In this paper, a novel reconstruction method is presented for Near Infrared (NIR) 2-D imaging to recover optical absorption coefficients from laboratory phantom data. The main body of this work validates a new generat...In this paper, a novel reconstruction method is presented for Near Infrared (NIR) 2-D imaging to recover optical absorption coefficients from laboratory phantom data. The main body of this work validates a new generation of highly efficient reconstruction algorithms called “Globally Convergent Method” (GCM) based upon actual measurements taken from brain-shape phantoms. It has been demonstrated in earlier studies using computer-simulated data that this type of reconstructions is stable for imaging complex distributions of optical absorption. The results in this paper demonstrate the excellent capability of GCM in working with experimental data measured from optical phantoms mimicking a rat brain with stroke.展开更多
Diffuse optical tomography (DOT) using near-infrared (NIR) light is a promising tool for noninvasive imaging of deep tissue. The approach is capable of reconstructing the quantitative optical parameters (absorption co...Diffuse optical tomography (DOT) using near-infrared (NIR) light is a promising tool for noninvasive imaging of deep tissue. The approach is capable of reconstructing the quantitative optical parameters (absorption coefficient and scattering coefficient) of a soft tissue. The motivation for reconstructing the optical property variation is that it and, in particular, the absorption coefficient variation, can be used to diagnose different metabolic and disease states of tissue. In DOT, like any other medical imaging modality, the aim is to produce a reconstruction with good spatial resolution and in contrast with noisy measurements. The parameter recovery known as inverse problem in highly scattering biological tissues is a nonlinear and ill-posed problem and is generally solved through iterative methods. The algorithm uses a forward model to arrive at a prediction flux density at the tissue boundary. The forward model uses light transport models such as stochastic Monte Carlo simulation or deterministic methods such as radioactive transfer equation (RTE) or a simplified version of RTE namely the diffusion equation (DE). The finite element method (FEM) is used for discretizing the diffusion equation. The frequently used algorithm for solving the inverse problem is Newton-based Model based Iterative Image Reconstruction (N-MoBIIR). Many Variants of Gauss-Newton approaches are proposed for DOT reconstruction. The focuses of such developments are 1) to reduce the computational complexity;2) to improve spatial recovery;and 3) to improve contrast recovery. These algorithms are 1) Hessian based MoBIIR;2) Broyden-based MoBIIR;3) adjoint Broyden-based MoBIIR;and 4) pseudo-dynamic approaches.展开更多
AIM： To elucidate the relationship between systemic risk factors and different patterns of diabetic macular edema（DME） determined with optical coherence tomography（OCT）. METHODS： In this cross-sectional study, D...AIM： To elucidate the relationship between systemic risk factors and different patterns of diabetic macular edema（DME） determined with optical coherence tomography（OCT）. METHODS： In this cross-sectional study, DME was classified by OCT as diffuse retinal thickness（DRT）, cystoid macular edema（CME） and serous retinal detachment（SRD） and the relationship between the systemic risk factors and DME patterns was evaluated. RESULTS： Of the 57 patients with DME, 21（36.8%） had DRT, 24（42.1%） had CME and 12（21.0%） had SRD. Microor macro-albuminuria was significantly higher in the DRT pattern（61.9%） compared with the SRD（50.0%） and CME patterns（25.0%; P=0.040）. Hemoglobin A1 c（Hb A1 c） level was significantly higher and patients were younger in the DRT pattern group（P=0.034, P=0.032）. Best corrected visual acuity was the worst and central macular thickness was the thickest in the CME pattern group. CONCLUSION： Micro-or macro-albuminuria may be more frequent and Hb A1 c level may be higher in patients with DRT. These patients are also seen to be younger than patients with non-DRT.展开更多
The concept of region of sensitivity is central to the field of diffuse optics and is closely related to the Jacobian matrix used to solve the inverse problem in imaging.It is well known that,in diffuse reflectance,th...The concept of region of sensitivity is central to the field of diffuse optics and is closely related to the Jacobian matrix used to solve the inverse problem in imaging.It is well known that,in diffuse reflectance,the region of sensitivity associated with a given source-detector pair is shaped as a banana,and features maximal sensitivity to the portions of the sample that are closest to the source and the detector.We have recently introduced a dual-slope(DS)method based on a special arrangement of two sources and two detectors,which results in deeper and more localized regions of sensitivity,resembling the shapes of different kinds of nuts.Here,we report the regions of sensitivity associated with a variety of source-detector arrangements for DS measurements of intensity and phase with frequency-domain spectroscopy(modulation frequency:140 MHz)in a medium with absorption and reduced scattering coefficients of 0.1 and 12 cm^(-1),respectively.The main result is that the depth of maximum sensitivity,considering only cases that use source-detector separations of 25 and 35 mm,progressively increases as we consider single-distance intensity(2.0mm),DS intensity(4.6mm),single-distance phase(7.5mm),and DS phase(10.9 mm).These results indicate the importance of DS measurements,and even more so of phase measurements,when it is desirable to selectively probe deeper portions of a sample with diffuse optics.This is certainly the case in non-invasive optical studies of brain,muscle,and breast tissue,which are located underneath the superficial tissue at variable depths.展开更多
