Department of Rehabilitation Medicine, Yeouido St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
Department of Rehabilitation Medicine, Hankook-hyo Convalescent Hospital, Republic of Korea.
Neuroimage Clin. 2022;35:103103. doi: 10.1016/j.nicl.2022.103103. Epub 2022 Jun 27.
Swallowing impairment after stroke may be related to the state of the corticobulbar tract (CBT), which is the motor projection fiber responsible for deglutition, but evidence is still lacking regarding which parameter could relate to poststroke swallowing recovery as measured by videofluroscope findings. This prospective study evaluated diffusion tensor imaging (DTI) parameters among dysphagic stroke patients compared with those of nondysphagia stroke patients and age-matched healthy subjects and followed swallowing recovery in dysphagic patients as assessed with the Modified Barium Swallow Impairment Profile (MBSImP©).
Diffusion tractography was performed in 69 subjects, consisting of 27 S patients with dysphagia, 18 healthy subjects and 24 S patients with no evidence of dysphagia. DTI was performed within 14 days of stroke onset. Follow-up DTI was performed in the dysphagic group at three months. The tract volume (TV) of the CBT and frontal operculum as determined by fractional anisotropy (FA) was compared among the 3 groups. Correlations of these parameters with initial dysphagia severity and swallowing parameters at baseline and 3 months postonset were assessed.
All stroke patients showed lower CBT TV on the affected and unaffected sides than those in the control group, even in those who showed no evidence of clinical dysphagia. The dysphagia group showed a greater reduction in CBT TV on the affected side (P < 0.001). Receiver operating characteristic analysis showed that cutoff values of 4.1 cm for TV and 0.24 for FA from the affected side could classify dysphagia with good accuracy (AUC = 0.77, 0.75, respectively) and specificity levels. FA values in the unaffected frontal operculum showed a significant correlation (rho = -0.40, P = 0.02) with swallowing outcome as observed by the total scores of MBSImP©. In addition, these values proved to be significant variables to predict swallowing outcome in multiple regression analysis (R = 0.6317, adjR = 0.5815, F = 12.58, p < 0.001, AIC = 203.65).
Even when clinical dysphagia is not apparent, individuals with a supratentorial stroke may show reduced CBT parameters compared to healthy controls. Supratentorial stroke may manifest with dysphagia if a certain extent of CBT volume and white matter tract integrity is involved, with a greater degree of CBT injury in the affected sides determining poststroke dysphagia severity. In contrast, recovery was independent of the affected parameters, and an initial lower FA value in the unaffected frontal operculum was indicative of a poorer 3-month dysphagia outcome. DTI parameters obtained within two weeks of stroke onset may help classify those with dysphagia, predict recovery and help plain therapeutic strategies to maintain the adaptive role of the white matter tract, which is crucial in swallowing recovery.
脑卒中后吞咽障碍可能与皮质延髓束（CBT）状态有关，CBT 是负责吞咽的运动投射纤维，但仍缺乏证据表明哪种参数可以与视频荧光镜检查结果评估的脑卒中后吞咽恢复相关。本前瞻性研究比较了吞咽障碍脑卒中患者与无吞咽障碍脑卒中患者和年龄匹配的健康对照组之间的弥散张量成像（DTI）参数，并通过改良吞咽障碍评估量表（MBSImP©）评估吞咽障碍患者的吞咽恢复情况。
对 69 名受试者进行了扩散张量成像，其中包括 27 名吞咽障碍脑卒中患者、18 名健康受试者和 24 名无吞咽障碍脑卒中患者。DTI 在脑卒中发作后 14 天内进行。吞咽障碍组在三个月时进行随访 DTI。比较 3 组患者的 CBT 和额部岛盖的部分各向异性（FA）的束容积（TV）。评估这些参数与初始吞咽障碍严重程度以及基线和脑卒中发作后 3 个月的吞咽参数之间的相关性。
所有脑卒中患者的患侧和健侧 CBT TV 均低于对照组，即使在无临床吞咽障碍的患者中也是如此。吞咽障碍组患侧 CBT TV 下降更明显（P < 0.001）。受试者工作特征分析显示，患侧 TV 为 4.1cm 和 FA 为 0.24 时可以很好地准确（AUC=0.77、0.75）分类吞咽障碍，并具有较高的特异性水平。未受累侧额部岛盖的 FA 值与 MBSImP©的总评分观察到的吞咽结局呈显著相关性（rho=-0.40，P=0.02）。此外，这些值在多元回归分析中是预测吞咽结局的显著变量（R=0.6317，adjR=0.5815，F=12.58，p<0.001，AIC=203.65）。
即使没有明显的临床吞咽障碍，幕上脑卒中患者的 CBT 参数也可能低于健康对照组。如果 CBT 体积和白质束完整性的一定程度受到影响，幕上脑卒中可能会表现为吞咽障碍，患侧 CBT 损伤程度更大决定脑卒中后吞咽障碍的严重程度。相反，恢复与受累参数无关，未受累侧额部岛盖的初始 FA 值较低预示着 3 个月时吞咽障碍结局较差。脑卒中发作后两周内获得的 DTI 参数可有助于对吞咽障碍进行分类，预测恢复情况，并有助于制定简单的治疗策略以维持白质束的适应性作用，这对吞咽恢复至关重要。
