Results

1
Characterisation of Abdominal Aortic
Aneurysm E.A. van Dam, J. Brands, M.C.M. Rutten,
F.N. van de Vosse Biomechanics Biomechanics and
Tissue Engineering, Cardiovascular Biomechanics

• Results
• Figure 2 shows the MRI and histological
  results. It can clearly be seen that different MR
  contrast methods show different structures.
• Figure 2. T1w(a), pT2w(b), FFE-MT(c), PDw(d),
  T2w(e) and the stained section (f) where yellow
  is collagen, red is fibrin or muscle, blue is
  mucine and black is elastin.
• Discussion

Introduction Surgical treatment of abdominal
aortic aneurysm (AAA) has a mortality rate of 4
. Therefore the decision to operate has to be
made carefully. The currently used decision
method based on AAA diameter has been shown not
to be reliable. A better method might be to study
wall stresses 1, which can be provided by a
patient specific model of the aneurysm. Such a
model requires knowledge of the composition of
the AAA vessel wall which is preferably acquired
non-invasively. Multi-contrast MRI has been shown
to be a successful method to classify calcium,
fibrous tissue and lipid rich tissue in the
carotid vessel walls by combining T1, T2 and
proton density (PD) weighted images 2. In
this research the ability of multi-contrast MRI
to determine the composition of the AAA vessel
wall is studied. Figure 1 Abdominal
Aortic Aneurysm (a) and tissue used for histology
and MRI (b) The original position of the tissue
is roughly indicated in (a). Material and
methods To determine the composition of AAA
tissue hhistological samples and multi-contrast
MR images of the same specimen were used. This
AAA tissue was obtained from patients treated
with conventional repair surgery. The tissue was
cut into two parts, one section was used for
multi-contrast MRI imaging, the other section was
stained for this examination using Movats
pentachrome. The tissue was imaged on a 1.5T
scanner(Philips) with a surface coil. Specimens
were stored in formalin and immersed in fomblin,
which has no MR signal, which ensured high
contrast between tissue and surroundings. Five
different MR contrasts were obtained T1w turbo
spin echo (TSE), proton density weighted (PDw)
TSE, partial T2TSE, T2w TSE and fast field echo
with magnetization transfer (FFE-MT). Pixel size
in all images is 0.4x0.4mm.