MRI with microscopy coil of the proximal interphalangeal joints: preliminary study

Objective To investigate the use of a microscopy coil in MR examination of proximal interphalangeal joints (PIJ) to collect evidence on micro-anatomical pathological changes for further MR diagnosis. Methods Four PIJ in cadaver and 12 PIJ from 7 normal volunteers were scanned with a microscopy surface coil (23 nun in diameter) at 1.5 T MRI. Sagittal T1-weighted images were also obtained with a conventional surface coil using the same parameters for the volunteers. Based on the observation of sagittal,traverse, coronal PIJ imaging features of cadaver, the optimized sequences were chosen for the volunteer's application. Image quality of the PIJ structures from volunteers was analyzed by two radiologists on a 5-point scale (0, nonvisualization;1, poor;2, average;3, good;4, excellent) and compared with Wilcoxon signed rank test between the microscopy and C3 surface coil in sagittal direction. Results With microscopy coil all sequences can visualize the main structures of PIJ, and all the PIJ images were classified as good or excellent except for one as average, while all the 12 PIJ with C3 coil were classified as poor or invisible. PIJ structures (proximal phalanx head, middle phalanx base, cartilage, volar plate) from volunteers show higher scores of quality with microscopy coils than those with C3 coil, and the difference was significant (Z=-3.274, -3.274, -3.213,and-3.742 respectively, all P<0. O1). Conclusion High-resolution MRI of the normal PIJ with microscopy coil was superior to those with a conventional surface coil,and it can be a promising method to diagnose interphalangeal joints lesions. Key words: Finger joint; Magnetic resorrance imaging; Anatomical comparision