Comparison of Positive Predictive Values of Biparametric MRI and Multiparametric MRI-directed Transrectal US-guided Targeted Prostate Biopsy.

Background Biparametric MRI (bpMRI) of the prostate is an alternative to multiparametric MRI (mpMRI), with lower cost and increased accessibility. Studies investigating the positive predictive value (PPV) of bpMRI-directed compared with mpMRI-directed targeted biopsy are lacking in the literature. Purpose To compare the PPVs of bpMRI-directed and mpMRI-directed targeted prostate biopsies. Materials and Methods This retrospective cross-sectional study evaluated men who underwent bpMRI-directed or mpMRI-directed transrectal US (TRUS)-guided targeted prostate biopsy at a single institution from January 2015 to December 2022. The PPVs for any prostate cancer (PCa) and clinically significant PCa (International Society of Urological Pathology grade ≥2) were calculated for bpMRI and mpMRI using mixed-effects logistic regression modeling. Results A total of 1538 patients (mean age, 67 years ± 8 [SD]) with 1860 lesions underwent bpMRI-directed (55%, 849 of 1538) or mpMRI-directed (45%, 689 of 1538) prostate biopsy. When adjusted for the number of lesions and Prostate Imaging Reporting and Data System (PI-RADS) score, there was no difference in PPVs for any PCa or clinically significant PCa (P = .61 and .97, respectively) with bpMRI-directed (55% [95% CI: 51, 59] and 34% [95% CI: 30, 38], respectively) or mpMRI-directed (56% [95% CI: 52, 61] and 34% [95% CI: 30, 39], respectively) TRUS-guided targeted biopsy. PPVs for any PCa and clinically significant PCa stratified according to clinical indication were as follows: biopsy-naive men, 64% (95% CI: 59, 69) and 43% (95% CI: 39, 48) for bpMRI, 67% (95% CI: 59, 75) and 51% (95% CI: 43, 59) for mpMRI (P = .65 and .26, respectively); and active surveillance, 59% (95% CI: 49, 69) and 30% (95% CI: 22, 39) for bpMRI, 73% (95% CI: 65, 89) and 38% (95% CI: 31, 47) for mpMRI (P = .04 and .23, respectively). Conclusion There was no evidence of a difference in PPV for clinically significant PCa between bpMRI- and mpMRI-directed TRUS-guided targeted biopsy. © RSNA, 2024 Supplemental material is available for this article.

Proportion of malignancy in Bosniak classification of cystic renal masses version 2019 (v2019) classes: systematic review and meta-analysis.

OBJECTIVES: Determine the proportion of malignancy within Bosniak v2019 classes. METHODS: MEDLINE and EMBASE were searched. Eligible studies contained patients with cystic renal masses undergoing CT or MRI renal protocol examinations with pathology confirmation, applying Bosniak v2019. Proportion of malignancy was estimated within Bosniak v2019 class. Risk of bias was assessed using QUADAS-2. RESULTS: We included 471 patients with 480 cystic renal masses. No class I malignant masses were observed. Pooled proportion of malignancy were class II, 12% (6/51, 95% CI 5-24%); class IIF, 46% (37/85, 95% CI 28-66%); class III, 79% (138/173, 95% CI 68-88%); and class IV, 84% (114/135, 95% CI 77-90%). Proportion of malignancy differed between Bosniak v2019 II-IV classes (p = 0.004). Four studies reported the proportion of malignancy by wall/septa feature. The pooled proportion of malignancy with 95% CI were class III thick smooth wall/septa, 77% (41/56, 95% CI 53-91%); class III obtuse protrusion ≤ 3 mm (irregularity), 83% (97/117, 95% CI 75-89%); and class IV nodule with acute angulation, 86% (50/58, 95% CI 75-93%) or obtuse angulation ≥ 4 mm, 83%, (64/77, 95% CI 73-90%). Subgroup analysis by wall/septa feature was limited by sample size; however, no differences were found comparing class III masses with irregularity to class IV masses (p = 0.74) or between class IV masses by acute versus obtuse angles (p = 0.62). CONCLUSION: Preliminary data suggest Bosniak v2019 class IIF masses have higher proportion of malignancy compared to the original classification, controlling for pathologic reference standard. There are no differences in proportion of malignancy comparing class III masses with irregularities to class IV masses with acute or obtuse nodules. KEY POINTS: • The proportion of malignancy in Bosniak v2019 class IIF cystic masses is 46% (37 malignant/85 total IIF masses, 95% confidence intervals (CI) 28-66%). • The proportion of malignancy in Bosniak v2019 class III cystic masses is 79% (138/173, 95% CI 68-88%) and in Bosniak v2019 class IV cystic masses is 84% (114/135, 95% CI 77-90%). • Class III cystic masses with irregularities had similar proportion of malignancy (83%, 97/117, 95% CI 75-89%) compared to Bosniak class IV masses (84%, 114/135, 95% CI 77-90%) overall (p = 0.74) with no difference within class IV masses by acute versus obtuse angulation (p = 0.62).

Adverse Events Associated with Intra-Arterial Administration of Gadolinium-Based Contrast Agents: A Systematic Review and Meta-Analysis.

PURPOSE: To determine the risk of immediate hypersensitivity reactions (HRs), contrast-associated acute kidney injury (CA-AKI), nephrogenic systemic fibrosis (NSF), and gadolinium retention associated with use of intra-arterial gadolinium-based contrast agents (GBCAs). MATERIALS AND METHODS: MEDLINE, Embase, and Cochrane Central Register of Controlled Trials were searched from 1988 (GBCAs approved for clinical use) to March 2021 for studies reporting adverse events associated with intra-arterial administration of GBCAs. The number of adverse events and GBCA administrations were used to calculate incidence in individual studies, and results across studies were pooled using random-effects meta-analysis. RESULTS: There were 72 studies (patients = 1,221) that reported on HR, 59 studies (patients = 1,142) that reported on CA-AKI, and 6 studies (patients = 291) that reported on NSF. No studies reported gadolinium retention as an outcome. Based on 5 events and 1,451 GBCA administrations, the incidence of HR per 100 administrations was 0.95 (95% CI, 0.52-1.51). Based on 90 events and 1,318 GBCA administrations, the incidence of CA-AKI per 100 administrations was 5.94 (95% CI, 3.92-8.34). Based on 7 events and 361 GBCA administrations, the incidence of NSF per 100 Group I GBCA administrations was 4.72 (95% CI, 0.35-13.70). There were no unconfounded NSF events after Group II GBCA administration. CONCLUSIONS: HRs to intra-arterial administration of GBCAs are rare, with no serious reactions. Limited data demonstrate a higher-than-expected rate of CA-AKI; however, multiple confounding factors were noted. Thus, any causative link of CA-AKI to GBCA remains controversial. Also, severe physiologic reactions (including life-threatening arrhythmias) during coronary angiography have been reported.

