Purpose Morphological changes to anatomy resulting from invasive surgical procedures or pathology, typically alter the surrounding vasculature. This makes it useful as a descriptor for feature... Show morePurpose Morphological changes to anatomy resulting from invasive surgical procedures or pathology, typically alter the surrounding vasculature. This makes it useful as a descriptor for feature-driven image registration in various clinical applications. However, registration of vasculature remains challenging, as vessels often differ in size and shape, and may even miss branches, due to surgical interventions or pathological changes. Furthermore, existing vessel registration methods are typically designed for a specific application. To address this limitation, we propose a generic vessel registration approach useful for a variety of clinical applications, involving different anatomical regions. Methods A probabilistic registration framework based on a hybrid mixture model, with a refinement mechanism to identify missing branches (denoted as HdMM+) during vasculature matching, is introduced. Vascular structures are represented as 6-dimensional hybrid point sets comprising spatial positions and centerline orientations, using Student's t-distributions to model the former and Watson distributions for the latter. Results The proposed framework is evaluated for intraoperative brain shift compensation, and monitoring changes in pulmonary vasculature resulting from chronic lung disease. Registration accuracy is validated using both synthetic and patient data. Our results demonstrate, HdMM+ is able to reduce more than 85% of the initial error for both applications, and outperforms the state-of-the-art point-based registration methods such as coherent point drift and Student's t-distribution mixture model, in terms of mean surface distance, modified Hausdorff distance, Dice and Jaccard scores. Conclusion The proposed registration framework models complex vascular structures using a hybrid representation of vessel centerlines, and accommodates intricate variations in vascular morphology. Furthermore, it is generic and flexible in its design, enabling its use in a variety of clinical applications. Show less
Background: The potential survival benefits of adding radiotherapy to systemic therapy for esophageal cancer patients with oligometastases are unknown.Methods: In this retrospective analysis,... Show moreBackground: The potential survival benefits of adding radiotherapy to systemic therapy for esophageal cancer patients with oligometastases are unknown.Methods: In this retrospective analysis, patients with stage IV esophageal cancer (according to the American Joint Committee on Cancer Seventh edition staging system) with <= 3 metastases who underwent chemotherapy with cisplatin/paclitaxel between 2012 and 2015 were identified. Patients received chemotherapy (CT) alone vs. concurrent chemoradiotherapy (CCRT) to all metastases.Results: Of 461 patients, 97% had squamous cell cancer. One hundred and ninety-six patients (42.5%) received CCRT and 265 (57.5%) underwent CT alone. At week 8, there were 3 (1.5%) complete responses (CR) and 95 (48.5%) partial responses (PR) in the CCRT group, compared to 3 (1.1%) CR and 102 (38.5%) PR in the CT alone group. The overall rate of improvement in dysphagia score was noted in 78.5% of patients in the CCRT group versus 61.5% in the CT alone group (P=0.014). A statistically significant difference was demonstrated in disease control rate between the two groups (81.6% vs. 64.5%, P<0.001). Patients who underwent CCRT had superior median PFS and a trend toward longer median OS compared to those receiving CT alone (8.7 vs. 7.3 months, P=0.002 and 16.8 vs. 14.8 months, P=0.056, respectively). The median OS was 19.3 months in patients who achieved CR/PR, compared to 14.9 months and 9.6 months for patients who had stable disease and progressive disease, respectively (P<0.001).Conclusions: Compared to chemotherapy alone, chemoradiation to all sites in patients with esophageal cancer with <= 3 metastases may lead to a modest increase in PFS and a trend toward longer OS. Further investigation of optimal integration of radiotherapy and chemotherapy in these patients is warranted. Show less
