Tomografía fotoacústica y Deep Learning en aplicacionesmédicas

En las últimas décadas, las imágenes fotoacústicas han demostrado su eficacia en el apoyo al diagnóstico de algunas enfermedades, así como en la investigación médica, ya que a través de ellas es posible obtener información del cuerpo humano con características específicas y profundidad de penetración, desde 1 cm hasta 6 cm dependiendo en gran medida del tejido estudiado, además de una buena resolución. Las imágenes fotoacústicas son comparativamente jóvenes y emergentes y prometen mediciones en tiempo real, con procedimientos no invasivos y libres de radiación. Por otro lado, aplicar Deep Learning a imágenes fotoacústicas permite gestionar datos y transformarlos en información útil que genere conocimiento. Estas aplicaciones poseen ventajas únicas que facilitan la aplicación clínica. Se considera que con estas técnicas se pueden proporcionar diagnósticos médicos confiables. Es por eso que el objetivo de este artículo es proporcionar un panorama general de los casos donde se combina el Deep Learning con técnicas fotoacústicas.

In recent decades, photoacoustic imaging has proven its effectiveness in supporting the diagnosis of some diseases as well as in medical research, since through them it is possible to obtain information of the human body with specific characteristics and depth of penetration, from 1 cm to 6 cm depending largely on the tissue studied, in addition to a good resolution. Photoacoustic imaging is comparatively young and emerging and promises real-time measurements, with non-invasive and radiation-free procedures. On the other hand, applying Deep Learning to photoacoustic images allows managing data and transforming them into useful information that generates knowledge. These applications have unique advantages that facilitate clinical application. It may be possible with these techniques to provide reliable medical diagnoses. That is why the aim of this article is to provide an overview of cases combining Deep Learning with photoacoustic techniques.

Efficacy of the photon-induced photoacoustic streaming combined with nano-silver solution on Enterococcus faecalis in root canals / 口腔医学

Objective@#o explore the antibacterial effect of combined use of photon-induced photoacoustic streaming (PIPS) and silver nanoparticles (AgNPs) on Enterococcus faecalis biofilm in root canals.@*Methods@#A total of 36 isolated teeth with single root canal were collected to establish an experimental root canal model of Enterococcus faecalis infection. Samples were randomly divided into six groups and 0.9% NaCl, 2% NaClO, 0.1% AgNPs solutions were used with conventional needle irrigation (CNI) or PIPS for root canals. Colony count method was used to measure the number of Enterococcus faecalis biofilm in root canals before and after treatment, and the percentage of colony count reduction was calculated.@*Results@#The inhibitory effect of Enterococcus faecalis biofilm in all experimental groups was stronger than that in the control group (P<0.05). The decrease amplitude of 0.9% NaCl, 2% NaClO, 0.1% AgNPs assisted with PIPS was greater than that of 0.9% NaCl, 2% NaClO, 0.1% AgNPs assisted with CNI (P<0.05). The decrease in the 0.1% AgNPs assisted with PIPS group was significantly greater than that in the 2% NaClO assisted with PIPS group (P<0.05).@*Conclusion@#PIPS-assisted AgNPs solution washing can significantly improve the effect of clearing Enterococcus faecalis biofilm in root canals.

Gall Bladder Polyps : A Paradigm Shift – Need for Reappraisal of Guidelines

Background : Gall Bladder Polyps are mucosal lesions that project from the Gall Bladder wall into the Gallbladder lumen. They form morphologically distinct lesion/s with internal characteristics different than that of neighboring structures as verified by microscopic examination. About 4-6% are picked up clinically, 2-12% in Cholecystectomy specimens and 4% on Ultrasound. Materias and Methods : A three calendar year retrospective single surgical unit study compromised of 1442 cholecystectomies performed for benign Gall Bladder Disease. The patient were subjected to Ultrasound of abdomen for diagnosis and routine clinic work up. The Gall Bladders Harboring Polyps were examined grossly for site ,number, and microscopy for histological details. Results : In a total number of 40 cases of Gall Bladder Polyp, females outnumbered males. This series spreads over age groups of 3rd decade - 9th decade, most of the patients were seen in 6th decade of life. Youngest patients were 27 years old and oldest one was 85 years old. Incidentally, none of the old patients had evidence of malignancy on histopathology in their Gall Badder Polyp, only 2% were necessitated for a pre-operative diagnosis of Gall Bladder Polyps alone. Rest required it for presence of Gallstones with or without Polyp. None of >10mm size showed any malignant change on histopathological examination. On the Contrary, among the polypoid lesions <10mm size, one polypid lesion (7mm) showed a malignant change (Carcinoma in situ) Conclusion : A predictive model for neoplastic potential of Gall Bladder Polyp may support clinical decision to achieve an ideal therapeutic outcome. Hence a need for reappraisal of management guidelines.

