Frontal Lobe Perfusion Research Articles

Cerebral Blood Flow of the Frontal Lobe in Untreated Children with Trigonocephaly versus Healthy Controls: An Arterial Spin Labeling Study.

Craniofacial surgery is the standard treatment for children with moderate to severe trigonocephaly. The added value of surgery to release restriction of the frontal lobes is unproven, however. In this study, the authors aim to address the hypothesis that the frontal lobe perfusion is not restricted in trigonocephaly patients by investigating cerebral blood flow. Between 2018 and 2020, trigonocephaly patients for whom a surgical correction was considered underwent magnetic resonance imaging brain studies with arterial spin labeling to measure cerebral perfusion. The mean value of cerebral blood flow in the frontal lobe was calculated for each subject and compared to that of healthy controls. Magnetic resonance imaging scans of 36 trigonocephaly patients (median age, 0.5 years; interquartile range, 0.3; 11 female patients) were included and compared to those of 16 controls (median age, 0.83 years; interquartile range, 0.56; 10 female patients). The mean cerebral blood flow values in the frontal lobe of the trigonocephaly patients (73.0 ml/100 g/min; SE, 2.97 ml/100 g/min) were not significantly different in comparison to control values (70.5 ml/100 g/min; SE, 4.45 ml/100 g/min; p = 0.65). The superior, middle, and inferior gyri of the frontal lobe showed no significant differences either. The authors' findings suggest that the frontal lobes of trigonocephaly patients aged less than 18 months have a normal cerebral blood flow before surgery. In addition to the very low prevalence of papilledema or impaired skull growth previously reported, this finding further supports the authors' hypothesis that craniofacial surgery for trigonocephaly is rarely indicated for signs of raised intracranial pressure or restricted perfusion for patients younger than 18 months. Risk, II.

239 IS ORTHOSTATIC HYPOTENSION ASSOCIATED WITH ALTERED CEREBRAL PERFUSION DURING ACTIVE STANDING?

Abstract Background Orthostatic Hypotension (OH) is associated with poor health outcomes in later life including depression, cognitive impairment, frailty and falls. Whilst it is hypothesised that OH compromises cerebral autoregulation leading to hypoperfusion, this has not been robustly demonstrated to date. This study investigated the association between OH and cerebral perfusion during orthostasis using a non-invasive surrogate of cerebral perfusion, Near Infrared Spectroscopy (NIRS). Methods Four hundred and ninety one participants (58% female, median age 65, IQR 38–92) attending a falls and syncope service underwent measurement of beat-to-beat blood pressure (BP) by finometry and real-time frontal lobe perfusion (% TSI: Tissue Saturation Index) by NIRS during the active stand manoeuvre. We examined the association between OH and change in cerebral perfusion (delta TSI) using mixed-effects linear regression, with adjustment for important clinical covariates. Results Nearly two-fifths of the sample (189/491,38.5%) met criteria for OH occurring between 30 and 120 seconds after standing. Using mixed effects linear regression models, we observed a significant relationship between OH and TSI at the same timepoint (β −0.53, −0.59 to −0.46, p < 0.001) which persisted following adjustment for confounders including age, sex, baseline blood pressure, cerebrovascular and cardiovascular disease, depression/anxiety, diabetes, systolic blood pressure, antihypertensives, and antidepressants (β −0.51, −0.58 to −0.44, p < 0.001). Cerebral perfusion levels differed for those with OH compared to those without. Conclusion OH is independently associated with lower frontal lobe cerebral perfusion. This association may indicate disruption to dynamic cerebral autoregulation and explain the significant link between OH and poor health outcomes.

