Regional pulmonary response to a methacholine challenge using hyperpolarized 3He magnetic resonance imaging

Background and objective: Spirometry is insensitive to small airway abnormalities in asthma. Our objective was to evaluate regional lung structure and function using hyperpolarized ³He magnetic resonance imaging (MRI) before, during and after a methacholine challenge (MCh). Methods: Twenty‐five asthmatics (mean age = 34 ± 11 years) and eight healthy volunteers (HV) (mean age = 33 ± 11 years) underwent spirometry, plethysmography and hyperpolarized ³He MRI prior to a MCh. MRI was repeated following the MCh and again 25 min after salbutamol administration. ³He MRI gas distribution was quantified using semiautomated segmentation of the ventilation defect percent (VDP). Tissue microstructure was measured using the ³He apparent diffusion coefficient (ADC). Analysis of variance with repeated measures was used to evaluate changes at each time point as well as to determine interactions between regions of interest (ROI) and subject group. Pearson's correlations were performed to evaluate associations between ³He MRI measurements and established clinical measures. Results: In asthmatics, but not HV, whole‐lung ADC was increased post‐MCh (P < 0.01). In asthmatics only, ADC was increased post‐MCh in posterior ROI (P < 0.01) and all ROI in the superior‐inferior direction (P < 0.01). VDP was increased in posterior and inferior ROI (P < 0.001). There was a correlation between VDP and specific airway resistance (r = 0.74, P < 0.0001), dyspnoea score (r = 0.66, P < 0.01) and fractional exhaled nitric oxide (r = 0.45, P < 0.05). Conclusions: We evaluated the regional pulmonary response to methacholine and salbutamol using ³He MRI and showed heterogeneous VDP and ADC consistent with bronchoconstriction and gas trapping, respectively, post‐MCh. These regional alterations resolved post‐salbutamol.     

Brain response to visceral aversive conditioning: a functional magnetic resonance imaging study

BACKGROUND & AIMS: Brain-imaging studies to date have confounded visceral pain perception with anticipation. We used functional magnetic resonance imaging of the human brain to study the neuroanatomic network involved in aversive conditioning of visceral pain and, thus, anticipation. METHODS: Eight healthy volunteers (5 male) participated in the study. We used a classic conditioning paradigm in which 3 neutral stimuli (differently colored circles) that acted as conditioned stimuli were paired with painful esophageal distention, air puff to the wrist, or nothing, which acted as unconditioned stimuli. Neural activity was measured during learning, anticipation (pairing only 50% of conditioned stimuli with their unconditioned stimuli), and extinction (unpaired conditioned stimuli) phases. For magnetic resonance imaging, axial slices depicting blood oxygen level-dependent contrast were acquired with a 1.5-T system. RESULTS: Neural responses during the learning phase included areas commonly associated with visceral pain (anterior cingulate cortex, insula, and primary and secondary somatosensory cortices) and innocuous somatosensory perception (primary and secondary somatosensory cortices and insula). During the anticipation and extinction phases of aversive stimulation, brain activity resembled that seen during actual painful esophageal stimulation. In contrast, anticipation and extinction of the innocuous somatic stimulus failed to show that effect. CONCLUSIONS: We have shown that actual and anticipated visceral pain elicit similar cortical responses. These results have implications for the design and interpretation of brain-imaging studies of visceral pain. They not only contribute to our understanding of the processing of visceral pain, but also have clinical implications for the management of chronic pain states.     

Gender and age at drinking onset affect voluntary alcohol consumption but neither the alcohol deprivation effect nor the response to stress in mice

Background: Epidemiological studies suggest that initiation of alcohol drinking at an early age is associated with an increased risk of developing an alcohol use disorder later in life. Nevertheless, relatively few studies using animal models have investigated the relationship between age of onset of drinking and ethanol drinking patterns in adulthood. Besides age at drinking onset, other factors such as gender could also affect the pattern of development of alcohol consumption. In rodents, many studies have shown that females drink more than males. However, even if it is assumed that hormonal changes occurring at puberty could explain these differences, only one study performed in rats has investigated the emergence of sex‐specific alcohol drinking patterns in adolescence and the transition from adolescence to adulthood. The aim of the present study was to compare the acquisition of voluntary alcohol consumption, relapse‐like drinking (the Alcohol Deprivation Effect—ADE) and stress‐induced alcohol drinking in male and female outbred mice that acquired alcohol consumption during adolescence or adulthood. Methods: Separate groups of naïve female and male WSC‐1 mice aged ± 28 days (adolescents) or ±70 days (adults) were given ad libitum access to water and 6% ethanol solution for 8 weeks (1st to 8th week) before undergoing a 2‐week deprivation phase (9th and 10th week). After the deprivation period, 2‐bottle preference testing (ethanol vs. water) resumed for 3 weeks (11th to 13th). During the 13th week, all animals were subjected to restraint stress for 2 consecutive days. Results: Over the entire time course of the experiment, ethanol intake and preference increased in females (both adults and adolescents). Adolescent animals (both females and males) showed a transient increase in alcohol consumption and preference compared to adults. However, by the end of continuous alcohol exposure (when all mice were adults), ethanol intake was not affected by age at drinking onset. A deprivation phase was followed by a rise in ethanol intake (ADE) that was not affected by sex or age. Finally, stress did not alter alcohol self‐administration either during or after its occurrence. Conclusions: Emergence of greater alcohol consumption in adult females does not seem to be limited to a specific developmental period (i.e., puberty). Age of voluntary drinking onset (adolescence vs. adulthood) does not affect eventual alcohol intake in adult WSC‐1 mice and does not modify the transient increase in ethanol consumption after alcohol deprivation.     

