N. Betrouni - Academia.edu (original) (raw)
Papers by N. Betrouni
Abstracts of the 47th Annual Meeting of the SENP (Société Européenne De Neurologie Pédiatrique)
Lasers in Medical Science
IRBM, 2016
Purpose Glioblastoma (GBM) treatment still remains a complex challenge. Among alternatives or adj... more Purpose Glioblastoma (GBM) treatment still remains a complex challenge. Among alternatives or adjuvant therapies, photodynamic therapy (5-ALA PDT) appears to be a promising approach. 5-ALA PDT can be delivered intraoperatively, early after tumour resection, or interstitially according to brain tumour location. A treatment planning system was designed to manage dosimetry issues before PDT delivery. Methods The TPS was developed according to a specific workflow from stereotactic image registration to light fluence rate modelling. Here, we describe a proof of concept of a treatment planning system (TPS) dedicated to interstitial 5-ALA PDT. This tool enables the planning of a whole treatment in surgical stereotactic conditions. Stereotactic registration and dosimetry components are detailed and evaluated. The registration process is compared to a commercial solution (Leksell Gamma Plan®, Elekta®, Sweden) defined as the ground truth and dosimetry model implemented in our TPS and is compared to numerical simulations. Results Registration achieved a sub-millimetric mean relative error that matched the standard MRI resolution. Dosimetry comparison showed a negligible error between analytical and numerical models and enabled a validation of the dosimetry algorithm implemented. Conclusions A treatment planning system was designed to achieve 5-ALA PDT simulations before the patients underwent surgery. Similarly, for radiation therapy, we proposed a system to plan and evaluate the 5-ALA PDT dosimetry for optimizing treatment delivery. Although this system remains to be perfected, this preliminary work aimed to demonstrate the feasibility of planning 5-ALA PDT treatments in stereotactic conditions. Future improvements will mainly focus on the optimization of the treatment delivery, automatic segmentation and GPU-accelerated Monte-Carlo management to take into account GBM tissue heterogeneity.
Journal of Digital Imaging, 2016
For many years, prostate segmentation on MR imagesconcerned only the extraction of the entire gla... more For many years, prostate segmentation on MR imagesconcerned only the extraction of the entire gland. Currently, in the focal treatment era, there is a continuously increasing need for the separation of the different parts of the organ. In this paper, we propose an automatic segmentation method based on the use of T2W images and atlas images to segment the prostate and to isolate the peripheral and transition zones. The algorithm consists of two stages. First, the target image is registered with each zonal atlas image then the segmentation is obtained by the application ofan evidential C-Means clustering. The method was evaluated on a representative and multi-centric images base and yielded mean Dice accuracy values of 0.81, 0.70 and 0.62 for the prostate, the transition zone and peripheral zone respectively.
Annales de Dermatologie et de Vénéréologie, 2015
ABSTRACT Auteur correspondant. Clinique de dermatologie, 1, rue Michel-Polonovski 59037 Lille ced... more ABSTRACT Auteur correspondant. Clinique de dermatologie, 1, rue Michel-Polonovski 59037 Lille cedex, France.
