Near-infrared Spectral Tomography Research Articles

Near-Infrared Spectral Tomography for Predicting Residual Cancer Burden during Early-Stage Neoadjuvant Chemotherapy for Breast Cancer.

The aim of this study is to investigate whether near-infrared spectral tomography (NIRST) might serve as a reliable prognostic tool to predict residual cancer burden (RCB) in patients with breast cancer undergoing neoadjuvant chemotherapy (NAC) based upon early treatment response measurements. A total of thirty-five patients with breast cancer receiving NAC were included in this study. NIRST imaging was performed at multiple time points, including: before treatment, at end of the first cycle, at the mid-point, and post-NAC treatments. From reconstructed NIRST images, average values of total hemoglobin (HbT) were obtained for both the tumor region and contralateral breast at each time point. RCB scores/classes were assessed by a pathologist using histologic slides of the surgical specimen obtained after completing NAC. Logistic regression of the normalized early percentage change of HbT in the tumor region (ΔHbT%) was used to predict RCB and determine its significance as an indicator for differentiating cases within each RCB class. The ΔHbT% at the end of the first cycle, as compared with pretreatment levels, showed excellent prognostic capability in differentiating RCB-0 from RCB-I/II/III or RCB-II from RCB-0/I/III (P < 0.001). Corresponding area under the curve (AUC) values for these comparisons were 0.97 and 0.94, and accuracy values were 0.90 and 0.83, respectively. NIRST holds promise as a potential clinical tool that can be seamlessly integrated into existing clinical workflow within the infusion suite. By providing early assessment of RCB, NIRST has potential to improve breast cancer patient management strategies.

Deep-learning based image reconstruction for MRI-guided near-infrared spectral tomography

Non-invasive near-infrared spectral tomography (NIRST) can incorporate the structural information provided by simultaneous magnetic resonance imaging (MRI), and this has significantly improved the images obtained of tissue function. However, the process of MRI guidance in NIRST has been time consuming because of the needs for tissue-type segmentation and forward diffuse modeling of light propagation. To overcome these problems, a reconstruction algorithm for MRI-guided NIRST based on deep learning is proposed and validated by simulation and real patient imaging data for breast cancer characterization. In this approach, diffused optical signals and MRI images were both used as the input to the neural network, and simultaneously recovered the concentrations of oxy-hemoglobin, deoxy-hemoglobin, and water via end-to-end training by using 20,000 sets of computer-generated simulation phantoms. The simulation phantom studies showed that the quality of the reconstructed images was improved, compared to that obtained by other existing reconstruction methods. Reconstructed patient images show that the well-trained neural network with only simulation data sets can be directly used for differentiating malignant from benign breast tumors.

Performance assessment of MRI guided continuous wave near-infrared spectral tomography for breast imaging.

Integration of magnetic resonance imaging (MRI) and near-infrared spectral tomography (NIRST) has yielded promising diagnostic performance for breast imaging in the past. This study focused on whether MRI-guided NIRST can quantify hemoglobin concentration using only continuous wave (CW) measurements. Patients were classified into four breast density groups based on their MRIs. Optical scattering properties were assigned based on average values obtained from these density groups, and MRI-guided NIRST images were reconstructed from calibrated CW data. Total hemoglobin (HbT) contrast between suspected lesions and surrounding normal tissue was used as an indicator of the malignancy. Results obtained from simulations and twenty-four patient cases indicate that the diagnostic power when using only CW data to differentiate malignant from benign abnormalities is similar to that obtained from combined frequency domain (FD) and CW data. These findings suggest that eliminating FD detection to reduce the cost and complexity of MRI-guided NIRST is possible.