Association of Accuracy, Conclusions, and Reporting Completeness With Acceptance by Radiology Conferences and Journals.

BACKGROUND: Preferential publication of studies with positive findings can lead to overestimation of diagnostic test accuracy (i.e. publication bias). Understanding the contribution of the editorial process to publication bias could inform interventions to optimize the evidence guiding clinical decisions. PURPOSE/HYPOTHESIS: To evaluate whether accuracy estimates, abstract conclusion positivity, and completeness of abstract reporting are associated with acceptance to radiology conferences and journals. STUDY TYPE: Meta-research. POPULATION: Abstracts submitted to radiology conferences (European Society of Gastrointestinal and Abdominal Radiology (ESGAR) and International Society for Magnetic Resonance in Medicine (ISMRM)) from 2008 to 2018 and manuscripts submitted to radiology journals (Radiology, Journal of Magnetic Resonance Imaging [JMRI]) from 2017 to 2018. Primary clinical studies evaluating sensitivity and specificity of a diagnostic imaging test in humans with available editorial decisions were included. ASSESSMENT: Primary variables (Youden's index [YI > 0.8 vs. <0.8], abstract conclusion positivity [positive vs. neutral/negative], number of reported items on the Standards for Reporting of Diagnostic Accuracy Studies [STARD] for Abstract guideline) and confounding variables (prospective vs. retrospective/unreported, sample size, study duration, interobserver agreement assessment, subspecialty, modality) were extracted. STATISTICAL TESTS: Multivariable logistic regression to obtain adjusted odds ratio (OR) as a measure of the association between the primary variables and acceptance by radiology conferences and journals; 95% confidence intervals (CIs) and P-values were obtained; the threshold for statistical significance was P < 0.05. RESULTS: A total of 1000 conference abstracts (500 ESGAR and 500 ISMRM) and 1000 journal manuscripts (505 Radiology and 495 JMRI) were included. Conference abstract acceptance was not significantly associated with YI (adjusted OR = 0.97 for YI > 0.8; CI = 0.70-1.35), conclusion positivity (OR = 1.21 for positive conclusions; CI = 0.75-1.90) or STARD for Abstracts adherence (OR = 0.96 per unit increase in reported items; CI = 0.82-1.18). Manuscripts with positive abstract conclusions were less likely to be accepted by radiology journals (OR = 0.45; CI = 0.24-0.86), while YI (OR = 0.85; CI = 0.56-1.29) and STARD for Abstracts adherence (OR = 1.06; CI = 0.87-1.30) showed no significant association. Positive conclusions were present in 86.7% of submitted conference abstracts and 90.2% of journal manuscripts. DATA CONCLUSION: Diagnostic test accuracy studies with positive findings were not preferentially accepted by the evaluated radiology conferences or journals. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 2.

Direct Comparison of Diagnostic Accuracy of Fast Kilovoltage Switching Dual-Energy Computed Tomography and Magnetic Resonance Imaging for Detection of Enhancement in Renal Masses.

PURPOSE: The aim of the study was to compare diagnostic accuracy of dual-energy computed tomography (DECT) and magnetic resonance imaging (MRI) to detect enhancement in renal masses. METHODS: Adults renal masses of 10 mm or greater with both fast kilovoltage potential switching DECT and contrast-enhanced MRI performed within 12 months were retrospectively included. Two blinded radiologists independently evaluated for enhancement subjectively (5-point Likert scales) and quantitatively (signal intensity ratio ≥15% for MRI, iodine concentration ≥1.2 or ≥2.0 mg/mL for DECT). Per-lesion diagnostic accuracy, with histologic reference standard for solid masses, was expressed as the area under the receiver operator curve (AUC) for each index test. Differences were evaluated for statistical significance using the DeLong test. RESULTS: We included 24 patients with 41 masses: 17 solid renal masses and 24 Bosniak 1 or 2 cysts. There was no significant difference in diagnostic accuracy comparing subjective enhancement by MRI and using iodine overlay DECT for reader 1 (AUC 0.99 vs 0.99, P = 0.38) or reader 2 (AUC 1.00 vs 0.94, P = 0.12) Interobserver agreement was κ = 0.61 for DECT and κ = 0.71 for MRI. There was no significant difference either in accuracy between quantitative assessment using signal intensity ratio or iodine concentration for reader 1 (AUC 0.94 vs 0.94, P = 0.88) or reader 2 (AUC 0.97 vs 0.92, P = 0.16). False-negative results in both subjective and quantitative assessment were nearly exclusively seen in papillary renal cell carcinoma, occurring with both DECT and MRI. CONCLUSIONS: We detected no significant differences in accuracy for detecting enhancement in renal masses comparing MRI and DECT. Our results require further investigation in larger sample sizes, but suggest that DECT may be comparable to MRI for detection of enhancement in renal masses.

Safety of Off-Label Use of Ferumoxtyol as a Contrast Agent for MRI: A Systematic Review and Meta-Analysis of Adverse Events.