European Urology Supplements, 2011
To assess the value of endorectal magnetic resonance and MR spectroscopic imaging (MRSI), combine... more To assess the value of endorectal magnetic resonance and MR spectroscopic imaging (MRSI), combined with total PSA (tPSA) and free PSA (fPSA), for the detection of prostate cancer (PCa), in the peripheral and the transitional zones, in men with elevated tPSA levels, with or without previous negative biopsies Materials & Methods: We performed endorectal MRI and MRSI in 246 patients (mean follow up: 27.6 months), with elevated tPSA (median, 7.81 ng/ml) with or without previous negative biopsies, followed by TRUS guided biopsy of the prostate (ten cores plus 2 cores in central zone). In case of negative biopsies, we subsequently followed these patients with additional biopsies when persistent rise of tPSA. Before each additional biopsy, patients were submitted to MR spectroscopic imaging. We analyzed MRI and MRSI findings, tPSA, and fPSA and compared them with biopsies and/or histopathology. Gleason score was determined and compared with MRI and MRSI. The likelihood of cancer in each sextant according to MRI and MRSI findings was graded independently on a scale from 1 (benign) to 5 (malignant). Detection accuracy and a multivariate logistic regression analysis were used to determine the most accurate combination to detect prostate cancer according to Auks. results: No statistical difference in tPSA was found between the group of patients with negative histology and the group of patients with PCa (p = 0.551). In the peripheral zone, the risk of having a positive biopsy in the group of patients with a grade 3 spectroscopy was greater than in patients with a grade 1 or 2 spectroscopy with an OR=65.7. Patients with a grade 4 or 5 spectroscopy had the greatest risk of having a positive biopsy with an OR=398.4. The model incorporating MR imaging, MR spectroscopy and fPSA was significantly more accurate in the prediction of prostate cancer (AUC=96.5%) than other models. In the transitional zone the same model was less accurate in the prediction of prostate cancer (AUC=84.5%). Furthermore, we found a significant positive association (p = 0.005) between grade of spectroscopy and Gleason score in patients with PCa, both in the peripheral and in the transitional zone. Conclusions: Endorectal MR spectroscopic imaging plays an important role in the follow up of patients with elevated PSA, with or without previous negative biopsies. It is helpful in the detection and localization of PCa, reduces the number of biopsies and determines the decision-making process during the follow up. The presence of a suspicious lesion in a RMS study (grade 3-4-5) should always be followed and confirmed with repeated biopsies, or TURP if placed in the central gland. The absence of lesions in patients with repeated negative biopsies should take us to stop biopsying the patient. In patients with a negative MRSI, the presence of a high Gleason lesion is very unlikely, and therefore, these patients would be candidates for follow up.
Progrès en Urologie, 2013
Annales de Dermatologie et de Vénéréologie, 2015
ABSTRACT Auteur correspondant. Clinique de dermatologie, 1, rue Michel-Polonovski, 59037 Lille ce... more ABSTRACT Auteur correspondant. Clinique de dermatologie, 1, rue Michel-Polonovski, 59037 Lille cedex, France.
Journal de Radiologie, 2005
Photodiagnosis and Photodynamic Therapy, 2015
2009 IEEE International Symposium on Biomedical Imaging: From Nano to Macro, 2009
Fractal geometry may be an efficient tool for texture analysis in medical imaging. However its ap... more Fractal geometry may be an efficient tool for texture analysis in medical imaging. However its application is primarily restricted to 2D cases and at the only use of an approximation method of the fractal dimension (FD). Recently, multifractal analysis has showed interesting results in this field. This study focuses on the use of an optimized set of 3D fractal and
Photonic Therapeutics and Diagnostics VI, 2010
ABSTRACT This paper aims to describe the development of a method to monitor laser interstitial th... more ABSTRACT This paper aims to describe the development of a method to monitor laser interstitial thermo therapy by MR images. The method is based on the texture analysis using fractal geometry features of the images to estimate the size of the induced necrosis. The method was validated by comparing the results to macroscopic measurements. It demonstrates the ability to achieve good estimation of the necrosis in ex-vivo experimentations involving pig liver and in vivo experimentations done on tumors grown on Copenhagen rats.
Bulletin du cancer, 2011
Photodynamic therapy (PDT) is an innovative therapeutic modality in urologic oncology. We reviewe... more Photodynamic therapy (PDT) is an innovative therapeutic modality in urologic oncology. We reviewed the current literature on principles and modalities of PDT in urothelial and penile oncology. PDT has been tested for the treatment recurrent superficial bladder tumors and in situ carcinoma. Carcinologic efficacy has been observed with first generation photosensitizer. The lack of selectivity for tumoral cells was responsible of serious adverse events. Development of selective photosensitizers has reduced the importance of side effects. Data concerning PDT for upper urinary tract and urethra carcinoma are still limited. First PDT clinical applications in urothelial oncology have shown some effectiveness at the cost of significant morbidity. The development of selective photosensitizers should help to reduce side effects.
