Nandlall Sacha D, Goldklang Monica P, Kalashian Aubrey, Dangra Nida A, D'Armiento Jeanine M, Konofagou Elisa E
Department of Biomedical Engineering, Columbia University, New York, New York, USA.
Department of Medicine, Columbia University, New York, New York, USA.
Ultrasound Med Biol. 2014 Oct;40(10):2404-14. doi: 10.1016/j.ultrasmedbio.2014.04.013. Epub 2014 Aug 15.
The abdominal aortic aneurysm (AAA) is a silent and often deadly vascular disease caused by the localized weakening of the arterial wall. Previous work has indicated that local changes in wall stiffness can be detected with pulse wave imaging (PWI), which is a non-invasive technique for tracking the propagation of pulse waves along the aorta at high spatial and temporal resolutions. The aim of this study was to assess the capability of PWI to monitor and stage AAA progression in a murine model of the disease. ApoE/TIMP-1 knockout mice (N = 18) were given angiotensin II for 30 days via subcutaneously implanted osmotic pumps. The suprarenal sections of the abdominal aortas were imaged every 2-3 d after implantation using a 30-MHz VisualSonics Vevo 770 with 15-μm lateral resolution. Pulse wave propagation was monitored at an effective frame rate of 8 kHz by using retrospective electrocardiogram gating and by performing 1-D cross-correlation on the radiofrequency signals to obtain the displacements induced by the waves. In normal aortas, the pulse waves propagated at constant velocities (2.8 ± 0.9 m/s, r(2) = 0.89 ± 0.11), indicating that the composition of these vessels was relatively homogeneous. In the mice that developed AAAs (N = 10), the wave speeds in the aneurysm sac were 45% lower (1.6 ± 0.6 m/s) and were more variable (r(2) = 0.66 ± 0.23). Moreover, the wave-induced wall displacements were at least 80% lower within the sacs compared with the surrounding vessel. Finally, in mice that developed fissures (N = 5) or ruptures (N = 3) at the sites of their AAA, higher displacements directed out of the lumen and with no discernible wave pattern (r(2) < 0.20) were observed throughout the cardiac cycle. These findings indicate that PWI can be used to distinguish normal murine aortas from aneurysmal, fissured and ruptured ones. Hence, PWI could potentially be used to monitor and stage human aneurysms by providing information complementary to standard B-mode ultrasound.
腹主动脉瘤（AAA）是一种由动脉壁局部变薄引起的隐匿且常致命的血管疾病。先前的研究表明，壁僵硬度的局部变化可以通过脉搏波成像（PWI）检测到，这是一种以高空间和时间分辨率追踪脉搏波沿主动脉传播的非侵入性技术。本研究的目的是评估PWI在疾病小鼠模型中监测和分期AAA进展的能力。通过皮下植入渗透泵，给载脂蛋白E/基质金属蛋白酶组织抑制因子-1基因敲除小鼠（N = 18）注射血管紧张素II 30天。植入后，每隔2 - 3天使用具有15μm横向分辨率的30MHz VisualSonics Vevo 770对腹主动脉的肾上腺段进行成像。通过回顾性心电图门控并对射频信号进行一维互相关以获得波引起的位移，以8kHz的有效帧率监测脉搏波传播。在正常主动脉中，脉搏波以恒定速度传播（2.8±0.9m/s，r² = 0.89±0.11），表明这些血管的成分相对均匀。在发生AAA的小鼠（N = 10）中，瘤腔内的波速降低了45%（1.6±0.6m/s）且变化更大（r² = 0.66±0.23）。此外，与周围血管相比，瘤腔内波引起的壁位移至少低80%。最后，在AAA部位出现裂隙（N = 5）或破裂（N = 3）的小鼠中，在整个心动周期中观察到更高的从管腔向外的位移且没有可辨别的波形（r² < 0.20）。这些发现表明，PWI可用于区分正常小鼠主动脉与动脉瘤性、裂隙性和破裂性主动脉。因此，PWI通过提供补充标准B型超声的信息，有可能用于监测和分期人类动脉瘤。
