The association between intraoperative hyperglycemia and cerebrovascular markers.

BACKGROUND AND PURPOSE: Hyperglycemia can lead to an increased rate of apoptosis of microglial cells and to damaged neurons. The relation between hyperglycemia and cerebrovascular markers on MRI is unknown. Our aim was to study the association between intraoperative hyperglycemia and cerebrovascular markers. METHODS: In this further analysis of a subgroup investigation of the BIOCOG study, 65 older non-demented patients (median 72 years) were studied who underwent elective surgery of ≥ 60 minutes. Intraoperative blood glucose maximum was determined retrospectively in each patient. In these patients, preoperatively and at 3 months follow-up a MRI scan was performed and white matter hyperintensity (WMH) volume and shape, infarcts, and perfusion parameters were determined. Multivariable logistic regression analyses were performed to determine associations between preoperative cerebrovascular markers and occurrence of intraoperative hyperglycemia. Linear regression analyses were performed to assess the relation between intraoperative hyperglycemia and pre- to postoperative changes in WMH volume. Associations between intraoperative hyperglycemia and postoperative WMH volume at 3 months follow-up were also assessed by linear regression analyses. RESULTS: Eighteen patients showed intraoperative hyperglycemia (glucose maximum ≥ 150 mg/dL). A preoperative more smooth shape of periventricular and confluent WMH was related to the occurrence of intraoperative hyperglycemia [convexity: OR 33.318 (95 % CI (1.002 - 1107.950); p = 0.050]. Other preoperative cerebrovascular markers were not related to the occurrence of intraoperative hyperglycemia. Intraoperative hyperglycemia showed no relation with pre- to postoperative changes in WMH volume nor with postoperative WMH volume at 3 months follow-up. CONCLUSIONS: We found that a preoperative more smooth shape of periventricular and confluent WMH was related to the occurrence of intraoperative hyperglycemia. These findings may suggest that a similar underlying mechanism leads to a certain pattern of vascular brain abnormalities and an increased risk of hyperglycemia.

Low interrater reliability of brachial plexus MRI in chronic inflammatory neuropathies.

INTRODUCTION: Magnetic resonance imaging of the brachial plexus shows nerve thickening in approximately half of the patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN). The reliability of qualitative evaluation of brachial plexus MRI has not been studied previously. METHODS: We performed an interrater study in a retrospective cohort of 19 patients with CIDP, 17 patients with MMN, and 14 controls. The objective was to assess interrater variability between radiologists by using a predefined scoring system that allowed the distinction of no, possible, or definite nerve thickening. RESULTS: Raters agreed in 26 of 50 (52%) brachial plexus images; κ-coefficient was 0.30 (SE 0.08, 95% confidence interval 0.14-0.46, P < .0005). DISCUSSION: Our results provide evidence that interrater reliability of qualitative evaluation of brachial plexus MRI is low. Objective criteria for abnormality are required to optimize the diagnostic value of MRI for inflammatory neuropathies.

Predicting the presence of macrovascular causes in non-traumatic intracerebral haemorrhage: the DIAGRAM prediction score.

OBJECTIVE: A substantial part of non-traumatic intracerebral haemorrhages (ICH) arises from a macrovascular cause, but there is little guidance on selection of patients for additional diagnostic work-up. We aimed to develop and externally validate a model for predicting the probability of a macrovascular cause in patients with non-traumatic ICH. METHODS: The DIagnostic AngioGRAphy to find vascular Malformations (DIAGRAM) study (n=298; 69 macrovascular cause; 23%) is a prospective, multicentre study assessing yield and accuracy of CT angiography (CTA), MRI/ magnetic resonance angiography (MRA) and intra-arterial catheter angiography in diagnosing macrovascular causes in patients with non-traumatic ICH. We considered prespecified patient and ICH characteristics in multivariable logistic regression analyses as predictors for a macrovascular cause. We combined independent predictors in a model, which we validated in an external cohort of 173 patients with ICH (78 macrovascular cause, 45%). RESULTS: Independent predictors were younger age, lobar or posterior fossa (vs deep) location of ICH, and absence of small vessel disease (SVD). A model that combined these predictors showed good performance in the development data (c-statistic 0.83; 95% CI 0.78 to 0.88) and moderate performance in external validation (c-statistic 0.66; 95% CI 0.58 to 0.74). When CTA results were added, the c-statistic was excellent (0.91; 95% CI 0.88 to 0.94) and good after external validation (0.88; 95% CI 0.83 to 0.94). Predicted probabilities varied from 1% in patients aged 51-70 years with deep ICH and SVD, to more than 50% in patients aged 18-50 years with lobar or posterior fossa ICH without SVD. CONCLUSION: The DIAGRAM scores help to predict the probability of a macrovascular cause in patients with non-traumatic ICH based on age, ICH location, SVD and CTA.

