Matching Disparate Image Pairs Using Shape-Aware ConvNets

An end-to-end trainable ConvNet architecture, that learns to harness the power of shape representation for matching disparate image pairs, is proposed. Disparate image pairs are deemed those that exhibit strong affine variations in scale, viewpoint and projection parameters accompanied by the presence of partial or complete occlusion of objects and extreme variations in ambient illumination. Under these challenging conditions, neither local nor global feature-based image matching methods, when used in isolation, have been observed to be effective. The proposed correspondence determination scheme for matching disparate images exploits high-level shape cues that are derived from low-level local feature descriptors, thus combining the best of both worlds. A graph-based representation for the disparate image pair is generated by constructing an affinity matrix that embeds the distances between feature points in two images, thus modeling the correspondence determination problem as one of graph matching. The eigenspectrum of the affinity matrix, i.e., the learned global shape representation, is then used to further regress the transformation or homography that defines the correspondence between the source image and target image. The proposed scheme is shown to yield state-of-the-art results for both, coarse-level shape matching as well as fine point-wise correspondence determination.Comment: First two authors contributed equally, to Appear in the IEEE Winter Conference on Applications of Computer Vision (WACV) 201

Localized Multifocal Retroperitoneal Ganglioneuroma with an Infiltrative Appearance on Imaging: A Case Report

Multifocal ganglioneuromas are characterized by the presence of multiple benign neuroepithelial tumor nodules and are less common than solitary tumors. A small percentage of ganglioneuromas present with a fatty appearance. Only a few cases of multifocal ganglioneuromas have been reported, due to both their rarity and minimal symptomatic presentation; therefore, generalizations about risk factors and predictive markers are very difficult. Here, we report a case of multifocal retroperitoneal ganglioneuroma with an infiltrative appearance on computed tomography (CT). The tumor demonstrated slow growth on multiple imaging studies and was associated with abdominal and flank pain. The aggressive appearance eventually led to surgical resection 18 months after the initial incidental finding on CT. Postsurgical analysis of the tumor on imaging was crucial in revealing its nodularity and infiltration, as well as for clarifying its retroperitoneal location inseparable from the adrenal gland. Histology demonstrated Schwann cells and ganglion cells without atypia or increased cellularity, and with no mitosis or necrosis seen. Our case highlights the consideration of ganglioneuroma with fatty infiltration in the differential diagnosis of a fatty tumor in the mediastinum or retroperitoneum. Additionally, our report differentiates multifocal ganglioneuroma with fatty infiltration from lipomatous ganglioneuroma on radiology and histopathology

Impact of margin status and lymphadenectomy on clinical outcomes in resected pancreatic adenocarcinoma: implications for adjuvant radiotherapy.

BackgroundAdjuvant chemoradiotherapy (CRT) in the treatment of pancreatic ductal adenocarcinoma (PDA) is controversial. Minimal data exists regarding the clinical significance of margin clearance distance and lymph node (LN) parameters, such as extent of dissection and LN ratio. We assessed the impact of these variables on clinical outcomes to more clearly define the subset of patients who may benefit from adjuvant radiotherapy (RT).MethodsWe identified 106 patients with resected stage 1-3 PDA from 2007-2013. Resection margins were categorized as positive (tumor at ink), ≤1, or >1 mm. LN evaluation included total number examined (NE), number of positive nodes (NP), ratio of NP to NE (NR), extent of dissection, and positive periportal LNs. The impact of these variables was assessed on disease-free survival (DFS) and overall survival (OS) using multivariate cox proportional hazards modeling.ResultsIn patients receiving adjuvant chemotherapy (CT) alone, greater margin clearance led to improved DFS (P=0.0412, HR =0.51). Range of NE was 4-37, with a mean of 19. NE was not associated with DFS or OS, yet absolute NP of 5 or more was associated with a significantly worse DFS (P=0.005). Whereas periportal lymphadenectomy did not result in improved DFS or OS, patients with positive periportal LN had worse clinical outcomes (DFS, P=0.0052; OS, P=0.023). The use of adjuvant CRT was associated with improved OS (P=0.049; HR=0.29).ConclusionsIn patients receiving adjuvant CT alone, there was a clinically significant benefit to clearing the surgical margin beyond tumor at ink. Having ≥5 NP and positive periportal LN led to significantly worse clinical outcomes. The addition of adjuvant RT to CT in resected PDA improved OS. A comprehensive evaluation of resection margin distance and LN parameters may identify more patients at risk for locoregional failure who may benefit from adjuvant CRT

