New Ultrasound Instrument for Carotid Screening

描述（由申请人提供）：该计划的目标是减少中风的发生。在80%的病例中，这种致残的主要原因和第三大死亡原因毫无征兆地发生；发现并纠正导致中风的条件可以预防中风。至少50%的中风是由颈动脉分叉处的斑块引起的。从有明显颈动脉狭窄的无症状患者身上去除斑块（“颈动脉内膜切除术”），在接下来的五年里，可以将他们的中风发病率降低近三倍。这是减少中风发生的极好方法。不幸的是，使用传统的通用双多普勒超声仪器在引起中风之前进行筛查发现这个重要的斑块太昂贵了，不合理；这些超声仪器需要熟练的超声技师和熟练的医生才能有效地工作。我们的目标是实现一种特殊用途的超声仪器，专门为颈动脉筛查设计，用于初级保健办公室，作为一种快速而廉价的发现颈动脉狭窄的方法，并将其指导给专家进行纠正。在“概念验证”阶段，我们开发并构建了这种特殊用途仪器，并表明它对发现显著的颈动脉狭窄具有很高的敏感性和特异性。检查只需要几分钟，非专业人员很快就学会了使用仪器，仪器的成本只有几千美元。在第二阶段，建议对这种筛选进行试点研究。使用第一阶段仪器的改进版本，四到六个初级保健医生办公室将配备颈动脉筛查系统，并指导护士使用该系统。医生将邀请合适的患者，年龄在60岁以上，至少有一个额外的危险因素，使用该设备进行筛查，发现颈动脉狭窄的患者将被引导到中央认证的非侵入性血管实验室进行常规双多普勒检查。来自1400名患者的数据，以统计显著性所需的数字计算，将显示这种两步筛查系统是否具有成本效益；成本效益将由适合该筛选的马尔可夫模型确定，该模型将作为本研究的一部分开发。

DESCRIPTION (provided by applicant): The goal of this program is to reduce the occurrence of stroke. This leading cause of disability, and third leading cause of death, strikes without warning in 80% of cases; finding and correcting the conditions that lead to stroke can prevent stroke. At least 50% of strokes arise from plaque at the carotid bifurcation. Removing plaque (a "carotid endarterectomy") from asymptomatic patients who have significant carotid stenoses reduces their stroke rate over the next five years by a factor of almost three. This is an excellent way of reducing the occurrence of stroke. Unfortunately, screening to find this significant plaque before it causes stroke, using conventional, general-purpose duplex Doppler ultrasound instruments, is too expensive to justify; these ultrasound instruments require a skilled sonographer and skilled physician to be effective. Realization of a special-purpose ultrasound instrument, specifically designed for carotid screening and meant for use in primary-care offices as a quick and inexpensive means of finding carotid stenoses and directing them to specialists to correct, is our aim. In the "proof-of-concept" Phase I of this SBIR we developed and built such as special purpose instrument, and showed that it had high sensitivity and specificity for finding significant carotid stenoses. The examinations required only a few minutes, nonspecialists learned to use the instrument quickly, and the cost of the instrument was only a few thousand dollars. In Phase II, a pilot study of such screening is proposed. Using an improved version of the Phase I instrument, four to six primary care physician offices will be equipped with the carotid screening system and nurses instructed in its use. Physicians will invite appropriate patients, those aged 60+ with at least one additional risk factor, to be screened with the device, and those found with carotid stenoses will be directed to a central certified non-invasive vascular laboratory for conventional duplex Doppler examination. The data from 1400 patients, calculated as the number required for statistical significance, will show whether this two-step screening system is (or is not) cost-effective; the cost-effectiveness will be determined by a Markov model appropriate to this screening that will be developed as part of this research.