Mood problems increase the risk of mortality in patients with lacunar infarcts: the SMART-MR study.

OBJECTIVE: A relationship between depression and mortality has been well established, but underlying mechanisms remain unclear. We investigated the influence of cerebral small vessel disease (CSVD), characterized by white matter lesions (WMLs) and lacunar infarcts, on the relationship between mood mortality during 6 years follow-up. METHODS: Mood problems were assessed with the mental component summary of the 36-item Short-Form Medical Outcomes Study in 1110 patients with symptomatic atherosclerotic disease (mean age 59 years). Volumetric WML estimates were obtained with 1.5-T magnetic resonance imaging; lacunar infarcts were scored visually. Cox regression models were adjusted for age, sex, vascular risk, physical functioning, antidepressants and infarcts. We adjusted for CSVD to examine whether it may be an intermediate or confounding factor. Second, we added interaction terms to investigate whether associations differed between patients with CSVD (absent/present). RESULTS: Patients in the lowest quartile of mental functioning, representing most severe mood problems, were at higher, although not significant, risk of death (hazard ratio [HR] = 1.47, 95% confidence interval [CI] = 0.94-2.30) compared with patients in higher quartiles. Adjustment for CSVD did not change this association. Lacunar infarcts, not WML, modified the association of mood problems with mortality (p value for interaction = .01); mood problems strongly increased the risk of mortality in patients with lacunar infarcts (HR = 2.75, 95% CI = 1.41-5.38) but not in those without it (HR = 0.78, 95% CI = 0.39-1.57). CONCLUSIONS: Patients with lacunar infarcts may be especially vulnerable for the effect of mood problems on mortality.

Intracranial vessel wall lesions on 7T MRI and MRI features of cerebral small vessel disease: The SMART-MR study.

The etiology of cerebral small vessel disease (CSVD) is the subject of ongoing research. Although intracranial atherosclerosis (ICAS) has been proposed as a possible cause, studies on their relationship remain sparse. We used 7 T vessel wall magnetic resonance imaging (MRI) to study the association between intracranial vessel wall lesions-a neuroimaging marker of ICAS-and MRI features of CSVD. Within the SMART-MR study, cross-sectional analyses were performed in 130 patients (68 ± 9 years; 88% male). ICAS burden-defined as the number of vessel wall lesions-was determined on 7 T vessel wall MRI. CSVD features were determined on 1.5 T and 7 T MRI. Associations between ICAS burden and CSVD features were estimated with linear or modified Poisson regression, adjusted for age, sex, vascular risk factors, and medication use. In 125 patients, ≥1 vessel wall lesions were found (mean 8.5 ± 5.7 lesions). ICAS burden (per + 1 SD) was associated with presence of large subcortical and/or cortical infarcts (RR = 1.65; 95%CI: 1.12-2.43), lacunes (RR = 1.45; 95% CI: 1.14-1.86), cortical microinfarcts (RR = 1.48; 95%CI: 1.13-1.94), and total white matter hyperintensity volume (b = 0.24; 95%CI: 0.02-0.46). Concluding, patients with a higher ICAS burden had more CSVD features, although no evidence of co-location was observed. Further longitudinal studies are required to determine if ICAS precedes development of CSVD.

Cortical cerebral microinfarcts on 7T MRI: Risk factors, neuroimaging correlates and cognitive functioning - The Medea-7T study.

