Increasing the efficiency of cone-beam CT based delta-radiomics using automated contours to predict radiotherapy-related toxicities in prostate cancer.

Extracting longitudinal image quantitative data, known as delta-radiomics, has the potential to capture changes in a patient's anatomy throughout the course of radiation treatment for prostate cancer. Some of the major challenges of delta-radiomics studies are contouring the structures for individual fractions and accruing patients' data in an efficient manner. The manual contouring process is often time consuming and would limit the efficiency of accruing larger sample sizes for future studies. The problem is amplified because the contours are often made by highly trained radiation oncologists with limited time to dedicate to research studies of this nature. This work compares the use of automated prostate contours generated using a deformable image-based algorithm to make predictive models of genitourinary and changes in total international prostate symptom score in comparison to manually contours for a cohort of fifty patients. Area under the curve of manual and automated models were compared using the Delong test. This study demonstrated that the delta-radiomics models were similar for both automated and manual delta-radiomics models.

Uncovering prostate cancer aggressiveness signal in T2-weighted MRI through a three-reference tissues normalization technique.

Quantitative T2-weighted MRI (T2W) interpretation is impeded by the variability of acquisition-related features, such as field strength, coil type, signal amplification, and pulse sequence parameters. The main purpose of this work is to develop an automated method for prostate T2W intensity normalization. The procedure includes the following: (i) a deep learning-based network utilizing MASK R-CNN for automatic segmentation of three reference tissues: gluteus maximus muscle, femur, and bladder; (ii) fitting a spline function between average intensities in these structures and reference values; and (iii) using the function to transform all T2W intensities. The T2W distributions in the prostate cancer regions of interest (ROIs) and normal appearing prostate tissue (NAT) were compared before and after normalization using Student's t-test. The ROIs' T2W associations with the Gleason Score (GS), Decipher genomic score, and a three-tier prostate cancer risk were evaluated with Spearman's correlation coefficient (rS ). T2W differences in indolent and aggressive prostate cancer lesions were also assessed. The MASK R-CNN was trained with manual contours from 32 patients. The normalization procedure was applied to an independent MRI dataset from 83 patients. T2W differences between ROIs and NAT significantly increased after normalization. T2W intensities in 231 biopsy ROIs were significantly negatively correlated with GS (rS = -0.21, p = 0.001), Decipher (rS = -0.193, p = 0.003), and three-tier risk (rS = -0.235, p < 0.001). The average T2W intensities in the aggressive ROIs were significantly lower than in the indolent ROIs after normalization. In conclusion, the automated triple-reference tissue normalization method significantly improved the discrimination between prostate cancer and normal prostate tissue. In addition, the normalized T2W intensities of cancer exhibited a significant association with tumor aggressiveness. By improving the quantitative utilization of the T2W in the assessment of prostate cancer on MRI, the new normalization method represents an important advance over clinical protocols that do not include sequences for the measurement of T2 relaxation times.

Clinical-Genomic Risk Group Classification of Suspicious Lesions on Prostate Multiparametric-MRI.

The utilization of multi-parametric MRI (mpMRI) in clinical decisions regarding prostate cancer patients' management has recently increased. After biopsy, clinicians can assess risk using National Comprehensive Cancer Network (NCCN) risk stratification schema and commercially available genomic classifiers, such as Decipher. We built radiomics-based models to predict lesions/patients at low risk prior to biopsy based on an established three-tier clinical-genomic classification system. Radiomic features were extracted from regions of positive biopsies and Normally Appearing Tissues (NAT) on T2-weighted and Diffusion-weighted Imaging. Using only clinical information available prior to biopsy, five models for predicting low-risk lesions/patients were evaluated, based on: 1: Clinical variables; 2: Lesion-based radiomic features; 3: Lesion and NAT radiomics; 4: Clinical and lesion-based radiomics; and 5: Clinical, lesion and NAT radiomic features. Eighty-three mpMRI exams from 78 men were analyzed. Models 1 and 2 performed similarly (Area under the receiver operating characteristic curve were 0.835 and 0.838, respectively), but radiomics significantly improved the lesion-based performance of the model in a subset analysis of patients with a negative Digital Rectal Exam (DRE). Adding normal tissue radiomics significantly improved the performance in all cases. Similar patterns were observed on patient-level models. To the best of our knowledge, this is the first study to demonstrate that machine learning radiomics-based models can predict patients' risk using combined clinical-genomic classification.

