Search

Purpose: Research suggests that performance on the Death-Implicit Association Test (D-IAT) converges with explicit indicators of suicide risk (e.g., suicidal ideation, suicidal behaviors). However, the utility of the D-IAT in acute care settings has been questioned given limited studies and inconsistent findings. Additionally, it remains unclear whether the D-IAT incrementally improves the assessment of suicide risk beyond explicit measures. Method: The present study evaluated the validity of the D-IAT in a large sample of psychiatric inpatients who attempted suicide within the past two years (N = 203; M age = 32.93 [SD = 12.61]; 50.7% female; 63.5% White; 22.7% Hispanic/Latino). The D-IAT was scored three ways: (1) conventional D scoring where positive scores indicate stronger implicit associations with death, (2) dichotomized D scores where participants were categorized based on positive or negative D score, and (3) DD scoring, which is a novel procedure that differentiates self-identification with death (Me-DD) from a lack of identification with life (Not Me-DD). Results: D and Not Me-DD were weakly associated with suicide cognitions, hopelessness, suicidal ideation, and wishes to live/die and there were corresponding mean differences based on dichotomized D scores. D and Not Me-DD were also weakly correlated with number of lifetime suicide attempts. Me-DD evidenced fewer significant associations than Not Me-DD suggesting that a lack of association with life may be the central component of D scores. Conclusions: Findings suggest that the D-IAT may not be a useful standalone measure of suicide risk in high-risk populations. [ABSTRACT FROM AUTHOR]

Introduction: Substance use is an established risk factor for suicide attempt. Clarifying the role of substance use in suicide attempts may identify modifiable treatment targets. This study used mixed methods to associate substance use with suicide attempt history and identify pathways through which substance use contributes to attempts. Methods: Study 1 included 213 adult inpatients (n = 127 with substance use disorder [SUD]), who completed assessments of suicide attempt history as well as demographic and clinical suicide risk factors. Study 2 was a narrative analysis of suicide attempt stories described by 20 inpatients diagnosed with SUD. Results: In Study 1, patients with co‐occurring alcohol and drug use disorders reported more actual lifetime suicide attempts than did those without SUD. In addition, alcohol and drug use disorders were independently associated with lifetime suicide attempts after controlling for demographic and clinical confounders. In Study 2, substance use played a role in all suicide attempts through at least one pathway before, during, or after a triggering stressor, or as suicide attempt method. Conclusions: Substances play a role in suicide attempt baseline risk, acute risk and as means. It is important to target chronic and acute substance use in suicide prevention treatment plans. [ABSTRACT FROM AUTHOR]

We present a method for spatial frequency domain data acquisition utilizing a multifrequency synthesis and extraction (MSE) method and binary square wave projection patterns. By illuminating a sample with square wave patterns, multiple spatial frequency components are simultaneously attenuated and can be extracted to determine optical property and depth information. Additionally, binary patterns are projected faster than sinusoids typically used in spatial frequency domain imaging (SFDI), allowing for short (millisecond or less) camera exposure times, and data acquisition speeds an order of magnitude or more greater than conventional SFDI. In cases where sensitivity to superficial layers or scattering is important, the fundamental component from higher frequency square wave patterns can be used. When probing deeper layers, the fundamental and harmonic components from lower frequency square wave patterns can be used. We compared optical property and depth penetration results extracted using square waves to those obtained using sinusoidal patterns on an in vivo human forearm and absorbing tube phantom, respectively. Absorption and reduced scattering coefficient values agree with conventional SFDI to within 1% using both high frequency (fundamental) and low frequency (fundamental and harmonic) spatial frequencies. Depth penetration reflectance values also agree to within 1% of conventional SFDI. [ABSTRACT FROM AUTHOR]

There is a need for cost effective, quantitative tissue spectroscopy and imaging systems in clinical diagnostics and pre-clinical biomedical research. A platform that utilizes a commercially available light-emitting diode (LED) based projector, cameras, and scaled Monte Carlo model for calculating tissue optical properties is presented. These components are put together to perform spatial frequency domain imaging (SFDI), a model-based reflectance technique that measures and maps absorption coefficients (µa) and reduced scattering coefficients (µs') in thick tissue such as skin or brain. We validate the performance of the flexible LED and modulation element (FLaME) system at 460, 530, and 632 nm across a range of physiologically relevant µa values (0.07 to 1.5 mm-1) in tissue-simulating intralipid phantoms, showing an overall accuracy within 11% of spectrophotometer values for µa and 3% for µs'. Comparison of oxy- and total hemoglobin fits between the FLaME system and a spectrophotometer (450 to 1000 nm) is differed by 3%. Finally, we acquire optical property maps of a mouse brain in vivo with and without an overlying saline well. These results demonstrate the potential of FLaME to perform tissue optical property mapping in visible spectral regions and highlight how the optical clearing effect of saline is correlated to a decrease in µs' of the skull. [ABSTRACT FROM AUTHOR]

The feasibility of spatial frequency domain imaging (SFDI) for breast surgical margin assessment was evaluated in tissue-simulating phantoms and in fully intact lumpectomy specimens at the time of surgery. Phantom data was evaluated according to contrast-detail resolution, quantitative accuracy and model-data goodness of fit, where optical parameters were estimated by minimizing the residual sum of squares between the measured modulation amplitude and its solutions, modeled according to diffusion and scaled-Monte Carlo simulations. In contrast-detail phantoms, a 1.25-mm-diameter surface inclusion was detectable for scattering contrast >28%; a fraction of this scattering contrast (7%) was detectable for a 10 mm surface inclusion and at least 33% scattering contrast was detected up to 1.5 mm below the phantom surface, a probing depth relevant to breast surgical margin assessment. Recovered hemoglobin concentrations were insensitive to changes in scattering, except for overestimation at visible wavelengths for total hemoglobin concentrations <15 μM. The scattering amplitude increased linearly with scattering concentration, but the scattering slope depended on both the particle size and number density. Goodness of fit was comparable for the diffusion and scaled-Monte Carlo models of transport in spatially modulated, near-infrared reflectance acquired from 47 lumpectomy tissues, but recovered absorption parameters varied more linearly with expected hemoglobin concentration in liquid phantoms for the scaled-Monte Carlo forward model. SFDI could potentially reduce the high secondary excision rate associated with breast conserving surgery; its clinical translation further requires reduced image reconstruction time and smart inking strategies. [ABSTRACT FROM AUTHOR]