Technical Adequacy of Fully Automated Artificial Intelligence Body Composition Tools: Assessment in a Heterogeneous Sample of External CT Examinations.

BACKGROUND. Clinically usable artificial intelligence (AI) tools analyzing imaging studies should be robust to expected variations in study parameters. OBJECTIVE. The purposes of this study were to assess the technical adequacy of a set of automated AI abdominal CT body composition tools in a heterogeneous sample of external CT examinations performed outside of the authors' hospital system and to explore possible causes of tool failure. METHODS. This retrospective study included 8949 patients (4256 men, 4693 women; mean age, 55.5 ± 15.9 years) who underwent 11,699 abdominal CT examinations performed at 777 unique external institutions with 83 unique scanner models from six manufacturers with images subsequently transferred to the local PACS for clinical purposes. Three independent automated AI tools were deployed to assess body composition (bone attenuation, amount and attenuation of muscle, amount of visceral and sub-cutaneous fat). One axial series per examination was evaluated. Technical adequacy was defined as tool output values within empirically derived reference ranges. Failures (i.e., tool output outside of reference range) were reviewed to identify possible causes. RESULTS. All three tools were technically adequate in 11,431 of 11,699 (97.7%) examinations. At least one tool failed in 268 (2.3%) of the examinations. Individual adequacy rates were 97.8% for the bone tool, 99.1% for the muscle tool, and 98.9% for the fat tool. A single type of image processing error (anisometry error, due to incorrect DICOM header voxel dimension information) accounted for 81 of 92 (88.0%) examinations in which all three tools failed, and all three tools failed whenever this error occurred. Anisometry error was the most common specific cause of failure of all tools (bone, 31.6%; muscle, 81.0%; fat, 62.8%). A total of 79 of 81 (97.5%) anisometry errors occurred on scanners from a single manufacturer; 80 of 81 (98.8%) occurred on the same scanner model. No cause of failure was identified for 59.4% of failures of the bone tool, 16.0% of failures of the muscle tool, or 34.9% of failures of the fat tool. CONCLUSION. The automated AI body composition tools had high technical adequacy rates in a heterogeneous sample of external CT examinations, supporting the generalizability of the tools and their potential for broad use. CLINICAL IMPACT. Certain causes of AI tool failure related to technical factors may be largely preventable through use of proper acquisition and reconstruction protocols.

Chemical genetics and cereal starch metabolism: structural basis of the non-covalent and covalent inhibition of barley ß-amylase.

There are major issues regarding the proposed pathway for starch degradation in germinating cereal grain. Given the commercial importance but genetic intractability of the problem, we have embarked on a program of chemical genetics studies to identify and dissect the pathway and regulation of starch degradation in germinating barley grains. As a precursor to in vivo studies, here we report systematic analysis of the reversible and irreversible inhibition of the major ß-amylase of the grain endosperm (BMY1). The molecular basis of inhibitor action was defined through high resolution X-ray crystallography studies of unliganded barley ß-amylase, as well as its complexes with glycone site binder disaccharide iminosugar G1M, irreversible inhibitors α-epoxypropyl and α-epoxybutyl glucosides, which target the enzyme's catalytic residues, and the aglycone site binders acarbose and α-cyclodextrin.

Rapid sequence airway vs rapid sequence intubation in a simulated trauma airway by flight crew.

BACKGROUND: Rapid sequence airway (RSA) utilizes rapid sequence intubation (RSI) pharmacology followed by the placement of an extraglottic airway without direct laryngoscopy. STUDY OBJECTIVE: To evaluate the difference in time to airway placement and lowest oxygen saturations in a simulated trauma patient using RSI or RSA with a Laryngeal Mask Airway-Supreme (LMAS). METHODS: This randomized, prospective, non-blinded, IRB-approved observational study used a SimMan human simulator in an ambulance. FC were randomly assigned to initially manage the patient with RSI or RSA. They then completed the same scenario with the other modality to serve as their own control. Trained assistants performed directed tasks. SimMan had an initial grade III view and desaturated along a standardized curve until intubation, LMAS, or bag-valve-mask ventilation (BVMV) was initiated. When BVMV was used, oxygen saturation increased along a standardized curve. The simulator's airway converted to a grade II view after the first attempt if difficult airway maneuvers were applied. Time, oxygen saturation, number of attempts and back-up airway placement were recorded. RESULTS: Nineteen FC completed both paired modalities. Paired T-test was used for statistical analysis. Average time to secure the airway was 145 s shorter in the RSA group (95% CI: 100.4-189.7). Lowest oxygen saturation was 4.8% higher (95% CI: 2.8-6.8) in the RSA group. During RSI, FC placed a back-up airway 47% of the time. CONCLUSION: In a simulated moderately difficult trauma airway managed by FC, RSA results in a significantly shorter time to secure the airway and less hypoxemia compared to RSI.

