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-=Parasternal Long Axis=
+=Parasternal Short Axis=
-[[Image:echo_heart_parasternal_long_axis.jpg|thumb|Image showing the left parasternal long axis transection (PSLAX) of the heart by the ultrasound waves]]
+==Purposes of Getting a Good Parasternal Short Axis View==
-==Purposes of Getting a Good Parasternal Long Axis (PLAX) View==
+The parasternal short axis view is the cross-sectional view of the heart. It analyzes the different sections of the heart from the base to the apex. This view is useful in helping with the diagnosis of mitral stenosis and congenital heart disease, among others.
-Echocardiographic examination of the heart usually begins with a PLAX view. Acquiring a good PLAX view is important to assess left ventricular contractility and to determine the presence of pericardial effusion and right ventricular strain.
+==How to Get a Good Parasternal Short Axis View==
-==How to Get a Good PLAX View==
+[[Image:Heart_normal_short_axis_echo.png|thumb|Image showing the left parasternal short axis transection (SAX) of the heart and the different structures]]
-To get a good PLAX view, begin with placing the transducer in the third or fourth intercostal space and adjust as necessary, moving a few intercostals spaces up or down. Better results are obtained if the patient is placed in a left lateral decubitus position. This will allow better visualization of the mid-portion and base of the left ventricle, both leaflets of the mitral valve, the aortic valve and the aortic root, the left atrium and the right ventricle. <cite>Nihoyannopoulos</cite>
+As with the parasternal long axis, the probe placement in locating the parasternal short axis is still the same, but the rotation and orientation of the beam differ.
-The transducer is traditionally moved and pointed toward the right shoulder to parallel the beam to the major axis of the left ventricle and to pass it through the center of the left ventricular chamber. Gradual medial to lateral angulation until the left ventricle size is at its maximum will allow one to see the minor axis at its maximal state and the mitral valve leaflet excursion at its greatest. Minor axis dimensions may then be viewed and recorded.
+This view is usually taken right after the parasternal long axis view. So with the probe already at the left side of the sternum,  to get a good parasternal short axis view, start with rotating the transducer 90° clockwise. The probe has tendency to slide so apply light pressure while manipulating it. For a better view, the patient may be placed in a left lateral decubitus position or the probe may be moved to higher intercostal spaces.
-==Characteristics of a Good PLAX View==
+==Levels of Imaging in PSS==
-One will be able to know of a good PLAX view is taken when the septum is oriented almost horizontally, clearly delineating between the left and right side of the heart, and the apex of the of the left ventricle and the tricuspid valve are not visualized. The mitral and aortic valves, however, should be visible.
+[[Image:Heart_aortic_short_axis_section.jpg|thumb|right|Heart aortic short axis]]
-==Structures that can be seen in the PLAX view==
+Theoretically, there are numerous short axes between the apex and base of the heart. But the parasternal short axis view (SAX) is usually made on three levels: mitral valve level, midpapillary level, and aortic level.
-[[Image:Heart_normal_lpla_echo_view.png|thumb|Schematic diagram of the different structures seen in a good PLAX view.]]
+===Mitral Valve Level===
-*Right ventricle
+The tip of the anterior mitral valve leaflet is the most useful starting point in starting this level of inspection of the parasternal short axis view. This level shows the cross section of the left ventricle defined by the thick muscular walls of the interventricular septum and the lateral free wall. Proper recording in this level allows assessment of the wall motion of the mid-left ventricle and mitral leaflet excursion as well as visualization of a part of the right ventricle. Any abnormalities in the curvature of the interventricular  septum, and its motion, shape, or position may be detected.
-*Left ventricle
+A common feature of this level is the so-called “goldfish mouth” look of the mitral valve leaflets. Subtly weeping the beam of the probe from the base to the apex will provide the opportunity to assess the mitral valve orifices, mitral valve chordae and their insertion in the papillary muscles, and coaptation of the leaflets.
