| 1. |
- Almqvist, Hakan, et al.
(författare)
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Radiological evaluation in patients with clinical suspicion of cerebral venous sinus thrombosis presenting with nontraumatic headache-a retrospective observational study with a validation cohort
- 2020
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Ingår i: BMC Medical Imaging. - : BMC. - 1471-2342. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Clinical suspicion of cerebral venous sinus thrombosis (CVST) is imprecise due to non-specific symptoms such as headache. The aim was to retrospectively assess the diagnostic value of nonenhanced CT (neCT) in patients with nontraumatic headache and clinically suspected CVST. Methods A retrospective consecutive series of patients referred 2013-2015 for radiology were evaluated. Eligible patients had nontraumatic headache and suspicion of CVST stated in the referral, investigated with CT venography (CTV) and nonenhanced CT (neCT). neCT scans were re-evaluated for the presence of CVST or other pathology. All CTVs were checked for the presence of CVST. The validation cohort consisted of 10 patients with nontraumatic CVT (2017-2019). Results Less than 1% (1/104) had a suspected thrombus on neCT, confirmed by subsequent CTV. The remaining 99% had a CTV excluding CVST. Eleven percent had other imaging findings explaining their symptoms. In the patient with CVST, the thrombosed dural sinus was high attenuating (maximum HU 89) leading to the suspicion of CVST confirmed by CTV. The validation cohort (n = 10) confirmed the presence of a high attenuating (HU > 65) venous structure in the presence of a confirmed thrombus in all patients presenting within 10 days (suspicion written in referral, 10%). Conclusions Despite clinical suspicion, imaging findings of CVST in nontraumatic headache are uncommon. Evaluating neCT for high attenuation in dural sinuses, followed by CTV for confirmation in selected cases seems reasonable. CVST should be recognized by all radiologists and requires a high level of awareness when reading neCT for other indications.
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| 2. |
- Delgado, Anna Falk, et al.
(författare)
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Discrimination between primary low-grade and high-grade glioma with 11C-methionine PET : a bivariate diagnostic test accuracy meta-analysis
- 2018
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Ingår i: British Journal of Radiology. - : British Institute of Radiology. - 0007-1285 .- 1748-880X. ; 91:1082
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Forskningsöversikt (refereegranskat)abstract
- Objective: To perform a meta-analysis evaluating the diagnostic accuracy of 11C-methionine (MET) positron emission tomography (PET) to discriminate between primary low-grade glioma (LGG) and high-grade glioma (HGG).Methods: A systematic database search was performed by a librarian in relevant databases with the latest search on 07 November 2016. Hits were assessed for inclusion independently by two authors. Individual patient data on relative MET uptake was extracted on patients examined pre-operatively with MET PET and subsequent neuropathological diagnosis of astrocytoma or oligodendroglioma. Individual patient data were analysed for diagnostic accuracy using a bivariate diagnostic random-effects meta-analysis model with restricted maximum likelihood estimation method. Bivariate meta-regression and subgroup analyses assessed study heterogeneity and validity. This study is registered with PROSPERO, number CRD42016050747.Results: Out of 1828 hits, 13 studies comprising of 241 individuals were included in the quantitative and qualitative analysis. MET PET had an area under the bivariate summary receiver operating characteristics curve of 0.78 to discriminate between LGG and HGG and a summary sensitivity of 0.80 with 95% confidence interval (CI) (0.66–0.88) and a summary false positive rate of 0.28, 95% CI (0.19–0.38). Heterogeneity was described by; bias in patient inclusion, study quality, and ratio method. Optimal cutoff for relative MET uptake was 2.21.Conclusion: MET PET had a moderately high diagnostic accuracy for the discrimination between primary LGG and HGG.Advances in knowledge: MET PET can be used as a clinical tool for the non-invasive discrimination between LGG and HGG with a moderately high accuracy at cut-off 2.21.
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| 3. |
- Delgado, Anna Falk, et al.