Current concepts on ocular vascular abnormalities in the phakomatoses

ABSTRACT Background: Neurofibromatosis, Von Hippel Lindau disease, and tuberous sclerosis complex are classified under the term phakomatoses. They are characterized by ocular vascular abnormalities such as vascular tortuosity, corkscrew retinal vessel configuration, moyamoya-like aspect, microaneurysms, hemangioblastomas, and focal sheathing of retinal arteries, possibly due to abnormal formation, migration, and differentiation of neural crest cells. These alterations can be the first sign or the hallmark of disease and can be related to vasoproliferative tumors. Purpose: Novel imaging technologies in ophthalmology, such as near-infrared reflectances and spectral domain optical coherence tomography, have improved our knowledge in the diagnosis of these pathologies. Previously undetected macular vascular alterations have been reported in phakomatoses using optical coherence tomography angiography. This review will summarize the ophthalmic vascular abnormalities and novel imaging methods in the phakomatoses. Conclusion: Active research is being led into the ophthalmic management of these conditions and their complications, and owing to elevated vascular endothelial growth factor production from hemangioblastoma, hamartoma, and retinal vascular proliferative tumors, increasing interest in this line of therapy has been conducted although research is still ongoing in this area.

Pentosan Polysulfate Maculopathy: Prevalence, Spectrum of Disease, and Choroidal Imaging Analysis Based on Prospective Screening

Purpose: To describe the prevalence and spectrum of disease of pentosan polysulfate (PPS) maculopathy in a large multimodal retinal imaging study and to report the results of choroidal vascularity index (CVI) analysis.Design: Prospective cohort studyMethods: Of 741 patients prescribed PPS within a large university database, 100 (13.4%) with any consumption agreed to participate in a prospective screening investigation. Multimodal retinal imaging including near-infrared reflectance (NIR), fundus autofluorescence (FAF), and spectral domain optical coherence tomography (SD-OCT) was performed in all patients. Characteristic findings of affected patients were identified, and affected and unaffected cohorts were compared. CVI, defined as stromal choroidal area (SCA) divided by the total choroidal area, was analyzed.Results: The prevalence of PPS maculopathy was 16%. NIR illustrated punctate hyperreflective lesions with early presentation. FAF illustrated a speckled macular network of hypo- and hyperautofluorescence colocalized with multifocal hyperreflective retinal pigment epithelial lesions on SD-OCT. Advanced cases demonstrated varying degrees of atrophy. The affected cohort exhibited significantly greater mean PPS therapy duration, mean daily dosage, and mean cumulative dosage (19.5±5.5 years, 433.9±137.6 mg, 3,103.1±1,402.2 g) compared with the unaffected cohort (7.1±6.6 years, 291.6±177.6 mg, 768.4±754.8 g). SCA was significantly lower and CVI was significantly greater in the affected vs the unaffected group.Conclusions: This prospective cohort study identified a prevalence of PPS maculopathy of 15%-20% among PPS users who agreed to participate. A spectrum of findings may be observed with multimodal retinal imaging. Significant choroidal abnormalities associated with this characteristic maculopathy may provide surrogate markers of macular toxicity.

Predicting visual acuity in Bietti crystalline dystrophy: evaluation of image parameters

BackgroundTo analyze multiple imaging modalities in patients with Bietti crystalline dystrophy (BCD) and to investigate which factors from these modalities are associated with best corrected visual acuity (BCVA).MethodsIn this retrospective study, 40 eyes from 22 patients with BCD were included and were separated into group 1 (BCVA ≤20/200) and group 2 (BCVA > 20/200). Data including BCVA and characteristic findings from near-infrared reflectance (NIR) imaging, fundus autofluorescence (FAF), and spectral domain-optic coherence tomography (SD-OCT) were analyzed and compared. The outcome measures of multimodal imaging were evaluated for correlation with BCVA.ResultsNIR is a good diagnostic tool for detecting either crystalline or sclerotic vessels in BCD. Patients in group 1 tended to have a thinner choroid (P = 0.047) with ellipsoid zone (EZ) disruption (P = 0.011). Calculation of the area under the curve indicated that EZ disruption detected on SD-OCT could be a good predictor of legal blindness in BCD.ConclusionFor the diagnosis of BCD, NIR could be a good diagnostic tool. Of the studied imaging modalities, we found that EZ disruption at the fovea were strongly associated with legal blindness, which could be easily assessed by SD-OCT.