Association of HIV and viral suppression status with hospital acute kidney injury in the era of antiretroviral therapy.

In the modern era, it is unknown if people that are virally suppressed with HIV (PWH) are at increased risk for acute kidney injury (AKI) compared to people without HIV and no studies have compared the risk of AKI by viral suppression status. Here, we determined the associations of HIV status and AKI among PWH with and without viral suppression compared to people without HIV. An observational cohort study of PWH and people without HIV hospitalized in a large New York City health system between 2010-2019 was conducted. Multivariable Cox proportional hazards models were used to determine associations between HIV status and risk of AKI, severe AKI and development of chronic kidney disease (CKD). Among 173,884 hospitalized patients, 4,718 had HIV; 2,532 (53.7%) were virally suppressed and 2,186 (46.3%) were not suppressed. Compared to people without HIV, PWH with and without viral suppression were at increased risk of AKI (adjusted hazard ratio 1.27, 95% confidence interval 1.15, 1.40 and 1.73, 1.58, 1.90, respectively) and AKI requiring kidney replacement therapy (1.89, 1.27, 2.84 and 1.87, 1.23, 2.84, respectively). Incremental, graded associations were observed between HIV status and Stage 2 or 3 AKI, and among AKI survivors, and incident CKD. The elevated risk of AKI across ages of PWH was similar in magnitude to older people without HIV. Thus, regardless of virologic control, HIV is an independent risk factor for AKI among hospitalized patients. Future studies should determine the mechanisms by which HIV increases susceptibility to AKI and identify strategies to prevent AKI in PWH.

Metabolic acidosis in pediatric kidney transplant recipients.

BACKGROUND: Metabolic acidosis is a risk factor for faster kidney function decline in chronic kidney disease (CKD) and in adult kidney transplant recipients (KTRs). We hypothesized that metabolic acidosis would be highly prevalent and associated with worse allograft function in pediatric KTRs. METHODS: Pediatric KTRs at Montefiore Medical Center from 2010 to 2018 were included. Metabolic acidosis was defined as serum bicarbonate < 22 mEq/L or receiving alkali therapy. Regression models were adjusted for demographic factors and donor/recipient characteristics. RESULTS: Sixty-three patients were identified with a median age at transplant of 10.5 (interquartile range (IQR) 4.4-15.2) years and post-transplant follow-up of 3 (IQR 1-5) years. Baseline serum bicarbonate was 21.7 ± 2.4 mEq/L, serum bicarbonate < 22 mEq/L was present in 28 (44%), and 44% of all patients were receiving alkali therapy. The prevalence of acidosis ranged from 58 to 70% during the first year of follow-up. At baseline, each 1-year higher age at transplant and every 10 ml/min/1.73 m2 higher eGFR were associated with 0.16 mEq/L (95% CI: 0.03-0.3) and 0.24 mEq/L (95% CI: 0.01-0.5) higher serum bicarbonate, respectively. Older age at transplant was associated with lower odds of acidosis (OR: 0.84; 95% CI: 0.72-0.97). During follow-up, metabolic acidosis was independently associated with 8.2 ml/min/1.73 m2 (95% CI 4.4-12) lower eGFR compared to not having acidosis; furthermore, eGFR was significantly lower among KTRs with unresolved acidosis compared with resolved acidosis. CONCLUSIONS: Among pediatric KTRs, metabolic acidosis was highly prevalent in the first year post-transplantation and was associated with lower eGFR during follow-up. A higher resolution version of the Graphical abstract is available as Supplementary information.

Association of Dietary Potassium Intake With Abdominal Aortic Calcification and Pulse Pressure in US Adults.