BACKGROUND: Ferumoxytol has been studied as an alternative to gadolinium-based MRI contrast agents, but regulatory body warnings currently limit its use. PURPOSE: Estimate the adverse event rate in patients undergoing MRI with ferumoxytol as a contrast agent. STUDY TYPE: Systematic review. POPULATION: Thirty-nine studies including 5411 ferumoxytol administrations in 4336 patients. ASSESSMENT: Multiple databases were searched for studies using ferumoxytol as an off-label MRI contrast agent in any patient population as of April 2020. Studies were eligible for inclusion if they reported the number and severity of adverse events (classified by American College of Radiology [ACR] severity of acute reactions). Risk of bias was assessed using the ROBINS-I tool. STATISTICAL TESTS: The proportion of administrations with adverse events was calculated using random effects meta-analysis of proportions. RESULTS: No deaths related to ferumoxytol administration were reported. Sixteen studies reported immediate adverse events in 3849 patients undergoing 4901 ferumoxytol administrations. Ninety-seven immediate adverse events were reported and the pooled adverse event proportion for immediate adverse events was 0.02 (95% confidence interval [CI] 0.02-0.02). Twenty-three studies reported time-unspecified adverse events in 487 patients undergoing 510 ferumoxytol administrations. Five time-unspecified adverse events were reported; the pooled adverse event proportion for time-unspecified adverse events was 0.01 (95% CI 0.00-0.04). 88% of adverse events were mild (90/102), 11% (11/102) were moderate, and 1% (1/102) was severe. Sixteen studies were at low risk of bias, 23 studies were at serious risk of bias. Subgroup analysis by patient population revealed no significant variability (adult vs. pediatric). No studies evaluated the use of ferumoxytol as an alternative to patients who had a prior hypersensitivity reaction to gadolinium-based contrast agents (GBCAs). DATA CONCLUSION: The overall adverse event rate for off-label ferumoxytol use as an MRI contrast agent is 2%, with rare severe reactions and no deaths. To date, there are no studies evaluating the safety of ferumoxytol as an alternative to GBCAs in patients with a prior hypersensitivity reaction. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 5.

Diagnostic accuracy of dual-energy CT for the detection of bone marrow edema in the appendicular skeleton: a systematic review and meta-analysis.

OBJECTIVES: This meta-analysis evaluated the diagnostic accuracy of dual-energy CT (DECT) for detecting bone marrow edema (BME) in the appendicular skeleton. METHODS: A systematic review of MEDLINE, EMBASE, Scopus, the Cochrane Library, and gray literature from inception through January 31, 2020, was performed. Original articles with > 10 patients evaluating the accuracy of DECT for detecting BME in the appendicular skeleton with a reference standard of MRI and/or clinical follow-up were included. Study details were independently extracted by two reviewers. Meta-analysis was performed using a bivariate random-effects model with multivariable meta-regression. Risk of bias (RoB) was evaluated with QUADAS-2. RESULTS: Twenty studies evaluating 790 patients for BME in the appendicular skeleton were included in analysis. The summary sensitivity, specificity, and AUC values for BME in the appendicular skeleton were 86% (95% confidence interval [CI] 82-89%), 93% (95% CI 90-95%), and 0.95, respectively. Quantitative analysis had a higher sensitivity than qualitative analysis on meta-regression (p = 0.01), but no difference in specificity (p = 0.28). No other covariates contributed to variability in accuracy (etiology (trauma vs non-trauma); location (upper vs lower extremity); and RoB). Studies demonstrated generally low or unclear RoB and applicability. Eight studies included index tests with high RoB when quantitative assessments used a retrospective cut-off value. CONCLUSIONS: DECT demonstrates a higher specificity than sensitivity and AUC > 0.9. In scenarios where MRI availability is limited or contraindicated, DECT could be an alternative to MRI for detecting BME in the appendicular skeleton. However, limitations in sources of variability and RoB warrant continued study. KEY POINTS: • Twenty studies evaluating 790 patients for bone marrow edema in the appendicular skeleton with dual-energy CT were included in analysis. • The summary sensitivity, specificity, and AUC values for detecting bone marrow in the appendicular skeleton were 86% (95% confidence interval [CI] 82-89%), 93% (95% CI 90-95%), and 0.95, respectively. • In scenarios where MRI availability is limited or is contraindicated, DECT could be an alternative to MRI for detecting bone marrow edema in the appendicular skeleton.

Reporting Bias in Imaging Diagnostic Test Accuracy Studies: Are Studies With Positive Conclusions or Titles Submitted and Published Faster?

OBJECTIVE: The purpose of this study is to evaluate whether imaging diagnostic test accuracy (DTA) studies with positive conclusions or titles have a shorter time to publication than those with nonpositive (i.e., negative or neutral) conclusions or titles. MATERIALS AND METHODS: We included primary imaging DTA studies from systematic reviews published in 2015. The conclusion and title of each study were extracted, and their positivity was classified independently in duplicate. The time from study completion to publication was extracted and calculated. A Cox regression model was used to evaluate associations of conclusion and title positivity with time to publication, with adjustment made for potentially confounding variables. RESULTS: A total of 774 imaging DTA studies were included; time from study completion to publication could be calculated for 516 studies. The median time from completion to publication was 18 months (interquartile range, 13-26 months) for the 413 studies with positive conclusions, 23 months (interquartile range, 16-33 months) for the 63 studies with neutral conclusions, and 25 months (interquartile range, 15-38 months) for the 40 studies with negative conclusions. A positive conclusion was associated with a shorter time from study completion to publication compared with a non-positive conclusion (hazard ratio, 1.31; 95% CI, 1.02-1.68). Of all included studies, 39 (5%) had positive titles, 731 (94%) had neutral titles, and 4 (< 1%) had negative titles. Positive titles were not significantly associated with a shorter time to study publication (hazard ratio, 1.12; 95% CI, 0.75-1.69). CONCLUSION: Positive conclusions (but not titles) were associated with a shorter time from study completion to publication. This finding may contribute to an overrepresentation of positive results in the imaging DTA literature.

Accuracy of the Liver Imaging Reporting and Data System in Computed Tomography and Magnetic Resonance Image Analysis of Hepatocellular Carcinoma or Overall Malignancy-A Systematic Review.