Numerical Simulation of a Scanning Illumination System for Deep Tissue Fluorescence Imaging.

The spatial resolution and light detected in fluorescence imaging for small animals are limited by light scattering, absorption and autofluorescence. To address this, novel near-infrared fluorescent contrast agents and imaging configurations have been investigated. In this paper, the influence of the light wavelength and imaging configurations (full-field illumination system and scanning system) on fluorescence imaging are compared quantitatively. The surface radiance for both systems is calculated by modifying the simulation tool Near-Infrared Fluorescence and Spectral Tomography. Fluorescent targets are embedded within a scattering medium at different positions. The surface radiance and spatial resolution are obtained for emission wavelengths between 620 nm and 1000 nm. It was found that the spatial resolution of the scanning system is independent of the tissue optical properties, whereas for full-field illumination, the spatial resolution degrades at longer wavelength. The full width at half maximum obtained by the scanning system is 25% lower than that obtained by the full-field illumination system when the targets are located in the middle of the phantom. The results indicate that although imaging at near-infrared wavelength can achieve a higher surface radiance, it may produce worse spatial resolution.

Noncontact Speckle Contrast Diffuse Correlation Tomography of Blood Flow Distributions in Burn Wounds: A Preliminary Study.

Tissue injuries are often associated with abnormal blood flow (BF). The ability to assess BF distributions in injured tissues enables objective evaluation of interventions and holds the potential to improve the acute management of these injuries on battlefield. We have developed a novel speckle contrast diffuse correlation tomography (scDCT) system for noncontact 3D imaging of tissue BF distributions. In scDCT, a galvo mirror was used to remotely project near-infrared point light to different source positions and an electron multiplying charge-coupled-device was used to detect boundary diffuse speckle contrasts. The normalized boundary data were then inserted into a modified Near-Infrared Fluorescence and Spectral Tomography program for 3D reconstructions of BF distributions. This article reports the first application of scDCT for noncontact 3D imaging of BF distributions in burn wounds. Significant lower BF values were observed in the burned areas/volumes compared to surrounding normal tissues. The unique noncontact 3D imaging capability makes the scDCT applicable for intraoperative assessment of burns/wounds, without risk of infection and without interfering with sterility of the surgical field. The portable scDCT device holds the potential to be used by surgeons in combat surgical hospitals to improve the acute management of battlefield burn injuries.

Long-Term Incidence and Growth of Chorioretinal Atrophy in Patients with Polypoidal Choroidal Vasculopathy

Purpose: To investigate the long-term incidence and growth rate of chorioretinal atrophy (CRA) in patients with polypoidal choroidal vasculopathy (PCV) and determine the associated risk factors. Methods: The medical records of 88 patients with unilateral symptomatic PCV who received anti-vascular endothelial growth factor (anti-VEGF) injections with or without photodynamic therapy (PDT) were analyzed retrospectively. Near-infrared fundus imaging and spectral domain optical coherence tomography were used to measure the CRA area and growth rate. Kaplan-Meier survival analysis was performed to estimate the CRA incidence. Logistic and linear regression analyses were used to investigate risk factors (e.g., age, frequency of abnormal OCT findings, PDT history, total injection number, and choroidal thickness) associated with the CRA incidence and growth rate, respectively. Results: The overall CRA incidence was 40.8% at 5 years. The absence of subretinal fluid, the presence of intraretinal fluid, and a thin choroid were significant risk factors for CRA occurrence with a history of PDT. Overall 5-year CRA growth rate was 0.69 mm²/year. Faster CRA growth was significantly related to the presence of subretinal hyperreflective material and thin choroid. PDT history was not significantly related to CRA growth. Conclusions: Thin choroid may be a significant risk factor for long-term development and growth of CRA in eyes with PCV. Intraretinal fluid seems to promote the development of CRA, while subretinal fluid seems to be associated with CRA prevention. The history of PDT was significantly related to the occurrence of CRA, but not to the growth rate of CRA.

