Multi-modal MRI of hippocampal morphometry and connectivity after pediatric severe TBI

This investigation explores memory performance using the California Verbal Learning Test in relation to morphometric and connectivity measures of the memory network in severe traumatic brain injury. Twenty-two adolescents with severe traumatic brain injury were recruited for multimodal MRI scanning 1-2 years post-injury at 13 participating sites. Analyses included hippocampal volume derived from anatomical T1-weighted imaging, fornix white matter microstructure from diffusion tensor imaging, and hippocampal resting-state functional magnetic resonance imaging connectivity as well as diffusion-based structural connectivity. A typically developing control cohort of forty-nine age-matched children also underwent scanning and neurocognitive assessment. Results showed hippocampus volume was decreased in traumatic brain injury with respect to controls. Further, hippocampal volume loss was associated with worse performance on memory and learning in traumatic brain injury subjects. Similarly, hippocampal fornix fractional anisotropy was reduced in traumatic brain injury with respect to controls, while decreased fractional anisotropy in the hippocampal fornix also was associated with worse performance on memory and learning in traumatic brain injury subjects. Additionally, reduced structural connectivity of left hippocampus to thalamus and calcarine sulcus was associated with memory and learning in traumatic brain injury subjects. Functional connectivity in the left hippocampal network was also associated with memory and learning in traumatic brain injury subjects. These regional findings from a multi-modal neuroimaging approach should not only be useful for gaining valuable insight into traumatic brain injury induced memory and learning disfunction, but may also be informative for monitoring injury progression, recovery, and for developing rehabilitation as well as therapy strategies.

Effects of inpatient rehabilitation after acute care on motor, neuropsychological and behavioral outcomes in children with severe traumatic brain injury

PURPOSE

An observational study of children with severe traumatic brain injury (TBI) (Approaches and Decisions in Acute Pediatric TBI [ADAPT] Trial) demonstrated the benefits of inpatient rehabilitation on functional outcomes for those with more severely impaired consciousness when medically stable. We conducted a secondary analysis to assess whether using an inpatient rehabilitation or skilled nursing facility after acute hospitalization was associated with better motor, neuropsychological, and behavioral outcomes compared to receiving only non-inpatient rehabilitation among children with severe TBI.

MATERIALS AND METHODS

We included 180 children who used an inpatient rehabilitation or skilled nursing facility and 74 children who only received non-inpatient rehabilitation from the ADAPT trial. At 12 months post-injury, children underwent tests of motor skills, intellectual functioning, verbal learning, memory, processing speed, and cognitive flexibility. Parents/guardians rated children's executive function and behaviors. We performed inverse probability weighting to adjust for potential confounders.

RESULTS

No significant differences were found in any motor, neuropsychological, or behavioral measures between children receiving inpatient rehabilitation and children receiving only non-inpatient rehabilitation.

CONCLUSIONS

Analyses of comprehensive outcomes did not show differences between children receiving inpatient rehabilitation and children receiving only non-inpatient rehabilitation, suggesting a need for more research on specific components of the rehabilitation process.

Quantifying the risk of prosthetic joint infections after invasive dental procedures and the effect of antibiotic prophylaxis

BACKGROUND

Dentists face the expectations of orthopedic surgeons and patients with prosthetic joints to provide antibiotic prophylaxis (AP) before invasive dental procedures (IDPs) to reduce the risk of late periprosthetic joint infections (LPJIs), despite the lack of evidence associating IDPs with LPJIs, lack of evidence of AP efficacy, risk of AP-related adverse reactions, and potential for promoting antibiotic resistance. The authors aimed to identify any association between IDPs and LPJIs and whether AP reduces LPJI incidence after IDPs.

METHOD

The authors performed a case-crossover analysis comparing IDP incidence in the 3 months immediately before LPJI hospital admission (case period) with the preceding 12-month control period for all LPJI hospital admissions with commercial or Medicare supplemental or Medicaid health care coverage and linked dental and prescription benefits data.

RESULTS

Overall, 2,344 LPJI hospital admissions with dental and prescription records (n = 1,160 commercial or Medicare supplemental and n = 1,184 Medicaid) were identified. Patients underwent 4,614 dental procedures in the 15 months before LPJI admission, including 1,821 IDPs (of which 18.3% had AP). Our analysis identified no significant positive association between IDPs and subsequent development of LPJIs and no significant effect of AP in reducing LPJIs.

CONCLUSIONS

The authors identified no significant association between IDPs and LPJIs and no effect of AP cover of IDPs in reducing the risk of LPJIs.

PRACTICAL IMPLICATIONS

In the absence of benefit, the continued use of AP poses an unnecessary risk to patients from adverse drug reactions and to society from the potential of AP to promote development of antibiotic resistance. Dental AP use to prevent LPJIs should, therefore, cease.

Understanding a Care Management System's Role in Influencing a Transitional-Aged Youth Program's Practice: Mixed Methods Study

BACKGROUND

Extended foster care programs help prepare transitional-aged youth (TAY) to step into adulthood and live independent lives. Aspiranet, one of California's largest social service organizations, used a social care management solution (SCMS) to meet TAY's needs.

OBJECTIVE

We aimed to investigate the impact of an SCMS, IBM Watson Care Manager (WCM), in transforming foster program service delivery and improving TAY outcomes.

METHODS

We used a mixed methods study design by collecting primary data from stakeholders through semistructured interviews in 2021 and by pulling secondary data from annual reports, system use logs, and data repositories from 2014 to 2021. Thematic analysis based on grounded theory was used to analyze qualitative data using NVivo software. Descriptive analysis of aggregated outcome metrics in the quantitative data was performed and compared across 2 periods: pre-SCMS implementation (before October 31, 2016) and post-SCMS implementation (November 1, 2016, and March 31, 2021).

RESULTS

In total, 6 Aspiranet employees (4 leaders and 2 life coaches) were interviewed, with a median time of 56 (IQR 53-67) minutes. The majority (5/6, 83%) were female, over 30 years of age (median 37, IQR 32-39) with a median of 6 (IQR 5-10) years of experience at Aspiranet and overall field experience of 10 (IQR 7-14) years. Most (4/6, 67%) participants rated their technological skills as expert. Thematic analysis of participants' interview transcripts yielded 24 subthemes that were grouped into 6 superordinate themes: study context, the impact of the new tool, key strengths, commonly used features, expectations with WCM, and limitations and recommendations. The tool met users' initial expectations of streamlining tasks and adopting essential functionalities. Median satisfaction scores around pre- and post-WCM workflow processes remained constant between 2 life coaches (3.25, IQR 2.5-4); however, among leaders, post-WCM scores (median 4, IQR 4-5) were higher than pre-WCM scores (median 3, IQR 3-3). Across the 2 study phases, Aspiranet served 1641 TAY having consistent population demographics (median age of 18, IQR 18-19 years; female: 903/1641, 55.03%; race and ethnicity: Hispanic or Latino: 621/1641, 37.84%; Black: 470/1641, 28.64%; White: 397/1641, 24.19%; Other: 153/1641, 9.32%). Between the pre- and post-WCM period, there was an increase in full-time school enrollment (359/531, 67.6% to 833/1110, 75.04%) and a reduction in part-time school enrollment (61/531, 11.5% to 91/1110, 8.2%). The median number of days spent in the foster care program remained the same (247, IQR 125-468 years); however, the number of incidents reported monthly per hundred youth showed a steady decline, even with an exponentially increasing number of enrolled youth and incidents.