Functional remnant liver volumetry using Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) predicts post-hepatectomy liver failure in resection of more than one segment

BackgroundGd-EOB-DTPA-enhanced magnetic resonance imaging (EOB-MRI) can be used for evaluating liver functional reserve. We assessed whether functional remnant liver volumetry (FRLV) using EOB-MRI predicted post-hepatectomy liver failure (PHLF) in resection of more than one segment.MethodsWe retrospectively analyzed 155 cases of hepatectomy of more than one segment. For assessment of FRLV, signal intensity (SI) of remnant liver was measured in T1-weighted images. Functional remnant liver score was derived by division of SI of liver by SI of muscle (or spleen), resulting in liver-to-muscle ratio (LMR) and liver-to-spleen ratio (LSR). FRLV were calculated by multiplying LMR (or LSR) and remnant liver volume. We investigated preoperative factors predicting PHLF (≥grade B) in study cohort (all cases except for portal vein embolization [PVE], n = 129) and validation cohort (PVE cases, n = 26).ResultsIn study cohort, PHLF occurred in 5 patients (3.9%). In multivariate analysis, FRLV (LMR) was the most reliable predictor of PHLF (P = 0.013). The cutoff value of FRLV (LMR) predicting PHLF was 615 mL/m² (AUC: 0.939). In validation cohort (n = 26), the cutoff value of FRLV (LMR) indicated reliable results, sensitivity (100%), specificity (77.3%), and accuracy (80.8%).ConclusionsFRLV using LMR could precisely predict PHLF of more than one segment, and was useful even in patients who underwent PVE.     

Diabetes dietary management alters responses to food pictures in brain regions associated with motivation and emotion: a functional magnetic resonance imaging study

Aims/hypothesis  We hypothesised that living with type 2 diabetes would enhance responses to pictures of foods in brain regions known to be involved in learnt food sensory motivation and that these stronger activations would relate to scores for dietary adherence in diabetes and to measures of potential difficulties in adherence. Methods  We compared brain responses to food images of 11 people with type 2 diabetes and 12 healthy control participants, matched for age and weight, using functional magnetic resonance imaging (fMRI). Results  Having type 2 diabetes increased responses to pictured foods in the insula, orbitofrontal cortex (OFC) and basal ganglia and, within these regions, the effect of the fat content of the foods was larger in participants with type 2 diabetes than in healthy controls. Furthermore, increased activation to food within the insula and OFC positively correlated with external eating, dietary self-efficacy and dietary self-care. In contrast, responses within subcortical structures (amygdala and basal ganglia) were positively correlated with emotional eating and rated appetite for the food stimuli and negatively correlated with dietary self-care. Conclusions/interpretation  Type 2 diabetes is associated with changes in brain responses to food that are modulated by dietary self-care. We propose that this is linked to the need to follow a life-long restrictive diet. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

Myocardial iron overload assessed by magnetic resonance imaging (MRI)T2* in multi-transfused patients with thalassemia and acquired anemias

Background

Cardiac complications secondary to iron overload remain a significant matter in patients with transfusion dependent anemias.

Patients and methods

To evaluate cardiac siderosis, Magnetic resonance imaging T2* (MRI T2*) was performed in 3 cohorts of transfusion dependent patients: 99 with thalassemia major (TM), 20 with thalassemia intermedia (TI), and 10 with acquired anemias (AA). Serum ferritin was measured and all patients underwent echocardiographic evaluation.

Results

In TM patients cardiac T2* pathologic values (below 20 ms) were found in 37 patients. Serum ferritin was negatively associated with age (r = −0.32, p = 0.001) and weakly with T2* values (r = −0.19, p = 0.057). A positive correlation was found between T2* and LVEF (r = 0.27, p = 0.006). Out of 37 patients with T2* < 20 ms, 18 (48%) had serum ferritin values < 1000 ng/ml. In TI cohort, 3 patients had cardiac T2* pathologic values. In AA cohort, pathologic T2* values were found in 2 patients, who received 234 and 199 PRBC units, respectively, and were both on chelation therapy (in one patient ferritin value was 399 ng/ml). T2* values were negatively associated, but not significantly, with the number of PRBC transfused (r = −0.53, p = 0.07).