343 Atrial Fibrillation, Orthostatic Hypotension and Cerebral Perfusion – Data from The Irish Longitudinal Study on Ageing

Abstract Background It is thought that cerebral hypoperfusion in Atrial Fibrillation (AF) increases the risk of falls, cognitive impairment, and worse outcome in stroke. This aim of this study is to assess frontal lobe perfusion in response to active stand, and to assess the impact of OH on this association. Methods Data from wave 3 of The Irish Longitudinal Study on Ageing were used, a cohort study of community-dwelling adults aged over 50. Frontal lobe perfusion in response to orthostasis was measured using near infra-red spectroscopy (NIRS), reported as tissue saturation index (TSI%). Orthostatic hypotension (OH) was assessed using beat-to-beat blood pressure measurement. Linear regression assessed whether AF was associated with lower baseline TSI. Mixed effects linear regression assessed whether TSI differed across specific time points – 10, 20, 30, 40 60, 90, and 120 seconds. The analysis were repeated including an interaction with OH to assess the impact of OH on this association. Results There was no difference in baseline TSI in participants with AF compared to those without. Mixed effects models demonstrated lower TSI at 10 seconds in AF (β -0.52; 95% CI -0.88, -0.16; p-value 0.004), at 40 seconds (β -0.40; 95% CI -0.76, -0.04; p-value 0.031) and at 60 seconds (β -0.40; 95% CI --0.76, -0.04; p-value 0.028). Including an interaction with OH found that in isolated AF, TSI was lower at 10 seconds (β -0.62; 95% CI -1.04, -0.19; p-value 0.005). Those with both AF and OH had lower TSI at 40 (β -0.89; 95% CI -1.55, -0.24; p-value 0.007), 60 (β -0.89; 95% CI -1.54, -0.23; p-value 0.008) and 90 (β -0.68; 95% CI -1.33, -0.03; p-value 0.041) seconds. Conclusion There is evidence that frontal lobe perfusion is lower during orthostasis in individuals with AF, and that the presence of OH modifies this association.

Arterial spin labeling perfusion changes of the frontal lobes in children with posterior fossa syndrome.

Posterior fossa syndrome (PFS) is a common complication following the resection of posterior fossa tumors in children. The pathophysiology of PFS remains incompletely elucidated; however, the wide-ranging symptoms of PFS suggest the possibility of widespread cortical dysfunction. In this study, the authors utilized arterial spin labeling (ASL), an MR perfusion modality that provides quantitative measurements of cerebral blood flow without the use of intravenous contrast, to assess cortical blood flow in patients with PFS. A database of medulloblastoma treated at the authors' institution from 2004 to 2016 was retrospectively reviewed, and 14 patients with PFS were identified. Immediate postoperative ASL for patients with PFS and medulloblastoma patients who did not develop PFS were compared. Additionally, in patients with PFS, ASL following the return of speech was compared with immediate postoperative ASL. On immediate postoperative ASL, patients who subsequently developed PFS had statistically significant decreases in right frontal lobe perfusion and a trend toward decreased perfusion in the left frontal lobe compared with controls. Patients with PFS had statistically significant increases in bilateral frontal lobe perfusion after the resolution of symptoms compared with their immediate postoperative imaging findings. ASL perfusion imaging identifies decreased frontal lobe blood flow as a strong physiological correlate of PFS that is consistent with the symptomatology of PFS. This is the first study to demonstrate that decreases in frontal lobe perfusion are present in the immediate postoperative period and resolve with the resolution of symptoms, suggesting a physiological explanation for the transient symptoms of PFS.

The association between frontal lobe perfusion and depressive symptoms in later life.

