Bajwa Neha, Au Joshua, Jarrahy Reza, Sung Shijun, Fishbein Michael C, Riopelle David, Ennis Daniel B, Aghaloo Tara, St John Maie A, Grundfest Warren S, Taylor Zachary D
Department of Bioengineering, University of Los Angeles, California (UCLA), 410 Westwood Plaza, Los Angeles, CA 90025, USA.
Department of Head and Neck Surgery, UCLA, 200 Medical Plaza, Los Angeles, CA 90025, USA.
Biomed Opt Express. 2016 Dec 23;8(1):460-474. doi: 10.1364/BOE.8.000460. eCollection 2017 Jan 1.
Accurate and early prediction of tissue viability is the most significant determinant of tissue flap survival in reconstructive surgery. Perturbation in tissue water content (TWC) is a generic component of the tissue response to such surgeries, and, therefore, may be an important diagnostic target for assessing the extent of flap viability . We have previously shown that reflective terahertz (THz) imaging, a non-ionizing technique, can generate spatially resolved maps of TWC in superficial soft tissues, such as cornea and wounds, on the order of minutes. Herein, we report the first pilot study to investigate the utility of reflective THz TWC imaging for early assessment of skin flap viability. We obtained longitudinal visible and reflective THz imagery comparing 3 bipedicled flaps (i.e. survival model) and 3 fully excised flaps (i.e. failure model) in the dorsal skin of rats over a postoperative period of 7 days. While visual differences between both models manifested 48 hr after surgery, statistically significant ( 0.05, independent -test) local differences in TWC contrast were evident in THz flap image sets as early as 24 hr. Excised flaps, histologically confirmed as necrotic, demonstrated a significant, yet localized, reduction in TWC in the flap region compared to non-traumatized skin. In contrast, bipedicled flaps, histologically verified as viable, displayed mostly uniform, unperturbed TWC across the flap tissue. These results indicate the practical potential of THz TWC sensing to accurately predict flap failure 24 hours earlier than clinical examination.
准确且早期预测组织活力是重建手术中组织瓣存活的最重要决定因素。组织含水量（TWC）的扰动是组织对这类手术反应的一个通用组成部分，因此，可能是评估皮瓣活力程度的一个重要诊断靶点。我们之前已经表明，反射太赫兹（THz）成像作为一种非电离技术，能够在几分钟内生成角膜和伤口等浅表软组织中TWC的空间分辨图。在此，我们报告第一项初步研究，以探究反射太赫兹TWC成像在早期评估皮瓣活力方面的实用性。我们在术后7天内获取了纵向可见光和反射太赫兹图像，比较了大鼠背部皮肤的3个双蒂皮瓣（即存活模型）和3个完全切除的皮瓣（即失败模型）。虽然两种模型之间的视觉差异在术后48小时显现，但在太赫兹皮瓣图像集中，早在24小时就明显出现了TWC对比度的统计学显著（ 0.05，独立检验）局部差异。经组织学证实为坏死的切除皮瓣，与未受创伤的皮肤相比，皮瓣区域的TWC显著但局部降低。相比之下，经组织学验证为存活的双蒂皮瓣，在整个皮瓣组织中显示出大多均匀、未受扰动的TWC。这些结果表明太赫兹TWC传感具有实际潜力，能够比临床检查提前24小时准确预测皮瓣失败。