Progrès en urologie : journal de l'Association française d'urologie et de la Société française d'urologie, 2011
Photodynamic therapy (PDT) is an innovative therapeutic modality in urologic oncology. We reviewe... more Photodynamic therapy (PDT) is an innovative therapeutic modality in urologic oncology. We reviewed the current literature on principles and modalities of PDT in prostatic oncology. Focal therapy of prostate cancer is an application field of PDT. Clinical phase II studies are ongoing to determine PDT efficacy and safety in this indication. PDT as salvage treatment after prostatic radiotherapy has been tested. Carcinologic results were promising but important side effects were reported. Individual dosimetric planification is necessary to avoid this toxicity. PDT first clinical experience for prostate cancer has showed its technical feasibility. Several research ways are currently in study to improve carcinologic efficacy and to limit potential side effects.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2008
A new automatic method for tumor volume segmentation on PET images has been developed. The method... more A new automatic method for tumor volume segmentation on PET images has been developed. The method introduced in this paper is based on previous works in MRA segmentation and involves both fuzzy set and possibility theories. Visual results prove the method efficiency which is confirmed by obtained Jaccard index.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2007
In this paper, we introduce an approach for selective segmentation of vascular structure which ha... more In this paper, we introduce an approach for selective segmentation of vascular structure which has been applied for intracranial vessels. Based on MIP and fuzzy set principles, this approach brings good results while segmentation is achieved rapidly. The added value of this approach is a minimal user interaction and the taking into account of the volume partial effect. This approach has been evaluated following different experiment: phantom tests, clinical data, and methods comparison.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2006
The goal of 3D conformal radiotherapy (CRT) is to conform the high dose region to the target volu... more The goal of 3D conformal radiotherapy (CRT) is to conform the high dose region to the target volume while sparing surrounding normal tissue. Knowledge about the mobility of organs relative to the bony anatomy and to the reference position is of great importance when daily positioning patient. In this work we present a method to monitor patient setup during CRT of prostate cancer. The method is based on ultrasound tracking and matching with planning modality.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2004
This paper describes a method to register ultrasound images (US) to pre-treatment images. The aim... more This paper describes a method to register ultrasound images (US) to pre-treatment images. The aim of the work is the information transfer between the pre-treatment imaging modality (MR or CT) and the intra-treatment imaging (US). Ultrasound images are spatially tracked by a stereo-vision system and the prostate boundaries are automatically extracted using a method that combines morphological and adaptive speckle suppression and a priori knowledge. MR/CT images are merged to construct a volume of pelvis using fuzzy logic algorithm and an MPR virtual slice corresponding to the orientation of the US image is generated from the volume. The prostate is segmented from the slice by a model-based method and rigidly registered by ICP algorithm to the US contour. Preliminary experiences gave satisfactory results with short computing time.
Lecture Notes in Computer Science, 2003
This paper deals with a new approach of registration in multimodal imaging. Modalities involved a... more This paper deals with a new approach of registration in multimodal imaging. Modalities involved are Digital Subtracted Angiography (DSA, 2D) and Magnetic Resonance Angiography (MRA, 3D). Our approach is an hybrid one, mixing feature and intensity ...
Computers in Biology and Medicine, 2014
Computer technology is widely used for the multimodal image analysis of the prostate gland. Sever... more Computer technology is widely used for the multimodal image analysis of the prostate gland. Several techniques have been developed, most of which incorporate the a priori knowledge extracted from organ features. Knowledge extraction and modelling are multi-step tasks. Here, we review these steps and classify the modelling according to the data analysis methods employed and the features used. We conclude with a survey of some clinical applications where these techniques are employed.
