scholarly journals Analysis of Preoperative Detection for Apex Prostate Cancer by Transrectal Biopsy

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Tomokazu Sazuka ◽  
Takashi Imamoto ◽  
Takeshi Namekawa ◽  
Takanobu Utsumi ◽  
Mitsuru Yanagisawa ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Needle Biopsy ◽  
False Negative ◽  
False Negative Rate ◽  
Japanese Patients ◽  
False Negatives ◽  
Transrectal Biopsy ◽  
High False Negative Rate ◽  
Accurate Imaging ◽  
Preoperative Factors

Background. The aim of this study was to determine concordance rates for prostatectomy specimens and transrectal needle biopsy samples in various areas of the prostate in order to assess diagnostic accuracy of the transrectal biopsy approach, especially for presurgical detection of cancer in the prostatic apex.Materials and Methods. From 2006 to 2011, 158 patients whose radical prostatectomy specimens had been evaluated were retrospectively enrolled in this study. Concordance rates for histopathology results of prostatectomy specimens and needle biopsy samples were evaluated in 8 prostatic sections (apex, middle, base, and transitional zones bilaterally) from 73 patients diagnosed at this institution, besides factors for detecting apex cancer in total 118 true positive and false negative apex cancers.Results. Prostate cancer was found most frequently (85%) in the apex of all patients. Of 584 histopathology sections, 153 (49%) from all areas were false negatives, as were 45% of apex biopsy samples. No readily available preoperative factors for detecting apex cancer were identified.Conclusions. In Japanese patients, the most frequent location of prostate cancer is in the apex. There is a high false negative rate for transrectal biopsy samples. To improve the detection rate, transperitoneal biopsy or more accurate imaging technology is needed.

Correct Classification, False Positives, and False Negatives in Predicting Completion of the Ph.d. from GRE Scores

1996 ◽  
Vol 79 (3) ◽  
pp. 939-945 ◽  
Author(s):  
Cooper B. Holmes ◽  
Megan J. Beishline
Keyword(s):  
Success Rate ◽  
False Negative ◽  
False Negative Rate ◽  
Doctoral Program ◽  
False Positives ◽  
Correct Classification ◽  
False Negatives ◽  
Program Success ◽  
High False Negative Rate ◽  
Psychology Doctoral

Combined Verbal and Quantitative GRE scores were obtained from the records of 24 former students of a master's degree program (from a total of 128 students) who had successfully completed a doctorate in psychology or who had withdrawn from a psychology doctoral program. Success rate by classification with the GRE was calculated using both a cut-off of 1000 and a cut-off of 1100. The results indicated a high false negative rate, that is, students whose GRE scores would not predict success but who obtained a Ph.D.

Is histoscanning a valid tool to detect prostate cancer in repeat biopsy?

2012 ◽  
Vol 30 (5_suppl) ◽  
pp. 57-57
Author(s):  
Robin Epplen ◽  
Julius van Essen ◽  
David J. K. P. Pfister ◽  
Daniel Porres ◽  
Axel Heidenreich
Keyword(s):  
Prostate Cancer ◽  
Statistical Significance ◽  
False Positive Rate ◽  
False Negative ◽  
False Negative Rate ◽  
Repeat Biopsy ◽  
Grid Pattern ◽  
Transrectal Biopsy ◽  
Positive Rate ◽  
Positive Core

