Contrast-enhanced voiding urosonography phantom study: intravenous iodinated and gadolinium-based contrast agents may cause false-negative results in assessment of vesicoureteral reflux in children

2015 ◽  
Vol 45 (6) ◽  
pp. 862-871 ◽  
Author(s):  
Simon Veldhoen ◽  
Alexander Sauer ◽  
Tobias Gassenmaier ◽  
Bernhard Petritsch ◽  
Stefan Herz ◽  
...  
Keyword(s):  
Contrast Agents ◽  
Vesicoureteral Reflux ◽  
False Negative ◽  
Phantom Study ◽  
Voiding Urosonography ◽  
Negative Results ◽  
False Negative Results ◽  
Contrast Enhanced

scholarly journals An Experimental Approach to Risk of Organ Rejection: Demonstration of False Immunosuppressant Results Due to Radiopaque Agents

2019 ◽  
Author(s):  
Ataman Gönel ◽  
Ismail Koyuncu
Keyword(s):  
Cyclosporine A ◽  
Experimental Approach ◽  
False Negative ◽  
Therapeutic Index ◽  
Blood Levels ◽  
Organ Rejection ◽  
Negative Results ◽  
False Negative Results ◽  
Contrast Enhanced ◽  
Target Values

Background: Immunosuppressant blood levels should be measured at regular periods in order to keep them within the therapeutic index. Although LC-MS/MS is preferred as a reliable method, some molecules like radiopaque agents in blood matrix may lead to false results. The aim of this study is to investigate the effect of seven different radiopaque agents on immunosuppressant drugs. Methods: Seven different radiopaque agents were added into control materials containing tacrolimus, everolimus, sirolimus and cyclosporine A drugs. Measurements were performed by LC-MS/MS instrument. The amount of deviations from target values were calculated. Results: Immunosuppressant blood levels significantly changed after the administration of radiopaque agents. Seven different radiopaque products led to false negative results in tacrolimus and cyclosporine A levels at a rate of 19.77% to 44.45%. The smallest deviations were seen in everolimus levels with administration of RM6 (gadodiamide) and in sirolimus levels with RM1 (gadobutrol) at rates of 4.04% and 2.11%, respectively. The highest deviations were observed with RM3 (iohexol) administration in everolimus and sirolimus levels at rates of 153.72% and 171.41%, respectively. Conclusions: False immunosuppressant results associated with radiopaque agents may result in organ rejection. Preferring radiopaque agents that cause the least interference risk is important to reduce the organ rejection risk. However, the least risky method is to obtain samples for drug levels before contrast-enhanced imaging.

False Immunosuppressant Measurement by LC-MS/MS Method Due to Radiopaque Agents

2019 ◽  
Vol 22 (2) ◽  
pp. 129-134
Author(s):  
Ataman Gönel ◽  
Ismail Koyuncu
Keyword(s):  
Cyclosporine A ◽  
False Positive ◽  
False Negative ◽  
Gadopentetate Dimeglumine ◽  
Negative Results ◽  
False Negative Results ◽  
Contrast Enhanced ◽  
Deviation Rate ◽  
Instrument Bias ◽  
Enhanced Imaging

Background: Although liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) is preferred as a reliable method, some molecules in the blood matrix may lead to false positive or false negative results. False positive or negative results show the direction of the deviation rate from the target value. Aim: The aim of this study was to investigate the effect of seven different radiopaque agents on four immunosuppressant drugs. Methods: Every agent coded with RM1 to RM7 was added to control materials containing tacrolimus, everolimus, sirolimus, and cyclosporine A drugs. Measurements were performed using an LC-MS/MS instrument. Bias values were calculated to detect the deviation rates. Results: All RMs led to false negative results in the tacrolimus and cyclosporine A levels at a rate of -19.77% (95% CI, -27.16 to 12.52) to -44.45% (95% CI, -49.20 to -39.69). The smallest deviations were seen in the everolimus levels with the administration of RM6 (gadodiamide) and in the sirolimus levels with RM1 (gadobutrol) at the rates of 4.04% (95% CI, -11.36 to -3.17) and 2.11% (95% CI, -7.18 to 7.11), respectively. The most affected drug by RM4 (gadopentetate dimeglumine salt) was sirolimus at the rate of 114.01% (95% CI, 97.31 - 130.76). RM5 (gadodiamide) interfered cyclosporine A at the most. The highest deviations were observed with the administration of RM3 (iohexol) in the everolimus and sirolimus levels at the rates of 153.72% (95% CI, 142.44 to 164.78) and 171.41% (95% CI, 157.91 to 184.97), respectively. Conclusion: Radiopaque agents interfered the measurement of immunosuppressant drugs. Especially, everolimus and sirolimus levels were affected due to using iohexol. The choice of gadodiamide or ioversol is important to reduce the risk of interference for everolimus measurement. The blood samples should be obtained for measurement of drug levels before contrast-enhanced imaging.

