Abnormal flow dynamics within the ascending aorta of the patients with aortic valve stenosis. Assessments with phase resolved three dimensional phase contrast MR image (4D-Flow).

Congress:

ECR 2013

Poster Number:

C-2504

Type:

Scientific Exhibit

Keywords:

Dilatation, Imaging sequences, Computer Applications-3D, MR-Angiography, MR, Cardiovascular system, Arteries / Aorta, Aneurysms

Authors:

M. Sugiyama¹, Y. Takehara¹, T. Saito¹, N. Ooishi¹, M. Alley², T. Wakayama³, M. Terada⁴, S. Yoshihara⁴, H. Sakahara¹; ¹Hamamatsu/JP, ²Stanford, CA/US, ³Hino/JP, ⁴Iwata/JP

DOI:

10.1594/ecr2013/C-2504

DOI-Link:

https://dx.doi.org/10.1594/ecr2013/C-2504

Fig. 3: The WSS of an AS patient (the same case as Fig.1) at systole. The WSS of the...

Fig. 7: The OSI of an AS patient (the same case as Fig.1). Higher OSI is seen on the...

Purpose

Abnormal flow dynamics associated with aortic valve stenosis (AS) is widely believed to be related to post-stenotic dilatation of the ascending aorta, or sometimes hemorrhages from the gastrointestinal angiodysplasia, which is now believed to be due to the breaking down of the coagulation factor VIII by the abnormal flow occurring around the stenosed valve(1). The purpose of the study is to characterize the flow dynamics of the ascending aorta in AS patients by phase resolved 3D phase contrast MRI (4D-FLOW).

Methods and Materials

Three AS patients diagnosed with echocardiography and cardiac catheterization were examined on 3T MR scanner. ECG gated, gradient-echo-based coronal 4D-Flow covering the whole heart and the ascending aorta was performed following the contrast enhanced MR Angiography (Gd3DMRA) performed for the determination of the aortic boundary. Age-matched five patients without AS were also examined in a same way. Written informed consent was acquired in all patients. MR imaging All examinations were performed on 3.0T MR scanner (Discovery 750, GE Healthcare, WI, USA). 2D PC cine study...

Results

The Flow Dynamics Streamline images delineated the vortex and/or helical flow within the dilated ascending aorta throughout the cardiac cycle in all AS patients. The abnormal flow appears from the base of ascending aorta throughout all cardiac cycle within all AS patients. On the other hand the flow pattern of the control patients is mostly laminar at systole with brief turbulence while diastole. This implies an important roll of the AS in the formation of abnormal flow dynamics at systole and subsequent dilatation. The Wall...

Conclusion

Streamline or pathline images delineated the vortex and/or helical flow within the dilated ascending aorta throughout the cardiac cycle in all AS patients, which were not observed in the control patients. The wall shear stress (WSS) calculated at the ascending aorta showed reduced WSS less than 0.5 Pa of the wall due to the complex abnormal flow dynamics in all three patients. The flow patterns of the control group in the ascending aorta was mostly laminar at systole with brief turbulence while diastole. 4D-FLOW method...

References

1. Loscalzo J. From clinical observation to mechanism--Heyde's syndrome. N Engl J Med. 2012 Nov 15;367(20):1954-6.