CARDIAC MRI
PREPARATION
- ECG, Film/Images with Reports
- Blood for Serum Creatinine (Contrast)
- Old Documents
- Operation Note (Post Oparation)
Indications for cardiac MRI
For the assessment of heart
failure
- Determination of etiology - ischemic vs. non-ischemic
cardiomyopathy
- Assessment of right and left ventricular function and
size with precise quantification
For the evaluation of ischaemic heart disease
- Viability
assessment prior to treatment (e.g. revascularisation)
- Assessment of location and extent of infarct
For the
assessment of cardiac masses- For the characterisation, extent and invasion masses
- For the assessment of pericardial disease
- Constrictive pericarditis
- Pericardial effusion
For the assessment of cardiomyopathies
- Hypertrophic
cardiomyopathy
- Dilated cardiomyopathy
- Arrhythmogenic right
ventricular cardiomyopathy
- Eosinophilic cardiomyopathy
- Restrictive
cardiomyopathies
- Myocarditis
For the assessment of valvular disease
- Detection, quantification, serial effect on ventircular function
- Valve
masses For the assessment of congenital heart disease
- Diagnosis and
treatment monitoring
- Cardiac and great vessel morphology
- Coronary
artery origin evaluation for anomalies
- Intracardiac shunts with shunt
fraction quantification
For the assessment of aorta and great vessels diseases
- Aortic aneurysm
- Aortic dissection
- Intramural haematoma
For the
assessment of myocardial infarction complications
- Aneurysms
- Thrombus
formation
For the assessment of ventricular function
For the assessment of
atrial arrhythmias
For anomalous coronary arteries
Clinical research
Indications for cardiac MRI
For the assessment of heart failure
- Determination of etiology - ischemic vs. non-ischemic cardiomyopathy
- Assessment of right and left ventricular function and size with precise quantification
For the evaluation of ischaemic heart disease
- Viability assessment prior to treatment (e.g. revascularisation)
- Assessment of location and extent of infarct
- For the characterisation, extent and invasion masses
- For the assessment of pericardial disease
- Constrictive pericarditis
- Pericardial effusion
For the assessment of cardiomyopathies
- Hypertrophic cardiomyopathy
- Dilated cardiomyopathy
- Arrhythmogenic right ventricular cardiomyopathy
- Eosinophilic cardiomyopathy
- Restrictive cardiomyopathies
- Myocarditis
For the assessment of valvular disease
- Detection, quantification, serial effect on ventircular function
- Valve masses For the assessment of congenital heart disease
- Diagnosis and treatment monitoring
- Cardiac and great vessel morphology
- Coronary artery origin evaluation for anomalies
- Intracardiac shunts with shunt fraction quantification
For the assessment of aorta and great vessels diseases
- Aortic aneurysm
- Aortic dissection
- Intramural haematoma
For the assessment of myocardial infarction complications
- Aneurysms
- Thrombus formation
For the assessment of ventricular function
For the assessment of atrial arrhythmias
For anomalous coronary arteries
Clinical research
PROTOCOL
- SURVEY_tra...20
- SURVEY_cor...20
- SURVEY_sag...20
- csBTFE_MS_SS_tra...600
- sBTFE_BH_SAG...31
- csBTFE_BH_4C...31
- csBTFE_BH_SAX....31
- csBTFE_BH_4C...31
- csBTFE_BH_4C...217
- csBTFE_BH_SAX...341
- csBTFE_BH_SAG...31
- csBTFE_BH_SAG...31
- csBTFE_BH_AX...31
- csBTFE_BH_AX...31
- csBTFE_BH_SAG...31
- T2_STIR_BB_4C...1
- T2_STIR_BB_SAX...1
- DYN_sTFE_3sl_SAX....180
- DYN_sTFE_3sl_SAX....180
- csQFLOW_BH_3C....40
- csQFLOW_BH_3C....40
- csQFLOW_BH_3C....40
- IR_TFE_LL_2beats_sax.....25
- Delayed ENHANCE_SAX....10
- Delayed ENHANCE_tra....05
- 3D_PSIR_TFE_NAV_SAX....24
- 3D_PSIR_TFE_NAV_SAX....24
- 3D_PSIR_TFE_NAV_SAX....24
- 3D_PSIR_TFE_NAV_4CH....24
- 3D_PSIR_TFE_NAV_4CH....24
- 3D_PSIR_TFE_NAV_4CH....24
- cs3D_TFE_WH_tra....140
- 3D_CINE_PCA ANGIO_COR.....550
- 3D_CINE_PCA ANGIO_COR.....550
- DYNAMIC....7
- PRALLEL....9
- COR_75/1
- CINE...7
- LR40/FHAP-80_COR......585
- LR40/FHAP-80_COR......70
PLANNING
Picture: Cardiac MRI LVOT
The great vessels of the heart function to carry blood to and from the heart as it pumps, located largely within the middle mediastinum.
