D. Visvikis

Unité Inserm U1077, Caen, Lower Normandy, France

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Publications (345)625.7 Total impact

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    ABSTRACT: Introduction With 18F-FDG PET/CT, tumor uptake intensity and heterogeneity have been associated with outcome in several cancers. This study aimed at investigating whether 18F-FDG uptake intensity, volume or heterogeneity could predict the outcome in patients with non-small cell lung cancers (NSCLC) treated by stereotactic body radiation therapy (SBRT). Methods Sixty-three patients with NSCLC treated by SBRT underwent a 18F-FDG PET/CT before treatment. Maximum and mean standard uptake value (SUVmax and SUVmean), metabolic tumoral volume (MTV), total lesion glycolysis (TLG), as well as 13 global, local and regional textural features were analysed. The predictive value of these parameters, along with clinical features, was assessed using univariate and multivariate analysis for overall survival (OS), disease-specific survival (DSS) and disease-free survival (DFS). Cutoff values were obtained using logistic regression analysis, and survivals were compared using Kaplan-Meier analysis. Results The median follow-up period was 27.1 months for the entire cohort and 32.1 months for the surviving patients. At the end of the study, 25 patients had local and/or distant recurrence including 12 who died because of the cancer progression. None of the clinical variables was predictive of the out- come, except age, which was associated with DFS (HR 1.1, P = 0.002). None of the 18F-FDG PET/CT or clinical parameters, except gender, were associated with OS. The univariate analysis showed that only dissimilarity (D) was associated with DSS (HR = 0.822, P = 0.037), and that several metabolic measurements were associated with DFS. In multivariate analysis, only dissimilarity was significantly associated with DSS (HR = 0.822, P = 0.037) and with DFS (HR = 0.834, P < 0.01). Conclusion The textural feature dissimilarity measured on the baseline 18F-FDG PET/CT appears to be a strong independent predictor of the outcome in patients with NSCLC treated by SBRT. This may help selecting patients who may benefit from closer monitoring and therapeutic optimization.
    No preview · Article · Jan 2016 · European journal of nuclear medicine and molecular imaging
  • Charalampos Tsoumpas · Dimitris Visvikis · George Loudos

    No preview · Article · Jan 2016 · PET Clinics
  • Mathieu Hatt · Dimitris Visvikis