BACKGROUND & AIMS: The Liver Imaging Reporting and Data System (LI-RADS) categorizes observations from imaging analyses of high-risk patients based on the level of suspicion for hepatocellular carcinoma (HCC) and overall malignancy. The categories range from definitely benign (LR-1) to definitely HCC (LR-5), malignancy (LR-M), or tumor in vein (LR-TIV) based on findings from computed tomography or magnetic resonance imaging. However, the actual percentage of HCC and overall malignancy within each LI-RADS category is not known. We performed a systematic review to determine the percentage of observations in each LI-RADS category for computed tomography and magnetic resonance imaging that are HCCs or malignancies. METHODS: We searched the MEDLINE, Embase, Cochrane CENTRAL, and Scopus databases from 2014 through 2018 for studies that reported the percentage of observations in each LI-RADS v2014 and v2017 category that were confirmed as HCCs or other malignancies based on pathology, follow-up imaging analyses, or response to treatment (reference standard). Data were assessed on a per-observation basis. Random-effects models were used to determine the pooled percentages of HCC and overall malignancy for each LI-RADS category. Differences between categories were compared by analysis of variance of logit-transformed percentage of HCC and overall malignancy. Risk of bias and concerns about applicability were assessed with the Quality Assessment of Diagnostic Accuracy Studies 2 tool. RESULTS: Of 454 studies identified, 17 (all retrospective studies) were included in the final analysis, consisting of 2760 patients, 3556 observations, and 2482 HCCs. The pooled percentages of observations confirmed as HCC and overall malignancy, respectively, were 94% (95% confidence interval [CI] 92%-96%) and 97% (95% CI 95%-99%) for LR-5, 74% (95% CI 67%-80%) and 80% (95% CI 75%-85%) for LR-4, 38% (95% CI 31%-45%) and 40% (95% CI 31%-50%) for LR-3, 13% (95% CI 8%-22%) and 14% (95% CI 9%-21%) for LR-2, 79% (95% CI 63%-89%) and 92% (95% CI 77%-98%) for LR-TIV, and 36% (95% CI 26%-48%) and 93% (95% CI 87%-97%) for LR-M. No malignancies were found in the LR-1 group. The percentage of HCCs and overall malignancies confirmed differed significantly among LR groups 2-5 (P < .00001). Patient selection was the most frequent factor that affected bias risk, because of verification bias and case-control study design. CONCLUSIONS: In a systematic review, we found that increasing LI-RADS categories contained increasing percentages of HCCs and overall malignancy based on reference standard confirmation. Of observations categorized as LR-M, 93% were malignancies and 36% were confirmed as HCCs. The percentage of HCCs found in the LR-2 and LR-3 categories indicate the need for a more active management strategy than currently recommended. Prospective studies are needed to validate these findings. PROSPERO number CRD42018087441.

Breakthrough Hypersensitivity Reactions to Gadolinium-based Contrast Agents and Strategies to Decrease Subsequent Reaction Rates: A Systematic Review and Meta-Analysis.

Background Hypersensitivity reactions to gadolinium-based contrast agents (GBCAs) that occur despite corticosteroid premedication (breakthrough reactions) are not well understood. Purpose To determine the GBCA breakthrough reaction rate overall and according to GBCA class and to determine the effect of using an alternative GBCA or allergy skin testing on the risk of a breakthrough reaction. Materials and Methods In this systematic review and meta-analysis, MEDLINE (from 1946 to 2019), Embase (from 1947 to 2019), and the Cochrane Central Register of Controlled Trials (2019 only) were searched for patients with a breakthrough reaction to a GBCA who were undergoing repeat GBCA administration. Breakthrough reaction rates were determined with random-effects modeling and meta-regression. Secondary analyses of GBCA class, switching to an alternative GBCA, and allergy skin testing were assessed. Quality Assessment of Diagnostic Accuracy Studies 2 was used to determine risk of bias and applicability. Percentages are meta-regression results and do not directly reflect raw data. Results Of the 148 identified studies, 23 were included, encompassing 120 patients and 130 GBCA administrations. The overall breakthrough reaction rate was 39% (95% confidence interval [CI]: 30%, 49%; 37 of 103 administrations). Breakthrough reaction rates for macrocyclic (36%; 95% CI: 25%, 48%; 23 of 64 administrations) and protein-binding linear (31%; 95% CI: 1%, 94%; [one of seven administrations) GBCAs did not differ (P = .90). There were insufficient analyzable data for gadodiamide, gadoversetamide, and gadopentetate. Hypersensitivity reaction rate after switching GBCAs was 50% (95% CI: 21%, 79%; three of nine administrations) with and 71% (95% CI: 21%, 95%; four of five administrations) without corticosteroid premedication, which did not differ (P = .82 and P = .17, respectively) from the observed rate when using corticosteroid premedication and the same GBCA (36%; 95% CI: 26%, 48%; 37 of 84 administrations). Hypersensitivity reaction rate after allergy skin testing (17%; 95% CI: 7%, 29%; zero of 21 studies) did not differ when compared with use of the same agent with corticosteroid premedication (P = .10). Meta-analysis limitations were the small number of patients and the high risk of bias. Conclusion Patients with a prior hypersensitivity reaction to a gadolinium-based contrast agent (GBCA) often had breakthrough reactions. The effect of switching to an alternative GBCA or using allergy skin testing to decrease reaction risk lacked enough available data for meaningful comparisons. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Prince in this issue.

Overinterpretation of Research Findings: Evaluation of "Spin" in Systematic Reviews of Diagnostic Accuracy Studies in High-Impact Factor Journals.

BACKGROUND: To compare the frequency of "spin" in systematic reviews of diagnostic accuracy studies in high-impact journals with the frequency a previously assessed series of reviews. METHODS: Medline was searched from January 2010 to January 2019. Systematic reviews of diagnostic accuracy studies were included if they reported a meta-analysis and were published in a journal with an impact factor >5. Two investigators independently scored each included systematic review for positivity of conclusions and for actual and potential overinterpretation practices. RESULTS: Of 137 included systematic reviews, actual overinterpretation was present in ≥1 form in the abstract in 63 (46%) and in the full-text report in 52 (38%); 108 (79%) contained a form of potential overinterpretation. Compared with the previously assessed series (reviews published 2015-2016), reviews in this series were less likely to contain ≥1 form of actual overinterpretation in the abstract and full-text report or ≥1 form of potential overinterpretation (P < 0.001 for all comparisons). The significance of these comparisons did not persist for actual overinterpretation in sensitivity analysis in which Cochrane systematic reviews were removed. Reviews published in the Cochrane Database of Systematic Reviews were less likely to contain actual overinterpretation in the abstract or the full-text report than reviews in other high-impact journals (P < 0.001 for both comparisons). CONCLUSIONS: Reviews of diagnostic accuracy studies in high-impact journals are less likely to contain overinterpretation or spin. This difference is largely due to the reviews published in the Cochrane Database of Systematic Reviews, which contain spin less often than reviews published in other high-impact journals.

