False Negative Reports Research Articles

Infective endocarditis: Role of molecular techniques in early diagnosis.

Infective endocarditis (IE), a heart valve infection primarily caused by bacteria such as streptococci or staphylococci, causes significant morbidity and mortality. Despite the long-term use of broad-spectrum antimicrobials, the infection is often difficult to manage. The latest diagnostic modalities for IE are discussed in this study. Blood culture use in pathogen identification can lead to loss of precious time as well as generation of false negative reports. The first steps in diagnosis are blood cultures and echocardiography, but molecular techniques can be extremely useful and may be used for an accurate and early diagnosis.

Evaluation of pooling of samples for testing SARS-CoV- 2 for mass screening of COVID-19

BackgroundThe current pandemic of the SARS-CoV-2 virus, widely known as COVID-19, has affected millions of people around the world. The World Health Organization (WHO) has recommended vigorous testing to differentiate SARS-CoV-2 from other respiratory infections to aid in guiding appropriate care and management. Situations like this have demanded robust testing strategies and pooled testing of samples for SARS-CoV-2 virus has provided the solution to mass screening of people for COVID-19. A pooled testing strategy can be very effective in testing when resources are limited, yet it comes with its own limitations. These benefits and limitations need critical consideration when it comes to testing highly infectious diseases like COVID-19.MethodsThis study evaluated the pooled testing of nasopharyngeal swabs for SARS-COV-2 by comparing the sensitivity of individual sample testing with 4-and 8-pool sample testing. Median cycle threshold (Ct) values were compared, and the precision of pooled testing was assessed through an inter- and intra-assay of pooled samples. Coefficient of variance was calculated for inter- and intra-assay variability.ResultsThe sensitivity becomes considerably lower when the samples are pooled. There is a high percentage of false negative reports with larger sample pool size and when the patient viral load is low or weak positive samples. High variability was seen in the intra- and inter-assay, especially among weak positive samples and when more number of samples are pooled together.ConclusionAs COVID − 19 infection numbers and need for testing remain high, we must meticulously evaluate the testing strategy for each country depending on its testing capacity, infrastructure, economic strength, and need to determine the optimal balance on the cost-effective strategy of resource saving and risk/ cost of missing positive patients.

Relevance of Invasive Testing in Era of Non-Invasive Testing for Prenatal Chromosomal Abnormalities

Prenatal screening for chromosomal abnormalities has two components i.e. prenatal screening (maternal serum screening and cell-free fetal DNA screening) and prenatal diagnosis (chorionic villus sampling, amniocentesis, and cordocentesis). Prenatal testing in the past decade is evolving towards non-invasive methods to determine the chromosome abnormality disorders in the fetus without incurring the risk of miscarriage. Conventional tools for prenatal screening included maternal age, maternal serum markers, ultrasound marker (nuchal thickness), and their combinations. With the increased risk of screening test patients were offered diagnostic tests (chorionic villus sampling, amniocentesis, and cordocentesis). After the availability of noninvasive prenatal tests for commercial use in 2011, a great marketing drive is there to establish it as a master tool for prenatal testing. However various society guidelines i.e. ACOG, RCOG, and ISUOG have clearly stated that cell-free fetal DNA based noninvasive prenatal tests is a screening test, not a diagnostic test. In the succeeding paragraph, we will review current trends in the field of cell-free fetal DNA noninvasive prenatal tests and the relevance of invasive testing in the context of noninvasive prenatal tests. Noninvasive prenatal tests does not entirely replace invasive prenatal testing procedures. Positive noninvasive prenatal tests findings must be confirmed by diagnostic tests based on an invasive sample source, mainly chorionic villus sampling or amniocentesis due to false positive and false negative reports of cell-free fetal DNA based tests. Continuing research and development efforts are focused on overriding noninvasive prenatal tests limitations. Recent studies show that procedure-associated risks in the case of prenatal invasive testing are very low as compared to previous studies. Prenatal invasive testing will remain as the backbone of prenatal diagnostic testing until the limitation of noninvasive prenatal tests is overcome.

