OBJECTIVE The objective of this study was the preclinical design and construction of a flexible intrasphenoid coil aiming for submillimeter resolution of the human pituitary gland. METHODS Sphenoid sinus measurements determined coil design constraints for use in > 95% of adult patients. Temperature safety parameters were tested. The 2-cm-diameter coil prototype was positioned in the sphenoid sinus of cadaveric human heads utilizing the transnasal endoscopic approach that is used clinically. Signal-to-noise ratio (SNR) was estimated for the transnasal coil prototype compared with a standard clinical head coil. One cadaveric pituitary gland was explanted and histologically examined for correlation to the imaging findings. RESULTS With the coil positioned directly atop the sella turcica at a 0° angle of the B0 static field, the craniocaudal distance (21.2 ± 0.8 mm) was the limiting constraint. Phantom experiments showed no detectable change in temperature at two sites over 15 minutes. The flexible coil was placed transnasally in cadaveric specimens using an endoscopic approach. The image quality was subjectively superior at higher spatial resolutions relative to that with the commercial 20-channel head coil. An average 17-fold increase in the SNR was achieved within the pituitary gland. Subtle findings visualized only with the transnasal coil had potential pathological correlation with immunohistochemical findings. CONCLUSIONS A transnasal radiofrequency coil feasibly provides a 17-fold boost in the SNR at 3 T. The ability to safely improve the quality of pituitary imaging may be helpful in the identification and subsequent resection of small functional pituitary lesions.

中文翻译：

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灵活的腔内 MRI 接收线圈，用于脑垂体的超高分辨率成像。

目的 本研究的目的是临床前设计和构建柔性蝶内线圈，旨在实现人类垂体的亚毫米分辨率。方法 蝶窦测量确定了适用于 > 95% 成年患者的弹簧圈设计限制。测试了温度安全参数。利用临床上使用的经鼻内窥镜方法将直径 2 厘米的线圈原型放置在人体尸体头部的蝶窦中。与标准临床头部线圈相比，估算了经鼻线圈原型的信噪比 (SNR)。取出一具尸体垂体并进行组织学检查，以检查其与影像学结果的相关性。结果 当线圈以 B0 静态场的 0° 角直接放置在蝶鞍顶部时，头尾距离 (21.2 ± 0.8 mm) 是限制约束。模型实验显示，15 分钟内两个地点的温度没有发生可检测到的变化。使用内窥镜方法将柔性线圈经鼻放置在尸体标本中。相对于商用 20 通道头部线圈，图像质量在更高的空间分辨率下主观上更优越。垂体内的 SNR 平均增加了 17 倍。仅通过经鼻线圈观察到的细微发现与免疫组织化学发现具有潜在的病理相关性。结论 经鼻射频线圈在 3 T 时可将 SNR 提高 17 倍。安全提高垂体成像质量的能力可能有助于识别和随后切除小的功能性垂体病变。