Diagnostic accuracy of dual-energy computed tomography (DECT) to differentiate uric acid from non-uric acid calculi: systematic review and meta-analysis.

BACKGROUND: Uric acid stone diagnosis is presently done primarily with in vitro analysis of stones. In vivo diagnosis with dual-energy CT (DECT) would allow earlier initiation of therapy with urine alkalinization and avoid surgical intervention. OBJECTIVE: To evaluate if DECT, using stone analysis as reference standard, is sufficiently accurate to replace stone analysis for diagnosis of uric acid stones. METHODS: Original studies in patients with urolithiasis examined with DECT with stone analysis as the reference standard were eligible for inclusion. MEDLINE (1946-2018), Embase (1947-2018), CENTRAL (August 2018), and multiple urology and radiology conferences were searched. QUADAS-2 was used to assess risk of bias and applicability. Meta-analyses were performed using a bivariate random-effects model. RESULTS: A total of 21 studies (1105 patients, 1442 stones) were included. Fourteen studies containing 662 patients (944 stones) were analyzed in the uric acid dominant target condition (majority of stone composition uric acid): mean sensitivity was 0.88 (95% CI 0.79-0.93) and specificity 0.98 (95% CI 0.96-0.99). Thirteen studies (674 patients, 760 stones) were analyzed in the uric acid-containing target condition (< majority of stone composition uric acid): mean sensitivity was 0.82 (95% CI 0.73-0.89) and specificity 0.97 (95% CI 0.94-0.98). Meta-regression showed no significant variability in test accuracy. Two studies had one or more domains at high risk of bias and there were no concerns regarding applicability. CONCLUSION: DECT is an accurate replacement test for diagnosis of uric acid calculi in vivo, such that stone analysis could be replaced in the diagnostic pathway. This would enable earlier initiation of urine alkalinization. KEY POINTS: • DECT for uric acid dominant stones has sensitivity of 0.88 (95% CI 0.79-0.93) and specificity of 0.98 (95% CI 0.96-0.99); uric acid-containing stones had mean sensitivity of 0.82 (95% CI 0.73-0.89) and specificity of 0.97 (95% CI 0.94-0.98). • Meta-regression did not identify any variables (study design, reference standard, dual-energy CT type, dose, risk of bias) that influenced test accuracy. • Only 2 of the 21 included studies had 1 or more domain considered to be at high risk of bias with the majority of domains considered at low risk of bias; there were no concerns regarding applicability in any of the included studies.

Publication bias in diagnostic imaging: conference abstracts with positive conclusions are more likely to be published.

OBJECTIVE: To evaluate whether imaging diagnostic test accuracy conference abstracts with positive conclusions or titles are more likely to reach full-text publication than those with negative (or neutral) conclusions or titles. METHODS: Diagnostic accuracy research abstracts were included if they were presented at the 2011 or 2012 Radiological Society of North America conference. Full-text publication status at 5 years post conference abstract submission was determined. Conclusion and title positivity of conference abstracts were extracted, as well as potential confounding factors. The associations of conclusion and title positivity with publication status at 5 years post conference abstract submission were assessed using a multivariable logistic regression model. Conditional odds ratios were calculated to express the strength of associations, adjusting for the confounders. RESULTS: In total, 282/400 (71%) of included conference abstracts reached full-text publication. A total of 246 out of 337 (74%) conference abstracts with positive conclusions resulted in full-text publications, compared with 26/48 (54%) with neutral conclusions and 5/15 (33%) with negative conclusions. In multivariable logistic regression, conclusion positivity was significantly associated with full-text publication (odds ratio 3.6; 95% CI 1.9-6.7 for conference abstracts with positive conclusions, compared with those with non-positive conclusions); this did not apply to title positivity (odds ratio 1.2; 95% CI 0.47-3.0). CONCLUSION: Imaging conference abstracts with positive conclusions were more likely to be published as full-text articles. Title positivity was not associated with publication. This preferential publication pattern may lead to an overrepresentation of positive studies in the literature. An overrepresentation of positive studies may contribute to inflated estimates of test accuracy and has the potential to adversely influence patient care. KEY POINTS: • Imaging diagnostic test accuracy conference abstracts with positive conclusions were more likely to be reported as full-text articles than those with non-positive conclusions. • The majority (75%) of imaging diagnostic test accuracy conference abstracts with positive conclusions were published, compared with only 53% and 33% with neutral and negative conclusions, respectively. • Conclusion positivity remained associated with the full-text publication of conference abstracts when controlling for multiple potential confounding variables.

Thoracic imaging tests for the diagnosis of COVID-19.