CONCLUSIONS

The SCMS for coordinating care and delivering tailored services to TAY streamlined Aspiranet's workflows and processes and positively impacted youth outcomes. Further enhancements are needed to better align with user and youth needs.

Effects of inpatient rehabilitation after acute care on functional and quality-of-life outcomes in children with severe traumatic brain injury

OBJECTIVE

Few studies have assessed the effectiveness of the rehabilitation process in children surviving severe traumatic brain injury (TBI). We evaluated whether receiving inpatient rehabilitation after acute hospitalization was associated with better functional outcomes compared to receiving only non-inpatient rehabilitation in children with severe TBI and explored an effect modification for Glasgow Coma Scale (GCS) score at hospital discharge.

METHODS

We included 254 children who received rehabilitation following severe TBI from a multinational observational study. The Pediatric Glasgow Outcome Scale - Extended (GOS-E Peds), parent/guardian-reported and child-reported Pediatric Quality of Life Inventory (PedsQL) at 12 months post-injury were assessed and described using summary statistics. Unadjusted and propensity score-weighted linear/ordinal logistic regression modeling were also performed.

RESULTS

180 children received inpatient rehabilitation and 74 children received only non-inpatient rehabilitation after acute hospitalization. Among children with a GCS<13 at discharge, those receiving inpatient rehabilitation had a more favorable GOS-E Peds score (OR = 0.12, p = 0.045). However, no such association was observed in children with a higher GCS. We found no differences in PedsQL scores between rehabilitation groups.

CONCLUSIONS

Future studies are warranted to confirm the benefits of inpatient rehabilitation for children with more severely impaired consciousness when medically stable.

Magnetic Resonance Imaging Findings in Infants with Severe Traumatic Brain Injury and Associations with Abusive Head Trauma

Young children with severe traumatic brain injury (TBI) have frequently been excluded from studies due to age and/or mechanism of injury. Magnetic resonance imaging (MRI) is now frequently being utilized to detect parenchymal injuries and early cerebral edema. We sought to assess MRI findings in infants with severe TBI, and to determine the association between specific MRI findings and mechanisms of injury, including abusive head trauma (AHT). MRI scans performed within the first 30 days after injury were collected and coded according to NIH/NINDS Common Data Elements (CDEs) for Neuroimaging in subjects age < 2 years old with severe TBI enrolled in the Approaches and Decisions in Acute Pediatric Traumatic Brain Injury Trial. Demographics and injury characteristics were analyzed. A total of 81 children were included from ADAPT sites with MRI scans. Median age was 0.77 years and 57% were male. Most common MRI finding was ischemia, present in 57/81 subjects (70%), in a median of 7 brain regions per subject. Contusion 46/81 (57%) and diffuse axonal injury (DAI) 36/81 (44.4%) subjects followed. Children were dichotomized based on likelihood of AHT with 43/81 subjects classified as AHT. Ischemia was found to be significantly associated with AHT (p = 0.001) and “inflicted” injury mechanism (p = 0.0003). In conclusion, the most common intracerebral injury seen on MRI of infants with severe TBI was ischemia, followed by contusion and DAI. Ischemia was associated with AHT, and ischemia affecting > 4 brain regions was predictive of AHT.

Comparative Effectiveness of Diversion of Cerebrospinal Fluid for Children With Severe Traumatic Brain Injury

IMPORTANCE

Diversion of cerebrospinal fluid (CSF) has been used for decades as a treatment for children with severe traumatic brain injury (TBI) and is recommended by evidenced-based guidelines. However, these recommendations are based on limited studies.

OBJECTIVE

To determine whether CSF diversion is associated with improved Glasgow Outcome Score-Extended for Pediatrics (GOS-EP) and decreased intracranial pressure (ICP) in children with severe TBI.

DESIGN, SETTING, AND PARTICIPANTS

This observational comparative effectiveness study was performed at 51 clinical centers that routinely care for children with severe TBI in 8 countries (US, United Kingdom, Spain, the Netherlands, Australia, New Zealand, South Africa, and India) from February 2014 to September 2017, with follow-up at 6 months after injury (final follow-up, October 22, 2021). Children with severe TBI were included if they had Glasgow Coma Scale (GCS) scores of 8 or lower, had intracranial pressure (ICP) monitor placed on-site, and were aged younger than 18 years. Children were excluded if they were pregnant or an ICP monitor was not placed at the study site. Consecutive children were screened and enrolled, data regarding treatments were collected, and at discharge, consent was obtained for outcomes testing. Propensity matching for pretreatment characteristics was performed to develop matched pairs for primary analysis. Data analyses were completed on April 18, 2022.

EXPOSURES

Clinical care followed local standards, including the use of CSF diversion (or not), with patients stratified at the time of ICP monitor placement (CSF group vs no CSF group).

MAIN OUTCOMES AND MEASURES

The primary outcome was GOS-EP at 6 months, while ICP was considered as a secondary outcome. CSF vs no CSF was treated as an intention-to-treat analysis, and a sensitivity analysis was performed for children who received delayed CSF diversion.

RESULTS

A total of 1000 children with TBI were enrolled, including 314 who received CSF diversion (mean [SD] age, 7.18 [5.45] years; 208 [66.2%] boys) and 686 who did not (mean [SD] age, 7.79 [5.33] years; 437 [63.7%] boys). The propensity-matched analysis included 98 pairs. In propensity score-matched analyses, there was no difference between groups in GOS-EP (median [IQR] difference, 0 [-3 to 1]; P = .08), but there was a decrease in overall ICP in the CSF group (mean [SD] difference, 3.97 [0.12] mm Hg; P < .001).

CONCLUSIONS AND RELEVANCE

In this comparative effectiveness study, CSF diversion was not associated with improved outcome at 6 months after TBI, but a decrease in ICP was observed. Given the higher quality of evidence generated by this study, current evidence-based guidelines related to CSF diversion should be reconsidered.

Comparison of Intracranial Pressure Measurements Before and After Hypertonic Saline or Mannitol Treatment in Children With Severe Traumatic Brain Injury

IMPORTANCE

Hyperosmolar agents are cornerstone therapies for pediatric severe traumatic brain injury. Guideline recommendations for 3% hypertonic saline (HTS) are based on limited numbers of patients, and no study to date has supported a recommendation for mannitol.

OBJECTIVES

To characterize current use of hyperosmolar agents in pediatric severe traumatic brain injury and assess whether HTS or mannitol is associated with greater decreases in intracranial pressure (ICP) and/or increases in cerebral perfusion pressure (CPP).

DESIGN, SETTING, AND PARTICIPANTS

In this comparative effectiveness research study, 1018 children were screened and 18 were excluded; 787 children received some form of hyperosmolar therapy during the ICP-directed phase of care, with 521 receiving a bolus. Three of these children were excluded because they had received only bolus administration of both HTS and mannitol in the same hour, leaving 518 children (at 44 clinical sites in 8 countries) for analysis. The study was conducted from February 1, 2014, to September 31, 2017, with follow-up for 1 week after injury. Final analysis was performed July 20, 2021.

