Quality Assurance (QA) Assessment for Malaria Rapid Diagnostic Test in Ngoma District, Eastern Province of Rwanda: A cross-sectional prospective study.

Background Currently, malaria rapid diagnostic tests (mRDTs) are increasingly used for the diagnosis of malaria, particularly in communities where microscopy-based diagnosis is not practical. However, the diagnostic accuracy of mRDTs performed by community health workers (CHWs) remains unknown. This study was conducted to determine the accuracy of mRDT results performed by CHWs in Ngoma district, eastern province of Rwanda. Method This was a cross sectional prospective study. A total of 420 blood samples of patients self-reported to CHWs for malaria diagnosis were collected and analyzed by CHWs using mRDT, and quality control tests were performed by using microscopy as a reference test. The study was conducted from 22 April to 08 July 2021. Results Among the 420 patients, 234 (55.71%) were females, and 186 (44.29%) were males. Malaria test positivity was 2.62% by using mRDT and 1.67% by using microscopic tests. The sensitivity and specificity of mRDT were 85.71% and 98.78%, respectively. The negative predictive value, positive predictive value and accuracy of mRDTs were 99.75%, 54.54% and 98.57%, respectively. The sensitivity of mRDT was below the WHO recommended sensitivity (>95%), although the specificity (98.78%) was within the WHO recommended specificity (>=90). There was substantial agreement between the mRDT and malaria microscopic test results, k=0.642. Conclusion mRDTs continue to be an appropriate choice for malaria diagnosis in the absence of microscopy.

Multispectral Imaging Algorithm Predicts Breslow Thickness of Melanoma

Breslow thickness is a major prognostic factor for melanoma. It is based on histopathological evaluation, and thus it is not available to aid clinical decision making at the time of the initial melanoma diagnosis. In this work, we assessed the efficacy of multispectral imaging (MSI) to predict Breslow thickness and developed a classification algorithm to determine optimal safety margins of the melanoma excision. First, we excluded nevi from the analysis with a novel quantitative parameter. Parameter s’ could differentiate nevi from melanomas with a sensitivity of 89.60% and specificity of 88.11%. Following this step, we have categorized melanomas into three different subgroups based on Breslow thickness (≤1 mm, 1–2 mm and >2 mm) with a sensitivity of 78.00% and specificity of 89.00% and a substantial agreement (κ = 0.67; 95% CI, 0.58–0.76). We compared our results to the performance of dermatologists and dermatology residents who assessed dermoscopic and clinical images of these melanomas, and reached a sensitivity of 60.38% and specificity of 80.86% with a moderate agreement (κ = 0.41; 95% CI, 0.39–0.43). Based on our findings, this novel method may help predict the appropriate safety margins for curative melanoma excision.

Performance of the BinaxNOW COVID-19 Antigen Rapid Diagnostic Test for the Detection of SARS-CoV-2

Background: Diagnosis of COVID-19 disease primarily relies on nucleic acid amplification tests (NAAT) that amplify and detect viral RNA in specimens. These methods are expensive and time consuming. Antigen-based rapid diagnostic tests can substantially decrease turnaround time.Methods: We analyzed paired anterior nares swabs collected from symptomatic patients and asymptomatic healthcare workers being tested COVID-19. One swab was used for a direct RDT and the results were compared to NAAT.Results: 89 paired specimens were evaluated. The positive percent agreement (PPA) for the antigen RDT was 68.2%, and the negative percent agreement (NPA) was 98.5%. Despite a low PPA, the Κ statistic was 0.733 indicating substantial agreement with the NAAT result. The median cycle number in paired specimens with concordant results was significantly lower than in discordant specimens (21.3 versus 32.3; P=0.003).Conclusions: The RDT showed modest PPA and high NPA when compared to NAAT. The quick TAT and use of an inexpensive test more frequently could be useful in settings in which results from NAAT testing is delayed.