Multimodal imaging and photothermal/chemotherapy in vitro study of peptide-mediated network engineering paclitaxel nanoparticles loaded with metal polyphenols / 中华超声影像学杂志

Objective:To prepare a phase-change lipid nanoparticle modified by tumor homing membrane-penetrating peptide (tLyP-1) and carrying paclitaxel (PTX) engineered by metal polyphenol network (TA-Fe 3+ ), and evaluate the therapeutic effects of tumor targeting, ultrasound/photoacoustic imaging and photothermal combined chemotherapy in vitro. Methods:Phase-change lipid nanoparticles (t-P@TFP) with TA-Fe 3+ engineered PTX mediated by tLyP-1 were prepared by solvent replacement method, thin film hydration method and double emulsification method. Its detection and characterization, in vitro targeting ability, photothermal conversion ability, in vitro photoacoustic and ultrasonic imaging ability, CCK-8 method, cell live and death double staining method and flow cytometry method were used to detect the safety of nanoparticles and the killing effects of different nanoparticles on 4T1 cells. Results:t-P@TFP nanoparticles were successfully prepared. Transmission electron microscopy showed that the nanoparticles were spherical with uniform shape and size, with a particle size of (209.8±1.56)nm and a potential of (-25.9±1.36)mV. Laser confocal scanning microscopy showed that t-P@TFP nanoparticles could gather around 4T1 cells in a targeted manner. It had an efficient photothermal conversion effect, and nanoparticles could quickly become microbubbles after being irradiated by near-infrared laser, which enhanced the in vitro ultrasonic imaging effect; The photoacoustic signal of nanoparticles increased with the increase of concentration. CCK-8 method, double staining of living and dead cells and flow cytometry showed that t-P@TFP combined photothermal chemotherapy had the best anti-tumor effect. Conclusions:t-P@TFP nanoparticles are successfully prepared. The nanoparticles have good targeting ability for photoacoustic and ultrasonic imaging and have good photothermal effect, killing breast cancer cells, which is expected to realize the integration of diagnosis and treatment.

Deep Learning aplicado en imágenes fotoacústicas para la Identificación del cáncer de seno / Deep Learning Applied in Photoacoustic Images for the Identification of Breast Cancer

La Imagen Fotoacústica (PAI por sus siglas en inglés), es una modalidad de imagen híbrida que fusiona la iluminación óptica y la detección por ultrasonido. Debido a que los métodos de imágenes ópticas puras no pueden mantener una alta resolución, la capacidad de lograr imágenes de contraste óptico de alta resolución en tejidos biológicos hace que la fotoacústica (PA por sus siglas en inglés) sea una técnica prometedora para varias aplicaciones de imágenes clínicas. En la actualidad el Aprendizaje Profundo (Deep Learning) tiene el enfoque más reciente en métodos basados en la PAI, donde existe una gran cantidad de aplicaciones en análisis de imágenes, en especial en el área del campo biomédico, como lo es la adquisición, segmentación y reconstrucciones de imágenes de tomografía computarizada. Esta revisión describe las últimas investigaciones en PAI y un análisis sobre las técnicas y métodos basados en Deep Learning, aplicado en diferentes modalidades para el diagnóstico de cáncer de seno(AU)

Photoacoustic Imaging (PAI) is a hybrid imaging modality that combines optical illumination and ultrasound detection. Because pure optical imaging methods cannot maintain high resolution, the ability to achieve high resolution optical contrast images in biological tissues makes Photoacoustic (PA) a promising technique for various clinical imaging applications. At present, Deep Learning has the most recent approach of methods based on PAI where there are a large number of applications in image analysis especially in the area of ​​the biomedical field, such as acquisition, segmentation and reconstructions of computed tomography imaging. This review describes the latest research in PAI and an analysis of the techniques and methods based on Deep Learning applied in different modalities for the diagnosis of breast cancer(AU)