OBJECTIVES: Arterial calcification contributes to cardiovascular mortality. Based on a recent animal study, we hypothesized that higher dietary potassium intake was associated with less abdominal aortic calcification (AAC) and lower arterial stiffness among adults in the United States. METHODS: Cross-sectional analyses were performed on participants over 40 years old from the National Health and Nutrition Examination Survey 2013-2014. Dietary potassium intake was categorized into quartiles (Q1: <1911, Q2: 1911-2461, Q3: 2462-3119, and Q4: >3119 mg/d). Primary outcome AAC was quantified using the Kauppila scoring system. AAC scores were categorized into no AAC (AAC = 0, reference group), mild/moderate (AAC >0 to ≤ 6), and severe AAC (AAC >6). Pulse pressure was used as a surrogate for arterial stiffness and examined as a secondary outcome. RESULTS: Among 2,418 participants, there was not a linear association between dietary potassium intake and AAC. Higher dietary potassium intake was associated with less severe AAC when comparing dietary potassium intake in Q2 with Q1 (odds ratio 0.55; 95% confidence interval: 0.34 to 0.92; P = .03). Higher dietary potassium intake was significantly associated with lower pulse pressure (P = .007): per 1000 mg/d higher dietary potassium intake, pulse pressure was 1.47 mmHg lower in the fully adjusted model. Compared to participants with dietary potassium intake in Q1, pulse pressure was 2.84 mmHg lower in Q4 (P = .04). CONCLUSIONS: We did not find a linear association between dietary potassium intake and AAC. Dietary potassium intake was negatively associated with pulse pressure.

ED visits, hospital admissions and treatment breaks in head/neck cancer patients undergoing radiotherapy.

Objectives: Radiation therapy (RT) is an integral part of treatment of head/neck cancer (HNC) but is associated with many toxicities. We sought to evaluate sociodemographic, pathologic, and clinical factors associated with emergency department (ED) visits, hospital admissions (HA), and RT breaks in HNC patients undergoing curative-intent RT. Methods: We completed a Level 3 (Oxford criteria for evidence-based medicine) analysis of a cohort of HNC patients who underwent curative-intent RT at our institution from 2013 to 2017. We collected demographic characteristics and retrospectively assessed for heavy opioid use, ED visits or HA during RT as well as RT breaks. Treatment breaks were defined as total days to RT fractions ratio ≥1.6. Multivariable stepwise logistic regression analyses were done to determine the association of various sociodemographic, pathologic, and clinical characteristics with ED visits, HA and RT treatment breaks. Results: The cohort included 376 HNC patients (294 male, 82 female, median age 61). On multivariable analysis, significant factors associated with ED visits during RT were heavy opioid use and black race. Receipt of concomitant chemotherapy was the only factor associated with hospital admissions during RT. Advanced age, lower socioeconomic class, glandular site, and receipt of chemotherapy were all independently associated with RT breaks. Lower cancer stage and lack of substance abuse history were independently associated with lack of treatment breaks. Conclusion: HNC patients with factors such as heavy opioid use, Black race, receipt of concomitant chemotherapy, and lower socioeconomic class may require closer monitoring during RT.

Delineation of recurrent glioblastoma by whole brain spectroscopic magnetic resonance imaging.

BACKGROUND: Glioblastoma (GBM) cellularity correlates with whole brain spectroscopic MRI (sMRI) generated relative choline to N-Acetyl-Aspartate ratio (rChoNAA) mapping. In recurrent GBM (rGBM), tumor volume (TV) delineation is challenging and rChoNAA maps may assist with re-RT targeting. METHODS: Fourteen rGBM patients underwent sMRI in a prospective study. Whole brain sMRI was performed to generate rChoNAA maps. TVs were delineated by the union of rChoNAA ratio over 2 (rChoNAA > 2) on sMRI and T1PC. rChoNAA > 2 volumes were compared with multiparametric MRI sequences including T1PC, T2/FLAIR, diffusion-restriction on apparent diffusion coefficient (ADC) maps, and perfusion relative cerebral blood volume (rCBV). RESULTS: rChoNAA > 2 (mean 27.6 cc, range 6.6-79.1 cc) was different from other imaging modalities (P ≤ 0.05). Mean T1PC volumes were 10.7 cc (range 1.2-31.4 cc). The mean non-overlapping volume of rChoNAA > 2 and T1PC was 29.2 cm3. rChoNAA > 2 was 287% larger (range 23% smaller-873% larger) than T1PC. T2/FLAIR volumes (mean 111.7 cc, range 19.0-232.7 cc) were much larger than other modalities. rCBV volumes (mean 6.2 cc, range 0.2-19.1 cc) and ADC volumes were tiny (mean 0.8 cc, range 0-3.7 cc). Eight in-field failures were observed. Three patients failed outside T1PC but within rChoNAA > 2. No grade 3 toxicities attributable to re-RT were observed. Median progression-free and overall survival for re-RT patients were 6.5 and 7.1 months, respectively. CONCLUSIONS: Treatment of rGBM may be optimized by sMRI, and failure patterns suggest benefit for dose-escalation within sMRI-delineated volumes. Dose-escalation and radiologic-pathologic studies are underway to confirm the utility of sMRI in rGBM.