Comparison of self-reports and biomedical measurements on hypertension and diabetes among older adults in China

BackgroundResearchers interested in the effects of health on various life outcomes often use self-reported health and disease as an indicator of true, underlying health status. However, the validity of reporting is questionable as it relies on the awareness, recall bias and social desirability. Accordingly, biomedical test is generally regarded as a more precise indication of the disease.MethodsUsing data from the third wave of China Health and Retirement Longitudinal Study (CHARLS), we selected individuals aged 40–85 years old who participated in both health interview survey and biomedical test. Sensitivity, specificity, false negative reporting and false positive reporting were used as measurements of (dis) agreement or (in) validity, and binary and multinomial logistic regression were used to estimate under-report or over-report of hypertension and diabetes.ResultsSelf-reported hypertension and diabetes showed low sensitivity (73.24 and 49.21%, respectively) but high specificity (93.61 and 98.05%, respectively). False positive reporting of hypertension and diabetes were 3.97 and 1.67%, while false negative reports were extremely high at 10.14 and 7.38%. Educational attainment, hukou, age and gender affected both group-specific error and overall error with some differences in their magnitude and directions.ConclusionSelf-reported conditions underestimate the disease burden of hypertension and diabetes in China. Adding objective measurements into social survey could improve data accuracy and allow better understanding of socioeconomic inequalities in health. Furthermore, there is an urgent need to provide basic health education and physical examination to citizens, and promote the use of healthcare to lower the incidence and unawareness of disease in China.

Negative 11C-choline PET/computed tomography imaging in restaging of patients with prostate cancer with serum prostate-specific antigen values >20 ng/mL.

Several studies have reported about the performance of C-choline-PET/computed tomography (CT) (choline) in patients with biochemical recurrent (BCR) prostate cancer, but there is a lack of information regarding negative choline in the same clinical setting. Our aim was to retrospectively analyse negative choline in a cohort of BCR-patients with high prostate-specific antigen (PSA). We retrospectively analysed all choline-scans performed at two high-volume imaging centres between 2005 and 2018, selecting those of interest according to the following inclusion criteria: (1) proven prostate cancer treated either with radical prostatectomy or primary external beam radiation therapy (EBRT), (2) BCR after radical prostatectomy or EBRT, (3) PSA serum values >20 ng/mL at the time of scan and (4) scan reported as negative for active disease. Overall, among 5792 scans performed for BCR-prostate cancer, 14 matched the inclusion criteria and were classified as follows: 5/14(36%) inaccurate reports, 3/14(21%) questionable underestimation of positive findings, originally described as unclear, 6/14(43%) negatives. Choline showed a high detection rate in BCR-prostate cancer patients with PSA >20 ng/mL. Although negative reports can be found in this clinical setting, in our review various disease-relevant findings were identified in more than half of the cases originally reported as negative warranting a double reading in such cases to avoid false-negative reports.

Errors in Survey Reporting and Imputation and Their Effects on Estimates of Food Stamp Program Participation

Abstract Accurately measuring government benefit receipt in household surveys is necessary when studying disadvantaged populations and the programs that serve them. The Food Stamp Program is especially important given its size and recent growth. To validate survey reports, we use administrative data on participation in two states linked to the American Community Survey (ACS), the Current Population Survey (CPS), and the Survey of Income and Program Participation (SIPP). We find that 23 percent of true food stamp recipient households do not report receipt in the SIPP, 35 percent in the ACS, and fully 50 percent in the CPS. A substantial number of true non-recipients are also recorded as recipients, especially in the SIPP. We examine reasons for these errors including imputation, an important source of error. Both false negative and false positive reports vary with household characteristics, implying complicated biases in multivariate analyses, such as regressions. We then directly examine biases in common survey-based estimates of program receipt by comparing them to estimates from our combined administrative and survey data. We find that the survey estimates understate participation among single parents, non-whites, and low-income households, and also lead to errors in multiple program receipt, and time and age patterns of receipt.