Development and evaluation of topical formulations that contain hydroethanolic extract from Schinus terebinthifolia against HSV-1 infection

Abstract The therapeutic drugs to treat Herpes simplex virus (HSV) infections have toxic side effects and there has been an emergence of drug-resistant strains. Therefore, the search for new treatments for HSV infections is mounting. In the present study, semi-solid formulations containing a crude hydroethanolic extract (CHE) from Schinus terebinthifolia were developed. Skin irritation, cutaneous permeation, and in vivo therapeutic efficacy of the formulations were investigated. Treatment with the ointment formulations did not result in any signs of skin irritation while the emulsions increased the thickness of the epidermis in Swiss mice. The cutaneous permeation test indicated that the CHE incorporated in the formulations permeated through the skin layers and was present in the epidermis and dermis even 3 h after topical application. In vivo antiviral activity in BALB/c mice treated with the CHE ointments was better than those treated with the CHE emulsions and did not significantly differ from an acyclovir-treated group. Taken together, this suggests that the incorporation of CHE in the ointment may be a potential candidate for the alternative topical treatment of herpetic lesions.

Current status and advances in ultrasound-guided thermal ablation for hepatocellular carcinoma / 临床肝胆病杂志

Hepatocellular carcinoma (HCC) is a common malignant tumor in clinical practice, and image-guided thermal ablation is a radical treatment method for early-stage HCC and a method for palliative tumor reduction and combination with systematic therapy for advanced HCC. With the advantages of real-time imaging, accurate guiding, easy operation, portability, low cost, no radiation damage, and high efficiency, ultrasound plays an important role in preoperative planning, intraoperative guiding, postoperative evaluation, and long-term follow-up in thermal ablation for HCC. With the advances in ultrasound and imaging fusion technology and the development of functional imaging technology represented by photoacoustic imaging, ultrasound-guided thermal ablation is at the forefront of precision treatment of HCC, achieving long-lasting development and developing into a more minimally invasive, accurate, safe, and effective diagnostic and therapeutic mode.

Progress of motion artifact correction in photoacoustic microscopy and photoacoustic tomography / 生物医学工程学杂志

Photoacoustic imaging (PAI) is a rapidly developing hybrid biomedical imaging technology, which is capable of providing structural and functional information of biological tissues. Due to inevitable motion of the imaging object, such as respiration, heartbeat or eye rotation, motion artifacts are observed in the reconstructed images, which reduce the imaging resolution and increase the difficulty of obtaining high-quality images. This paper summarizes current methods for correcting and compensating motion artifacts in photoacoustic microscopy (PAM) and photoacoustic tomography (PAT), discusses their advantages and limits and forecasts possible future work.

Research progress of drug delivery system based on black phosphorus in tumor diagnosis and treatment / 中国药科大学学报

@#As a new member of two-dimensional materials, black phosphorus has shown good application prospects in the fields of photoacoustic imaging, photothermal photodynamic therapy, and drug loading due to its excellent characteristics such as good biodegradability, biocompatibility, thickness-dependent tunable direct band-gap, and high surface-to-mass ratio. Because black phosphorus has the characteristics of easy oxidation and degradation, it is coated with relatively stable liposomes or polymeric materials to construct a black phosphorus-based drug delivery system, which shows great potential in tumor treatment and diagnosis and has become a new focus in drug delivery research. In this paper, we introduce the role of black phosphorus in tumor diagnosis and treatment in detail, and summarize the design of black phosphorus-based drug delivery system in recent years as well as its research progress in tumor diagnosis and treatment, in order to provide reference for the research and application of black phosphorus.