Distinct Profiles of DNA Repair Activity Define Favorable-risk Prostate Cancer Subtypes With Divergent Outcome.

INTRODUCTION: Understanding if divergent molecular profiles of DNA damage and repair (DDR) pathway activity, a biomarker of disease progression, exist in prostate tumors with favorable-risk features is an unmet need, which this study aim to unearth. MATERIALS AND METHODS: This was a multicenter registry genome-wide expression profiling study of prospectively collected radical prostatectomy (RP) tumor samples from 2014 to 2016. DDR activity was calculated from average expression of 372 DDR genes. Consensus hierarchical clustering was used to arrive at a robust clustering solution based on DDR gene expression patterns. Genome-wide differential expression between clusters was performed, and outcomes were evaluated across expression patterns. RESULTS: Of 5239 patients from the prospective registry, 376 had favorable-risk disease (Grade group [GG] 1 to 2, PSA prior to RP <10ng/ml, pT2 or less). DDR activity score was correlated with prognostic genomic signatures that predict for metastatic risk (r = 0.37, P < 2e-16) and high grade groups (P < .001). High DDR activity (top-quartile) was observed in 28% of patients with favorable-risk disease. In favorable-risk disease, 3 distinct clusters with varied DDR activity emerged with consensus clustering. Cluster I (compared with cluster II-III and GG3-GG5 disease) had the highest expression of all DDR sub-pathways, MYC, PAPR1, AR, and AR activity (P < .001 for all). Furthermore, cluster I was associated with poorer metastasis-free survival (MFS) and Overall survival (OS) compared with other clusters (MFS; HR: 2.43, 95%CI, [1.22-4.83], P = .01; OS; HR: 2.77, 95%CI, [1.18-6.5], P = .01). CONCLUSIONS: Cluster I is a novel subgroup of favorable-risk disease with high DDR activity, AR activity, PARP1 and chr8q/MYC expression, and poorer MFS and OS.

Associations of Metabolic Syndrome and Abdominal Obesity with Anion Gap Metabolic Acidosis among US Adults.

Background: Obesity is a recently identified risk factor for metabolic acidosis and anion gap elevations in the absence of CKD. Metabolic acidosis is a treatable condition with substantial adverse effects on human health. Additional investigations are needed to characterize at-risk populations and explore potential mechanisms. We hypothesized metabolic syndrome (MetS) and waist circumference (WC) would be closely associated with this pathology. Methods: Adult participants from NHANES 1999-2018 meeting study criteria were compiled as main (n=31,163) and fasting (n=12,860) cohorts. Regression models adjusted for dietary acid, eGFR, and other factors examined associations of WC and MetS features with anion gap metabolic acidosis and its components (serum bicarbonate ≤23 mEq/L and anion gap >95th percentile). Results: Greater WC and MetS features were associated with progressively lower bicarbonate, higher anion gap, and greater odds ratios (OR) of metabolic acidosis (MA) and anion gap metabolic acidosis (AGMA). Compared with the reference, participants with the highest WC had ORs for MA and AGMA of 2.26; 95% CI, 1.96 to 2.62 and 2.89; 95% CI, 1.97 to 4.21; those with three and four versus zero MetS features had ORs for AGMA of 2.52; 95% CI, 1.95 to 2.94 and 3.05; 95% CI, 2.16 to 3.82. Associations of body mass index with outcomes were attenuated or absent after adjustment for WC or MetS. Findings were preserved after excluding eGFR <90 ml/min per 1.73 m2 and albuminuria. A lower MA cutoff (<22 mEq/L) raised the estimate of association between MetS and MA (OR for three and four vs zero features: 3.56; 95% CI, 2.53 to 5.02 and 5.44; 95% CI, 3.66 to 8.08). Conclusions: Metabolic diseases are characterized by metabolic acidosis and anion gap elevations. Metabolic dysfunction may predispose patients without CKD to systemic acidosis from endogenous sources. Comprehensive acid-base analyses may be informative in patients with metabolic diseases.