Liver Transplantation in Patients with Sickle Cell Disease in the United States

Background: Up to 30% of patients with sickle cell disease (SCD) develop chronic liver disease via etiologies including sickle cell hepatopathy, acquired viral hepatitis, or secondary hemochromatosis. It is unclear how many patients with SCD ultimately undergo liver transplantation (LT) and what factors are associated with survival after LT. In this study, we examined LT outcomes in these patients by reviewing the Scientific Registry of Transplant Recipients (SRTR) and our institutional experience. Methods: Analysis of the SRTR identified 23 LT recipients and five simultaneous liver and kidney transplantation (SLKT) recipients with SCD. Patient demographics and graft and patient survival were analyzed. Two patients with SCD at our institution underwent SLKT. Results: Review of the SRTR revealed that recipients with SCD had significantly higher model for end-stage liver disease scores (33 versus 21, P = 0.004), preoperative intensive care unit admission (43.5% versus 19.1%, P = 0.007), preoperative dialysis (17.4% versus 4.9%, P = 0.009), and were more likely to be status 1 (26.1% versus 12.1%, P = 0.041) when compared with the reference population of African American LT recipients. Despite being higher risk at the time of LT, patients with SCD had equivalent posttransplant graft and patient survival when compared with the reference population (P = 0.5 and P = 0.2, respectively) and a 2:1 propensity score–matched group (P = 0.5 and P = 0.2, respectively). Two recent SLKT recipients with SCD from our institution have performed well with stable allograft function. Conclusions: Data from the SRTR demonstrate that patients with SCD can expect equivalent graft and patient survival after LT despite exhibiting more comorbidities at the time of LT. The low number of patients with SCD who underwent LT in the SRTR in comparison with the rate of chronic liver disease in this population raises the question as to whether a disparity in access to LT exists for this complex population

Liver Transplantation in Patients with Sickle Cell Disease in the United States

Background: Up to 30% of patients with sickle cell disease (SCD) develop chronic liver disease via etiologies including sickle cell hepatopathy, acquired viral hepatitis, or secondary hemochromatosis. It is unclear how many patients with SCD ultimately undergo liver transplantation (LT) and what factors are associated with survival after LT. In this study, we examined LT outcomes in these patients by reviewing the Scientific Registry of Transplant Recipients (SRTR) and our institutional experience. Methods: Analysis of the SRTR identified 23 LT recipients and five simultaneous liver and kidney transplantation (SLKT) recipients with SCD. Patient demographics and graft and patient survival were analyzed. Two patients with SCD at our institution underwent SLKT. Results: Review of the SRTR revealed that recipients with SCD had significantly higher model for end-stage liver disease scores (33 versus 21, P = 0.004), preoperative intensive care unit admission (43.5% versus 19.1%, P = 0.007), preoperative dialysis (17.4% versus 4.9%, P = 0.009), and were more likely to be status 1 (26.1% versus 12.1%, P = 0.041) when compared with the reference population of African American LT recipients. Despite being higher risk at the time of LT, patients with SCD had equivalent posttransplant graft and patient survival when compared with the reference population (P = 0.5 and P = 0.2, respectively) and a 2:1 propensity score–matched group (P = 0.5 and P = 0.2, respectively). Two recent SLKT recipients with SCD from our institution have performed well with stable allograft function. Conclusions: Data from the SRTR demonstrate that patients with SCD can expect equivalent graft and patient survival after LT despite exhibiting more comorbidities at the time of LT. The low number of patients with SCD who underwent LT in the SRTR in comparison with the rate of chronic liver disease in this population raises the question as to whether a disparity in access to LT exists for this complex population

Technical optimization of spatially resolved single-cell transcriptomic datasets to study clinical liver disease

Abstract Single cell and spatially resolved ‘omic’ techniques have enabled deep characterization of clinical pathologies that remain poorly understood, providing unprecedented insights into molecular mechanisms of disease. However, transcriptomic platforms are costly, limiting sample size, which increases the possibility of pre-analytical variables such as tissue processing and storage procedures impacting RNA quality and downstream analyses. Furthermore, spatial transcriptomics have not yet reached single cell resolution, leading to the development of multiple deconvolution methods to predict individual cell types within each transcriptome ‘spot’ on tissue sections. In this study, we performed spatial transcriptomics and single nucleus RNA sequencing (snRNAseq) on matched specimens from patients with either histologically normal or advanced fibrosis to establish important aspects of tissue handling, data processing, and downstream analyses of biobanked liver samples. We observed that tissue preservation technique impacts transcriptomic data, especially in fibrotic liver. Single cell mapping of the spatial transcriptome using paired snRNAseq data generated a spatially resolved, single cell dataset with 24 unique liver cell phenotypes. We determined that cell–cell interactions predicted using ligand–receptor analysis of snRNAseq data poorly correlated with cellular relationships identified using spatial transcriptomics. Our study provides a framework for generating spatially resolved, single cell datasets to study gene expression and cell–cell interactions in biobanked clinical samples with advanced liver disease