Quantitative Analysis of BrainAge using Neuroimaging Data to Estimate Radiation-Induced Brain Aging and Associations with Cognitive Changes in Brain Metastases Patients

PURPOSE/OBJECTIVE(S)

Radiotherapy is critical in brain tumor management yet causes accelerated aging via irreparable damage to white matter, cortex, and subcortical areas. BrainAGE is an open-source machine learning tool that analyses morphology from raw quantitative structural MRI to generate a predictive 'BrainAge' value, enabling analyses of patients with neurodegenerative diseases. We assessed the utility of this algorithm in measuring brain age morphology in brain metastases patients on a clinical trial, analyzed differences in BrainAge and chronological age, and explored associations with cognitive performance.

MATERIALS/METHODS

We analyzed pre-SRS high-resolution T1-weighted noncontrast volumetric MRI in patients with brain metastases (n = 57, median age 63 years, range 20-87) treated on a prospective clinical trial of cognitive-sparing SRS. The BrainAGE machine learning tool processed images to derive a BrainAge; it reliably generates this value using a Gaussian Processes regression, with a robust neurotypical training cohort. We examined correlations between BrainAge and chronological age with regression. Brain-predicted age gap (Brain-Gap) was calculated, defined as the difference between a patient's BrainAge and chronological age. We assessed cognitive function at baseline pre-SRS with a comprehensive battery of validated tests across multiple domains performed by a neuropsychologist, including memory (HVLT total), executive function (COWAT category fluency), and language (COWAT letter fluency). Raw test scores were scaled to T-scores adjusting for age, sex, and education level per testing norms. We examined if Brain-Gap was associated with cognitive performance pre-SRS.

RESULTS

BrainAGE software was robust, estimating a BrainAge for all input MRI sequences. We found a strong correlation between BrainAge and chronological age (r-squared = 0.82). The Brain-Gap median value was 0.84 and the mean was -0.90, in years (range -18.30-11.36 years). Brain-Gap was not significantly associated with cognitive performance across the three tests at the pre-SRS timepoint. Among patients with impaired cognition (T<35), there was no significant difference in BrainAge relative to chronological age.

CONCLUSION

To our knowledge, this is the first study utilizing the BrainAGE model as a biomarker of neuroanatomical age for brain tumors patients. Existing publications had lesion-free cohorts. Our results show that BrainAge was reliably associated with chronologic age in brain metastases patients pre-SRS. The Brain-Gap difference was minimal at baseline, and we found no significant association with pre-SRS cognitive performance. Future studies will examine this biomarker after SRS to look for individual aging radiation effects and prediction for cognitive changes after therapy.

Results From a Multi-Institutional Pilot Study of iContour, an Interactive Online Platform with Real-Time Feedback to Improve Contouring Education for Radiation Oncology Residents

PURPOSE/OBJECTIVE(S)

Numerous studies have shown that variability in contouring by radiation oncologists is common and associated with poor clinical outcomes. Contouring is taught via an apprenticeship model during residency with inconsistent results. Currently, there is no standardized contouring curriculum. We hypothesized that an interactive online educational platform for learners to practice contouring and receive real-time visual feedback would be a useful curricular tool.

MATERIALS/METHODS

The iContour platform displays anonymized DICOM data and allows for input and analysis of user contours in a web-based interface. Nine cases are available from the Head/Neck (H+N), Gynecologic (Gyn), and Gastrointestinal (GI) disease sites. The system presents users with a case and asks them to contour representative slices from 2-3 target volumes or OARs. Upon submission, users are shown several forms of feedback. These include immediate visual comparison with expert contours on the same dataset (all cases), customized feedback based on overlap with prespecified "avoidance" and "inclusion" structures that highlight common mistakes (Gyn cases), and tumor control probability models to estimate the clinical impact of a user's contour variations on patient outcomes (H+N cases). Some cases include short videos outlining anatomy and contouring principles which are shown before the user contours. A pilot study was performed to evaluate technical performance and educational utility. Pre- and post-surveys with Likert-type questions (1-5 scale from strongly disagree to strongly agree) were used to assess user satisfaction and preferences regarding feedback.

RESULTS

A total of 9 residents participated (median PGY3, range PGY2-5) from 5 institutions in 2 countries. Each participant completed 2 cases from a single disease site (n = 3 each for H+N, Gyn and GI), one with educational videos and one without. 67% of users had completed a prior clinical rotation in their disease site. Overall, residents felt the system was a useful educational tool (mean Likert score 4.67 +/- 0.47) and were interested in using it during clinical rotations (4.89 +/- 0.31). Most participants (7/9) felt iContour was more useful than existing resources for contouring education. Residents unanimously (9/9) found direct visual comparison with expert contours the most useful type of feedback, and that cases with videos before contouring were more educational.