Photoacoustic imaging and photoacoustic spectrum analysis in mouse models of cutaneous squamous cell carcinoma / 中华皮肤科杂志

Objective To establish a photoacoustic detection system and data processing methods for skin tumors,and to explore photoacoustic imaging and photoacoustic spectrum in mouse models of cutaneous squamous cell carcinoma (CSCC).Methods A total of 60 healthy specific pathogen-free (SPF) female BALB/C nude mice aged 6-8 weeks were randomly and equally divided into 2 groups to be inoculated with a murine CSCC cell line XL50 and a human CSCC cell line A431 respectively on the right back near the upper limbs,and mouse models of murine CSCC (n =20) and human CSCC (n =20) were successfully established.The 850-nm photoacoustic detection system was applied in the above 2 kinds of mouse models,and photoacoustic imaging and photoacoustic spectrum data were collected.The fitted slope of acoustic power spectrum curves was compared between squamous cell carcinoma tissues and normal skin on the left back of the mouse model.After the photoacoustic detection,tumor tissues and normal skin at the opposite side were excised from the 2 kinds of mouse models,and subjected to histopathological examination.The fitted slope of different tissues was compared by using t test.Results Photoacoustic imaging showed higher photoacoustic signals of hemoglobin in squamous cell carcinoma tissues compared with the normal skin tissues.In the model of murine CSCC,the fitted slope of acoustic power spectrum curve was significantly lower in the tumor tissues (-1.827 ± 0.153 1) than in the normal skin tissues (-1.059 ± 0.117 8,t =3.973,P ＜ 0.001).In the model of human CSCC,the fitted slope of acoustic power spectrum curve was also significantly lower in the tumor tissues (-1.537 ± 0.125 5) than in the normal skin tissues (-0.960 ± 0.259 7,t =2.166,P =0.043).Histopathological examination showed that the number of vessels increased in the tumor tissues compared with the normal skin tissues.Conclusion CSCC tissues are different from normal skin tissues in photoacoustic imaging signals and the fitted slope of acoustic power spectrum,which may lay a foundation for non-invasive photoacoustic diagnosis of CSCC.

Multimodal Composite Iron Oxide Nanoparticles for Biomedical Applications

BACKGROUND: Iron oxide nanoparticles (IONPs) are excellent candidates for biomedical imaging because of unique characteristics like enhanced colloidal stability and excellent in vivo biocompatibility. Over the last decade, material scientists have developed IONPs with better imaging and enhanced optical absorbance properties by tuning their sizes, shape, phases, and surface characterizations. Since IONPs could be detected with magnetic resonance imaging, various attempts have been made to combine other imaging modalities, thereby creating a high-resolution imaging platform. Composite IONPs (CIONPs) comprising IONP cores with polymeric or inorganic coatings have recently been documented as a promising modality for therapeutic applications. METHODS: In this review, we provide an overview of the recent advances in CIONPs for multimodal imaging and focus on the therapeutic applications of CIONPs. RESULTS: CIONPs with phototherapeutics, IONP-based nanoparticles are used for theranostic application via imaging guided photothermal therapy. CONCLUSION: CIONP-based nanoparticles are known for theranostic application, longstanding effects of composite NPs in in vivo systems should also be studied. Once such issues are fixed, multifunctional CIONP-based applications can be extended for theranostics of diverse medical diseases in the future.

Review on photoacoustic tomographic image reconstruction for acoustically heterogeneous tissues / 生物医学工程学杂志

Acoustic properties of biological tissues usually vary inhomogeneously in space. Tissues with different chemical composition often have different acoustic properties. The assumption of acoustic homogeneity may lead to blurred details, misalignment of targets and artifacts in the reconstructed photoacoustic tomography (PAT) images. This paper summarizes the main solutions to PAT imaging of acoustically heterogeneous tissues, including the variable sound speed and acoustic attenuation. The advantages and limits of the methods are discussed and the possible future development is prospected.

Preparation and characterization of the second near-infrared window fluorescent/photoacoustic imaging liposomes / 中国药科大学学报

@#The second near-infrared window(NIR-II)fluorescent dye IR-1061 has the disadvantage of poorwater solubility and low quantum yield, which limits its application in biomedicine. We used liposomes as the carrier to increase their water solubility, and co-loaded a near-infrared region(NIR-I)fluorescent dye IR-780 into liposomes to enhance the fluorescence intensity of IR-1061 in NIR-II. Results showed that the liposomes exhibited significantly enhanced characteristic fluorescence under 980 nm laser irradiation. In addition, particle size, appearance, photothermal conversion efficiency, photoacoustic performance and cytotoxicity of liposomes were examined. This study showed that these combined liposomes exhibited potential as a NIR-II fluorescence/photoacoustic bimodal imaging system for the diagnosis and guidance of tumor photothermal therapy.

