Download Towards time-resolved non-CE MRA with CINEMA

Publication for the
Philips MRI Community
Issue 44 – SUMMER 2011
Towards time-resolved
non-CE MRA with
CINEMA
This article is part of FieldStrength issue 44
Summer 2011
34
Research
Masanobu Nakamura
Towards time-resolved
non-CE MRA with CINEMA
Non-contrast enhanced imaging has gained momentum
over the past years. Newly developed techniques, such as
B-TRANCE, have proven useful in the evaluation of several
diseases1. One aspect that has been lacking though, was
the ability to depict hemodynamic processes. Yaesu clinic,
Chuo-ku, Tokyo, Japan is using an Achieva 3.0T scanner
with special software to perform of non-CE MRA research
in this field2,3. The team led by Masanobu Nakamura,
radiotechnologist, is exploring time-resolved non-CE MRA
in collaboration with Kumamoto University, Kumamoto
Central hospital and Juntendo University Hospital.
Time-resolved non-CE MRA with CINEMA
CINEMA stands for Contrast inherent Inflow Enhanced
Multi-phase Angiography. In order to depict inflow into
the vascular tree, the team has developed an imaging
sequence based on a multi-phase ASL approach using the
FAIR preparation scheme. In this approach, two acquisitions
are performed – one with and one without labeling of the
inflowing blood. The two acquisitions are subsequently
subtracted, resulting in an image where only the inflowing
blood is depicted.
Acquisition 1
global
180°
α
α
α
....
Acquisition 2
Acquisition 2
α
Acquisition 1
....
Subtraction Image
Basic principle of the ASL based CINEMA sequence. Two acquisitions are performed, one
with and one without labeling of the blood. Subtraction of the two images results in an
image of the inflowing blood.
global
180°
TI1
spoiler
T TFE
Phase N
Phase 2
Phase 1
α
Time-resolved information is obtained by performing
a segmented readout, at multiple time points after the
labeling pulse. The temporal resolution can be controlled by
changing the duration of the readout segments. Inflow
of blood into the region of interest can be followed as long
as the label persists.
selective
180°
α
spoiler
T TFE
α
spoiler
T TFE
selective
180°
Phase 1
α
∆TI
TI2
TI3
TIN
TR
Time resolved information is obtained from the multi-phasic readout.
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FieldStrength - Issue 44 - Summer 2011
spoiler
T TFE
TOF MRA
TI=420ms
TI=620ms
TI=820ms
TI=1020ms
Rt-ICAPCA Lt-ICA
TI=1220ms
TOF (left) and CINEMA-FAIR (right)
images acquired from a healthy
volunteer. MIP images are shown
from representative phases in one
subject. Temporal resolution 200 ms,
spatial resolution 1x1x1 mm3,
scan time 6:49 min.
Selective labeling for identification
of supplying arteries
The CINEMA technique may further be extended by the
use of selective labeling slabs. In this way, blood flow from
a particular artery can be selectively visualized. Upper left:
TOF image used for planning of the labeling slabs. Upper
right: Schematic depiction of the labeling slabs. Lower row:
Arterial structures supplied by the right internal carotid
artery (Rt-ICA), posterior communicating artery (PCA),
and left internal carotid artery (Lt-ICA).
Clinical applications
Information on the hemodynamics of blood flow is crucial
in several cerebrovascular diseases, such as arterio-venous
malformations (AVM’s) and Moyamoya disease. Therefore,
CINEMA might potentially play a role in the diagnosis of
these diseases.
TOF MRA
TI=230ms
TI=460ms
TI=690ms
TI=920msTI=1150ms TI=1380ms
References
1 Wyttenbach et al., Radiology
(2007)245;186-195
2. Nakamura et al., Proc. ISMRM
(2011), 3345
3. Nakamura et al., Proc. ISMRM
(2011), 4036
Moyamoya disease
CINEMA TOF (left) and CINEMA-FAIR (right) images in a patient with Moyamoya
disease. The characteristic ‘puff-of-smoke-like’ arterial structures are well depicted.
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