Mark Borgstrom

Detection of small radiation sources: The effect of mode of count‐rate presentation

We used an observer-performance study to compare four different modes of presenting count-rate data from a radiation detector. Observers searched for small, concealed radioactive sources using a hand-held radiation-detector probe. The modes of count-rate presentation were a ratemeter, howler, multichannel scaler, and HRM III. The HRM III calculates the statistical significance of the difference between current and previous count rates and presents the result as an audio signal. We tested six observers with each mode of count-rate presentation, calculated receiver operating characteristic (ROC) curves, and used the areas under the ROC curves to compare the different modes. Observer performance was better with the multichannel scaler and HRM III than with either the ratemeter or the howler. The results suggest that observer performance with devices that use ratemeters or howlers can be enhanced by improving the mode of count-rate presentation.

Coronary Computed Tomography Angiography‐Based Tricuspid Annular Plane Systolic Excursion: Correlation with 2D Echocardiography

Right heart evaluation on coronary computed tomography angiography (CCTA) is underutilized due to nonopacification of the right heart chambers and poor endocardial resolution. We analyzed feasibility and reproducibility of right heart functional analysis by measuring CCTA‐based tricuspid annular plane systolic excursion (CT‐TAPSE) on ECG‐gated CCTA and correlated the results with 2D transthoracic echocardiography (TTE)‐derived TAPSE (Echo‐TAPSE).

Clinical location of the fourth and fifth intercostal spaces as a percent of the length of the sternum

OBJECTIVES To verify accurate placement of the precordial ECG leads by identifying the 4th and 5th intercostal spaces as a function of the length of the sternum. This should decrease the percentage of lead misplacement leading to misdiagnoses. METHODS The population consisted of patients and healthy volunteers. The proposed method compared palpation of the 4th and 5th intercostal spaces to a percentile of the sternal length. Location of the 4th and 5th intercostal space using a simple device was evaluated to assist in proper placement of the precordial leads to obtain accurate diagnosis. RESULTS The location of the 4th and 5th intercostal space is related to the length of the sternum. It is 77% of the sternal length that measures 15cm for the 4th intercostal space. The position of the V1 and V2 electrodes decreases to 57% when the sternal length is 26cm. Similar data was obtained to locate the 5th intercostal space with proper position of V4-V6 electrodes. Tables are provided to facilitate this process. An instrument was designed to measure the 4th and 5th intercostal space as a function of the sternal length. CONCLUSIONS The location of the 4th and 5th intercostal space is identified based on the length of the sternum.

Intraclass correlation: Estimation of the reliability of ratings

The interactive FORTRAN program INTRACORR calculates intraclass correlations; both maximum likelihood and unbiased estimates of the population correlation are calculated. These estimates are available for individual measurements and for the mean of a set of measurements. An option identifies the number of measurements needed to obtain a correlation coefficient of some specified magnitude. The program was written in FORTRAN IV-plus for a Digital Equipment Corporation VAX-I 1/780. Intraclass correlation is a general approach for determining the reliability or agreement of a set of observations. The approach in its various forms uses the meansquare terms generated by a repeated-measures analysis of variance to estimate true score and observed score variability and, provided the proper assumptions are met, gives a measure directly interpretable as a reliability coefficient. Since Fisher (1958) first introduced the notion, it has undergone considerable development by a number of different authors (Bartko, 1966, 1976; Ebel, 1951; Gulliksen, 1950; Horst, 1949; Shrout & Fleiss, 1979; Winer, 1971). Several versions exist, each of which assumes a different linear model under which the variance components are estimated. Three of these versions, explicated by Shrout and Fleiss, are calculated by INTRACORR. A brief description of each of these models is presented in this paper to help the reader evaluate the program. In Modell, each case is rated by a different set of k judges, assumed to be sampled from a larger population of judges. A rating of the jth individual by the ith judge can be represented as follows: x(ij):= m + bG) + w(ij), in this case, m = the overall population mean of ratings, blj) =the effect associated with the jth case, and w(ij) =the combined effect of the ith judge, the interaction of the ith judge with the jth case, and an error component associated with the ijth observation. Model 2, described by Bartko (I 966) and Shrout and Fleiss (1979), is appropriate to the situation in which each of a set of k raters views all n cases. Like Modell, raters are assumed to constitute a random sample from some population of raters. The underlying model for the ith judges rating of the jth case is x(ij) =m + btj) + r(i) +br(ij) +e(ij). Here, m and bG) are defined as before, rei) =the effect of the ith rater, br(i j) := the effect of the ith rater with the jth case, and e(ij) =an

Elevated lactate level predicts intensive care unit admissions, endoscopies and transfusions in patients with acute gastrointestinal bleeding

Background and aims Initial clinical management decision in patients with acute gastrointestinal bleeding (GIB) is often based on identifying high- and low-risk patients. Little is known about the role of lactate measurement in the triage of patients with acute GIB. We intended to assess if lactate on presentation is predictive of need for intervention in patients with acute GIB. Patients and methods We performed a single-center, retrospective, cross-sectional study including patients ≥18 years old presenting to emergency with acute GIB between January 2014 and December 2014. Intensive care unit (ICU) admission, inpatient endoscopy (upper endoscopy and/or colonoscopy), and packed red blood cell (PRBC) transfusion were assessed as outcomes. Analyses included univariate and multivariate logistic regression analyses. Results Of 1,237 patients with acute GIB, 468 (37.8%) had venous lactate on presentation. Of these patients, 165 (35.2%) had an elevated lactate level (>2.0 mmol/L). Patients with an elevated lactate level were more likely to be admitted to ICU than patients with a normal lactate level (adjusted odds ratio [AOR] 2.96, 95% confidence interval [CI] 1.74–5.01; p<0.001). Patients with an elevated lactate level were more likely to receive PRBC transfusion (AOR 3.65, 95% CI 1.76–7.55; p<0.001) and endoscopy (AOR 1.64, 95% CI 1.02–2.65; p=0.04) than patients with a normal lactate level. Conclusion Elevated lactate level predicts the need for ICU admissions, transfusions, and endoscopies in patients with acute GIB. Lactate measurement may be a useful adjunctive test in the triage of patients with acute GIB.

Examining suicidality, bullying, and gun carrying among Latina/o youth over 10 years

Latino/a youth have reported the highest rates of suicide attempts compared to White and African American youth for over 40 years. The data from the Youth Risk Behavior Surveillance System (YRBSS) cross-sectional subsamples of Latino/a youth (N = 13,378) at every year of data collection between 2005 and 2015 were examined for bullying, gun carrying, and suicidality. Results indicate that Latina girls are significantly more likely than boys to make a suicide attempt and report more bullying and more cyberbullying, but are less likely to carry a gun. Being bullied or carrying a gun were significantly associated with greater likelihood of suicide attempt among both boys and girls. Youth who carried a gun overall had higher rates of suicide attempts whether they were bullied or not, whereas youth who did not carry a gun were significantly more likely to attempt suicide if they were bullied. Over the past 10 years, gun carrying has decreased significantly for Latino boys and suicide attempts have decreased significantly for Latina girls. Findings have important implications of considering intersections of race and gender when developing antibullying and suicide prevention strategies. There are important policy implications for considering the mental well-being of youth who are caught carrying guns at school and considering that victimization varies by ethnicity and gender.