can quantify the dynamism of echo-patterns in contiguous images and these features can be related to architecture and integrity of the collagenous matrix with histo-morphology of tissue specimen as reference test. For instance, in tendon tissue 4 different echo-types can be discriminated and related to stages of integrity, namely:

  • echo-type I, generated by reflections at intact and aligned tendon bundles (coloured green in processed images)
  • echo-type II, generated by reflections at discontinuousecho-types or waving tendon bundles (coloured blue in processed images)
  • echo-type III, generated by interfering echoes from mainly fibrillar components (coloured red in processed images)
  • echo-type IV, generated by mainly cellular components and fluid in amorphous tissue (coloured black in processed images)

This ultra-structural information is A. visualized tomographically in 3 planes of view and B. quantified by means of the calculation of respective percentages of echo-types. The ratios of these 4 echo-types appeared to be highly correlated with histo-morphological characteristics of tendon tissue, showing the discriminative power of UTC for tissue characterization.