Cone-beam CT delta-radiomics to predict genitourinary toxicities and international prostate symptom of prostate cancer patients: a pilot study.

For prostate cancer (PCa) patients treated with definitive radiotherapy (RT), acute and late RT-related genitourinary (GU) toxicities adversely impact disease-specific quality of life. Early warning of potential RT toxicities can prompt interventions that may prevent or mitigate future adverse events. During intensity modulated RT (IMRT) of PCa, daily cone-beam computed tomography (CBCT) images are used to improve treatment accuracy through image guidance. This work investigated the performance of CBCT-based delta-radiomic features (DRF) models to predict acute and sub-acute International Prostate Symptom Scores (IPSS) and Common Terminology Criteria for Adverse Events (CTCAE) version 5 GU toxicity grades for 50 PCa patients treated with definitive RT. Delta-radiomics models were built using logistic regression, random forest for feature selection, and a 1000 iteration bootstrapping leave one analysis for cross validation. To our knowledge, no prior studies of PCa have used DRF models based on daily CBCT images. AUC of 0.83 for IPSS and greater than 0.7 for CTCAE grades were achieved as early as week 1 of treatment. DRF extracted from CBCT images showed promise for the development of models predictive of RT outcomes. Future studies will include using artificial intelligence and machine learning to expand CBCT sample sizes available for radiomics analysis.

Addressing Challenges and Controversies in the Management of Prostate Cancer with Multidisciplinary Teams.

The diagnostic and treatment landscapes of prostate cancer are rapidly evolving. This has led to several challenges and controversies regarding optimal management of the disease that outpace guidelines and clinical data. Multidisciplinary teams (MDTs) can be used to engage the array of specialists that collaborate to treat complex malignancies such as prostate cancer. While the rationale for the use of MDTs in prostate cancer is well known, ways to optimally use MDTs to address the challenges and controversies associated with prostate cancer management are less well understood. One area of MDT care that remains undefined is how MDTs can most effectively provide guidance on clinical decision-making in situations in which information from novel diagnostic testing (genetic testing, molecular imaging) is substantially different from the established clinical risk factors. In this review, we provide a clinical perspective on ways that MDTs can be used to address this and other challenges and controversies across the prostate cancer disease continuum, from diagnosis to end-of-life considerations. Beyond clinical scenarios, we also review ways in which MDTs can mitigate disparities of care in prostate cancer. Overall, MDTs play a central role in helping to address the daily vexing issues faced by clinicians related to diagnosis, risk stratification, and treatment. Given the accelerating advances in precision medicine and targeted therapy, and the new questions and controversies these will bring, the value of MDTs for prostate cancer management will only increase in the future.

Continuous Long-Term Physical Activity Monitoring in Hemodialysis Patients.