Experimental study of hematoporphyrinmonomethyl ether based PLGA nanoparticles for photoacoustic imaging-guided sonodynamic therapy / 中国医学影像技术

Objective To prepare hematoporphyrinmonomethyl ether (HMME) based poly (lactic-co-glycolic acid) (PLGA) nanoparticles, and to investigate their enhancement effect on photoacoustic (PA) imaging and sonodynamic therapy (SDT) efficacy in vitro. Methods HMME-based PLGA (HMME@PLGA) nanoparticles were synthesized using a facile double emulsion strategy. The characteristics and enhanced PA imaging capability were observed in vitro. Upon ultrasound irradiation, the reactive oxygen species (ROS) generated with MDA-MB-231 cells up-taken HMME@PLGA was investigated using flow cytometry. SDT efficacy on cellular level was further investigated. Results The fabricated HMME@PLGA nanoparticles were demonstrated with homogenized size and distribution, and the average diameter was (333.67±17.50)nm. The Zeta potential was (-10.57±1.98)mV. The encapsulation efficiency of HMME in HMME@PLGA was 75.62%, and the drug loading was 2.90%. When incubation with HMME@PLGA nanoparticles (1 mg/ml) for 24 h, the viability of MDA-MB-231 cells was 87.21%. PA signal intensities increased with the increase of HMME@PLGA concentration in vitro. Upon ultrasound irradiation, ROS was produced in MDA-MB-231 cells with the assistance of HMME@PLGA nanoparticles, further leading to cytotoxic effects and cellular death which showed obvious red fluorescence stained with Calcein-AM/PI. Meanwhile, the lysosomes structures of the dead cells disappeared when stained by acridine orange. Conclusion HMME@PLGA nanoparticles are successfully fabricated and can achieve PA imaging-guided SDT.

Progresses of photoacoustic-ultrasonic combined imaging reconstruction / 中国医学影像技术

Ultrasonic computed tomography (USCT) and photoacoustic computed tomography (PACT) are two kinds of complementary imaging techniques. Photoacoustic-ultrasonic (PAUS) imaging combines PACT with USCT into one system and can obtain structural images and optical absorption distribution images of the target simultaneously. The combined images can display the acoustic discontinuity and optical absorption properties of the tissue. The diseased tissue can be accurately identified and located, and the functional components can also be quantitatively measured. The research progresses of the methods of joint images reconstruction for PAUS were reviewed in this paper.

Photoacoustic-based thermal image formation and optimization using an evolutionary genetic algorithm

Abstract Introduction For improved efficiency and security in heat application during hyperthermia, it is important to monitor tissue temperature during treatments. Photoacoustic (PA) pressure wave amplitude has a temperature dependence given by the Gruenesein parameter. Consequently, changes in PA signal amplitude carry information about temperature variation in tissue. Therefore, PA has been proposed as an imaging technique to monitor temperature during hyperthermia. However, no studies have compared the performance of different algorithms to generate PA-based thermal images. Methods Here, four methods to estimate variations in PA signal amplitude for thermal image formation were investigated: peak-to-peak, integral of the modulus, autocorrelation of the maximum value, and energy of the signal. Changes in PA signal amplitude were evaluated using a 1-D window moving across the entire image. PA images were acquired for temperatures ranging from 36oC to 41oC using a phantom immersed in a temperature controlled thermal bath. Results The results demonstrated that imaging processing parameters and methods involved in tracking variations in PA signal amplitude drastically affected the sensitivity and accuracy of thermal images formation. The sensitivity fluctuated more than 20% across the different methods and parameters used. After optimizing the parameters to generate the thermal images using an evolutionary genetic algorithm (GA), the percentage of pixels within the acceptable error was improved, in average, by 7.5%. Conclusion Optimization of processing parameters using GA could increase the accuracy of measurement for this experimental setup and improve quality of PA-based thermal images.