57 Background: Histoscanning is a novel ultrasound-based software programme, which uses back-scattered ultrasound, to detect and visualize prostate carcinoma. It is not clear to date which additive information histoscanning will deliver terms of additive information to ultrasound guided transrectal biopsy as research is scarce.Therefore we aimed to analyze our data on repeat biopsy with histoscanning prior to intervention. Methods: From Sept. 2009 till present, 61 patients, mean age 62 yrs, that were scheduled for repeat biopsy received Histoscanning prior to intervention. Acquired data were retrospectively processed with Histoscanning software version 2.2 and prostate was divided into a 6 grid pattern. Lesions ≥0,5ml were considered positive. Biopsies were taken according to Vienna normogram and processed by an experienced uropathologist. Results: Mean number of biopsies prior to repeat was 2. Mean PSA at repeat biopsy was 7,135 ng/ml, mean prostate volume accounted for 45.5 ml. A total of 15/61 men were diagnosed with cancer (24,59%), Gleason Score (Gl.) of 6 n=10, n=2 Gl. 3+4=7, n=2 Gl. 4+4; n=2 Gl. 4+5=9 respectively. A total of 43/834=5.15% positive cores were obtained, averaging 0.7 per person. Mean Volume of Histoscanning lesions per scan: 1,48 ml; no statistical significance can be detected regarding the volume per sextant and a positive core. False positive rate was 90/366=24,6%; false negative rate was 19/366=5,2%. Overall sensitivity was 29,69%, specifity accounted for 73.3%. PPV was calculated at 8.16% and NPV at 92,88%. PSA had no influence on detection rate. Conclusions: In this highly seleted patient cohort Histoscanning had no beneficial nor additive information on detecting prostate cancer. Further research should has to be done regarding Histoscanning lesions with different histopathological features such as prostatitis and fibrosis.

Clinically Meaningful Change

Methodology ◽  
2019 ◽  
Vol 15 (3) ◽  
pp. 97-105
Author(s):  
Rodrigo Ferrer ◽  
Antonio Pardo
Keyword(s):  
Effect Size ◽  
False Negative ◽  
False Negative Rate ◽  
Point Of View ◽  
Skewed Distribution ◽  
Effect Sizes ◽  
False Negatives ◽  
Large Size ◽  
Before And After ◽  
Post Test

Abstract. In a recent paper, Ferrer and Pardo (2014) tested several distribution-based methods designed to assess when test scores obtained before and after an intervention reflect a statistically reliable change. However, we still do not know how these methods perform from the point of view of false negatives. For this purpose, we have simulated change scenarios (different effect sizes in a pre-post-test design) with distributions of different shapes and with different sample sizes. For each simulated scenario, we generated 1,000 samples. In each sample, we recorded the false-negative rate of the five distribution-based methods with the best performance from the point of view of the false positives. Our results have revealed unacceptable rates of false negatives even with effects of very large size, starting from 31.8% in an optimistic scenario (effect size of 2.0 and a normal distribution) to 99.9% in the worst scenario (effect size of 0.2 and a highly skewed distribution). Therefore, our results suggest that the widely used distribution-based methods must be applied with caution in a clinical context, because they need huge effect sizes to detect a true change. However, we made some considerations regarding the effect size and the cut-off points commonly used which allow us to be more precise in our estimates.

scholarly journals External validation for sensitivity of the Ottawa subarachnoid hemorrhage rule in a Japanese tertiary teaching hospital

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomoharu Suzuki ◽  
David Itokazu ◽  
Yasuharu Tokuda
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Teaching Hospital ◽  
Tertiary Care ◽  
External Validation ◽  
False Negative ◽  
False Negative Rate ◽  
Prediction Rule ◽  
Japanese Patients ◽  
Inclusion Criteria ◽  
Tertiary Teaching

AbstractThe Ottawa subarachnoid hemorrhage (OSAH) rule is a validated clinical prediction rule for ruling out subarachnoid hemorrhage (SAH). Another SAH rule (Ottawa-like rule) was developed in Japan but was not well validated. We aimed to validate both rules by examining the sensitivity for ruling out SAH in Japanese patients diagnosed with SAH. We conducted a retrospective cohort study by reviewing the medical records of consecutive adult patients hospitalized with SAH at a tertiary-care teaching hospital in Japan who visited our emergency department between July 2009 and June 2019. Sensitivity and its 95% confidence interval (CI) were estimated for each rule for the diagnosis of SAH. In a total of 280 patients with SAH, 56 (20.0%) patients met the inclusion criteria and were analyzed for the OSAH rule, and a sensitivity of the OSAH rule was 56/56 (100%; 95% CI 93.6–100%). While, 126 (45%) patients met the inclusion criteria of the Ottawa-like rule, and the rule showed a sensitivity of 125/126 (99.2%; 95%CI 95.7–100%). The OSAH rule showed 100% sensitivity among our Japanese patients diagnosed with SAH. The implementation of the Ottawa-like rule should be cautious because the false-negative rate is up to 4%.