In this article we will consider the structure and anatomical relationships of the aorta, pulmonary arteries and veins, and the superior and inferior vena cavae.
Aorta
The aorta is the largest artery in the body. It carries oxygenated blood (pumped by the left side of the heart) to the rest of the body.
The aorta arises from the aortic orifice at the base of the left ventricle, with inflow via the aortic valve. Its first segment is known as the ascending aorta, which lies within the pericardium (covered by the visceral layer). From it branch the coronary arteries. The second continuous segment is the arch of the aorta, from which branch the major arteries to the head, neck and upper limbs. These are:
Brachiocephalic trunk
Left common carotid artery
Left subclavian artery
After the arch of the aorta, the aorta then becomes the descending aorta which continues down through the diaphragm into the abdomen.
Fig 1 – The arch of aorta.
Clinical Relevance - Disorders of the Aorta
Aortic Dissection
Fig 1.1 – Aortic dissection, where blood enters the wall of the aorta.
Aortic dissection refers to a tear in the inner wall of the aorta. The tear creates two channels for blood flow; one is the normal lumen of the aorta, another is into the wall, where the blood becomes stationary.
Blood entering the wall can constrict the aortic lumen, reducing blood flow to the rest of the body. It can also cause further weakness and dilation of the wall, potentially leading to an aortic aneurysm.
Aortic Aneurysm
An aneurysm is a dilation (expansion) of an artery, which is greater than 50% of the normal diameter. An aortic aneurysm is due to an underlying weakness of the walls (such as Marfan’s syndrome), or a pathological process (such as aortic dissection).
The main concern with an aortic aneurysm is rupture of the aorta, which if not treated, will lead to death.
Pulmonary Arteries
The pulmonary arteries receive deoxygenated blood from the right ventricle and deliver it to the lungs for gas exchange to take place.
The arteries begin as the pulmonary trunk, a thick and short vessel, which is separated from the right ventricle by the pulmonary valve. The trunk is located anteriorly and medially to the right atrium, sharing a common layer of pericardium with the ascending aorta. It continues upwards, overlapping the root of the aorta and passing posteriorly.
At around the level of T5-T6, the pulmonary trunk splits into the right and left pulmonary arteries. The left pulmonary artery supplies blood to the left lung, bifurcating into two branches to supply each lobe of the lung. The right pulmonary artery is the thicker and longer artery of the two, supplying blood to the right lung. It also further divides into two branches.
Fig 1.2 – Anterior view of the heart, and its great vessels.
Pulmonary Veins
The pulmonary veins receive oxygenated blood from the lungs, delivering it to the left side of the heart to be pumped back around the body.
There are four pulmonary veins, with one superior and one inferior for each of the lungs. They enter the pericardium to drain into the superior left atrium, on the posterior surface. The oblique pericardial sinus can be found within the pericardium, between the left and right veins.
The superior pulmonary veins return blood from the upper lobes of the lung, with the inferior veins returning blood from the lower lobes. The inferior left pulmonary vein is found at the hilum of the lung, while the right inferior pulmonary vein runs posteriorly to the superior vena cava and the right atrium.
