Download Dynamic contrast enhanced magnetic resonance

Dynamic contrast enhanced magnetic resonance
imaging (DCE-MRI): Validation of different quantitative
pharmacokinetic models in monitoring neo-adjuvant
treatment in advanced rectal cancer
Poster No.:
C-1547
Congress:
ECR 2010
Type:
Scientific Exhibit
Topic:
GI Tract
Authors:
A. Petrillo, M. Petrillo, M. Sansone, R. Fusco, U. Bracale, A. Siani;
Naples/IT
Keywords:
DCE-MRI, Rectal cancer, Neoadjiuvant treatment
DOI:
10.1594/ecr2010/C-1547
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Purpose
Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) is an concrete
functional technique to evaluate in vivo tumor vascular assessment, now essential to
monitor the response of rectal cancer before and after neo-adjuvant treatment [1-3].
Time intensity (TIC-I/T) curves do not provide a sufficient range of information to
understand all patho-physiological processes that in vivo involve vascular development
during tumor overgrowth [4].
Analyzing data obtained performing multiple T-1w (T-1 Weighted) acquisitions after
Gadolinium (Gd-DTPA) injection and applying pharmacokinetic models on retrieved
values, we evaluated a tumor perfusion approach more capable to summarize contrast
enhancement in terms of quantitative parameters, in order to study rectal cancer affected
patients before and after the neo adjuvant treatment.
Aim of this study was the comparison of multiple quantitative parameters strictly related
to vascular anatomy and essential to establish a possible relationship among DCE-MRI
perfusion data and patient TNM staging or CRM , assessed during rectal cancer neoadjuvant treatments, CEA and CA 19-9 markers.
Methods and Materials
Patients selection and MRI examination technique
We studied eleven (11) rectal cancer affected patients (55-70 y.o.), 5 females and 6
males. All patients were histologically proven.
All patients underwent an MRI study that was performed using a 1,5T scanner and
phased-array coils.
A superparamagnetic iron oxide (SPIO) contrast enema was employed to distend the
rectal lumen and achieve maximal tumor-to-lumen contrast gradient followed by T2-w
tse2D axial, sagittal (TE 98, TR 4980, matrix 464x512, slice thickness 3mm,fixed flip
angle 150°) and T1-w tse2D coronal images (TE 14, TR 500, matrix 512x512, slice
thickness 3mm, fixed flip angle 150°).
The IV administration of 2mL/Kg Gadolinium (Gd-DTPA) was performed and eleven (11)
axial T1-w fl3D acquisitions (TE 4,5, TR 9,8, matrix 512x384, slice thickness 3mm, fixed
flip angle 25°) were obtained.
Sagittal and coronal T1-w TSE (TE 14, TR 500, matrix 512x448, slice thickness 3mm,
fixed flip angle 150°)images, post-contrast injection were acquired, to complete an
accurate TNM staging.
Image analysis
In order to avoid the influence of motion artifacts on data analysis, images were accurately
visually selected and only adequate acquisitions were included in the study.
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All images were evaluated by two blinded expert radiologists, each one with almost 5
years of training in gastronterology imaging.
A region of interest (ROI) was drawn on suspected lesions (5x5 pixels matrix, Fig.1)
before and after neo adjuvant treatments and a TNM patient evaluation followed every
MRI session.
Obtained data were analyzed applying multiple pharmacokinetic models developed by
Brix et al., Tofts and Kermode,Larsson et al., Simpson et al. [5-8], on values retrieved from
ROI drawn on tumor affected tissues followed by comparison among used quantitative
models on same considered ROI. (Fig.2)
For each patient were collected data concerning TNM staging, before and after neoadjuvant treatment.
Statistical analysis
A statistical analysis was made applying t-test and one-way table analysis of variance
(ANOVA), in order to explore the existing relationships among quantitative resulting
parameters and clinical evaluated factors as above.
Images for this section:
Fig. 1: TIC of three ROI selected by an expert radiologist (ROI1,ROI2,ROI3)
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Fig. 2: Comparison among all models.
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Results
We were able to perform a statistical analysis based on data retrieved from calculated
quantitative parameters and TNM.
A significant (p<0.05) difference was found in terms of quantitative DCE-MRI assessment
before and after neo adjuvant treatment corresponding in patients with different TNM that
were shown as afferent to different subsets of population.