Deficits in frontal lobe perfusion have been demonstrated in late-life depression; however, studies to date have generally involved small numbers, used neuroimaging rather than bedside testing and have not controlled for important covariates.AimsWe aimed to examine the association between depressive symptoms and frontal lobe perfusion during standing, in a large cohort of community-dwelling older people. Participants aged ≥50 years underwent continuous measurement of orthostatic blood pressure by finometry, and frontal lobe perfusion by near-infrared spectroscopy. Depressive symptoms were assessed by the eight-item Centre for Epidemiological Studies Depression Scale. Real-time frontal lobe cerebral oxygenation was measured by the Portalite System, detecting changes in frontal lobe perfusion and reporting a tissue saturation index score. Almost 8% (209 out of 2616) had clinically significant depressive symptoms. Multilevel models demonstrated a significantly lower tissue saturation index in participants with depressive symptoms at both 60 and 90 s post-stand, with coefficients of -0.43 (95% CI -0.63 to -0.22) and -0.37 (95% CI -0.57 to -0.16), respectively. Controlling for relevant covariates did not significantly attenuate these associations. After addition of systolic blood pressure this association was no longer significant, suggesting lower blood pressure may modify this relationship. This study demonstrates that lower frontal lobe perfusion, related to lower values of baseline systolic blood pressure, is associated with clinically significant depressive symptoms in a cohort of community-dwelling older people. Given the recognised longitudinal association between lower blood pressure and depression in older people, this may represent a potential therapeutic target for prevention of incident depression.Declaration of interestNone.

Dual-phase [18F]florbetapir in frontotemporal dementia

PurposeThe PET tracer [18F]florbetapir is a specific fibrillar amyloid-beta (Aβ) biomarker. During the late scan phase (> 40 min), it provides pathological information about Aβ status. Early scan phase (0–10 min) can provide FDG-‘like’ information. The current investigation tested the feasibility of using florbetapir as a dual-phase biomarker in behavioural variant frontotemporal dementia (bvFTD).MethodsEight bvFTD patients underwent [18F]florbetapir and [18]FDG-PET scans. Additionally, ten healthy controls and ten AD patients underwent florbetapir-PET only. PET data were acquired dynamically for 60-min post-injection. The bvFTD PET data were used to define an optimal time window, representing blood flow-related pseudo-metabolism (‘pseudo-FDG’), of florbetapir data that maximally correlated with the corresponding real FDG SUVR (40–60 min) in a composite neocortical FTD region.ResultsA 2 to 5-min time window post-injection of the florbetapir-PET data provided the largest correlation (Pearson’s r = 0.79, p = 0.02) to the FDG data. The pseudo-FDG images demonstrated strong internal consistency with actual FDG data and were also visually consistent with the bvFTD patients’ hypometabolic profiles. The ability to identify bvFTD from blind visual rating of pseudo-FDG images was consistent with previous reports using FDG data (sensitivity = 75%, specificity = 85%).ConclusionsThis investigation demonstrates that early phase florbetapir uptake shows a reduction of frontal lobe perfusion in bvFTD, similar to metabolic findings with FDG. Thus, dynamic florbetapir scans can serve as a dual-phase biomarker in dementia patients to distinguish FTD from AD and cognitively normal elderly, removing the need for a separate FDG-PET scan in challenging dementia cases.

A change of cerebral perfusion of patients with chronic neuropsychological impairments before and after a daytreatment group rehabilitation

The objective of this study is to evaluate a change of cerebral perfusion of patients with chronic neuropsychological impairments (NPIs) before and after a daytreatment group rehabilitation, using 99mTc-ethylcysteinate dimer single photon emission computed tomography (Tc-ECD SPECT) and its novel analytic software. Eight patients were examined in the chronic period of acquired brain injury with NPIs. All patients received a daytreatment group rehabilitation (3 hours once per week for half a year). The group rehabilitation included patient and family education, mindfulness exercise and group discussion exercise. The examinations of patients were performed before and after the group rehabilitation, and it included the assessment of neurological deficit, cognitive functions, and Tc-ECD SPECT. Statistical parametric mapping (SPM) was applied to each Tc-ECD SPECT image, for spatial pre-processing and analysis and to determine the quantitative perfusion change before and after the group intervention (paired t -test, uncorrected, P < 0.001). SPM analysis of Tc-ECD SPECT showed the significant improvement of cerebral perfusion in right frontal lobe (Brodmann area 10) before and after the group rehabilitation. There was no significant improvement in cognitive functions as assessed with structured batteries for NPIs, while there was a trend towards the improvement behaviorally (for example, 6 patients had been able to rework after the intervention). Using Tc-ECD SPECT and its novel analytic software, we identified specific lesions with improvement of cerebral perfusion before and after the daytreatment group rehabilitation for NPIs. It might relate with social reintegration of patient with NPIs.