Acetazolamide fails to decrease pulmonary artery pressure at high altitude in partially acclimatized humans.

In this randomized, double-blind placebo controlled trial our objectives were to determine if acetazolamide is capable of preventing high altitude pulmonary edema (HAPE) in trekkers traveling between 4250 m (Pheriche)\4350 m (Dingboche) and 5000 m (Lobuje) in Nepal; to determine if acetazolamide decreases pulmonary artery systolic pressures (PASP) at high altitude; and to determine if there is an association with PASP and signs and symptoms of HAPE. Participants received either acetazolamide 250 mg PO BID or placebo at Pheriche\Dingboche and were reassessed in Lobuje. The Lake Louise Consensus Criteria were used for the diagnosis of HAPE, and cardiac ultrasonography was used to measure the velocity of tricuspid regurgitation and estimate PASP. Complete measurements were performed on 339 of the 364 subjects (164 in the placebo group, 175 in the acetazolamide group). No cases of HAPE were observed in either study group nor were differences in the signs and symptoms of HAPE found between the two groups. Mean PASP values did not differ significantly between the acetazolamide and placebo groups (31.3 and 32.6 mmHg, respectively). An increasing number of signs and symptoms of HAPE was associated with elevated PASP (p < 0.01). The efficacy of acetazolamide against acute mountain sickness, however, was significant with a 21.9% incidence in the placebo group compared to 10.2 % in the acetazolamide group (p < 0.01). Given the lack of cases of HAPE in either group, we can draw no conclusions about the efficacy of acetazolamide in preventing HAPE, but the absence of effect on PASP suggests that any effect may be minor possibly owing to partial acclimatization during the trek up to 4200 m.

Language used in Lake Louise Scoring System underestimates symptoms of acute mountain sickness in 4- to 11-year-old children.

The Lake Louise Scoring System (LLSS) was designed to evaluate adults for symptoms of acute mountain sickness (AMS). The language used in the LLSS may be too complex for young children to comprehend. This study evaluates if age-appropriate language alters the results of AMS diagnostic scores in 4- to 11-yr-old children. With parental help, subjects completed the LLSS and an equivalent Lake Louise Age-Adjusted Symptom Score (LLAASS) daily for 3 days. Measurements were made at 1605 m, in the subjects' homes, without any altitude change. Equivalent questions between the two surveys were assessed for agreement on the day when the most symptoms were recorded for each question. Thirty-seven children (19 girls), ages 4 to 11 yr (mean age 7.4 +/- 2.3 yr) completed the study. Kappa values: headache (kappa = 0.22), gastrointestinal (kappa = 0.34), fatigue (kappa = 0.88), dizziness (kappa = 0.65), and sleep (kappa = 0.88) ranged from fair to very good. The LLAASS resulted in higher mean symptom scores (1.14 +/- 0.98) compared to LLSS questions (0.61 +/- 0.82) (p < 0.01). The AMS diagnostic threshold was reached in 9% (95% CI, 4-16) of measurements using the LLAASS and 4.5% (95% CI, 1.5-10) with the LLSS. The LLSS results in reporting of fewer AMS symptoms in this population when compared with a diagnostic tool using age-appropriate language and/or visual representations. Age-appropriate communication must be used to assess AMS, particularly for headache (the key symptom of AMS) and gastrointestinal symptoms. Young children report symptoms of AMS at baseline without altitude gain; therefore, the AMS diagnostic threshold in this population may require modification.