A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / This investigation assessed the diagnostic accuracy of thin-slice (1mm) axial Magnetic Resonance Imaging (MRI) in the detection and classification of meniscal tears. Meniscal injuries are a common reason for knee pain and the use of MRI has become standard in their assessment. However, the classification of tears and not merely the detection of lesions has become increasingly important to surgeons in deciding between surgery and conservative management. There is a growing body of literature examining the utility of axial MR images in aiding radiologists to more accurately describe and classify morphological characteristics of meniscus tears. However, the thick- slice (4-5mm) axial sequences utilized at many institutions typically only produce 1-2 images on which the menisci can be visualized, which does not provide the required detail to accurately describe the morphological characteristics of meniscal lesions. This study adds to the growing body of literature examining the diagnostic capabilities of MRI with TSAi to accurately describe meniscal tear morphologies. Imaging reports from 107 patients with clinically suspected meniscus injuries who underwent MRI with thin-slice axial imaging were compared to arthroscopic findings using receiver operating characteris (ROC) analysis to assess the diagnostic accuracy of MRI with thin- slice axial imaging (TSAi). The sensitivity and specificity of MRI with TSAi for meniscal tear detection were found to be 91% and 37.5% respectively. Furthermore, MRI with TSAi was highly specific for bucket handle (98.5%) and root ligament tears (94.1%). The findings of our investigation indicate that MRI with TSAi may assist surgeons in determining the need for operative versus conservative management. MRI with TSAi may be particularly helpful in the case of root tears, which were not as readily identified with traditional MRI techniques and often require surgical intervention due to morbidity associated with unrepaired root tears.

Loop-mediated isothermal DNA amplification (LAMP) are currently used as standalone diagnostic test for C. difficile infection (CDI). We assessed the diagnostic accuracy of LAMP for the diagnosis of CDI. We searched 5 databases to identify studies that compared LAMP with culture cytotoxicity neutralization assay or anaerobic toxigenic culture (TC) of C. difficile. We used the random-effects model to calculate pooled sensitivities, specificities, diagnostic odds ratios and their 95% confidence intervals (CIs). The search of the databases yielded 16 studies (6,979 samples) that met inclusion criteria. When TC was used as the gold standard (6,572 samples), bivariate analysis yielded a mean sensitivity of 0.95 (95%CI, 0.93-0.97; I2 = 67.4) and a mean specificity of 0.99 (95%CI, 0.96-1.00; I2 = 97.0). LAMP is a useful diagnostic tool with high sensitivity and specificity for detecting CDI. The results should however be interpreted only in the presence of clinical suspicion and symptoms of CDI. / Revisión por pares

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This thesis presents the results of three complementary studies which were carried out to evaluate the accuracy of diagnostic tests for Salmonella in pigs. First, a research synthesis method approach, which included a systematic review, meta-analysis and meta-regression, was used to map out existing primary research investigating the accuracy of bacterial culture, antibody or antigen -capture ELISA, and PCR for Salmonella in pigs under field conditions.. Large statistical variability, limited methodological soundness and reporting precluded a quantitative synthesis of findings from multiple studies. The meta-regression identified significant factors, such as variations in test protocols, which explained much of the variability of reported estimates of test accuracy. The need for consistent use of a standard reference test is essential to ensure comparability of results generated in future studies.<p> In the second study, the accuracy of a bacterial culture, real-time (RT) PCR, and a mix-ELISA for Salmonella in were evaluated in western Canadian nursery and grow-finish pigs using traditional and Bayesian statistical methods. Ten farrow-to-finish pig farms from Alberta and Saskatchewan were purposively selected based on their presumptive Salmonella status. Bacteriological culture, RT-PCR and a mix-ELISA were performed on feces and blood samples collected from grow-finish (n=294) pigs and pens. Bayesian estimates of test sensitivity (Se) and specificity (Sp) at the individual pig level were similar to traditional statistical estimates. Sensitivity of culture and RT-PCR ranged from 65-75%, PCR Sp was 98-99% and ELISA Se and Sp at a cutoff of OD¡Ý20% ranged from 59-63% and 84-87%, respectively. In the third study, Salmonella serovar distribution and risk factors for Salmonella shedding were investigated in breeding, nursery, and grow-finish pigs using the same 10 herds. Among 418 Salmonella isolates, most common serovars were Derby (28.5%), Typhimurium, var. Copenhagen (19.1%), and Putten (11.8%). More Salmonella were detected in pooled pen than individual pig samples, confirming that the use of pooled samples is more effective for detecting the full range of serovars that may be present on Canadian pig farms. Sows shed significantly more Salmonella than nursery or grow to finish pigs, suggesting that the breeding herd is an important source of Salmonella persistence. Pelleted feed and nose-to-nose pig contact through pens were also associated with increased Salmonella prevalence, indicating that these factors are relevant as control targets.<p> The main advantages of research synthesis methods are increased power and precision in effect estimates and identification knowledge gaps and areas requiring further research. Bayesian methods for evaluating test accuracy are useful when there is no known "gold standard", which is often the case for zoonotic and food-borne pathogens. Both research synthesis and Bayesian methods are valuable tools for evaluating diagnostic test accuracy and should be more frequently used when developing monitoring and control programs in food safety.

