U.S. patent application number 12/254630 was filed with the patent office on 2010-04-22 for apparatus and method for detecting and classifying atherosclerotic plaque hemorrhage.
Invention is credited to J. Kevin DeMarco, Anthony T. Vu, David C. Zhu.
Application Number | 20100097061 12/254630 |
Document ID | / |
Family ID | 42108152 |
Filed Date | 2010-04-22 |
United States Patent
Application |
20100097061 |
Kind Code |
A1 |
Zhu; David C. ; et
al. |
April 22, 2010 |
APPARATUS AND METHOD FOR DETECTING AND CLASSIFYING ATHEROSCLEROTIC
PLAQUE HEMORRHAGE
Abstract
A system and method for detecting atherosclerotic plaque
hemorrhage includes a controller programmed to apply a
non-selective inversion recovery RF pulse to a region of interest,
apply a plurality of encoding sequences to the region of interest
to cause generation of a plurality of echoes during application of
each encoding sequence. The controller is further programmed to
acquire three dimensional MR data from the region of interest
during generation of each of the plurality of echoes, identify a
hemorrhage based on the three dimensional MR data, characterize a
type of the hemorrhage, and reconstruct an image based on the three
dimensional MR data, the image comprising the characterized
hemorrhage.
Inventors: |
Zhu; David C.; (East
Lansing, MI) ; DeMarco; J. Kevin; (Okemus, MI)
; Vu; Anthony T.; (Waukesha, WI) |
Correspondence
Address: |
ZIOLKOWSKI PATENT SOLUTIONS GROUP, SC (GEMS)
136 S WISCONSIN ST
PORT WASHINGTON
WI
53074
US
|
Family ID: |
42108152 |
Appl. No.: |
12/254630 |
Filed: |
October 20, 2008 |
Current U.S.
Class: |
324/309 ;
600/410 |
Current CPC
Class: |
A61B 5/02007 20130101;
G01R 33/5615 20130101; G01R 33/5602 20130101; A61B 5/7264 20130101;
G01R 33/5635 20130101; G01R 33/5607 20130101; G01R 33/50 20130101;
A61B 5/055 20130101 |
Class at
Publication: |
324/309 ;
600/410 |
International
Class: |
G01R 33/483 20060101
G01R033/483; A61B 5/055 20060101 A61B005/055 |
Claims
1. A magnetic resonance imaging (MRI) apparatus comprising: a
plurality of gradient coils positioned about a bore of a magnet,
and an RF transceiver system controlled by a pulse module to
transmit RF signals to an RF coil assembly; and a controller
coupled to the plurality of gradient coils and the RF transceiver
system and programmed to: apply a non-selective inversion recovery
RF pulse to a region of interest; apply a plurality of encoding
sequences to the region of interest to cause the generation of a
plurality of echoes during each encoding sequence; acquire three
dimensional magnetic resonance (MR) data from the region of
interest; identify a hemorrhage based on the three dimensional MR
data; characterize a type of the hemorrhage; and reconstruct an
image based on the three dimensional MR data, the image comprising
the characterized hemorrhage.
2. The MRI apparatus of claim 1 wherein identifying the hemorrhage
comprises calculating a T2* mapping based on a semi-log linear
regression of voxel signal values in the three dimensional MR data
and from echo times corresponding to the voxel signal values.
3. The MRI apparatus of claim 2 wherein the T2* mapping is
calculated using at least two echo time points and according to the
relationship: 1/T2*=-[1nS.sub.n-1nS.sub.m)/(TE.sub.n-TE.sub.m)],
where S.sub.n and S.sub.m are voxel signal intensity at TE values
of TE.sub.n and TE.sub.m, respectively.
4. The MRI apparatus of claim 2 wherein the controller is further
programmed to characterize the hemorrhage based on the T2* mapping
as one of a Type I hemorrhage, a Type II hemorrhage, and a non-Type
I hemorrhage.
5. The MRI apparatus of claim 1 wherein reconstructing the image
comprises reconstructing a weighted-average image based on the
three dimensional MR data acquired from the plurality of echoes
during application of each encoding sequence.
