Cardiac Anatomy Using CT

Published on 13/02/2015 by admin

Filed under Cardiothoracic Surgery

Last modified 22/04/2025

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Cardiac Anatomy Using CT

Cardiac CT Axial 1

Technical Consideration

Typically, cardiac CT axial examinations are specifically tailored to image the heart, and therefore the imaging volume is restricted to only a portion of the thorax. Often the examination begins just below the carina, as this first plate shows. Note how the contrast bolus shows bright enhancement of the left-sided cardiovascular structures—the aorta and pulmonary veins—whereas right-sided structures (pulmonary arteries) are poorly enhanced. This is purposely accomplished by following the intravenous contrast bolus with a saline injection to “wash out” dense intravenous contrast from the right heart and thereby improve visualization of the right coronary artery.

Cardiac CT Axial 2

Normal Anatomy

Several millimeters inferior to Axial 1 again shows intense enhancement of left-sided cardiovascular structures—the ascending and descending thoracic aorta and pulmonary veins. A small amount of normal pericardial fluid is seen within the left pulmonic recess of the transverse sinus of the pericardium. The origin of the right middle lobe pulmonary artery is visible, marking the distal aspect of the right interlobar pulmonary artery and the beginning of the right lower lobe pulmonary artery.

Cardiac CT Axial 3

Normal Variant

The medial segment of the right middle lobe and lingular arteries are visible at this level. Usually the right middle lobe pulmonary artery arises from the distal right interlobar pulmonary artery and branches into medial and lateral segments. However, in this patient, the medial and lateral segments of the right middle lobe pulmonary artery arise directly from the right interlobar pulmonary artery.

Normal Anatomy

The pericardial space is divided into the pericardium proper, consisting of a postcaval recess and right and left pulmonary vein recesses, and the transverse and oblique sinuses. The transverse sinus lies posterior to the ascending aorta and main pulmonary artery and cranial to the left atrium. The transverse sinus is further subdivided into superior and inferior aortic recesses and right and left pulmonic recesses. The oblique sinus also contains the posterior pericardial recess. Small amounts of fluid are commonly seen within some of these compartments in normal patients during thoracic and cardiovascular CT examinations.

Cardiac CT Axial 4

Normal Anatomy

Along the anterior aspect of the ascending aorta and main pulmonary artery, the normal pericardium is visible. A small amount of fluid immediately subjacent to the pericardium in this region, interposed between the ascending aorta and main pulmonary artery (∗), is within the anterior portion of the superior recess of the transverse sinus.

Cardiac CT Axial 5

Cardiac CT Axial 6

Cardiac CT Axial 7

Cardiac CT Axial 8

Cardiac CT Axial 9

Normal Anatomy

The crista terminalis is now just visible and will be readily visualized on views that follow. The crista terminalis is a vertical fibromuscular ridge that separates the smooth portion of the right atrium, which receives the superior and inferior vena cavae and coronary sinus, from the right atrial appendage and the remainder of the right atrium containing pectinate muscles. The crista terminalis extends superiorly from the anterior margin of the superior vena cava along the lateral wall of the right atrium inferiorly toward the inferior vena cava. A prominent crista terminalis can occasionally be mistaken for a right atrial mass on imaging studies.

Cardiac CT Axial 10

Cardiac CT Axial 11

Normal Anatomy

This image shows the origin of the first septal perforator branch of the proximal left anterior descending coronary artery (also known as the anterior interventricular branch of the left coronary artery). The first septal perforator coronary artery provides blood flow to the interventricular septum and conduction system of the heart. Disruption of blood flow within the proximal segment of the left anterior descending artery and first septal perforator vessel, as may occur with significant atherosclerosis in the left main or proximal left anterior descending coronary arteries, may result in cardiac dysrhythmias and a large myocardial infarction, leading to sudden cardiac death.

Cardiac CT Axial 12

Cardiac CT Axial 13

Cardiac CT Axial 14

Cardiac CT Axial 15

Normal Anatomy

A linear low-attenuation structure extending anteriorly from the crista terminalis is visible; this structure represents the septum spurium. The septum spurium is the most prominent of the anterior pectinate muscles arising from the crista terminalis.

Cardiac CT Axial 16

Cardiac CT Axial 17

Cardiac CT Axial 18

Cardiac CT Axial 19

Normal Anatomy

The sinoatrial nodal coronary artery is visible. The sinoatrial node is the source of the cardiac impulse and is typically located at the junction of the superior vena cava and right atrium, in the superior end of the crista terminalis. The sinoatrial nodal artery usually arises as a single branch from the right coronary artery, as in this patient (see Axials 20 to 25), or, less commonly, the sinoatrial nodal artery may arise from the left circumflex coronary artery. The sinoatrial nodal artery may be followed superiorly toward the location of the sinoatrial node.