We determined the occurrence and association of cortical cerebral microinfarcts (CMIs) at 7 T MRI with risk factors, neuroimaging markers of small and large vessel disease, and cognitive functioning. Within the Medea-7T study, a diverse cohort of older persons with normal cognition, patients with vascular disease, and memory clinic patients, we included 386 participants (68 ± 9 years) with available 7 T and 1.5 T/3T brain MRI, and risk factor and neuropsychological data. CMIs were found in 10% of participants and were associated with older age (RR = 1.79 per +10 years, 95%CI 1.28-2.50), history of stroke or TIA (RR = 4.03, 95%CI 2.18-7.43), cortical infarcts (RR = 5.28, 95%CI 2.91-9.55), lacunes (RR = 5.66, 95%CI 2.85-11.27), cerebellar infarcts (RR = 2.73, 95%CI 1.27-5.84) and decreased cerebral blood flow (RR = 1.35 per -100 ml/min, 95%CI 1.00-1.83), after adjustment for age and sex. Furthermore, participants with >2 CMIs had 0.5 SD (95%CI 0.05-0.91) lower global cognitive performance, compared to participants without CMIs. Our results indicate that CMIs on 7 T MRI are observed in vascular and memory clinic patients with similar frequency, and are associated with older age, history of stroke or TIA, other brain infarcts, and poorer global cognitive functioning.

Preoperative MRI brain phenotypes are related to postoperative delirium in older individuals.

The underlying structural correlates of predisposition to postoperative delirium remain largely unknown. A combined analysis of preoperative brain magnetic resonance imaging (MRI) markers could improve our understanding of the pathophysiology of delirium. Therefore, we aimed to identify different MRI brain phenotypes in older patients scheduled for major elective surgery, and to assess the relation between these phenotypes and postoperative delirium. Markers of neurodegenerative and neurovascular brain changes were determined from MRI brain scans in older patients (n = 161, mean age 71, standard deviation 5 years), of whom 24 (15%) developed delirium. A hierarchical cluster analysis was performed. We found six distinct groups of patients with different MRI brain phenotypes. Logistic regression analysis showed a higher odds of developing postoperative delirium in individuals with multi-burden pathology (n = 15 (9%), odds ratio (95% confidence interval): 3.8 (1.1-13.0)). In conclusion, these results indicate that different MRI brain phenotypes are related to a different risk of developing delirium after major elective surgery. MRI brain phenotypes could assist in an improved understanding of the structural correlates of predisposition to postoperative delirium.

Preoperative brain MRI features and occurrence of postoperative delirium.

OBJECTIVE: Delirium is a frequent complication after surgery with important negative outcomes for affected patients and society. However, it is still largely unknown why some patients have a predisposition for delirium and others not. To increase our understanding of the neural substrate of postoperative delirium, we studied the association between preoperative brain MRI features and the occurrence of delirium after major surgery. METHODS: A group of 413 patients without dementia (Mean 72 years, SD: 5) was included in a prospective observational two-center study design. The study was conducted at Charité Universitätsmedizin (Berlin, Germany) and the University Medical Center Utrecht (Utrecht, The Netherlands). We measured preoperative brain volumes (total brain, gray matter, white matter), white matter hyperintensity volume and shape, brain infarcts and cerebral perfusion, and used logistic regression analysis adjusted for age, sex, intracranial volume, study center and type of surgery. RESULTS: Postoperative delirium was present in a total of 70 patients (17%). Preoperative cortical brain infarcts increased the risk of postoperative delirium, although this did not reach statistical significance (OR (95%CI): 1.63 (0.84-3.18). Furthermore, we found a trend for an association of a more complex shape of white matter hyperintensities with occurrence of postoperative delirium (OR (95%CI): 0.97 (0.95-1.00)). Preoperative brain volumes, white matter hyperintensity volume, and cerebral perfusion were not associated with occurrence of postoperative delirium. CONCLUSION: Our study suggests that patients with preoperative cortical brain infarcts and those with a more complex white matter hyperintensity shape may have a predisposition for developing delirium after major surgery.

Quantitative assessment of brachial plexus MRI for the diagnosis of chronic inflammatory neuropathies.

OBJECTIVE: This study aimed at developing a quantitative approach to assess abnormalities on MRI of the brachial plexus and the cervical roots in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN) and to evaluate interrater reliability and its diagnostic value. METHODS: We performed a cross-sectional study in 50 patients with CIDP, 31 with MMN and 42 disease controls. We systematically measured cervical nerve root sizes on MRI bilaterally (C5, C6, C7) in the coronal [diameter (mm)] and sagittal planes [area (mm2)], next to the ganglion (G0) and 1 cm distal from the ganglion (G1). We determined their diagnostic value using a multivariate binary logistic model and ROC analysis. In addition, we evaluated intra- and interrater reliability. RESULTS: Nerve root size was larger in patients with CIDP and MMN compared to controls at all predetermined anatomical sites. We found that nerve root diameters in the coronal plane had optimal reliability (intrarater ICC 0.55-0.87; interrater ICC 0.65-0.90). AUC was 0.78 (95% CI 0.69-0.87) for measurements at G0 and 0.81 (95% CI 0.72-0.91) for measurements at G1. Importantly, our quantitative assessment of brachial plexus MRI identified an additional 10% of patients that showed response to treatment, but were missed by nerve conduction (NCS) and nerve ultrasound studies. CONCLUSION: Our study showed that a quantitative assessment of brachial plexus MRI is reliable. MRI can serve as an important additional diagnostic tool to identify treatment-responsive patients, complementary to NCS and nerve ultrasound.

