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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3676_Библиотеки_им_академика_М_И_Перельмана
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T.A. Hameed
Fig. 14.17 Coronal image of aorta to assess height of
ostium of LMCA (derived from Fig. 14.16)
Fig. 14.18 Sagittal image at the level of LMCA
Fig. 14.19 Coronal image showing LMCA ostium
height from the level of annulus
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Fig. 14.20 Computer
software generated curve
predicting the
appropriate fluoroscopic
tube angle
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Fig. 14.21 3D Volume rendered image of aortic root and
ascending aorta showing the annulus plane corresponding
to Fig. 14.20
Fig. 14.22 Angiogram during implantation of Sapien 3
29 mm valve via transfemoral approach
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14.2.4 Pearls and Pitfalls
Transaxial image of aortic valve annulus is easier
to acquire by first obtaining transverse view of
aortic valve leaflets at mid sinus level with the
three leaflets symmetrical in appearance, and by
making adjustments to the sagittal oblique and
coronal oblique images to find the appropriate
longitudinal axis through the valve. The transverse plane may then be moved inferiorly along
the long axis to the level of inferior hinge point of
the leaflets for annulus image.
14.3 Case 2
14.3.1 History
CT examinations performed in patients with
severe aortic stenosis for pre-TAVR evaluation.
14.3.2 Findings
Contrast enhanced CT angiography examinations
for evaluation of iliofemoral access.
Figure 14.23a–d: There is mild to moderate
tortuosity of right iliac arteries and mild tortuosity of left iliac arteries. Transaxial image of the
iliac artery demonstrates normal caliber and no
vascular calcifications.
Figure 14.24a, b: There is relatively small
caliber of the iliac artery with circumferential
calcification.
Figure 14.25a–d: There is large calcified
plaque with severe stenosis of distal aorta and
common iliac arteries.
Figure 14.26a, b: There is severe tortuosity of
aorta and iliac arteries.
Diagnosis:
CT examinations in different patients demonstrate normal and abnormal appearances for the
evaluation of risk of vascular complications for
TAVR procedure by iliofemoral route.
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a
b
c
d
Fig. 14.23 (a) Volume rendered image of aorta and iliac arteries (b) Right common iliac reference image (c) Transaxial
image of right external iliac artery (d) Right external iliac reference image
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Fig. 14.24 (a, b) Iliac artery with circumferential calcification luminal diameter of 5.66 mm
T.A. Hameed
Fig. 14.25 Axial images (a–d) and Coronal Image (e) showing large calcified plaque with severe stenosis of distal
aorta and common iliac arteries
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e
Fig. 14.25 (continued)
14.3.3 Discussion
A variety of image reformats are acquired to optimally assess the aorta and iliac arteries. These
include curved multiplanar reformats with transaxial
images using centerline reformats, MIP and 3D VR.
The size criteria for arterial caliber for safe
access vary with the type and size of the valve
and the size of its vascular access device/sheath.
With recent developments, the size of vascular
access devices has decreased. Although it is preferable to have the diameter of iliac arteries larger
than the size of access sheath, the procedure can
still be performed safely with slight vessel/sheath
size mismatch over a short distance due to distensibility of normal vessels. This distensibility is
reduced with diseased vessels with calcifications.
Circumferential or horse-shoe calcifications
increase the risk of vascular injury and rupture.
Marked tortuosity of aorta or iliac arteries can
limit catheter maneuverability for TAVR. This
becomes more important in patients with severe
atherosclerotic calcifications with decreased
vessel compliance or with vessel stenosis. In the
case presented (Fig. 14.26), the TAVR was performed via transfemoral route.
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Fig. 14.26 (a, b) Volume rendered images of aorta and iliac arteries showing severe tortuosity
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14.3.4 Pearls and Pitfalls
True transaxial images of the arteries are important in the assessment of arterial caliber, particularly in the region of vessel bifurcation or
tortuosity or in cases of arteries with relatively
small caliber. The centerline reformats through
the vessels at bifurcation or tortuosity should be
carefully scrutinized to ascertain true axial
images perpendicular to the long axis of the vessels, so as not to over- or underestimate vessel
size due to obliquity of plane.
The presence of dense arterial calcifications
can cause difficulty in the assessment of luminal
size due to similar attenuation of contrast enhanced
arteries in some cases. Selecting a wide window
width for display is useful to maximize the difference between contrast enhanced lumen and calcification in the wall particularly for vessels with
generally small caliber such as external iliac arteries. Dense calcifications may cause low density
streaks secondary to beam hardening artifacts.
14.4.2 Findings
Figure 14.27: Transaxial images at the level of
aortic valve cusps reconstructed in the systolic
phase at 30% R-R interval: There is a bicuspid
aortic valve (BAV) with fused, small right and
left coronary cusps with a single raphe corresponding to Type 1 BAV. There is heavy calcification in the cusps. Incomplete opening of the
valve during systole is consistent with severe aortic stenosis. Figure 14.28: Transaxial image at the
level of the aortic annulus demonstrates a diameter of 31 × 25.3 mm. The area was 607 mm2 with
effective diameter based on area 27.8 mm.
Figure 14.29: Intraoperative fluoroscopy/angiography images during TAVR procedure demonstrate placement of a 29 mm Medtronic
Core-valve just prior to, during, and after expansion in aortic valve. Figure 14.30: Chest X-ray
showing the implanted CoreValve.
14.4 Case 3
14.4.1 History
An 84-year-old male patient with severe aortic
stenosis diagnosed on echocardiography; being
evaluated for TAVR.
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a
b
c
Fig. 14.27 (a, b, c) Transaxial images at the level of aortic valve cusp showing bicuspid aortic valve and large amount
of calcifications
Fig. 14.28 Transaxial image at the level of the aortic
annulus
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a
b
c
Fig. 14.29 Angiogram images of TAVR: Prior to (a), during (b), and after expansion (c) of Core-valve
Fig. 14.30 Chest X-ray after the CoreValve implantation
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