6. The MRI apparatus of claim 5 wherein reconstructing the
weighted-average image comprises calculating a signal weighted
average, S.sub.ave according to: i = 1 m ( S i .times. ( S i j = 1
m S j ) ) , ##EQU00002## where m is the number of the plurality of
echoes and where S.sub.i and S.sub.j represent the signal at
TE.sub.i and TE.sub.j, respectively.
7. The MRI apparatus of claim 1 wherein the controller is further
programmed to delay a predetermined time between applying the
non-selective inversion recovery RF pulse and applying a first of
the plurality of encoding sequences.
8. The MRI apparatus of claim 7 wherein the controller is further
programmed to calculate the predetermined time based on a time
between applying the non-selective inversion recovery RF pulse and
apply an encoding sequence of the plurality of encoding sequences
configured to acquire MR data in a center of k-space such that
signals from blood are suppressed in the region of interest.
9. The MRI apparatus of claim 1 wherein the controller is further
programmed to determine an ordering sequence for the plurality of
encoding sequences.
10. The MRI apparatus of claim 9 wherein determining the ordering
sequence comprises determining one of a sequential encoding
ordering sequence, a centric slice encoding ordering sequence, a
sequential phase encoding ordering sequence, a centric phase
encoding ordering sequence, and elliptical centric ordering
sequence, and a radial fan beam centric encoding ordering
sequence.
11. A method for detecting an atherosclerotic plaque hemorrhage
comprising: applying a non-selective inversion recovery RF pulse
toward a subject to be imaged; generating a plurality of echoes
from the subject during each of a plurality of encoding sequences;
acquiring magnetic resonance (MR) data during generation of each
echo; generating a three dimensional MR data set from the acquired
MR data; identifying and characterizing a hemorrhage based on the
three dimensional MR data set, wherein identifying the hemorrhage
comprises generating a T2* map from echo times corresponding to
voxel signal values in the three dimensional MR data set and based
on a semi-log linear regression of the voxel signal values; and
generating an image showing the hemorrhage.
12. (canceled)
13. The method of claim 11 wherein generating the T2* map comprises
calculating the T2* map based on a semi-log linear regression of
multiple echo time points according to a relationship given by:
1/T2*=-[(1nS.sub.n-1nS.sub.m)/(TE.sub.n-TE.sub.m)], where S.sub.n
and S.sub.m are voxel signal intensity at TE values of TE.sub.n and
TE.sub.m, respectively.
14. The method of claim 11 wherein generating the image comprises
reconstructing a weighted-average image using a formula given by: i
= 1 m ( S i .times. ( S i j = 1 m S j ) ) , ##EQU00003## where m is
the number of the plurality of echoes and where S.sub.i and S.sub.j
represent the signal at TE.sub.i and TE.sub.j, respectively.
15. The method of claim 11 further comprising delaying a
predetermined time between generating the non-selective inversion
recovery RF pulse and generating a first echo during a first of the
plurality of encoding sequences to suppress blood signals in the
acquired MR data.
16. The method of claim 15 further comprising: delaying a
predetermined rest time after generating a last echo during a last
of the plurality of encoding sequences; applying a second
non-selective inversion recovery RF pulse toward the subject to be
imaged after delaying the predetermined rest time; generating a
second plurality of echoes from the subject during each of a second
plurality of encoding sequences; acquiring MR data during
generation of each echo of the second plurality of echoes; and
filling a portion of the three dimensional MR data set with the MR
data acquired during generation of each echo of the second
plurality of echoes.
17. The method of claim 11 further comprising highlighting the
hemorrhage in the image.
18. A computer readable storage medium having stored thereon a
computer program comprising instructions, which when executed by a
computer, cause the computer to: apply a non-selective inversion
recovery RF pulse to a region of interest; apply a plurality of
multi-echo encoding sequences to the region of interest; acquire
magnetic resonance (MR) data from a plurality of echoes generated
in the region of interest during each multi-echo encoding sequence;
locate and classify hemorrhage information based on the acquired MR
data; and reconstruct an image comprising the located
hemorrhage.