Microvascular and large vein abnormalities in young patients after mild head trauma and associated fatigue: A brain SPECT evaluation and posture dependence modeling

ObjectiveMRI and CT scans are usually normal in mild traumatic brain injury (mTBI) although 15–20% of such patients suffer for months from fatigue, headache, anxiety, sleep and other disorders. mTBI is suspected to be a cerebrovascular injury, similar to moderate and severe TBI. Brain SPECT is more sensitive and shows perfusion abnormalities immediately after mTBI. This work explores the perfusion abnormalities for young patients suffering from fatigue several months after mTBI. Patients and methodsTwelve mTBI patients (age:8–36 yr, 4 male) with no history of fatigue prior to trauma were prospectively studied following onset of fatigue 6–12 months after mTBI utilizing 99 m-Tc ECD brain SPECT with early and delayed radiotracer imaging. ResultsThe perfusion pattern in the mTBI + fatigue group included left hemispheric deficits in frontal lobes (early phase: 15.2 ± 4.2%, delayed phase: 9.9 ± 2.2%) and medial temporal lobes (early phase 11.2 ± 3.7%, delayed phase: 9.0 ± 2.3%). Seven patients additionally showed excess tracer accumulation in the parenchyma surrounding internal jugular bulb inferior to temporal lobe. This was modeled as due to increased cellular permeability from TBI induced oxidative stress affecting endothelial tight junctions and consequent tracer leakage across jugular bulbs. Prolonged posture changes from erect to supine position during imaging increase jugular cross-sectional area and venous wall pressure as has been observed in other disease processes and seem to be responsible for tracer leakage from jugular bulbs in our study. ConclusionThis work supports an oxidative stress and BBB disruption model for mTBI. The frontal and temporal lobe perfusion deficits are attributed to anatomical vulnerabilities of these lobes. During a mild TBI both of these lobes are susceptible to grazing impacts with underlying bony ridges. We propose a relation between mTBI and fatigue arising from oxidative stress in mTBI affecting ATP generation and altering endothelial homeostasis for both micro-and-large vasculatures. The tracer leakage observed around jugular veins is due to posture induced changes in venous cross-sections and wall pressure as well as from compromised endothelium post TBI induced oxidative stress.

Frontal lobe executive dysfunction and cerebral perfusion study in alcohol dependence syndrome.

Background:Long-term alcohol use leading to frontal lobe impairment has been a cause of concern for many decades. However, there are very few studies from India of evaluation of frontal lobe executive dysfunction among alcoholics. Hence, this study was undertaken to evaluate the frontal executive dysfunction using Wisconsin Card Sorting Test (WCST) and perfusion deficits by Single-Photon Emission Computerized Tomography (SPECT) among alcohol-dependent patients.Aim:The aim of this study is to evaluate the frontal executive dysfunction using WCST and frontal lobe perfusion deficits by SPECT among alcohol-dependent patients.Materials and Methods:This was a cross-sectional study involving 20 alcohol dependence syndrome patients in a tertiary care center. After ethical clearance and informed consent, all were evaluated using WCST and SPECT.Results:About 45% patients had impairment on WCST, and it was related to the duration of drinking. About 55% showed reduced frontal lobe perfusion on SPECT scan and they had a long duration of drinking compared to controls. Among the patients showing impairment on WCST subscores, more than 50% had reduced frontal lobe perfusion on SPECT.Conclusion:This study not only confirmed the executive function impairment and frontal lobe perfusion deficits in alcohol-dependent patients but also showed a concomitant presence of both in patients with chronic alcohol abuse.