Abstracts of the 47th Annual Meeting of the SENP (Société Européenne De Neurologie Pédiatrique)
Lasers in Medical Science
IRBM, 2016
Purpose Glioblastoma (GBM) treatment still remains a complex challenge. Among alternatives or adj... more Purpose Glioblastoma (GBM) treatment still remains a complex challenge. Among alternatives or adjuvant therapies, photodynamic therapy (5-ALA PDT) appears to be a promising approach. 5-ALA PDT can be delivered intraoperatively, early after tumour resection, or interstitially according to brain tumour location. A treatment planning system was designed to manage dosimetry issues before PDT delivery. Methods The TPS was developed according to a specific workflow from stereotactic image registration to light fluence rate modelling. Here, we describe a proof of concept of a treatment planning system (TPS) dedicated to interstitial 5-ALA PDT. This tool enables the planning of a whole treatment in surgical stereotactic conditions. Stereotactic registration and dosimetry components are detailed and evaluated. The registration process is compared to a commercial solution (Leksell Gamma Plan®, Elekta®, Sweden) defined as the ground truth and dosimetry model implemented in our TPS and is compared to numerical simulations. Results Registration achieved a sub-millimetric mean relative error that matched the standard MRI resolution. Dosimetry comparison showed a negligible error between analytical and numerical models and enabled a validation of the dosimetry algorithm implemented. Conclusions A treatment planning system was designed to achieve 5-ALA PDT simulations before the patients underwent surgery. Similarly, for radiation therapy, we proposed a system to plan and evaluate the 5-ALA PDT dosimetry for optimizing treatment delivery. Although this system remains to be perfected, this preliminary work aimed to demonstrate the feasibility of planning 5-ALA PDT treatments in stereotactic conditions. Future improvements will mainly focus on the optimization of the treatment delivery, automatic segmentation and GPU-accelerated Monte-Carlo management to take into account GBM tissue heterogeneity.
Journal of Digital Imaging, 2016
For many years, prostate segmentation on MR imagesconcerned only the extraction of the entire gla... more For many years, prostate segmentation on MR imagesconcerned only the extraction of the entire gland. Currently, in the focal treatment era, there is a continuously increasing need for the separation of the different parts of the organ. In this paper, we propose an automatic segmentation method based on the use of T2W images and atlas images to segment the prostate and to isolate the peripheral and transition zones. The algorithm consists of two stages. First, the target image is registered with each zonal atlas image then the segmentation is obtained by the application ofan evidential C-Means clustering. The method was evaluated on a representative and multi-centric images base and yielded mean Dice accuracy values of 0.81, 0.70 and 0.62 for the prostate, the transition zone and peripheral zone respectively.
Annales de Dermatologie et de Vénéréologie, 2015
ABSTRACT Auteur correspondant. Clinique de dermatologie, 1, rue Michel-Polonovski 59037 Lille ced... more ABSTRACT Auteur correspondant. Clinique de dermatologie, 1, rue Michel-Polonovski 59037 Lille cedex, France.