19. The computer readable storage medium of claim 18 having further
instructions to cause the computer to generate a T2* map based on a
semi-log linear regression of multiple echo time points according
to a relationship given by:
1/T2*=-[(1nS.sub.n-1nS.sub.m)/(TE.sub.n-TE.sub.m)], where S.sub.n
and S.sub.m are voxel signal intensity at TE values of TE.sub.n and
TE.sub.m, respectively.
20. The computer readable storage medium of claim 19 wherein the
instructions that cause the computer to classify hemorrhage
information cause the computer to classify the located hemorrhage
based on the T2* map as one of a Type I hemorrhage, a Type II
hemorrhage, and a non-Type I hemorrhage.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates generally to magnetic resonance (MR)
imaging and, more particularly, to an apparatus and method for
detecting and classifying atherosclerotic plaque hemorrhage.
[0002] When a substance such as human tissue is subjected to a
uniform magnetic field (polarizing field B.sub.0), the individual
magnetic moments of the spins in the tissue attempt to align with
this polarizing field, but precess about it in random order at
their characteristic Larmor frequency. If the substance, or tissue,
is subjected to a magnetic field (excitation field B.sub.1) which
is in the x-y plane and which is near the Larmor frequency, the net
aligned moment, or "longitudinal magnetization", M.sub.Z, may be
rotated, or "tipped", into the x-y plane to produce a net
transverse magnetic moment M.sub.t. A signal is emitted by the
excited spins after the excitation signal B.sub.1 is terminated and
this signal may be received and processed to form an image.
[0003] When utilizing these signals to produce images, magnetic
field gradients (G.sub.x, G.sub.y, and G.sub.z) are employed.
Typically, the region to be imaged is scanned by a sequence of
measurement cycles in which these gradients vary according to the
particular localization method being used. The resulting set of
received NMR signals are digitized and processed to reconstruct the
image using one of many well known reconstruction techniques.
[0004] Carotid plaque hemorrhage has been associated with increased
plaque progression and increased risk of future stroke/transient
ischemic attacks. Detection, identification, and classification of
atherosclerotic plaque hemorrhage may allow a treatment plan to be
developed for a patient having an atherosclerotic plaque hemorrhage
such that negative risks associated therewith may be minimized.
[0005] It would therefore be desirable to have a system and method
capable of detecting and classifying atherosclerotic plaque
hemorrhage.
BRIEF DESCRIPTION OF THE INVENTION
[0006] In accordance with one aspect of the invention, a magnetic
resonance (MR) imaging apparatus includes a plurality of gradient
coils positioned about a bore of a magnet, and an RF transceiver
system controlled by a pulse module to transmit RF signals to an RF
coil assembly. A controller is included and programmed to apply a
non-selective inversion recovery RF pulse to a region of interest
and to apply a plurality of encoding sequences to the region of
interest to cause generation of a plurality of echoes during each
encoding sequence. The computer is further programmed to acquire
three dimensional MR data from the region of interest during
generation of each of the plurality of echoes, identify a
hemorrhage based on the three dimensional MR data, characterize a
type of the hemorrhage, and reconstruct an image based on the three
dimensional MR data, the image comprising the characterized
hemorrhage.
[0007] In accordance with another aspect of the invention, a method
for detecting an atherosclerotic plaque hemorrhage includes
applying a non-selective inversion recovery RF pulse toward a
subject to be imaged, generating a plurality of echoes from the
subject during each of a plurality of encoding sequences, and
acquiring magnetic resonance (MR) data during generation of each
echo. The method also includes generating a three dimensional MR
data set from the acquired MR data, identifying and characterizing
a hemorrhage based on the three dimensional MR data set, and
generating an image showing the hemorrhage.
[0008] In accordance with another aspect of the invention, a
computer readable storage medium having stored thereon a computer
program comprising instructions, which when executed by a computer,
cause the computer to apply a non-selective inversion recovery RF
pulse to a region of interest and apply a plurality of multi-echo
encoding sequences to the region of interest. The computer is
further caused to acquire magnetic resonance (MR) data from a
plurality of echoes generated in the region of interest during each
multi-echo encoding sequence, locate and classify hemorrhage
information based on the acquired MR data, and reconstruct an image
comprising the located hemorrhage.