Abstract P6-02-02: Near-infrared spectral tomography (NIRST): A prognostic assessment tool for predicting residual cancer burden (RCB) during neoadjuvant chemotherapy (NAC) in breast cancer (BC)

Abstract Background: NIRST, a noninvasive imaging with no ionizing radiation, has been found to be prognostic as a tool to monitor early pathologic response to NAC in BC using biophysical properties of the tumor compared with normal breast tissue. We aim to establish NIRST indicators as early surrogates of treatment response and to evaluate its potential as a predictive tool in treatment decisions. Methods: 27 women with locally advanced BC undergoing NAC were enrolled in this pilot study. NIRST imaging was performed pre-treatment, after cycle 1 and 2, at the mid-point of NAC, and at the conclusion of NAC prior to surgery. Biophysical data including oxy- and deoxy-hemoglobin, water, lipid, and scatter components were obtained at these time points. To minimize inter-subject variability due to breast density and its effects on the NIRST data, statistical analysis was conducted using ratios of obtained biophysical data to pretreatment average of the contralateral normal breast tissue. Residual Cancer Burden (RCB) index was used to evaluate residual disease after treatment with NAC. RCB scores and classes were determined in 24 of the 27 surgical tissue specimens and these were compared to the NIRST data. RCB data for 3 patients were excluded: 2 patients had undergone positive excisional lymph node biopsy prior to NAC and 1 patient had surgery at an outside hospital. Results: Of the 27 patients, 7 had triple negative BC and 13 had HER-2 positive BC. The change in total hemoglobin (ΔHb-T %) after the first cycle of NAC when compared to the pre-treatment total hemoglobin was determined to be the best predicting factor for RCB (p-value &amp;lt;0.001). The Pearson correlation coefficient was calculated for both RBC class and RBC score (0.7 and 0.6). The significance of the correlation coefficient was evaluated using two-sided t-test and the resulting P-values of 0.006 and 0.001 respectively demonstrate that these correlations are statistically significant. Summary of the NIRST biophysical data and the correlating RCBPatientAgeERPRHer2RCB ScoreHbT -ΔHbT-pre136+-+0-139.933.30251---0-43.532.53341+++0-42.281.89430---0-43.061.59552---0-42.541.71663+++0-151.883.12760--+0-46.471.59852---0-42.721.96966--+0-110.022.471039--+0-9.091.101171+-+0-13.331.501252++-4.12153.201.581362++-3.7475.741.531470--+1.931100.521.631553++-3.4447.831.181641+++4.18929.841.511756+++4.44459.001.471850++-4.008-41.112.181954---3.05011.111.802063++-2.90020.001.502149---0.78026.321.902257++-1.8505.881.702347++-3.600-7.692.602470---3.10047.061.70 Conclusions: We have demonstrated a statistically significant correlation between ΔHb-T % after the first cycle of NAC and the RCB. These findings suggest the potential of using NIRST as an early assessment tool to evaluate response to NAC in BC patients and warrant further evaluation in a larger study. Citation Format: Batukbhai B, Jiang S, Bernhardt EB, Muller K, Cao X, Gui J, DiFlorio-Alexander RM, Chamberlin MD, Schwartz GN, Paulsen KD, Pogue BW, Kaufman PA. Near-infrared spectral tomography (NIRST): A prognostic assessment tool for predicting residual cancer burden (RCB) during neoadjuvant chemotherapy (NAC) in breast cancer (BC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-02-02.

Weighting function effects in a direct regularization method for image-guided near-infrared spectral tomography of breast cancer.

