Bi-parametric MRI (bpMRI: T2W MRI and Apparent Diffusion Coefficient maps (ADC) derived from diffusion weighted imaging) is increasingly being used to characterize prostate cancer (PCa). However, inter- and intrareader variability hinders interpretation of MRI. Deep learning networks may aid in PCa characterization and may allow for non-invasively distinguishing clinically significant (csPCa: GGG<1) and insignificant (ciPCa: GGG=1) PCa. Recent studies have shown that signatures from peri-tumoral (PT) region on imaging add significant value to those from intra-tumoral (IT) region for disease detection and characterization. In this work, we present a multi-sequence multi-instance learning convolutional neural network trained using 2D patches extracted from PCa regions of interest (ROIs) on prostate bpMRI to distinguish csPCa and ciPCa. The trained classifier is used to extract pooled features from both the IT and PT ROIs, which are then used to train a random forest classifier to distinguish csPCa and ciPCa. We train and test our models using patient studies from two different institutions (n=298) with GGG obtained either from post-surgical specimens or biopsies. Model built using IT (DIT) and PT (DPT) deep features alone resulted in an area under the curve (AUC) of 0.83 and 0.73 respectively, while models computed from IT (RIT) and PT (RPT) radiomic features resulted in an AUC of 0.77 and 0.75 respectively. The models DIP and RIP trained on combination of IT and PT deep features and radiomic features resulted in an AUC of 0.86 and 0.80 respectively. In both cases, we observe that combining IT and PT features helps in improving the overall classifier performance in distinguishing csPCa and ciPCa.
The presence of tumor-infiltrating lymphocytes (TILs) is correlated with outcome and prognosis in epithelial ovarian cancer (EOC). In this study, automated image analysis was used to analyze the association between overall survival (OS) and TIL spatial arrangement and density in a multi-site cohort of 102 EOC patients who received adjuvant chemotherapy following debulking surgery. Features of the spatial arrangement of TILs (SpaTIL) were used to quantify the spatial co-localization of TILs and tumor cells on digitized pathology slides of the malignant neoplasm of excised specimens. A multivariable Cox regression model of SpaTIL features was fit on the n1 = 51 patient training set and was evaluated in the n2 = 51 patient validation set. The SpaTIL signature was significantly associated with OS, both in the training set (hazard ratio (HR) = 2.81, 95% confidence interval (CI) = 1.33 − 5.92, and p = 0.003) and the validation set (HR = 2.06, 95% CI = 1.04 − 4.07, and p = 0.008). In addition, fusing our spaTIL risk score and the clinical staging further improved the results of the predictive model (HR = 4.045, 95% CI = 4.11−5.41, and p = 0.0002 in the validation set) and outperformed clinical staging alone. This finding illustrates that a spaTIL risk score is not only able to predict OS independent of clinical data, but also offers prognostic value complementary to current clinical standard-of-care. Patients with longer survival times had significantly higher heterogeneity of non-TIL cluster area, while shorter time survivors had mostly same-sized, evenly-distributed non-TIL clusters and smaller average TIL cluster area. These findings suggest that dispersion of TILs throughout the tumor is associated with better treatment response to post-treatment adjuvant chemotherapy, and therefore longer survival time.
Allogenic hematopoietic stem cell transplant (HCT) is a curative therapy for acute myeloid leukemia (AML). Relapse after HCT is the most common cause of treatment failure and is associated with poor prognosis. Early identification of which patients are at elevated risk of relapse may justify use of aggressive post-HCT treatment options, potentially preventing relapse and treatment failure. In this study, our goal was to predict relapse after HCT in AML patients using quantitative features extracted from digitized Wright-Giemsa stained posttransplant aspirate smears. We collected 39 aspirate specimens from a cohort of 39 AML patients after HCT, of which 25 experienced relapse, while 14 did not. Our approach comprised the following main steps. First, a deep learning model was developed to segment myeloblasts, a cell type in bone marrow that accumulates and characterizes AML. A total of 161 texture and shape descriptors were then extracted from these segmented myeloblasts. The top eight predictive features were identified using a Wilcoxon rank sum test over 100 iterations of 3-fold cross validation. A model was subsequently built employing these features and yielded an average area under the receiver operating characteristic curve of 0.80±0.05 in cross validation. The top eight features include four Haralick texture features and four fractal dimension features. The texture features appear to characterize chromatin patterns in myeloblasts while the fractal features quantify morphological irregularity and complexity of myeloblasts, in alignment with findings previously reported for AML patients post-treatment.