[0009] Various other features and advantages will be made apparent
from the following detailed description and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The drawings illustrate embodiments presently contemplated
for carrying out the invention.
[0011] In the drawings:
[0012] FIG. 1 is a schematic block diagram of an exemplary MR
imaging system for use with embodiments of the invention.
[0013] FIG. 2 is an imaging sequence diagram according to an
embodiment of the invention.
[0014] FIG. 3 is a multi-echo acquisition pulse sequence diagram
according to an embodiment of the invention.
[0015] FIG. 4 is a flowchart showing a technique for detecting and
classifying an atherosclerotic plaque hemorrhage according to an
embodiment of the invention.
DETAILED DESCRIPTION
[0016] Referring to FIG. 1, the major components of a preferred
magnetic resonance imaging (MRI) system 10 incorporating an
embodiment of the invention are shown. The operation of the system
is controlled from an operator console 12 which includes a keyboard
or other input device 13, a control panel 14, and a display screen
16. The console 12 communicates through a link 18 with a separate
computer system 20 that enables an operator to control the
production and display of images on the display screen 16. The
computer system 20 includes a number of modules which communicate
with each other through a backplane 20a. These include an image
processor module 22, a CPU module 24 and a memory module 26 that
may include a frame buffer for storing image data arrays. The
computer system 20 communicates with a separate system control 32
through a high speed serial link 34. The input device 13 can
include a mouse, joystick, keyboard, track ball, touch activated
screen, light wand, voice control, or any similar or equivalent
input device, and may be used for interactive geometry
prescription.
[0017] The system control 32 includes a set of modules connected
together by a backplane 32a. These include a CPU module 36 and a
pulse generator module 38 which connects to the operator console 12
through a serial link 40. It is through link 40 that the system
control 32 receives commands from the operator to indicate the scan
sequence that is to be performed. The pulse generator module 38
operates the system components to carry out the desired scan
sequence and produces data which indicates the timing, strength and
shape of the RF pulses produced, and the timing and length of the
data acquisition window. The pulse generator module 38 connects to
a set of gradient amplifiers 42, to indicate the timing and shape
of the gradient pulses that are produced during the scan. The pulse
generator module 38 can also receive patient data from a
physiological acquisition controller 44 that receives signals from
a number of different sensors connected to the patient, such as ECG
signals from electrodes attached to the patient. And finally, the
pulse generator module 38 connects to a scan room interface circuit
46 which receives signals from various sensors associated with the
condition of the patient and the magnet system. It is also through
the scan room interface circuit 46 that a patient positioning
system 48 receives commands to move the patient to the desired
position for the scan.
[0018] The gradient waveforms produced by the pulse generator
module 38 are applied to the gradient amplifier system 42 having
Gx, Gy, and Gz amplifiers. Each gradient amplifier excites a
corresponding physical gradient coil in a gradient coil assembly
generally designated 50 to produce the magnetic field gradients
used for spatially encoding acquired signals. The gradient coil
assembly 50 forms part of a resonance assembly 52 which includes a
polarizing magnet 54 and a whole-body RF coil 56. A transceiver
module 58 in the system control 32 produces pulses which are
amplified by an RF amplifier 60 and coupled to the RF coil 56 by a
transmit/receive switch 62. The resulting signals emitted by the
excited nuclei in the patient may be sensed by the same RF coil 56
and coupled through the transmit/receive switch 62 to a
preamplifier 64. The amplified MR signals are demodulated,
filtered, and digitized in the receiver section of the transceiver
58. The transmit/receive switch 62 is controlled by a signal from
the pulse generator module 38 to electrically connect the RF
amplifier 60 to the coil 56 during the transmit mode and to connect
the preamplifier 64 to the coil 56 during the receive mode. The
transmit/receive switch 62 can also enable a separate RF coil (for
example, a surface coil) to be used in either the transmit or
receive mode.