Intracranial aneurysms treated with coil placement: test characteristics of follow-up MR angiography--multicenter study.

PURPOSE: To determine the test characteristics of magnetic resonance (MR) angiography in the assessment of occlusion of aneurysms treated with coil placement. MATERIALS AND METHODS: This was an ethics committee-approved multicenter study. written informed consent was obtained in 311 patients with 343 aneurysms, who had been treated with coil placement and were scheduled for routine follow-up with intraarterial digital subtraction angiography (DSA). Thirty-five patients participated two or three times. Either 3.0- or 1.5-T time-of-flight (TOF) and contrast material-enhanced MR angiography were performed in addition to intraarterial DSA. Aneurysm occlusion was evaluated by independent readers at DSA and MR angiography. The test characteristics of MR angiography were assessed by using DSA as the standard. The area under the receiver operating characteristic curve (AUC) was calculated for 3.0- versus 1.5-T MR angiography and for TOF versus contrast-enhanced MR angiography, and factors associated with discrepancies between MR angiography and DSA were assessed with logistic regression. RESULTS: Aneurysm assessments (n = 381) at DSA and MR angiography were compared. Incomplete occlusion was seen at DSA in 88 aneurysms (23%). Negative predictive value of MR angiography was 94% (95% confidence interval [CI]: 91%, 97%), positive predictive value was 69% (95% CI: 60%, 78%), sensitivity was 82% (95% CI: 72%, 89%), and specificity was 89% (95% CI: 85%, 93%). AUCs were similar for 3.0- (0.90 [95% CI: 0.86, 0.94]) and 1.5-T MR (0.87 [95% CI: 0.78, 0.95]) and for TOF MR (0.86 [95% CI: 0.81, 0.91]) versus contrast-enhanced MR (0.85 [95% CI: 0.80, 0.91]). A small residual lumen (odds ratio, 2.1 [95% CI: 1.1, 4.3]) and suboptimal projection at DSA (odds ratio, 5.5 [95% CI: 1.5, 21.0]) were independently associated with discordance between intraarterial DSA and MR angiography. CONCLUSION: Documentation of good diagnostic performance of TOF MR angiography at both 1.5 and 3.0 T in the current study represents an important step toward replacing intraarterial DSA with MR angiography in the follow-up of patients with aneurysms treated with coils.

COL4A1 mutation in two preterm siblings with antenatal onset of parenchymal hemorrhage.

OBJECTIVE: To report the presence of intracerebral hemorrhage and porencephaly, both present at birth, in two preterm infants with a mutation in the collagen 4 A1 gene. METHODS: Two preterm infants with antenatal intracerebral hemorrhage and established porencephaly, as well as their affected mother and grandfather, underwent neurological and ophthalmological examination and magnetic resonance imaging of the brain. Mutation analysis of the COL4A1 gene was performed in the infants and in their mother. RESULTS: Both infants had a novel G1580R mutation in the COL4A1 gene, encoding procollagen type IV alpha1. A history of mild antenatal trauma was present in the first but not in the second infant. Both preterm infants were asymptomatic at birth. The intracerebral hemorrhage and porencephaly were diagnosed with cranial ultrasound examination and were subsequently confirmed with magnetic resonance imaging. Leukoencephalopathy was present in the mother and in her father. INTERPRETATION: Mutation of the COL4A1 gene appears to be a risk factor of antenatal intracerebral hemorrhage followed by porencephaly in the preterm newborn.

White matter lesions and lacunar infarcts are independently and differently associated with brain atrophy: the SMART-MR study.