(författare)
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Glioma Grade Discrimination with MR Diffusion Kurtosis Imaging : A Meta-Analysis of Diagnostic Accuracy
- 2018
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Ingår i: Radiology. - : RADIOLOGICAL SOC NORTH AMERICA. - 0033-8419 .- 1527-1315. ; 287:1, s. 119-127
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To assess the diagnostic test accuracy and sources of heterogeneity for the discriminative potential of diffusion kurtosis imaging (DKI) to differentiate low-grade glioma (LGG) (World Health Organization [WHO] grade II) from high-grade glioma (HGG) (WHO grade III or IV).Materials and Methods: The Cochrane Library, Embase, Medline, and the Web of Science Core Collection were systematically searched by two librarians. Retrieved hits were screened for inclusion and were evaluated with the revised tool for quality assessment for diagnostic accuracy studies (commonly known as QUADAS-2) by two researchers. Statistical analysis comprised a random-effects model with associated heterogeneity analysis for mean differences in mean kurtosis (MK) in patients with LGG or HGG. A bivariate restricted maximum likelihood estimation method was used to describe the summary receiver operating characteristics curve and bivariate meta-regression.Results: Ten studies involving 430 patients were included. The mean difference in MK between LGG and HGG was 0.17 (95% confidence interval [CI]: 0.11, 0.22) with a z score equal to 5.86 (P<.001). The statistical heterogeneity was explained by glioma subtype, echo time, and the proportion of recurrent glioma versus primary glioma. The pooled area under the curve was 0.94 for discrimination of HGG from LGG, with 0.85 (95% CI: 0.74, 0.92) sensitivity and 0.92 (95% CI: 0.81, 0.96) specificity. Heterogeneity was driven by neuropathologic subtype and DKI technique.Conclusion: MK shows high diagnostic accuracy in the discrimination of LGG from HGG.
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| 4. |
- Delgado, Anna Falk, et al.
(författare)
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Neuroimaging lesion assessment by pseudo-subtraction of overlaid semi-transparent volumes : A technical description and feasibility series
- 2021
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Ingår i: The Neuroradiology Journal. - : Sage Publications. - 1971-4009 .- 2385-1996. ; 34:2, s. 128-130
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Tidskriftsartikel (refereegranskat)abstract
- Assessing and reporting clinical images constitutes the mainstay of clinical neuroradiology. Continually increasing numbers of neuroradiology referrals and follow-up examinations call for reproducible, accurate, and rapid workflows. Readily available and easy to use, advanced workstation tools such as co-registration of volume series can be used to overlay volume series from two different time points as semi-transparent images, with an inverse color scale. By overlaying semi-transparent inverse color maps, stationary findings will be shaded out in grey, whereas progressing or regressing lesions will be highlighted as white or black in the resulting pseudo-subtraction map. Pseudosubtraction in longitudinal neuroradiology imaging might enhance workflow and imaging assessment.
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| 5. |
- Falk Delgado, Alberto, et al.
(författare)
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Arterial spin labeling MR imaging for differentiation between high- and low-grade glioma - A meta-analysis
- 2018
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Ingår i: Neuro-Oncology. - : Oxford University Press (OUP). - 1522-8517 .- 1523-5866. ; 20:11, s. 1450-1461
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Tidskriftsartikel (refereegranskat)abstract
- Background. Arterial spin labeling is an MR imaging technique that measures cerebral blood flow (CBF) noninvasively. The aim of the study is to assess the diagnostic performance of arterial spin labeling (ASL) MR imaging for differentiation between high-grade glioma and low-grade glioma. Methods. Cochrane Library, Embase, Medline, and Web of Science Core Collection were searched. Study selection ended November 2017. This study was prospectively registered in PROSPERO (CRD42017080885). Two authors screened all titles and abstracts for possible inclusion. Data were extracted independently by 2 authors. Bivariate random effects meta-analysis was used to describe summary receiver operating characteristics. Trial sequential analysis (TSA) was performed. Results. In total, 15 studies with 505 patients were included. The diagnostic performance of ASL CBF for glioma grading was 0.90 with summary sensitivity 0.89 (0.79-0.90) and specificity 0.80 (0.72-0.89). The diagnostic performance was similar between pulsed ASL (AUC 0.90) with a sensitivity 0.85 (0.71-0.91) and specificity 0.83 (0.69- 0.92) and pseudocontinuous ASL (AUC 0.88) with a sensitivity 0.86 (0.79-0.91) and specificity 0.80 (0.65-0.87). In astrocytomas, the diagnostic performance was 0.89 with sensitivity 0.86 (0.79 to 0.91) and specificity 0.79 (0.63 to 0.89). Sensitivity analysis confirmed the robustness of the findings. TSA revealed that the meta-analysis was adequately powered. Conclusion. Arterial spin labeling MR imaging had an excellent diagnostic accuracy for differentiation between high-grade and low-grade glioma. Given its low cost, non-invasiveness, and efficacy, ASL MR imaging should be considered for implementation in the routine workup of patients with glioma.
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| 6. |
- Falk Delgado, Alberto, et al.