Data From Web-Based Questionnaires Were Valid for Gestational Diabetes and Preeclampsia, but Not Gestational Hypertension

ObjectivesWe aimed to validate Web-based questionnaires for the common pregnancy complications gestational diabetes, gestational hypertension, and preeclampsia. Study Design and SettingWe included 1,809 women participating in the PRegnancy and Infant DEvelopment (PRIDE) Study who delivered in 2012–2017, for whom relevant data were complete. Sensitivity, specificity, and positive and negative predictive values of self-reported diagnoses of gestational diabetes, gestational hypertension, and preeclampsia were determined using obstetric records as reference standard. Furthermore, we assessed whether maternal characteristics affected disagreement between questionnaires and obstetric record. ResultsFor gestational diabetes and preeclampsia, we observed very few false-positive and false-negative reports, yielding sensitivities of 93% (95% confidence interval [CI] 86–100) and 88% (95% CI 79–98), respectively, and specificities of 100%. Depending on the definition of gestational hypertension, sensitivity and positive predictive values ranged from 62% to 89% and 53% to 64%, respectively. Disagreement on gestational hypertension was associated with prepregnancy overweight and multiparity. ConclusionSelf-reports of gestational diabetes and preeclampsia in Web-based questionnaires were valid, but the validity of gestational hypertension seemed to be lower because of relatively high numbers of false-positive reports. However, it is questionable whether an appropriate reference standard exists to validate this pregnancy complication.

NOTIFy (non-toxic lyophilized field)-FISH for the identification of biological agents by Fluorescence in situ Hybridization.

The rapid and reliable diagnostics of highly pathogenic bacteria under restricted field conditions poses one of the major challenges to medical biodefense, especially since false positive or false negative reports might have far-reaching consequences. Fluorescence in situ hybridization (FISH) has the potential to represent a powerful microscopy-based addition to the existing molecular-based diagnostic toolbox. In this study, we developed a set of FISH-probes for the fast, matrix independent and simultaneous detection of thirteen highly pathogenic bacteria in different environmental and clinical sample matrices. Furthermore, we substituted formamide, a routinely used chemical that is toxic and volatile, by non-toxic urea. This will facilitate the application of FISH under resource limited field laboratory conditions. We demonstrate that hybridizations performed with urea show the same specificity and comparable signal intensities for the FISH-probes used in this study. To further simplify the use of FISH in the field, we lyophilized the reagents needed for FISH. The signal intensities obtained with these lyophilized reagents are comparable to freshly prepared reagents even after storage for a month at room temperature. Finally, we show that by the use of non-toxic lyophilized field (NOTIFy)-FISH, specific detection of microorganisms with simple and easily transportable equipment is possible in the field.

DdPCR: a more accurate tool for SARS-CoV-2 detection in low viral load specimens

ABSTRACT Quantitative real time PCR (RT-PCR) is widely used as the gold standard for clinical detection of SARS-CoV-2. However, due to the low viral load specimens and the limitations of RT-PCR, significant numbers of false negative reports are inevitable, which results in failure to timely diagnose, cut off transmission, and assess discharge criteria. To improve this situation, an optimized droplet digital PCR (ddPCR) was used for detection of SARS-CoV-2, which showed that the limit of detection of ddPCR is significantly lower than that of RT-PCR. We further explored the feasibility of ddPCR to detect SARS-CoV-2 RNA from 77 patients, and compared with RT-PCR in terms of the diagnostic accuracy based on the results of follow-up survey. 26 patients of COVID-19 with negative RT-PCR reports were reported as positive by ddPCR. The sensitivity, specificity, PPV, NPV, negative likelihood ratio (NLR) and accuracy were improved from 40% (95% CI: 27–55%), 100% (95% CI: 54–100%), 100%, 16% (95% CI: 13–19%), 0.6 (95% CI: 0.48–0.75) and 47% (95% CI: 33–60%) for RT-PCR to 94% (95% CI: 83–99%), 100% (95% CI: 48–100%), 100%, 63% (95% CI: 36–83%), 0.06 (95% CI: 0.02–0.18), and 95% (95% CI: 84–99%) for ddPCR, respectively. Moreover, 6/14 (42.9%) convalescents were detected as positive by ddPCR at 5–12 days post discharge. Overall, ddPCR shows superiority for clinical diagnosis of SARS-CoV-2 to reduce the false negative reports, which could be a powerful complement to the RT-PCR.