Transcranial magnetic stimulation(TMS)has been established as an important and effective treatment for various psychiatric disorders.However,its effectiveness has likely been limited due to the dearth of neuronavigati...Transcranial magnetic stimulation(TMS)has been established as an important and effective treatment for various psychiatric disorders.However,its effectiveness has likely been limited due to the dearth of neuronavigational tools for targeting purposes,unclear ideal stimulation parameters,and a lack of knowledge regarding the physiological response of the brain to TMS in each psychiatric condition.Modern optical imaging modalities,such as functional near-infrared spectroscopy and diffuse optical tomography,are promising tools for the study of TMS optimization and functional targeting in psychiatric disorders.They possess a unique combination of high spatial and temporal resolutions,portability,real-time capability,and relatively low costs.In this mini-review,we discuss the advent of optical imaging techniques and their innovative use in several psychiatric conditions including depression,panic disorder,phobias,and eating disorders.With further investment and research in the development of these optical imaging approaches,their potential will be paramount for the advancement of TMS treatment protocols in psychiatry.展开更多
The utility of optical coherence tomography signal amplitudemeasurement to monitorglucose concentration in tissue phantom and blood samples from human subjectshas been explored. The diffusion equation based calculatio...The utility of optical coherence tomography signal amplitudemeasurement to monitorglucose concentration in tissue phantom and blood samples from human subjectshas been explored. The diffusion equation based calculations as well as invivo OCT signal measurements confirm a cyclic correlation of signal intensity with glucose concentration and scatterer size.展开更多
AIM:To explore the morphological and functional parameters to evaluate the effectiveness of intravitreal injections of ranibizumab(IVR)in treating macular edema(ME)secondary to retinal vein occlusion(RVO).METHODS:This...AIM:To explore the morphological and functional parameters to evaluate the effectiveness of intravitreal injections of ranibizumab(IVR)in treating macular edema(ME)secondary to retinal vein occlusion(RVO).METHODS:This retrospective study involved 65 RVO patients(65 eyes)who received IVR and were followedup for more than 3mo.ME was categorized into cystoid macular edema(CME),diffuse retinal thickening(DRT),and serous retinal detachment(SRD)according to optical coherence tomography(OCT)images.The comparison of best corrected visual acuity(BCVA;logMAR)and central macular thickness(CMT)among different follow-up points and those among 3 groups were performed by Kruskal-Wallis test.The correlation between BCVA and baseline parameters during treatment was analyzed using Spearman correlation analysis.RESULTS:BCVA tended to improve in all groups,with marked improvement in CME and DRT groups.CMT showed the greatest reduction after 1wk,and remained stable over the following 3mo.DRT patients had the worst BCVA and the highest CMT at baseline,but the differences became smaller after IVR treatment.CMT in SRD group was significantly better than in CME and DRT groups 3mo after IVR.Most patients of CME and SRD groups transitioned to a normal pattern at 3mo follow-up.DRT patients were most likely to transform into the other morphological groups,while SRD patients showed minimal transitions.BCVA at baseline was identified as the most important prognostic indicator in all 3 groups.Additionally,DRT patients with a longer clinical course,higher CMT and central retinal vein occlusion(CRVO)tend to exhibit worse BCVA after treatment.In addition,CRVO patients are more likely to have worse BCVA at 2 and 3mo follow-up compared with branch retinal vein occlusion(BRVO)patients in CME group.SRD patients with higher baseline CMT were prone to experiencing worse BCVA after treatment.CONCLUSION:The effectiveness of IVR is strongly correlated with baseline BCVA in all 3 groups.Baseline parameters including clinical course,CMT,and RVO position are also useful in predicting the BCVA at different time points after treatment.展开更多
In this paper, an EM-like image reconstruction iterative formula specifically developed for stable external sources is rewritten as a map towards a fixed point iteration. Eocal con- vergence of the image reconstructio...In this paper, an EM-like image reconstruction iterative formula specifically developed for stable external sources is rewritten as a map towards a fixed point iteration. Eocal con- vergence of the image reconstruction method is then proved. Finally a three-dimensional numerical image reconstruction example is presented.展开更多
文摘In this paper, a novel reconstruction method is presented for Near Infrared (NIR) 2-D imaging to recover optical absorption coefficients from laboratory phantom data. The main body of this work validates a new generation of highly efficient reconstruction algorithms called “Globally Convergent Method” (GCM) based upon actual measurements taken from brain-shape phantoms. It has been demonstrated in earlier studies using computer-simulated data that this type of reconstructions is stable for imaging complex distributions of optical absorption. The results in this paper demonstrate the excellent capability of GCM in working with experimental data measured from optical phantoms mimicking a rat brain with stroke.