Background: Physical inactivity is common in patients receiving hemodialysis, but activity patterns throughout the day and in relation to dialysis are largely unknown. This knowledge gap can be addressed by long-term continuous activity monitoring, but this has not been attempted and may not be acceptable to patients receiving dialysis. Methods: Ambulatory patients with end-stage kidney disease receiving thrice-weekly hemodialysis wore commercially available wrist-worn activity monitors for 6 months. Step counts were collected every 15 minutes and were linked to dialysis treatments. Physical function was assessed using the Short Physical Performance Battery (SPPB). Fast time to recovery from dialysis was defined as ≤2 hours. Mixed effects models were created to estimate step counts over time. Results: Of 52 patients enrolled, 48 were included in the final cohort. The mean age was 60 years, and 75% were Black or Hispanic. Comorbidity burden was high, 38% were transported to and from dialysis by paratransit, and 79% had SPPB <10. Median accelerometer use (199 days) and adherence (95%) were high. Forty-two patients (of 43 responders) reported wearing the accelerometer every day, and few barriers to adherence were noted. Step counts were lower on dialysis days (3991 [95% CI, 3187 to 4796] versus 4561 [95% CI, 3757 to 5365]), but step-count intensity was significantly higher during the hour immediately after dialysis than during the corresponding time on nondialysis days (188 steps per hour increase [95% CI, 171 to 205]); these levels were the highest noted at any time. Postdialysis increases were more pronounced among patients with fast recovery time (225 [95% CI, 203 to 248] versus 134 [95% CI, 107 to 161] steps per hour) or those with SPPB ≥7. Estimates were unchanged after adjustment for demographics, diabetes status, and ultrafiltration rate. Conclusions: Long-term continuous monitoring of physical activity is feasible in patients receiving hemodialysis. Highly granular data collection and analysis yielded new insights into patterns of activity after dialysis treatments.

Longitudinal Changes and Predictive Value of Multiparametric MRI Features for Prostate Cancer Patients Treated with MRI-Guided Lattice Extreme Ablative Dose (LEAD) Boost Radiotherapy.

We investigated the longitudinal changes in multiparametric MRI (mpMRI) (T2-weighted, Apparent Diffusion Coefficient (ADC), and Dynamic Contrast Enhanced (DCE-)MRI) of prostate cancer patients receiving Lattice Extreme Ablative Dose (LEAD) radiotherapy (RT) and the capability of their imaging features to predict RT outcome based on endpoint biopsies. Ninety-five mpMRI exams from 25 patients, acquired pre-RT and at 3-, 9-, and 24-months post-RT were analyzed. MRI/Ultrasound-fused biopsies were acquired pre- and at two-years post-RT (endpoint). Five regions of interest (ROIs) were analyzed: Gross tumor volume (GTV), normally-appearing tissue (NAT) and peritumoral volume in both peripheral (PZ) and transition (TZ) zones. Diffusion and perfusion radiomics features were extracted from mpMRI and compared before and after RT using two-tailed Student t-tests. Selected features at the four scan points and their differences (Δ radiomics) were used in multivariate logistic regression models to predict the endpoint biopsy positivity. Baseline ADC values were significantly different between GTV, NAT-PZ, and NAT-TZ (p-values < 0.005). Pharmaco-kinetic features changed significantly in the GTV at 3-month post-RT compared to baseline. Several radiomics features at baseline and three-months post-RT were significantly associated with endpoint biopsy positivity and were used to build models with high predictive power of this endpoint (AUC = 0.98 and 0.89, respectively). Our study characterized the RT-induced changes in perfusion and diffusion. Quantitative imaging features from mpMRI show promise as being predictive of endpoint biopsy positivity.

Clinical Consequences of Metabolic Acidosis-Muscle.

Metabolic acidosis is common in people with chronic kidney disease and can contribute to functional decline, morbidity, and mortality. One avenue through which metabolic acidosis can result in these adverse clinical outcomes is by negatively impacting skeletal muscle; this can occur through several pathways. First, metabolic acidosis promotes protein degradation and impairs protein synthesis, which lead to muscle breakdown. Second, metabolic acidosis hinders mitochondrial function, which decreases oxidative phosphorylation and reduces energy production. Third, metabolic acidosis directly limits muscle contraction. The purpose of this review is to examine the specific mechanisms of each pathway through which metabolic acidosis affects muscle, the impact of metabolic acidosis on physical function, and the effect of treating metabolic acidosis on functional outcomes.

Survival and Yield of Surveillance Imaging in Long-Term Survivors of Brain Metastasis Treated with Stereotactic Radiosurgery.