    No preview · Article · Oct 2015 · Computerized medical imaging and graphics: the official journal of the Computerized Medical Imaging Society
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    ABSTRACT: Purpose: Accurate tumor delineation in positron emission tomography (PET) images is crucial in oncology. Although recent methods achieved good results, there is still room for improvement regarding tumors with complex shapes, low signal-to-noise ratio, and high levels of uptake heterogeneity. Methods: The authors developed and evaluated an original clustering-based method called spatial positron emission quantification of tumor Automatic Lp-norm estimation (SPEQTACLE), based on the fuzzy C-means (FCM) algorithm with a generalization exploiting a Hilbertian norm to more accurately account for the fuzzy and non-Gaussian distributions of PET images. An automatic and reproducible estimation scheme of the norm on an image-by-image basis was developed. Robustness was assessed by studying the consistency of results obtained on multiple acquisitions of the NEMA phantom on three different scanners with varying acquisition parameters. Accuracy was evaluated using classification errors (CEs) on simulated and clinical images. SPEQTACLE was compared to another FCM implementation, fuzzy local information C-means (FLICM) and fuzzy locally adaptive Bayesian (FLAB). Results: SPEQTACLE demonstrated a level of robustness similar to FLAB (variability of 14%9% vs 14%7%, p = 0.15) and higher than FLICM (45%18%, p <0.0001), and improved accuracy with lower CE (14%11%) over both FLICM (29%29%) and FLAB (22%20%) on simulated images. Improvement was significant for the more challenging cases with CE of 17%11% for SPEQTACLE vs 28%22% for FLAB (p = 0.009) and 40%35% for FLICM (p <0.0001). For the clinical cases, SPEQTACLE outperformed FLAB and FLICM (15%6% vs 37%14% and 30%17%, p <0.004). Conclusions: SPEQTACLE benefitted from the fully automatic estimation of the norm on a case-by-case basis. This promising approach will be extended to multimodal images and multiclass estimation in future developments.
    No preview · Article · Oct 2015 · Medical Physics
  • F. Lamare · H. Fayad · P. Fernandez · D. Visvikis
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    ABSTRACT: Purpose: Despite multiple methodologies already proposed to correct respiratory motion in the whole PET imaging field of view (FOV), such approaches have not found wide acceptance in clinical routine. An alternative can be the local respiratory motion correction (LRMC) of data corresponding to a given volume of interest (VOI: organ or tumor). Advantages of LRMC include the use of a simple motion model, faster execution times, and organ specific motion correction. The purpose of this study was to evaluate the performance of LMRC using various motion models for oncology (lung lesion) applications.
    No preview · Article · Oct 2015 · Medical Physics
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    ABSTRACT: Purpose The aim of this retrospective study was to determine if some features of baseline 18F-FDG PET images, including volume and heterogeneity, reflect clinical, histological or immunohistochemical characteristics in patients with stage II or III breast cancer (BC). Methods Included in the present retrospective analysis were 171 prospectively recruited patients with stage II/III BC treated consecutively at Saint-Louis hospital. Primary tumour volumes were semiautomatically delineated on pretreatment 18F-FDG PET images. The parameters extracted included SUVmax, SUVmean, metabolically active tumour volume (MATV), total lesion glycolysis (TLG) and heterogeneity quantified using the area under the curve of the cumulative histogram and textural features. Associations between clinical/histopathological characteristics and 18F-FDG PET features were assessed using one-way analysis of variance. Areas under the ROC curves (AUC) were used to quantify the discriminative power of the features significantly associated with clinical/histopathological characteristics. Results T3 tumours (>5 cm) exhibited higher textural heterogeneity in 18F-FDG uptake than T2 tumours (AUC
    No preview · Article · Jul 2015 · European Journal of Nuclear Medicine
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    ABSTRACT: Objective: This study investigated whether 18FDG-PET/CT performed at baseline and during neoadjuvant chemotherapy (NAC) is able to early depict estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+/HER2-) breast cancer patients with poor clinical outcome. Materials and Methods: NAC consisted in 4 cycles of epirubicin + cyclophosphamide, followed by 4 cycles of docetaxel. 18FDG-PET/CT was performed at baseline and after two cycles. At completion of NAC, all patients had breast surgery with lymph node dissection. We examined the association between distant metastases detected on baseline 18FDG-PET/CT and patients’ outcome. We assessed the impact of SUVmax and total lesion glycolysis (TLG) at each PET, on event-free survival (EFS). The impact of tumor characteristics on EFS was also assessed. Results: Ninety-eight consecutive patients with ER+/HER2- breast cancer were included. 18FDG-PET/CT revealed distant metastases in 14 patients (14%). Overall survival was significantly shorter in these patients than in the 84 patients classified M0 at baseline PET/CT (P < 0.001). Impact of FDG-PET parameters on event-free survival in M0 patients: 12 patients had tumor SUVmax >10 and a 3-year EFS of 49% (vs 92% in patients with SUVmax ≤ 10). A low change in SUVmax between PET1 and PET2 was also associated with recurrence (P = 0.033), as was a low change in TLG (P < 0.001). Except for progesterone receptor expression, baseline tumor characteristics (histology, grade) were poorly correlated to the risk of relapse. Again, the extent of pathologic response at completion of NAC (partial/complete vs. nonresponders) was not predictive of EFS. Conclusion: Baseline tumor 18FDG uptake and modifications after 2 cycles of neoadjuvant chemotherapy are prognostic of outcome in patients with ER+/HER2- breast cancer.
    Full-text · Conference Paper · Jun 2015
