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Papers by Roberto Franchini

Aging Clinical and Experimental Research

Background Accurate estimation of the imminent fragility fracture risk currently represents a cha... more Background Accurate estimation of the imminent fragility fracture risk currently represents a challenging task. The novel Fragility Score (FS) parameter, obtained during a Radiofrequency Echographic Multi Spectrometry (REMS) scan of lumbar or femoral regions, has been developed for the non-ionizing estimation of skeletal fragility. Aims The aim of this study was to assess the performance of FS in the early identification of patients at risk for incident fragility fractures with respect to bone mineral density (BMD) measurements. Methods Data from 1989 Caucasians of both genders were analysed and the incidence of fractures was assessed during a follow-up period up to 5 years. The diagnostic performance of FS to discriminate between patients with and without incident fragility fracture in comparison to that of the BMD T-scores measured by both Dual X-ray Absorptiometry (DXA) and REMS was assessed through ROC analysis. Results Concerning the prediction of generic osteoporotic fractures...

IEEE Transactions on Nanotechnology, 2017

Aim of this work was to perform simulated measurements of the magnetic behavior of a novel class ... more Aim of this work was to perform simulated measurements of the magnetic behavior of a novel class of bimodal nanosized contrast agents (CAs), made of a silica core covered by smaller superparamagnetic nanoparticles (NPs) and designed to be detected through both ultrasound and magnetic resonance imaging (MRI), in order to compare their performance in terms of MRI signal enhancement with that of the superparamagnetic NPs alone. The considered bimodal nanocomposites consisted of 330-nm silica nanospheres covered by either superparamagnetic iron oxide NPs or dumbbell-like FePt-IO nanocrystals. We simulated the MRI signal generated by each of the considered CAs during a brain venography in standard clinical conditions. Quantitative assessments of signal enhancement were carried out as a function of the main model parameters. The performed numerical simulations showed that the magnetic response of the novel nanocomposites was similar or better compared to that of the superparamagnetic NPs alone for echo times longer than 20 ms, leading to an easier detection of smaller vessels. Obtained results suggest that the bimodal NPs have an exciting potential for the development of innovative clinical protocols for multimodal imaging, combining quantitative measurements of cerebral blood flow and targeted molecular imaging of specific diseases.

Ultrasound in Medicine & Biology, 2016

The aim of this paper was to investigate the clinical feasibility and the accuracy in femoral nec... more The aim of this paper was to investigate the clinical feasibility and the accuracy in femoral neck densitometry of the Osteoporosis Score (O.S.), an ultrasound (US) parameter for osteoporosis diagnosis that has been recently introduced for lumbar spine applications. A total of 377 female patients (aged 61-70 y) underwent both a femoral dual X-ray absorptiometry (DXA) and an echographic scan of the proximal femur. Recruited patients were subdivided into a reference database used for ultrasound spectral model construction and a study population for repeatability assessments and accuracy evaluations. Echographic images and radiofrequency signals were analyzed through a fully automatic algorithm that performed a series of combined spectral and statistical analyses, providing as a final output the O.S. value of the femoral neck. Assuming DXA as a gold standard reference, the accuracy of O.S.-based diagnoses resulted 94.7%, with k 5 0.898 (p , 0.0001). Significant correlations were also found between O.S.-estimated bone mineral density and corresponding DXA values, with r 2 up to 0.79 and root mean square error 5 5.9-7.4%. The reported accuracy levels, combined with the proven ease of use and very good measurement repeatability, provide the adopted method with a potential for clinical routine application in osteoporosis diagnosis.