Adaptation in structured populations and fuzzy boundaries between hard and soft sweeps.

Selective sweeps, the genetic footprint of positive selection, have been extensively studied in the past decades, with dozens of methods developed to identify swept regions. However, these methods suffer from both false positive and false negative reports, and the candidates identified with different methods are often inconsistent with each other. We propose that a biological cause of this problem can be population subdivision, and a technical cause can be incomplete, or inaccurate, modeling of the dynamic process associated with sweeps. Here we used simulations to show how these effects interact and potentially cause bias. In particular, we show that sweeps maybe misclassified as either hard or soft, when the true time stage of a sweep and that implied, or pre-supposed, by the model do not match. We call this “temporal misclassification”. Similarly, “spatial misclassification (softening)” can occur when hard sweeps, which are imported by migration into a new subpopulation, are falsely identified as soft. This can easily happen in case of local adaptation, i.e. when the sweeping allele is not under positive selection in the new subpopulation, and the underlying model assumes panmixis instead of substructure. The claim that most sweeps in the evolutionary history of humans were soft, may have to be reconsidered in the light of these findings.

Reanalysis of whole exome sequencing data in patients with epilepsy and intellectual disability/mental retardation

To evaluate the additional diagnostic yield of whole exome sequencing (WES) reanalysis in patients with epilepsy and intellectual disability/mental retardation, we reanalyzed raw WES data and clinical information for 76 patient trios whose initial reports returned negative results. Eight patients (10.5%, 8/76) had positive genetic diagnoses finally, including six novel mutations in five genes. The reasons for the previous false-negative reports were divided into four categories: specific gene–disease associations had not been established at the time of the initial report; the disease database of the genetic test center had not been updated in a timely manner; the patient's clinical phenotype had not been carefully or correctly collected, submitted and reviewed when applicating genetic test and analyzing the variants; and the first round of data analysis missed a synonymous variant that affected splicing. Therefore, physicians should not give up the discovery of disease-causing mutations before re-examining the WES data and clinical phenotype by themselves or by collaborating with bioinformatic experts in the genetic test centers, especially for patients with strongly suspected genetic disease whose initial WES result was “negative”. The suitable time points for reanalysis might be the 6–12 months after initial report.

Efficient and Scalable Runtime Monitoring for Cyber–Physical System

Our reliance on cyber–physical systems (CPSs) is increasingly widespread, but scalable methods for the analysis of such systems remain a significant challenge. Runtime verification of CPSs provides a reasonable middle ground between formal verification and simulation approaches, but it comes with its own challenges. A runtime verification system must run directly on the deployed application. In the CPS domain, it is therefore critical that a runtime verification system exhibits low overhead and good scalability so that the verification does not interfere with the analyzed CPS application. In this paper, we introduce Brace , a runtime verification system whose focus is on ensuring these performance qualities for applications in the CPS domain. Brace strives to bound the computation overhead for CPS runtime verification while preserving a high level of monitoring accuracy in terms of the number of false positive and false negative reports. Brace is particularly suitable to systems in which scheduling is distributed across networked CPS components. We evaluate Brace to determine how effectively and efficiently it can detect injected errors in two existing real-life CPS applications with distributed scheduling. Our results demonstrate that Brace efficiently detects those errors and a few true bugs and is able to bound both the memory and computation overhead even in systems with large numbers of observed events.

Dilute Russel Viper Venom Time analysis in a Haematology Laboratory: An audit.