Superior Vena Cava
The superior vena cava receives deoxygenated blood from the upper body (superior to the diaphragm, excluding the lungs and heart), delivering it to the right atrium.
It is formed by merging of the brachiocephalic veins, travelling inferiorly through the thoracic region until draining into the superior portion of the right atrium at the level of the 3rd rib.
As the superior vena cava makes its descent it is located in the right side of the superior mediastinum, before entering the middle mediastinum to lie beside the ascending aorta.
Inferior Vena Cava
The inferior vena cava receives deoxygenated blood from the lower body (all structures inferior to the diaphragm), delivering it back to the heart.
It is initially formed in the pelvis by the common iliac veins joining together. It travels through the abdomen, collecting blood from the hepatic, lumbar, gonadal, renal and phrenic veins. The inferior vena cava then passes through the diaphragm, entering the pericardium at the level of T8. It drains into the inferior portion of the right atrium.
Anatomy The Chambers of the Heart
The heart consists of four chambers: the two atria
and the two ventricles.
Blood returning to the heart enters the
atria, and is then pumped into the ventricles. From the left ventricle,
blood passes into the aorta and enters the systemic circulation. From the
right, it enters the pulmonary circulation via the pulmonary
arteries.
In this article we shall look at the anatomy of the atria
and the ventricles, and we will consider their clinical correlations.
Atria
Right Atrium
The right atrium receives deoxygenated blood from
the superior and inferior vena cavae, and from the coronary veins. It
pumps this blood through the right atrioventricular orifice (guarded
by the tricuspid valve) into the right ventricle.
In the anatomical position, the right atrium forms
the right border of the heart. Extending from the antero-medial
portion of the chamber is the right auricle (right atrial appendage)
– a muscular pouch that acts to increase the capacity of the atrium.
The interior surface of the right atrium can be divided
into two parts, each with a distinct embryological origin. These two parts are
separated by a muscular ridge called the crista terminalis:
Sinus venarum – located posterior to
the crista terminalis. This part receives blood from the superior and
inferior vena cavae. It has smooth walls and is derived from the embryonic
sinus venosus.
Atrium proper – located anterior to the crista
terminalis, and includes the right auricle. It is derived from the
primitive atrium, and has rough, muscular walls formed by pectinate
muscles.
The coronary sinus receives blood from the
coronary veins. It opens into the right atrium between the inferior vena cava
orifice and the right atrioventricular orifice.
Interatrial Septum
The interatrial septum is a solid muscular wall
that separates the right and left atria.
The septal wall in the right atrium is marked by a small
oval-shaped depression called the fossa ovalis. This is the remnant
of the foramen ovale in the fetal heart, which allows right to left
shunting of blood to bypass the lungs. It closes once the newborn takes its
first breath.
Fig 1 – The right atrium and interatrial septum. The
atrium proper is only partially visible on this illustration.
Clinical Relevance: Atrial Septal Defect
An atrial septal defect is an abnormal opening in the
interatrial septum, persistent after birth. The most common site is the foramen
ovale, and this is known as a patent foramen ovale.
In the adult, left atrial pressure is usually
greater than that of the right atrium, so blood is shunted through
the opening from left to right. In large septal defects, this can cause
right ventricular overload, leading to pulmonary hypertension, right
ventricular hypertrophy and ultimately right heart failure.
Definitive treatment is closure of the defect by surgical
or transcatheter closure.
Left Atrium
The left atrium receives oxygenated blood from the
four pulmonary veins, and pumps it through the left atrioventricular
orifice (guarded by the mitral valve) into the left ventricle.
In the anatomical position, the left atrium forms
the posterior border (base) of the heart. The left auricle extends
from the superior aspect of the chamber, overlapping the root of the pulmonary
trunk.