scholarly journals High mortality with High false negative rate: COVID-19 infection in patients with hematologic malignancies

2021 ◽  
Vol 106 ◽  
pp. 106582
Author(s):  
Alex Niu ◽  
Bo Ning ◽  
Francisco Socola ◽  
Hana Safah ◽  
Tim Reynolds ◽  
...  
Keyword(s):  
High Mortality ◽  
False Negative ◽  
False Negative Rate ◽  
Hematologic Malignancies ◽  
Negative Rate ◽  
High False Negative Rate

scholarly journals Application of Immunosignatures for Diagnosis of Valley Fever

2014 ◽  
Vol 21 (8) ◽  
pp. 1169-1177 ◽  
Author(s):  
Krupa Arun Navalkar ◽  
Stephen Albert Johnston ◽  
Neal Woodbury ◽  
John N. Galgiani ◽  
D. Mitchell Magee ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Random Sequence ◽  
False Negative ◽  
False Negative Rate ◽  
Peptide Array ◽  
Igg Antibodies ◽  
False Negatives ◽  
Peptide Microarray ◽  
Valley Fever ◽  
Antibody Levels

ABSTRACTValley fever (VF) is difficult to diagnose, partly because the symptoms of VF are confounded with those of other community-acquired pneumonias. Confirmatory diagnostics detect IgM and IgG antibodies against coccidioidal antigens via immunodiffusion (ID). The false-negative rate can be as high as 50% to 70%, with 5% of symptomatic patients never showing detectable antibody levels. In this study, we tested whether the immunosignature diagnostic can resolve VF false negatives. An immunosignature is the pattern of antibody binding to random-sequence peptides on a peptide microarray. A 10,000-peptide microarray was first used to determine whether valley fever patients can be distinguished from 3 other cohorts with similar infections. After determining the VF-specific peptides, a small 96-peptide diagnostic array was created and tested. The performances of the 10,000-peptide array and the 96-peptide diagnostic array were compared to that of the ID diagnostic standard. The 10,000-peptide microarray classified the VF samples from the other 3 infections with 98% accuracy. It also classified VF false-negative patients with 100% sensitivity in a blinded test set versus 28% sensitivity for ID. The immunosignature microarray has potential for simultaneously distinguishing valley fever patients from those with other fungal or bacterial infections. The same 10,000-peptide array can diagnose VF false-negative patients with 100% sensitivity. The smaller 96-peptide diagnostic array was less specific for diagnosing false negatives. We conclude that the performance of the immunosignature diagnostic exceeds that of the existing standard, and the immunosignature can distinguish related infections and might be used in lieu of existing diagnostics.

scholarly journals False Negative Mitigation in Group Testing for COVID-19 Screening

2021 ◽  
Vol 8 ◽  
Author(s):  
Amir Reza Alizad Rahvar ◽  
Safar Vafadar ◽  
Mehdi Totonchi ◽  
Mehdi Sadeghi
Keyword(s):  
Viral Load ◽  
False Negative ◽  
Group Testing ◽  
False Negative Rate ◽  
Screening Strategy ◽  
Web Interface ◽  
Rt Pcr ◽  
Promising Candidate ◽  
Testing Method ◽  
High False Negative Rate

