Aims and objectives
Current medical practice involves extensive use ofnon-invasive imagingtechniques,
such as magnetic resonance (MR),
computed tomography (CT),
andmetabolic(PET)imaging,
especially among the oncologic patients.Several studies have hypothesized that tumour characteristics at the cellular and genetic levels are reflected in the phenotypic patterns that canbecaptured with imaging 1,2,3;despitethispromise,
tumour features are often assessed visually and described qualitatively byimaging specialistsandsubjectiveassessment suffersfrom large intra and inter-observer variability4,5,6.
Neverthelesseven biological samplesfailto represent the whole complexity of alesion,
evaluating just a small,
usually random sampled part of the tumor;thereforeimaging tools with potential...
Methods and materials
Phantom and scanners
We imaged an in-house conceived phantom.
No institutional review board approval was required because only a phantom was imaged.
CT scans were repeated,
varying many acquisition parameters (listed in Table 1),
for each of the two scanners we have studied.
A careful registration was carried out to make the images comparable and to translate regions of interest (ROIs),
in order to avoid variations in segmentation.
Extraction of CTTA features
Two-hundred ninety-eight textures analysis parameters (Histogram,
Co-occurence matrix,
Run-lengh matrix and Absolute Gradient...
Results
According to our results the acquisition parameters that mainly influence the variability ofCTTA features aremilliamperageandsection thickness.
By keepingmilliamperage constant we obtained the lowestvariability(Table 2),with an averageQCD of0,065±0,006for scanner A and 0,067±0,010 for scanner B.
Conversely our results showed a somewhat lower advantage in keeping the voltage constant (mean QCD 0,072± 0,0119 for scanner A; 0,087± 0,006 for scanner B).When comparing the scanners independently from acquisition parameters,
only a moderate difference emerged between machines (mean QCD for scanner A: 0,080± 0,100; for scanner B 0,095± 0,160;fig.2and...
Conclusion
Radiomics is an expanding fieldthat aims at identify biomarkersand to unveil information of tumor heterogeneity hidden in medical images,
which could improve diagnosis15,16,
predict clinical outcomeslike response to treatment 17,18and even complications19,20.
Radiomics involves several steps(image acquisition,
segmentation,
feature extraction,
and feature selection) with issuesthathave to befaced; different imageacquisition protocols,
segmentation techniques andprocessing procedures have all been used in previous studies.
This could yield divergent results because of a lack of reproducibility not only between centers,
but also within the same center21,22,23.
CTTA derived features...
Personal information
Gianluca Ficarra,
MD; resident,
department of Diagnostic Imaging and Interventional Radiology,
University of Genoa and S.
Martino Polyclinic,
Genoa
EmanueleBarabino,
MD; resident,
department of Diagnostic Imaging and Interventional Radiology,
University of Genoa and S.
Martino Polyclinic,
Genoa
MartaVerda,
MD; resident,
department of Diagnostic Imaging and Interventional Radiology,
University of Genoa and S.
Martino Polyclinic,
Genoa
SoniaCasella,
MD; resident,
department of Diagnostic Imaging and Interventional Radiology,
University of Genoa and S.
Martino Polyclinic,
Genoa
SimoneCaprioli,
MD; resident,
department of Diagnostic Imaging and Interventional Radiology,
University of...
References
Henriksson E,
Kjellen E,
Wahlberg P,
Ohlsson T,
Wennerberg J,
Brun E.2-Deoxy-2-[18F]Fluoro-D- Glucose Uptake and Correlation to Intratumoral Heterogeneity.Anticancer Research.
2007; 27:2155–2159.
Diehn M,
Nardini C,
Wang DS,
McGovern S,
Jayaraman M,
Liang Y,
Aldape K,
Cha S,
Kuo MD.Identification of noninvasive imaging surrogates for brain tumor gene-expression modules.Proceedings of the National Academy of Sciences.
2008; 105:5213–5218.
Yang X,
Knopp M.Quantifying Tumor Vascular Heterogeneity with Dynamic Contrast-Enhanced Magnetic Resonance Imaging: A Review.Journal of Biomedicine and Biotechnology.
2011; 2011:12.
Mussurakis S,
Buckley DL,
Coady AM,
Turnbull...