Focal zone integral and multiple axial scanning based acoustic resolution photoacoustic microscopy with high lateral resolution in-depth / 生物医学工程学杂志

Acoustic resolution photoacoustic microscopy (ARPAM) combines the advantages of high optical contrast, and high ultrasonic spatial resolution and penetration. However, in photoacoustic microscopy (PAM), the information from deep regions can be greatly affected by the shallow targets, and most importantly, the irreconcilable conflict between the lateral resolution and depth of fields has always be a major factor that limits the imaging quality. In this work, an ARPAM system was developed, in which a non-coaxial arrangement of light illumination and acoustic detection was adopted to alleviate the influence of the tissue surface on the deep targets, and a novel focal zone integral algorithm was applied with multiple axial scanning to improve the lateral resolution. Phantom experiment results show that, the build system can maintain a consistent high lateral resolution of 0.6 mm over a large range in axial direction, which is close to the theoretical calculations. The following tumor imaging results on nude mice indicate that, the proposed method can provide more in-depth information compared with the conventional back detection ARPAM method. With the development of fast repetition lasers and image scanning technologies, the proposed method may play an important role in cerebral vascular imaging, cervical cancer photoacoustic endoscopic detection, and superficial tumor imaging.

Simulation Platform of Photoacoustic Imaging Based on Finite Element and -space Pseudospectral Method / 中国医疗器械杂志

Numerical simulation is a powerful technology for photoacoustic imaging (PAI) in both theory studies and practical applications. In this paper, a simulation platform for PAI was designed and implemented based on Matlab. The simulation platform utilized finite element method (FEM) and -space pseudospectral method to calculate the forward and inverse problem of PAI. And a graphical user interface (GUI) was realized. Structural design, work process and other operating details of the platform was also provided. By compared with theoretical temporal waveform of photoacoustic signal and reconstruction results of COMSOL, the validity and reliability was verified. And a reliable simulation tool was proposed for PAI.

Recent developments in multimodality fluorescence imaging probes

Multimodality optical imaging probes have emerged as powerful tools that improve detection sensitivity and accuracy, important in disease diagnosis and treatment. In this review, we focus on recent developments of optical fluorescence imaging (OFI) probe integration with other imaging modalities such as X-ray computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), single-photon emission computed tomography (SPECT), and photoacoustic imaging (PAI). The imaging technologies are briefly described in order to introduce the strengths and limitations of each techniques and the need for further multimodality optical imaging probe development. The emphasis of this account is placed on how design strategies are currently implemented to afford physicochemically and biologically compatible multimodality optical fluorescence imaging probes. We also present studies that overcame intrinsic disadvantages of each imaging technique by multimodality approach with improved detection sensitivity and accuracy.

The combined therapeutic effects of iodine-labeled multifunctional copper sulfide-loaded microspheres in treating breast cancer

Compared to conventional cancer treatment, combination therapy based on well-designed nanoscale platforms may offer an opportunity to eliminate tumors and reduce recurrence and metastasis. In this study, we prepared multifunctional microspheres loading I-labeled hollow copper sulfide nanoparticles and paclitaxel (I-HCuSNPs-MS-PTX) for imaging and therapeutics of W256/B breast tumors in rats. F-fluordeoxyglucose (F-FDG) positron emission tomography/computed tomography (PET/CT) imaging detected that the expansion of the tumor volume was delayed (<0.05) following intra-tumoral (i.t.) injection with I-HCuSNPs-MS-PTX plus near-infrared (NIR) irradiation. The immunohistochemical analysis further confirmed the anti-tumor effect. The single photon emission computed tomography (SPECT)/photoacoustic imaging mediated by I-HCuSNPs-MS-PTX demonstrated that microspheres were mainly distributed in the tumors with a relatively low distribution in other organs. Our results revealed that I-HCuSNPs-MS-PTX offered combined photothermal, chemo- and radio-therapies, eliminating tumors at a relatively low dose, as well as allowing SPECT/CT and photoacoustic imaging monitoring of distribution of the injected agents non-invasively. The copper sulfide-loaded microspheres, I-HCuSNPs-MS-PTX, can serve as a versatile theranostic agent in an orthotopic breast cancer model.