scholarly journals Spinal arteriovenous shunts: accuracy of shunt detection, localization, and subtype discrimination using spinal magnetic resonance angiography and manual contrast injection using a syringe

2016 ◽  
Vol 24 (4) ◽  
pp. 664-670 ◽  
Author(s):  
Kittisak Unsrisong ◽  
Siriporn Taphey ◽  
Kanokporn Oranratanachai
Keyword(s):  
False Negative ◽  
Injection Technique ◽  
Contrast Injection ◽  
Accuracy Rate ◽  
Negative Results ◽  
False Negative Results ◽  
Contrast Enhanced ◽  
Arteriovenous Shunts ◽  
Arterial Feeder

OBJECT The object of this study was to evaluate the accuracy of fast 3D contrast-enhanced spinal MR angiography (MRA) using a manual syringe contrast injection technique for detecting and evaluating spinal arteriovenous shunts (AVSs). METHODS This was a retrospective study of 15 patients and 20 spinal MRA and catheter angiography studies. The accuracy of using spinal MRA to detect spinal AVS, localize shunts, and discriminate the subtype and dominant arterial feeder of the AVS were studied. RESULTS There were 14 pretherapeutic and 6 posttherapeutic follow-up spinal MRA and catheter spinal angiography studies. The spinal AVS was demonstrated in 17 of 20 studies. Spinal MRA demonstrated 100% sensitivity for detecting spinal AVS with no false-negative results. A 97% accuracy rate for AVS subtype discrimination and shunt level localization was achieved using this study's diagnostic criteria. The detection of the dominant arterial feeder was limited to 9 of these 17 cases (53%). CONCLUSIONS The fast 3D contrast-enhanced MRA technique performed using manual syringe contrast injection can detect the presence of a spinal AVS, locate the shunt level, and discriminate AVS subtype in most cases, but is limited when detecting small arterial feeders.

scholarly journals An Experimental Approach to Risk of Organ Rejection: Demonstration of False Immunosuppressant Results Due to Radiopaque Agents

2019 ◽  
Author(s):  
Ataman Gönel ◽  
Ismail Koyuncu
Keyword(s):  
Cyclosporine A ◽  
Experimental Approach ◽  
False Negative ◽  
Therapeutic Index ◽  
Blood Levels ◽  
Organ Rejection ◽  
Negative Results ◽  
False Negative Results ◽  
Contrast Enhanced ◽  
Target Values

Background: Immunosuppressant blood levels should be measured at regular periods in order to keep them within the therapeutic index. Although LC-MS/MS is preferred as a reliable method, some molecules like radiopaque agents in blood matrix may lead to false results. The aim of this study is to investigate the effect of seven different radiopaque agents on immunosuppressant drugs. Methods: Seven different radiopaque agents were added into control materials containing tacrolimus, everolimus, sirolimus and cyclosporine A drugs. Measurements were performed by LC-MS/MS instrument. The amount of deviations from target values were calculated. Results: Immunosuppressant blood levels significantly changed after the administration of radiopaque agents. Seven different radiopaque products led to false negative results in tacrolimus and cyclosporine A levels at a rate of 19.77% to 44.45%. The smallest deviations were seen in everolimus levels with administration of RM6 (gadodiamide) and in sirolimus levels with RM1 (gadobutrol) at rates of 4.04% and 2.11%, respectively. The highest deviations were observed with RM3 (iohexol) administration in everolimus and sirolimus levels at rates of 153.72% and 171.41%, respectively. Conclusions: False immunosuppressant results associated with radiopaque agents may result in organ rejection. Preferring radiopaque agents that cause the least interference risk is important to reduce the organ rejection risk. However, the least risky method is to obtain samples for drug levels before contrast-enhanced imaging.