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    ABSTRACT: Objectives : To investigate FDG-PET/CT parameters that are best correlated with pathological complete response (pCR) in HER2+ and triple-negative breast cancer (TNBC) or partial/complete response in ER+/HER2- breast cancer. Methods : Retrospective analysis of PET-derived parameters data acquired in consecutive patients treated by neoadjuvant chemotherapy (NAC). Five parameters were tested: SUVmax, SUVpeak, SUVmean, metabolically active tumor volume (MATV) and total lesion glycolysis (TLG). Absolute values at PET1 (before NAC), at PET2 (after 2 cycles), and the variation (Δ) were measured in the primary tumor and also in axillary lymph nodes. Correlations with pathologic response (Wilcoxon rank-sum test) and the predictive power assessed (AUC based on ROC analysis) were examined for PET parameters measured over the primary tumor and an additional analysis was performed with measures over lymph nodes. Results : One hundred sixty nine consecutive patients were included. pCR was more frequent in HER2+ (16/33; 48.5%) and TNBC (20/54; 37%) than in ER+/HER2- (4/82; 4.9%) (P<0.001). Among ER+/HER2- patients, 33 had partial response. In TNBC, best association with pCR was obtained with ΔSUVmax (AUC=0.86) or ΔTLG (AUC=0.88). In HER2+ phenotype, the absolute SUVmax (or SUVpeak) values at PET2 (AUC=0.93 for each) were better correlated with pCR than ΔSUVmax (AUC=0.78; p=0.11) or ΔTLG (AUC=0.62; p=0.005)”. As regards ER+/HER2-, ΔSUVmax or ΔTLG (AUC=0.75) were the parameters best correlated with partial/complete response. Baseline SUVmax value was higher in lymph nodes than in the primary tumor in 31 patients. Overall results were not substantially different when PET parameters considered the site with highest FDG uptake. Conclusions : Quantitative indices of tumor glucose utilization that are best correlated with pathologic response vary by phenotype: ΔSUVmax or ΔTLG are most adequate for TNBC and ER+/HER2- and absolute SUVmax value after two cycles for HER2+ breast cancer.
    Full-text · Conference Paper · Jun 2015
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    ABSTRACT: Several quantitative features can be extracted from 18F-FDG PET images, such as standardized uptake values (SUVs), metabolic tumor volume (MTV), shape characterization (SC) or intra-tumor radiotracer heterogeneity quantification (HQ). Some of these features calculated from baseline 18F-FDG PET images have shown a prognostic and predictive clinical value. It has been hypothesized that these features highlight underlying tumor patho-physiological processes at smaller scales. The objective of this study was to investigate the ability of recovering alterations of signaling pathways from FDG PET image-derived features. 52 patients were prospectively recruited from two medical centers (Brest and Poitiers). All patients underwent an FDG PET scan for staging and biopsies of both healthy and primary tumor tissues. Biopsies went through a transcriptomic analysis performed in four spates on 4×44k chips (Agilent™). Primary tumors were delineated in the PET images using the Fuzzy Locally Adaptive Bayesian algorithm and characterized using 10 features including SUVs, SC and HQ. A module network algorithm followed by functional annotation was exploited in order to link PET features with signaling pathways alterations. Several PET-derived features were found to discriminate differentially expressed genes between tumor and healthy tissue (fold-change >2, p<0.01) into 30 co-regulated groups (p<0.05). Functional annotations applied to these groups of genes highlighted associations with well-known pathways involved in cancer processes, such as cell proliferation and apoptosis, as well as with more specific ones such as unsaturated fatty acids. Quantitative features extracted from baseline 18F-FDG PET images usually exploited only for diagnosis and staging, were identified in this work as being related to specific altered pathways and may show promise as tools for personalizing treatment decisions.
    No preview · Article · Jun 2015 · Medical Physics
  • L Fanchon · A Apte · O Dzyubak · G Mageras · E Yorke · D Visvikis · M Hatt · S Solomon · A Kirov
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    ABSTRACT: PET/CT guidance is used for biopsies of metabolically active lesions, which are not well seen on CT alone or to target the metabolically active tissue in tumor ablations. It has also been shown that PET/CT guided biopsies provide an opportunity to verify the location of the lesion border at the place of needle insertion. However the error in needle placement with respect to the metabolically active region may be affected by motion between the PET/CT scan performed at the start of the procedure and the CT scan performed with the needle in place and this error has not been previously quantified. Specimens from 31 PET/CT guided biopsies were investigated and correlated to the intraoperative PET scan under an IRB approved HIPAA compliant protocol. For 4 of the cases in which larger motion was suspected a second PET scan was obtained with the needle in place. The CT and the PET images obtained before and after the needle insertion were used to calculate the displacement of the voxels along the needle path. CTpost was registered to CTpre using a free form deformable registration and then fused with PETpre. The shifts between the PET image contours (42% of SUVmax) for PETpre and PETpost were obtained at the needle position. For these extreme cases the displacement of the CT voxels along the needle path ranged from 2.9 to 8 mm with a mean of 5 mm. The shift of the PET image segmentation contours (42% of SUVmax) at the needle position ranged from 2.3 to 7 mm between the two scans. Evaluation of the mis-registration between the CT with the needle in place and the pre-biopsy PET can be obtained using deformable registration of the respective CT scans and can be used to indicate the need of a second PET in real-time. This work is supported in part by a grant from Biospace Lab, S.A.
    No preview · Article · Jun 2015 · Medical Physics