Brain Perfusion Scintigraphy in Evaluation of Pathogenesis of Fatigue in Patients with Primary Biliary Cholangitis (PBC) – A Pilot Study

Primary biliary cholangitis (PBC) is an autoimmune cholestatic liver disease characterized by a breakdown of immune tolerance to mitochondrial and nuclear antigens, causing injury to the biliary epithelial cells. Fatigue is the commonest reported symptom in PBC and has a negative impact on patients' perceived quality of life, often through social isolation. It is unrelated to the severity of liver disease and appears unresponsive to current therapies, including ursodeoxycholic acid and transplantation. Fatigue in PBC is complex, with numerous associated peripheral and central nervous system (CNS) features. Initially, cholestasis causes degenerative CNS change affecting areas of the brain regulating autonomic dysfunction and sleep, and these changes lead directly to some manifestations of fatigue and the associated cognitive impairment. The aim of the study was to examine global cerebral blood flow with brain perfusion scintigraphy SPECT in well-defined group of PBC Caucasian patients with verbally reported fatigue. Twenty consecutive PBC female patients (median age 58.9, ranges 38-80; 4 cirrhotic) with mean duration of the disease 3.3 years, were prospectively enrolled into the study. Fatigue Impact Scale (FIS) questionnaire was administered to every patients at the moment of brain examination. Brain perfusion scintigraphy SPECT was performed after intravenous injection of 760-800 MBq of technetium99m labeled exametazime (99mTc –HMPAO). Then patients were examined using double head gamma camera system, and data were analyzed with dedicated nuclear medicine software. In analyzed cohort the median FIS score was 70.5 points (ranges 21-160), which was higher than previously reported. There were no correlation between age of patients at the SPECT/FIS examination, duration of the disease, the presence of liver cirrhosis, Mayo Risk Score, and FIS domains: Cognitive, Physical and Social, as well as with brain blood flow. However, positive correlation between Cognitive dimension of FIS measure and right frontal lobe perfusion impairment assessed with SPECT technic (p<0.05) was found. The results of this study showed that right lobe perfusion impairment might impact brain function in PBC. Cognitive dimension was stage-independent symptom in analyzed cohort, and cognitive impairment might be, in turn, associated with functional brain lesion.

Frontotemporal Lobar Degeneration-Modified Clinical Dementia Rating (FTLD-CDR) Scale and Frontotemporal Dementia Rating Scale (FRS) Correlation With Regional Brain Perfusion in a Series of FTLD Patients.

Severity assessment scales for frontotemporal lobar degeneration (FTLD) have been recently introduced. In the present study, the authors examined whether the FTLD-modified Clinical Dementia Rating (FTLD-CDR) scale and the Frontotemporal Dementia Rating Scale (FRS) correlated with regional brain perfusion in Greek FTLD patients. A total of 47 behavioral variant frontotemporal dementia (bvFTD) patients and 33 primary progressive aphasia (PPA) patients were assessed for demographic data, cognitive reserve (CR), and severity of dementia and underwent brain single-photon emission computed tomography. Both scales were valid in the bvFTD group, predicting frontal lobe perfusion. In the PPA group, both scales were found to predict temporal hypoperfusion only after accounting for CR, which could imply a potential role for reserve in PPA patients.

Acetazolamide Stress SPECT Test on Cerebral Blood Flow in Patients with Depressive Disorder

The regional cerebral blood flow (rCBF) and the cerebral vasoreactivity of the patients with depressive disorder were observed by SPECT and acetazolamide stress SPECT test respectively. Eighteen unmedicated depressed patients and nineteen healthy control subjects were included. Baseline SPECT was performed in both patients and control subjects. Acetazolamide stress SPECT test was performed two days later in patients two hours after taking 2g acetazolamide orally. It was found that there was significant difference between the untreated depressed patients and the controls, because there was relatively reduced perfusion in frontal lobe, temporal lobe, left parietal lobe and right basal ganglia in depressed patients. After acetazolamide stress SPECT test, the perfusion of decreased regions in baseline step was increased. No potential ischemic lesion was found. The perfusion of some specific regions of the depressed patients decreased. Acetazolamide stress SPECT test could not reveal silent brain ischemia in the depressed patients. The perfusion of decreased regions in the baseline imaging was increased in acetazolamide stress SPECT test.