European Urology Supplements, 2011
To assess the value of endorectal magnetic resonance and MR spectroscopic imaging (MRSI), combine... more To assess the value of endorectal magnetic resonance and MR spectroscopic imaging (MRSI), combined with total PSA (tPSA) and free PSA (fPSA), for the detection of prostate cancer (PCa), in the peripheral and the transitional zones, in men with elevated tPSA levels, with or without previous negative biopsies Materials & Methods: We performed endorectal MRI and MRSI in 246 patients (mean follow up: 27.6 months), with elevated tPSA (median, 7.81 ng/ml) with or without previous negative biopsies, followed by TRUS guided biopsy of the prostate (ten cores plus 2 cores in central zone). In case of negative biopsies, we subsequently followed these patients with additional biopsies when persistent rise of tPSA. Before each additional biopsy, patients were submitted to MR spectroscopic imaging. We analyzed MRI and MRSI findings, tPSA, and fPSA and compared them with biopsies and/or histopathology. Gleason score was determined and compared with MRI and MRSI. The likelihood of cancer in each sextant according to MRI and MRSI findings was graded independently on a scale from 1 (benign) to 5 (malignant). Detection accuracy and a multivariate logistic regression analysis were used to determine the most accurate combination to detect prostate cancer according to Auks. results: No statistical difference in tPSA was found between the group of patients with negative histology and the group of patients with PCa (p = 0.551). In the peripheral zone, the risk of having a positive biopsy in the group of patients with a grade 3 spectroscopy was greater than in patients with a grade 1 or 2 spectroscopy with an OR=65.7. Patients with a grade 4 or 5 spectroscopy had the greatest risk of having a positive biopsy with an OR=398.4. The model incorporating MR imaging, MR spectroscopy and fPSA was significantly more accurate in the prediction of prostate cancer (AUC=96.5%) than other models. In the transitional zone the same model was less accurate in the prediction of prostate cancer (AUC=84.5%). Furthermore, we found a significant positive association (p = 0.005) between grade of spectroscopy and Gleason score in patients with PCa, both in the peripheral and in the transitional zone. Conclusions: Endorectal MR spectroscopic imaging plays an important role in the follow up of patients with elevated PSA, with or without previous negative biopsies. It is helpful in the detection and localization of PCa, reduces the number of biopsies and determines the decision-making process during the follow up. The presence of a suspicious lesion in a RMS study (grade 3-4-5) should always be followed and confirmed with repeated biopsies, or TURP if placed in the central gland. The absence of lesions in patients with repeated negative biopsies should take us to stop biopsying the patient. In patients with a negative MRSI, the presence of a high Gleason lesion is very unlikely, and therefore, these patients would be candidates for follow up.
Progrès en Urologie, 2013
Annales de Dermatologie et de Vénéréologie, 2015
ABSTRACT Auteur correspondant. Clinique de dermatologie, 1, rue Michel-Polonovski, 59037 Lille ce... more ABSTRACT Auteur correspondant. Clinique de dermatologie, 1, rue Michel-Polonovski, 59037 Lille cedex, France.
Journal de Radiologie, 2005
Photodiagnosis and Photodynamic Therapy, 2015
2009 IEEE International Symposium on Biomedical Imaging: From Nano to Macro, 2009
Fractal geometry may be an efficient tool for texture analysis in medical imaging. However its ap... more Fractal geometry may be an efficient tool for texture analysis in medical imaging. However its application is primarily restricted to 2D cases and at the only use of an approximation method of the fractal dimension (FD). Recently, multifractal analysis has showed interesting results in this field. This study focuses on the use of an optimized set of 3D fractal and
Photonic Therapeutics and Diagnostics VI, 2010
ABSTRACT This paper aims to describe the development of a method to monitor laser interstitial th... more ABSTRACT This paper aims to describe the development of a method to monitor laser interstitial thermo therapy by MR images. The method is based on the texture analysis using fractal geometry features of the images to estimate the size of the induced necrosis. The method was validated by comparing the results to macroscopic measurements. It demonstrates the ability to achieve good estimation of the necrosis in ex-vivo experimentations involving pig liver and in vivo experimentations done on tumors grown on Copenhagen rats.
Bulletin du cancer, 2011
Photodynamic therapy (PDT) is an innovative therapeutic modality in urologic oncology. We reviewe... more Photodynamic therapy (PDT) is an innovative therapeutic modality in urologic oncology. We reviewed the current literature on principles and modalities of PDT in urothelial and penile oncology. PDT has been tested for the treatment recurrent superficial bladder tumors and in situ carcinoma. Carcinologic efficacy has been observed with first generation photosensitizer. The lack of selectivity for tumoral cells was responsible of serious adverse events. Development of selective photosensitizers has reduced the importance of side effects. Data concerning PDT for upper urinary tract and urethra carcinoma are still limited. First PDT clinical applications in urothelial oncology have shown some effectiveness at the cost of significant morbidity. The development of selective photosensitizers should help to reduce side effects.
