Purpose: Contrast harmonic ultrasound (CHI) with a linear transducer is a new diagnostic approach
that allows dynamic and quantitative flow detection of tissue perfusion in microsurgery.
The aim of the study was the evaluation of perfusion of the dermal and subdermal layers
of microvascular tissue transplants with CHI in comparison to ICG-fluorescence angiography.
Materials and methods: In a prospective clinical study Indocyanine-Green Fluorescence Video Angiography
and Contrast Enhanced High Resolution Ultrasound (5–10MHz; linear transducer; Logiq
9; GE) were used for evaluation of the microcirculation in 10 transplanted free parascapular
flaps. Two regions were analysed, the centre of the flap and the region of the anastomosis.
The perfusion patterns of both methods were compared.
Results: The perfusion indexes measured by ICG-fluorescence angiography correlated very precisely
in all patients with the quantitative perfusion curves of contrast-enhanced US with
CHI.Two flaps with slow filling and low dye intensity showed low contrast enhancement
in CHI with modified perfusion curves with slow increase. In two cases a reduced perfusion
and filling were found. There were no statistical differences between the two diagnostic
methods (p>0.01).
Conclusion: CHI improves US detections of dermal and subdermal microcirculation in comparison
to ICG fluorescence angiography. CHI is a new diagnostic method for postoperative
monitoring of free flaps.