Cardiac CT Axial 20

Cardiac CT Axial 21

Cardiac CT Axial 22

Cardiac CT Axial 23

Cardiac CT Axial 24

Cardiac CT Axial 25

Cardiac CT Axial 26

Cardiac CT Axial 27

Cardiac CT Axial 28

Normal Anatomy

The left ventricular outflow tract is shown, demonstrating that the inflow (mitral valve) and outflow tracts of the left ventricle are closely related to one another. This contrasts with the right ventricle, in which the inflow portions (tricuspid valve) and outflow portions (right ventricular outflow tract, infundibulum, and pulmonic valve) are widely separated. Note that the left ventricular outflow tract is smooth, and that the anterior leaflet of the mitral valve is closely related to the aortic valvular apparatus (see Axials 22 to 25).

Cardiac CT Axial 29

Cardiac CT Axial 30

Cardiac CT Axial 31

Cardiac CT Axial 32

Cardiac CT Axial 33

Technical Consideration

The mitral valve (left atrioventricular valve) is clearly open, indicating that this image was acquired during diastole. As discussed above in the Introduction, at lower heart rates, cardiac CT axial examinations are performed during diastole, when cardiac motion is minimal—this allows for nearly motion-free images.

Cardiac CT Axial 34

Cardiac CT Axial 35

Cardiac CT Axial 36

Cardiac CT Axial 37

Cardiac CT Axial 38

Normal Anatomy

This view, and views located both cranial and caudal to this level, shows an irregular surface of the left ventricle, representing trabeculae carneae. Most of the left ventricle is covered by a mesh of trabeculae carneae, sparing only the left ventricular outflow tract (aortic vestibule). Trabeculae carneae are also present within the right ventricle but cannot be seen on this examination because the iodinated contrast has been “washed” from the right cardiac chambers by the use of a saline injection following the intravenous contrast injection (see Introduction above). See the section detailing cardiac MR anatomy for demonstration of right ventricular chamber anatomy.

Cardiac CT Axial 39

Cardiac CT Axial 40

Cardiac CT Axial 41

Cardiac CT Axial 42

Cardiac CT Axial 43

Cardiac CT Axial 44

Cardiac CT Axial 45

Cardiac CT Axial 46

Normal Anatomy

The atrioventricular nodal coronary artery arising from the right coronary artery is shown. The atrioventricular nodal coronary artery arises from the right coronary artery in 90% of patients.

Cardiac CT Axial 47

Cardiac CT Axial 48

Cardiac CT Axial 49

Cardiac CT Axial 50

Normal Anatomy

Coronary arterial dominance is variably defined by the vessel that gives rise to the posterior descending coronary artery (also known as the posterior interventricular coronary artery) or the atrioventricular nodal coronary artery. In approximately 85% of individuals, the right coronary artery is dominant, as is the case for this patient.

Cardiac CT Axial 51

Cardiac CT Axial 52

Cardiac CT Axial 53

Cardiac CT Axial 54

Cardiac CT Axial 55

Cardiac CT Axial 56

Cardiac CT Axial 57

Cardiac CT Axial 58

Cardiac CT Axial 59

Cardiac CT Axial 60

Cardiac CT Axial 61

Cardiac CT Axial 62

Cardiac CT 2-Chamber 1

Technical Consideration

Cardiac imaging is often interpreted with images displayed in planes oriented with reference to the cardiac axis, as opposed to the axes of the body as is typical for most imaging applications (the axial, coronal, and sagittal planes). Cardiac imaging planes typically include “two-chamber,” “three-chamber,” “four-chamber,” and “short axis” planes, and are commonly used for cardiac CT, MRI, nuclear medicine, and echocardiography. This “two-chamber” or “vertical long axis” view of the heart is useful for assessing the left ventricular cavity, left ventricular inferior and anterior wall motion, the mitral valve, and the left atrial appendage.

Cardiac CT 3-Chamber 1

Technical Consideration

This “three-chamber” view of the heart is useful for displaying the left ventricular outflow tract, left atrium, and mitral and aortic valves. The anteroseptal and inferolateral walls of the left ventricle are also well demonstrated. Note how the continuity between the aortic valve apparatus and anterior mitral valve are well shown in this view.

Cardiac CT 4-Chamber 1

Technical Consideration

This “four-chamber” or “horizontal long axis” view is oriented through the mid portions of the right and left ventricles, along a plane extending through the mitral valve to the apex of the heart. This projection provides a more precise analysis of ventricular size and morphology than standard axial, coronal, or sagittal imaging and is useful for assessing the function of the mitral and tricuspid valves. Left ventricular septal and lateral wall motion is also evaluable in this view.

Cardiac CT Short Axis 1

Technical Consideration

This “short axis” view is oriented orthogonal to the four-chamber view, perpendicular to the long axis of the left ventricle from the mitral valve to the apex of the heart. This view is used for calculation of ventricular volumes and ejection fraction as well as assessment of left ventricular wall motion.

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Netters Correlative Imaging Cardiothoracic Anatomy