Wang Lili, Lv Peng, Yang Shuohui, Zeng Mengsu, Lin Jiang
Department of Diagnostic Radiology, Shanghai Zhongshan Hospital, Shanghai Medical College of Fudan University and Shanghai Institute of Medical Imaging, Shanghai 200032, China.
Department of Radiology, Xiehe Hospital, Fujian Medical University, Fujian 350001, China.
J Thorac Dis. 2017 Jun;9(6):1624-1633. doi: 10.21037/jtd.2017.06.38.
Preoperative assessment of the integrity of major thoracic vessels in central bronchogenic carcinoma is vital for tumor staging and treatment planning. Contrast-enhanced CT is currently the first choice of modality for this purpose in clinical practice with limitations including exposure to ionizing radiation and the use of iodinated contrast material. MRI has been increasingly employed for the staging of lung cancer. More recently, unenhanced magnetic resonance angiography (MRA) which is totally non-invasive and contrast-free has been reported able to show thoracic vessels. This study was to compare image qualities of three unenhanced-MRAs and to evaluate accuracy of them in assessing thoracic vessel invasion by using contrast-enhanced CT as a reference standard.
A total of 30 patients with central bronchogenic carcinoma confirmed by pathology were examined by CT and unenhanced MRA including 2D free-breathing (FB)-TrueFISP, breath-holding (BH)-TrueFISP and 3D respiratory-triggered (RT)-SPACE. Image qualities of pulmonary arteries and veins, thoracic aorta and vena cava were scored for each MRA sequence. Vessel to lung tissue signal contrast-to-noise ratio (CNR), vessel to tumor signal contrast ratio (VTR), and tumor to background signal contrast ratio (TBR) were calculated. On each method, vessel invasion was evaluated according to types of morphological relationships between the tumor and major vessels.
The three MRAs showed no significant difference in CNR (P=0.518) while TrueFISP MRAs were better than SPACE in terms of VTR (P=0.000) and image quality (P=0.002). Excellent consistency with CT was found for all three MRAs in assessment of the morphological relationships between tumors and major vessels (FB-TrueFISP: kappa =0.821; BH-TrueFISP: kappa =0.862; RT-SPACE: kappa =0.811).
Both TrueFISP and SPACE allow satisfactory visualization of major mediastinal and hilar vessels and are comparable to MDCT in assessment of vessel invasion in patients with central lung cancer. TrueFISP sequences are better than SPACE in regard to image quality and VTR.
中央型支气管肺癌主要胸段血管完整性的术前评估对于肿瘤分期和治疗方案规划至关重要。在临床实践中，对比增强CT目前是用于此目的的首选检查方式，但存在包括暴露于电离辐射和使用碘化对比剂等局限性。MRI已越来越多地用于肺癌分期。最近，有报道称完全无创且无需对比剂的非增强磁共振血管造影（MRA）能够显示胸段血管。本研究旨在比较三种非增强MRA的图像质量，并以对比增强CT作为参考标准评估它们在评估胸段血管侵犯方面的准确性。
对30例经病理确诊的中央型支气管肺癌患者进行CT和非增强MRA检查，包括二维自由呼吸（FB）-TrueFISP、屏气（BH）-TrueFISP和三维呼吸触发（RT）-SPACE。对每个MRA序列的肺动脉、肺静脉、胸主动脉和腔静脉的图像质量进行评分。计算血管与肺组织的信号对比噪声比（CNR）、血管与肿瘤的信号对比率（VTR）以及肿瘤与背景的信号对比率（TBR）。在每种方法上，根据肿瘤与主要血管之间形态学关系的类型评估血管侵犯情况。
三种MRA的CNR无显著差异（P=0.518），而TrueFISP MRA在VTR（P=0.000）和图像质量（P=0.002）方面优于SPACE。在评估肿瘤与主要血管之间的形态学关系时，三种MRA与CT均具有极好的一致性（FB-TrueFISP：kappa=0.821；BH-TrueFISP：kappa=0.862；RT-SPACE：kappa=0.811）。
TrueFISP和SPACE均能令人满意地显示主要纵隔和肺门血管，在评估中央型肺癌患者的血管侵犯方面与多层螺旋CT相当。TrueFISP序列在图像质量和VTR方面优于SPACE。
