To determine if repeated intravenous exposures to gadolinium-based contrast agents (GBCAs) are associated with neuronal tissue deposition.
In this institutional review board-approved single-center ...study, signal intensities from T1-weighted magnetic resonance (MR) images and postmortem neuronal tissue samples from 13 patients who underwent at least four GBCA-enhanced brain MR examinations between 2000 and 2014 (contrast group) were compared with those from 10 patients who did not receive GBCA (control group). Antemortem consent was obtained from all study participants. Neuronal tissues from the dentate nuclei, pons, globus pallidus, and thalamus of these 23 deceased patients were harvested and analyzed with inductively coupled plasma mass spectrometry (ICP-MS), transmission electron microscopy, and light microscopy to quantify, localize, and assess the effects of gadolinium deposition. Associations between cumulative gadolinium dose, changes in T1-weighted MR signal intensity, and ICP-MS-derived tissue gadolinium concentrations were examined by using the Spearman rank correlation coefficient (ρ).
Compared with neuronal tissues of control patients, all of which demonstrated undetectable levels of gadolinium, neuronal tissues of patients from the contrast group contained 0.1-58.8 μg gadolinium per gram of tissue, in a significant dose-dependent relationship that correlated with signal intensity changes on precontrast T1-weighted MR images (ρ = 0.49-0.93). All patients in the contrast group had relatively normal renal function at the time of MR examination. Gadolinium deposition in the capillary endothelium and neural interstitium was observed only in the contrast group.
Intravenous GBCA exposure is associated with neuronal tissue deposition in the setting of relatively normal renal function. Additional studies are needed to investigate the clinical significance of these findings and the generalizability to other GBCAs. Online supplemental material is available for this article.
Introduction
Delayed aneurysm rupture and delayed intraparenchymal hemorrhages (DIPH) are poorly understood and often fatal complications of flow diversion (FD) for intracranial aneurysms. The ...purpose of this study was to identify risk factors for these complications.
Methods
We performed a systematic review on post-FD delayed aneurysm rupture and DIPH. For each reported case, we collected the following information: aneurysm location, size and rupture status, type of flow diverter used, timing of the hemorrhage, and neurological outcome. We reported descriptive statistics of patients suffering DIPH and delayed aneurysm rupture to determine if there were any characteristics consistently present among patients with these complications.
Results
We identified 81 delayed aneurysm ruptures and 101 DIPH. Of the delayed ruptures, 76.6 % (45/58) occurred within 1 month. The prognosis of delayed ruptures was poor, with 81.3 % (61/75) experiencing death or poor neurological outcome. Giant aneurysms accounted for 46.3 % of ruptures (31/67). Of these aneurysms, 80.9 % (55/68) were initially unruptured. Of the delayed ruptured aneurysms, 17.8 % (13/73) had prior or concomitant coiling. DIPHs were ipsilateral to the treated aneurysm in 82.2 % (60/73) of cases. Of the DIPH, 86.0 % (43/50) occurred within 1 month after FDS. Combined morbidity/mortality rate was 68.5 % (50/73) following DIPH. Of DIPHs, 23.0 % (14/61) occurred in patients with giant aneurysms.
Conclusions
Our study demonstrates that giant aneurysms represent almost 50 % of delayed aneurysm ruptures in the flow diverter literature. About 20 % of delayed ruptures occurred despite associated coiling. A substantial proportion of DIPHs occur early following FDS treatment of giant aneurysms.
Purpose To determine whether gadolinium deposits in neural tissues of patients with intracranial abnormalities following intravenous gadolinium-based contrast agent (GBCA) exposure might be related ...to blood-brain barrier integrity by studying adult patients with normal brain pathologic characteristics. Materials and Methods After obtaining antemortem consent and institutional review board approval, the authors compared postmortem neuronal tissue samples from five patients who had undergone four to 18 gadolinium-enhanced magnetic resonance (MR) examinations between 2005 and 2014 (contrast group) with samples from 10 gadolinium-naive patients who had undergone at least one MR examination during their lifetime (control group). All patients in the contrast group had received gadodiamide. Neuronal tissues from the dentate nuclei, pons, globus pallidus, and thalamus were harvested and analyzed with inductively coupled plasma mass spectrometry (ICP-MS), transmission electron microscopy with energy-dispersive x-ray spectroscopy, and light microscopy to quantify, localize, and assess the effects of gadolinium deposition. Results Tissues from the four neuroanatomic regions of gadodiamide-exposed patients contained 0.1-19.4 μg of gadolinium per gram of tissue in a statistically significant dose-dependent relationship (globus pallidus: ρ = 0.90, P = .04). In contradistinction, patients in the control group had undetectable levels of gadolinium with ICP-MS. All patients had normal brain pathologic characteristics at autopsy. Three patients in the contrast group had borderline renal function (estimated glomerular filtration rate <45 mL/min/1.73 m
) and hepatobiliary dysfunction at MR examination. Gadolinium deposition in the contrast group was localized to the capillary endothelium and neuronal interstitium and, in two cases, within the nucleus of the cell. Conclusion Gadolinium deposition in neural tissues after GBCA administration occurs in the absence of intracranial abnormalities that might affect the permeability of the blood-brain barrier. These findings challenge current understanding of the biodistribution of these contrast agents and their safety.
