Transcript TOF法とFSBB法の組み合わせによるhybrid MRA の初期臨床応用

Consecutive Acquisition of Timeresolved Contrast-enhanced MRA and
Perfusion MR Imaging of Brain Tumors
with a Contrast Dose of 16 mL
Kazuhiro Tsuchiya, M.D., Masamichi Imai, M.D.
Maiko Yoshida, M.D., Hidekatsu Tateishi, M.D., Toshiaki Nitatori, M.D.
Department of Radiology, Kyorin University Faculty of Medicine
Mitaka, Tokyo, Japan
Background
In the diagnosis of brain tumors, perfusion MR imaging (PWI) can
show tumor hemodynamics closely related to vascularity and
tumor grade
Aronen HJ, Radiology 1994; Sugahara T, AJR 1994; Knoop EA, Radiology 1999
Time-resolved contrast-enhanced MRA (TCMRA) is another
technique that can demonstrate tumor hemodynamics similarly to
conventional angiography
Yoshikawa T, Eur Radiol 2000; Zou Z, J Magn Reson Imaging 2008
Because of NSF, it is recommended to use a required minimum
dose of Gd-based contrast media when its use is indicated
Purpose
To assess the feasibility and value of consecutive acquisition
of PWI and TCMRA in patients with brain tumor in one
session using a 16-mL total dose of Gd-based contrast
material
This dose was chosen as a 17-mL package of a kind of Gdbased contrast agent (ProHance, Bracco, Milan, Italy) is
available in our country as well as in many other countries
Subjects
28 consecutive patients with brain tumor
14 males and 14 females
age range, 28-82 years (average, 61.3 years)
- high-grade glioma, 8 pts; low-grade glioma, 1 pt;
metastasis, 5 pts; meningioma, 5 pts; lymphoma, 2 pts;
others, 2 pts (esthesioneuroblastoma and cavernous
hemangioma)
- unproven, 5 pts
body weight range, 45-82 kg (average, 58.9 kg)
Methods-1 (Imaging Technique)
MR imager:
1.5-T system (EXCELART Vantage, Toshiba Medical Systems,
Tochigi, Japan)
Imaging protocol:
1) Conventional precontrast sequences
T1WI, T2WI, FLAIR, and DWI
2) TCMRA (3D fast gradient-echo sequence with parallel
imaging and an efficient k-space filling method)
3) PWI (gradient-echo echo-planar sequence)
4) Postcontrast T1WI
Methods-2 (Imaging Technique)
Table 1: Scanning parameters
TCMRA
3D fast field-echo
PWI
gradient-echo EPI
TR (ms)/TE (ms)/flip
angle
3.1/0.9/20
1500/60/90
Section/slab thickness
(mm)
75
5
FOV (mm)
260 x 280
260 x 280
Imaging matrix
128 x 256
128 x 128
Imaging plane
Sagittal, coronal, or axial Axial
Scanning time (sec)
60
60
Postprocessing
<10 min
<1 min
Others
7.5 mm x 10 partitions
10 sections
Sequence
Methods-3 (Imaging Technique)
Contrast injection:
8 mL of Gd-based contrast material and 22 mL of flush saline
at a rate of 3 mL/sec from an antecubital vein using a power
injector for both TCMRA and PWI
Image reconstruction:
1) TCMRA: WS and/or MR imager console
2) PWI: WS (AZE Virtual Place)
Methods-4 (Image Assessment)
(1) Visual assessment of TCMRA and perfusion maps
(rCBF, rCBV, and MTT)
- Grade 1 (poor): tumor was not delineated/contrast with the
normal brain was absent (TCMRA/PWI)
- Grade 2 (fair): tumor was delineated but vascularity and
adjacent vessels were incompletely visualized/ tumor was
delineated but contrast with the normal brain was poor
(TCMRA/PWI)
- Grade 3 (good): tumor vascularity and adjacent vessels were
clearly depicted/ tumor was depicted with good contrast with the
normal brain (TCMRA/PWI)
Determined by consensus of two experienced neuroradiologists
Methods-5 (Image Assessment)
(2) Information additionally obtained by the two
techniques was assessed comparing with the final
pathological diagnosis
Results-1
(1) Visual assessment of TCMRA and perfusion maps
(rCBF, rCBV, and MTT)
In all patients, we obtained TCMRA images and three kinds
of perfusion maps that allowed assessment of tumor
hemodynamics
Table 2: Scores of image assessment
Results-2
(2) Information additionally obtained by the two techniques
Table 3: Comparison between the preoperative Dx and the histological Dx in
23 pts
Note,-GBM indicates glioblastoma; AOA, anaplastic oligoastrocytoma
Case 1: A 68-year-old man with glioblastoma
A
B
C
rCBV (mL/100g)
T2-weighted (A) and postcontrast T1-weighted (B) images suggest glioblastoma. rCBV map (C) shows
elevated CBV compatible with glioblastoma. TCMRA (D) also shows irregular stain and early venous
drainage suggestive of glioblastoma. In this patient, a correct preoperative diagnosis was made without
TCMRA or PWI.