INTERVENTIONS

Boluses of HTS and mannitol were administered.

MAIN OUTCOMES AND MEASURES

Data on ICP and CPP were collected before and after medication administration. Statistical methods included linear mixed models and corrections for potential confounding variables to compare the 2 treatments.

RESULTS

A total of 518 children (mean [SD] age, 7.6 [5.4] years; 336 [64.9%] male; 274 [52.9%] White) were included. Participants' mean (SD) Glasgow Coma Scale score was 5.2 (1.8). Bolus HTS was observed to decrease ICP and increase CPP (mean [SD] ICP, 1.03 [6.77] mm Hg; P < .001; mean [SD] CPP, 1.25 [12.47] mm Hg; P < .001), whereas mannitol was observed to increase CPP (mean [SD] CPP, 1.20 [11.43] mm Hg; P = .009). In the primary outcome, HTS was associated with a greater reduction in ICP compared with mannitol (unadjusted β, -0.85; 95% CI, -1.53 to -0.19), but no association was seen after adjustments (adjusted β, -0.53; 95% CI, -1.32 to 0.25; P = .18). No differences in CPP were observed. When ICP was greater than 20 mm Hg, greater than 25 mm Hg, or greater than 30 mm Hg, HTS outperformed mannitol for each threshold in observed ICP reduction (>20 mm Hg: unadjusted β, -2.51; 95% CI, -3.86 to -1.15, P < .001; >25 mm Hg: unadjusted β, -3.88; 95% CI, -5.69 to -2.06, P < .001; >30 mm Hg: unadjusted β, -4.07; 95% CI, -6.35 to -1.79, P < .001), with results remaining significant for ICP greater than 25 mm Hg in adjusted analysis.

CONCLUSIONS AND RELEVANCE

In this comparative effectiveness research study, bolus HTS was associated with lower ICP and higher CPP, whereas mannitol was associated only with higher CPP. After adjustment for confounders, both therapies showed no association with ICP and CPP. During ICP crises, HTS was associated with better performance than mannitol.

Characteristics Associated with the Use of an Inpatient Rehabilitation or Skilled Nursing Facility after Acute Care in Children with Severe Traumatic Brain Injury

To characterize inpatient rehabilitation services for children with severe traumatic brain injury (TBI), we included 254 children, whose parents/guardians reported receipt of rehabilitation within a 12-month follow-up period, from a multinational observational study. Children discharged to an inpatient rehabilitation or skilled nursing facility after acute care were classified into the "inpatient rehabilitation" group, and children discharged home after acute care were classified into the "non-inpatient rehabilitation" group. Multivariable regression analyses determined the associations of sociodemographic and clinical characteristics with rehabilitation groups. Children receiving inpatient rehabilitation had a shorter length of acute hospitalization. Children from the UK were less likely to receive inpatient rehabilitation compared to children from the US. Future studies are warranted to extend current findings by identifying the reasons behind differential access to inpatient rehabilitation among children with severe TBI.

Biomarkers for Traumatic Brain Injury: Data Standards and Statistical Considerations

Recent biomarker innovations hold potential for transforming diagnosis, prognostic modeling, and precision therapeutic targeting of traumatic brain injury (TBI). However, many biomarkers, including brain imaging, genomics, and proteomics, involve vast quantities of high-throughput and high-content data. Management, curation, analysis, and evidence synthesis of these data are not trivial tasks. In this review, we discuss data management concepts and statistical and data sharing strategies when dealing with biomarker data in the context of TBI research. We propose that application of biomarkers involves three distinct steps-discovery, evaluation, and evidence synthesis. First, complex/big data has to be reduced to useful data elements at the stage of biomarker discovery. Second, inferential statistical approaches must be applied to these biomarker data elements for assessment of biomarker clinical utility and validity. Last, synthesis of relevant research is required to support practice guidelines and enable health decisions informed by the highest quality, up-to-date evidence available. We focus our discussion around recent experiences from the International Traumatic Brain Injury Research (InTBIR) initiative, with a specific focus on four major clinical projects (Transforming Research and Clinical Knowledge in TBI, Collaborative European NeuroTrauma Effectiveness Research in TBI, Collaborative Research on Acute Traumatic Brain Injury in Intensive Care Medicine in Europe, and Approaches and Decisions in Acute Pediatric TBI Trial), which are currently enrolling subjects in North America and Europe. We discuss common data elements, data collection efforts, data-sharing opportunities, and challenges, as well as examine the statistical techniques required to realize successful adoption and use of biomarkers in the clinic as a foundation for precision medicine in TBI.

Complete human papillomavirus vaccination coverage over a 13-year period in a large population of privately insured U.S. patients

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Background: In the US, Human Papillomavirus (HPV) vaccination coverage is low, particularly in adolescents aged 13-15 years with respect to the Healthy People 2020 goal of 80%. There has been variability in the definition of measuring vaccination coverage in published studies. We examined complete HPV vaccination coverage in a population of privately insured individuals in the US. Methods: This retrospective study used IBM MarketScan Commercial Database, years 2006 to 2018. Inclusion criteria were ages 9 to 45 years and continuous enrollment from age 9 years or from 2006. Complete HPV vaccination coverage was defined as receipt of 2 doses (age 9-15 years) or 3 doses (age 16-45 years) within 12 months and stratified by year, demographics, and US region. Mean vaccination costs per dose were summarized by vaccine brand and health plan type. Results: The table summarizes complete HPV vaccination coverage by selected age groups for 2006 (n=12,221,938), 2010 (n=4,692,633), 2014 (n=2,808,132), and 2018 (n=1,662,148). From 2017 to 2018, the percentage of members who received HPV vaccine increased; for females ages 13-15 by 1% and 16-17 by 5% while for males ages 13-15 by 6% and 16-17 by 15%. In 2018, by region, the highest coverage was in females aged 18-26 at 53% and males aged 16-17 at 43% in the Northeast, and mean cost for each brand was $120 (-6% from 2017), $165 (-3%) and $220 (+5%) for Cervarix (n=151), Gardasil (n=8,201) and Gardasil 9 (n=139,356), respectively. The rate of utilization of Gardasil 9 increased from 33% (2015) to 94% (2018) of all vaccines. The lowest mean HPV vaccine cost by health plan type and brand was with Point-of-Service (POS) and Cervarix at $106, and the highest was with POS with Capitation and Gardasil 9 at $243. Conclusions: In a commercially insured US population, complete HPV vaccination coverage was lower than the Healthy People 2020 goal, but increased over time. Coverage varied according to health plan type and by region. In 2018, Gardasil 9 had the highest mean cost but was the most utilized vaccine, which may be related to broader coverage of HPV types. This study was limited by the transient nature of member enrollment and complexity of measuring complete vaccination coverage. These results should inform policy makers and practicing clinicians about the gap in vaccination coverage. [Table: see text]

Use of magnetic resonance imaging in severe pediatric traumatic brain injury: assessment of current practice

OBJECTIVE

There is no consensus on the optimal timing and specific brain MRI sequences in the evaluation and management of severe pediatric traumatic brain injury (TBI), and information on current practices is lacking. The authors performed a survey of MRI practices among sites participating in a multicenter study of severe pediatric TBI to provide information for designing future clinical trials using MRI to assess brain injury after severe pediatric TBI.