Quality Assurance (QA) Assessment for Malaria Rapid Diagnostic Test in Ngoma District, Eastern Province of Rwanda: A cross-sectional prospective study

Background Currently, malaria rapid diagnostic tests (mRDTs) are increasingly used for diagnosis of malaria, particularly in community where microscopy-based diagnosis is not practical. However, the diagnostic accuracy of mRDTs performed by the community health workers (CHWs) remains unknown. This study was conducted to determine the accuracy of mRDT results performed by CHWs in Ngoma district, eastern province of Rwanda. Method This was a cross sectional prospective study. 420 blood samples of patients self-reported to CHWs for malaria diagnosis were collected and analyzed by CHWs using mRDT and quality control tests were performed by using microscopy as a reference test. The study was conducted from 22nd April to 08th July, 2021. Results Among the 420 patients, 234 (55.71%) were females and 186 (44.29%) were males. Malaria test positivity was 2.62% by using mRDT and 1.67% by using microscopic test. The sensitivity and specificity of mRDT were 85.71% and 98.78% respectively. Negative predictive value, positive predictive value and accuracy of mRDTs were 99.75%, 54.54% and 98.57% respectively. Sensitivity of mRDT was below the WHO recommended sensitivity (>95%) although the specificity (98.78%) was within the WHO recommended specificity (>=90). There was a substantial agreement between mRDT and malaria microscopic test results, k=0.642. Conclusion mRDTs continue to be an appropriate choice for malaria diagnosis in the absence of microscopy.

256 Impact of physiologically diffuse vs. focal pattern of coronary disease on quantitative flow reserve diagnostic accuracy

Aims Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) disagree in ∼20% of intermediate coronary lesions. The physiological pattern of disease has a significant influence on FFR-iFR discordance. However, if the pattern of disease (diffuse vs. focal) impacts on QFR accuracy and on its agreement with FFR and iFR remains unknown. Methods and results 194 unselected patients with 224 intermediate coronary lesions were investigated with iFR, FFR and QFR. The physiological pattern of disease was independently assessed with iFR Scout pullback in all the cases by two expert interventional cardiologists who were blinded to the clinical presentation, patient characteristics, coronary angiography and QFR results. A predominantly physiologically focal pattern was observed in 81 (36.2%) lesions, whereas a predominantly physiologically diffuse was observed in 143 (63.8%) cases. QFR demonstrated a significant correlation (r = 0.581, P < 0.001) and a substantial agreement with iFR, both in diffuse (AUC = 0.798) and in focal (AUC = 0.812) pattern of disease. Disagreement between QFR and iFR was observed in 51 (22.8%) lesions, consisting of iFR+/QFR − (64.7%) and iFR−/QFR + (35.3%). Notably, the physiological pattern of disease was the only variable significantly associated with iFR/QFR disagreement. In particular, coronary lesions with iFR+/QFR− demonstrated a significantly higher prevalence of predominantly physiologically diffuse pattern of disease compared with the subgroup with iFR−/QFR + [81.3% (26 of 32) vs. 55.6% (10 of 18); P = 0.012]. QFR virtual pullback demonstrated an excellent agreement (83.9%) with iFR Scout pullback in classifying the physiological pattern of disease. Conclusions QFR has a good diagnostic accuracy in assessing myocardial ischemia independently of the pattern of coronary disease. However, the physiological pattern of disease has an influence on the QFR/IFR disagreement, which occurs in ∼20% of the cases. The QFR virtual pullback correctly defined the physiological pattern of disease in the majority of the cases using the iFR pullback as reference.

Quality Assurance (QA) Assessment for Malaria Rapid Diagnostic Test in Ngoma District, Eastern Province of Rwanda: A cross-sectional prospective study.

Background Currently, malaria rapid diagnostic tests (mRDTs) are increasingly used for diagnosis of malaria, particularly in community where microscopy-based diagnosis is not practical. However, the diagnostic accuracy of mRDTs performed by the community health workers (CHWs) remains unknown. This study was conducted to determine the accuracy of mRDT results performed by CHWs in Ngoma district, eastern province of Rwanda. Method This was a cross sectional prospective study. 420 blood samples of patients self-reported to CHWs for malaria diagnosis were collected and analyzed by CHWs using mRDT and quality control tests were performed by using microscopy as a reference test. The study was conducted from 22nd April to 08th July, 2021. Results Among the 420 patients, 234 (55.71%) were females and 186 (44.29%) were males. Malaria test positivity was 2.62% by using mRDT and 1.67% by using microscopic test. The sensitivity and specificity of mRDT were 85.71% and 98.78% respectively. Negative predictive value, positive predictive value and accuracy of mRDTs were 99.75%, 54.54% and 98.57% respectively. Sensitivity of mRDT was below the WHO recommended sensitivity (>95%) although the specificity (98.78%) was within the WHO recommended specificity (>=90). There was a substantial agreement between mRDT and malaria microscopic test results, k=0.642. Conclusion mRDTs continue to be an appropriate choice for malaria diagnosis in the absence of microscopy.

