Download Aortic Valve Premise. The aortic leaflets has a semicircular hinge

Aortic Valve
Premise. The aortic leaflets has a semicircular hinge line (where they are attached to the aortic
wall), a body (the “floor” of the leaflet) and a coapting surface (where the adjacent leaflets coapt
each other). Often aortic leaflets cannot be visualized in their entirety whit 3D RT TEE. Like tricuspid
valve, normal aortic leaflets are thin and the efficacy of machine settings (gain, compression and
smooting) in differentiating thin tissue leaflets from noises is reduced. Moreover in closing position
bodies of leaflets are almost parallel to the ultrasound beams thus echoes are weak (being mostly
scattering rather than specular echoes). As a results, when the gain is adjusted to remove noises,
quite often also these echoes disappear as well, leaving the so called “dropout artifacts”. The
dropout artifacts are less evident in systole because leaflets in opening position become nearly
perpendicular to the beams. Nevertheless, for unexplainable reasons, in some patients, the aortic
leaflets are well imaged both in diastole than in systole. We use these patients for describing the
normal features of aortic valve and aortic root.
Aortic root. The aortic root comprises the aortic valve leaflets and their hingelines, the sinuses, the
interleaflets triangles the ventriculo-arterial junction and the sinutubular junction. Most of these
structure can be imaged easily by 3D RT TEE. The aortic annulus (i.e. the hingelines of the aortic
leaflets) has a crown-shaped appearance. Unlike 2D echocardiography, 3D RT TEE can image all of
these features in one image by cropping the aortic root longitudinally (Fig 1.22).
Fig. 1.22 By cropping the aortic root longitudinally, the ventriculo-aortic junction, interleaflets triangle,leaflets, sinuses and
sinutubular junction can be imaged in a single image. This is due to the perception of space in z-axis direction given by different
shades of color.
The normal aortic valve has three semilunar leaflets. The leaflets seldom are perfectly equal in size.
Each leaflet has a semicircular hingeline, a body, and a coapting surface. The three leaflets meet
centrally along zones of apposition where adjacent leaflets coapt (Fig 1.23).
Fig.
Fig. 1.23 3D RT TEE (a) and the corresponding anatomic specimen* (b) showing the three leaflets in closing position. The three
leaflets meet centrally. * by courtesy of dr. Edgardo Bonacina
The commissures are the highest points of valvular closure lines. They reach to the level of the
sinutubular junction whereas the lower points, nadirs, cross into ventricular tissue (Fig 1.24, 1.25).
Fig. 1.24 3D RT TEE (a) and the corresponding anatomic specimen* By cropping the aortic root longitudinally, commissures can
be visualized. The hingeline of collagenous tissue where leaflets are anchored has a crown-shaped configuration.
* by courtesy of dr. Edgardo Bonacina
Fig 1.25 3D RT TEE showing the coaptation zone between the right coronary and non coronary leaflets (arrow). The asterisks
indicate the three commissures.
The electronic dissection of the volumetric data set provides some unique details of the aortic
sinuses. In Fig 1.26 the left aortic sinus is imaged with the corresponding leaflet. Note the orifice of
the left main artery is located in the upper part of the sinus (arrow)
Fig 1.26 3D RT TEE showing the left coronary sinus (LC) and the ostium of the left main coronary artery (arrow). This electronic
“piece” of heart can be obtained by properly cropping the surrounding structures. The shape of the sinus and the leaflet
together resemble the swallow’s nest.
Because of the semilunar attachment of the aortic leaflets, there are three interleaflet triangles
which are extensions of the left ventricular outflow tract since they are located beneath the level of
the leaflets when the valve is in closed position (Fig 1.27). 3D RT TEE might have difficulty in clearly
imaging the interleaflets triangle because the resolution does not allow a good definition of these
thin areas to differentiate from adjacent structures. In the figure 1.34 the arrows point the position
of the interleaflets triangles in between the sinuses but distinct features cannot be recognized.
Fig
The figures 1.28,1.29,1.30, show each of the interleaflet triangles imaged from different
perspectives. While the position of interleaflets triangle between the left and non coronary aortic
sinuses can be recognized since it forms part of the aortic-mitral curtain and in some patient (as in
the figure) the triangle appears in between the sinuses, the other triangles are featureless and their
position can be recognized only because the surrounding structures are recognizable.
Fig. 1.28 3D RT TEE showing the position of the interleaflet triangle(arrow) between the left (LC) and non-coronary sinus (NC).
This triangle forms part of the mitral-aortic curtain. This is probably the triangle that can be easier recognized more easily
because it is an extension of the anterior mitral leaflets (AML). In this case the resolution power in z-axis of the system is able to
depict the triangle by using a slight difference in color shades. RC = right coronary sinus.
Fig 1.29 3D RT TEE showing the position of the interleaflet triangle(arrow) between the right (RC) and non-coronary sinuses
(NC). The figure has been obtained by cropping the lateral wall of the right ventricle. This triangle adjoins the membranous part
of the ventricular septum. The z-axis resolution of the system is not sufficient to image the slight external bulge of the sinuses
and the triangle in between. LC = left coronary sinus
Fig 1.30 3D RT TEE showing the position of the interleaflet triangle(arrow) between the right (RC) and left coronary sinuses (LC).
The figure has been obtained by cropping the anterior wall of the right ventricle. This triangle is the only one adjoining muscular
tissue. As in the previous image the resolution power in z-axis is not sufficient to image the slight depression in between the
two coronary aortic sinuses. NC = non-coronary sinu