To determine whether the current set of evaluation criteria used for dilute Russel Viper Venom Time (dRVVT) investigations in the routine laboratory meet expectation and identify possible shortcomings. All dRVVT assays requested from January 2015 to December 2015 were appraised in this cross-sectional study. The raw data panels were compared with the new reference interval, established in 2016, to determine the sequence of assays that should have been performed. The interpretive comments were audited, and false-negative reports identified. Interpretive comments according to three interpretation guidelines were compared. The reagent cost per assay was determined, and reagent cost wastage, due to redundant tests, was calculated. Only ~9% of dRVVT results authorized during 2015 had an interpretive comment included in the report. ~15% of these results were false-negative interpretations. There is a significant statistical difference in interpretive comments between the three interpretation methods. Redundant mixing tests resulted in R 7477.91 (~11%) reagent cost wastage in 2015. We managed to demonstrate very evident deficiencies in our own practice and managed to establish a standardized workflow that will potentially render our service more efficient and cost effective, aiding clinicians in making improved treatment decisions and diagnoses. Furthermore, it is essential that standard operating procedures be kept up to date and executed by all staff in the laboratory.

77P Is there an incremental benefit with 68 Ga DOTA PET/CT in staging of broncho-pulmonary carcinoid tumors?

Background: The staging of well differentiated bronchopulmonary neuroendocrine tumours (carcinoids) is complicated by the unpredictable incidence of nodal and distal metastases. PET CECT which has become the standard for staging of lung cancers has proven ineffective in the staging of carcinoid tumours. 68 Ga DOTA NOC PET/CT which depends on radio-tracer uptake in somatostatin receptors appears to be an attractive modality for the staging of these neuroendocrine tumours. Methods: We performed a retrospective analysis of patients who underwent 68 Ga DOTA NOC PET/CT followed by surgical resection from October 2014 to November 2017. Data was retrieved regarding demographics, standardized uptake value (SUV), surgery performed and final histopathology report including degree of differentiation, nodal positivity and Mib index. The study included only patients who underwent resection since the focus of the study on corelation with histopathological features. An attempt was made to corelate the SUV with diagnosis of typical vs atypical carcinoid, nodal metastases and Mib index. Results: During the study period 38 patients underwent surgical resection following DOTA PET. All details of imaging including SUV were available for 35 patients, while complete histopathological details were available for 37 patients. DOTA PET was not able to differentiate between typical and atypical carcinoids (32 vs 3) based on SUV. The mean SUV of typical carcinoids was 41.4(SD-41.2) whereas that of atypical carcinoids was 34.4(SD-39.4) and the difference was not statistically significant (p = 0.7). 6/37 cases had nodal metastases of which DOTA PET could corrrectly identify only 1. There were 2 false positive reports and 5 false negative reports, (sensitivity 16.6% and specificity 93.5%). The mean SUV of the false positive nodes (n = 2 cases) was 7 which calls into question the specificity of the tracer. No corelation between SUV and Mib index could be demonstrated, p = 0.37. Conclusions: In this study 68 Ga DOTA NOC PET CECT could not help in predicting the histopathological nature of carcinoid tumours, atypical vs typical, presence of nodal metastases or Mib index. This study is limited by the small numbers enrolled, a larger series may help us incoming to a more definitive conclusion. Legal entity responsible for the study: Tata Memorial Hospital Funding: Has not received any funding Disclosure: The author has declared no conflicts of interest.

Subspecialized radiology review at multidisciplinary pancreas conference: impact on patient management.