High-resolution pediatric age–specific 18F-FDG PET template: a pilot study in epileptogenic focus localization

Background PET imaging has been widely used in diagnosis of neurological disorders; however, its application to pediatric population is limited due to lacking pediatric age–specific PET template. This study aims to develop a pediatric age–specific PET template (PAPT) and conduct a pilot study of epileptogenic focus localization in pediatric epilepsy. Methods We recruited 130 pediatric patients with epilepsy and 102 age-matched controls who underwent 18F-FDG PET examination. High-resolution PAPT was developed by an iterative nonlinear registration-averaging optimization approach for two age ranges: 6–10 years (n = 17) and 11–18 years (n = 50), respectively. Spatial normalization to the PAPT was evaluated by registration similarities of 35 validation controls, followed by estimation of potential registration biases. In a pilot study, epileptogenic focus was localized by PAPT-based voxel-wise statistical analysis, compared with multi-disciplinary team (MDT) diagnosis, and validated by follow-up of patients who underwent epilepsy surgery. Furthermore, epileptogenic focus localization results were compared among three templates (PAPT, conventional adult template, and a previously reported pediatric linear template). Results Spatial normalization to the PAPT significantly improved registration similarities (P < 0.001), and nearly eliminated regions of potential biases (< 2% of whole brain volume). The PAPT-based epileptogenic focus localization achieved a substantial agreement with MDT diagnosis (Kappa = 0.757), significantly outperforming localization based on the adult template (Kappa = 0.496) and linear template (Kappa = 0.569) (P < 0.05). The PAPT-based localization achieved the highest detection rate (89.2%) and accuracy (80.0%). In postsurgical seizure-free patients (n = 40), the PAPT-based localization also achieved a substantial agreement with resection areas (Kappa = 0.743), and the highest detection rate (95%) and accuracy (80.0%). Conclusion The PAPT can significantly improve spatial normalization and epileptogenic focus localization in pediatric epilepsy. Future pediatric neuroimaging studies can also benefit from the unbiased spatial normalization by PAPT. Trial registration. NCT04725162: https://clinicaltrials.gov/ct2/show/NCT04725162

A comparison of two assessment tools used in overviews of systematic reviews: ROBIS versus AMSTAR-2

Background AMSTAR-2 is a 16-item assessment tool to check the quality of a systematic review and establish whether the most important elements are reported. ROBIS is another assessment tool which was designed to evaluate the level of bias present within a systematic review. Our objective was to compare, contrast and establish both inter-rater reliability and usability of both tools as part of two overviews of systematic reviews. Strictly speaking, one tool assesses methodological quality (AMSTAR-2) and the other assesses risk of bias (ROBIS), but there is considerable overlap between the tools in terms of the signalling questions. Methods Three reviewers independently assessed 31 systematic reviews using both tools. The inter-rater reliability of all sub-sections using each instrument (AMSTAR-2 and ROBIS) was calculated using Gwet’s agreement coefficient (AC1 for unweighted analysis and AC2 for weighted analysis). Results Thirty-one systematic reviews were included. For AMSTAR-2, the median agreement for all questions was 0.61. Eight of the 16 AMSTAR-2 questions had substantial agreement or higher (> 0.61). For ROBIS, the median agreement for all questions was also 0.61. Eleven of the 24 ROBIS questions had substantial agreement or higher. Conclusion ROBIS is an effective tool for assessing risk of bias in systematic reviews and AMSTAR-2 is an effective tool at assessing quality. The median agreement between raters for both tools was identical (0.61). Reviews that included a meta-analysis were easier to rate with ROBIS; however, further developmental work could improve its use in reviews without a formal synthesis. AMSTAR-2 was more straightforward to use; however, more response options would be beneficial.

