Gradient Echo MRI Characterization of Development of Atherosclerosis in the Abdominal Aorta in Watanabe Heritable Hyperlipidemic Rabbits

Journal Article · Tue Aug 15 04:00:00 EDT 2006 · Cardiovascular and Interventional Radiology

DOI:https://doi.org/10.1007/S00270-005-0073-5· OSTI ID:21091167

Kuribayashi, Hideto ^[1]; Wagberg, Maria ^[2]; Holmes, Andrew P; Tessier, Jean J; Waterton, John C ^[1]

---

1. AstraZeneca (United Kingdom)
2. AstraZeneca (Sweden)

Purpose. The Watanabe Heritable Hyperlipidemic (WHHL) rabbit provides an important model of spontaneous atherosclerosis. With a strain of WHHL rabbits which do not develop abdominal aorta lumen stenosis even with advanced atherosclerosis, we studied the MRI-histology correlation, and the natural progression of atherosclerosis in the abdominal aorta. In addition, intra-reader segmentation repeatability and scan-rescan reproducibility were assessed. Methods. Two batches of female WHHL rabbits were used. The first batch of 6 rabbits was scanned at 20 weeks old. A second batch of 17 rabbits was scanned at 50 weeks old and then randomly divided into two subgroups: 8 were killed for histologic investigation; 9 were kept alive for follow-up, with repeat scanning a week later to assess scan-rescan reproducibility, and again at 73 weeks old to assess disease progression. MR images were acquired at 4.7 T using a chemical shift selective fat suppression gradient echo with a saturation band suppressing blood signal within the aortic lumen. Five slices per animal were acquired, centered around the renal artery region of the abdominal aorta, with in-plane resolution of 0.195 mm and slice thickness of 3 mm. Results. The coefficient of variation for intra-reader reproducibility for aortic wall thickness measurements was 2.5% for repeat segmentations of the same scans on the same day, but segmentations of these same scans made 8 months later showed a systematic change, suggesting that intra-reader bias as well as increased variability could compromise assessments made over time. Comparative analyses were therefore performed in one postprocessing session. The coefficient of variation for scan-rescan reproducibility for aortic wall thickness was 5.5% for nine pairs of scans acquired a week apart and segmented on the same day. Good MRI-histology correlation was obtained. The MRI-measured mean aortic wall thickness of animals at 20 weeks of age was 76% that of animals at 50 weeks of age (p < 0.001). There was a small increase in aortic wall thickness between 50 and 73 weeks of age, but this was not significant (p > 0.05). The corresponding differences in lumen cross-sectional areas at 20, 50, and 73 weeks of age were not significant. These results were consistent with in-house historical histology data on this strain of rabbits. Conclusions. High-resolution gradient echo MRI can follow disease progression in the WHHL rabbit spontaneous atherosclerosis disease model.

• OSTI ID: 21091167
• Journal Information: Cardiovascular and Interventional Radiology, Journal Name: Cardiovascular and Interventional Radiology Journal Issue: 4 Vol. 29; ISSN 0174-1551; ISSN CAIRDG
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
AORTA
ARTERIOSCLEROSIS
BLOOD
CHEMICAL SHIFT
HISTOLOGY
IMAGES
KIDNEYS
NMR IMAGING
RABBITS
THICKNESS