Encephaloduromyosynangiosis (EDMS) on a Pediatric Patient with Cerebral Proliferative Angiopathy

Cerebral proliferative angiopathy (CPA) is a rare cerebral vascular lesion characterized by diffuse vascular abnormalities with intermingled normal brain parenchyma. Cerebral proliferative angiopathy has a complex clinical presentation, and many patients present with ischemic symptoms. We described a case of a 6 year old boy presenting with transient dizziness with weakness of left limbs. MRI showed the presence of a diffusely dilated extensive vascular lesion mainly located in the corpus callosum, right frontal and temporal lobes. Digital subtraction angiography (DSA) revealed a large hypervascular lesion with a diffuse arterial supply. 99mTc-ECD SPECT cerebral blood flow perfusion image revealed decreased perfusion in right frontal and parietal lobe. A surgical procedure of encephaloduromyosynangiosis (EDMS) was performed on the patient, and the patient exhibited disappearance of TIAs during the follow-up period. There is no consensus on treatment of cerebral proliferative angiopathy, but the hemodynamic characteristics of CPA were more similar to moyamoya disease in the PWI-MR study. Furthermore, we speculated that increased regional cerebral blood flow perfusion may relieve clinical symptoms and improve prognosis of patient with CPA. Therefore, we performed encephaloduromyosynangiosis (EDMS) on this pediatric CPA patient with ischemic symptoms. 99mTc-ECD SPECT obtained 6 months after operation showed significant improvement of right frontal and parietal blood perfusion. MR perfusion at follow-up period demonstrated the range and blood flow of vascular lesion decreased significantly compared with preoperative MR perfusion. Follow-up angiography studies showed well compensation by profound neovascularization through the superficial temporal artery, and vascular malformation disappeared around the region supplied from the ECA. EDMS procedure may be a reasonable and effective treatment for patients with ischemia associated with CPA.

The adverse effects of reduced cerebral perfusion on cognition and brain structure in older adults with cardiovascular disease

BackgroundIt is well established that aging and vascular processes interact to disrupt cerebral hemodynamics in older adults. However, the independent effects of cerebral perfusion on neurocognitive function among older adults remain poorly understood. We examined the associations among cerebral perfusion, cognitive function, and brain structure in older adults with varying degrees of vascular disease using perfusion magnetic resonance imaging (MRI) arterial spin labeling (ASL).Materials and methods52 older adults underwent neuroimaging and were administered the Mini Mental State Examination (MMSE), the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and measures of attention/executive function. ASL and T1-weighted MRI were used to quantify total brain perfusion, total brain volume (TBV), and cortical thickness.ResultsRegression analyses showed reduced total brain perfusion was associated with poorer performance on the MMSE, RBANS total index, immediate and delayed memory composites, and Trail Making Test B. Reduced frontal lobe perfusion was associated with worse executive and memory function. A similar pattern emerged between temporal lobe perfusion and immediate memory. Regression analyses revealed that decreased total brain perfusion was associated with smaller TBV and mean cortical thickness. Regional effects of reduced total cerebral perfusion were found on temporal and parietal lobe volumes and frontal and temporal cortical thickness.DiscussionReduced cerebral perfusion is independently associated with poorer cognition, smaller TBV, and reduced cortical thickness in older adults.ConclusionProspective studies are needed to clarify patterns of cognitive decline and brain atrophy associated with cerebral hypoperfusion.