Diabetic macular edema is a leading cause of vision loss in diabetic patients. The underlying cause for the onset of DME is 1) the long term presence of hyperglycemia and the eventual degradation of the blood-retinal barrier (BRB) via an uptick in vascular endothelial growth factor (VEGF); VEGF increases the permeability of the blood retinal barrier and alters the length of capillaries, thereby inhibiting the ability of these vessels in performing their primary function of filtration. The lack of a proper filtration system in combination with the ongoing change in intra-retinal vasculature that stems from it, results in the eventual loss of visual acuity in DME patients. Due to the large role in which VEGF plays in acting as a catalyst for the onset of DME, current treatments now focus on utilizing anti-VEGF therapy as a first line treatment for DME. Anti-VEGF therapy improves clinical outcomes in the form of improved visual acuity and reduction in macular edema. Anti-VEGF treatments also have a peripheral effect of modifying the disease burden and allowing for extended time in between treatments. However, there is still a void in understanding how anti-VEGF affects the underlying pathophysiology. This study focuses on using quantification of the geometric properties of vasculature on Fluorescein Angiography(FA) to understand the impact anti-VEGF treatment has on retinal vascular dynamics. We hypothesize that vasculature disorder, due to VEGF action, differs across patients and can be modeled mathematically to identify candidates for anti-VEGF treatment. We use VaNgOGH, a Hough transform-based descriptor to model the disorder of the retinal vascular network on baseline FA of patients subsequently treated with intravitreal anti-VEGF therapy (aibercept). VaNgOGH computes local measures of vessel-curvature and identifies dominant peaks in the accumulator space. We explored the differences in such features on baseline FA between eyes tolerating extended dosing interval (N=15) and those eyes requiring more frequent dosing (N=12), based on initial response following treatment interval extension. The cross-validated AUC was found to be 0.73±0.1 using VaNgOGH. The variance of local orientations showed a statistically significant difference (p=0.008) between the two categories, unlike clinical parameters on baseline OCT. Our results suggest there may be fundamental differences in localized vessel orientations between eyes that will exhibit favorable response to extended interval aibercept dosing and eyes that require more frequent dosing.
Neoadjuvant chemotherapy (NAC) is routinely used to treat breast tumors before surgery to reduce tumor size and improve outcome. However, no current clinical or imaging metrics can effectively predict before treatment which NAC recipients will achieve pathological complete response (pCR), the absence of residual invasive disease in the breast or lymph nodes following surgical resection. In this work, we developed and applied a convolu- tional neural network (CNN) to predict pCR from pre-treatment dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) scans on a per-voxel basis. In this study, DCE-MRI data for a total of 166 breast cancer pa- tients from the ISPY1 Clinical Trial were split into a training set of 133 patients and a testing set of 33 patients. A CNN consisting of 6 convolutional blocks was trained over 30 epochs. The pre-contrast and post-contrast DCE-MRI phases were considered in isolation and conjunction. A CNN utilizing a combination of both pre- and post-contrast images best distinguished responders, with an AUC of 0.77; 82% of the patients in the testing set were correctly classified based on their treatment response. Within the testing set, the CNN was able to produce probability heatmaps that visualized tumor regions that most strongly predicted therapeutic response. Multi- variate analysis with prognostic clinical variables (age, largest diameter, hormone receptor and HER2 status), revealed that the network was an independent predictor of response (p=0.05), and that the inclusion of HER2 status could further improve capability to predict response (AUC = 0.85, accuracy = 85%).
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