Annals of the Rheumatic Diseases, 2013

In recent years, intensive investigations have been undertaken to develop nanoparticle-based canc... more In recent years, intensive investigations have been undertaken to develop nanoparticle-based cancer targeting agents for various imaging modalities, including ultrasound. Thus, diagnostic paradigms are needed to correctly detect the presence of nanoparticles (NPs) in the anatomic districts. Furthermore, it would be desirable to have algorithms for the automatic recognition of areas where NPs are localized. In this work an experimental

2011 IEEE SENSORS Proceedings, 2011

In recent years, intensive studies have been conducted on the development of nanosized contrast a... more In recent years, intensive studies have been conducted on the development of nanosized contrast agents (CAs) for multimodal molecular imaging. In this context, we have demonstrated the possibility of realizing a shell of magnetic nanoparticles (NPs) on acoustically-visible silica nanospheres (SiNSs), in order to obtain new dual-mode CAs detectable through both ultrasound (US) and magnetic resonance imaging (MRI). In the

Magnetic Resonance Imaging, 2010

To improve vessel contrast in high-resolution susceptibility-based brain venography, an automatic... more To improve vessel contrast in high-resolution susceptibility-based brain venography, an automatic phase contrast enhancing procedure is proposed, based on a new phase mask filter suitable for maximizing contrast of venous MR signals. The effectiveness of the new approach was assessed both on digital phantoms and on acquired MR human brain images, and then compared with venographic results of phase masking methods in recent literature. The digital phantom consisted of a simulated MR dataset with given signal-to-noise ratios (SNRs), while real human data were collected by scanning healthy volunteers with a 3.0-T MR system and a 3D gradient echo pulse sequence. The new phase mask (NM) was more effective than the conventional mask (CM) both on the digital phantoms and on the acquired MR images. A quantitative comparison based on phantom venograms indicates how this phase enhancement can lead to a significant increase in the contrast-to-noise ratio (CNR) for all considered phase values as well as for all vessel sizes of clinical interest. Likewise, the in vivo brain venograms reveal a better depiction of the smallest venous vessels and the enhancement of many details undetectable in conventional venograms.

Investigative Radiology, 2011

Wolters Kluwer Health may email you for journal alerts and information, but is committed to maint... more Wolters Kluwer Health may email you for journal alerts and information, but is committed to maintaining your privacy and will not share your personal information without your express consent. For more information, please refer to our Privacy Policy. ... Skip Navigation Links Home > Current ...

IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 2011

Current imaging methods for catheter position monitoring during minimally invasive surgery do not... more Current imaging methods for catheter position monitoring during minimally invasive surgery do not provide an effective support to surgeons, often resulting in the choice of more invasive procedures. This study was conducted to demonstrate the feasibility of non-ionizing monitoring of endovascular devices through embedded quantitative ultrasound (QUS) methods, providing catheter self-localization with respect to selected anatomical structures. QUS-based algorithms for real-time automatic tracking of device position were developed and validated on in vitro and ex vivo phantoms. A trans-esophageal ultrasound probe was adapted to simulate an endovascular device equipped with an intravascular ultrasound probe. B-mode images were acquired and processed in real time by means of a new algorithm for accurate measurement of device position. After off-line verification, automatic position calculation was found to be correct in 96% and 94% of computed frames in the in vitro and ex vivo phantoms, respectively. The average errors of distance measurements (bias ± 2SD) in a 41-step 10-cm-long parabolic pathway were 0.76 ± 3.75 mm or 0.52 ± 3.20 mm, depending on algorithm implementations. Our results showed the effectiveness of QUS-based tracking algorithms for real-time automatic calculation and display of endovascular system position. The method, validated for the case of an endoclamp balloon catheter, can be easily extended to most endovascular surgical systems.

