Rotational Vertebrobasilar Insufficiency: Is There a Physiological Spectrum? Phase-Contrast Magnetic Resonance Imaging Quantification in Healthy Volunteers.

BACKGROUND: Some cases of cerebral ischemia have been attributed to dynamic flow limitation in neck vessels. It however remains unknown whether this represents the extreme end of a physiological response. METHODS: Eighteen healthy volunteers were recruited to this prospective study. Cervical blood flow (ml/min/m2) was assessed using phase-contrast MRI, and cerebral perfusion ratios were assessed using arterial spin labeling perfusion at neutral position, predefined head rotations, as well as flexion and extension. Inter-reader agreements were assessed using intraclass correlation coefficient. RESULTS: The mean age was 38.6 ± 10.8 (range = 22-56) years, for five male participants and 13 females. The means for height and weight were 168 cm and 73.2 kg, respectively. There were no significant differences in individual arterial blood flow with change in head position (P > 0.05). Similarly, the repeated-measures analysis of variance test demonstrated no significant difference in perfusion ratios in relation to head position movement (P > 0.05). Inter-reader agreement was excellent (intraclass correlation coefficient = 0.97). CONCLUSIONS: There is neither significant change in either individual cervical arterial blood flow nor cerebral perfusion within the normal physiological/anatomical range of motion in healthy individuals. It is therefore reasonable to conclude that any such hemodynamic change identified in a patient with ischemic stroke be considered causative.

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.

Long Vascular Sheaths for Transfemoral Neuroendovascular Procedures in Children.

PURPOSE: To evaluate the safety and efficacy of long vascular sheaths for transfemoral neuroendovascular procedures in children. MATERIALS AND METHODS: A retrospective evaluation of transfemoral neuroendovascular procedures in children <18 years, using long sheaths was undertaken analyzing procedure type, fluoroscopic times, technical success, access site and systemic complications. Twenty-seven consecutive procedures were included over a 2-year period. Mean age was 8.4 years (standard deviation [SD] 6.3) (range 17.0 months-16.3 years). RESULTS: Patients were 44% female and mean weight was 35.0 kg (SD 22.8) (range 9.8-72.2 kg). A third of the procedures were performed in ≤15 kg children. The most common procedure was for embolization (n=13, 48.1%) and the most common indication was dual microcatheter technique (52%). The most common device used was the 5 Fr Cook Shuttle sheath. Mean fluoroscopy time was 61.9 minutes (SD 43.1). Of these procedures, 93% were technically successful. Femoral vasospasm, when present, was self-limiting. Complications (3/27, 11.1%) included groin hematoma (n=1), neck vessel spasm that resolved with verapamil (n=1), and intracranial thromboembolism (n=1), with no significant difference between the ≤15 kg and >15 kg subcohorts. There were no aorto-femoro-iliac or limb-ischemic complications. CONCLUSION: Long vascular sheaths without short femoral sheaths can be safely used for pediatric neuroendovascular procedures as they effectively increase inner diameter access without increasing the outer sheath diameter. This property increases the range of devices used and intracranial techniques that can be safely performed without arterial compromise, thus increasing the repertoire of the neurointerventionist.

Use of radial access sheaths for transfemoral neuroendovascular procedures in children.

PURPOSE: Pediatric neuroendovascular procedures require special considerations. Given small vessel sizes, risk for arterial injury must be weighed against use of larger devices, with the diameter of the sheath being a known association with arterial complications. We recently transitioned to using thin-walled radial sheaths for transfemoral angiography in children, given their lower profile. Here, we report on these sheaths' technical success and complications, comparing against a historical cohort where regular vascular sheaths were employed. METHODS: We retrospectively recorded patient and procedural data from 168 consecutive procedures from September 2017 to January 2019 when radial-specific sheaths were exclusively used at our tertiary pediatric hospital. These results were compared to data from September 2015 to January 2017, when regular vascular sheaths were exclusively used in 152 consecutive procedures. Statistical analysis was performed using unpaired t test or chi-square test, with p < 0.05 considered statistically significant. RESULTS: Patient characteristics (age, sex, weight) were not statistically different between the case and control group. No significant differences were found in the procedural data with the exception of heparin use which was higher in the radial-sheath cohort. There was a decrease in the rate of complications in the case group (1.2%) versus control group (2.6%), though not statistically different. CONCLUSION: Radial-specific sheaths have numerous beneficial characteristics that make them well-suited to the pediatric population. In our study, we show that radial sheaths are equally effective and safe perioperatively. Follow-up research may show if radial sheaths used transfemorally decrease long-term complications such as limb-length discrepancy and mortality.

Can Children Be Considered for Transradial Interventions?: Prospective Study of Sonographic Radial Artery Diameters.

BACKGROUND: Transradial intervention is increasingly replacing approaches, due to lower access complications, cost, and improved patient satisfaction. There are limited supporting data in the pediatric literature, largely due to concerns regarding arterial size. The objective of this study was to measure radial artery diameters in children across all age groups, to establish reference ranges for clinical use. METHODS: This prospective study was carried out in children ≤18 years of age who underwent ultrasound for measuring radial artery diameters from November 2018 to November 2019. The cohort was divided into age groups: ≤2, 3 to 5, 6 to 8, 9 to 11, 12 to 14, 15 to 18 years, and into pre- and post-adolescent (≥12 years) groups. RESULTS: One hundred thirty-four children (M:F=63:71) were included, with bilateral measurements resulting in 268 data points. Mean age was 8.9±5.8 years (range, 29 days to 18 years), mean weight 37.2±27.5 kg (range, 1.7-149.1 kg). Mean-corrected radial artery diameter was 1.86±0.44 mm. There was no difference in arterial diameters between males and females (1.90±0.50 versus 1.81±0.53 mm; P=0.73) or between right and left sides (1.87±0.46 versus 1.87±0.47, P=0.98). There was a strong correlation of diameter with age (R=0.75; P<0.00001) and weight (R=0.74; P<0.00001). There was linear increase in arterial growth rates in early childhood, followed by plateauing to adult sizes in adolescents. Inter-reader agreement was 0.95. CONCLUSIONS: We provide a reference range for radial artery diameters across childhood ages, which can be used for decision-making. This could be the basis for designing a trial of transradial intervention in children, to establish clinical safety and efficacy.