The blood–brain barrier (BBB) is essential for normal function of the brain, and its role in many brain pathologies has been the focus of numerous studies during the last decades. Dysfunction of the ...BBB is not only being shown in numerous brain diseases, but animal studies have indicated that it plays a direct key role in the genesis of neurovascular dysfunction and associated neurodegeneration. As such evidence accumulates, the need for robust and clinically applicable methods for minimally invasive assessment of BBB integrity is becoming urgent. This review provides an introduction to BBB imaging methods in the clinical scenario. First, imaging modalities are reviewed, with a focus on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). We then proceed to review image analysis methods, including quantitative and semi-quantitative methods. The advantages and limitations of each approach are discussed, and future directions and questions are highlighted.
We report the case of a 2-year-old Bedouin boy in whom developed severe and unusual complications after being stung, most probably, by the yellow scorpion Leiurus quinquestriatus hebraeus. Five hours ...after arrival to the emergency department, the boy had multisystem organ failure involving the central nervous system (seizure activity followed by coma with dilated, nonreactive pupils, and severe brain edema), shock (noncardiogenic), disseminated intravascular coagulation, renal failure, hepatic failure, and watery diarrhea, causing his death. In view of the relevant literature, we discuss the pathophysiologic events ultimately leading to his death.
Abstract This case report describes a twin fetus diagnosed in the third trimester with an enlarging abdominal mass that was confirmed on fetal magnetic resonance imaging (MRI) to be a hepatic ...mesenchymal hamartoma (HMH) without involvement of the placenta. Serial ultrasonography demonstrated progressive enlargement of the mass and infant was delivered at 33 + 6 weeks gestational age following maternal complications. On the fifth day, at laparotomy, a huge mass connected to the lower portion of the liver was completely resected. Microscopic evaluation confirmed a hepatic mesenchymal hamartoma. Postoperative recovery was uneventful and the infant was discharged at 4 weeks. The antenatal diagnosis of the hepatic mesenchymal hamartoma by fetal MRI and subsequent follow-up by serial ultrasonography emphasizes the importance of combining these 2 modalities for optimal management of the pregnancy to allow a favorable outcome.
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•A Mediterranean and low carbohydrate diet decreases hepatic fat more than a low-fat diet, beyond visceral fat changes.•Decreases in hepatic fat are independently associated with ...specific improved parameters.•The beneficial effect of a Mediterranean diet over a low-fat diet is mainly mediated by decreases in hepatic fat.
It is unclear if a reduction in hepatic fat content (HFC) is a major mediator of the cardiometabolic benefit of lifestyle intervention, and whether it has prognostic significance beyond the loss of visceral adipose tissue (VAT). In the present sub-study, we hypothesized that HFC loss in response to dietary interventions induces specific beneficial effects independently of VAT changes.
In an 18-month weight-loss trial, 278 participants with abdominal obesity/dyslipidemia were randomized to low-fat (LF) or Mediterranean/low-carbohydrate (MED/LC + 28 g walnuts/day) diets with/without moderate physical activity. HFC and abdominal fat-depots were measured using magnetic resonance imaging at baseline, after 6 (sub-study, n = 158) and 18 months.
Of 278 participants (mean HFC 10.2% range: 0.01%–50.4%), the retention rate was 86.3%. The %HFC substantially decreased after 6 months (−6.6% absolute units −41% relatively) and 18 months (−4.0% absolute units −29% relatively; p <0.001 vs. baseline). Reductions of HFC were associated with decreases in VAT beyond weight loss. After controlling for VAT loss, decreased %HFC remained independently associated with reductions in serum gamma glutamyltransferase and alanine aminotransferase, circulating chemerin, and glycated hemoglobin (p <0.05). While the reduction in HFC was similar between physical activity groups, MED/LC induced a greater %HFC decrease (p = 0.036) and greater improvements in cardiometabolic risk parameters (p <0.05) than the LF diet, even after controlling for VAT changes. Yet, the greater improvements in cardiometabolic risk parameters induced by MED/LC were all markedly attenuated when controlling for HFC changes.
%HFC is substantially reduced by diet-induced moderate weight loss and is more effectively reduced by the MED/LC diet than the LF diet, independently of VAT changes. The beneficial effects of the MED/LC diet on specific cardiometabolic parameters appear to be mediated more by decreases in %HFC than VAT loss.