P076 Sleep Staging Agreement Between Polysomnography and Sleep Profiler in Isolated REM Sleep Behavior Disorder

Purpose Evaluate the sleep staging agreement between polysomnography (PSG) and Sleep Profiler (SP) in patients with suspected isolated REM-sleep-behavior-disorder. Methods Twenty-six patients with reported dream-enactment-behavior (Site1=16, Site2=10; 27% women; age 64±13 years) underwent a diagnostic PSG with simultaneously recorded SP. A registered sleep-technologist at each site performed PSG-staging, while SP was auto-staged and technically reviewed/edited. Across technicians, the initial staging was blinded. Site1 then performed unblinded restaging of PSG=N3(N2) vs. SP=N2(N3) epochs, while Site2 conducted a blinded, carefully-targeted restaging of N3. Statistics included Cohen’s kappa and Chi-square analyses. Results Agreement between SP and Site1 vs. Site2 were significantly different for Wake (kappa:Site1=0.816;Site2=0.650;combined=0.736), stage N1 (kappa:Site1=0.149;Site2=0.228;combined=0.188), stage N2 (kappa:Site1=0.632;Site2=0.718;combined=0.659), stage N3 (kappa:Site1=0.715;Site2=0.368;combined=0.525) and REM (kappa:Site1=0.827;Site2=0.719;combined=0.766)(all P&lt;0.001). After restaging of N3, the kappa values improved at Site1 (unblinded:N2=0.659/N3=0.883) and Site2 (blinded:N2=0.775/N3=0.736)(combined:N2=0.735/N3=0.851). The proportion of PSG-epochs restaged from N3 to N2 was 17% at Sites1 and 38% at Site2 (P&lt;0.001), while Site1 had fewer remaining PSG=N3 vs. SP=N2 conflicts (5.6% vs. 20.8%, P&lt;0.001). Compared to Site2, Site1 had a superior: REM kappa due to fewer SP=N2 disagreements (8.5% vs. 16.8%, P&lt;0.001), and Wake kappa resulting from fewer SP=N1 (6.6 vs. 15.6%, P&lt;0.001) and SP=N2 conflicts (5.9 vs. 12.0%, P&lt;0.001). Conversely, the Site1 N1 kappa was inferior due to greater SP=wake disagreement (41.6% vs. 19.8%, P&lt;0.001). Discussion N3 was excessively stage by both PSG technicians before restaging. At Site1, Wake, N3, and REM had almost-perfect-agreement with SP, while N2 had substantial-agreement. At Site2 and across-site, substantial-agreement was observed for Wake, N2, N3, and REM.

Inter-observer agreement using the LI-RADS version 2018 CT treatment response algorithm in patients with hepatocellular carcinoma treated with conventional transarterial chemoembolization

Aim To determine inter-reader agreement in categorization of imaging features using the Liver Imaging Reporting and Data System (LI-RADS) treatment response (LR-TR) algorithm in patients with hepatocellular carcinoma (HCC) treated with conventional transarterial chemoembolization (cTACE). Methods Two radiologists used the LR-TR algorithm to assess 112 computed tomography (CT) examinations of 102 patients treated with cTACE. The inter-observer agreement in categorization of LR-TR features was assessed using kappa (κ) statistics. Results There was substantial inter-observer agreement between the two reviewers using the LR-TR algorithm (κ = 0.70; 95% CI 0.58–0.81). The two reviewers categorized tumors as non-viable in 37 (33.0%) and 39 (34.8%) of 112 examinations, viable in 58 (51.8%) and 62 (55.4%) examinations, and equivocal in 18 (16.1%) and 11 (9.8%) examinations, respectively. There was almost perfect inter-observer agreement for the LR-TR non-viable category (κ = 0.80; 95% CI 0.68–0.92), substantial agreement for the viable category (κ = 0.78 95% CI 0.67–0.90), and fair agreement for the equivocal category (κ = 0.25; 95% CI 0.02–0.49). Conclusion The LR-TR algorithm conveys high degrees of inter-observer agreement for the assessment of CT imaging features in the viable and non-viable categories. Further refinement of indeterminate features may be necessary to improve the correct categorization of equivocal lesions. Graphic abstract