Development of a newly designed surface coil for maxillofacial MR imaging

磁共振成像是一种重要的诊断手段，在颌面部病变的诊断中，需要大面积成像并保持良好的图像质量。特别是在对恶性肿瘤进行增强扫描时，需要在不更换接收线圈的情况下同时对眶下至锁骨上区域进行扫描。该线圈基本上由三个矩形线圈组成。第一个矩形环是对称的，覆盖两个眉毛到耳朵，然后在胸锁乳突肌上运行，并在胸锁关节处连接。第二、三线圈分别与第一线圈相连，覆盖腮腺两侧，将线圈连接到含硫酸铜溶液的人体型丙烯酸体模上，获得42幅经眼眶至胸锁关节的轴向横断图像。根据体模矢状面图像的信号强度，对每幅图像进行标定，评价其空间信号强度分布，并与传统的头部线圈和颈部线圈进行比较，结果表明，新线圈能够提供足够的颌面部成像质量。

Magnetic resonance imaging is becoming an essential diagnostic modality in recognizing the extent and nature of the lesion.In the diagnosis of maxillofacial lesions, wide area imaging is required with keeping good image quality. Especially when contrast enhancement is applied in malignancies, region including infraorbital to supraclavicular area should be taken simultaneously without changing receiver coils.In this investigation, a new surface coil suitable for the maxillofacial imaging was developed. Distribution of signal intensity in the head and nack region was also evaluated.This coil is basically consisted of three rectangular loops. The first rectangular loop is symmetric, covers both eyebrows to ears, then runs on sternocleidomastoid muscles and joins at sternoclavicular joint. The second and third loops are attached to the first loop and covers both parotid glands.For the evaluation of the signal intensities, the coil was attached to a human body shaped acrylic phantom containing copper sulfate solution and 42 axial transverse images through orbit to sternoclavicular joint was obtained. Based on the signal intensity in the sagittal image of the phantom, each image was calibrated and spatial signal intensity distribution was evaluated.The conventional head coil and neck coil were also evaluated by the same way for the comparison.As a result the new coil gave sufficient quality for the maxillofacial imaging.