METHODS

Information on current imaging practices and resources was collected from 27 institutions participating in the Approaches and Decisions after Pediatric TBI Trial. Multiple-choice questions addressed the percentage of patients with TBI who have MRI studies, timing of MRI, MRI sequences used to investigate TBI, as well as the magnetic field strength of MR scanners used at the participating institutions and use of standardized MRI protocols for imaging after severe pediatric TBI.

RESULTS

Overall, the reported use of MRI in pediatric patients with severe TBI at participating sites was high, with 40% of sites indicating that they obtain MRI studies in > 95% of this patient population. Differences were observed in the frequency of MRI use between US and international sites, with the US sites obtaining MRI in a higher proportion of their pediatric patients with severe TBI (94% of US vs 44% of international sites reported MRI in at least 70% of patients with severe TBI). The reported timing and composition of MRI studies was highly variable across sites. Sixty percent of sites reported typically obtaining an MRI study within the first 7 days postinjury, with the remainder of responses distributed throughout the first 30-day postinjury period. Responses indicated that MRI sequences sensitive for diffuse axonal injury and ischemia are frequently obtained in patients with TBI, whereas perfusion imaging and spectroscopy techniques are less common.

CONCLUSIONS

Results from this survey suggest that despite the lack of consensus or guidelines, MRI is commonly obtained during the acute clinical setting after severe pediatric TBI. The variation in MRI practices highlights the need for additional studies to determine the utility, optimal timing, and composition of clinical MRI studies after TBI. The information in this survey describes current clinical MRI practices in children with severe TBI and identifies important challenges and objectives that should be considered when designing future studies.

Phase I randomized clinical trial of N-acetylcysteine in combination with an adjuvant probenecid for treatment of severe traumatic brain injury in children

Background

There are no therapies shown to improve outcome after severe traumatic brain injury (TBI) in humans, a leading cause of morbidity and mortality. We sought to verify brain exposure of the systemically administered antioxidant N-acetylcysteine (NAC) and the synergistic adjuvant probenecid, and identify adverse effects of this drug combination after severe TBI in children.

Methods

IRB-approved, randomized, double-blind, placebo controlled Phase I study in children 2 to 18 years-of-age admitted to a Pediatric Intensive Care Unit after severe TBI (Glasgow Coma Scale [GCS] score ≤8) requiring an externalized ventricular drain for measurement of intracranial pressure (ICP). Patients were recruited from November 2011-August 2013. Fourteen patients (n = 7/group) were randomly assigned after obtaining informed consent to receive probenecid (25 mg/kg load, then 10 mg/kg/dose q6h×11 doses) and NAC (140 mg/kg load, then 70 mg/kg/dose q4h×17 doses), or placebos via naso/orogastric tube. Serum and CSF samples were drawn pre-bolus and 1–96 h after randomization and drug concentrations were measured via UPLC-MS/MS. Glasgow Outcome Scale (GOS) score was assessed at 3 months.

Results

There were no adverse events attributable to drug treatment. One patient in the placebo group was withdrawn due to adverse effects. In the treatment group, NAC concentrations ranged from 16,977.3±2,212.3 to 16,786.1±3,285.3 in serum and from 269.3±113.0 to 467.9±262.7 ng/mL in CSF, at 24 to 72 h post-bolus, respectively; and probenecid concentrations ranged from 75.4.3±10.0 to 52.9±25.8 in serum and 5.4±1.0 to 4.6±2.1 μg/mL in CSF, at 24 to 72 h post-bolus, respectively (mean±SEM). Temperature, mean arterial pressure, ICP, use of ICP-directed therapies, surveillance serum brain injury biomarkers, and GOS at 3 months were not different between groups.

Conclusions

Treatment resulted in detectable concentrations of NAC and probenecid in CSF and was not associated with undesirable effects after TBI in children.

Trial registration

ClinicalTrials.gov NCT01322009

Outcomes of Osteomyelitis in Patients Hospitalized With Diabetic Foot Infections

BACKGROUND

This study was conducted to evaluate the outcomes of patients with diabetic foot osteomyelitis (DFO) compared to diabetic foot soft tissue infections (STIs).

METHODS

229 patients who were hospitalized with foot infections were retrospectively reviewed, identifying 155 patients with DFO and 74 patients with STI. Primary outcomes evaluated were the rates of amputations and length of hospital stay. DFO was confirmed by the presence of positive bone culture and/or histopathology.

RESULTS

Patients with DFO had a 5.6 times higher likelihood of overall amputation (P < .0001), a 3.4 times higher likelihood of major amputation (P = .027) and a 4.2 times higher likelihood of minor amputation (P < .0001) compared to patients without DFO. Major amputation was performed in 16.7% patients diagnosed with DFO and 5.3% of patients diagnosed with STI. Patients with DFO complicated by Charcot neuroarthropathy had a 7 times higher likelihood of undergoing major amputation (odds ratio 6.78, 95% confidence interval 2.70-17.01, P < .0001). The mean hospital stay was 7 days in DFO and 6 days in patients with DFI (P = .0082). Patients with DFO had a higher erythrocyte sedimentation rate (85 vs 71, P = .02) than patients with STI, however the differences in C-reactive protein (13.4 vs 11.8, P = .29) were not significantly different.

CONCLUSION

In this study of moderate and severe DFIs, the presence of osteomyelitis resulted in a higher likelihood of amputation and longer hospital stay. Readers should recognize that the findings of this study may not be applicable to less severe cases of DFO that can be effectively managed in an outpatient setting.

LEVEL OF EVIDENCE

Level III, retrospective comparative case series.

Sleep-Wake Differences in Relative Regional Cerebral Metabolic Rate for Glucose among Patients with Insomnia Compared with Good Sleepers

STUDY OBJECTIVES

The neurobiological mechanisms of insomnia may involve altered patterns of activation across sleep-wake states in brain regions associated with cognition, self-referential processes, affect, and sleep-wake promotion. The objective of this study was to compare relative regional cerebral metabolic rate for glucose (rCMR_glc) in these brain regions across wake and nonrapid eye movement (NREM) sleep states in patients with primary insomnia (PI) and good sleeper controls (GS).

METHODS

Participants included 44 PI and 40 GS matched for age (mean = 37 y old, range 21-60), sex, and race. We conducted [¹⁸F]fluoro-2-deoxy-D-glucose positron emission tomography scans in PI and GS during both morning wakefulness and NREM sleep at night. Repeated measures analysis of variance was used to test for group (PI vs. GS) by state (wake vs. NREM sleep) interactions in relative rCMR_glc.

RESULTS

Significant group-by-state interactions in relative rCMR_glc were found in the precuneus/posterior cingulate cortex, left middle frontal gyrus, left inferior/superior parietal lobules, left lingual/fusiform/occipital gyri, and right lingual gyrus. All clusters were significant at P_corrected < 0.05.

CONCLUSIONS

Insomnia was characterized by regional alterations in relative glucose metabolism across NREM sleep and wakefulness. Significant group-by-state interactions in relative rCMR_glc suggest that insomnia is associated with impaired disengagement of brain regions involved in cognition (left frontoparietal), self-referential processes (precuneus/posterior cingulate), and affect (left middle frontal, fusiform/lingual gyri) during NREM sleep, or alternatively, to impaired engagement of these regions during wakefulness.