Data processed throw models developed by Brix, Tofts and Simpson were able to
distinguish patients with a T2 staging from those with a T3 staging.
Pharmacokinetics models developed by Brix, Larsson, Lawrence made a distinction
between patients with a T2 or a T3 staging from those with a T4 staging.(Fig.1)
Images for this section:
Fig. 1: The null hypothesis is that the two samples belong to the same population. The
tests return the p-value or the probability that the null hypothesis is true. If p-value is >
0.05 the null hypothesis is accepted; if p-value is < 0.05 the null hypothesis is rejected.
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Conclusion
Preliminary results show that not all pharmacokinetic models have the same
performances in characterizing TNM staging in monitoring rectal cancer affected patients
during neo-adjuvant treatments.
Statistically quantitative DCE-MRI measurements made applying Brix model (Ktrans, Kep
and Ve parameters) seem to give superior capabilities in discriminate patients TNM
subset of pertinence, especially in characterizing patients with a T2 staging from those
with a T3 staging.
This observation, if verified on a bigger sample could adequately support in deciding how
functional DCE-MRI can implement clinical decisions.
Its advantages could be relevant in monitoring rectal cancer affected patient during neoadjuvant treatments, opening new perspectives in getting over the limits that actually
affect MRI examinations with more data able to better calibrate the expected response
to administered therapies.
References
[1] M. A. Zahra, K. G. Hollingsworth, E. Sala, D. J. Lomas, L. T. Tan (2007) Dynamic
contrast-enhanced MRI as a predictor of tumour response to radiotherapy. Lancet Oncol
8:63-74.
[2] L. Bacharach, M. Thomasson (2005) Imaging approaches for monitoring
chemotherapy. Drug Discovery Today: Technologies 2:329-334.
[3] G. De Lussanet, m. R. Padhani, A. van Baardwijk, P. Lambin, L. Beets, A.
Van Engelshoven, H. Beets (2005) Dynamic Contrast-Enhanced Magnetic Resonance
Imaging Of Radiation Therapy-Induced Microcirculation Changes In Rectal Cancer. Int.
J. Radiation Oncology Biol. Phys 63:1309-1315.
[4] Atkin G, Taylor NJ, Daley FM, Stirling JJ, Richman P, Glynne-Jones R, d'Arcy JA,
Collins DJ, Padhani AR (2006) Dynamic contrast-enhanced magnetic resonance imaging
is a poor measure of rectal cancer angiogenesis. Br J Surg. 93(:992-1000.
[5] P. S. Tofts (1997) Modeling Tracer Kinetics in Dynamic Gd-DTPA MR Imaging. J
Magn Reson Imaging 7:91-101
[6] Larsson et al (1996) Myocardial perfusion modeling using MRI. Magn Reson Med
35:716-726.
[7] G. Brix, W. Semmler, R. Port, et al (1991) Pharmacokinetic Parameters in CNS GdDTPA enhanced MR imaging. J. Comput Assist Tomogr 15:621-628
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[8] Simpson NE, He Z, Evelhoch JL (1999) Deuterium NMR tissue perfusion
measurements using the tracer uptake approach: I. Optimization of methods. Magnetic
Resonance Med 42:42 - 52.
Personal Information
Dr. Antonella Petrillo, M.D.
Date of birth: Dec 3, 1956; Place of birth: Caserta
Degree in Medicine and Surgery on July, 24, 1985, "cum laude";
Specialty Degrees: Nuclear Medicine (Dec. 6, 1988); Diagnostic Radiology (Oct. 10,
1994)
All degrees administered by the University of Naples "Federico II", Faculty of Medicine
and Surgery.
Position held:
1992-2001: Medical Radiologist, National Cancer Institute of Naples "Fondazione G.
Pascale", with special interest in Magnetic Resonance Imaging;
2003: Encharged of the High Specialty Degree in MRI imaging, with special reference to
Angio-RMI, Cholangio-RMI, Mammo-RMI, Dynamic studies and interventional RMI.
2007: Nomination as President of a Humanitarian Association for patients "Sinergie
Salute Onlus ", Via Cisterna dell'Olio 10, 80136 Naples.
April 16, 2006. Head of the Simple Operative Structure of Breast Pathology, National
Cancer Institute of Naples.
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