IEEE Sensors Journal, 2012

Academic Radiology, 2011

Rationale and Objectives: The aim of this study was to identify the optimal parameter configurati... more Rationale and Objectives: The aim of this study was to identify the optimal parameter configuration of a new algorithm for fully automatic segmentation of hepatic vessels, evaluating its accuracy in view of its use in a computer system for three-dimensional (3D) planning of liver surgery. Materials and Methods: A phantom reproduction of a human liver with vessels up to the fourth subsegment order, corresponding to a minimum diameter of 0.2 mm, was realized through stereolithography, exploiting a 3D model derived from a real human computed tomographic data set. Algorithm parameter configuration was experimentally optimized, and the maximum achievable segmentation accuracy was quantified for both single two-dimensional slices and 3D reconstruction of the vessel network, through an analytic comparison of the automatic segmentation performed on contrast-enhanced computed tomographic phantom images with actual model features. Results: The optimal algorithm configuration resulted in a vessel detection sensitivity of 100% for vessels > 1 mm in diameter, 50% in the range 0.5 to 1 mm, and 14% in the range 0.2 to 0.5 mm. An average area overlap of 94.9% was obtained between automatically and manually segmented vessel sections, with an average difference of 0.06 mm 2. The average values of corresponding false-positive and false-negative ratios were 7.7% and 2.3%, respectively. Conclusions: A robust and accurate algorithm for automatic extraction of the hepatic vessel tree from contrast-enhanced computed tomographic volume images was proposed and experimentally assessed on a liver model, showing unprecedented sensitivity in vessel delineation. This automatic segmentation algorithm is promising for supporting liver surgery planning and for guiding intraoperative resections.

Ultrasound in Medicine & Biology, 2015

We investigated the possible clinical feasibility and accuracy of an innovative ultrasound (US) m... more We investigated the possible clinical feasibility and accuracy of an innovative ultrasound (US) method for diagnosis of osteoporosis of the spine. A total of 342 female patients (aged 51-60 y) underwent spinal dual X-ray absorptiometry and abdominal echographic scanning of the lumbar spine. Recruited patients were subdivided into a reference database used for US spectral model construction and a study population for repeatability and accuracy evaluation. US images and radiofrequency signals were analyzed via a new fully automatic algorithm that performed a series of spectral and statistical analyses, providing a novel diagnostic parameter called the osteoporosis score (O.S.). If dual X-ray absorptiometry is assumed to be the gold standard reference, the accuracy of O.S.-based diagnoses was 91.1%, with k = 0.859 (p < 0.0001). Significant correlations were also found between O.S.-estimated bone mineral densities and corresponding dual X-ray absorptiometry values, with r(2) values up to 0.73 and a root mean square error of 6.3%-9.3%. The results obtained suggest that the proposed method has the potential for future routine application in US-based diagnosis of osteoporosis.

Aging Clinical and Experimental Research

Background Accurate estimation of the imminent fragility fracture risk currently represents a cha... more Background Accurate estimation of the imminent fragility fracture risk currently represents a challenging task. The novel Fragility Score (FS) parameter, obtained during a Radiofrequency Echographic Multi Spectrometry (REMS) scan of lumbar or femoral regions, has been developed for the non-ionizing estimation of skeletal fragility. Aims The aim of this study was to assess the performance of FS in the early identification of patients at risk for incident fragility fractures with respect to bone mineral density (BMD) measurements. Methods Data from 1989 Caucasians of both genders were analysed and the incidence of fractures was assessed during a follow-up period up to 5 years. The diagnostic performance of FS to discriminate between patients with and without incident fragility fracture in comparison to that of the BMD T-scores measured by both Dual X-ray Absorptiometry (DXA) and REMS was assessed through ROC analysis. Results Concerning the prediction of generic osteoporotic fractures...

IEEE Transactions on Nanotechnology, 2017

Aim of this work was to perform simulated measurements of the magnetic behavior of a novel class ... more Aim of this work was to perform simulated measurements of the magnetic behavior of a novel class of bimodal nanosized contrast agents (CAs), made of a silica core covered by smaller superparamagnetic nanoparticles (NPs) and designed to be detected through both ultrasound and magnetic resonance imaging (MRI), in order to compare their performance in terms of MRI signal enhancement with that of the superparamagnetic NPs alone. The considered bimodal nanocomposites consisted of 330-nm silica nanospheres covered by either superparamagnetic iron oxide NPs or dumbbell-like FePt-IO nanocrystals. We simulated the MRI signal generated by each of the considered CAs during a brain venography in standard clinical conditions. Quantitative assessments of signal enhancement were carried out as a function of the main model parameters. The performed numerical simulations showed that the magnetic response of the novel nanocomposites was similar or better compared to that of the superparamagnetic NPs alone for echo times longer than 20 ms, leading to an easier detection of smaller vessels. Obtained results suggest that the bimodal NPs have an exciting potential for the development of innovative clinical protocols for multimodal imaging, combining quantitative measurements of cerebral blood flow and targeted molecular imaging of specific diseases.