Structural image-guided near-infrared spectral tomography (NIRST) has been developed as a way to use diffuse NIR spectroscopy within the context of image-guided quantification of tissue spectral features. A direct regularization imaging (DRI) method for NIRST has the value of not requiring any image segmentation. Here, we present a comprehensive investigational study to analyze the impact of the weighting function implied when weighting the recovery of optical coefficients in DRI based NIRST. This was done using simulations, phantom and clinical patient exam data. Simulations where the true object is known indicate that changes to this weighting function can vary the contrast by 10%, the contrast to noise ratio by 20% and the full width half maximum (FWHM) by 30%. The results from phantoms and human images show that a linear inverse distance weighting function appears optimal, and that incorporation of this function can generally improve the recovered total hemoglobin contrast of the tumor to the normal surrounding tissue by more than 15% in human cases.

Correlation of near-infrared spectral tomography (NIRST) with residual cancer burden (RCB) for prognostic assessment subsequent to neoadjuvant chemotherapy (NAC) in breast cancer.

e12655 Background: NIRST provides biophysical data including oxy- and deoxy-hemoglobin, water, lipid, and scatter components, useful in distinguishing cancer from normal breast tissue. Unlike anatomic changes characterized by conventional radiographic techniques, these functional changes are uniquely suited to monitor early response to NAC. The Residual Cancer Burden (RCB) is a reproducible pathologic analysis to evaluate residual disease after treatment with NAC and proven useful prognostically. Methods: 19 women with locally advanced breast cancer were enrolled in this NIRST pilot study to evaluate tumor response to NAC. Patients underwent NIRST prior to NAC (HbT-pre), after cycle 1, after cycle 2, at the mid-point of NAC, and at the conclusion of NAC. RCB scores were determined in 16 of the 19 final tissue specimens. RCB scores for two patients were excluded due to positive excisional lymph node biopsy prior to NAC. One patient underwent surgery at an outside hospital and was excluded as pathology slides were unavailable. The RCB class was compared to NIRST biophysical data at time points throughout NAC. Ratios relative to the pretreatment average of the normal contralateral breast were used for statistical analysis to minimize inter-subject variability of breast density and the effect on biophysical data. Results: The best predictor for RCB class was the early change in total hemoglobin (HbT-Δ) (percent change when comparing the first cycle of NAC to HbT-pre), as analyzed by Pearson correlation coefficient of 0.71. The significance of this correlation was evaluated using a two-sided t-test. The resulting P-value of 0.0019 demonstrates a statistically significant correlation. Conclusions: In this pilot study of NIRST, we demonstrate a statistically significant correlation between HbT-Δ change during the first cycle of NAC and the RCB. These findings suggest the potential utility of this approach, and warrant further evaluation in a larger study. The ability to determine response within the first cycle of NAC would be of great clinical utility, and additionally of potential use in clinical trials involving novel neoadjuvant therapies.

Direct Regularization From Co-Registered Contrast MRI Improves Image Quality of MRI-Guided Near-Infrared Spectral Tomography of Breast Lesions.

An approach using direct regularization from co-registered dynamic contrast enhanced magnetic reson- ance images was used to reconstruct near-infrared spectral tomography patient images, which does not need image segmentation. 20 patients with mammography/ultrasound confirmed breast abnormalities were involved in this paper, and the resulting images indicated that tumor total hemoglobin concentration contrast differentiated malignant from benign cases (p-value = 0.021). The approach prod- uced reconstructed images, which significantly reduced surface artifacts near the source-detector locations (p-value = 4.16e-6).