(författare)
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Clinical outcome after surgical clipping or endovascular coiling for cerebral aneurysms : a pragmatic meta- analysis of randomized and non- randomized trials with short- and long- term follow- up
- 2017
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Ingår i: JOURNAL OF NEUROINTERVENTIONAL SURGERY. - : BMJ PUBLISHING GROUP. - 1759-8478 .- 1759-8486. ; 9:3, s. 264-
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Tidskriftsartikel (refereegranskat)abstract
- Background Two randomized trials have evaluated clipping and coiling in patients with ruptured aneurysms. Aggregated evidence for management of ruptured and unruptured aneurysms is missing. Objective To conduct a meta- analysis evaluating clinical outcome after aneurysm treatment. Methods PubMed, Cochrane Central Register of Controlled Trials, and Clinicaltrials. gov were searched for studies evaluating aneurysm treatment. The primary outcome measure was an independent clinical outcome ( modified Rankin scale 0- 2, Glasgow Outcome Scale 4- 5, or equivalent). Secondary outcomes were poor outcome and mortality. ORs were calculated on an intention- to- treat basis with 95% Cls. Outcome heterogeneity was evaluated with Cochrane's Q test ( significance level cut- off value at < 0.10) and l(2) ( significance cut- off value > 50%) with the Mantel-Haenszel method for dichotomous outcomes. A p value < 0.05 was regarded as statistically significant. Results Searches yielded 18 802 articles. All titles were assessed, 403 abstracts were evaluated, and 183 full-text articles were read. One- hundred and fifty articles were qualitatively assessed and 85 articles were included in the meta- analysis. Patients treated with coiling ( randomized controlled trials ( RCTs)) had higher independent outcome at short- term follow- up ( OR= 0.67, 95% Cl 0.57 to 0.79). Independent outcome was favored for coiling at intermediate and long- term follow-up ( RCTs and observational studies combined-OR= 0.80, 0.68 to 0.94 and OR= 0.81, 0.71 to 0.93, respectively). Independent outcome and lower mortality was favored after coiling in unruptured aneurysms ( database registry studies) at short- term follow- up ( OR= 0.34, 0.29 to 0.41 and OR= 1.74, 1.52 to 1.98, respectively). Conclusions This meta- analysis evaluating clinical outcome after coiling or clipping for intracranial aneurysms, indicates a higher independent outcome and lower mortality after coiling.
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| 7. |
- Falk Delgado, Alberto, et al.
(författare)
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Complete Lymph Node Dissection in Melanoma : A Systematic Review and Meta-Analysis
- 2017
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Ingår i: Anticancer Research. - : Anticancer Research USA Inc.. - 0250-7005 .- 1791-7530. ; 37:12, s. 6825-6829
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Forskningsöversikt (refereegranskat)abstract
- Background: The aim of this meta-analysis was to estimate the survival after immediate complete lymph node dissection (CLND) compared to observation only (OO) or delayed CLND in patients with melanoma and lymph node metastasis.Materials and Methods: A systematic search was performed in: PubMed, Web of Science, Cochrane Library, CINAHL, Clinical trials and Embase. Eligible studies were randomized controlled trials (RCTs) comparing: CLND with OO, or immediate CLND with delayed CLND.Results: Four RCTs were included. There was no difference in melanoma-specific survival (MSS) (HR=0.91, 95% CI=0.77-1.08, p=0.29). In a sensitivity analysis, MSS was higher after immediate CLND compared to delayed CLND in patients with nodal metastasis (HR=0.63, 95% CI=0.35-0.74, p=0.0004) without evidence of heterogeneity.Conclusion: CLND appears to have no additional survival benefit after SNB compared to OO. However, subgroup analysis suggests a time-dependent benefit for early surgical lymph node removal compared to delayed or none.
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| 8. |
- Falk Delgado, Anna, et al.