Cerebral White Matter and Slow Gait: Contribution of Hyperintensities and Normal-appearing Parenchyma

BACKGROUND

White matter hyperintensities (WMH), a common marker of cerebral small vessel disease, and lower microstructural integrity of normal-appearing white matter are associated with slower gait. How these cerebral measures interact in relation to slower gait is unknown. We assessed whether microstructural integrity of normal-appearing white matter, measured by fractional anisotropy (FA), moderates the association of higher WMH with slower gait.

METHODS

WMH, FA, and gait speed were acquired for 265 community-dwelling older adults (average age = 82.9 years).

RESULTS

The inverse association between WMH and gait was robust to adjustment for age, gender, muscle strength, obesity, stroke, and hypertension (fully adjusted model: βs = -0.19, p = .001). The interaction between WMH and FA was significant; analyses stratified by FA showed that the inverse association between WMH and gait speed was significant only for those with low FA (FA < median, fully adjusted model: βs = -0.28, p = .001). Voxel-based results were similar for participants with FA less than median, there was an inverse association between gait speed and WMH which extended throughout the white matter (genu and body of corpus callosum, anterior limb of internal capsule, corona radiata, and superior longitudinal and fronto-occipital fasciculus). In contrast, for participants with FA ≥ median, the association was limited to the genu of corpus callosum, the cingulum, and the inferior longitudinal fasciculus.

CONCLUSIONS

Microstructural integrity is a moderating factor in the association between WMH and gait. Future studies should examine whether higher microstructural integrity represents a source of compensation in those with greater WMH burden to maintain function in late life.

Correlation of SF-36 and SF-12 Component Scores in Patients With Diabetic Foot Disease

The assessment of patient outcomes is becoming increasingly important in all areas of medicine, including foot and ankle surgery. The Medical Outcomes Study Short Form 36-item (SF-36) is widely used as a generic measure of quality of life; however, patients often find answering 36 questions cumbersome. Consequently, the Short Form 12 (SF-12) was developed. We hypothesized that the agreement between the SF-12 and SF-36 component scores would be substantial in patients with diabetic foot disease. We retrospectively reviewed the data from 300 patients with diabetes mellitus (DM) and foot and ankle pathology who completed the SF-36 questionnaire. Of the 300 patients, 155 (51.7%) had problems directly related to complications of DM and 145 (48.3%) had routine foot complaints that were unrelated to complications of DM. The 12 questions of the SF-12 were abstracted from the SF-36. The overall median score for the SF-36 physical component summary was 34.70 compared with the overall SF-12 physical component summary of 36.75 (p = .04). The intraclass correlation coefficient was 0.93688. The overall median score for the SF-36 mental component summary was 52.40 compared with the overall SF-12 mental component summary of 51.25 (p = .34). The intraclass correlation coefficient was 0.95449. Substantial agreement was observed when comparing the component scores of the SF-12 and the SF-36. From our study results of 300 patients with DM, it appears that the SF-36 and SF-12 are comparable outcome instruments for use with patients with diabetic foot disease.

Topically Applied Vancomycin Powder Reduces the Rate of Surgical Site Infection in Diabetic Patients Undergoing Foot and Ankle Surgery

BACKGROUND

The purpose of this study was to evaluate the efficacy of topically applied vancomycin powder in reducing the rate of surgical site infections (SSIs) in patients with diabetes mellitus (DM) undergoing foot and ankle surgery.

METHODS

Eighty-one patients with DM who underwent reconstructive surgery of a foot and/or ankle deformity and/or trauma and who received topically applied vancomycin were matched to 81 patients with DM who did not receive topically applied vancomycin. The mean age was 60.6 years in the vancomycin group and 59.4 years in the control group (P < .05). The 2 groups were similar with regard to gender, body mass index, duration of DM, short-term and longer term glycemic control, and length of surgery.

RESULTS

The overall likelihood of SSI was decreased by 73% in patients who received topically applied vancomycin (odds ratio [OR], 0.267; 95% CI, 0.089-0.803; P = .0188). The rate of superficial infection was not significantly different between the 2 groups (OR, 0.400; 95% CI, 0.078-2.062; P = .2734); however, deep infections were 80% less likely in patients who received vancomycin powder (OR, 0.200; 95% CI, 0.044-0.913; P = .0377).

CONCLUSION

High-risk diabetic patients undergoing foot and ankle surgery were notably less likely to develop an SSI with the use of topically applied vancomycin powder in the surgical wound, particularly with regard to deep infections. Topically applied vancomycin was associated with a very low rate of complications and was inexpensive ($5 per 1000 mg). Based on this study, foot and ankle surgeons may consider applying 500 to 1000 mg of vancomycin powder prior to skin closure in diabetic patients who are not allergic to vancomycin.

LEVEL OF EVIDENCE

Level III, retrospective case control series.

Midfoot Charcot Neuroarthropathy in Patients With Diabetes: The Impact of Foot Ulceration on Self-Reported Quality of Life

INTRODUCTION

Charcot neuroarthropathy (CN) and diabetic foot ulceration (DFU) are serious complications of diabetes mellitus (DM) that can result in infection, hospitalization, amputation, and have been shown to negatively affect quality of life (QOL). To the best of our knowledge, there are no studies in the literature that have specifically compared QOL in patients with diabetic CN without DFU to a group of patients with diabetic CN and concurrent DFU. The aim of this study was to compare self-reported assessments of QOL in patients with CN to a group of patients with CN and concomitant midfoot ulceration.

MATERIALS AND METHODS

We compared a group of 35 diabetic patients with midfoot CN and no ulcer to a group of 22 diabetic patients with midfoot CN and concurrent DFU. Self-reported outcome was assessed using the Medical Outcome Study Short Form 36 (SF-36) health survey and Foot and Ankle Ability Measure (FAAM).

RESULTS

No significant differences were found when comparing the 2 groups utilizing the SF-36 and FAAM with the exception that CN patients without foot ulcers had lower mean scores on the Bodily Pain Subscale. Both groups demonstrated negative impact on physical QOL and lower extremity function to a greater degree than mental QOL.

CONCLUSION

The presence of ulceration does not appear to significantly impact QOL in patients with CN when compared to patients with CN without ulceration.

LEVELS OF EVIDENCE

Prognostic, Level III: Case control.

Relative 11C-PiB Delivery as a Proxy of Relative CBF: Quantitative Evaluation Using Single-Session 15O-Water and 11C-PiB PET

The primary goal of this study was to assess the suitability of (11)C-Pittsburgh compound B ((11)C-PiB) blood-brain barrier delivery (K1) and relative delivery (R1) parameters as surrogate indices of cerebral blood flow (CBF), with a secondary goal of directly examining the extent to which simplified uptake measures of (11)C-PiB retention (amyloid-β load) may be influenced by CBF, in a cohort of controls and patients with mild cognitive impairment (MCI) and Alzheimer disease (AD).

