Effects of Guided Random Sampling of TCCs on Blood Flow Values in CT Perfusion Studies of Lung Tumors

Gibaldi, Agostino; Barone, Domenico; Gavelli, Giampaolo; Malavasi, Silvia; Bevilacqua, Alessandro

doi:10.1016/j.acra.2014.08.009

Cited by 24 publications

(9 citation statements)

References 31 publications

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“…Then, for each lesion, the radiologists performed a 3D alignment according to the procedure described in [ 29 ]. In order to obtain the TCCs relative to each voxel, the values of the temporal sequence were fitted using the sigmoid-shape model, arising from the Hill Equation [ 30 ], and the random sampling method described in [ 31 ]. The curve fitting is achieved employing an in-house fitting algorithm based on the nonlinear, least squares, Levenberg-Marquardt minimization algorithm (lsqcurvefit, MATLAB © ; MathWorks, Natick, MA, USA).…”

Section: Methodsmentioning

confidence: 99%

CT Perfusion in Patients with Lung Cancer: Squamous Cell Carcinoma and Adenocarcinoma Show a Different Blood Flow

Bevilacqua

Gavelli

Baiocco

et al. 2018

BioMed Research International

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Objectives To characterize tumour baseline blood flow (BF) in two lung cancer subtypes, adenocarcinoma (AC) and squamous cell carcinoma (SCC), also investigating those “borderline” cases whose perfusion value is closer to the group mean of the other histotype. Materials and Methods 26 patients (age range 36-81 years) with primary Non-Small Cell Lung Cancer (NSCLC), subdivided into 19 AC and 7 SCC, were enrolled in this study and underwent a CT perfusion, at diagnosis. BF values were computed according to the maximum-slope method and unreliable values (e.g., arising from artefacts or vessels) were automatically removed. The one-tail Welch's t-test (p-value <0.05) was employed for statistical assessment. Results At diagnosis, mean BF values (in [mL/min/100g]) of AC group [(83.5 ± 29.4)] are significantly greater than those of SCC subtype [(57.0 ± 27.2)] (p-value = 0.02). However, two central SCCs undergoing artefacts from vena cava and pulmonary artery have an artificially increased mean BF. Conclusions The different hemodynamic behaviour of AC and SCC should be considered as a biomarker supporting treatment planning to select the patients, mainly with AC, that would most benefit from antiangiogenic therapies. The significance of results was achieved by automatically detecting and excluding artefactual BF values.

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Section: Methodsmentioning

confidence: 99%

CT Perfusion in Patients with Lung Cancer: Squamous Cell Carcinoma and Adenocarcinoma Show a Different Blood Flow

Bevilacqua

Gavelli

Baiocco

et al. 2018

BioMed Research International

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“…The technique involves fitting each position trace with a sigmoid (four parameters: position offset, time offset, slope, and amplitude) (Waitzman et al, 1991). We used a RANSAC algorithm (Gibaldi et al, 2015) to find the best sigmoid using data from 50 ms before the preliminary start point to 50 ms after the preliminary endpoint. We defined start points and endpoints, respectively, as the 2% and 98% of the sigmoid.…”

Section: Experiments 1: Oculomotor Horoptermentioning

confidence: 99%

Binocular Eye Movements Are Adapted to the Natural Environment

Gibaldi

Banks

2019

J. Neurosci.

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Humans and many animals make frequent saccades requiring coordinated movements of the eyes. When landing on the new fixation point, the eyes must converge accurately or double images will be perceived. We asked whether the visual system uses statistical regularities in the natural environment to aid eye alignment at the end of saccades. We measured the distribution of naturally occurring disparities in different parts of the visual field. The central tendency of the distributions was crossed (nearer than fixation) in the lower field and uncrossed (farther) in the upper field in male and female participants. It was uncrossed in the left and right fields. We also measured horizontal vergence after completion of vertical, horizontal, and oblique saccades. When the eyes first landed near the eccentric target, vergence was quite consistent with the natural-disparity distribution. For example, when making an upward saccade, the eyes diverged to be aligned with the most probable uncrossed disparity in that part of the visual field. Likewise, when making a downward saccade, the eyes converged to enable alignment with crossed disparity in that part of the field. Our results show that rapid binocular eye movements are adapted to the statistics of the 3D environment, minimizing the need for large corrective vergence movements at the end of saccades. The results are relevant to the debate about whether eye movements are derived from separate saccadic and vergence neural commands that control both eyes or from separate monocular commands that control the eyes independently.

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“…RFs were extracted from PCa ROIs, from both ADC and DWI b2000 sequences. For each slice with lesion, seven first-order RFs, including mean, median, skewness, kurtosis, interquartile range, coefficient of variation [ 22 ] and entropy, were computed on a local tissue patch based on the method proposed in [ 22 , 23 ], in order to account for the small changes of tissue heterogeneity occurring between neighbor voxels. The smallest informative tissue unit for radiomic analysis was chosen to be approximately 1 cm 2 .…”

Section: Methodsmentioning

confidence: 99%

The Primacy of High B-Value 3T-DWI Radiomics in the Prediction of Clinically Significant Prostate Cancer

et al. 2021

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Predicting clinically significant prostate cancer (csPCa) is crucial in PCa management. 3T-magnetic resonance (MR) systems may have a novel role in quantitative imaging and early csPCa prediction, accordingly. In this study, we develop a radiomic model for predicting csPCa based solely on native b2000 diffusion weighted imaging (DWIb2000) and debate the effectiveness of apparent diffusion coefficient (ADC) in the same task. In total, 105 patients were retrospectively enrolled between January–November 2020, with confirmed csPCa or ncsPCa based on biopsy. DWIb2000 and ADC images acquired with a 3T-MRI were analyzed by computing 84 local first-order radiomic features (RFs). Two predictive models were built based on DWIb2000 and ADC, separately. Relevant RFs were selected through LASSO, a support vector machine (SVM) classifier was trained using repeated 3-fold cross validation (CV) and validated on a holdout set. The SVM models rely on a single couple of uncorrelated RFs (ρ < 0.15) selected through Wilcoxon rank-sum test (p ≤ 0.05) with Holm–Bonferroni correction. On the holdout set, while the ADC model yielded AUC = 0.76 (95% CI, 0.63–0.96), the DWIb2000 model reached AUC = 0.84 (95% CI, 0.63–0.90), with specificity = 75%, sensitivity = 90%, and informedness = 0.65. This study establishes the primary role of 3T-DWIb2000 in PCa quantitative analyses, whilst ADC can remain the leading sequence for detection.

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Effects of Guided Random Sampling of TCCs on Blood Flow Values in CT Perfusion Studies of Lung Tumors

Cited by 24 publications

References 31 publications

CT Perfusion in Patients with Lung Cancer: Squamous Cell Carcinoma and Adenocarcinoma Show a Different Blood Flow

CT Perfusion in Patients with Lung Cancer: Squamous Cell Carcinoma and Adenocarcinoma Show a Different Blood Flow

Binocular Eye Movements Are Adapted to the Natural Environment

The Primacy of High B-Value 3T-DWI Radiomics in the Prediction of Clinically Significant Prostate Cancer

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