BACKGROUND: The diagnosis of infection by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presents major challenges. Reverse transcriptase polymerase chain reaction (RT-PCR) testing is used to diagnose a current infection, but its utility as a reference standard is constrained by sampling errors, limited sensitivity (71% to 98%), and dependence on the timing of specimen collection. Chest imaging tests are being used in the diagnosis of COVID-19 disease, or when RT-PCR testing is unavailable. OBJECTIVES: To determine the diagnostic accuracy of chest imaging (computed tomography (CT), X-ray and ultrasound) in people with suspected or confirmed COVID-19. SEARCH METHODS: We searched the COVID-19 Living Evidence Database from the University of Bern, the Cochrane COVID-19 Study Register, and The Stephen B. Thacker CDC Library. In addition, we checked repositories of COVID-19 publications. We did not apply any language restrictions. We conducted searches for this review iteration up to 5 May 2020. SELECTION CRITERIA: We included studies of all designs that produce estimates of test accuracy or provide data from which estimates can be computed. We included two types of cross-sectional designs: a) where all patients suspected of the target condition enter the study through the same route and b) where it is not clear up front who has and who does not have the target condition, or where the patients with the target condition are recruited in a different way or from a different population from the patients without the target condition. When studies used a variety of reference standards, we included all of them. DATA COLLECTION AND ANALYSIS: We screened studies and extracted data independently, in duplicate. We also assessed the risk of bias and applicability concerns independently, in duplicate, using the QUADAS-2 checklist and presented the results of estimated sensitivity and specificity, using paired forest plots, and summarised in tables. We used a hierarchical meta-analysis model where appropriate. We presented uncertainty of the accuracy estimates using 95% confidence intervals (CIs). MAIN RESULTS: We included 84 studies, falling into two categories: studies with participants with confirmed diagnoses of COVID-19 at the time of recruitment (71 studies with 6331 participants) and studies with participants suspected of COVID-19 (13 studies with 1948 participants, including three case-control studies with 549 cases and controls). Chest CT was evaluated in 78 studies (8105 participants), chest X-ray in nine studies (682 COVID-19 cases), and chest ultrasound in two studies (32 COVID-19 cases). All evaluations of chest X-ray and ultrasound were conducted in studies with confirmed diagnoses only. Twenty-five per cent (21/84) of all studies were available only as preprints, 15/71 studies in the confirmed cases group and 6/13 of the studies in the suspected group. Among 71 studies that included confirmed cases, 41 studies had included symptomatic cases only, 25 studies had included cases regardless of their symptoms, five studies had included asymptomatic cases only, three of which included a combination of confirmed and suspected cases. Seventy studies were conducted in Asia, 2 in Europe, 2 in North America and one in South America. Fifty-one studies included inpatients while the remaining 24 studies were conducted in mixed or unclear settings. Risk of bias was high in most studies, mainly due to concerns about selection of participants and applicability. Among the 13 studies that included suspected cases, nine studies were conducted in Asia, and one in Europe. Seven studies included inpatients while the remaining three studies were conducted in mixed or unclear settings. In studies that included confirmed cases the pooled sensitivity of chest CT was 93.1% (95%CI: 90.2 - 95.0 (65 studies, 5759 cases); and for X-ray 82.1% (95%CI: 62.5 to 92.7 (9 studies, 682 cases). Heterogeneity judged by visual assessment of the ROC plots was considerable. Two studies evaluated the diagnostic accuracy of point-of-care ultrasound and both reported zero false negatives (with 10 and 22 participants having undergone ultrasound, respectively). These studies only reported True Positive and False Negative data, therefore it was not possible to pool and derive estimates of specificity. In studies that included suspected cases, the pooled sensitivity of CT was 86.2% (95%CI: 71.9 to 93.8 (13 studies, 2346 participants) and specificity was 18.1% (95%CI: 3.71 to 55.8). Heterogeneity judged by visual assessment of the forest plots was high. Chest CT may give approximately the same proportion of positive results for patients with and without a SARS-CoV-2 infection: the chances of getting a positive CT result are 86% (95% CI: 72 to 94) in patient with a SARS-CoV-2 infection and 82% (95% CI: 44 to 96) in patients without. AUTHORS' CONCLUSIONS: The uncertainty resulting from the poor study quality and the heterogeneity of included studies limit our ability to confidently draw conclusions based on our results. Our findings indicate that chest CT is sensitive but not specific for the diagnosis of COVID-19 in suspected patients, meaning that CT may not be capable of differentiating SARS-CoV-2 infection from other causes of respiratory illness. This low specificity could also be the result of the poor sensitivity of the reference standard (RT-PCR), as CT could potentially be more sensitive than RT-PCR in some cases. Because of limited data, accuracy estimates of chest X-ray and ultrasound of the lungs for the diagnosis of COVID-19 should be carefully interpreted. Future diagnostic accuracy studies should avoid cases-only studies and pre-define positive imaging findings. Planned updates of this review will aim to: increase precision around the accuracy estimates for CT (ideally with low risk of bias studies); obtain further data to inform accuracy of chest X rays and ultrasound; and continue to search for studies that fulfil secondary objectives to inform the utility of imaging along different diagnostic pathways.

Thoracic imaging tests for the diagnosis of COVID-19.

