磁共振成像在法洛四联症术后随访中的应用价值

摘要

Objective To investigate the application of magnetic resonance imaging (MRI) in the follow-up after surgery for tetralogy of Fallot (TOF). Methods Seventy-one patients were examined with MRI during follow up after surgery for TOF, and the scanning sequences included fast imaging employing steady-state acquisition (FIESTA), phase-contrast magnetic resonance imaging ( PCMR) and contrast enhanced magnetic resonance angiography (CE-MRA). Results Branch pulmonary artery stenosis was detected by CE-MRA in 44 of 71 (62.0%) patients, including left pulmonary artery stenosis ( n = 29, 40. 8% ) , righi pulmonary artery stenosis ( n =4, 5. 6% ) and both left and right pulmonary artery stenosis (n = ll, 15.5%). With FIESTA sequence, right ventricular end-diastolic volume was measured at (115. 28 ± 15.18) mL/m2. Varied amount of pulmonary regurgitation (42. 12% ± 16. 30%) occurred in all 38 cases with PCMR. Meanwhile, serious pulmonary regurgitation was observed in 14 cases (36.8%), with pulmonary artery regurgitant fraction >40%. In patients without branch pulmonary artery stenosis, regurgitant fraction of the left pulmonary artery (57. 70% ±21. 99%) was significantly higher than that of the right pulmonary artery (30.32% ± 13. 44% ) ( P <0. 01). Delayed onset of the tricuspid valve flow was observed by PCMR in 18 (54. 5%) of 33 patients. However, there was no significant difference in the pulmonary artery regurgitant fraction, right ventricular ejection fraction and right ventricular end-diastolic volume index between patients with and without delayed onset of the tricuspid valve flow (P > 0. 05). Conclusion Left pulmonary stenosis, pulmonary regurgitation and right ventricular enlargement are common complications after surgery for TOF. MRI can provide adequate information on residual anatomical problems and functional evaluation, which makes it ideally suited to the evaluation of patients after surgery for TOF.%目的 评价磁共振成像(MRI)在法洛四联症(TOF)术后随访中的应用价值.方法 在71例TOF根治术后患者的随访中应用MRI进行检查,扫描序列包括真稳态进动快速成像序列(HESTA)、相位对比技术(PCMR)和血管增强(CE-MRA).结果 71例患者中,CE-MRA诊断肺动脉分支狭窄44例(62.0％),其中左肺动脉狭窄29例(40.8％),右肺动脉狭窄4例(5.6％),同时伴有左肺动脉和右肺动脉狭窄11例(15.5％).FIESTA序列测得右心室舒张末期容积为(115.28±15.18) mL/m2.38例应用PCMR法测量肺动脉血流的患者均存在肺动脉瓣反流,反流分数为(42.12±16.30)％,其中14例(36.8％)肺动脉重度反流(反流分数＞40％)；在无肺动脉分支狭窄患者中,左肺动脉的反流分数明显高于右肺动脉[ (57.70±21.99)％vs(30.32±13.44)％](P＜0.01).33例患者的二尖瓣和三尖瓣血流测量应用PCMR法,结果 有18例(54.5％)存在三尖瓣开放延迟于二尖瓣；但三尖瓣开放延迟和无三尖瓣开放延迟患者中,在肺动脉瓣反流分数、右心室舒张末期容积和射血分数上差异均无统计学意义(P＞0.05).结论 左肺动脉狭窄、肺动脉瓣反流和右心室扩大是TOF术后常见的并发症.MRI不仅可准确诊断TOF术后残余解剖畸形,还能提供全面的心功能及血流动力学信息,重复性好,是TOF术后随访中理想的影像学诊断方法.