Ultrasound in Medicine & Biology, 2016

The aim of this paper was to investigate the clinical feasibility and the accuracy in femoral nec... more The aim of this paper was to investigate the clinical feasibility and the accuracy in femoral neck densitometry of the Osteoporosis Score (O.S.), an ultrasound (US) parameter for osteoporosis diagnosis that has been recently introduced for lumbar spine applications. A total of 377 female patients (aged 61-70 y) underwent both a femoral dual X-ray absorptiometry (DXA) and an echographic scan of the proximal femur. Recruited patients were subdivided into a reference database used for ultrasound spectral model construction and a study population for repeatability assessments and accuracy evaluations. Echographic images and radiofrequency signals were analyzed through a fully automatic algorithm that performed a series of combined spectral and statistical analyses, providing as a final output the O.S. value of the femoral neck. Assuming DXA as a gold standard reference, the accuracy of O.S.-based diagnoses resulted 94.7%, with k 5 0.898 (p , 0.0001). Significant correlations were also found between O.S.-estimated bone mineral density and corresponding DXA values, with r 2 up to 0.79 and root mean square error 5 5.9-7.4%. The reported accuracy levels, combined with the proven ease of use and very good measurement repeatability, provide the adopted method with a potential for clinical routine application in osteoporosis diagnosis.

Annals of the Rheumatic Diseases, 2013

In recent years, intensive investigations have been undertaken to develop nanoparticle-based canc... more In recent years, intensive investigations have been undertaken to develop nanoparticle-based cancer targeting agents for various imaging modalities, including ultrasound. Thus, diagnostic paradigms are needed to correctly detect the presence of nanoparticles (NPs) in the anatomic districts. Furthermore, it would be desirable to have algorithms for the automatic recognition of areas where NPs are localized. In this work an experimental

2011 IEEE SENSORS Proceedings, 2011

In recent years, intensive studies have been conducted on the development of nanosized contrast a... more In recent years, intensive studies have been conducted on the development of nanosized contrast agents (CAs) for multimodal molecular imaging. In this context, we have demonstrated the possibility of realizing a shell of magnetic nanoparticles (NPs) on acoustically-visible silica nanospheres (SiNSs), in order to obtain new dual-mode CAs detectable through both ultrasound (US) and magnetic resonance imaging (MRI). In the

Magnetic Resonance Imaging, 2010

To improve vessel contrast in high-resolution susceptibility-based brain venography, an automatic... more To improve vessel contrast in high-resolution susceptibility-based brain venography, an automatic phase contrast enhancing procedure is proposed, based on a new phase mask filter suitable for maximizing contrast of venous MR signals. The effectiveness of the new approach was assessed both on digital phantoms and on acquired MR human brain images, and then compared with venographic results of phase masking methods in recent literature. The digital phantom consisted of a simulated MR dataset with given signal-to-noise ratios (SNRs), while real human data were collected by scanning healthy volunteers with a 3.0-T MR system and a 3D gradient echo pulse sequence. The new phase mask (NM) was more effective than the conventional mask (CM) both on the digital phantoms and on the acquired MR images. A quantitative comparison based on phantom venograms indicates how this phase enhancement can lead to a significant increase in the contrast-to-noise ratio (CNR) for all considered phase values as well as for all vessel sizes of clinical interest. Likewise, the in vivo brain venograms reveal a better depiction of the smallest venous vessels and the enhancement of many details undetectable in conventional venograms.

Investigative Radiology, 2011

Wolters Kluwer Health may email you for journal alerts and information, but is committed to maint... more Wolters Kluwer Health may email you for journal alerts and information, but is committed to maintaining your privacy and will not share your personal information without your express consent. For more information, please refer to our Privacy Policy. ... Skip Navigation Links Home > Current ...

IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 2011

Current imaging methods for catheter position monitoring during minimally invasive surgery do not... more Current imaging methods for catheter position monitoring during minimally invasive surgery do not provide an effective support to surgeons, often resulting in the choice of more invasive procedures. This study was conducted to demonstrate the feasibility of non-ionizing monitoring of endovascular devices through embedded quantitative ultrasound (QUS) methods, providing catheter self-localization with respect to selected anatomical structures. QUS-based algorithms for real-time automatic tracking of device position were developed and validated on in vitro and ex vivo phantoms. A trans-esophageal ultrasound probe was adapted to simulate an endovascular device equipped with an intravascular ultrasound probe. B-mode images were acquired and processed in real time by means of a new algorithm for accurate measurement of device position. After off-line verification, automatic position calculation was found to be correct in 96% and 94% of computed frames in the in vitro and ex vivo phantoms, respectively. The average errors of distance measurements (bias ± 2SD) in a 41-step 10-cm-long parabolic pathway were 0.76 ± 3.75 mm or 0.52 ± 3.20 mm, depending on algorithm implementations. Our results showed the effectiveness of QUS-based tracking algorithms for real-time automatic calculation and display of endovascular system position. The method, validated for the case of an endoclamp balloon catheter, can be easily extended to most endovascular surgical systems.

IEEE Sensors Journal, 2012

Academic Radiology, 2011

Rationale and Objectives: The aim of this study was to identify the optimal parameter configurati... more Rationale and Objectives: The aim of this study was to identify the optimal parameter configuration of a new algorithm for fully automatic segmentation of hepatic vessels, evaluating its accuracy in view of its use in a computer system for three-dimensional (3D) planning of liver surgery. Materials and Methods: A phantom reproduction of a human liver with vessels up to the fourth subsegment order, corresponding to a minimum diameter of 0.2 mm, was realized through stereolithography, exploiting a 3D model derived from a real human computed tomographic data set. Algorithm parameter configuration was experimentally optimized, and the maximum achievable segmentation accuracy was quantified for both single two-dimensional slices and 3D reconstruction of the vessel network, through an analytic comparison of the automatic segmentation performed on contrast-enhanced computed tomographic phantom images with actual model features. Results: The optimal algorithm configuration resulted in a vessel detection sensitivity of 100% for vessels > 1 mm in diameter, 50% in the range 0.5 to 1 mm, and 14% in the range 0.2 to 0.5 mm. An average area overlap of 94.9% was obtained between automatically and manually segmented vessel sections, with an average difference of 0.06 mm 2. The average values of corresponding false-positive and false-negative ratios were 7.7% and 2.3%, respectively. Conclusions: A robust and accurate algorithm for automatic extraction of the hepatic vessel tree from contrast-enhanced computed tomographic volume images was proposed and experimentally assessed on a liver model, showing unprecedented sensitivity in vessel delineation. This automatic segmentation algorithm is promising for supporting liver surgery planning and for guiding intraoperative resections.

Ultrasound in Medicine & Biology, 2015

We investigated the possible clinical feasibility and accuracy of an innovative ultrasound (US) m... more We investigated the possible clinical feasibility and accuracy of an innovative ultrasound (US) method for diagnosis of osteoporosis of the spine. A total of 342 female patients (aged 51-60 y) underwent spinal dual X-ray absorptiometry and abdominal echographic scanning of the lumbar spine. Recruited patients were subdivided into a reference database used for US spectral model construction and a study population for repeatability and accuracy evaluation. US images and radiofrequency signals were analyzed via a new fully automatic algorithm that performed a series of spectral and statistical analyses, providing a novel diagnostic parameter called the osteoporosis score (O.S.). If dual X-ray absorptiometry is assumed to be the gold standard reference, the accuracy of O.S.-based diagnoses was 91.1%, with k = 0.859 (p < 0.0001). Significant correlations were also found between O.S.-estimated bone mineral densities and corresponding dual X-ray absorptiometry values, with r(2) values up to 0.73 and a root mean square error of 6.3%-9.3%. The results obtained suggest that the proposed method has the potential for future routine application in US-based diagnosis of osteoporosis.