(författare)
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Diagnostic value of alternative techniques to gadolinium-based contrast agents in MR neuroimaging : a comprehensive overview
- 2019
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Ingår i: Insights into Imaging. - : Springer Science and Business Media LLC. - 1869-4101. ; 10:1
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Forskningsöversikt (refereegranskat)abstract
- Gadolinium-based contrast agents (GBCAs) increase lesion detection and improve disease characterization for many cerebral pathologies investigated with MRI. These agents, introduced in the late 1980s, are in wide use today. However, some non-ionic linear GBCAs have been associated with the development of nephrogenic systemic fibrosis in patients with kidney failure. Gadolinium deposition has also been found in deep brain structures, although it is of unclear clinical relevance. Hence, new guidelines from the International Society for Magnetic Resonance in Medicine advocate cautious use of GBCA in clinical and research practice. Some linear GBCAs were restricted from use by the European Medicines Agency (EMA) in 2017.This review focuses on non-contrast-enhanced MRI techniques that can serve as alternatives for the use of GBCAs. Clinical studies on the diagnostic performance of non-contrast-enhanced as well as contrast-enhanced MRI methods, both well established and newly proposed, were included. Advantages and disadvantages together with the diagnostic performance of each method are detailed. Non-contrast-enhanced MRIs discussed in this review are arterial spin labeling (ASL), time of flight (TOF), phase contrast (PC), diffusion-weighted imaging (DWI), magnetic resonance spectroscopy (MRS), susceptibility weighted imaging (SWI), and amide proton transfer (APT) imaging.Ten common diseases were identified for which studies reported comparisons of non-contrast-enhanced and contrast-enhanced MRI. These specific diseases include primary brain tumors, metastases, abscess, multiple sclerosis, and vascular conditions such as aneurysm, arteriovenous malformation, arteriovenous fistula, intracranial carotid artery occlusive disease, hemorrhagic, and ischemic stroke.In general, non-contrast-enhanced techniques showed comparable diagnostic performance to contrast-enhanced MRI for specific diagnostic questions. However, some diagnoses still require contrast-enhanced imaging for a complete examination.
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| 9. |
- Falk Delgado, Alberto, et al.
(författare)
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Home institution bias in the New England Journal of Medicine? : A noninferiority study on citation rates
- 2018
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Ingår i: Scientometrics. - : SPRINGER. - 0138-9130 .- 1588-2861. ; 115:1, s. 607-611
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Tidskriftsartikel (refereegranskat)abstract
- Recently, in the four top journals of humanities, an institutional bias towards publication of authors from Harvard and Yale was shown. The New England Journal of Medicine (NEJM) is today the highest ranked general medical journal. It is unknown if there exists institutional bias favoring publication of articles originating from Harvard University, since the NEJM is produced by the Massachusetts Medical Society with close connections to the Harvard University. We examined if studies originating from the Harvard University published in the NEJM were noninferior in terms of citation rates compared to articles with an origin outside Harvard University. We evaluated original research articles published in the NEJM in 2000 up until June 2001. A two-sample noninferiority test based on the primary endpoint of citations was performed. Twenty-two studies were affiliated to the Harvard University and 280 studies were not affiliated to the Harvard University. The mean number of citations for Harvard affiliated studies was 625 (95% CI 358-952, median 354) and for non-Harvard affiliated studies 493 (95% CI 421-569, median 303). The mean difference was not statistically different between affiliations, but fulfilled the requirements for noninferiority [132 (95% CI - 138-402, P = 0.343), Delta 200]. In summary, citation rates were comparable between studies origination from the Harvard University compared to non-Harvard Institutions. Based on these results there appears to be low risk of institutional bias in the publishing process of original studies in the NEJM.
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| 10. |
- Falk-Delgado, Anna, et al.
(författare)
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Improved clinical outcome 3 months after endovascular treatment, including thrombectomy, in patients with acute ischemic stroke : a meta-analysis
- 2016
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Ingår i: Journal of neurointerventional surgery. - : BMJ. - 1759-8486 .- 1759-8478. ; 8:7
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Intravenous thrombolysis with tissue plasminogen activator is standard treatment in acute stroke today. The benefit of endovascular treatment has been questioned. Recently, studies evaluating endovascular treatment and intravenous thrombolysis compared with intravenous thrombolysis alone, have reported improved outcome for the intervention group. The aim of this study was to perform a meta-analysis of randomized controlled trials comparing endovascular treatment in addition to intravenous thrombolysis with intravenous thrombolysis alone.METHODS: Databases were searched for eligible randomized controlled trials. The primary outcome was a functional neurological outcome after 90 days. A secondary outcome was severe disability and death. Data were pooled in the control and intervention groups, and OR was calculated on an intention to treat basis with 95% CIs. Outcome heterogeneity was evaluated with Cochrane's Q test (significance level cut-off value at <0.10) and I(2) (significance cut-off value >50%) with the Mantel-Haenszel method for dichotomous outcomes. A p value <0.05 was regarded as statistically significant.RESULTS: Six studies met the eligibility criteria, and data from 1569 patients were analyzed. A higher probability of a functional neurological outcome after 90 days was found for the intervention group (OR 2, 95% CI 2 to 3). There was a significantly higher probability of death and severe disability in the control group compared with the intervention group.CONCLUSIONS: Endovascular treatment in addition to intravenous thrombolysis for acute ischemic stroke leads to an improved clinical outcome after 3 months, compared with patients receiving intravenous thrombolysis alone.
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