[0019] The MR signals picked up by the RF coil 56 are digitized by
the transceiver module 58 and transferred to a memory module 66 in
the system control 32. A scan is complete when an array of raw
k-space data has been acquired in the memory module 66. This raw
k-space data is rearranged into separate k-space data arrays for
each image to be reconstructed, and each of these is input to an
array processor 68 which operates to Fourier transform the data
into an array of image data. This image data is conveyed through
the serial link 34 to the computer system 20 where it is stored in
memory. In response to commands received from the operator console
12, this image data may be archived in long term storage or it may
be further processed by the image processor 22 and conveyed to the
operator console 12 and presented on the display 16.
[0020] FIG. 2 shows an imaging sequence diagram according to an
embodiment of the invention. Sequence 100 illustrates an Inversion
Recovery prepared Fast SPoiled Gradient Recalled sequence with
Multiple Echoes (IR FSPGR ME). Sequence 100 includes a
non-selective inversion recovery (IR) RF pulse 102 followed by a
plurality of multi-echo encoding sequences 104, each encoding
sequence having a plurality of pulses designed to excite multiple
echoes from a region of interest as discussed below with respect to
FIG. 3. Fat suppression technique (chemical selective saturation,
water-excitation, n-points Dixon decomposition, etc.) can be
employed to suppress signal contribution from fat. In an embodiment
of the invention, sequence 100 is a three-dimensional (3D),
T1-weighted imaging sequence, and encoding sequences 104 are
arranged according to an ordering sequence. For example, as shown,
encoding sequences 104 are arranged according to a sequential slice
encoding ordering sequence such that an encoding sequence 106 that
acquires data for a central region of k-space it is centrally
positioned among the plurality of encoding sequences 104.
[0021] A delay 108 (e.g., a TIprep delay) between application of
non-selective IR RF pulse 102 and a first encoding sequence 110 of
the plurality of multi-echo encoding sequences 104 may be
calculated to optimally determine and select a time of inversion
(TI) 112 such that signals from blood are suppressed. A rest time
114 after application of a last encoding sequence 116 of the
plurality of multi-echo encoding sequences 104 may be optimally
determined and selected along with the time of inversion 112 to
further minimize signal from a blood flow during MR data
acquisition to increase contrast between, for example, a vessel
lumen (not shown) and a vessel wall (not shown).
[0022] It is contemplated that other ordering sequences may be used
to order encoding sequences 104 instead of the sequential slice
encoding ordering sequence shown in FIG. 2. For example, according
to other embodiments of the invention, encoding sequences 104 may
be ordered according to another desired ordering sequence such as a
centric slice encoding ordering sequence, a sequential phase
encoding ordering sequence, a centric phase encoding ordering
sequence, and elliptical centric ordering sequence, or a radial fan
beam centric encoding ordering sequence. As such, the position of
encoding sequence 106 may vary according to the desired encoding
ordering sequence.
[0023] FIG. 3 shows a multi-echo acquisition pulse sequence 118
according to an embodiment of the invention. Pulse sequence 118
illustrates pulses to be generated in each of the encoding
sequences 104 illustrated in FIG. 1. Following the application of
an RF pulse 120 and Y and Z gradient pulses 122, a plurality of
readout gradients 124 allow acquisition of MR signal data from a
multi-echo acquisition 126 having a plurality of echoes 128, 130,
132, 134 excited from a region of interest. The MR signal data from
each echo 128-134 contribute to a respective full 3D k-space MR
data set. That is, MR signal data from echo 128 contribute to a
first 3D k-space MR data set (not shown), MR signal data from echo
130 contribute to a second 3D k-space MR data set (not shown), MR
signal data from echo 132 contribute to a third 3D k-space MR data
set (not shown), and MR signal data from echo 134 contribute to a
fourth 3D k-space MR data set (not shown). Embodiments of the
invention may include acquiring MR data from two, three, four, or
more echoes in multi-echo acquisition 126. Accordingly, a
respective two, three, four, or more 3D k-space MR data sets may be
filled.
[0024] A plurality of spoiler gradients 136 may be applied after
acquiring MR data from echoes 128-134 to destroy transverse
magnetization prior to application of a next excitation pulse 120.