After lifting the COVID-19 lockdown restrictions and opening businesses, screening is essential to prevent the spread of the virus. Group testing could be a promising candidate for screening to save time and resources. However, due to the high false-negative rate (FNR) of the RT-PCR diagnostic test, we should be cautious about using group testing because a group's false-negative result identifies all the individuals in a group as uninfected. Repeating the test is the best solution to reduce the FNR, and repeats should be integrated with the group-testing method to increase the sensitivity of the test. The simplest way is to replicate the test twice for each group (the 2Rgt method). In this paper, we present a new method for group testing (the groupMix method), which integrates two repeats in the test. Then we introduce the 2-stage sequential version of both the groupMix and the 2Rgt methods. We compare these methods analytically regarding the sensitivity and the average number of tests. The tradeoff between the sensitivity and the average number of tests should be considered when choosing the best method for the screening strategy. We applied the groupMix method to screening 263 people and identified 2 infected individuals by performing 98 tests. This method achieved a 63% saving in the number of tests compared to individual testing. Our experimental results show that in COVID-19 screening, the viral load can be low, and the group size should not be more than 6; otherwise, the FNR increases significantly. A web interface of the groupMix method is publicly available for laboratories to implement this method.

Pathologic Assessment of Computerized Tomography Accuracy for the Evaluation of the Laryngeal Cartilaginous Frame Work in Laryngopharyngeal Carcinomas

1989 ◽  
Vol 75 (2) ◽  
pp. 156-162 ◽  
Author(s):  
Sandro Sulfaro ◽  
Francesco Querin ◽  
Luigi Barzan ◽  
Mario Lutman ◽  
Roberto Comoretto ◽  
...  
Keyword(s):  
Computerized Tomography ◽  
False Positive ◽  
False Positive Rate ◽  
False Negative ◽  
False Negative Rate ◽  
Cartilage Destruction ◽  
High False Negative Rate ◽  
Positive Rate ◽  
Pathologic Assessment ◽  
Low Sensitivity

Sixty-six whole-organ sectioned laryngopharyngectomy specimens removed for cancer during a seven-year period were uniformly examined to determine the accuracy of preoperative high resolution computerized tomography (CT) for detection of cartilaginous involvement. Our results indicate that CT has a high overall specificity (88.2%) but a low sensitivity (47.1 %); we observed a high false-negative rate (26.5%) and a fairly low false-positive rate (5.9%). Massive cartilage destruction was easily assessed by CT, whereas both small macroscopic and microscopic neoplastic foci of cartilaginous invasion were missed on CT scans. Moreover, false-positive cases were mainly due to proximity of the tumor to the cartilage. Clinical implications of these results are discussed.

Measurement differences between three versus five photocells during collection of ground reaction forces in dogs

2007 ◽  
Vol 02 (02) ◽  
pp. 98-101 ◽  
Author(s):  
J. P. Punke ◽  
A. L. Speas ◽  
L. R. Reynolds ◽  
C. M. Andrews ◽  
S. C. Budsberg
Keyword(s):  
Ground Reaction Force ◽  
Reaction Force ◽  
False Negative ◽  
False Negative Rate ◽  
Second Phase ◽  
False Negatives ◽  
Two Systems ◽  
Reaction Forces ◽  
Force Data ◽  
Gathering Data

SummaryThe differences between velocities and accelerations obtained from three and five photocells were examined when obtaining ground reaction force (GRF) data in dogs. Ground reaction force data was collected 259 times from 16 different dogs in two experimental phases. The first phase compared velocities and accelerations reported by the two systems based on trials accepted by the three photocell system. The second phase accepted trials based on data from five photocells. Three photocell data were calculated mathematically in the second phase in order to compare the values of both systems. The velocity and acceleration values obtained from each system were significantly different (at the hundredth of a meter per second). Differences in measured values did not result in acceptance of data by the three photocell system that would not have been acceptable with the five photocell system (false positives), but did result in rejection of acceptable data by the three photocell system (11% false negative rate). Given the small differences between the two systems, GRF data collected should not be significantly different, though the three photocell system is less efficient in gathering data due to the number of trials rejected as false negatives.

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