Accuracy of computer-aided chest X-ray in community-based tuberculosis screening: Lessons from the 2016 Kenya National Tuberculosis Prevalence Survey

Community-based screening for tuberculosis (TB) could improve detection but is resource intensive. We set out to evaluate the accuracy of computer-aided TB screening using digital chest X-ray (CXR) to determine if this approach met target product profiles (TPP) for community-based screening. CXR images from participants in the 2016 Kenya National TB Prevalence Survey were evaluated using CAD4TBv6 (Delft Imaging), giving a probabilistic score for pulmonary TB ranging from 0 (low probability) to 99 (high probability). We constructed a Bayesian latent class model to estimate the accuracy of CAD4TBv6 screening compared to bacteriologically-confirmed TB across CAD4TBv6 threshold cut-offs, incorporating data on Clinical Officer CXR interpretation, participant demographics (age, sex, TB symptoms, previous TB history), and sputum results. We compared model-estimated sensitivity and specificity of CAD4TBv6 to optimum and minimum TPPs. Of 63,050 prevalence survey participants, 61,848 (98%) had analysable CXR images, and 8,966 (14.5%) underwent sputum bacteriological testing; 298 had bacteriologically-confirmed pulmonary TB. Median CAD4TBv6 scores for participants with bacteriologically-confirmed TB were significantly higher (72, IQR: 58–82.75) compared to participants with bacteriologically-negative sputum results (49, IQR: 44–57, p<0.0001). CAD4TBv6 met the optimum TPP; with the threshold set to achieve a mean sensitivity of 95% (optimum TPP), specificity was 83.3%, (95% credible interval [CrI]: 83.0%—83.7%, CAD4TBv6 threshold: 55). There was considerable variation in accuracy by participant characteristics, with older individuals and those with previous TB having lowest specificity. CAD4TBv6 met the optimal TPP for TB community screening. To optimise screening accuracy and efficiency of confirmatory sputum testing, we recommend that an adaptive approach to threshold setting is adopted based on participant characteristics

'If not TB, what could it be?' Chest X-ray findings from the 2016 Kenya Tuberculosis Prevalence Survey

Background: The prevalence of diseases other than tuberculosis (TB) detected during chest X-ray (CXR) screening is unknown in sub-Saharan Africa. This represents a missed opportunity for identification and treatment of potentially significant disease. Our aim was to describe and quantify non-TB abnormalities identified by TB-focused CXR screening during the 2016 Kenya National TB prevalence survey. Methods: We reviewed a random sample of 1140 adult (≥15 years) CXRs classified as “abnormal, suggestive of TB” or “abnormal other” during field interpretation from the TB Prevalence Survey. Each image was read (blinded to field classification and study radiologist read) by two expert radiologists, with images classified into one of four major anatomical categories and primary radiological findings. A third reader resolved discrepancies. Prevalence and 95% confidence intervals of abnormalities diagnosis were estimated. Findings: Cardiomegaly was the most common non-TB abnormality at 259/1123 (23∙1%, 95% CI 20∙6%-25∙6%), while cardiomegaly with features of cardiac failure occurred in 17/1123 (1∙5 %, 95% CI 0.9%-2∙4%). We also identified chronic pulmonary pathology including suspected chronic obstructive pulmonary disease in 3∙2% (95% CI 2∙3%- 4∙4%) and non-specific patterns in 4∙6% (95% CI 3∙5%-6∙0%). Prevalence of active-TB and severe post-TB lung changes was 3∙6% (95% CI 2∙6%- 4∙8%) and 1∙4% (95% CI 0∙8%- 2∙3%) respectively. Interpretation: Based on radiological findings, we identified a wide variety of non-TB abnormalities during population-based TB screening. TB prevalence surveys and active case finding activities using mass CXR offer an opportunity to integrate disease screening efforts

Inadequacy of Headache Management After Subarachnoid Hemorrhage.

BACKGROUND: Headache profoundly affects management of spontaneous subarachnoid hemorrhage but is poorly characterized. OBJECTIVE: To characterize headache after spontaneous subarachnoid hemorrhage. METHODS: Medical records of patients with Hunt and Hess grades I-III subarachnoid hemorrhage admitted from 2011 to 2013 were reviewed. Demographics, clinical and radiographic features, medications, and pain scores were recorded through day 14 after hemorrhage. Headache pain was characterized on the basis of a numeric rating scale and analgesic use. Severe headache was defined as 2 or more days with maximum pain scores of 8 or greater or need for 3 or more different analgesics for 2 or more days. Univariate and multivariable models were used to analyze factors associated with severe headache. RESULTS: Of the 77 patients in the sample, 57% were women; median age was 57 years. Severe headache (73% overall) was associated nonlinearly with Hunt and Hess grade: grade I, 58%; grade II, 88%; and grade III, 56% (P = .01), and with Hijdra score: score 0-10, 56%; score 11-20, 86%; score 21-30, 76% (P = .03). By univariate analysis, patients with low Hijdra scores were less likely to have severe headache (27% vs 57%; P = .02). In a multivariable model, younger age and higher Hijdra score tended to be associated with severe headache. CONCLUSIONS: Headache after spontaneous subarachnoid hemorrhage was often severe, necessitating multiple opioid and nonopioid analgesics. Many patients reported persistent headache and inadequate pain control

Emerging Cycles: Diagenesis caught in the act

Organic biomarker and nannofossil assemblages are used in combination with sedimentary petrology to identify the role of diagenesis for the formation of a rhythmic calcareous succession. A record from the Early Pliocene of the Maldives (Ocean Drilling Program, ODP Leg 115) is presented containing precession and eccentricity cycles expressed as variable aragonite content. Additional sub-Milankovitch cycles are caused by rhythmic precipitation of calcite cement in the lower part of the interval. Comparison with palaeo-productivity indicators (nannofossils, chlorin, total organic carbon) suggests that cementation occurs preferentially in intervals characterized by increasing or decreasing productivity. The coupled variability in productivity and carbonate diagenesis is attributed to the effect of organic matter degradation in the sediment. The observed combination of primary and diagenetic factors hampers the interpretation of the cyclicity on Milankovitch and sub-Milankovitch scales. Diagenetically stable proxies for palaeo-productivity, such as nannofossil assemblage data, were used to distinguish between palaeoclimate and diagenetic influences