High hepatic fat content is associated with metabolic syndrome, type 2 diabetes mellitus, and coronary heart disease. In the CENTRAL 18-month intervention trial, a Mediterranean/low-carbohydrate diet induced a greater decrease in hepatic fat content than a low-fat diet, conferring beneficial health effects that were beyond the favorable effects of visceral fat loss.
ClinicalTrials.gov Identifier: NCT01530724.
We present a case of a 51-year-old man who was injured in a bicycle accident. His main injury was an unstable fracture of the cervical and thoracic vertebral column. Several hours after his arrival ...to the hospital the patient underwent open reduction and internal fixation (ORIF) of the cervical and thoracic spine. The patient was hospitalized in our critical care unit for 99 days. During this time patient had several episodes of severe bradycardia and asystole; some were short with spontaneous return to sinus and some required pharmacological treatment and even Cardiopulmonary Resuscitation (CPR). Initially, these episodes were attributed to the high cervical spine injury, but, later on, CT scan suggested that a fixation screw abutted on the esophagus and activated the vagus nerve by direct pressure. After repositioning of the cervical fixation, the bradycardia and asystole episodes were no longer observed and the patient was released to a rehabilitation ward. This case is presented in order to alert practitioners to the possibility that, after operative fixation of cervical spine injuries, recurrent episodes of bradyarrhythmia can be caused by incorrect placement of the fixation screws and might be confused with the natural history of the high cervical cord injury.
Background
Magnetic resonance imaging has been recognized for years as the safest and most precise imaging method, particularly for children. The accuracy of MRI depends on avoidance of patient ...movement during the study. This may be difficult for children and may require anesthesia.
Objective
We evaluated an introductory instruction program as an assistive tool in performing MRI without anesthesia.
Materials and methods
In one institution, 121 children were randomized to undergo full interactive pre-MRI instruction (
n
=64), which included an instructional booklet, movie and simulator practice, or partial instruction (
n
=57), comprised of the booklet only. All researchers and health care professionals involved, except for the one who instructed the families, were masked to the group allocation. Parents’ anxiety, according to the Spielberger state anxiety inventory, was measured.
Results
Median age was 7.4 years (range: 5 years–16 years). Anesthesia was required for fewer children who received full compared to partial instruction: 17 (27%) vs. 27 (47%),
P
≤0.02. The median anxiety level prior to instruction was higher than the median level after instruction, for both the partial and full instruction groups.
Conclusion
Instruction including simulator practice was associated with a decreased need for anesthesia among children undergoing MRI scans.
Background
Idiopathic intracranial hypertension (IIH) is characterized by elevated intracranial pressure without a clear cause.
Purpose
To investigate dynamic imaging findings in IIH and their ...relation to mechanisms underlying intracranial pressure normalization.
Study Type
Prospective.
Population
Eighteen IIH patients and 30 healthy controls.
Field Strength/Sequence
T1‐weighted, venography, fluid attenuation inversion recovery, and apparent diffusion coefficients were acquired on 1.5T scanner.
Assessment
The dural sinus was measured before and after lumbar puncture (LP). The degree of sinus occlusion was evaluated, based on 95% confidence intervals of controls. We studied a number of neuroimaging biomarkers associated with IIH (sinus occlusion; optic nerve; distribution of cerebrospinal fluid into the subarachnoid space, sulci and lateral ventricles (LVs); Meckel's caves; arachnoid granulation; pituitary and choroid plexus), before and after LP, using a set of specially developed quantification techniques.
Statistical Tests
Relationships among various biomarkers were investigated (Pearson correlation coefficient) and linked to long‐term disease outcomes (logistic regression). The t‐test and the Wilcoxon rank test were used to compare between controls and before and after LP data.
Results
As a result of LP, the following were found to be in good accordance with the opening pressure: relative compression of cerebrospinal fluid (R = –0.857, P < 0.001) and brain volumes (R = –0.576, P = 0.012), LV expansion (R = 0.772, P < 0.001) and venous volume (R = 0.696, P = 0.001), enlargement of the pituitary (R = 0.640, P = 0.023), and shrinkage of subarachnoid space (R = –0.887, P < 0.001). The only parameter that had an impact on long‐term prognosis was cross‐sectional size of supplemental drainage veins after LP (sensitivity of 92%, specificity of 20%, and area under the curve of 0.845, P < 0.001).
