Sato Junko, Ishii Yoshinori, Noguchi Hideo, Toyabe Shin-Ichi
Ishii Orthopaedic and Rehabilitation Clinic, 1089 Shimo-Oshi, Gyoda, Saitama, 361-0037, Japan.
Division of Information Science and Biostatistics, Niigata University Graduate School of Medical and Dental Sciences, 1 Asahimachi Dori, Niigata, Niigata, 951-8520, Japan.
BMC Med Imaging. 2015 Mar 15;15:9. doi: 10.1186/s12880-015-0051-6.
The disarranged fat stripe of the pronator quadratus muscle (PQ) on radiographs (the PQ sign) is reported to be predictive of subtle bone fractures. This study aimed to report the results of magnetic resonance imaging (MRI) study in the patients in whom bone injury was not radiographically detected around the wrist joint, and the PQ was sonographically swollen following acute trauma.
We evaluated sonographically the PQ of 55 patients who showed normal radiographs following acute trauma. The sonographic appearance of the PQ was checked on both longitudinal and transverse images. On the longitudinal image, the probe was positioned along the flexor carpi radialis tendon. For the transverse image, we adopted the image of the same level in which the PQ of the unaffected hand showed maximal thickness. The PQ was considered to be swollen with disproportionate hyperechogenicity and/or thickening compared with the unaffected side at least in one of the two images. Of the 55 patients, 25 patients whose PQ was considered to be swollen underwent MRI study. PQ thickness in millimeters was retrospectively measured on longitudinal and transverse sonographic images.
Twenty-three patients (92.0%) had occult bone injury, and two adult patients (8.0%) showed only wrist joint effusion on MRI. Among these 23, the distal radius was the most frequent location of the occult bone injury (20 patients; 9 [36.0%] with an occult fracture line and 11 [44.0%] with bone bruising). In longitudinal image, the mean value of the PQ thickness of affected hands was 6.2 (3.7-9.6 mm; standard deviation [SD], 1.5) and that of unaffected hands was 4.5 (2.3-6.7 mm; SD, 1.2), respectively. In transverse image, that of dominant and nondominant hands was 7.6 (4.6-13.2 mm; SD, 2.0) and 5.5 (3.6-7.5 mm; SD, 1.1), respectively. The mean difference in PQ thickness between affected and unaffected hands was 1.7 (0.1-5.0 mm; SD, 1.1) in longitudinal image and 2.0 (0.3-6.8 mm; SD, 1.7) in transverse image.
Sonographic swelling of the PQ might be indicative of occult bone injury in patients with normal radiographs following acute trauma.
据报道，X线片上旋前方肌（PQ）脂肪条纹紊乱（PQ征）可预测细微骨折。本研究旨在报告磁共振成像（MRI）对急性创伤后腕关节周围X线未检出骨损伤但PQ超声显示肿胀患者的检查结果。
我们对55例急性创伤后X线片正常的患者进行了PQ超声检查。在纵、横断面上检查PQ的超声表现。在纵断面上，探头沿桡侧腕屈肌腱放置。对于横断面图像，我们采用未受影响手的PQ显示最大厚度的同一水平图像。如果在两张图像中的至少一张上，PQ与未受影响侧相比出现不成比例的高回声和/或增厚，则认为PQ肿胀。55例患者中，25例PQ被认为肿胀的患者接受了MRI检查。在纵、横断面上回顾性测量PQ厚度（单位：毫米）。
23例患者（92.0%）存在隐匿性骨损伤，2例成年患者（8.0%）MRI仅显示腕关节积液。在这23例患者中，桡骨远端是隐匿性骨损伤最常见的部位（20例患者；9例[36.0%]有隐匿性骨折线，11例[44.0%]有骨挫伤）。在纵断面上，患侧手PQ厚度的平均值为6.2（3.7 - 9.6毫米；标准差[SD]，1.5），未受影响侧手为4.5（2.3 - 6.7毫米；SD，1.2）。在横断面上，优势手和非优势手的PQ厚度分别为7.6（4.6 - 13.2毫米；SD，2.0）和5.5（3.6 - 7.5毫米；SD，1.1）。患侧与未受影响侧手PQ厚度的平均差值在纵断面上为1.7（0.1 - 5.0毫米；SD，1.1），在横断面上为2.0（0.3 - 6.8毫米；SD，1.7）。
急性创伤后X线片正常的患者，PQ超声肿胀可能提示隐匿性骨损伤。
