Yoshiharu Ohno1,2, Yuji Kishida2, Shinichiro Seki2, Hisanobu Koyama2, Shigeru Ohyu3, Masao Yui3, Takeshi Yoshikawa1,2, Katsusuke Kyotani4, and Kazuro Sugimura2
1Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Japan, 2Radiology, Kobe University Graduate School of Medicine, Kobe, Japan, 3Toshiba Medical Systems Corporation, Otawara, Japan, 4Center for Radiology and Radiation Oncology, Kobe University Hospital, Kobe, Japan
Synopsis
Quantification of
perfusion parameter from dynamic CE-perfusion MRI at 3T system may be more
difficult than that at 1.5T system, and contrast media concentration may have
larger influence to measurement error of perfusion parameter on a 3T
system. We hypothesized that a bolus
injection protocol with appropriately small contrast media volume can provide
accurate pulmonary perfusion parameter on dynamic CE-perfusion MRI at a 3T
system. The
purpose of this study was to determine the appropriate contrast media volume for
quantitative assessment of dynamic CE-pulmonary MRI, when compared with dynamic
CE-area-detector CT (ADCT) for quantitative evaluation of perfusion within
whole lung.Introduction
Whole lung perfusion evaluation
has been suggested as one of the key functional evaluations in various
pulmonary diseases such as chronic obstructive pulmonary disease (COPD), lung
cancer, and pulmonary vascular diseases.
In the last decade, quantitative assessments of dynamic
contrast-enhanced (CE-) perfusion MR imaging (MRI) at 1.5T MR systems have been
suggested as useful (1-3). On the other
hand, 3T MR systems have been applied in routine clinical practice. However, the 3T MR system has some drawbacks
as compared with the 1.5T MR system (4, 5).
In addition, quantification of perfusion parameter from dynamic
CE-perfusion MRI at a 3T system may be more difficult than that at a 1.5T
system, and contrast media concentration may have larger influence to
measurement error of perfusion parameter on a 3T system.
We hypothesized that a bolus
injection protocol with appropriately small amounts of gadolinium contrast
media can provide accurate pulmonary perfusion parameter on dynamic
CE-perfusion MRI at a 3T system. The purpose of this study was to determine the appropriate
contrast media volume for quantitative assessment of dynamic CE-pulmonary MRI,
when compared with dynamic CE-area-detector CT (ADCT) for quantitative
evaluation of perfusion within whole lung.
Methods and Materials:
17 consecutive patients with suspicious of
small pulmonary nodule and pulmonary emphysema (11 males, 6 females; mean age
72 years) underwent dynamic CE- perfusion ADCT, dynamic CE-perfusion MRI, which
were evaluated by two Gd contrast media volumes as 1.5 ml (protocol A: 0.75mmol) and 3.5 ml (protocol B: 1.75mmol), and %FEV1 measurement. Dynamic CE-perfusion MRI (TR 2.9 ms/ TE 1.1
ms/ flip angle 12 degree, reduction factor 2) in each patient was acquired on a
3T MR scanner (Vantage Titan 3T, Toshiba Medical Systems Corporation, Otawara,
Japan) using a phased-array coil. Dynamic
CE-perfusion ADCT of the entire lung in each patient was also performed on a
320-detector row CT system (Aquilion ONE, Toshiba) with non-helical dynamic
volume scan at two or three different position, and generated dynamic
CE-perfusion ADCT data of the entire lung by using our proprietary
software. All dynamic CE-perfusion MR
and ADCT data were analyzed by dual-input maximum slope method, and total
arterial, pulmonary arterial and systemic arterial perfusion maps were
generated on a pixel-by-pixel basis.
Then regional pulmonary perfusion parameters were determined by ROI
measurements.
To
access the influence of contrast media volume for regional perfusion
assessment, correlations and mean differences of perfusion parameter between
dynamic first-pass CE-perfusion ADCT and MRI assessed by 1.5ml and 3.5ml were
statistically evaluated. To evaluate the
capability for functional assessment, each perfusion parameter was also
correlated with %FEV1. A p
value less than 0.05 was considered as statistically significant in all
statistical analyses.
Results
Representative
case is shown in Figure 1. When correlated with each
perfusion parameter from ADCT data, protocol
A and B had significant and weak correlations
with total (A: r=0.13, p=0.02; B: r=0.12, p=0.03) and pulmonary (A: r=0.16, p=0.003; B: r=0.15, p=0.005) arterial perfusions. Mean differences of all perfusion parameters
of protocol A (total arterial
perfusion: -9.7±41.3ml/100ml/min,
pulmonary arterial perfusion: -15.2±32.0ml/100ml/min, systemic arterial perfusion: 5.5±15.4ml/100ml/min) were
significantly smaller than those of protocol B (total arterial perfusion: 35.5±57.5ml/100ml/min, p<0.0001; pulmonary arterial
perfusion: 27.5±48.3ml/100ml/min,
p<0.0001; systemic arterial perfusion: 8.1±16.7ml/100ml/min, p=0.03). In addition, all perfusion MR parameters with
protocol A (total arterial perfusion:
r=0.60, p=0.02; pulmonary arterial perfusion: r=0.58, p=0.02; systemic arterial
perfusion: r=0.54, p=0.04) and ADCT (total arterial perfusion: r=0.59, p=0.02;
pulmonary arterial perfusion: r=0.61, p=0.02) had significant correlation with
%FEV
1.
Conclusion
Appropriate small contrast media volume for dynamic CE-perfusion
MRI at 3T system provides accurate pulmonary perfusion parameter assessment and
pulmonary functional loss evaluation, when compared with dynamic CE-perfusion
ADCT.
Acknowledgements
No acknowledgement found.References
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