Non-invasive flap-assessment
techniques
Acoustic Doppler sonography (HHD) andColour-coded duplex
sonography (DS)
Colour-coded duplex sonography (DS), a vital modality in medical
diagnostics, combines the strengths of anatomic visualization and flow
assessment through ultrasonography. This technique relies on two primary
displays: color-flow Doppler and gray-scale B-mode imaging. Color-flow
Doppler provides valuable insight into flow velocity distribution within
tissues, highlighting areas of abnormal flow patterns such as turbulence
or stenosis. This dynamic representation aids in the identification of
vascular pathologies such as arterial occlusions or venous
insufficiencies. In contrast, grey-scale B-mode imaging offers detailed
anatomical images, allowing for precise localization of structures and
abnormalities. This static view complements the dynamic information
provided by colour-flow Doppler, enabling a comprehensive assessment of
vascular and tissue health. By integrating these two displays, duplex
sonography facilitates a thorough evaluation of vascular structures and
flow dynamics, enhancing diagnostic accuracy and informing treatment
decisions. [29]
HHD is considered the most common and cost-effective technique for
finding perforators in breast surgery, for example. (see Figure 2)
Although it can determine the relative position of a perforator, it
carries the risk of false positive findings (for example other
subcutaneous arteries and not perforators) due to its high sensitivity.
Furthermore, this modality does not provide information on the exact
anatomical course. However, it remains a useful tool for intraoperative
evaluation of vessel courses and assessment of perforators. In
comparison, DS provides more detailed information on vessel anatomy (see
Figure 3), however, it requires in-depth knowledge of the anatomy and is
more time-consuming and technically demanding. In comparison with the
CTA and MTA mentioned below, the DS is unable to provide
three-dimensional information about vascular anatomy. [30]