-*Mitral valve
+The use of color Doppler while in the mitral level is useful in the diagnosis of mitral valve regurgitation and its origin and, with M-mode, its timing as well.
-*Left atrium
+{{IncludeFlash
-*Descending aorta
+|flash_string=<flash>file=Test13.swf|quality=best|align=center|width=300|height=200</flash>
-*Aortic valve
+|file_name=Test13
-*Aortic root
+|Description=Echocardiographic parasternal short axis. Note the typical shape of the mitral valve
-*Pericardium
+}}
-*Right ventricular inflow and outflow tracts
 {{clr}}
-==2D Echo Measurements==
+===Midpapillary Level===
-Majority of measurements are done with 2D echo imaging. Once the best diastolic frame having the largest left ventricular cavity is chosen, septal and posterior wall thickness, left ventricular diastolic cavity, and aortic root diameter can be determined. Use a systolic frame to measure the dimensions of the left ventricle and the left atrial diameter.
+Tilting the probe toward the apex scans the midpapillary plane of the parasternal short axis. This level in the parasternal short axis view shows the left ventricle clearly between the two papillary muscle groups. The left ventricle is bordered by lateral free wall on its right, the muscular interventricular  septum on its left, and the inferior free wall at the bottom. The right ventricle is easily visualized and differentiated from the left because it has only one prominent papillary muscle.
+This view is ideally used for ventricular wall motion segmental analysis. Thickening and wall motion is visualized in ten segments of the mitral valve and papillary muscle levels.
-==M-Mode Echo Measurement==
+{{IncludeFlash
-[[Image:PLAX_Mmode.jpg|thumb|alt=Alt text|Image showing the left parasternal long axis transection (PSLAX) of the heart by M-mode imaging.]]
+|flash_string=<flash>file=SAXPAP_normal.swf|quality=best|align=center|width=300|height=200</flash>
-Determining left ventricular dimensions and ejection fraction are few of the cases wherein M-mode imaging is used. It is one-dimensional and usually relies on the correct alignment of the M-mode along the left ventricle.
+|Description=A parasternal short axis on midpapillary level
+|file_name=SAXPAP_normal
-==Using Color Doppler Ultrasound==
+}}
-It is sometimes necessary to use color Doppler ultrasound when valvular regurgitation is suspected, although this method should not be used to as the final diagnostic tool to determine valve dysfunction as the Doppler beam is nearly perpendicular to the flow. Instead, the presence of valvular regurgitation is based on the cardiac cycle, not the color-coding.<cite>Feigenbaum1</cite>
+{{clr}}
+===Aortic Level===
+The base of the heart or the aortic level of the parasternal long axis view can be visualized by tilting the transducer toward the patient’s right shoulder and by rotating it slightly clockwise. The aortic valve is between the left atrium (anterior) and the right ventricle (posterior). The aortic valve and its three leaflets are part of the so-called Y-shape configuration composed of the coronary in the upper region, right coronary in the lower left, and non coronary in the left. The following conditions can be assessed using the aortic level of the parasternal short axis view: aortic root size, structural alterations of the Valsalva sinus, proximal aortic dissection, and presence of anomalies of the aortic valve and abnormalities of the valve leaflets.
+Aside from the aortic valve, the other structures that may be observed from this level are the tricuspid valve (at the left of the aortic valve and above the posteroseptal leaflet), right ventricular outflow tract (along the aortic root), pulmonary valve (at the right and anterior to the aortic valve), and pulmonary artery and both its left and right branches (around the aorta).
+This view is often omitted and is hard to aquire.
+{{IncludeFlash
+|flash_string=<flash>file=SAXAP_normal.swf|quality=best|align=left|width=300|height=200</flash>
+|Description=A parasternal short axis on aortic level
+|file_name=SAXAP_normal
+}}
 {{clr}}
+==Sources==
-==References==
 <biblio>
-#Nihoyannopoulos isbn=1848822928
+#Zamorano isbn=1848824203
 #Feigenbaum1 isbn=0781795575
 </biblio>