METHODS

Nineteen participants (6 controls, 5 AD, 8 MCI) underwent MR imaging, (15)O-water PET, and (11)C-PiB PET in a single session. Fourteen regions of interest (including cerebellar reference region) were defined on MR imaging and applied to dynamic coregistered PET to generate time-activity curves. Multiple analysis approaches provided regional (15)O-water and (11)C-PiB measures of delivery and (11)C-PiB retention that included compartmental modeling distribution volume ratio (DVR), arterial- and reference-based Logan DVR, simplified reference tissue modeling 2 (SRTM2) DVR, and standardized uptake value ratios. Spearman correlation was performed among delivery measures (i.e., (15)O-water K1 and (11)C-PiB K1, relative K1 normalized to cerebellum [Rel-K1-Water and Rel-K1-PiB], and (11)C-PiB SRTM2-R1) and between delivery measures and (11)C-PiB retention, using the Bonferroni method for multiple-comparison correction.

RESULTS

Primary analysis showed positive correlations (ρ ≈0.2-0.5) between (15)O-water K1 and (11)C-PiB K1 that did not survive Bonferroni adjustment. Significant positive correlations were found between Rel-K1-Water and Rel-K1-PiB and between Rel-K1-Water and (11)C-PiB SRTM2-R1 (ρ ≈0.5-0.8, P < 0.0036) across primary cortical regions. Secondary analysis showed few significant correlations between (11)C-PiB retention and relative (11)C-PiB delivery measures (but not (15)O-water delivery measures) in primary cortical areas that arose only after accounting for cerebrospinal fluid dilution.

CONCLUSION

(11)C-PiB SRTM2-R1 is highly correlated with regional relative CBF, as measured by (15)O-water K1 normalized to cerebellum, and cross-sectional (11)C-PiB retention did not strongly depend on CBF across primary cortical regions. These results provide further support for potential dual-imaging assessments of regional brain status (i.e., amyloid-β load and relative CBF) through dynamic (11)C-PiB imaging.

Exposure to high concentrations of inspired oxygen does not worsen lung injury after cardiac arrest

Introduction

Post-cardiac arrest patients are often exposed to 100% oxygen during cardiopulmonary resuscitation and the early post-arrest period. It is unclear whether this contributes to development of pulmonary dysfunction or other patient outcomes.

Methods

We performed a retrospective cohort study including post-arrest patients who survived and were mechanically ventilated at least 24 hours after return of spontaneous circulation. Our primary exposure of interest was inspired oxygen, which we operationalized by calculating the area under the curve of the fraction of inspired oxygen (FiO₂AUC) for each patient over 24 hours. We collected baseline demographic, cardiovascular, pulmonary and cardiac arrest-specific covariates. Our main outcomes were change in the respiratory subscale of the Sequential Organ Failure Assessment score (SOFA-R) and change in dynamic pulmonary compliance from baseline to 48 hours. Secondary outcomes were survival to hospital discharge and Cerebral Performance Category at discharge.

Results

We included 170 patients. The first partial pressure of arterial oxygen (PaO2):FiO2 ratio was 241 ± 137, and 85% of patients had pulmonary failure and 55% had cardiovascular failure at presentation. Higher FiO₂AUC was not associated with change in SOFA-R score or dynamic pulmonary compliance from baseline to 48 hours. However, higher FiO₂AUC was associated with decreased survival to hospital discharge and worse neurological outcomes. This was driven by a 50% decrease in survival in the highest quartile of FiO₂AUC compared to other quartiles (odds ratio for survival in the highest quartile compared to the lowest three quartiles 0.32 (95% confidence interval 0.13 to 0.79), P = 0.003).

Conclusions

Higher exposure to inhaled oxygen in the first 24 hours after cardiac arrest was not associated with deterioration in gas exchange or pulmonary compliance after cardiac arrest, but was associated with decreased survival and worse neurological outcomes.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-0824-x) contains supplementary material, which is available to authorized users.

Tibiotalocalcaneal Arthrodesis Using Retrograde Intramedullary Nail Fixation: Comparison of Patients With and Without Diabetes Mellitus

Retrograde intramedullary nailing for tibiotalocalcaneal arthrodesis is a salvage procedure reserved for severe cases of deformity. The aim of the present study was to compare the outcomes of this technique in patients with and without diabetes mellitus (DM). A total of 61 patients with and 56 without DM underwent retrograde intramedullary nailing and had a minimum follow-up period of 12 months. The overall incidence of complication was 45.2%; however, the overall incidence of complications between those with and without DM was not significantly different (odds ratio [OR] 0.79, 95% confidence interval [CI] 0.38 to 1.65, p = .54). Patients with DM had a significantly greater rate of superficial infections (OR 8.3, 95% CI 1.01 to 68.67, p = .03). However, no difference was seen in the rate of deep infection (OR 0.90, 95% CI 0.34 to 2.46, p = .83) or noninfectious complications (OR 0.50, 95% CI 0.23 to 1.13, p = .09). Successful limb salvage was achieved for 96.8% of the patients with DM and 94.7% of those without DM (p = .66). A femoral head allograft was used in 32 (27.4%) of 117 patients to substitute for an osseous void. Of the 32 patients who required a femoral head allograft, 21 (67.7%) experienced a complication compared with 32 (37.6%) of 85 patients who did not require a femoral head allograft (OR 3.16, 95% CI 1.35 to 7.41, p = .008). The incidence of patient satisfaction was 80% for patients with DM and 72% for those without DM (p = .36). Despite a high incidence of complications, limb salvage was accomplished in approximately 95% of patients with complicated deformities. Four patients (6.56%) with DM experienced a tibia fracture; therefore, we now routinely use a 300-mm-long nail for this reconstruction.

Neuropathy and poorly controlled diabetes increase the rate of surgical site infection after foot and ankle surgery

BACKGROUND

This prospective study was designed to evaluate the frequency of surgical site infection in patients treated with foot and ankle surgery. Our hypothesis was that patients with complications of diabetes are at increased risk for surgical site infection compared with patients without diabetes and patients with diabetes who do not have diabetic complications. Another goal was to compare the association of neuropathy with surgical site infection in both nondiabetic and diabetic patients.

METHODS

Two thousand and sixty consecutive surgical cases were evaluated. Group 1 included nondiabetic patients without neuropathy, Group 2 included nondiabetic patients with neuropathy, Group 3 included patients with diabetes but no diabetic complications, and Group 4 included patients with diabetes who had at least one complication of diabetes.

RESULTS

The surgical site infection rate in this study was 3.1%. Patients with complicated diabetes had a 7.25-fold increased risk of surgical site infection compared with nondiabetic patients without neuropathy and a 3.72-fold increased risk compared with patients with uncomplicated diabetes. Patients with complicated diabetes had a nonsignificant 1.54-fold higher rate of surgical site infection compared with nondiabetic patients with neuropathy. Nondiabetic patients with neuropathy had a significant 4.72-fold increased risk of surgical site infection compared with nondiabetic patients without neuropathy. Despite this, nondiabetic patients with neuropathy did not have a significantly higher rate of surgical site infection than patients with uncomplicated diabetes, and the frequency of surgical site infection in the group with uncomplicated diabetes was not significantly different from that in the nondiabetic patients without neuropathy. Multivariable logistic regression analysis demonstrated that peripheral neuropathy and a hemoglobin A1c of ≥8% were independently associated with surgical site infection.