OBJECTIVES: The optimal frequency of surveillance brain magnetic resonance imaging (MRI) in long-term survivors with brain metastases after stereotactic radiosurgery (SRS) is unknown. Our aim was to identify the optimal frequency of surveillance imaging in long-term survivors with brain metastases after SRS. METHODS: Eligible patients were identified from a cohort treated with SRS definitively or postoperatively at our institution from 2014 to 2019 with no central nervous system (CNS) failure within 12 months from SRS. Time to CNS disease failure diagnosis and cost per patient were estimated using theoretical MRI schedules of 2, 3, 4, and 6 months starting 1 year after SRS until CNS failure. Time to diagnosis was calculated from the date of CNS progression to the theoretical imaging date on each schedule. RESULTS: This cohort included 55 patients (median follow-up from SRS: 2.48 years). During the study period, 20.0% had CNS disease failure (median: 2.26 years from SRS treatment). In this cohort, a theoretical 2-month, 3-month, 4-month, and 6-month MRI brain surveillance schedule produced a respective estimated time to diagnosis of CNS disease failure of 1.11, 1.74, 1.65, and 3.65 months. The cost of expedited diagnosis for the cohort (dollars/month) for each theoretical imaging schedule compared with a 6-month surveillance schedule was $6600 for a 2-month protocol, $4496 for a 3-month protocol, and $2180 for a 4-month protocol. CONCLUSIONS: Based on cost-benefit, a 4-month MRI brain schedule should be considered in patients with metastatic disease to the brain treated definitively or postoperatively with SRS without evidence of CNS recurrence at 1 year.

Serum bicarbonate levels and gait abnormalities in older adults: a cross-sectional study.

Metabolic acidosis is associated with impaired physical function in patients with chronic kidney disease (CKD) and older adults. However, whether acidosis is associated with gait abnormalities has received little attention. In a cohort of 323 community-dwelling adults ≥ 65 years old who underwent quantitative gait analysis, we examined associations of serum bicarbonate with eight individual gait variables. After multivariable adjustment, participants in the lowest bicarbonate tertile (< 25 mEq/L) had 8.6 cm/s slower speed (95% confidence interval [CI] 3.2-13.9), 7.9 cm shorter stride length (95% CI 3.5-12.2), and 0.03 s longer double support time (95% CI 0.002-0.1) compared with those in the middle tertile (25-27 mEq/L). Furthermore, lower bicarbonate levels were associated with more severe gait abnormalities in a graded manner. After further adjustment for possible mediating factors, associations were attenuated but remained significant. Among participants with CKD, associations were of similar or greater magnitude compared with those without CKD. Factor analysis was performed to synthesize the individual gait variables into unifying domains: among the pace, rhythm, and variability domains, lower serum bicarbonate was associated with worse performance in pace. In sum, lower serum bicarbonate was independently associated with worse performance on several quantitative measures of gait among older adults.

A Single Axial Slice of the Sternocleidomastoids and Paravertebral Muscles Associated with Worse Local Progression-Free Survival and Severe Toxicity in Sarcopenic Head and Neck Cancer Patients Undergoing Radiotherapy.

Objective The objective of this study is to contrast the predictive ability of targeted muscle groups as radiographic proxies of sarcopenia on computerized tomography (CT) with body mass index (BMI) in head and neck cancer patients (H&NCP) undergoing radiation at a safety net hospital, and to evaluate sarcopenia with survival, local progression, toxicities and treatment delays. Methods A retrospective review included 52 H&NCP treated between 2017-2019. The posterior neck muscles (PN), sternocleidomastoids (SCM), and their summed volume (AM) were contoured at C3 on patients' pre-treatment CT scans, then normalized to obtain skeletal muscle index (MI) values. Pre-treatment BMI was also evaluated. Cutoffs for sarcopenia were determined by receiver operating characteristic curves. Overall survival and local recurrence-free survival were evaluated by Kaplan-Meier. Acute grade 3 or higher toxicities were evaluated by binomial logistic regression. Results Using all neck muscles (AM-MI) produced the best model for predicting outcomes, outperforming individual muscle groups and BMI. Local progression-free survival was worse in sarcopenic patients at 25.81 months versus 35.40 months (p=0.026). Acute grade 3 or higher toxicities were associated with sarcopenia (p=0.005). Conclusions In this small, retrospective single-institution experience at a safety net hospital, a single axial slice of the combined sternocleidomastoids and paravertebral muscles at C3 performed better than either muscle group alone or pre-treatment BMI at predicting oncologic outcomes.