Conclusion

In our experience, 37% of TM patients had a myocardial iron overload assessed by MRI T2*; this value is higher than in TI patients. Serum ferritin measurement was a poor predictor of myocardial siderosis. In patients with AA, more than 200 PRBC units transfused were required to induce cardiac hemosiderosis, in spite of chelation therapy and, in one patient, of normal ferritin values.     

Pancreatic duct changes are not associated with early signs of chronic pancreatitis at magnetic resonance imaging (MRI) in patients with primary sclerosing cholangitis

Abstract

Objective. The association between chronic pancreatitis (CP) and primary sclerosing cholangitis (PSC) has been reported previously. The aims of the present study were to evaluate the presence of early pancreatic abnormalities and duct changes, using MRCP/MRI in PSC and to evaluate possible risk factors for these changes and their clinical importance. Materials and methods. One hundred and three patients with PSC were identified among all MRI liver/pancreas referrals in 2001–2005. MRCP was used to grade pancreatic duct changes in three groups: grade 0 (normal), grade 1 (mild) and grade 2 (severe). For detection of early MRI signs of CP, the pancreas-spleen signal intensity ratio (SIR), the arterial and early venous phase ratio (A/PV ratio) and the age-related size of the pancreas were evaluated. Results. Pancreatic duct changes were found in 24% of the PSC patients. The pancreatic duct changes were associated with extrahepatic biliary involvement and long duration of PSC but not associated with pancreas-spleen SIR, A/PV ratio, pancreas size, previous post-ERCP or acute pancreatitis. Severe pancreatic duct changes were significantly associated to abdominal pain. Clinically significant CP was seen in one PSC patient (1%). Conclusions. Pancreatic duct changes are associated with extrahepatic bile duct strictures and not with the early MRI signs of CP. Therefore, pancreatic duct changes seem to be part of the spectrum of PSC and should not be defined as CP. Pancreatic duct changes are of limited clinical importance but may contribute to abdominal pain in PSC.     

Brain activation in response to visual sexual stimuli in male patients with right middle cerebral artery infarction: The first case-control functional magnetic resonance imaging study

Sexual dysfunction is a common problem after cerebral infarction; however, little is known about sexual arousal in poststroke patients. Thus, this study aimed to investigate brain activation in response to visual sexual stimuli in patients with right middle cerebral artery (MCA) territory infarction using functional magnetic resonance imaging (fMRI). Using fMRI in 20 participants (11 right MCA infarction patients and 9 age-matched healthy controls), we assessed brain activation elicited by visual sexual stimuli (erotic images) and visual nonsexual stimuli (landscape images). In right MCA infarction patients, the left dorsolateral prefrontal cortex and the left frontal subgyral area were more strongly activated by visual sexual stimuli than by nonvisual sexual stimuli. Brain areas that were more activated by visual sexual stimuli in right MCA infarction patients than in controls included the right parahippocampal gyrus and the bilateral frontal subgyral area. These fMRI results suggest that brain activation patterns in response to visual sexual stimuli might be influenced by right MCA infarction. Further research is needed to explore the association between sexual dysfunction and brain activation in poststroke patients.     

Maximal tumor diameter in the preoperative tumor magnetic resonance imaging (MRI) T2 image is associated with prognosis of Grade II Glioma

Factors associated with the prognosis of low-grade glioma remain undefined. In this study, we examined whether the maximal tumor diameter in the preoperative tumor magnetic resonance imaging (MRI) T2 image is associated with the prognosis of grade II gliomas patients, aiming to provide insights into the clinical prediction of patient outcome.We retrospectively analyzed the clinical data of patients with Grade II glioma, who were hospitalized in Xiangya Hospital, Central South University, from 2011 to 2016. Kaplan–Meier and Cox proportional hazards analyses were performed to determine the association between maximal tumor diameter and prognosis.A total of 90 patients with grade II glioma were included in this study. Mean patient age was 37.7 ± 13.0 years, and 58.9% of them were male. Kaplan–Meier survival analysis of overall survival (overall survival [OS], P = .009) and event-free survival (EFS, P = .002) revealed statistically significant differences between the patients with lesion diameter <7 cm and those with lesion diameter ≥7 cm. The maximal tumor diameter in the preoperative tumor MRI T2 image was identified as a prognostic factor of OS (P = .013), while constituting an independent risk factor for EFS (P = .002) alongside elevated histological grade after recurrence (P = .006).The maximal tumor diameter in the preoperative tumor MRI T2 image independently predicts OS and EFS in patients with grade II glioma.