MRI active guidewire with an embedded temperature probe and providing a distinct tip signal to enhance clinical safety.
MRI active guidewire with an embedded temperature probe and providing a distinct tip signal to enhance clinical safety.
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DOI：
10.1186/1532-429x-14-38
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发表时间：
2012-06-21
期刊：
影响因子：
--
通讯作者：
Kocaturk O
中科院分区：
文献类型：
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作者：
Sonmez M;Saikus CE;Bell JA;Franson DN;Halabi M;Faranesh AZ;Ozturk C;Lederman RJ;Kocaturk O
由于缺乏安全和显眼的主动导丝，心血管介入性磁共振成像领域受到了阻碍。导电导丝的加热在体内很难预测，而且使用外部探头测量也是破坏性的。我们描述了一种临床级0.035英寸(0.89 mm)导丝，用于1.5 T的磁共振右心和左心导管术，该导丝具有实时监测温度的内部探头，具有尖端和竖直的可见性以及适当的灵活性。该设计有一个内部光纤温度探头，以及一个远端螺线管，以增强无环天线的尖端可见性。我们测试了不同的针尖螺线管配置，以平衡加热和信号分布。我们在体外和体内测试了力学性能，并与临床上流行的镍钛合金导丝进行了比较。螺线管将最大加热点(“热点”)从尖端移到更近的位置，在那里可以测量，而不会损害导丝的弯曲。探头回撤允许创建纵向导丝温度图，从而允许快速评估设计原型。仅远端螺线管附件在针尖可见性和加热之间提供了设计候选之间的最佳折衷。当固定在热点时，内部探头一致地反映了与外部探头相比的最高温度。在猪左心导管术中进行实时体温监测。使用正常操作参数(翻转角度，45°；SAR1.01 W/kg)时，加热可以忽略不计；只有在高射频功率模式(翻转角度，90°；SAR3.96 W/kg)下，温度才会增加4.2C，并且只有当导丝通过导入器护套与血液冷却效果隔离时，温度才会增加4.2C。最终的导丝设计的尖端灵活性和活体性能与流行的商业导丝相似。我们在一根0.035英寸的核磁共振导丝中集成了一个光纤温度探测器。实时监测有助于检测使用过程中的有害发热，而不会损害机械导丝的操作，也不会损害MRI的可见性。因此，我们不需要依靠预测来确保临床操作的安全。未来的实现可能会基于温度反馈来调制特定吸收率(SAR)。
The field of interventional cardiovascular MRI is hampered by the unavailability of active guidewires that are both safe and conspicuous. Heating of conductive guidewires is difficult to predict in vivo and disruptive to measure using external probes. We describe a clinical-grade 0.035” (0.89 mm) guidewire for MRI right and left heart catheterization at 1.5 T that has an internal probe to monitor temperature in real-time, and that has both tip and shaft visibility as well as suitable flexibility. The design has an internal fiberoptic temperature probe, as well as a distal solenoid to enhance tip visibility on a loopless antenna. We tested different tip-solenoid configurations to balance heating and signal profiles. We tested mechanical performance in vitro and in vivo in comparison with a popular clinical nitinol guidewire. The solenoid displaced the point of maximal heating (“hot spot”) from the tip to a more proximal location where it can be measured without impairing guidewire flexion. Probe pullback allowed creation of lengthwise guidewire temperature maps that allowed rapid evaluation of design prototypes. Distal-only solenoid attachment offered the best compromise between tip visibility and heating among design candidates. When fixed at the hot spot, the internal probe consistently reflected the maximum temperature compared external probes. Real-time temperature monitoring was performed during porcine left heart catheterization. Heating was negligible using normal operating parameters (flip angle, 45°; SAR, 1.01 W/kg); the temperature increased by 4.2°C only during high RF power mode (flip angle, 90°; SAR, 3.96 W/kg) and only when the guidewire was isolated from blood cooling effects by an introducer sheath. The tip flexibility and in vivo performance of the final guidewire design were similar to a popular commercial guidewire. We integrated a fiberoptic temperature probe inside a 0.035” MRI guidewire. Real-time monitoring helps detect deleterious heating during use, without impairing mechanical guidewire operation, and without impairing MRI visibility. We therefore need not rely on prediction to ensure safe clinical operation. Future implementations may modulate specific absorption rate (SAR) based on temperature feedback.