Addition of T2-guided optical tomography improves noncontrast breast magnetic resonance imaging diagnosis

BackgroundWhile dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) is recognized as the most sensitive examination for breast cancer detection, it has a substantial false positive rate and gadolinium (Gd) contrast agents are not universally well tolerated. As a result, alternatives to diagnosing breast cancer based on endogenous contrast are of growing interest. In this study, endogenous near-infrared spectral tomography (NIRST) guided by T2 MRI was evaluated to explore whether the combined imaging modality, which does not require contrast injection or involve ionizing radiation, can achieve acceptable diagnostic performance.MethodsTwenty-four subjects—16 with pathologically confirmed malignancy and 8 with benign abnormalities—were simultaneously imaged with MRI and NIRST prior to definitive pathological diagnosis. MRIs were evaluated independently by three breast radiologists blinded to the pathological results. Optical image reconstructions were constrained by grayscale values in the T2 MRI. MRI and NIRST images were used, alone and in combination, to estimate the diagnostic performance of the data. Outcomes were compared to DCE results.ResultsSensitivity, specificity, accuracy, and area under the curve (AUC) of noncontrast MRI when combined with T2-guided NIRST were 94%, 100%, 96%, and 0.95, respectively, whereas these values were 94%, 63%, 88%, and 0.81 for DCE MRI alone, and 88%, 88%, 88%, and 0.94 when DCE-guided NIRST was added.ConclusionIn this study, the overall accuracy of imaging diagnosis improved to 96% when T2-guided NIRST was added to noncontrast MRI alone, relative to 88% for DCE MRI, suggesting that similar or better diagnostic accuracy can be achieved without requiring a contrast agent.

Collagen quantification in breast tissue using a 12-wavelength near infrared spectral tomography (NIRST) system.

A portable near infrared spectral tomography (NIRST) system was adapted for breast cancer detection and treatment monitoring with improved speed of acquisition for parallel 12 wavelengths of parallel frequency-domain (FD) and continuous-wavelength (CW) measurement. Using a novel gain adjustment scheme in the Photomultiplier Tube detectors (PMTs), the data acquisition time for simultaneous acquisition involving three FD and three CW wavelengths, has been reduced from 90 to 55 seconds, while signal variation was also reduced from 2.1% to 1.1%. Tomographic images of breast collagen content have been recovered for the first time, and image reconstruction approaches with and without collagen content included have been validated in simulation studies and normal subject exams. Simulations indicate that including collagen content into the reconstruction procedure can significantly reduce the overestimation in total hemoglobin, water and lipid by 8.9μM, 1.8% and 15.8%, respectively, and underestimates in oxygen saturation by 9.5%, given an average 10% background collagen content. A breast cancer patient with invasive ductal carcinoma was imaged and the reconstructed images show that the recovered tumor/background contrast in total hemoglobin increased from 1.5 to 1.7 when collagen was included in reconstruction.

Effects of breast density and compression on normal breast tissue hemodynamics through breast tomosynthesis guided near-infrared spectral tomography.

Optically derived tissue properties across a range of breast densities and the effects of breast compression on estimates of hemoglobin, oxygen metabolism, and water and lipid concentrations were obtained from a coregistered imaging system that integrates near-infrared spectral tomography (NIRST) with digital breast tomosynthesis (DBT). Image data were analyzed from 27 women who underwent four IRB approved NIRST/DBT exams that included fully and mildly compressed breast acquisitions in two projections—craniocaudal (CC) and mediolateral-oblique (MLO)—and generated four data sets per patient (full and moderate compression in CC and MLO views). Breast density was correlated with HbT (r=0.64, p=0.001), water (r=0.62, p=0.003), and lipid concentrations (r=?0.74, p<0.001), but not oxygen saturation. CC and MLO views were correlated for individual subjects and demonstrated no statistically significant differences in grouped analysis. Comparison of compressed and uncompressed imaging demonstrated a significant decrease in oxygen saturation under compression (58% versus 50%, p=0.04). Mammographic breast density categorization was correlated with measured optically derived properties.

Multiobjective guided priors improve the accuracy of near-infrared spectral tomography for breast imaging.