RSNA, 2017.
OBJECTIVE The authors performed a pooled analysis of 3 studies-IntrePED (International Retrospective Study of the Pipeline Embolization Device), PUFS (Pipeline for Uncoilable or Failed Aneurysms ...Study), and ASPIRe (Aneurysm Study of Pipeline in an Observational Registry)-in order to assess angiographic outcomes and clinical safety of the Pipeline embolization device (PED). METHODS IntrePED was a retrospective study, while PUFS and ASPIRe were prospective studies. For each patient included in these studies, the authors collected baseline demographic data, aneurysm characteristics, and procedural details. The primary outcomes for this combined analysis were clinical outcomes, including neurological morbidity and mortality and major ipsilateral intracranial hemorrhage and ischemic stroke. The secondary outcomes were angiographic occlusion rates, which were available for ASPIRe and PUFS only. RESULTS A total of 1092 patients with 1221 aneurysms were included across the 3 studies. The mean aneurysm size was 12.0 ± 7.8 mm and the mean neck size was 6.6 ± 4.8 mm. The major ipsilateral ischemic stroke rate was 3.7% (40/1091). The major ipsilateral intracranial hemorrhage rate was 2.0% (22/1091). The major neurological morbidity rate was 5.7% (62/1091). The neurological mortality rate was 3.3% (36/1091). The combined major morbidity and neurological mortality rate was 7.1% (78/1091). The complete occlusion rates were 75.0% at 180 days (111/148) and 85.5% at 1 year (94/110). The overall aneurysm retreatment rate was 3.0% (33/1091) at a mean follow-up time of 10.2 ± 10.8 months. CONCLUSIONS Endovascular treatment of intracranial aneurysms with the PED is safe and effective. Angiographic occlusion rates progressed with follow-up. Rates of stroke, hemorrhage, morbidity and mortality, and retreatment were low, especially given the fact that the aneurysms treated were generally large and wide necked.
Abstract
Flow diverters have drastically changed the landscape of intracranial aneurysm treatment and are now considered first-line therapy for select lesions. Their mechanism of action relies on ...intrinsic alteration in hemodynamic parameters, both at the parent artery and within the aneurysm sac. Moreover, the device struts act as a nidus for endothelial cell growth across the aneurysm neck ultimately leading to aneurysm exclusion from the circulation. In silico computational analyses and investigations in preclinical animal models have provided valuable insights into the underlying biological basis for flow diverter therapy. Here, we review the present understanding pertaining to flow diverter biology and mechanisms of action, focusing on stent design, induction of intra-aneurysmal thrombosis, endothelialization, and alterations in hemodynamics.
OBJECTIVE To identify and define clinical associations and radiologic findings of posterior reversible encephalopathy syndrome (PRES). PATIENTS AND METHODS Patients prospectively diagnosed as having ...PRES from October 1, 2005, through April 30, 2009, were pooled with retrospectively identified patients admitted from August 1, 1999, through September 30, 2005. We performed a detailed review of clinical information, including demographics, presenting symptoms, medical history, and risk factors. All patients underwent computed tomography of the brain or magnetic resonance imaging. Findings on magnetic resonance imaging were analyzed independently by 2 neuroradiologists. RESULTS We identified 120 cases of PRES in 113 patients (mean age, 48 years). Mean peak systolic blood pressure was 199 mm Hg (minimum-maximum, 160-268 mm Hg), and mean peak diastolic blood pressure was 109 mm Hg (minimum-maximum, 60-144 mm Hg). Etiologies of PRES included hypertension (n=69 61%), cytotoxic medications (n=21 19%), sepsis (n=8 7%), preeclampsia or eclampsia (n=7 6%), and multiple organ dysfunction (n=1 1%). Autoimmune disease was present in 51 patients (45%). Clinical presentations included seizures (n=84 74%), encephalopathy (n=32 28%), headache (n=29 26%), and visual disturbances (n=23 20%). In the 115 cases (109 patients) for which magnetic resonance imaging findings were available, the parieto-occipital regions were the most commonly involved (n=108 94%), followed by the frontal lobe (n=88 77%), temporal lobe (n=74 64%), and cerebellum (n=61 53%). Cerebellar involvement was significantly more frequent in patients with a history of autoimmunity ( P =.008), and patients with sepsis were more likely to have cortical involvement ( P <.001). CONCLUSION A substantial proportion of patients with PRES have underlying autoimmune conditions that may support endothelial dysfunction as a pathophysiologic mechanism. On brain imaging, the location and severity of vasogenic edema were mostly similar for the different clinical subgroups.
Open-access (OA) publishing is increasingly prevalent in dermatology, and many journals now offer hybrid options, including conventional (subscription-based access SA) publishing or OA (with an ...author publishing charge) in a subscription journal. OA publishing has been noted in many disciplines, but this has been rarely studied in dermatology.