BACKGROUND: The respiratory illness caused by SARS-CoV-2 infection continues to present diagnostic challenges. Early research showed thoracic (chest) imaging to be sensitive but not specific in the diagnosis of coronavirus disease 2019 (COVID-19). However, this is a rapidly developing field and these findings need to be re-evaluated in the light of new research. This is the first update of this 'living systematic review'. This update focuses on people suspected of having COVID-19 and excludes studies with only confirmed COVID-19 participants. OBJECTIVES: To evaluate the diagnostic accuracy of thoracic imaging (computed tomography (CT), X-ray and ultrasound) in people with suspected COVID-19. SEARCH METHODS: We searched the COVID-19 Living Evidence Database from the University of Bern, the Cochrane COVID-19 Study Register, The Stephen B. Thacker CDC Library, and repositories of COVID-19 publications through to 22 June 2020. We did not apply any language restrictions. SELECTION CRITERIA: We included studies of all designs that recruited participants of any age group suspected to have COVID-19, and which reported estimates of test accuracy, or provided data from which estimates could be computed. When studies used a variety of reference standards, we retained the classification of participants as COVID-19 positive or negative as used in the study. DATA COLLECTION AND ANALYSIS: We screened studies, extracted data, and assessed the risk of bias and applicability concerns using the QUADAS-2 domain-list independently, in duplicate. We categorised included studies into three groups based on classification of index test results: studies that reported specific criteria for index test positivity (group 1); studies that did not report specific criteria, but had the test reader(s) explicitly classify the imaging test result as either COVID-19 positive or negative (group 2); and studies that reported an overview of index test findings, without explicitly classifying the imaging test as either COVID-19 positive or negative (group 3). We presented the results of estimated sensitivity and specificity using paired forest plots, and summarised in tables. We used a bivariate meta-analysis model where appropriate. We presented uncertainty of the accuracy estimates using 95% confidence intervals (CIs). MAIN RESULTS: We included 34 studies: 30 were cross-sectional studies with 8491 participants suspected of COVID-19, of which 4575 (54%) had a final diagnosis of COVID-19; four were case-control studies with 848 cases and controls in total, of which 464 (55%) had a final diagnosis of COVID-19. Chest CT was evaluated in 31 studies (8014 participants, 4224 (53%) cases), chest X-ray in three studies (1243 participants, 784 (63%) cases), and ultrasound of the lungs in one study (100 participants, 31 (31%) cases). Twenty-six per cent (9/34) of all studies were available only as preprints. Nineteen studies were conducted in Asia, 10 in Europe, four in North America and one in Australia. Sixteen studies included only adults, 15 studies included both adults and children and one included only children. Two studies did not report the ages of participants. Twenty-four studies included inpatients, four studies included outpatients, while the remaining six studies were conducted in unclear settings. The majority of included studies had a high or unclear risk of bias with respect to participant selection, index test, reference standard, and participant flow. For chest CT in suspected COVID-19 participants (31 studies, 8014 participants, 4224 (53%) cases) the sensitivity ranged from 57.4% to 100%, and specificity ranged from 0% to 96.0%. The pooled sensitivity of chest CT in suspected COVID-19 participants was 89.9% (95% CI 85.7 to 92.9) and the pooled specificity was 61.1% (95% CI 42.3 to 77.1). Sensitivity analyses showed that when the studies from China were excluded, the studies from other countries demonstrated higher specificity compared to the overall included studies. When studies that did not classify index tests as positive or negative for COVID-19 (group 3) were excluded, the remaining studies (groups 1 and 2) demonstrated higher specificity compared to the overall included studies. Sensitivity analyses limited to cross-sectional studies, or studies where at least two reverse transcriptase polymerase chain reaction (RT-PCR) tests were conducted if the first was negative, did not substantively alter the accuracy estimates. We did not identify publication status as a source of heterogeneity. For chest X-ray in suspected COVID-19 participants (3 studies, 1243 participants, 784 (63%) cases) the sensitivity ranged from 56.9% to 89.0% and specificity from 11.1% to 88.9%. The sensitivity and specificity of ultrasound of the lungs in suspected COVID-19 participants (1 study, 100 participants, 31 (31%) cases) were 96.8% and 62.3%, respectively. We could not perform a meta-analysis for chest X-ray or ultrasound due to the limited number of included studies. AUTHORS' CONCLUSIONS: Our findings indicate that chest CT is sensitive and moderately specific for the diagnosis of COVID-19 in suspected patients, meaning that CT may have limited capability in differentiating SARS-CoV-2 infection from other causes of respiratory illness. However, we are limited in our confidence in these results due to the poor study quality and the heterogeneity of included studies. Because of limited data, accuracy estimates of chest X-ray and ultrasound of the lungs for the diagnosis of suspected COVID-19 cases should be carefully interpreted. Future diagnostic accuracy studies should pre-define positive imaging findings, include direct comparisons of the various modalities of interest on the same participant population, and implement improved reporting practices. Planned updates of this review will aim to: increase precision around the accuracy estimates for chest CT (ideally with low risk of bias studies); obtain further data to inform accuracy of chest X-rays and ultrasound; and obtain data to further fulfil secondary objectives (e.g. 'threshold' effects, comparing accuracy estimates across different imaging modalities) to inform the utility of imaging along different diagnostic pathways.

Comparative Accuracy of Focused Cardiac Ultrasonography and Clinical Examination for Left Ventricular Dysfunction and Valvular Heart Disease: A Systematic Review and Meta-analysis.

Background: Incorporating focused cardiac ultrasonography (FoCUS) into clinical examination could improve the diagnostic yield of bedside patient evaluation. Purpose: To compare the accuracy of FoCUS-assisted clinical assessment versus clinical assessment alone for diagnosing left ventricular dysfunction or valvular disease in adults having cardiovascular evaluation. Data Sources: English-language searches of MEDLINE, Embase, and Web of Science from 1 January 1990 to 23 May 2019 and review of reference citations. Study Selection: Eligible studies were done in patients having cardiovascular evaluation; compared FoCUS-assisted clinical assessment versus clinical assessment alone for the diagnosis of left ventricular systolic dysfunction, aortic or mitral valve disease, or pericardial effusion; and used transthoracic echocardiography as the reference standard. Data Extraction: Three study investigators independently abstracted data and assessed study quality. Data Synthesis: Nine studies were included in the meta-analysis. The sensitivity of clinical assessment for diagnosing left ventricular dysfunction (left ventricular ejection fraction <50%) was 43% (95% CI, 33% to 54%), whereas that of FoCUS-assisted examination was 84% (CI, 74% to 91%). The specificity of clinical assessment was 81% (CI, 65% to 90%), and that of FoCUS-assisted examination was 89% (CI, 85% to 91%). The sensitivities of clinical assessment and FoCUS-assisted examination for diagnosing aortic or mitral valve disease (of at least moderate severity) were 46% (CI, 35% to 58%) and 71% (CI, 63% to 79%), respectively. Both the clinical assessment and the FoCUS-assisted examination had a specificity of 94% (CI, 91% to 96%). Limitation: Evidence was scant, persons doing ultrasonography had variable skill levels, and most studies had unclear or high risk of bias. Conclusion: Clinical examination assisted by FoCUS has greater sensitivity, but not greater specificity, than clinical assessment alone for identifying left ventricular dysfunction and aortic or mitral valve disease; FoCUS-assisted examination may help rule out cardiovascular pathology in some patients, but it may not be sufficient for definitive confirmation of cardiovascular disease suspected on physical examination. Primary Funding Source: None. (PROSPERO: CRD42019124318).

Publication Bias: Association of Diagnostic Accuracy in Radiology Conference Abstracts with Full-Text Publication.