An image reconstruction regularization approach for magnetic resonance imaging-guided near-infrared spectral tomography has been developed to improve quantification of total hemoglobin (HbT) and water. By combining prior information from dynamic contrast enhanced (DCE) and diffusion weighted (DW) MR images, the absolute bias errors of HbT and water in the tumor were reduced by 22% and 18%, 21% and 6%, and 10% and 11%, compared to that in the no-prior, DCE- or DW-guided reconstructed images in three-dimensional simulations, respectively. In addition, the apparent contrast values of HbT and water were increased in patient image reconstruction from 1.4 and 1.4 (DCE) or 1.8 and 1.4 (DW) to 4.6 and 1.6.

Portable, parallel 9-wavelength near-infrared spectral tomography (NIRST) system for efficient characterization of breast cancer within the clinical oncology infusion suite.

A portable near-infrared spectral tomography (NIRST) system was developed with simultaneous frequency domain (FD) and continuous-wave (CW) optical measurements for efficient characterization of breast cancer in a clinical oncology setting. Simultaneous FD and CW recordings were implemented to speed up acquisition to 3 minutes for all 9 wavelengths, spanning a range from 661nm to 1064nm. An adjustable interface was designed to fit various breast sizes and shapes. Spatial images of oxy- and deoxy-hemoglobin, water, lipid, and scattering components were reconstructed using a 2D FEM approach. The system was tested on a group of 10 normal subjects, who were examined bilaterally and the recovered optical images were compared to radiographic breast density. Significantly higher total hemoglobin and water were estimated in the high density relative to low density groups. One patient with invasive ductal carcinoma was also examined and the cancer region was characterized as having a contrast ratio of 1.4 in total hemoglobin and 1.2 in water.

Calibration and optimization of 3D digital breast tomosynthesis guided near infrared spectral tomography.

Calibration of a three-dimensional multimodal digital breast tomosynthesis (DBT) x-ray and non-fiber based near infrared spectral tomography (NIRST) system is challenging but essential for clinical studies. Phantom imaging results yielded linear contrast recovery of total hemoglobin (HbT) concentration for cylindrical inclusions of 15 mm, 10 mm and 7 mm with a 3.5% decrease in the HbT estimate for each 1 cm increase in inclusion depth. A clinical exam of a patient's breast containing both benign and malignant lesions was successfully imaged, with greater HbT was found in the malignancy relative to the benign abnormality and fibroglandular regions (11 μM vs. 9.5 μM). Tools developed improved imaging system characterization and optimization of signal quality, which will ultimately improve patient selection and subsequent clinical trial results.

MR-Guided Near-Infrared Spectral Tomography Increases Diagnostic Performance of Breast MRI.

The purpose of this study was to determine the diagnostically most important molecular biomarkers quantified by magnetic resonance-guided (MR) near-infrared spectral tomography (NIRST) that distinguish malignant breast lesions from benign abnormalities when combined with outcomes from clinical breast MRI. The study was HIPAA compliant and approved by the Dartmouth Institutional Review Board, the NIH, the United States State Department, and Xijing Hospital. MR-guided NIRST evaluated hemoglobin, water, and lipid content in regions of interest defined by concurrent dynamic contrast-enhanced MRI (DCE-MRI) in the breast. MRI plus NIRST was performed in 44 subjects (median age, 46, age range, 20-81 years), 28 of whom had subsequent malignant pathologic diagnoses, and 16 had benign conditions. A subset of 30 subject examinations yielded optical data that met minimum sensitivity requirements to the suspicious lesion and were included in the analyses of diagnostic performance. In the subset of 30 subject examinations meeting minimum optical data sensitivity criterion, the MR-guided NIRST separated malignant from benign lesions using total hemoglobin (HbT; P < 0.01) and tissue optical index (TOI; P < 0.001). Combined MRI plus TOI data caused one false positive and 1 false negative, and produced the best diagnostic performance, yielding an AUC of 0.95, sensitivity of 95%, specificity of 89%, positive predictive value of 95%, and negative predictive value of 89%, respectively. MRI plus NIRST results correlated well with histopathologic diagnoses and could provide additional information to reduce the number of MRI-directed biopsies.