However, while FIGS. 2 and 3 show an IR FSPGR ME sequence, it is
contemplated that an IR non-spoiled prepared gradient recalled echo
sequence, combined with multi-echo acquisition as described above,
may be used to suppress signals from blood instead. Alternatively,
it is contemplated that a Steady State Free Precession (SSFP)
sequence or a Balanced Steady State Free Precession (b-SSFP)
sequence, combined with multi-echo acquisition as described above,
may instead be used to suppress signals from blood. While FIG. 3
shows an implementation of multi-echo acquisition using a bi-polar
read-out gradient, it is contemplated that a unipolar read-out
gradient may also be used for multi-echo acquisition according to
an embodiment of the invention.
[0025] Referring to FIGS. 2 and 3, each application of multi-echo
acquisition pulse sequence 118 results in the filling of one line
of each 3D k-space MR data set. For example, according to one
embodiment of the invention, each application of sequence 118
results in the filling of one line of each of the first, second,
third, and fourth 3D k-space MR data sets using data acquired from
echoes 128-134, respectively. Each application of sequence 100 may
result in, for example, the filling of a complete slice of MR data
for each of the first, second, third, and fourth 3D k-space MR data
sets. Sequence 100 is repeatedly applied to a region of interest
for acquiring and filling a complete first, second, third, and
fourth 3D MR data set corresponding to matrix size.
[0026] FIG. 4 shows a technique 138 for detecting and classifying
an atherosclerotic plaque hemorrhage according to an embodiment of
the invention. Technique 138 begins at block 140 with prescribing
scan data. Prescribing scan data includes determining pulse
sequence parameters for the pulse sequence(s) to be used, for
example, the pulse sequences 100, 118 shown in FIGS. 2 and 3.
Determining the pulse sequence parameters can include, for example,
determining an encoding sequence, such as those described above,
for the plurality of multi-echo encoding sequences 104 and
determining a time of inversion 112 such that signals from blood
are suppressed during MR data acquisition. A delay 108 may also be
prescribed to appropriately select the time of inversion 112 for
the determined encoding sequence. Furthermore, a rest time 114 may
also be prescribed to further minimize signal from a blood flow
during MR data acquisition as described above. Prescribing scan
data also includes determining a number of signals to be acquired
in multi-echo acquisition 126 from the imaging subject. As
described above, the number of signals to be acquired in multi-echo
acquisition 126 relates to the number of 3D, T1-weighted k-space MR
data sets to be filled.
[0027] Following the prescription of scan data at block 140, MR
data is acquired from a region of interest at block 142 via the
application of the pulse sequences 100, 118 (shown in FIGS. 2 and
3) for which the parameters have been prescribed at block 140. For
example, the pulse sequences prescribed at block 140 are applied
according to the prescribed scan data. A T2* map is calculated at
block 144 based on the semi-log linear regression of the voxel
signal values and the corresponding echo times (TE), such as
TE.sub.i, TE.sub.2, TE.sub.3, and TE.sub.4 shown in FIG. 3,
according to the equation:
1/T2*=-[(1nS.sub.n-1nS.sub.m)/(TE.sub.n-TE.sub.m)] (Eqn. 1),
where S.sub.n, and S.sub.m are voxel signal intensity at TE values
of TE.sub.n and TE.sub.m, respectively.
[0028] A weighted-average image is reconstructed at block 146 for
the number of 3D, T1-weighted MR data sets that have been filled.
Weighted-averaging includes calculating a signal weighted average,
S.sub.ave, for each voxel in the weighted-average image according
to:
i = 1 m ( S i .times. ( S i j = 1 m S j ) ) , ( Eqn . 2 )
##EQU00001##
where m is the number of the plurality of echoes and where S.sub.i
and S.sub.j represent the signal at TE.sub.i and TE.sub.j,
respectively. For example, obtaining the signal weighted average,
S.sub.ave, from a two-echo sequence according to Eqn. 2 may be
calculated by:
S.sub.ave=S.sub.1.times.(S.sub.1/S.sub.2))+S.sub.2.times.(S.sub.2/(S.sub-
.1+S.sub.2)) (Eqn. 3).