CONCLUSIONS

Complicated diabetes increases the risk of surgical site infection after foot and ankle surgery. Patients who had diabetes without complications did not have a greater risk of surgical site infection compared with nondiabetic patients without neuropathy. The presence of neuropathy increases the risk of surgical site infection even in patients without diabetes. Poor long-term glycemic control is also associated with an increased risk of surgical site infection.

LEVEL OF EVIDENCE

Prognostic Level I. See Instructions for Authors for a complete description of levels of evidence.

Successful tactile based visual sensory substitution use functions independently of visual pathway integrity

PURPOSE

Neuronal reorganization after blindness is of critical interest because it has implications for the rational prescription of artificial vision devices. The purpose of this study was to distinguish the microstructural differences between perinatally blind (PB), acquired blind (AB), and normally sighted controls (SCs) and relate these differences to performance on functional tasks using a sensory substitution device (BrainPort).

METHODS

We enrolled 52 subjects (PB n = 11; AB n = 35; SC n = 6). All subjects spent 15 h undergoing BrainPort device training. Outcomes of light perception, motion, direction, temporal resolution, grating, and acuity were tested at baseline and after training. Twenty-six of the subjects were scanned with a three Tesla MRI scanner for diffusion tensor imaging (DTI), and with a positron emission tomography (PET) scanner for mapping regional brain glucose consumption during sensory substitution function. Non-parametric models were used to analyze fractional anisotropy (FA; a DTI measure of microstructural integrity) of the brain via region-of-interest (ROI) analysis and tract-based spatial statistics (TBSS).

RESULTS

At baseline, all subjects performed all tasks at chance level. After training, light perception, time resolution, location and grating acuity tasks improved significantly for all subject groups. ROI and TBSS analyses of FA maps show areas of statistically significant differences (p ≤ 0.025) in the bilateral optic radiations and some visual association connections between all three groups. No relationship was found between FA and functional performance with the BrainPort.

DISCUSSION

All subjects showed performance improvements using the BrainPort irrespective of nature and duration of blindness. Definite brain areas with significant microstructural integrity changes exist among PB, AB, and NC, and these variations are most pronounced in the visual pathways. However, the use of sensory substitution devices is feasible irrespective of microstructural integrity of the primary visual pathways between the eye and the brain. Therefore, tongue based devices devices may be usable for a broad array of non-sighted patients.

Sleep disturbance and cardiometabolic risk factors in early pregnancy: a preliminary study

BACKGROUND

Cardiometabolic (CM) risk factors are linked to increased morbidity. Disturbed sleep is associated with CM risk factors in late pregnancy, but little is known about sleep in early pregnancy and CM risk factors.

METHODS

Diary and actigraphy-assessed sleep information, as well as CM outcomes (blood pressure (BP) and body mass index (BMI)), were collected thrice from pregnant women (N=161) in early pregnancy: T1 (10-12 weeks), T2 (14-16 weeks) and T3 (18-20 weeks). The sleep variables evaluated included sleep onset latency (SOL), wake after sleep onset (WASO) and total sleep time (TST). Sleep variables were dichotomised using established clinical cut-offs.

RESULTS

BMI and BP significantly changed across time. Women with persistent SOL≥20 min had greater BMI than women without persistent SOL≥20 min prior to covariate adjustment at T1 and T2, but at T3 the BMI values converged. Similar results were observed for persistent WASO≥30 min. Persistently long WASO, as measured by actigraphy, was associated with elevated SBP, after controlling for covariates.

CONCLUSIONS

Consistent with anecdotal evidence, it appears as if a subset of women report substantial difficulty initiating and maintaining sleep during early pregnancy and this may augment the risk of higher BP and BMI. Understanding these relationships is important as CM risk factors are linked to maternal and infant morbidity. Assessing sleep in early pregnancy may bestow time necessary for appropriate intervention.

The association between perioperative allogeneic transfusion volume and postoperative infection in patients following lumbar spine surgery

BACKGROUND

Perioperative allogeneic red blood cell transfusion is a risk factor for surgical site infection. The purpose of this study was to determine if the volume of perioperative allogeneic red blood cell transfusion influences the risk of surgical site infection following lumbar spine procedures.

METHODS

A retrospective matched case control study was performed by reviewing all patients who had undergone lumbar spine surgery at our institution from 2005 to 2009. Surgical site infections (spinal or iliac crest) were identified, all within thirty days of the procedure. Controls were matched to the infection cohort according to age, sex, body mass index, diabetic status, smoking status, Charlson Comorbidity Index, length of surgery, and procedure. A conditional logistic regression was performed to examine the association between transfusion volume and surgical site infection. The results were summarized by an odds ratio.

RESULTS

A total of 1799 lumbar procedures were identified with an infection rate of 3.1% (fifty-six cases). On the basis of the numbers, there was no significant difference in the matched variables between the infection cohort and the matched controls. The volume of transfusion was significantly associated with surgical site infection (odds ratio, 4.00 [95% confidence interval, 1.96 to 8.15]) after adjusting for both unmatched variables of preoperative hemoglobin level and volume of intraoperative blood loss.

CONCLUSIONS

In this retrospective matched case control study, the association between surgical site infection following lumbar spine surgery and volume of perioperative allogeneic red blood cell transfusion was supported.

SIRS is valid in discriminating between severe and moderate diabetic foot infections

OBJECTIVE

This retrospective, single-center study was designed to distinguish severe diabetic foot infection (DFI) from moderate DFI based on the presence or absence of systemic inflammatory response syndrome (SIRS).

RESEARCH DESIGN AND METHODS

The database of a single academic foot and ankle program was reviewed and 119 patients were identified. Severe DFI was defined as local infection associated with manifestation of two or more objective findings of systemic toxicity using SIRS criteria.

RESULTS

Patients with severe DFI experienced a 2.55-fold higher risk of any amputation (95% CI 1.21-5.36) and a 7.12-fold higher risk of major amputation (1.83-41.05) than patients with moderate DFI. The risk of minor amputations was not significantly different between the two groups (odds ratio 1.02 [95% CI 0.51-2.28]). The odds of having a severe DFI was 7.82 times higher in patients who presented with gangrene (2.03-44.81) and five times higher in patients who reported symptoms of anorexia, chills, nausea, or vomiting (2.22-11.25). The mean hospital length of stay for patients with severe DFI was ∼4 days longer than for patients with moderate DFI, and this difference was statistically significant.

CONCLUSIONS

SIRS is valid in distinguishing severe from moderate DFI in hospitalized patients. Patients with severe DFI, as by manifesting two or more signs of systemic inflammation or toxicity, had higher rates of major amputation and longer hospital stays and required more surgery and more subsequent admissions than patients who did not manifest SIRS.

Magnetic resonance imaging investigation of macrophages in acute cardiac allograft rejection after heart transplantation

BACKGROUND

Current immunosuppressive therapy after heart transplantation either generally suppresses the recipient's entire immune system or is mainly targeting T-lymphocytes. Monocytes/macrophages are recognized as a hallmark of acute allograft rejection, but the roles that they play are not well characterized in vivo, because the tools for accessing in situ macrophage infiltration are lacking. In this study, we used MRI to investigate the role of macrophages in acute heart allograft rejection by cellular and functional MRI with selectively depleted systemic macrophages without affecting other leukocyte population, as well as to explore the possibility that macrophages could be an alternative therapeutic target.

