磁共振成像在下肢深静脉血栓形成分期中的诊断价值

Diagnostic value of magnetic resonance imaging in staging of deep vein thrombosis of lower ;extremities

目的：使用磁共振直接成像（MRDTI）及直接增强MR下肢静脉成像（3D-CE-MRV）来评价下肢深静脉血栓形成的分型、分期，探讨其在下肢深静脉血栓形成诊断中的应用价值。方法2010年2月至2012年2月对55例在广州市番禺中心医院就诊并经数字减影血管造影（DSA）证实的下肢深静脉血栓形成的患者进行磁共振直接成像和直接增强MRV检查，MRDTI选用横断位SE T1WI、Tirm T2WI、真稳态进动快速成像（true FISP）；3D-CE-MRV采用三维扰相梯度回波T1WI序列（3D FLASH），并与DSA进行对比分析。结果下肢深静脉形成MRI表现急性期血栓31例，血管腔扩大，血管周围、肌间隙水肿，下肢软组织明显肿胀，与肌肉比较，血栓在T1WI上多表现为等或稍高信号，T2WI及true FISP序列上大多表现为稍高信号，直接增强MR下肢静脉成像表现为血管闭塞、中断或条状充盈缺损，周围少量或大量侧枝循环形成，其中中央型20例，周围型9例，混合型2例；慢性期血栓10例，血管腔无扩大表现，血管壁增厚且大多不规则，血管周围间隙无水肿，下肢软组织轻度肿胀或正常，与肌肉比较，血栓在T1WI、T2WI及true FISP序列上表现为等或低信号，直接增强MR下肢静脉成像表现为血管再通，血管腔细小，粗细不均，管壁毛糙，周围见侧枝循环形成；亚急性期血栓14例，表现介于急性期与慢性期之间，T1WI及T2WI血栓呈高信号，软组织肿胀减轻。以DSA为诊断标准，MRI诊断符合率为96.4%。结论磁共振直接成像（MRDTI）结合直接增强MR下肢静脉成像能准确评价下肢深静脉血栓形成的急慢性分期并能作出临床分型，为临床选择治疗方案提供依据。

Objective To evaluate the diagnostic value of the magnetic resonance direct thrombus imaging（MRDTI）and the three dimensional contrast enhanced MR venograph（3D-CE-MRV）in the typing and staging of deep vein thrombosis（DVT）of the lower extremities. Methods Fifty-five patients with DVT of the lower extremities hospitalized in Panyu Central Hospital of Guangzhou City and confirmed by digital subtraction angiography（DSA）between Feburuary 2010 and February 2012 were included as the subjects in the study,and underwent MRDTI and 3D-CE-MRV. MRDTI used spin echo T1-weight image（SE T1WI） sequence,turbo inversion recovery magnitude T2-weighted image （Tirm T2WI） sequence and true fast imaging with steady-state procesion（true FISP）sequence, whereas 3D-CE-MRV used three-dimensional fast low angle shot（3D FLASH）sequence. The findings of MRDTI and 3D-CE-MRV were compared with those of DSA. Results The MRI findings of the lower extremities DVT were found in 31 cases of acute thrombi,manifesting as dilated lumen of blood vessel,edema in peripheral blood vessels and intermuscular space,and significant swollen soft tissues of the lower extremities. Compared with the muscle,thrombus＆amp;nbsp;signal was iso- to mild hyperechoic in T1WI sequence,and muld hyperechoic in T2WI and true FISP sequences. On 3D-CE-MRV,vascular occlusion,interruption and strip-like filling defect with surrounding formation of collateral circulation were found,including 20 cases of central type,9 of peripheral type,and 2 of mixed type. Ten patients were found to have chronic thrombi. In these patients,no dilation of blood vessel lumen or edma in perivascular space was found. The blood vessel walls were thickened and mostly irregular. The soft tissues of the lower extremities were mildly swollen or normal. Compared with the muscle,iso- or hypoechoic signals of thrombus were found in T1WI,T2WI or true FISP sequences. On 3D-CE-MRV, vascular recanalization,small and uneven size of vessel lumen,coarse vessel wall,and collateral circulation in peripheral blood vessels were found. 14 cases of subacute thrombi were identified. The manifestations ranged between those of the acute and chronic thrombi,with high-intense thrombus signal in T1WI and T2WI,and lowered swelling in soft tissues. Based on the diagnostic criteria of DSA,the diagnostic accuracy of MRI was 96.4% Conclusion MRDTI and 3D-CE-MRV can accurately evaluate the acute and chronic staging and typing of the DVT in the lower extremities,providing evidence for clinical diagnosis and treatment. signal was iso- to mild hyperechoic in T1WI sequence,and muld hyperechoic in T2WI and true FISP sequences. On 3D-CE-MRV,vascular occlusion,interruption and strip-like filling defect with surrounding formation of collateral circulation were found,including 20 cases of central type,9 of peripheral type,and 2 of mixed type. Ten patients were found to have chronic thrombi. In these patients,no dilation of blood vessel lumen or edma in perivascular space was found. The blood vessel walls were thickened and mostly irregular. The soft tissues of the lower extremities were mildly swollen or normal. Compared with the muscle,iso- or hypoechoic signals of thrombus were found in T1WI,T2WI or true FISP sequences. On 3D-CE-MRV, vascular recanalization,small and uneven size of vessel lumen,coarse vessel wall,and collateral circulation in peripheral blood vessels were found. 14 cases of subacute thrombi were identified. The manifestations ranged between those of the acute and chronic thrombi,with high-intense thrombus signal in T1WI and T2WI,and lowered swelling in soft tissues. Based on the diagnostic criteria of DSA,the diagnostic accuracy of MRI was 96.4% Conclusion MRDTI and 3D-CE-MRV can accurately evaluate the acute and chronic staging and typing of the DVT in the lower extremities,providing evidence for clinical diagnosis and treatment.