OBJECTIVE: To investigate the independent association of white matter lesions (WML) and lacunar infarcts (LI) with measures of global brain atrophy on MRI. METHODS: Within the SMART-MR study, a cohort study among patients with manifest arterial disease, cross-sectional analyses were performed in 840 patients (mean age 58 +/- 10 years, 80% male) without cortical, large subcortical or infratentorial infarcts. Brain segmentation was used to quantify volumes of brain tissue, cerebrospinal fluid and WML. Total brain volume, ventricular volume and cortical gray matter volume were divided by intracranial volume to obtain brain parenchymal fraction (BPF), ventricular fraction (VF) and cortical gray matter fraction (GMF). Location and number of infarcts were rated visually. RESULTS: Mean +/- SD BPF was 79.3 +/- 2.8%, mean +/- SD VF was 2.01 +/- 0.95%, and mean +/- SD GMF was 36.6 +/- 3.3%. Linear regression analyses, adjusted for age, sex, vascular risk factors, intima media thickness and LI showed that in patients with moderate to severe WML (upper quartile) BPF was lower (-0.51%; 95% CI -0.93 to -0.08%), VF was higher (0.48%; 95% CI 0.31-0.65%) and GMF was lower (-1.48%; 95% CI -2.07 to -0.88%) than in patients with few WML (lower quartile). Presence of LI was associated with lower BPF (-0.52%; 95% CI -0.96 to -0.07%) and higher VF (0.25%; 95% CI 0.07-0.42%), but not with GMF, independent of WML and other potential confounders. CONCLUSION: WML are associated with total, subcortical and cortical brain atrophy, whereas LI are associated with total and subcortical atrophy, but not with cortical atrophy, suggesting an independent role for WML and LI in the pathogenesis of brain atrophy.

MRI phenotypes of the brain are related to future stroke and mortality in patients with manifest arterial disease: The SMART-MR study.

Neurodegenerative and neurovascular diseases lead to heterogeneous brain abnormalities. A combined analysis of these abnormalities by phenotypes of the brain might give a more accurate representation of the underlying aetiology. We aimed to identify different MRI phenotypes of the brain and assessed the risk of future stroke and mortality within these subgroups. In 1003 patients (59 ± 10 years) from the Second Manifestations of ARTerial disease-Magnetic Resonance (SMART-MR) study, different quantitative 1.5T brain MRI markers were used in a hierarchical clustering analysis to identify 11 distinct subgroups with a different distribution in brain MRI markers and cardiovascular risk factors, and a different risk of stroke (Cox regression: from no increased risk compared to the reference group with relatively few brain abnormalities to HR = 10.34; 95% CI 3.80↔28.12 for the multi-burden subgroup) and mortality (from no increased risk compared to the reference group to HR = 4.00; 95% CI 2.50↔6.40 for the multi-burden subgroup). In conclusion, within a group of patients with manifest arterial disease, we showed that different MRI phenotypes of the brain can be identified and that these were associated with different risks of future stroke and mortality. These MRI phenotypes can possibly classify individual patients and assess their risk of future stroke and mortality.

Vascular Risk Factors of Hippocampal Subfield Volumes in Persons without Dementia: The Medea 7T Study.

BACKGROUND: Vascular risk factors have been associated with risk of Alzheimer's disease (AD) and volume loss of the hippocampus, but the associations with subfields of the hippocampus are understudied. Knowing if vascular risk factors contribute to hippocampal subfield atrophy may improve our understanding of vascular contributions to neurodegenerative diseases. OBJECTIVE: To investigate the associations between age, sex, and vascular risk factors with hippocampal subfields volumes on 7T MRI in older persons without dementia. METHODS: From the Medea 7T study, 283 participants (67±9 years, 68% men) without dementia had 7T brain MRI and hippocampal subfield segmentation. Subfields were automatically segmented on the 3D T2-weighted 7T images with ASHS software. Using linear mixed models, we estimated adjusted associations of age, sex, and vascular risk factors with z-scores of volumes of the entorhinal cortex (ERC), subiculum (SUB), Cornu Ammonis (CA)1, CA2, CA3, CA4, and dentate gyrus (DG), and tail as multivariate correlated outcomes. RESULTS: Increasing age was associated with smaller volumes in all subfields, except CA4/DG. Current smoking was associated with smaller ERC and SUB volumes; moderate alcohol use with smaller CA1 and CA4/DG, obesity with smaller volumes of ERC, SUB, CA2, CA3, and tail; and diabetes mellitus with smaller SUB volume. Sex, former smoking, and hypertension were not associated with subfield volumes. When formally tested, no risk factor affected the subfield volumes differentially. CONCLUSION: Several vascular risk factors were associated with smaller volumes of specific hippocampal subfields. However, no statistical evidence was found that subfields were differentially affected by these risk factors.