METHODS AND RESULTS

A rodent heterotopic working heart-lung transplantation model was used for studying acute allograft rejection. Systemic macrophages were selectively depleted by treating recipient animals with clodronate-liposomes. Macrophage infiltration in the graft hearts was monitored by cellular MRI with in vivo ultrasmall superparamagnetic iron oxide particles labeling. Graft heart function was evaluated by tagging MRI followed by strain analysis. Clodronate-liposome treatment depletes circulating monocytes/macrophages in transplant recipients, and both cellular MRI and pathological examinations indicate a significant reduction in macrophage accumulation in the rejecting allograft hearts. In clodronate-liposome-treated group, allograft hearts exhibited preserved tissue integrity, partially reversed functional deterioration, and prolonged graft survival, compared with untreated controls.

CONCLUSIONS

Cardiac cellular and functional MRI is a powerful tool to explore the roles of targeted immune cells in vivo. Our results indicate that macrophages are essential in acute cardiac allograft rejection, and selective depletion of macrophages with clodronate-liposomes protects hearts against allograft rejection, suggesting a potential therapeutic avenue. Our findings show that there is a finite risk of forming an intraventricular mass, presumably from the cellular debris or lipid material. Further optimization of the dosing protocol is necessary before clinical applications.

Fibrosis reduces severity of acute-on-chronic pancreatitis in humans

BACKGROUND & AIMS

Acute pancreatitis (AP) and chronic pancreatitis (CP) share etiologies, but AP can be more severe and is associated with a higher rate of mortality. We investigated features of CP that protect against severe disease. The amount of intrapancreatic fat (IPF) is increased in obese patients and fibrosis is increased in patients with CP, so we studied whether fibrosis or fat regulate severity of AP attacks in patients with CP.

METHODS

We reviewed records from the University of Pittsburgh Medical Center/Presbyterian Hospital Autopsy Database (1998-2008) for patients with a diagnosis of AP (n = 23), CP (n = 35), or both (AP-on-CP; n = 15). Pancreatic histology samples from these patients and 50 randomly selected controls (no pancreatic disease) were analyzed, and IPF data were correlated with computed tomography data. An adipocyte and acinar cell Transwell coculture system, with or without collagen type I, was used to study the effects of fibrosis on acinar-adipocyte interactions. We studied the effects of nonesterified fatty acids (NEFAs) and adipokines on acinar cells in culture.

RESULTS

Levels of IPF were significantly higher in nonobese patients with CP than in nonobese controls. In patients with CP or AP-on-CP, areas of IPF were surrounded by significantly more fibrosis than in controls or patients with AP. Fat necrosis-associated peri-fat acinar necrosis (PFAN, indicated by NEFA spillage) contributed to most of the necrosis observed in samples from patients with AP; however, findings of peri-fat acinar necrosis and total necrosis were significantly lower in samples from patients with CP or AP-on-CP. Fibrosis appeared to wall off the fat necrosis and limit peri-fat acinar necrosis, reducing acinar necrosis. In vitro, collagen I limited the lipolytic flux between acinar cells and adipocytes and prevented increases in adipokines in the acinar compartment. This was associated with reduced acinar cell necrosis. However, NEFAs, but not adipokines, caused acinar cell necrosis.

CONCLUSIONS

Based on analysis of pancreatic samples from patients with CP, AP, or AP-on-CP and in vitro studies, fibrosis reduces the severity of acute exacerbations of CP by reducing lipolytic flux between adipocytes and acinar cells.

In vivo assessment of amyloid-β deposition in nondemented very elderly subjects

OBJECTIVE

This study examined amyloid-β (Aβ) deposition in 190 nondemented subjects aged ≥82 years to determine the proportion of Aβ-positive scans and associations with cognition, apolipoprotein E (APOE) status, brain volume, and Ginkgo biloba (Gb) treatment.

METHODS

Subjects who agreed to participate had a brain magnetic resonance imaging and positron emission tomography scan with (11) C-labeled Pittsburgh compound B (PiB) following completion of a Gb treatment clinical trial. The youngest subject in this imaging study was 82 years, and the mean age of the subjects was 85.5 years at the time of the scans; 152 (80%) were cognitively normal, and 38 (20%) were diagnosed with mild cognitive impairment (MCI) at the time of the PiB study.

RESULTS

A high proportion of the cognitively normal subjects (51%) and MCI subjects (68%) were PiB-positive. The APOE*4 allele was more prevalent in PiB-positive than in PiB-negative subjects (30% vs 6%). Measures of memory, language, and attentional functions were worse in PiB-positive than in PiB-negative subjects, when both normal and MCI cases were analyzed together; however, no significant associations were observed within either normal or MCI subject groups alone. There was no relationship between Gb treatment and Aβ deposition as determined by PiB.

INTERPRETATION

The data revealed a 55% prevalence of PiB positivity in nondemented subjects age >80 years and 85% PiB positivity in the APOE*4 nondemented elderly subjects. The findings also showed that long-term exposure to Gb did not affect the prevalence of cerebral Aβ deposition.

Inter-rater reliability of manual and automated region-of-interest delineation for PiB PET

A major challenge in positron emission tomography (PET) amyloid imaging studies of Alzheimer's disease (AD) is the reliable detection of early amyloid deposition in human brain. Manual region-of-interest (ROI) delineation on structural magnetic resonance (MR) images is generally the reference standard for the extraction of count-rate data from PET images, as compared to automated MR-template(s) methods that utilize spatial normalization and a single set of ROIs. The goal of this work was to assess the inter-rater reliability of manual ROI delineation for PiB PET amyloid retention measures and the impact of CSF dilution correction (CSF) on this reliability for data acquired in elderly control (n=5) and AD (n=5) subjects. The intraclass correlation coefficient (ICC) was used to measure reliability. As a secondary goal, ICC scores were also computed for PiB outcome measures obtained by an automated MR-template ROI method and one manual rater; to assess the level of reliability that could be achieved using different processing methods. Fourteen ROIs were evaluated that included anterior cingulate (ACG), precuneus (PRC) and cerebellum (CER). The PiB outcome measures were the volume of distribution (V(T)), summed tissue uptake (SUV), and corresponding ratios that were computed using CER as reference (DVR and SUVR). Substantial reliability (ICC≥0.932) was obtained across 3 manual raters for V(T) and SUV measures when CSF correction was applied across all outcomes and regions and was similar in the absence of CSF correction. The secondary analysis revealed substantial reliability in primary cortical areas between the automated and manual SUV [ICC≥0.979 (ACG/PRC)] and SUVR [ICC≥0.977/0.952 (ACG/PRC)] outcomes. The current study indicates the following rank order among the various reliability results in primary cortical areas and cerebellum (high to low): 1) V(T) or SUV manual delineation, with or without CSF correction; 2) DVR or SUVR manual delineation, with or without CSF correction; 3) SUV automated delineation, with CSF correction; and 4) SUVR automated delineation, with or without CSF correction. The high inter-rater reliability of PiB outcome measures in primary cortical areas (ACG/PRC) is important as reliable methodology is needed for the detection of low levels of amyloid deposition on a cross-sectional basis and small changes in amyloid deposition on a longitudinal basis.