Toward noninvasive assessment of flap viability with time-resolved diffuse optical tomography: a preclinical test on rats.

Laura Di Sieno,Davide Contini,Lionel Hervé,Jean-Marc Dinten,Jean-Luc Coll,Michel Berger,Cynthia Hamou,Georges Bettega,Anne Planat-Chrétien,Agathe Puszka,Marion Aribert,Alberto Dalla Mora,Henri Grateau,Antonio Pifferi

doi:10.1117/1.jbo.21.2.025004

Abstract

The noninvasive assessment of flap viability in autologous reconstruction surgery is still an unmet clinical need. To cope with this problem, we developed a proof-of-principle fully automatized setup for fast time-gated diffuse optical tomography exploiting Mellin-Laplace transform to obtain three-dimensional tomographic reconstructions of oxy- and deoxy-hemoglobin concentrations. We applied this method to perform preclinical tests on rats inducing total venous occlusion in the cutaneous abdominal flaps. Notwithstanding the use of just four source-detector couples, we could detect a spatially localized increase of deoxyhemoglobin following the occlusion (up to 550 μM in 54 min). Such capability to image spatio-temporal evolution of blood perfusion is a key issue for the noninvasive monitoring of flap viability.

Highlights

Reconstructive surgery aims to restore anatomical defects with autologous tissues called “flaps.” A flap includes the harvested tissues and their blood-supplying vessels which are essential for the flap survival
We showed that the use of a fast-gated single-photon avalanche diode (SPAD) coupled with a time-correlated single-photon counting (TCSPC) system permits to reach a dynamic range up to eight orders of magnitude[11], increasing retrieved information about deeper layers
In a previous work,[13] we presented a setup for diffuse optical tomography (DOT) based on fast-gated SPADs

Summary

Introduction

Reconstructive surgery aims to restore anatomical defects with autologous tissues called “flaps.” A flap includes the harvested tissues (skin, muscle, bone, etc., alone or combined) and their blood-supplying vessels (arteries and veins that constitute the pedicle) which are essential for the flap survival. In case of major reconstruction, the flap is completely separated from the donor site and the vessels are anastomosed (reconnected) to the vessels in the recipient site. The major complication of this type of surgery is thrombosis,[1] i.e., vessel obstruction by a clot (usually a venous one) and it can lead to flap failure (necrosis). Even if this complication is not frequent (between 3% to 7% depending on the surgeon’s experience and the type of flap2) the functional and esthetic consequences are dramatic if not treated rapidly. Salvage of the flap depends on the rapidity of restoration of the vessels permeability: 60% to 73% of complicated flaps could be salvaged if the thrombosis is treated before 6 h of evolution.[3]

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