  • No preview · Article · May 2015 · Medecine Nucleaire
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    Full-text · Article · May 2015

  • No preview · Article · May 2015 · Medecine Nucleaire
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    Florian Monnier · Hadi Fayad · Julien Bert · Holger Schmidt · Dimitris Visvikis

    Full-text · Article · May 2015

  • No preview · Article · May 2015 · Medecine Nucleaire

  • No preview · Article · May 2015 · Medecine Nucleaire

  • No preview · Article · May 2015 · Medecine Nucleaire
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    ABSTRACT: Purpose To investigate parameters based on fluorine 18 fluorodeoxyglucose (FDG) positron emission tomographic (PET) imaging that are best correlated with pathologic complete response (PCR) in human epidermal growth factor receptor type 2 (HER2)-positive cancer and triple-negative breast cancer (TNBC) and with partial or complete response in ER-positive/HER2-negative breast cancer. Materials and Methods This study was approved by institutional review board with waivers of informed written consent and included consecutive patients treated by neoadjuvant chemotherapy. Five PET examination-derived parameters were tested: standard uptake value (SUV) maximum (SUVmax), peak (SUVpeak), and mean (SUVmean), metabolically active tumor volume, and total lesion glycolysis (TLG). Absolute values at baseline PET, at PET imaging after two cycles of chemotherapy, and variation (ie, change) were measured. Correlations with pathologic response (Wilcoxon rank-sum test) and predictive power assessed (area under the curve [AUC] on the basis of receiver operating characteristic analysis) were examined. Results Included were 169 consecutive patients (mean age, 50 years). PCR was more frequent in HER2-positive tumors (16 of 33 patients [48.5%]) and TNBCs (20 of 54 patients [37%]) than in ER positive/HER2-negative tumors (four of 82 [4.9%]) (P < .001). Among patients with ER-positive/HER2-negative cancers, 33 patients had partial response. In TNBC, best association with PCR was obtained with change in SUVmax (AUC, 0.86) or change in TLG (AUC, 0.88). In HER2-positive phenotype, absolute SUVmax (or SUVpeak) values at PET imaging after two cycles of chemotherapy (AUC for each cycle, 0.93) were better correlated with PCR than change in SUVmax (AUC, 0.78; P = .11) or change in TLG (AUC, 0.62; P = .005). Regarding ER-positive/HER2-negative cancers, change in SUVmax or change in TLG (AUC, 0.75) were parameters best correlated with partial or complete response. Baseline SUVmax was higher in lymph nodes than in primary tumor in 31 patients. Findings were similar considering the site with highest FDG uptake. Conclusion Quantitative indexes of tumor glucose use that are best correlated with pathologic response vary by phenotype: change in SUVmax or TLG are most adequate for TNBCs and ER-positive/ HER2-negative cancers and absolute SUVmax after two cycles of chemotherapy for HER2-positive breast cancers. (©) RSNA, 2015.
    No preview · Article · Apr 2015 · Radiology
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    Hadi Fayad · Holger Schmidt · Christian Würslin · Dimitris Visvikis
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    ABSTRACT: Simultaneous positron emission tomography (PET) and magnetic resonance imaging (MRI) is a promising new technique allowing the fusion of functional (PET) and anatomical/functional (MR) information. In the thoracic-abdominal regions, respiratory motion is a major challenge leading to reduced quantitative and qualitative image accuracy. Correction methodologies include the use of gated frames which lead to low signal to noise ratio (SNR) considering the associated low statistics. More advanced correction approaches, previously developed in PET/Computed Tomography (CT) imaging, consist on either registering all the reconstructed gated frames to the reference one or incorporating motion parameters into the iterative reconstruction process to produce a single motion-compensated PET image. The goal of this work was to compare these two, previously implemented in PET/CT, correction approaches within the context of PET/MR motion correction for oncology applications using clinical 4D-PET/MR acquisitions. Two different correction approaches were evaluated, comparing the incorporation of elastic transformations extracted from four dimensional (4D) MRI datasets during PET list-mode image reconstruction to a post-reconstruction image based approach. Eleven patient datasets acquired on the SIEMENS mMR PET/MR system were used. T1-weighted 4D-MR images were registered to the end expiration image using a non-rigid B-spline registration algorithm to derive deformation matrices (DMs) accounting for respiratory motion. The derived matrices were subsequently incorporated within a PET image reconstruction of the original emission list-mode data (reconstruction space (RS) method). The corrected images were compared with those produced by applying the DMs in the image space (IS method) followed by summing the realigned gated frames, as well as with uncorrected motion averaged images. Both correction techniques lead to significant improvement in accounting for respiratory motion artifacts when compared to uncorrected motion average images. These improvements include SNR (mean increase of 28.0% and 24.2% for the RS and IS methods respectively), the lesion size (reduction of 60.4% and 47.9% respectively), lesion contrast (increase of 70.1% and 57.2%) and lesion position (changes of 60.9% and 46.7%). Our results demonstrate significant respiratory motion compensation using both methods, with superior results from a 4D-PET RS approach. Copyright © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.
    Full-text · Article · Apr 2015 · Journal of Nuclear Medicine
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    ABSTRACT: This study investigated whether (18)FDG-PET/CT performed at baseline and during neoadjuvant chemotherapy (NAC) is able to early depict estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+/HER2-) breast cancer patients with poor clinical outcome. NAC regimen consisted in 4 cycles of epirubicin plus cyclophosphamide, followed by 4 courses of docetaxel. The patients had (18)FDG-PET/CT at baseline and after two cycles of chemotherapy. After completion of NAC, all patients had breast surgery with axillary lymph nodes dissection. We assessed the impact of two PET parameters, "maximum" standardized uptake values (SUVmax) and total lesion glycolysis (TLG), on event-free survival (EFS). Ninety-eight consecutive patients with ER+/HER2- breast cancer were included. (18)FDG-PET/CT revealed distant metastases in 14 patients (14%). Overall survival was significantly shorter in these patients than in the 84 patients classified M0 at baseline (18)FDG-PET/CT (P < 0.001). In M0-patients, high SUVmax at baseline was associated with shorter EFS (P < 0.001). Twelve patients had tumor SUVmax > 10 and a 3-year EFS of 49% (vs 92% in patients with baseline SUVmax < 10). A low change in SUVmax between PET1 and PET2 was also associated with recurrence (P = 0.033), as was a low change in TLG (P < 0.001). Contrarily to PET-based prediction, the extent of pathological response after completion of NAC (partial/complete vs non-responders) was poorly correlated to the risk of relapse. Baseline tumor (18)FDG uptake and modifications after 2 cycles of neoadjuvant chemotherapy are prognostic of outcome in patients with ER+/HER2- breast cancer. Copyright © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.
    No preview · Article · Apr 2015 · Journal of Nuclear Medicine

