2. Cardiac MRI consists of using MRI to
study heart anatomy, physiology, and
pathology.
3. Advantages
Cardiac MRI offers:
improved soft tissue definition
protocol can be tailored to likely
differential diagnoses
◦ a large number of sequences are available
◦ dynamic imaging provides functional
assessment
no ionizing radiation
◦ MRI safety still requires consideration
14. Pulse sequences-Overview
Black blood-anatomy
Spin echo(SE)
Bright blood-dynamic and angiography
Gradient echo(GE)
Phase contrast(PC)-quantify flow
Delayed enhancement-
infarct/inflammation/infiltration
2D SSFP with IR prep
Gadolinium assisted MRA
3D fast spoiled GE
15. Basic cardiovascular MR imaging
sequences include black blood imaging
and bright blood imaging.
Black blood imaging is used to depict
anatomy, pericardial and mediastinal
abnormalities, and extra luminal aortic
disease.
Black blood imaging includes ECG-gated
true spin-echo or fast spin-echo imaging
or inversion-recovery (IR) half-Fourier
single-shot turbo fast-spin-echo
sequences.
16. Bright blood imaging is used to
demonstrate flow and motion and to
image valvular disease.
Bright blood cine sequences include
segmented-k-space small-flip-angle
gradient-echo sequences or fast
imaging with steady-state precession
or refocused steady-state free
precession (SSFP)
22. Advantages
Since it uses the residual transverse
magnetization instead of wasting
it,there is increased signal to noise
ratio.
Since transverse magnetization is
added back to longitudinal
magnetization,the steady state is
reached quicker,in as little as single
TR.
The TRs are extremely
23. The images have both T1and T2
weighted.(The molecules with long T2
and short T1 will have bright
signal(both fat and water)
Thus bright signal in steady state
white blood images is attributable to
T1 and T2 signal from the blood,not
flow related.
24. Gating of white blood images allows
evaluation of dynamic cardiac function
and physiology throughout cardiac
cycle.Examples include motion of
myocardium and valve leaflets.
Gating in white blood images serve to
time image acquisition during diastolic
phase of cardiac cycle,thereby limiting
cardiac motion artifact.
28. Cine imaging
Cine imaging or cine MRI, are a type of MRI
sequence acquired to capture motion
For the heart, this is achieved by acquisition at
multiple time points throughout the cardiac
cycle, after synchronisation with the ECG has
been achieved.
Separate k-spaces are assigned to different
phases or segments of the cardiac cycle.
Images are reconstructed from each k-
space and shown in a movie.
This type of imaging technique requires fast
imaging techniques using very short repetition
and echo times such as balanced steady-state
free precession or spoiled gradient
32. Contrast-enhanced techniques
Perfusion imaging (also known as first-pass images)
These are T1 weighted, gradient-echo
sequences. Image acquisition is performed 3 minutes
after gadolinium contrast administration. If there is a
hypoenhanced area, this implies a zone of
myocardial infarction that is non-viable.
Viability study delayed (also known as myocardial
enhancement study)
These are T1 weighted, gradient-echo
sequences. Image acquisition is performed 10 minutes
after gadolinium contrast administration.
Focal myocardial fibrosis has a delayed gadolinium
contrast wash out. So hyperenhancement indicates a
myocardial scar, thus an evolved myocardial
infarction.
36. The two main planes used for cardiac
MRI include the body (scanner) planes
and the cardiac planes.
Body Planes
Body planes are oriented orthogonal to
the long axis of the body and consist
of axial, sagittal, and coronal planes .
37. The axial plane can depict the four
chambers of the heart and the
pericardium simultaneously.
The sagittal plane can show the great
vessels arising in continuity from the
ventricles.
The coronal plane can be used to
assess the left ventricular outflow
tract, the left atrium, and the
pulmonary veins.
39. Cardiac planes
The standard cardiac planes are
established using the scout images
and include
short axis view
horizontal long axis (four-chamber view)
vertical long axis (two-chamber view)
40. These planes are prescribed along a line
extending from the cardiac apex to the
center of the mitral valve (long axis of the
heart) using the axial body plane images.
The short-axis plane extends perpendicular
to this true long axis of the heart at the level
of the mid left ventricle.
The horizontal long(4 chamber) axis is
generated by selecting the horizontal plane
that is perpendicular to the short axis
The vertical long (2 chamber)axis is
prescribed along a vertical plane orthogonal
to the short-axis plane
42. Short axis view
The short-axis plane extends
perpendicular to this true long axis of
the heart at the level of the mid left
ventricle
44. Two chamber view
To achieve a two-chamber scout view,
a true axial view through the left
ventricle should be obtained, and then
an oblique coronal scout view should
be positioned parallel to the
interventricular septum
46. 4 chamber view
The horizontal long axis(4 chamber
view) is generated by selecting the
horizontal plane that is perpendicular
to the short axis
48. Left ventricular outflow view
To obtain a long-axis left ventricular
view, an imaging plane should be
positioned from the left ventricular
apex through the mitral valve by using
a two-chamber view depicting the
mitral valve