Background Recent investigations have identified a faster time to publication for imaging studies with higher diagnostic test accuracy (DTA), but it is unknown whether such studies are more likely to be published. A higher probability of full-text publication for studies with higher DTA could have negative consequences on clinical decision making and patient care. Purpose To evaluate the proportion of imaging diagnostic accuracy studies presented as conference abstracts that reach full-text publication and to identify whether there is an association between diagnostic accuracy and full-text publication in peer-reviewed journals within 5 years after abstract submission. Materials and Methods Diagnostic accuracy research abstracts presented at the Radiological Society of North America (RSNA) Annual Meeting in 2011 and 2012 were evaluated between September 1, 2017, and January 11, 2018. Sensitivity and specificity from the abstracts were used to calculate the Youden index (sensitivity + specificity-1); additional abstract characteristics were extracted. To identify full-text publications within 5 years after abstract submission, PubMed and Google Scholar were searched, and authors were contacted. Logistic regression analysis was used to assess for associations between higher diagnostic accuracy and full-text publication. Results A total of 7970 abstracts were evaluated, and 405 were included. Of these, 288 (71%) reached full-text publication within 5 years after abstract submission. Logistic regression analysis accounting for several confounding variables failed to show an association between reported Youden index in the conference abstract and probability of full-text publication (odds ratio, 1.01; 95% confidence interval: 0.99, 1.02; P = .21). Conclusion More than a quarter of abstracts presented at the RSNA Annual Meeting do not reach full-text publication in peer-reviewed journals. The magnitude of reported diagnostic accuracy was not associated with full-text publication, which is consistent with results of diagnostic accuracy studies in other medical specialties. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Fielding in this issue.

Completeness of Reporting of Systematic Reviews of Diagnostic Test Accuracy Based on the PRISMA-DTA Reporting Guideline.

BACKGROUND: We evaluated the completeness of reporting of diagnostic test accuracy (DTA) systematic reviews using the recently developed Preferred Reporting Items for Systematic Reviews and MetaAnalyses (PRISMA)-DTA guidelines. METHODS: MEDLINE® was searched for DTA systematic reviews published October 2017 to January 2018. The search time span was modulated to reach the desired sample size of 100 systematic reviews. Reporting on a per-item basis using PRISMA-DTA was evaluated. RESULTS: One hundred reviews were included. Mean reported items were 18.6 of 26 (71%; SD = 1.9) for PRISMA-DTA and 5.5 of 11 (50%; SD = 1.2) for PRISMA-DTA for abstracts. Items in the results were frequently reported. Items related to protocol registration, characteristics of included studies, results synthesis, and definitions used in data extraction were infrequently reported. Infrequently reported items from PRISMA-DTA for abstracts included funding information, strengths and limitations, characteristics of included studies, and assessment of applicability. Reporting completeness was higher in higher impact factor journals (18.9 vs 18.1 items; P = 0.04), studies that cited PRISMA (18.9 vs 17.7 items; P = 0.003), or used supplementary material (19.1 vs 18.0 items; P = 0.004). Variability in reporting was associated with author country (P = 0.04) but not journal (P = 0.6), abstract word count limitations (P = 0.9), PRISMA adoption (P = 0.2), structured abstracts (P = 0.2), study design (P = 0.8), subspecialty area (P = 0.09), or index test (P = 0.5). Abstracts with a higher word count were more informative (R = 0.4; P < 0.001). No association with word counts was observed for full-text reports (R = -0.03; P = 0.06). CONCLUSIONS: Recently published reports of DTA systematic reviews are not fully informative when evaluated against the PRISMA-DTA guidelines. These results should guide knowledge translation strategies, including journal level (e.g., PRISMA-DTA adoption, increased abstract word count, and use of supplementary material) and author level (PRISMA-DTA citation awareness) strategies.

Best practices for MRI systematic reviews and meta-analyses.

As defined by the Cochrane Collaboration, a systematic review is a review of evidence with a clearly formulated question that uses systematic and explicit methods to identify, select, and critically appraise relevant primary research, and to extract and analyze data from the studies that are included in the review. Meta-analysis is a statistical method to combine the results from primary studies that accounts for sample size and variability to provide a summary measure of the studied outcome. Systematic reviews of diagnostic test accuracy present unique methodological and reporting challenges not present in systematic reviews of interventions. This review provides guidance and further resources highlighting current best practices in methodology and reporting of systematic reviews of diagnostic test accuracy, with a specific focus on challenges and opportunities for MRI imaging. Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018.

Citation bias in imaging research: are studies with higher diagnostic accuracy estimates cited more often?

OBJECTIVES: To assess the risk of citation bias in imaging diagnostic accuracy research by evaluating whether studies with higher accuracy estimates are cited more frequently than those with lower accuracy estimates. METHODS: We searched Medline for diagnostic accuracy meta-analyses published in imaging journals from January 2005 to April 2016. Primary studies from the meta-analyses were screened; those assessing the diagnostic accuracy of an imaging test and reporting sensitivity and specificity were eligible for inclusion. Studies not indexed in Web of Science, duplicates, and inaccessible articles were excluded. Topic (modality/subspecialty), study design, sample size, journal impact factor, publication date, times cited, sensitivity, and specificity were extracted for each study. Negative binomial regression was performed to evaluate the association of citation rate (times cited per month since publication) with Youden's index (sensitivity + specificity -1), highest sensitivity, and highest specificity, controlling for the potential confounding effects of modality, subspecialty, impact factor, study design, sample size, and source meta-analysis. RESULTS: There were 1016 primary studies included. A positive association between Youden's index and citation rate was present, with a regression coefficient of 0.33 (p = 0.016). The regression coefficient for sensitivity was 0.41 (p = 0.034), and for specificity, 0.32 (p = 0.15). CONCLUSION: A positive association exists between diagnostic accuracy estimates and citation rates, indicating that there is evidence of citation bias in imaging diagnostic accuracy literature. Overestimation of imaging test accuracy may contribute to patient harm from incorrect interpretation of test results. KEY POINTS: • Studies with higher accuracy estimates may be cited more frequently than those with lower accuracy estimates. • This citation bias could lead clinicians, reviews, and clinical practice guidelines to overestimate the accuracy of imaging tests, contributing to patient harm from incorrect interpretation of test results.