Critical Evaluation of Impedance Phlebography for the Diagnosis of Deep Vein Thrombosis

1974 ◽  
Vol 31 (02) ◽  
pp. 273-278
Author(s):  
Kenneth K Wu ◽  
John C Hoak ◽  
Robert W Barnes ◽  
Stuart L Frankel
Keyword(s):  
Deep Vein Thrombosis ◽  
False Positive ◽  
False Negative ◽  
Critical Evaluation ◽  
Original Method ◽  
Vein Thrombosis ◽  
Negative Results ◽  
False Negative Results ◽  
Deep Vein ◽  
Positive Results

SummaryIn order to evaluate its daily variability and reliability, impedance phlebography was performed daily or on alternate days on 61 patients with deep vein thrombosis, of whom 47 also had 125I-fibrinogen uptake tests and 22 had radiographic venography. The results showed that impedance phlebography was highly variable and poorly reliable. False positive results were noted in 8 limbs (18%) and false negative results in 3 limbs (7%). Despite its being simple, rapid and noninvasive, its clinical usefulness is doubtful when performed according to the original method.

Scoring System for the Diagnosis of COVID-19

2020 ◽  
Vol 13 (1) ◽  
pp. 413-414 ◽  
Author(s):  
Mohamed Farouk Allam
Keyword(s):  
Scoring System ◽  
Clinical Symptoms ◽  
False Negative ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Negative Results ◽  
False Negative Results ◽  
Symptoms And Signs

Due to the international spread of COVID-19, the difficulty of collecting nasopharyngeal swab specimen from all suspected patients, the costs of RT-PCR and CT, and the false negative results of RT-PCR assay in 41% of COVID-19 patients, a scoring system is needed to classify the suspected patients in order to determine the need for follow-up, home isolation, quarantine or the conduction of further investigations. A scoring system is proposed as a diagnostic tool for suspected patients. It includes Epidemiological Evidence of Exposure, Clinical Symptoms and Signs, and Investigations (if available). This scoring system is simple, could be calculated in a few minutes, and incorporates the main possible data/findings of any patient.

Detection of Streptococcus pneumoniae in Sputum Samples by Real- Time PCR.

2020 ◽  
Vol 18 ◽  
Author(s):  
Pegah Shakib ◽  
Mohammad Reza Zolfaghari
Keyword(s):  
Streptococcus Pneumoniae ◽  
Real Time ◽  
Real Time Pcr ◽  
False Negative ◽  
Cross Sectional Study ◽  
Laboratory Culture ◽  
Cross Sectional ◽  
Negative Results ◽  
False Negative Results ◽  
Pcr Method

Background: Conventional laboratory culture-based methods for diagnosis of Streptococcus pneumoniae are time-consuming and yield false negative results. Molecular methods including real-time (RT)-PCR rapid methods and conventional PCR due to higher sensitivity and accuracy have been replaced instead traditional culture assay. The aim of the current study was to evaluate lytA gene for detection of Streptococcus pneumoniae in the cerebrospinal fluid of human patients with meningitis using real-time PCR assay. Material and Methods: In this cross-sectional study, a total of 30 clinical specimens were collected from patients in a period from September to December 2018. In order to evaluate the presence of lytA gene, conventional and real-time PCR methods were used without culture. Results: From 30 sputum samples five (16.66%) isolates were identified as S. pneumoniae by lytA PCR and sequencing. Discussion: In this research, an accurate and rapid real-time PCR method was used, which is based on lytA gene for diagnosis of bacteria so that it can be diagnosed. Based on the sequencing results, the sensitivity for detection of lytA gene was 100% (5/5).

COVID-19: how nuclear medicine can provide a differential diagnosis in very dubious case

Coronaviruses ◽  
2020 ◽  
Vol 01 ◽  
Author(s):  
Maria Silvia De Feo ◽  
Viviana Frantellizzi ◽  
Giuseppe De Vincentis
Keyword(s):  
Infectious Disease ◽  
Differential Diagnosis ◽  
Ct Scan ◽  
Imaging Technique ◽  
False Negative ◽  
Clinical Signs ◽  
Negative Results ◽  
Infectious Disease Department ◽  
False Negative Results ◽  
99Mtc Hmpao

Background: We present the case of a 55-year-old woman, admitted to the Infectious Disease Department of Policlinico Umberto I, Rome, in mid-March 2020, with suspicion of COVID-19 infection. Objective: The rRT-PCR was negative and the following CT scan, performed to exclude false-negative results and help diagnosis, was inconclusive. Methods: It was decided to submit the patient to 99mTc-HMPAO-labelled leukocyte scan. Results: This exam led to the diagnosis of infective endocarditis. Conclusion: In the present pandemic scenario, 99mTc-HMPAO-labelled leukocyte scan represents a reliable imaging technique for differential diagnosis with COVID-19 in patients with confusing clinical signs, possible false-negative rRT-PCR results and inconclusive CT scan.

Sign in / Sign up

Export Citation Format

Share Document