The interior surface of the left atrium can be
divided into two parts, each with a distinct embryological origin:
Inflow portion – receives blood from the pulmonary
veins. Its internal surface is smooth and it is derived from the pulmonary
veins themselves.
Outflow portion – located anteriorly, and includes
the left auricle. It is lined by pectinate muscles, and is derived from
the embryonic atrium.
Ventricles
The left and right ventricles of the
heart receive blood from the atria and pump it into the outflow vessels;
the aorta and the pulmonary artery respectively.
Right Ventricle
The right ventricle receives deoxygenated blood from the
right atrium, and pumps it through the pulmonary orifice (guarded by the
pulmonary valve), into the pulmonary artery.
It is triangular in shape, and forms the majority of
the anterior border of the heart. The right ventricle can be divided
into an inflow and outflow portion, which are separated by a muscular ridge
known as the supraventricular crest.
Inflow Portion
The interior of the inflow part of the right ventricle is
covered by a series of irregular muscular elevations, called trabeculae
carnae. They give the ventricle a ‘sponge-like’ appearance, and can be grouped
into three main types:
Ridges – attached along their entire length on one
side to form ridges along the interior surface of the ventricle.
Bridges – attached to the ventricle at both ends,
but free in the middle. The most important example of this type is the
moderator band, which spans between the interventricular septum and the
anterior wall of the right ventricle. It has an important conductive
function, containing the right bundle branches.
Pillars (papillary muscles) – anchored by
their base to the ventricles. Their apices are attached to fibrous cords
(chordae tendineae), which are in turn attached to the three tricuspid
valve cusps. By contracting, the papillary muscles ‘pull’ on the chordae
tendineae to prevent prolapse of the valve leaflets during ventricular
systole.
Outflow Portion (Conus arteriosus)
The outflow portion (leading to the pulmonary
artery) is located in the superior aspect of the ventricle. It is derived
from the embryonic bulbus cordis. It is visibly different from the
rest of the right ventricle, with smooth walls and no trabeculae carneae.
Fig 2 – Frontal section of the heart, showing the
attachment of the papillary muscles to the tricuspid and mitral valves.
Interventricular Septum
The interventricular septum separates the two ventricles,
and is composed of a superior membranous part and an
inferior muscular part.
The muscular part forms the majority of the septum
and is the same thickness as the left ventricular wall. The membranous part
is thinner, and part of the fibrous skeleton of the heart.
Left Ventricle
The left ventricle receives oxygenated blood from the
left atrium, and pumps it through the aortic orifice (guarded by the aortic
valve) into the aorta.
In the anatomical position, the left ventricle forms the
apex of the heart, as well as the left and diaphragmatic borders. Much like the
right ventricle, it can be divided into an inflow portion and an outflow
portion.
Inflow Portion
The walls of the inflow portion of the left ventricle are
lined by trabeculae carneae, as described with the right ventricle. There
are two papillary muscles present which attach to the cusps of the mitral
valve.
Outflow Portion
The outflow part of the left ventricle is known as
the aortic vestibule. It is smooth-walled with no trabeculae carneae, and
is a derivative of the embryonic bulbus cordis.
Fig 3 – The papillary muscles and inflow portion of the
left ventricle.
Clinical Relevance: Tetralogy of Fallot
Tetralogy of Fallot is a cyanotic congenital heart
disease, comprising four abnormalities as a result of a single development
defect. The four abnormalities are:
Ventricular septal defect
Overriding aorta (this is where the aorta is positioned
directly over the VSD)
Pulmonary valve stenosis
Right ventricular hypertrophy
Stenosis of the pulmonary valve increase the
force needed to pump blood through it, resulting in right
ventricular hypertrophy. Eventually, the pressure in the right ventricle
becomes higher than that of the left – and blood then shunts from right to left
through the ventricular septal defect. The overriding aorta lies over the
ventricular septal defect, resulting in deoxygenated blood passing into
the aorta.
It is usually treated surgically in the first few months
of life or in severe cases, soon after birth.
Fig 4 – The four structural defects in Tetralogy of
Fallot.