The association between lacunes and white matter hyperintensity features on MRI: The SMART-MR study.

Lacunes and white matter hyperintensities (WMHs) are features of cerebral small vessel disease (CSVD) that are associated with poor functional outcomes. However, how the two are related remains unclear. In this study, we examined the association between lacunes and several WMH features in patients with a history of vascular disease. A total of 999 patients (mean age 59 ± 10 years) with a 1.5 T brain magnetic resonance imaging (MRI) scan were included from the SMART-MR study. Lacunes were scored visually and WMH features (volume, subtype and shape) were automatically determined. Analyses consisted of linear and Poisson regression adjusted for age, sex, and total intracranial volume (ICV). Patients with lacunes (n = 188; 19%) had greater total (B = 1.03, 95% CI: 0.86 to 1.21), periventricular/confluent (B = 1.08, 95% CI: 0.89 to 1.27), and deep (B = 0.71, 95% CI: 0.44 to 0.97) natural log-transformed WMH volumes than patients without lacunes. Patients with lacunes had an increased risk of confluent type WMHs (RR = 2.41, 95% CI: 1.98 to 2.92) and deep WMHs (RR = 1.41, 95% CI: 1.22 to 1.62) and had a more irregular shape of confluent WMHs than patients without lacunes, independent of total WMH volume. In conclusion, we found that lacunes on MRI were associated with WMH features that correspond to more severe small vessel changes, mortality, and poor functional outcomes.

Total cerebral blood flow, white matter lesions and brain atrophy: the SMART-MR study.

We investigated whether total cerebral blood flow (CBF) was associated with brain atrophy, and whether this relation was modified by white matter lesions (WML). Within the Second Manifestations of ARTerial disease-magnetic resonance (SMART-MR) study, a prospective cohort study among patients with arterial disease, cross-sectional analyses were performed in 828 patients (mean age 58+/-10 years, 81% male) with quantitative flow, atrophy, and WML measurements on magnetic resonance imaging (MRI). Total CBF was measured with MR angiography and was expressed per 100 mL brain volume. Total brain volume and ventricular volume were divided by intracranial volume to obtain brain parenchymal fraction (BPF) and ventricular fraction (VF). Lower BPF indicates more global brain atrophy, whereas higher VF indicates more subcortical brain atrophy. Mean CBF was 52.0+/-10.2 mL/min per 100 mL, mean BPF was 79.2+/-2.9%, and mean VF was 2.03+/-0.96%. Linear regression analyses showed that lower CBF was associated with more subcortical brain atrophy, after adjusting for age, sex, vascular risk factors, intima-media thickness, and lacunar infarcts, but only in patients with moderate to severe WML (upper quartile of WML): Change in VF per s.d. decrease in CBF 0.18%, 95% CI: 0.02 to 0.34%. Our findings suggest that cerebral hypoperfusion in the presence of WML may be associated with subcortical brain atrophy.

Detection and characterization of small infarcts in the caudate nucleus on 7 Tesla MRI: The SMART-MR study.

Small infarcts are among the key imaging features of cerebral small vessel disease (CSVD), but remain largely undetected on conventional MRI. We aimed to evaluate (1) imaging criteria for the detection of small infarcts in the caudate nucleus on 7T MRI, (2) intra- and inter-rater agreement, (3) frequency and (4) detection rate on 7T versus 1.5T MRI. In 90 patients (68 ± 8 years) with a history of vascular disease from the SMART-MR study, we defined 7T imaging criteria for cavitated and non-cavitated small infarcts in the caudate nucleus. In a separate set of 23 patients from the SMART study, intra-rater and inter-rater agreement was excellent for presence, number, and individual locations (Kappa's, ICCs, and Dice similarity coefficients ranged from 0.85 to 1.00). In the 90 patients, 21 infarcts (20 cavitated) in 12 patients were detected on 7T (13%) compared to 7 infarcts in 6 patients on 1.5T (7%). In conclusion, we established reproducible imaging criteria for the detection of small infarcts in the caudate nucleus on 7T MRI and showed that 7T MRI allows for a higher detection rate than conventional 1.5T MRI. These imaging criteria can be used in future studies to provide new insights into the pathophysiology of CSVD.

3D MR sialography as a tool to investigate radiation-induced xerostomia: feasibility study.

