CONTEXT: (18)FDG is used widely to enhance PET and PET-CT images. However, this radiotracer tends to be taken up by brown fat, which can lead to false-positive diagnoses. Purpose To determine which patients, areas of the body and circumstances are more likely to be associated with false-positive diagnoses due to (18)FDG uptake in brown fat. METHOD: A review of the literature was conducted on factors that contribute to false-positive diagnoses caused by (18)FDG uptake in brown fat. RESULTS: Brown fat commonly is found in women and children and can be located in the supraclavicular, mediastinal, paravertebral and perirenal areas of the body. Research has shown that these areas can be sources of a false-positive diagnosis because of (18)FDG uptake. Studies also have indicated that cold climate affects the uptake of (18)FDG, contributing to false-positive results on PET-CT examinations. CONCLUSIONS: This literature review should stimulate continued research into and awareness of the potential for false-positive PET findings in women and children during the winter months and in cold climates. This information is especially applicable to young female patients undergoing PET or PET-CT.
In the last several years, West Nile virus (WNV) was proven to be present especially in the neighboring countries of Austria, such as Italy, Hungary, and the Czech Republic, as well as in eastern parts of Austria, where it was detected in migratory and domestic birds. In summer 2010, infections with WNV were reported from Romania and northern Greece with about 150 diseased and increasingly fatal cases. We tested the sera of 1,607 blood donors from North Tyrol (Austria) and South Tyrol (Italy) for antibodies against WNV by using IgG enzyme-linked immunosorbent assay (ELISA). Initial results of the ELISA tests showed seroprevalence rates of 46.2% in North Tyrol and 0.5% in South Tyrol, which turned out to be false-positive cross-reactions with antibodies against tick-borne encephalitis virus (TBEV) by adjacent neutralization assays. These results indicate that seropositivity against WNV requires confirmation by neutralization assays, as cross-reactivity with TBEV is frequent and because, currently, WNV is not endemic in the study area.
Follicular cervicitis is usually easily identifiable on Papanicolaou (Pap) tests; however, historically, follicular cervicitis is reported to lead to false-positive diagnoses of epithelial cell abnormalities.
To assess participant responses in the College of American Pathologists (CAP) Pap educational program (CAP-PAP) to determine the accuracy and false-positive rate of follicular cervicitis cases. Design.-We performed a retrospective review of 4914 participant responses for gynecologic cytology challenges with the reference diagnosis of follicular cervicitis during 11 years (2000-2010) from CAP-PAP. Reference diagnosis category, false-positive rates by participant type (laboratory, cytotechnologist, pathologist), and preparation type (conventional smears, ThinPrep) were analyzed.
Of the total 4914 general category responses, 4368 (88.9%) were benign while 546 (11.1%) responses were epithelial cell abnormalities (false positives). Of benign responses, only 2026 (46.4%) were an exact match to follicular cervicitis. Adenocarcinoma and high-grade squamous intraepithelial lesion were the most common diagnoses chosen as a false-positive interpretation (42.3% and 20.1%, respectively). Participant type was significantly associated with false-positive interpretations (laboratory: 19.2%; cytotechnologist: 11.1%; pathologist: 7.9%; P
In 63 teenagers the proximal surfaces of premolars to be extracted for orthodontic reasons and the adjacent surfaces of neighboring teeth, 598 surfaces in all, were examined radiographically and by probing. Direct inspection after extraction revealed that 51% of the surfaces had incipient carious lesions and 5% lesions with cavities. Of the surfaces with cavities 82.1% were correctly diagnosed radiographically if any radiolucency, regardless of its extent, was used as a diagnostic criterion. However, this yielded a false positive rate of 19.6%. If only radiolucencies extending at least into the inner third of the enamel were called positive the true positive rate was 36.7% and the associated false positive rate 1.6%. At a 5% cavity frequency the predictive positive values were 17% and 53%, respectively. Probing yielded a true positive rate of about 29% and a false positive rate of 1.1% with a predictive positive value of 50-57%. All radiolucencies extending into the dentin were associated with cavities. When the most liberal radiographic criterion was used 37.5% of all carious lesions, whether associated with a cavity or not, were detected and 3.8% of sound surfaces were falsely called carious. The corresponding predictive positive value at the actual rate of incipient lesions and lesions with cavities was 92.6%.
The first link in the 'chain of survival' is the activation of Emergency Medical Services (EMS). In the major part of Denmark, police officers operate the alarm 1-1-2 centre, including calls for EMS. Our aim was to study the police 1-1-2 operators' accuracy in identifying calls concerning patients with loss of consciousness as a key symptom of life-threatening conditions. 'Unconsciousness' was defined as patients with a Glasgow Coma Scale (GCS) score of or = 9, 972 of whom were reported 'awake', giving a specificity of 72%. The positive predictive value (percentage of patients found with a GCS score of
During a 1-year period 4785 intraoperative consultations were performed. The pathology reports were retrospectively reviewed to determine the accuracy of frozen section diagnosis in various tissue types. Skin for evaluation of section margins and axillary sentinel lymph nodes for evaluation of metastatic disease were most frequently sent for frozen section diagnosis. The number of discordant cases were 182, 178 were false negative and four were false positive. When frozen section diagnoses were compared with permanent section diagnoses, the overall diagnostic concordance was 95.1%. The number of deferred specimens was 57. The accuracy of frozen section diagnosis varied between tissue types, and axillary sentinel lymph nodes accounted for the greatest number of discordances. In conclusion, the frozen section diagnosis is a reliable method with varying concordance and deferral rates between tissue types. We suggest regular monitoring of the performance in frozen section diagnosis.
