Abstract:

Objective To evaluate the damage effect of glioma on corticospinal tract (CST) and motor function of lower extremities by using diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT).  Methods  A total of 45 patients with histopathologically confirmed gliomas (13 cases of low-grade gliomas and 32 cases of high-grade gliomas) were included in this pilot study. Motor cortex was not involved in all cases. Manual Muscle Testing (MMT) was used to measure contralateral muscle strength of knee joint. DTI images were used to measure the affected and contralateral posterior limb of internal capsule fractional anisotropy (FA) and relative FA (rFA, rFA = affected FA / contralateral FA). DTT images were used to measure affected and contralateral CST fiber density index (FDi) and relative FDi (rFDi, rFDi = affected FDi / contralateral FDi). Results In 45 patients, there were 6 cases (13.33% ) of MTT grade 2, 12 cases (26.67%) of grade 3, 21 cases (46.67%) of grade 4 and 6 cases (13.33%) of grade 5. All patients had different degrees of CST injury, including 21 cases (46.67%) of grade 1, 6 cases (13.33%) of grade 2 and 18 cases (40%) of grade 3. There were significant differences in the degree of CST injury (H = 38.560, P = 0.000), rFA (F = 37.453, P = 0.000) and rFDi (F = 6.734, P = 0.001) in different muscle strength groups. Among them, MTT grade 2 group had significantly higher degree of CST injury (Z = -4.088, P = 0.000; Z = -3.317, P = 0.001) and lower rFDi values (t = -3.850, P = 0.000; t = -3.481, P = 0.001) than MTT grade 4 and grade 5 groups, while had lower rFA values than MTT grade 3, grade 4 and grade 5 groups (t = -8.218, P = 0.000; t = -8.898, P = 0.000; t = -12.028, P = 0.000). Spearman rank correlation analysis showed that muscle strength was negatively correlated with CST injury (r_s = -0.840, P = 0.000) and positively correlated with rFA values of posterior limb of internal capsule (r_s = 0.615, P = 0.000) and rFDi (r_s = 0.567, P = 0.000). Conclusions The degree of CST injury in patients with glioma in CST area is related to the degree of motor dysfunction.

Key words: Glioma, Pyramidal tracts, Movement disorders, Magnetic resonance imaging

摘要：

目的 采用扩散张量成像（DTI）和扩散张量纤维束成像（DTT）评价胶质瘤对皮质脊髓束损害程度和下肢运动功能的影响。方法 共 45 例经病理学证实的皮质脊髓束区胶质瘤患者（包括低级别胶质瘤 13 例，高级别胶质瘤 32 例），均不伴运动皮质受累，徒手肌力测定（MTT）测定对侧膝关节肌力，DTI测量患侧和对侧内囊后肢部分各向异性（FA）值和相对部分各向异性（rFA）值，DTT 测量患侧和对侧皮质脊髓束纤维密度指数（FDi）和相对纤维密度指数（rFDi）。结果 45 例患者 MTT 分级 2 级 6 例（13.33%），3级 12例（26.67%），4级21例（46.67%），5级6例（13.33%）；均存在不同程度皮质脊髓束损害，1 级 21 例（46.67%）、2 级 6 例（13.33%）、3 级 18 例（40%）。不同肌力损害组皮质脊髓束损害程度（H = 38.560，P = 0.000）、rFA 值（F = 37.453，P= 0.000）和 rFDi值（F = 6.734，P = 0.001）差异均有统计学意义，其中 MTT 分级 2 级组皮质脊髓束损害程度高于（Z = -4.088，P = 0.000；Z = -3.317，P = 0.001）、rFDi 值低于（t = -3.850，P = 0.000；t = -3.481，P = 0.001）MTT 分级 4 级组和 MTT 分级 5 级组、rFA 值低于 MTT 分级 3 级组、MTT 分 级 4 级 组 和 MTT 分 级 5 级 组（t = -8.218，P = 0.000；t = -8.898，P = 0.000；t = -12.028，P =0.000）。Spearman 秩相关分析显示，肌力与皮质脊髓束损害程度呈负相关（r_s = -0.840，P = 0.000），与内囊后肢患侧和对侧 rFA 值（r_s = 0.615，P = 0.000）以及患侧和对侧 rFDi 值（r_s = 0.567，P = 0.000）呈正相关。结论 皮质脊髓束区胶质瘤患者皮质脊髓束损害程度与运动障碍相关。

关键词: 神经胶质瘤, 锥体束, 运动障碍, 磁共振成像