PURPOSE: To evaluate whether magnetic-resonance (MR) sialography can be used to investigate radiation-induced xerostomia. Preradiotherapy (pre-RT) and postradiotherapy (post-RT) MR sialographic images of the major salivary ducts (parotid and submandibular) were compared. METHODS AND MATERIALS: Magnetic-resonance sialography was performed pre-RT, and 6 weeks and 6 months post-RT on 9 patients with T1-4N0-2M0 naso- or oropharyngeal tumors, on a 1.5-T MR scanner. Patients were positioned in the scanner, using a radiotherapy immobilization mask. Image registration of the MR sialograms pre- and post-RT with each other and with the CT and consequently the dose distribution was performed. A categorical scoring system was used to compare the visibility of ducts pre-RT and post-RT. RESULTS: Good-quality MR sialographic images were obtained, and image registration was successful in all cases. The visibility score of the parotid ducts and submandibular ducts was reduced at 6 weeks post-RT, which means that the full trajectory of the salivary ducts, from the intraglandular space to the mouth cavity, was only partially visualized. For some of the parotid ducts, the visibility score improved at 6 months post-RT, but not for the submandibular ducts. The mean dose for the parotid glands was 35 Gy (1 standard deviation [SD] 3 Gy), and for the submandibular glands it was 62 Gy (SD, 8 Gy). CONCLUSION: Three-dimensional MR sialography is a promising approach for investigating xerostomia, because radiation-induced changes to the saliva content of the ducts can be visualized.

Is microvascular compression of the vestibulocochlear nerve a cause of unilateral hearing loss?

OBJECTIVES: We sought to confirm earlier findings in the literature that microvascular compression of the vestibulocochlear nerve might cause unilateral sensorineural hearing loss. We measured the length and width of the internal auditory canal (IAC) to investigate a possible association between a narrow porus, the presence of an anterior inferior cerebellar artery (AICA) loop, and the development of a microvascular compression syndrome. METHODS: We performed a prospective blinded analysis of 167 magnetic resonance imaging scans of the cerebellopontine angle. The presence of an AICA loop was scored. We analyzed these 167 patients for unilateral sensorineural hearing loss, which was defined as an interaural difference of 20 dB at 1 frequency or 10 dB at 2 or more frequencies. Furthermore, the width and length of the IAC on magnetic resonance imaging were measured. RESULTS: An AICA loop was identified in 94% of the 167 patients. There were 196 type I loops, 106 type II loops, and 14 type III loops. Sixty-six patients had unexplained unilateral hearing loss. There was no association between type II and III vascular loops, the width of the IAC, and unilateral hearing loss (p > .05). CONCLUSIONS: In this study we found no association between the depth of extension of the AICA loop into the IAC and the presence of unilateral hearing loss.

Cardiorespiratory fitness, cognition and brain structure after TIA or minor ischemic stroke.

Background It is not known whether cardiorespiratory fitness is associated with better cognitive performance and brain structure in patients with a TIA or minor ischemic stroke. Aims To examine the association between cardiorespiratory fitness, cognition and brain structure in patients with a TIA and minor stroke. Methods The study population consisted of patients with a TIA or minor stroke with a baseline measurement of the peak oxygen consumption, a MRI scan of brain and neuropsychological assessment. Composite z-scores were calculated for the cognitive domains attention, memory and executive functioning. White matter hyperintensities, microbleeds and lacunes were rated visually. The mean apparent diffusion coefficient was measured in regions of interest in frontal and occipital white matter and in the centrum semiovale as a marker of white matter structure. Normalized brain volumes were estimated by use of Statistical Parametric Mapping. Results In 84 included patients, linear regression analysis adjusted for age, sex and education showed that a higher peak oxygen consumption was associated with higher cognitive z-scores, a larger grey matter volume (B = 0.15 (95% CI 0.05; 0.26)) and a lower mean apparent diffusion coefficient (B = -.004 (95% CI -.007; -.001)). We found no association between the peak oxygen consumption and severe white matter hyperintensities, microbleeds, lacunes and total brain volume. Conclusions These data suggest that cardiorespiratory fitness is associated with better cognitive performance, greater grey matter volume and greater integrity of the white matter in patients with a TIA or minor ischemic stroke. Further prospective trials are necessary to define the effect of cardiorespiratory fitness on cognition and brain structure in patients with TIA or minor stroke.