CONCLUSION

The iContour platform is a useful educational tool for radiation oncology residents. Participants felt receiving immediate visual feedback on contours was a valuable learning experience. Short instructional videos before contouring can be utilized to provide "just in time" teaching. A randomized study to formally assess the platform's impact on contouring skills is planned.

Translating the Biology of Aging into New Therapeutics for Alzheimer's Disease: Senolytics

The recent FDA-approval for amyloid lowering therapies reflects an unwavering commitment from the Alzheimer's disease (AD) research community to identify treatments for this leading cause of dementia. The clinical benefits achieved by reducing amyloid, though modest, provide evidence that disease modification is possible. Expanding the same tenacity to interventions targeting upstream drivers of AD pathogenesis could significantly impact the disease course. Advanced age is the greatest risk factor for developing AD. Interventions targeting biological aging offer the possibility of disrupting a foundational cause of AD. Senescent cells accumulate with age and contribute to inflammation and age-related diseases like AD. Senolytic drugs that clear senescent cells improve healthy aging, halt AD disease progression in animal models and are undergoing clinical testing. This review explores the biology of aging, the role of senescent cells in AD pathology, and various senotherapeutic approaches such as senolytics, dampening the SASP (senescence associated secretory phenotype), senescence pathway inhibition, vaccines, and prodrugs. We highlight ongoing clinical trials evaluating the safety and efficacy of the most advanced senolytic approach, dasatinib and quercetin (D+Q), including an ongoing Phase II senolytic trial supported by the Alzheimer's Drug Discovery Foundation (ADDF). Challenges in the field of senotherapy for AD, including target engagement and biomarker development, are addressed. Ultimately, this research pursuit may lead to an effective treatment for AD and provide the field with another disease-modifying therapy to be used, alone or in combination, with other emerging treatment options.

High tech home care: surviving and prospering in a changing environment

Managed care plans are expanding rapidly into new marketplaces. Reimbursement for home infusion therapy, including parenteral and enteral nutrition, is significantly affected under managed care, especially when capitated payment mechanisms are used. Home care companies have experienced downsizing, mergers, acquisitions, and fierce competition in the managed care environment. Clinicians who are entering the home care setting may find that, in addition to clinical expertise, their marketability depends on a set of new skills and abilities in order to prosper in this new environment.

Issues in the management of percutaneous central venous catheters. Single and multiple lumens

In this era of high technology and extensive parenteral therapies, multiple-lumen CVCs seem to be among the many devices needed to provide appropriate care to hospitalized patients. All CVCs, regardless of their benefit, create substantial risks for mechanical and septic complications. Antibacterial solutions that are bonded to the catheter and longer-acting skin antiseptics offer preliminary evidence that CVC sepsis rates can be reduced. The advances in CVC design, materials, and coatings are intended to be a supplement to--not a substitute for--meticulous care of CVCs.

Vascular access devices: perspectives on designs, complications, and management

The use of vascular access devices in hospitalized and home care patients has expanded rapidly in the past decade. New designs, materials, insertion techniques, and protocols for care related to vascular access devices have emerged. Complications associated with them, however, have remained a persistent problem. Septicemia, thrombosis, and occlusion are three of the more serious complications that can lead to the need for removal of the device. These complications are reviewed and areas for future research are identified.

Nutritional support in home care

Nutritional support was among the first of the high-tech therapies to make the transition from hospital to home. Growth in high-tech home care accelerated in the mid-1980s, following establishment of the prospective payment system. Rapid growth in home care continues amid acquisitions and mergers of home care companies. The HPN and HEN populations have both enlarged and evolved with time, and the current populations mirror changes in health care demographics--showing the largest increases in services to the elderly. Changes have occurred in the types of venous and enteral access devices, infusion systems, parenteral and enteral products, and infusion schedules used by HPN and HEN patients. As therapies have caused less disruption in patients' lifestyles and as services have become more widely available, adaptation to HPN and HEN has become somewhat less difficult. However, patients still report concerns over finances, respite services, and symptoms management. Nurses have a primary role in the preparation of patients for home nutritional support and in the provision of home care services. Nursing research can illuminate the unique contribution of nurses to safe, cost effective, and high quality home nutritional support.