There is a wide variation in reported accuracy ofnoninvasive stress myocardial imaging as a screening tool for coronary artery disease (CAD). This study was undertaken to determine its current accuracy in a wide spectrum of patients with chest pain syndromes using invasive coronary angiography as the gold standard.
The patient population consisted of consecutive patients undergoing coronary angiography in whom noninvasive stress imaging, either nuclear or echocardiographic, was performed within 6 months prior to the angiogram. The specificity, sensitivity, positive and negative predictive values, and diagnostic accuracy for detecting > or =1 lesions with > or =50% diameter coronary stenosis were determined for each modality.
Of the 227 eligible patients, 141 were men and 86 were women; 70% had significant CAD. The diagnostic accuracy overall was 71% and was no different for nuclear or echocardiographic testing. The positive predictive value (86% vs. 52%; P = 0.002) and diagnostic accuracy (83% vs. 51%; P = 0.002) were better in men than in women.
In this study, noninvasive stress imaging lacked the accuracy of a good screening test for significant CAD. This finding was particularly true for women, for whom it was not much better than a coin toss.
To evaluate the possibility of applying the Third Molar Eruption Predictor to all panoramic radiographs.
Panoramic radiographs were retrospectively analyzed from a 4-year follow-up study of third molars carried out at the University of Copenhagen, Denmark. The radiographs, taken at a mean age of 20.6 years, included 45 unerupted or partially erupted mandibular third molars in 28 subjects. Because the device was calibrated both with simple proportions and by use of the methods of Bayes' Decision Theory, the separation point of the device was therefore adjusted at 12 mm from the distal surface of the second molar.
The predictions of future eruption or impaction made with the calibrated device and the actual clinical outcome 4 years later were in conformity for 80% of the mandibular third molars.
The Third Molar Eruption Predictor may be applied to all panoramic radiographs, but it seems to require calibration before use.
Psychological resistance may be of considerable importance in the posttraumatic stress disorder (PTSD) population, considering that researchers in the field of traumatic stress are frequently unsuccessful in achieving high response rates, that many subjects suffering from PTSD never seek help, and that dropouts from therapy are frequent. This article presents data on the main complaints reported in the acute aftermath of an industrial disaster by 246 employees who had been exposed to the disaster. The dominant concerns were symptomatic complaints related to posttraumatic stress reactions rather than external problems. Sleep disturbance, anxiety/fear responses, and physical symptoms were reported by individuals with complaints in the acute phase as most problematic, while irritability and depressive symptoms appeared very infrequently among the reported main complaints. A high specificity and sensitivity were achieved in predicting later PTSD (as defined by DSM-III criteria) by applying early response variables: thus, there were few false-positives and false-negatives. There was a considerable overlap between the PTSD predictors and the main symptom complaints. From a prevention point of view, this should be advantageous, since it would bring the right people to seek help. However, in a significant proportion of the acutely distressed, the reluctance to seek help was motivated by the very symptoms that predicted PTSD. Even a relatively high rate of subjects agreeing to be screened (82.8%) would have lost 42% of those who qualified for a diagnosis of PTSD, and more than half of the subjects with severe outcomes would not have been included. For primary and secondary prevention, the findings suggest that early screening and outreach should be very active.
To investigate the adverse effects associated with a false positive 50 g glucose challenge test for gestational diabetes mellitus (GDM).
Consecutive women attending a prenatal registration clinic at a large community hospital in suburban Toronto, Canada.
Prospective cohort study of women between 12 and 24 weeks' gestation with no previous history of diabetes mellitus or GDM. Main outcome measures included anxiety (Spielberger's State-Trait Anxiety Inventory), depression (Centers for Epidemiologic Studies Depression Scale), perceived maternal health, and concern about health of the newborn.
Among 2564 eligible subjects, there were 897 subjects with complete data at enrollment and at 32 weeks' gestation, including 88 who had false positive glucose challenge test results. At 32 weeks, only 20% (95% confidence limits 11%, 28%) of women with false positive glucose challenge test results rated their health as excellent, compared with 38% (35%, 42%) of those having negative results and those not tested (P = 0.001). These results were sustained at 36 weeks. There was no association between glucose challenge test result and the change in anxiety (P = 0.57), depression (P = 0.09) or concern about health of the newborn (P = 0.91) between baseline and 32 weeks' gestation, nor were these associations found at 36 weeks.
False positive glucose challenge test results are about six times more likely than true positive results in the general population. Pregnant women with false positive GDM screening results experience a significant decline in their perception of their own health. These adverse effects should be taken into account when deciding about a policy of screening all pregnant women for gestational diabetes.