Publication Stats

4k Citations
625.70 Total Impact Points

Institutions

  • 2007-2016
    • Unité Inserm U1077
      Caen, Lower Normandy, France
    • The University of Manchester
      • School of Chemical Engineering and Analytical Science
      Manchester, ENG, United Kingdom
  • 2015
    • University of Tuebingen
      • Department of Radiology
      Tübingen, Baden-Württemberg, Germany
  • 2001-2015
    • Université de Bretagne Occidentale
      • UMR S1101 - Laboratoire de Traitement de l'Information Médicale - LATIM
      Brest, Brittany, France
    • King's College London
      • Department of Psychological Medicine
      London, ENG, United Kingdom
  • 2012-2014
    • CHRU de Strasbourg
      Strasburg, Alsace, France
    • Universität Bern
      Berna, Bern, Switzerland
  • 2003-2014
    • French Institute of Health and Medical Research
      Lutetia Parisorum, Île-de-France, France
    • Ontario Institute for Cancer Research
      Toronto, Ontario, Canada
  • 2013
    • Forschungszentrum Jülich
      • Institute of Neurosciences and Medicine (INM)
      Jülich, North Rhine-Westphalia, Germany
    • Aix-Marseille Université
      Marsiglia, Provence-Alpes-Côte d'Azur, France
  • 2011
    • Bergische Universität Wuppertal
      Wuppertal, North Rhine-Westphalia, Germany
  • 2010
    • Johns Hopkins University
      • Department of Radiology
      Baltimore, Maryland, United States
    • Cea Leti
      Grenoble, Rhône-Alpes, France
  • 2009
    • University of Lyon
      Lyons, Rhône-Alpes, France
  • 2000-2004
    • Middlesex Hospital
      मिडलटाउन, Connecticut, United States
    • London Research Institute
      Londinium, England, United Kingdom
  • 2000-2003
    • Middlesex University, UK
      Londinium, England, United Kingdom
  • 1998
    • The Royal Marsden NHS Foundation Trust
      • Joint Department of Physics
      Londinium, England, United Kingdom
  • 1995
    • Institute of Cancer Research
      Londinium, England, United Kingdom