Banahan Caroline, Rogerson Zach, Rousseau Clément, Ramnarine Kumar V, Evans David H, Chung Emma M L
Medical Physics Department, University Hospitals of Leicester NHS Trust, Leicester, UK.
Department of Physics, University of Leicester, Leicester, UK.
Ultrasound Med Biol. 2014 Nov;40(11):2642-54. doi: 10.1016/j.ultrasmedbio.2014.06.003. Epub 2014 Sep 11.
The ability to distinguish harmful solid cerebral emboli from gas bubbles intra-operatively has potential to direct interventions to reduce the risk of brain injury. In this in vitro study, two embolus discrimination techniques, dual-frequency (DF) and frequency modulation (FM) methods, are simultaneously compared to assess discrimination of potentially harmful large pieces of carotid plaque debris (0.5-1.55 mm) and thrombus-mimicking material (0.5-2 mm) from gas bubbles (0.01-2.5 mm). Detection of plaque and thrombus-mimic using the DF technique yielded disappointing results, with four out of five particles being misclassified (sensitivity: 18%; specificity: 89%). Although the FM method offered improved sensitivity, a higher number of false positives were observed (sensitivity: 72%; specificity: 50%). Optimum differentiation was achieved using the difference between peak embolus/blood ratio and mean embolus/blood ratio (sensitivity: 77%; specificity: 81%). We conclude that existing DF and FM techniques are unable to confidently distinguish large solid emboli from small gas bubbles (<50 μm).
术中区分有害的固体脑栓子与气泡的能力，有可能指导采取干预措施以降低脑损伤风险。在这项体外研究中，同时比较了两种栓子鉴别技术，即双频（DF）和调频（FM）方法，以评估能否区分潜在有害的大块颈动脉斑块碎片（0.5 - 1.55毫米）及模拟血栓物质（0.5 - 2毫米）与气泡（0.01 - 2.5毫米）。使用DF技术检测斑块和模拟血栓得到的结果令人失望，五分之四的颗粒被误分类（灵敏度：18%；特异性：89%）。尽管FM方法的灵敏度有所提高，但观察到的假阳性数量更多（灵敏度：72%；特异性：50%）。使用栓子/血液峰值比率与栓子/血液平均比率之间的差值可实现最佳区分（灵敏度：77%；特异性：81%）。我们得出结论，现有的DF和FM技术无法可靠地区分大的固体栓子与小气泡（<50微米）。
