Delta-radiomics increases multicentre reproducibility: a phantom study.

Texture analysis (TA) can provide quantitative features from medical imaging that can be correlated to clinical endpoints. The challenges relevant to robustness of radiomics features have been analyzed by many researchers, as it seems to be influenced by acquisition and reconstruction protocols. Delta-texture analysis (D-TA), conversely, consist in the analysis of TA feature variations at different acquisition times, usually before and after a therapy. Aim of this study was to investigate the influence of different CT scanners and acquisition parameters in the robustness of TA and D-TA. We scanned a commercial phantom (CIRS model 467, Gammex, Middleton, WI, USA), that is used for the calibration of electron density, two times by varying the disposition of plugs, using three different scanners. After the segmentation, we extracted TA features with LifeX and calculated TA features and D-TA features, defined as the variation of each TA parameters extracted from the same position by varying the plugs with the formula (Y-X)/X. The robustness of TA and D-TA features were then tested with intraclass coefficient correlation (ICC) analysis. The reliability of TA parameters across different scans, with different acquisition parameters and ROI positions has shown poor reliability in 12/37 and moderate reliability in the remaining 25/37, with no parameters showing good reliability. The reliability of D-TA, conversely, showed poor reliability in 10/37 parameters, moderate reliability in 10/37 parameters, and good reliability in 17/37 parameters. The comparison between TA and D-TA ICCs showed a significant difference for the whole group of parameters (p:0.004) and for the subclasses of GLCM parameters (p:0.033), whereas for the other subclasses of matrices (GLRLM, NGLDM, GLZLM, Histogram), the difference was not significant. D-TA features seem to be more robust than TA features. These findings reinforce the potentiality for using D-TA features for early assessment of treatment response and for developing tailored therapies. More work is needed in a clinical setting to confirm the results of the present study.

Prognostic Value of MR Imaging Texture Analysis in Brain Non-Small Cell Lung Cancer Oligo-Metastases Undergoing Stereotactic Irradiation.

UNLABELLED: BACKGROUND : Stereotactic irradiation is widely used in brain oligo-metastases treatment. The aim of this study is to evaluate the prognostic value of magnetic resonance imaging (MRI) texture analysis (TA) of brain metastases (BM) of non-small cell lung cancer (NSCLC). MATERIALS AND METHODS : This study included thirty-eight consecutive patients undergoing stereotactic irradiation, that is, stereotactic fractionated radiotherapy (SRT) or radiosurgery (SRS), from January 2011 to December 2014 for 1-2 brain BM from NSCLC. Whole-brain radiotherapy (WBRT) was not delivered. The diagnostic MRI DICOM (Digital Imaging and Communications in Medicine) images were collected and analyzed with a homemade ImageJ macro, and typical TA parameters (mean, standard deviation, skewness, kurtosis, entropy, and uniformity) were evaluated for: brain progression-free survival; modality of brain metastatic progression (local progression or/and new metastases); and overall survival, after SRT/SRS. RESULTS: After SRT/SRS 14 patients (36.8%) experienced recurrence in the brain, with a recurrence in the irradiated site (five patients, 13.2%), new metastases (11 patients, 28.9%), local recurrence and new metastases (two patients, 5.25%). Nineteen patients (50%) died of tumor progression or other causes. Entropy and uniformity were significantly associated with local progression, whereas kurtosis was significantly associated with both local progression and new brain metastases. CONCLUSIONS : These results appear promising, since the knowledge of factors correlated with the modality of brain progression after stereotactic irradiation of brain oligo-metastatic foci of NSCLC might help in driving the best treatment in these patients (association of SRT/SRS with WBRT? Increase of SRT/SRS dose?). Our preliminary data needs confirmation in large patient series.

Localized prostate cancer treated with intensity-modulated radiotherapy.

AIMS AND BACKGROUND: The development and use of new radiotherapy techniques, especially 3D conformal radiotherapy or intensity-modulated radiotherapy, has allowed the safe application of high doses of external beam radiotherapy without increasing toxicity. The aim of this analysis was to describe the acute and when possible late toxicity and the feasibility on using intensity-modulated radiotherapy into our routine work. PATIENTS AND METHODS: From June 2003 to December 2004, 60 patients with prostate cancer underwent high dose (80 Gy) radiotherapy treatment with intensity-modulated radiotherapy at the University of Florence. In the current analysis, we included patients without clinical or radiographic evidence of distant disease at the time of the first evaluation in the radiotherapy unit. RESULTS: Intensity-modulated radiotherapy treatments were delivered successfully without any interruption or technical problem. High-dose intensity-modulated radiotherapy was well tolerated acutely. Four patients (10%) developed grade 1 late rectal toxicity after completion of intensity-modulated radiotherapy and 8 patients (20%) developed grade 1 late urinary symptoms. CONCLUSIONS: Intensity-modulated radiotherapy is the approach of choice for high-dose radiotherapy delivery. No patient had severe toxicity (grade 3) despite the high dose delivered. From a cost-benefit point of view, our experience shows that delivery of intensity-modulated radiotherapy requires only minor corrections to the ordinary activity schedule.