Exercise Periodic Breathing Impairs Functional Capacity by Reducing the Ventilatory‐Hemodynamic Efficiency in Patients with Heart Failure

This investigation elucidated how exercise periodic breathing (EPB) influences functional capacity by modulating the ventilatory‐hemodynamic efficiency in patients with heart failure (HF). Ninety‐eight HF patients with (n=45) or without (n=43) EPB performed an incremental exercise test using a bicycle ergometer. A noninvasive bio‐reactance device was applied to measure cardiac hemodynamics, and a near‐infrared spectroscopy was employed to assess perfusion in frontal cerebral lobe and vastus lateralis muscle. Compared to non‐EPB counterparts, the patients with EPB revealed (i) smaller VO2peak and oxygen uptake efficiency slopes (OUES) and greater VE‐VO2 slopes; (ii) less cardiac output (QH) and perfusions in the frontal cerebral lobe (QC) and vastus lateralis muscle (QM) during exercise; and (iii) lower the score of the Short Form‐36 physical component and higher the score of the Minnesota Living with Heart Failure questionnaire. Peak QH, QC, and QM levels were directly related the OUES and VO2peak, and inversely related to the VE‐VCO2 slope. In multivariate analysis, the VE‐VCO2 slope was an effect modifier, which modulated the correlation between the Short Form‐36 physical score and central/peripheral hemodynamics. Therefore we conclude that EPB may reduce the ventilatory‐hemodynamic efficiency during exercise, thereby impairing functional capacity in patients with HF.

Correlation between cognitive impairment and cerebral hemodynamic disturbances on perfusion magnetic resonance imaging in European adults with moyamoya disease

Although cognitive impairment has been reported in adults with moyamoya disease (MMD), its relationship with cerebral hemodynamic disturbances has not been investigated. The aims of the present study were to confirm the presence of dysexecutive cognitive syndrome (DCS) in adults with MMD and to explore the relationship of DCS with frontal lobe perfusion as measured by perfusion MR imaging. Cerebral blood volume (CBV) ratio and mean transit time delay were measured in frontal and temporoparietal regions using the cerebellum as a reference region in 10 European adults with MMD. In addition, the authors calculated the cerebrovascular reserve (CVR) using the CBV ratio and the acetazolamide challenge. All patients underwent a standardized neuropsychological assessment test battery. The authors defined DCS as an impairment shown on 3 tests or more of executive function. The authors found DCS in 6 patients. The frontal CVR was lower in patients with DCS than in patients without DCS (mean ± SD: -13.5 ± 13.2% and 20.3 ± 21.3%; p = 0.019, Mann-Whitney U-test). Other parameters of frontal perfusion and temporoparietal CVR were not correlated with DCS. The authors' findings suggest that DCS is common in European adults with MMD and may be related to frontal perfusion impairment.

Gray matter perfusion correlates with disease severity in ALS

The goal of this study is to determine if regional brain perfusion, as measured by arterial spin labeling (ASL) MRI, is correlated with clinical measures of amyotrophic lateral sclerosis (ALS) disease severity. The presence of such a relationship would indicate a possible role for ASL perfusion as a marker of disease severity and upper motor neuron involvement in ALS. Disease severity was assessed in 16 subjects with ALS (age 54 +/- 11) using the Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) and the pulmonary function measure, forced vital capacity (FVC). Upper motor neuron involvement was assessed by testing rapid tapping of the fingers and feet. Magnetic resonance perfusion images were coregistered with structural T1-weighted MRI, corrected for partial volume effects using the structural images and normalized to a study-specific atlas. Correlations between perfusion and ALS disease severity were analyzed, using statistical parametric mapping, and including age as a factor. Analyses were adjusted for multiple clusters. ALS severity, as measured by the ALSFRS and FVC, was correlated with gray matter perfusion. This correlation was predominantly observed in the hemisphere contralateral to the more affected limbs. ALSFRS scores correlated with perfusion in the contralateral frontal and parietal lobe (p < 0.001) and ipsilateral frontal lobe (p < 0.02). FVC scores correlated with gray matter perfusion in contralateral frontal lobe (p < 0.001). Upper motor neuron involvement, as measured by rapid finger tapping, correlated bilaterally with perfusion in the middle cingulate gyrus (p < 0.001). Amyotrophic lateral sclerosis (ALS) severity is correlated with brain perfusion as measured by arterial spin labeling (ASL) perfusion. This correlation appears to be independent of brain atrophy. ASL perfusion may be a useful tool for monitoring disease progression and assessing treatment effects in ALS.