文摘Diffuse optical tomography (DOT) using near-infrared (NIR) light is a promising tool for noninvasive imaging of deep tissue. The approach is capable of reconstructing the quantitative optical parameters (absorption coefficient and scattering coefficient) of a soft tissue. The motivation for reconstructing the optical property variation is that it and, in particular, the absorption coefficient variation, can be used to diagnose different metabolic and disease states of tissue. In DOT, like any other medical imaging modality, the aim is to produce a reconstruction with good spatial resolution and in contrast with noisy measurements. The parameter recovery known as inverse problem in highly scattering biological tissues is a nonlinear and ill-posed problem and is generally solved through iterative methods. The algorithm uses a forward model to arrive at a prediction flux density at the tissue boundary. The forward model uses light transport models such as stochastic Monte Carlo simulation or deterministic methods such as radioactive transfer equation (RTE) or a simplified version of RTE namely the diffusion equation (DE). The finite element method (FEM) is used for discretizing the diffusion equation. The frequently used algorithm for solving the inverse problem is Newton-based Model based Iterative Image Reconstruction (N-MoBIIR). Many Variants of Gauss-Newton approaches are proposed for DOT reconstruction. The focuses of such developments are 1) to reduce the computational complexity;2) to improve spatial recovery;and 3) to improve contrast recovery. These algorithms are 1) Hessian based MoBIIR;2) Broyden-based MoBIIR;3) adjoint Broyden-based MoBIIR;and 4) pseudo-dynamic approaches.
文摘AIM： To elucidate the relationship between systemic risk factors and different patterns of diabetic macular edema（DME） determined with optical coherence tomography（OCT）. METHODS： In this cross-sectional study, DME was classified by OCT as diffuse retinal thickness（DRT）, cystoid macular edema（CME） and serous retinal detachment（SRD） and the relationship between the systemic risk factors and DME patterns was evaluated. RESULTS： Of the 57 patients with DME, 21（36.8%） had DRT, 24（42.1%） had CME and 12（21.0%） had SRD. Microor macro-albuminuria was significantly higher in the DRT pattern（61.9%） compared with the SRD（50.0%） and CME patterns（25.0%; P=0.040）. Hemoglobin A1 c（Hb A1 c） level was significantly higher and patients were younger in the DRT pattern group（P=0.034, P=0.032）. Best corrected visual acuity was the worst and central macular thickness was the thickest in the CME pattern group. CONCLUSION： Micro-or macro-albuminuria may be more frequent and Hb A1 c level may be higher in patients with DRT. These patients are also seen to be younger than patients with non-DRT.
基金This research was supported by NIH Grant No.R01-NS095334.