Case 1: A 68-year-old man with glioblastoma
A
B
D
TCMRA
T2-weighted (A) and postcontrast T1-weighted (B) images suggest glioblastoma. rCBV map (C) shows
elevated CBV compatible with glioblastoma. TCMRA (D) also shows irregular stain and early venous
drainage suggestive of glioblastoma. In this patient, a correct preoperative diagnosis was made without
TCMRA or PWI.
Case 2: A 40-year-old woman with metastasis from breast cancer
A
B
C
rCBV (mL/100g)
T2-weighted (A) and postcontrast T1-weighted (B) images show a mass in the left parietal lobe that can be
metastasis or high-grade glioma. rCBV map (C) shows elevated CBV at margins of the mass and TCMRA (D)
also shows a faint stain. Although the preoperative diagnosis was high-grade glioma, the final diagnosis after
surgery was metastasis from breast cancer. In retrospect, findings of TCMRA and PWI may have been
suggestive of metastasis.
Case 2: A 40-year-old woman with metastasis from breast cancer
A
B
D
TCMRA
T2-weighted (A) and postcontrast T1-weighted (B) images show a mass in the left parietal lobe that can be
metastasis or high-grade glioma. rCBV map (C) shows elevated CBV at margins of the mass and TCMRA (D)
also shows a faint stain. Although the preoperative diagnosis was high-grade glioma, the final diagnosis after
surgery was metastasis from breast cancer. In retrospect, findings of TCMRA and PWI may have been
suggestive of metastasis.
Case 3: An 80-year-old man with metastasis from rectal cancer
A
B
C
rCBV (mL/100g)
T2-weighted (A) and postcontrast T1-weighted (B) images show ring-like mass in the cerebellar vermis
that can be metastasis or high-grade glioma. rCBV map (C) shows slightly elevated CBV at margins and
TCMRA (D) also shows a very faint stain. These findings are suggestive of metastasis. The final diagnosis
after surgery was metastasis from rectal cancer. In this patient, a correct diagnosis of metastasis was
made with findings of TCMRA and PWI
Case 3: An 80-year-old man with metastasis from rectal cancer
A
B
D
T2-weighted (A) and postcontrast T1-weighted (B) images show ring-like mass in the cerebellar vermis
that can be metastasis or high-grade glioma. rCBV map (C) shows slightly elevated CBV at margins and
TCMRA (D) also shows a very faint stain. These findings are suggestive of metastasis. The final diagnosis
after surgery was metastasis from rectal cancer. In this patient, a correct diagnosis of metastasis was
made with findings of TCMRA and PWI
Discussion-1
Our basic idea was that, if the same amount of contrast material was
employed, it was preferable to use it in a manner that could provide more
diagnostic information in establishing the diagnosis. In this regard, we
confirmed that, by using 8 mL each, consecutive acquisition of TCMRA and
PWI could yield images of sufficient diagnostic value
As for PWI, it has been reported that, as extravasation of contrast agent due
to disruption of the blood-brain barrier occurs in some tumors, the
administration of a predose of Gd-based contrast material is effective to
prevent artificial lowered estimation of rCBV (Boxermann JL, AJNR 2006).
Although there is a study that reported that no significant difference between
PWIs with and without a predose (Spampinato MV, Neuroradiology 2006),
our study order (TCMRA followed by PWI) may have worked well in this
regard
Discussion-2
In six of the 23 patients with histological diagnosis (26.1%), TCMRA and/or
PWI contributed to the glioma grading or making the differential diagnosis.
In 13 patients (56.5%), however, conventional MR findings were sufficient to
make the correct diagnosis and no additional information was obtained by
TCMRA and/or PWI. Therefore, although in a limited part of the patient
group, the two techniques provided valuable additional information in the
differential diagnosis without additional contrast administration
Conclusion
It is possible to consecutively perform TCMRA and PWI in
this order using 8 mL each of Gd-based contrast material.
The two techniques can provide images that facilitate the
preoperative differential diagnosis of brain tumors