Using the Clarivate Journal Citation Report, we compiled a list of English-language dermatology hybrid OA journals containing more than 5% OA articles. We sampled any OA review or original research article in 4 issues from 2018 to 2019 and matched an equal number of SA articles. Citation count, citation count excluding self-citations and view counts found using Scopus and Altmetrics score were recorded for each article. Statistical analyses were performed using logistic and negative binomial models using R software.
Twenty-seven hybrid dermatology journals were found, and 538 articles were sampled (269 OA, 269 SA). For both original research and review articles, OA articles had significantly higher mean citation counts (mean 13.2, standard deviation SD 17.0) compared to SA articles (mean 7.9, SD 8.8) (odds ratio OR 1.04; 95% CI 1.02-1.05; P < .001) including when adjusted for time from publication. Original research OA articles had significantly higher citation counts than original research SA articles (excluding self-citations; OR, 1.03; 95% CI, 1.01-1.05; P = .003), and review articles also had OA citation advantage than review SA articles (OR, 1.06; 95% CI, 1.02-1.11; P = .008). There was, however, no significant difference in citation counts between review articles and original research articles (OR, 1.00; 95% CI, 0.19-5.31; P = 1.000). There was no significant difference seen in view counts (OA: mean±SD 17.7±10.8; SA: mean±SD 17.1±12.4) and Altmetric score (OA: mean±SD 13.2±47.8; SA: mean±SD 6.3±25.0) between OA and SA articles. Potential confounders included the fact that more OA articles were published in Europe than in Asia, and pharmaceutical-funded articles were more likely to be published OA.
We noted a higher citation count for OA articles than SA articles in dermatology hybrid journals. However, dermatology researchers should take into account confounding factors when deciding whether to increase the impact of their work by selecting OA over SA publishing.
To examine the effect of changes in utilization and advances in cross-sectional imaging on radiologists' workload.
All computed tomography (CT) and magnetic resonance imaging (MRI) examinations ...performed at a single institution between 1999 and 2010 were identified and associated with the total number of images for each examination. Annual trends in institutional numbers of interpreted examinations and images were translated to changes in daily workload for the individual radiologist by normalizing to the number of dedicated daily CT and MRI work assignments, assuming a 255-day/8-hour work day schedule. Temporal changes in institutional and individual workload were assessed by Sen's slope analysis (Q = median slope) and Mann-Kendall test (Z = Z statistic).
From 1999 to 2010, a total of 1,517,149 cross-sectional imaging studies (CT = 994,471; MRI = 522,678) comprising 539,210,581 images (CT = 339,830,947; MRI = 199,379,634) were evaluated at our institution. Total annual cross-sectional studies steadily increased from 84,409 in 1999 to 147,336 in 2010, representing a twofold increase in workload (Q = 6465/year, Z = 4.2, P < .0001). Concomitantly, the number of annual departmental cross-sectional images interpreted increased from 9,294,140 in 1990 to 94,271,551 in 2010, representing a 10-fold increase (Q = 8707876/year, Z = 4.5, P < .0001). Adjusting for staffing changes, the number of images requiring interpretation per minute of every workday per staff radiologist increased from 2.9 in 1999 to 16.1 in 2010 (Q = 1.7/year, Z = 4.3, P < .0001).
Imaging volumes have grown at a disproportionate rate to imaging utilization increases at our institution. The average radiologist interpreting CT or MRI examinations must now interpret one image every 3-4 seconds in an 8-hour workday to meet workload demands.
Abstract
BACKGROUND: Early and mid-term safety and efficacy of aneurysm treatment with the Pipeline Embolization Device (PED) has been well demonstrated in prior studies.
OBJECTIVE: To present 5-yr ...follow-up for patients treated in the Pipeline for Uncoilable or Failed Aneurysms clinical trial.
METHODS: In our prospective, multicenter trial, 109 complex internal carotid artery (ICA) aneurysms in 107 subjects were treated with the PED. Patients were followed per a standardized protocol at 180 d and 1, 3, and 5 yr. Aneurysm occlusion, in-stent stenosis, modified Rankin Scale scores, and complications were recorded.
RESULTS: The primary endpoint of complete aneurysm occlusion at 180 d (73.6%) was previously reported. Aneurysm occlusion for those patients with angiographic follow-up progressively increased over time to 86.8% (79/91), 93.4% (71/76), and 95.2% (60/63) at 1, 3, and 5 yr, respectively. Six aneurysms (5.7%) were retreated. New serious device-related events at 1, 3, and 5 yr were noted in 1% (1/96), 3.5% (3/85), and 0% (0/81) of subjects. There were 4 (3.7%) reported deaths in our trial. Seventy-eight (96.3%) of 81 patients with 5-yr clinical follow-up had modified Rankin Scale scores ≤2. No delayed neurological deaths or hemorrhagic or ischemic cerebrovascular events were reported beyond 6 mo. No recanalization of a previously occluded aneurysm was observed.
CONCLUSION: Our 5-yr findings demonstrate that PED is a safe and effective treatment for large and giant wide-necked aneurysms of the intracranial ICA, with high rates of complete occlusion and low rates of delayed adverse events.
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