For a three-echo sequence, obtaining the signal weighted average,
S.sub.ave, according to Eqn. 2 may be calculated by:
S.sub.ave=S.sub.1.times.(S.sub.1/(S.sub.1+S.sub.2+S.sub.3))+S.sub.2.time-
s.(S.sub.2/(S.sub.1+S.sub.2+S.sub.3))+S.sub.3.times.(S.sub.3/(S.sub.1+S.su-
b.2+S.sub.3)) (Eqn. 4).
The weighted averaging helps to increase signal-to-noise ratio
(SNR) and the reconstructed image and emphasize is the signal at
TE.sub.1, or at the first echo, to maintain the ability of
hemorrhage detection.
[0029] At block 148, a hemorrhage in the reconstructed
weighted-average image is detected and classified or characterized
based on the calculated T2* map. According to an embodiment of the
invention, a hemorrhage is classified as a Type I hemorrhage, a
Type II hemorrhage, or a non-Type I hemorrhage. A Type I hemorrhage
has been correlated with, for example, ipsilateral carotid
symptoms. Following classification of the hemorrhage, the
hemorrhage is shown at block 150 in the reconstructed
weighted-average image to a user. In one embodiment, the
hemorrhagic region may be identified or highlighted with T2* color
coding scheme overlaid with the reconstructed image.
[0030] According to an embodiment of the invention, computer system
20 of FIG. 1 may be programmed according to technique 138 for the
automatic detection and classification of hemorrhages. However, it
is contemplated that a computer remote from MR system 10 as shown
in FIG. 1 may also be similarly programmed.
[0031] Embodiments of the invention allow for the detection and
characterization of hemorrhage types in one sequence, which may be
referred to as optimized 3D Spoiled gradient for Hemorrhage
assessment using INversion recovery and multiple Echoes (3D SHINE).
Accordingly, scan time efficiency is improved, and image
mis-registration may be eliminated. Plaque visualization is also
improved due to an improved SNR achieved through embodiments of the
invention.
[0032] In accordance with one embodiment of the invention, a
magnetic resonance (MR) imaging apparatus includes a plurality of
gradient coils positioned about a bore of a magnet, and an RF
transceiver system controlled by a pulse module to transmit RF
signals to an RF coil assembly. A controller is included and
programmed to apply a non-selective inversion recovery RF pulse to
a region of interest and to apply a plurality of encoding sequences
to the region of interest to cause generation of a plurality of
echoes during each encoding sequence. The computer is further
programmed to acquire three dimensional MR data from the region of
interest during generation of each of the plurality of echoes,
identify a hemorrhage based on the three dimensional MR data,
characterize a type of the hemorrhage, and reconstruct an image
based on the three dimensional MR data, the image comprising the
characterized hemorrhage.
[0033] In accordance with another embodiment of the invention, a
method for detecting an atherosclerotic plaque hemorrhage includes
applying a non-selective inversion recovery RF pulse toward a
subject to be imaged, generating a plurality of echoes from the
subject during each of a plurality of encoding sequences, and
acquiring magnetic resonance (MR) data during generation of each
echo. The method also includes generating a three dimensional MR
data set from the acquired MR data, identifying and characterizing
a hemorrhage based on the three dimensional MR data set, and
generating an image showing the hemorrhage.
[0034] In accordance with another embodiment of the invention, a
computer readable storage medium having stored thereon a computer
program comprising instructions, which when executed by a computer,
cause the computer to apply a non-selective inversion recovery RF
pulse to a region of interest and apply a plurality of multi-echo
encoding sequences to the region of interest. The computer is
further caused to acquire magnetic resonance (MR) data from a
plurality of echoes generated in the region of interest during each
multi-echo encoding sequence, locate and classify hemorrhage
information based on the acquired MR data, and reconstruct an image
comprising the located hemorrhage.
[0035] The invention has been described in terms of the preferred
embodiment, and it is recognized that equivalents, alternatives,
and modifications, aside from those expressly stated, are possible
and within the scope of the appending claims.
* * * * *