Data Conclusion
We present an approach for quantitative characterization of the intracranial venous system and its implementation as a diagnostic assistance tool. We conclude that formation of supplementary drainage veins might serve as a long‐lasting compensatory mechanism.
Level of Evidence: 2
Technical Efficacy: Stage 3
J. Magn. Reson. Imaging 2018;47:913–927.
Patient-specific QCT-based finite element (QCTFE) analyses enable highly accurate quantification of bone strength. We evaluated CT scanner influence on QCTFE models of long bones.
A femur, humerus, ...and proximal femur without the head were scanned with K2HPO4 phantoms by seven CT scanners (four models) using typical clinical protocols. QCTFE models were constructed. The geometrical dimensions, as well as the QCT-values expressed in Hounsfield unit (HU) distribution was compared. Principal strains at representative regions of interest (ROIs), and maximum principal strains (associated with fracture risk) were compared. Intraclass correlation coefficients (ICCs) were calculated to evaluate strain prediction reliability for different scanners. Repeatability was examined by scanning the femur twice and comparing resulting QCTFE models.
Maximum difference in geometry was 2.3%. HU histograms before phantom calibration showed wide variation between QCT scans; however, bone density histogram variability was reduced after calibration and algorithmic manipulation. Relative standard deviation (RSD) in principal strains at ROIs was <10.7%. ICC estimates between scanners were >0.9. Fracture-associated strain had 6.7%, 8.1%, and 13.3% maximum RSD for the femur, humerus, and proximal femur, respectively. The difference in maximum strain location was <2 mm. The average difference with repeat scans was 2.7%.
Quantification of strain differences showed mean RSD bounded by ∼6% in ROIs. Fracture-associated strains in “regular” bones showed a mean RSD bounded by ∼8%. Strains were obtained within a ±10% difference relative to the mean; thus, in a longitudinal study only changes larger than 20% in the principal strains may be significant. ICCs indicated high reliability of QCTFE models derived from different scanners.
Post-stroke depression (PSD) is a common and serious complication following stroke. Both stroke and depression have independently been associated with pathologically elevated glutamate levels in the ...brain's extra-cerebral fluid (ECF). Here we evaluate an alternative therapeutic approach to PSD with pyruvate. Rats were randomly assigned into one of 3 groups: Middle Cerebral Artery Occlusion (MCAO) plus pyruvate treatment, MCAO plus placebo treatment, and sham operated rats. Post-MCAO depressive and anxiety-like behavior was assessed, along with neurological status, brain infarct zone, brain edema, blood brain barrier (BBB) breakdown, cerebrospinal fluid and blood glutamate levels. Anxiety-like behavior and levels of blood alanine and α-ketoglutarate were measured in naïve rats treated with pyruvate, as a control. Post-stroke neurological deficit with concurrent elevation in glutamate levels were demonstrated, with peak glutamate levels 24 h after MCAO. Treatment with pyruvate led to reduced glutamate levels 24 h after MCAO and improved neurologic recovery. Pyruvate treatment reduced lesion volume, brain edema and the extent of BBB permeability 24 h post-MCAO. Naïve rats treated with pyruvate showed increased levels of α-ketoglutarate. Rats demonstrated post-stroke depressive behavior that was improved by the administration of pyruvate. There was less anxiety-like behavior in post-stroke rats treated with placebo in comparison to the post-stroke rats treated with pyruvate or sham operated rats. Glutamate scavenging with pyruvate appears to be an effective as a method in providing neuroprotection following stroke and as a therapeutic option for the treatment of PSD by reducing the consequent elevations in CNS glutamate levels.
•Post-stroke neurological deficit with concurrent elevation in glutamate levels were demonstrated, with peak glutamate levels 24 h after MCAO.•Treatment with pyruvate led to reduced glutamate levels 24 h after MCAO and improved neurologic recovery.•Rats demonstrated post-stroke depressive behavior that was improved by the administration of pyruvate.•There was less anxiety-like behavior in post-stroke rats treated with placebo in comparison to the post-stroke rats treated with pyruvate or sham operated rats.•Our main conclusion was that glutamate scavenging with pyruvate appears to be an effective as a method in providing neuroprotection following stroke and as a therapeutic option for the treatment of PSD by reducing the consequent elevations in CNS glutamate levels.
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