Improvement of neurocognitive function after protected carotid artery stenting

To investigate the effect of protected carotid artery stenting on neurocognitive function with particular consideration of the angiographic filling of the ipsilateral anterior cerebral artery (ACA). An improved inflow to the supply area of the anterior cerebral artery after revascularisation of severe carotid artery stenosis may beneficially affect frontal lobe cognitive functions. We prospectively included 71 consecutive patients who underwent carotid artery stenting (CAS) due to high grade carotid artery stenosis. Intracranial angiograms and filling status of the ACA pre- and post-stenting were analyzed and a battery of 5 selected neuropsychological tests for frontal lobe function were applied prior to and 6 months after CAS. Patients with improvement in at least two tests were defined as having improved neurocognitive function. Compared to baseline, we found a significant improvement of the Trail-Making Test A (median 6% improved change-score; P = 0.01), the test of supermarket items showed a trend towards significant improvement (median 3.7% improved change-score; P = 0.09). In 32 patients (45%) an improvement of at least 2 neurocognitive tests was observed. Neuropsychological improvement was found more frequently in patients with a contrasted ipsilateral ACA after CAS (88%, 95% CI 77 to 99) compared to patients without angiographic filling of the ipsilateral ACA post CAS (13%, 95% CI 1 to 25), respectively (P < 0.01). Carotid artery stenting improves neurocognitive function in a considerable proportion of patients. A contrasted ipsilateral anterior cerebral artery after CAS is associated with improved neurocognitive function, presumably due to amelioration of frontal lobe perfusion.

Hypoperfusion in frontotemporal dementia and Alzheimer disease by arterial spin labeling MRI

To test if arterial spin labeling (ASL) MRI could detect a pattern of hypoperfusion in frontotemporal dementia (FTD) vs cognitively normal (CN) control subjects; to determine the regional difference of perfusion between FTD and Alzheimer disease (AD); and to determine whether hypoperfusion in FTD correlates with cognitive impairment. We included 21 patients with FTD, 24 patients with AD, and 25 CN subjects in this cross-sectional MRI study. All subjects had MRI scans including T1-weighted structural images and ASL-MR images. ASL-MRI detected a pattern of hypoperfusion in right frontal regions in patients with FTD vs CN subjects, similar to PET and SPECT. FTD had higher perfusion than AD in the parietal regions and posterior cingulate. Frontal hypoperfusion in FTD correlated with deficits in judgment and problem solving. Adding frontal perfusion to gray matter (GM) atrophy significantly improved the classification of FTD from normal aging to 74%, and adding parietal perfusion to GM atrophy significantly improved the classification of FTD from AD to 75%. Combining frontal and parietal lobe perfusion further improved the classification of FTD from AD to 87%. Frontotemporal dementia and Alzheimer disease display different spatial distributions of hypoperfusion on arterial spin labeling MRI. With further development and evaluation, arterial spin labeling MRI could contribute to the differential diagnosis between frontotemporal dementia and Alzheimer disease.

Cognition, behavior and the frontal lobes

Our knowledge of how the brain functions has markedly improved in recent years, but this improvement has largely been constrained to simpler levels of processing such as those involved in sensory or motor systems. In contrast, the neural bases of higher functions such as consciousness, will, long-term planning, complex problem- solving, etc., are still under investigation, although everyone agrees that the frontal lobes (FL) play an important role in such processes. The importance of understanding these neural bases of higher functions becomes even more evident in the study of aging, since a decrease of frontal lobe perfusion is reported during aging, and because this age-related frontal lobe dysfunction has been proposed to explain part of the cognitive disorders (attention disorders, decreased mental flexibility and abstraction) and behavioral changes (mainly apathy or indifference) associated with aging.