Anatomy The valves of the heart
The valves of the heart are structures which ensure blood
flows in only one direction. They are composed of connective tissue and
endocardium (the inner layer of the heart).
There are four valves of the heart, which are divided
into two categories:
Atrioventricular valves: The tricuspid valve and mitral
(bicuspid) valve. They are located between the atria and corresponding
ventricle.
Semilunar valves: The pulmonary valve and aortic valve.
They are located between the ventricles and their corresponding artery, and
regulate the flow of blood leaving the heart.
In this article, we will look at the anatomy of these
valves – their structure, function, and their clinical correlations
Fig 1 – The four valves of the heart, visible with the
atria and great vessels removed.
Atrioventricular Valves
The atrioventricular valves are located between the atria
and the ventricles. They close during the start of ventricular contraction (systole),
producing the first heart sound. There are two AV valves:
Tricuspid valve – located between the right atrium
and the right ventricle (right atrioventricular orifice). It consists
of three cusps (anterior, septal and posterior), with the base of
each cusp anchored to a fibrous ring that surrounds the orifice.
Mitral valve – located between the left atrium
and the left ventricle (left atrioventricular orifice). It is also known
as the bicuspid valve because it has two cusps (anterior
and posterior). Like the tricuspid valve, the base of each cusp is
secured to fibrous ring that surrounds the orifice.
The mitral and tricuspid valves are supported by the
attachment of fibrous cords (chordae tendineae) to the free edges of
the valve cusps. The chordae tendineae are, in turn,
attached to papillary muscles, located on the interior surface
of the ventricles – these muscles contract during ventricular systole to
prevent prolapse of the valve leaflets into the atria.
There are five papillary muscles in total.
Three are located in the right ventricle, and support the tricuspid valve. The
remaining two are located within the left ventricle, and act on the mitral
valve.
Fig 2 – The papillary muscles and inflow portion of the
left ventricle.
Semilunar Valves
The semilunar valves are located between the
ventricles and outflow vessels. They close at the beginning of ventricular
relaxation (diastole), producing the second heart sounds. There are two
semilunar valves:
Pulmonary valve – located between the right
ventricle and the pulmonary trunk (pulmonary orifice). The valve consists
of three cusps – left, right and anterior (named by their
position in the foetus before the heart undergoes rotation).
Aortic valve – located between the left ventricle
and the ascending aorta (aortic orifice). The aortic valve consists
of three cusps – right, left and posterior.
The left and right aortic sinuses mark the origin of the
left and right coronary arteries. As blood recoils during ventricular diastole,
it fills the aortic sinuses and enters the coronary arteries to supply the
myocardium.
The pulmonary and aortic valves have a similar structure.
The sides of each valve leaflet are attached to the walls of the outflow
vessel, which is slightly dilated to form a sinus. The free superior edge
of each leaflet is thickened (the lunule), and is widest in the
midline (the nodule).
At the beginning of ventricular diastole, blood flows
back towards the heart, filling the sinuses and pushing the valve cusps
together. This closes the valve.
Fig 3 – The aortic valve cusps, aortic sinuses, and the
origin of the coronary arteries.
Clinical Relevance: Aortic Stenosis
Aortic stenosis refers to narrowing of the aortic valve,
restricting the flow of blood leaving the heart. The main three causes are:
Age-related calcification
Congenital defects
Most commonly a bicuspid aortic valve, which predisposes the valve to calcification later in life.
Rheumatic fever
The classical triad seen in severe aortic stenosis
is shortness of breath, syncope and angina. The increasing workload for the
left ventricle can also result in left ventricular hypertrophy.
Definitive treatment is surgical, and can be achieved via
valve replacement or balloon valvuloplasty.
Fig 4 – Aortic stenosis, secondary to rheumatic heart disease. The aorta has been removed to show thickened, fused aortic valve leaflets and opened coronary arteries from above.
CARDIAC MRI PICTURE
POST PROCESSING