At our tertiary medical center, multidisciplinary subspecialists meet twice a week during a CME-accredited conference to discuss oncologic and non-oncologic patients with pancreatic diseases at which time a subspecialized abdominal staff radiologist reinterprets the patient's relevant imaging studies. This study assesses the changes in patient management due to imaging reinterpretation during multidisciplinary pancreas conference (MPC). In this retrospective, IRB-approved, HIPAA-compliant study, imaging studies of all patients discussed at MPC between July 1 and December 31, 2015 were assessed for technical adequacy, and original reports analyzed for congruency with reinterpretation. Management measures included change in diagnosis, clinical stage, treatment, or workup. Additional data were obtained on referring services affected and their resultant change in practice. Changes in surgical resectability, surgical approach, or delayed operative dates were noted for surgeons. Changes in chemotherapeutic or radiation oncology regimens as well as decisions for additional imaging, laboratory workup, or histologic evaluation were also recorded. A total of 252 patients were included (54.4% males, 45.6% females, mean age 63.71years). Relevant imaging consisted of 142 abdominal CT scans, 112 abdominal MRI scans, 1 abdominal ultrasound, and 1 nuclear medicine octreotide study of which 69.4% were performed in-house. Image quality was deemed appropriate in 95.2%. Cases presented included solid pancreatic malignancies (n = 140; 55.6%), cystic pancreatic lesions (n = 41; 16.3%), acute and chronic inflammatory conditions (n = 52; 20.6%), and miscellaneous entities (n = 10; 4.0%); 9 (3.6%) cases were normal. Image reinterpretation was congruent with original reports in 56.7%, with minor, moderate, and major discrepancies occurring in 9.5, 26.2%, and 7.5% of cases, respectively. Incongruent reinterpretation was predominantly due to perceptional errors (false-negative reports due to missed findings) and interpretative errors (false-positive results due to over-reporting or misclassification of diagnoses). Services most commonly affected included surgical oncology, radiology, and gastroenterology at 16.7%, 13.1%, and 12.7% of cases, respectively. Management changes included a change in diagnosis in 8.7%, change in clinical stage in 8.7%, change in treatment in 17.9%, and further workup needed in 19.0% of patients, respectively. No change in management occurred in the remaining 61.5% of cases. Subspecialized abdominal radiologist reinterpretation in the context of more comprehensive patient information heavily impacts the multidisciplinary management of patients with pancreatic disorders. Further efforts are needed to solidify the abdominal radiologist's role in the multidisciplinary clinical setting.

English

BACKGROUND Fine needle aspiration cytology (FNAC) is a well-accepted and safe diagnostic procedure for the superficial lesions of the body; however, it can also be used for intrathoracic lesions with or without radiological guidance. The objective is to study the utility of unguided transthoracic FNAC as a diagnostic aid in intrathoracic lesions. MATERIALS AND METHODS This descriptive study of one hundred and fifteen cases of intrathoracic lesions presenting as pulmonary nodules was done by unguided transthoracic fine needle aspiration cytology (TFNAC) to assess the diagnostic accuracy. RESULTS The yield was diagnostic in 76 cases. Among the 76 cases, 64 cases were malignant lesions & 12 were non-neoplastic. There were no false positives; however, 5 cases showed false negative reports. The sensitivity, specificity and positive predictive value were 90.1%, 100% and 100% respectively. Minimal complications were encountered like pain at the punctured site, blood-tinged sputum and pneumothorax in two cases. CONCLUSION Unguided TFNAC is a simple, dependable and economical procedure for the diagnosis of peripheral lung lesions.

Health disparities across education: The role of differential reporting error.

One of the most robust findings in health economics is that higher educated individuals tend to be in better health. This paper tests whether health disparities across education are to some extent due to differences in reporting error across education. We test this hypothesis using data from the pooled National Health and Nutrition Examination Survey (NHANES) for 1999-2012, which include both self-reports and objective verification for an extensive set of health behaviors and conditions, including smoking, obesity, high blood pressure, high cholesterol, and diabetes. We find that college graduates are more likely to give false negative reports of obesity and high total cholesterol; one possible explanation for this is social desirability bias. However, college graduates are also significantly less likely to give false positive reports of smoking, obesity, and high cholesterol. Because there are far more truly negative people (who are less likely to give a false positive report) than more truly positive people (who are more likely to give a false negative report), we find that college graduates report their health significantly more accurately overall.

Onychomycosis InfectionsDo Polymerase Chain Reaction and Culture Reports Agree?