Progrès en urologie : journal de l'Association française d'urologie et de la Société française d'urologie, 2011
Photodynamic therapy (PDT) is an innovative therapeutic modality in urologic oncology. We reviewe... more Photodynamic therapy (PDT) is an innovative therapeutic modality in urologic oncology. We reviewed the current literature on principles and modalities of PDT in prostatic oncology. Focal therapy of prostate cancer is an application field of PDT. Clinical phase II studies are ongoing to determine PDT efficacy and safety in this indication. PDT as salvage treatment after prostatic radiotherapy has been tested. Carcinologic results were promising but important side effects were reported. Individual dosimetric planification is necessary to avoid this toxicity. PDT first clinical experience for prostate cancer has showed its technical feasibility. Several research ways are currently in study to improve carcinologic efficacy and to limit potential side effects.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2008
A new automatic method for tumor volume segmentation on PET images has been developed. The method... more A new automatic method for tumor volume segmentation on PET images has been developed. The method introduced in this paper is based on previous works in MRA segmentation and involves both fuzzy set and possibility theories. Visual results prove the method efficiency which is confirmed by obtained Jaccard index.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2007
In this paper, we introduce an approach for selective segmentation of vascular structure which ha... more In this paper, we introduce an approach for selective segmentation of vascular structure which has been applied for intracranial vessels. Based on MIP and fuzzy set principles, this approach brings good results while segmentation is achieved rapidly. The added value of this approach is a minimal user interaction and the taking into account of the volume partial effect. This approach has been evaluated following different experiment: phantom tests, clinical data, and methods comparison.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2006
The goal of 3D conformal radiotherapy (CRT) is to conform the high dose region to the target volu... more The goal of 3D conformal radiotherapy (CRT) is to conform the high dose region to the target volume while sparing surrounding normal tissue. Knowledge about the mobility of organs relative to the bony anatomy and to the reference position is of great importance when daily positioning patient. In this work we present a method to monitor patient setup during CRT of prostate cancer. The method is based on ultrasound tracking and matching with planning modality.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2004
This paper describes a method to register ultrasound images (US) to pre-treatment images. The aim... more This paper describes a method to register ultrasound images (US) to pre-treatment images. The aim of the work is the information transfer between the pre-treatment imaging modality (MR or CT) and the intra-treatment imaging (US). Ultrasound images are spatially tracked by a stereo-vision system and the prostate boundaries are automatically extracted using a method that combines morphological and adaptive speckle suppression and a priori knowledge. MR/CT images are merged to construct a volume of pelvis using fuzzy logic algorithm and an MPR virtual slice corresponding to the orientation of the US image is generated from the volume. The prostate is segmented from the slice by a model-based method and rigidly registered by ICP algorithm to the US contour. Preliminary experiences gave satisfactory results with short computing time.
Lecture Notes in Computer Science, 2003
This paper deals with a new approach of registration in multimodal imaging. Modalities involved a... more This paper deals with a new approach of registration in multimodal imaging. Modalities involved are Digital Subtracted Angiography (DSA, 2D) and Magnetic Resonance Angiography (MRA, 3D). Our approach is an hybrid one, mixing feature and intensity ...
Computers in Biology and Medicine, 2014
Computer technology is widely used for the multimodal image analysis of the prostate gland. Sever... more Computer technology is widely used for the multimodal image analysis of the prostate gland. Several techniques have been developed, most of which incorporate the a priori knowledge extracted from organ features. Knowledge extraction and modelling are multi-step tasks. Here, we review these steps and classify the modelling according to the data analysis methods employed and the features used. We conclude with a survey of some clinical applications where these techniques are employed.