This thesis presents the results of three complementary studies which were carried out to evaluate the accuracy of diagnostic tests for Salmonella in pigs. First, a research synthesis method approach, which included a systematic review, meta-analysis and meta-regression, was used to map out existing primary research investigating the accuracy of bacterial culture, antibody or antigen -capture ELISA, and PCR for Salmonella in pigs under field conditions.. Large statistical variability, limited methodological soundness and reporting precluded a quantitative synthesis of findings from multiple studies. The meta-regression identified significant factors, such as variations in test protocols, which explained much of the variability of reported estimates of test accuracy. The need for consistent use of a standard reference test is essential to ensure comparability of results generated in future studies.<p> In the second study, the accuracy of a bacterial culture, real-time (RT) PCR, and a mix-ELISA for Salmonella in were evaluated in western Canadian nursery and grow-finish pigs using traditional and Bayesian statistical methods. Ten farrow-to-finish pig farms from Alberta and Saskatchewan were purposively selected based on their presumptive Salmonella status. Bacteriological culture, RT-PCR and a mix-ELISA were performed on feces and blood samples collected from grow-finish (n=294) pigs and pens. Bayesian estimates of test sensitivity (Se) and specificity (Sp) at the individual pig level were similar to traditional statistical estimates. Sensitivity of culture and RT-PCR ranged from 65-75%, PCR Sp was 98-99% and ELISA Se and Sp at a cutoff of OD¡Ý20% ranged from 59-63% and 84-87%, respectively. In the third study, Salmonella serovar distribution and risk factors for Salmonella shedding were investigated in breeding, nursery, and grow-finish pigs using the same 10 herds. Among 418 Salmonella isolates, most common serovars were Derby (28.5%), Typhimurium, var. Copenhagen (19.1%), and Putten (11.8%). More Salmonella were detected in pooled pen than individual pig samples, confirming that the use of pooled samples is more effective for detecting the full range of serovars that may be present on Canadian pig farms. Sows shed significantly more Salmonella than nursery or grow to finish pigs, suggesting that the breeding herd is an important source of Salmonella persistence. Pelleted feed and nose-to-nose pig contact through pens were also associated with increased Salmonella prevalence, indicating that these factors are relevant as control targets.<p> The main advantages of research synthesis methods are increased power and precision in effect estimates and identification knowledge gaps and areas requiring further research. Bayesian methods for evaluating test accuracy are useful when there is no known "gold standard", which is often the case for zoonotic and food-borne pathogens. Both research synthesis and Bayesian methods are valuable tools for evaluating diagnostic test accuracy and should be more frequently used when developing monitoring and control programs in food safety.