Mycological culture is the traditional method for identifying infecting agents of onychomycosis despite high false-negative results, slower processing, and complications surrounding nondermatophyte mold (NDM) infections. Molecular polymerase chain reaction (PCR) methods are faster and suited for ascertaining NDM infections. To measure agreement between culture and PCR methods for identification of infecting species of suspected onychomycosis, single toenail samples from 167 patients and repeated serial samples from 43 patients with suspected onychomycosis were processed by culture and PCR for identification of 16 dermatophytes and five NDMs. Agreement between methods was quantified using the kappa statistic (κ). The methods exhibited fair agreement for the identification of all infecting organisms (single samples: κ = 0.32; repeated samples: κ = 0.38). For dermatophytes, agreement was moderate (single samples: κ = 0.44; repeated samples: κ = 0.42). For NDMs, agreement was poor with single samples (κ = 0.16) but fair with repeated samples (κ = 0.25). Excluding false-negative reports from analyses improved agreement between methods in all cases except the identification of NDMs from single samples. Culture was three or four times more likely to report a false-negative result compared with PCR. The increased agreement between methods observed by excluding false-negative reports statistically clarifies and highlights the major discord caused by false-negative cultures. The increased agreement of NDM identification from poor to fair with repeated sampling along with their poor agreement in the single samples, with and without false-negatives, affirms the complications of NDM identification and supports the recommendation that serial samples help confirm the diagnosis of NDM infections.

Thin isotropic FLAIR MR images at 1.5T increase the yield of focal cortical dysplasia transmantle sign detection in frontal lobe epilepsy

ObjectiveThe transmantle sign is a distinctive imaging marker of focal cortical dysplasia (FCD) type II in frontal lobe epilepsy (FLE), which is revealed predominantly by fluid-attenuation inversion recovery (FLAIR) sequences. Although the transmantle sign detection yield is high by routine imaging protocols for epilepsy at 3T, most centers around the world have access to 1.5T MR technology and FLE patients often receive negative imaging reports. This study investigates the optimization of transmantle detection yield at 1.5T by introducing a 3D thin-slice isotropic FLAIR sequence in the epilepsy imaging protocol. MethodsTwenty FLE patients underwent diagnostic imaging for epilepsy with typical 2D thick-slice (3.0mm) coronal FLAIR sequences and a 3D thin-slice (1.0mm) isotropic FLAIR sequences at 1.5T, and transmantle sign detection yields and thickness measurements were derived. ResultsThe 2D thick-slice FLAIR detected a transmantle sign in seven (35.0%) patients. The 3D isotropic thin-slice FLAIR detected a transmantle sign in eleven (55.0%) patients, thereby increasing the transmantle sign detection yield by 57.4%. The mean transmantle sign thickness by thick images was 12.3mm, by thin images was 8.9mm, and in the patients undetected by thick FLAIR was 3.5mm. SignificanceThis study showed that the extratemporal transmantle sign in FLE patients can be thin enough to be missed by thick-slice FLAIR sequences at 1.5T. By introducing 3D thin-slice isotropic FLAIR, false-negative reports can be reduced without reference for higher MR field structural scanning or other modalities, and more FLE patients can benefit from epilepsy surgery candidacy.

Role of morphometry in the cytological differentiation of benign and malignant thyroid lesions.

Context:Thyroid nodules represent a common problem, with an estimated prevalence of 4–7%. Although fine needle aspiration cytology (FNAC) has been accepted as a first line diagnostic test, the rate of false negative reports of malignancy is still high. Nuclear morphometry is the measurement of nuclear parameters by image analysis. Image analysis can merge the advantages of morphologic interpretation with those of quantitative data.Aims:To evaluate the nuclear morphometric parameters in fine needle aspirates of thyroid lesions and to study its role in differentiating benign from malignant thyroid lesions.Material and Methods:The study included 19 benign and 16 malignant thyroid lesions. Image analysis was performed on Giemsa-stained FNAC slides by Nikon NIS-Elements Advanced Research software (Version 4.00). Nuclear morphometric parameters analyzed included nuclear size, shape, texture, and density parameters.Statistical Analysis:Normally distributed continuous variables were compared using the unpaired t-test for two groups and analysis of variance was used for three or more groups. Tukey or Tamhane's T2 multiple comparison test was used to assess the differences between the individual groups. Categorical variables were analyzed using the chi square test.Results and Conclusion:Five out of the six nuclear size parameters as well as all the texture and density parameters studied were significant in distinguishing between benign and malignant thyroid lesions (P < 0.05). Cut-off values were derived to differentiate between benign and malignant cases.