Segmentation of lumen and outer wall of abdominal aortic aneurysms from 3D black-blood MRI with a registration based geodesic active contour model

Abstract

Segmentation of the geometric morphology of abdominal aortic aneurysm is important for interventional planning. However, the segmentation of both the lumen and the outer wall of aneurysm in magnetic resonance (MR) image remains challenging. This study proposes a registration based segmentation methodology for efficiently segmenting MR images of abdominal aortic aneurysms. The proposed methodology first registers the contrast enhanced MR angiography (CE-MRA) and black-blood MR images, and then uses the Hough transform and geometric active contours to extract the vessel lumen by delineating the inner vessel wall directly from the CE-MRA. The proposed registration based geometric active contour is applied to black-blood MR images to generate the outer wall contour. The inner and outer vessel wall are then fused presenting the complete vessel lumen and wall segmentation. The results obtained from 19 cases showed that the proposed registration based geometric active contour model was efficient and comparable to manual segmentation and provided a high segmentation accuracy with an average Dice value reaching 89.79%.

Evaluation of the distribution and progression of intraluminal thrombus in abdominal aortic aneurysms using high‐resolution MRI

“…Second, no gross or histologic validation of ILT macrostructure and biochemical composition was performed in this cohort; such validation could strengthen our hypotheses regarding the etiology of signal changes, and shed light on the underlying biochemomechanics that govern the complex and related evolution of aortic aneurysms and intraluminal thrombus. Third, although we provided both qualitative and quantitative descriptions of ILT signal and thrombus burden, future work including quantification of 3D morphology and texture could improve the characterization of ILT from the rich 3D datasets . Future work may also incorporate more advanced imaging methods including MRI and PET/CT markers of inflammation, providing a more comprehensive evaluation of both ILT and the underlying vessel wall .…”

“…Third, although we provided both qualitative and quantitative descriptions of ILT signal and thrombus burden, future work including quantification of 3D morphology and texture could improve the characterization of ILT from the rich 3D datasets. 12,24 Future work may also incorporate more advanced imaging methods including MRI and PET/CT markers of inflammation, providing a more comprehensive evaluation of both ILT and the underlying vessel wall. [25][26][27][28] Additionally, different ILT signal intensity may correlate with different mechanical characteristics, 9,29 which could better inform computational modeling of AAA mechanics.…”

“…The lumen and outer wall boundaries of AAA were automatically segmented using a previously developed level‐set method (Fig. a) . Another experienced reviewer checked the segmentation results and manually corrected the contours when the automatic segmentation method had errors.…”

“…2a). 12 Another experienced reviewer checked the segmentation results and manually corrected the contours when the automatic segmentation method had errors. The volume of ILT and of the entire AAA were recorded.…”

Fully automatic segmentation of 4D MRI for cardiac functional measurements

“…It is therefore more difficult to delineate the epicardial contour with the same methods that work for segmenting endocardial contours. Similar to our previous work on segmenting the outer wall of the abdominal aortic aneurysms 41 , we here propose to replace the signal intensities of the voxels within the LV chamber with the mean value of a one-voxel-thick layer outside the LV chamber. This yields a more efficient and reliable delineation of the epicardial border using LSSPM and the dilated LV chamber as an initial contour.…”