文摘The concept of region of sensitivity is central to the field of diffuse optics and is closely related to the Jacobian matrix used to solve the inverse problem in imaging.It is well known that,in diffuse reflectance,the region of sensitivity associated with a given source-detector pair is shaped as a banana,and features maximal sensitivity to the portions of the sample that are closest to the source and the detector.We have recently introduced a dual-slope(DS)method based on a special arrangement of two sources and two detectors,which results in deeper and more localized regions of sensitivity,resembling the shapes of different kinds of nuts.Here,we report the regions of sensitivity associated with a variety of source-detector arrangements for DS measurements of intensity and phase with frequency-domain spectroscopy(modulation frequency:140 MHz)in a medium with absorption and reduced scattering coefficients of 0.1 and 12 cm^(-1),respectively.The main result is that the depth of maximum sensitivity,considering only cases that use source-detector separations of 25 and 35 mm,progressively increases as we consider single-distance intensity(2.0mm),DS intensity(4.6mm),single-distance phase(7.5mm),and DS phase(10.9 mm).These results indicate the importance of DS measurements,and even more so of phase measurements,when it is desirable to selectively probe deeper portions of a sample with diffuse optics.This is certainly the case in non-invasive optical studies of brain,muscle,and breast tissue,which are located underneath the superficial tissue at variable depths.
文摘Transcranial magnetic stimulation(TMS)has been established as an important and effective treatment for various psychiatric disorders.However,its effectiveness has likely been limited due to the dearth of neuronavigational tools for targeting purposes,unclear ideal stimulation parameters,and a lack of knowledge regarding the physiological response of the brain to TMS in each psychiatric condition.Modern optical imaging modalities,such as functional near-infrared spectroscopy and diffuse optical tomography,are promising tools for the study of TMS optimization and functional targeting in psychiatric disorders.They possess a unique combination of high spatial and temporal resolutions,portability,real-time capability,and relatively low costs.In this mini-review,we discuss the advent of optical imaging techniques and their innovative use in several psychiatric conditions including depression,panic disorder,phobias,and eating disorders.With further investment and research in the development of these optical imaging approaches,their potential will be paramount for the advancement of TMS treatment protocols in psychiatry.
文摘The utility of optical coherence tomography signal amplitudemeasurement to monitorglucose concentration in tissue phantom and blood samples from human subjectshas been explored. The diffusion equation based calculations as well as invivo OCT signal measurements confirm a cyclic correlation of signal intensity with glucose concentration and scatterer size.
基金Supported by the Suzhou Medical Innovation Application Research Project(SZM2023027).
文摘AIM:To explore the morphological and functional parameters to evaluate the effectiveness of intravitreal injections of ranibizumab(IVR)in treating macular edema(ME)secondary to retinal vein occlusion(RVO).METHODS:This retrospective study involved 65 RVO patients(65 eyes)who received IVR and were followedup for more than 3mo.ME was categorized into cystoid macular edema(CME),diffuse retinal thickening(DRT),and serous retinal detachment(SRD)according to optical coherence tomography(OCT)images.The comparison of best corrected visual acuity(BCVA;logMAR)and central macular thickness(CMT)among different follow-up points and those among 3 groups were performed by Kruskal-Wallis test.The correlation between BCVA and baseline parameters during treatment was analyzed using Spearman correlation analysis.RESULTS:BCVA tended to improve in all groups,with marked improvement in CME and DRT groups.CMT showed the greatest reduction after 1wk,and remained stable over the following 3mo.DRT patients had the worst BCVA and the highest CMT at baseline,but the differences became smaller after IVR treatment.CMT in SRD group was significantly better than in CME and DRT groups 3mo after IVR.Most patients of CME and SRD groups transitioned to a normal pattern at 3mo follow-up.DRT patients were most likely to transform into the other morphological groups,while SRD patients showed minimal transitions.BCVA at baseline was identified as the most important prognostic indicator in all 3 groups.Additionally,DRT patients with a longer clinical course,higher CMT and central retinal vein occlusion(CRVO)tend to exhibit worse BCVA after treatment.In addition,CRVO patients are more likely to have worse BCVA at 2 and 3mo follow-up compared with branch retinal vein occlusion(BRVO)patients in CME group.SRD patients with higher baseline CMT were prone to experiencing worse BCVA after treatment.CONCLUSION:The effectiveness of IVR is strongly correlated with baseline BCVA in all 3 groups.Baseline parameters including clinical course,CMT,and RVO position are also useful in predicting the BCVA at different time points after treatment.
文摘In this paper, an EM-like image reconstruction iterative formula specifically developed for stable external sources is rewritten as a map towards a fixed point iteration. Eocal con- vergence of the image reconstruction method is then proved. Finally a three-dimensional numerical image reconstruction example is presented.