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Background: Malaria is a major world health issue and its continued burden is due, in part, to difficulties in the diagnosis of the illness. The World Health Organization recommends confirmatory testing using microscopy-based techniques or rapid diagnostic tests (RDT) for all cases of suspected malaria. In regions where Plasmodium species are indigenous, there are multiple etiologies of fever leading to misdiagnoses, especially in populations where HIV is prevalent and children. To determine the frequency of malaria infection in febrile patients over an 8-month period at the Regional Hospital in Bamenda, Cameroon, we evaluated the clinical efficacy of the Flourescence and Staining Technology (FAST) Malaria stain and ParaLens AdvanceTM microscopy system (FM) and compared it with conventional bright field microscopy and Giemsa stain (GS). Methods: Peripheral blood samples from 522 patients with a clinical diagnosis of "suspected malaria" were evaluated using GS and FM methods. A nested PCR assay was the gold standard to compare the two methods. PCR positivity, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were determined. Results: Four hundred ninety nine samples were included in the final analysis. Of these, 30 were positive via PCR (6.01%) with a mean PPV of 19.62% and 27.99% for GS and FM, respectively. The mean NPV was 95.01% and 95.28% for GS and FM, respectively. Sensitivity was 26.67% in both groups and specificity was 92.78% and 96.21% for GS and FM, respectively. An increased level of diagnostic discrepancy was observed between technicians based upon skill level using GS, which was not seen with FM. Conclusions: The frequency of malarial infections confirmed via PCR among patients presenting with fever and other symptoms of malaria was dramatically lower than that anticipated based upon physicians' clinical suspicions. A correlation between technician skill and accuracy of malaria diagnosis using GS was observed that was less pronounced using FM. Additionally, FM increased the specificity and improved the PPV, suggesting this relatively low cost approach could be useful in resource-limited environments. Anecdotally, physicians were reluctant to not treat all patients symptomatically before results were known and in spite of a negative microscopic diagnosis, highlighting the need for further physician education to avoid this practice of overtreatment. A larger study in an area with a known high prevalence is being planned to compare the two microscopy methods against available RDTs.

>Magister Scientiae - MSc / Periapical lesions are fairly common pathology associated with the apex of a non-vital tooth. Some chronic lesions develop without an acute phase with no recollection of previous symptoms. It is known that maxillary odontogenic infections can breach the sinus floor with succeeding complications. Pantomography, a widespread conventional radiographic technique, provides a generalized view of the maxillofacial region. Advanced modalities like CBCT may facilitate in navigating complex anatomy, which would otherwise be obscured.

No description available.

BACKGROUND: Clinical investigation of shoulder injuries commonly utilizes visual evaluation of scapular movement to determine if abnormal or asymmetrical movements are related to the injury. To date, the intrarater reliability and diagnostic accuracy of visual evaluation of scapular movement among physical therapists are not known. PURPOSE: The aims of this study were to determine the clinical reliability and diagnostic accuracy of physical therapists visual evaluation of scapulohumeral movements when used to diagnose shoulder impairment. STUDY DESIGN: University based laboratory and an internet based survey. METHODS: Thirty-three physical therapists and 12 patient participants participated in this study. Reliability was measured as percent agreement and using the free marginal kappa statistic (κ) and Cronbach's alpha (α) for interrater and intrarater reliability respectively. Diagnostic accuracy variables such as sensitivity, specificity, likelihood ratios were calculated from contingency table analysis. RESULTS: Visual evaluation yielded the following (95% CI): diagnostic accuracy 49.5%, specificity 60% (56 - 64), and sensitivity 35% (29 - 41), positive and negative likelihood ratios were 0.87 (0.66 - 1.14) and 1.09 (0.92 - 1.27) respectively. Percent agreements of evaluation findings between sessions for static and dynamic symmetry were 69% and 68%, respectively. The alpha statistics for static and dynamic symmetry were both 0.51. Percentage agreement in determining the injured shoulder was 59%, with an alpha statistic of 0.35. CONCLUSION: Visual evaluation of scapular movements, without additional clinical information, demonstrated a poor to fair reliability and poor to fair diagnostic accuracy. CLINICAL RELEVANCE: The clinical utility of the use of isolated visual scapular evaluation is cautioned. More reliable and valid objective measures are needed for diagnosing shoulder impairment. LEVEL OF EVIDENCE: 2b, Exploratory cohort study.