Effect of carotid artery stenting on cerebral blood flow: evaluation of hemodynamic changes using arterial spin labeling

Introduction

The purpose of this work was to quantitatively evaluate the hemodynamic changes after carotid artery stenting (CAS) by measuring cerebral blood flow (CBF) using arterial spin labeling (ASL).

Methods

Twenty sets of pre- and postprocedural CBF maps were acquired using ASL in patients who underwent CAS. Vascular territory- and anatomical structure-based regions of interest were applied to the CBF maps. Relative CBF (rCBF) was calculated by adjusting ipsilateral CBF with contralateral CBF. To assess the changes in rCBF after CAS (ΔrCBF), we calculated the following difference: $ \Delta\mathrm{rCBF}=\mathrm{rCB}{{\mathrm{F}}_{\mathrm{postprocedural}}}-\mathrm{rCB}{{\mathrm{F}}_{\mathrm{preprocedural}}} $ .

Results

Postprocedural CBFs were significantly higher than preprocedural CBFs for internal carotid artery and middle cerebral artery territories (P?<?0.05 in both). Postprocedural rCBFs were also significantly higher than preprocedural rCBFs for internal carotid artery and middle cerebral artery territories (P?<?0.05 in both). Significant correlations were observed between preprocedural rCBF and ΔrCBF for the internal carotid artery and middle cerebral artery territories (r?=??0.7211, P?=?0.0003 and r?=??0.6427, P?=?0.0022, respectively). Areas in which the ΔrCBF values were >5.00 ml?100 g^?1 min^?1 were the precentral, postcentral, middle frontal, middle temporal (caudal), superior parietal, and angular gyri.

Conclusions

ASL has potential as a noninvasive imaging tool for the quantitative evaluation of hemodynamic changes after CAS. CAS improves cerebral perfusion in patients with carotid artery stenosis, and patients with greater perfusion deficits prior to CAS have greater improvement in perfusion after CAS. In addition, eloquent areas show the greatest improvement in perfusion.     

Karotisstents – eine Standortbestimmung

Clinical/methodical issue

Therapy of carotid stenosis should be based on an accurate assessment of the stenosis and a differentiation between symptomatic and asymptomatic patients.

Standard radiological methods

According to current guidelines carotid artery stenting (CAS) can be considered as an established therapeutic alternative to carotid endarterectomy (CEA).

Methodical innovations

For the therapy of carotid stenosis CAS has become established as a minimally invasive alternative to CEA because the complication rate has been reduced due to growing experience, technical innovations and external quality assessment.

Performance

The CAS procedure should be performed in centers with documented complication rates of <?3?% for asymptomatic and <?6?% for symptomatic stenoses.

Achievements

Overall there are no significant differences between CAS and CEA in the treatment of carotid stenosis concerning the secondary prophylactic effect.

Practical recommendations

Ideally an interdisciplinary approach should be chosen for the therapy regime. Revascularization of asymptomatic stenoses should be considered critically as these patients might profit from optimized conservative medicinal therapy.     

Calcium at the carotid siphon as an indicator of internal carotid artery stenosis

Objectives

Carotid siphon calcification is often visible on unenhanced head CT (UCT), but the relation to proximal carotid artery stenosis (CAS) is unclear. We investigated the association of carotid siphon calcification with the presence of CAS.

Methods

This IRB-waived retrospective study included 160 consecutive patients suspected of stroke (age 64?±?14 years, 63 female) who underwent head UCT and CTA of the head and neck. CAS was rated on CTA as not present or present with non-significant (<50 %), moderate (50–69 %) or significant (≥70 %) stenosis. Presence, shape (on UCT) and volume (on CTA) of carotid siphon calcifications were related to CAS.

Results

Carotid siphon calcification was absent in 41 % of patients and bilateral in 94 % of those with calcifications. Presence, shape and volume of calcification resulted in odds ratios for having significant CAS of 10.1, 3.9 and 8.4, with 95 % CIs of 1.3–79.6, 1.1–14.1 and 2.6–26.8, respectively. Corresponding NPVs were 0.98, 0.98 and 0.96, while PPVs were 0.14, 0.07 and 0.29, respectively.

Conclusion

Absence of calcification in the carotid artery siphon on UCT has high negative predictive value for carotid artery stenosis in patients with suspected stroke. However, siphon calcification is not a reliable indicator of significant carotid artery stenosis.

Key Points

? Many stroke patients do not have calcification in the carotid artery siphon. ? Carotid stenosis ≥50?% is unlikely in stroke patients without siphon calcification. ? Carotid siphon calcium is a poor indicator of significant carotid artery stenosis.     

Magnetic resonance plaque imaging to predict the occurrence of the slow-flow phenomenon in carotid artery stenting procedures

Introduction

The purpose is to investigate the feasibility of magnetic resonance (MR) plaque imaging in predicting the arterial flow impairment (slow-flow phenomenon) during carotid artery stenting (CAS) using a filter-type protection device.

Methods

Thirty-one carotid artery stenotic lesions in 30 patients (28 men and two women; mean age, 71.8 years) were evaluated by MR plaque imaging with black blood T1- and T2-weighted and time-of-flight sequences before CAS. Main plaque components were classified as vulnerable (intraplaque hemorrhage and lipid-rich/necrotic core) or stable (fibrous tissue and dense calcification) from the signal pattern. The plaque classification was statistically compared with the occurrence of slow-flow phenomenon.

Results

The slow-flow phenomenon was observed in ten CAS procedures (five flow arrests and five flow reductions). Flow arrests consisted of four vulnerable and one stable plaque, and flow reductions consisted of four vulnerable and one stable plaque. The slow-flow phenomenon occurred significantly (P?<?0.01) more frequently in patients with vulnerable plaque.

Conclusions

Vulnerable carotid plaques have a significantly higher risk of slow-flow phenomenon than stable plaques. The occurrence of the slow-flow phenomenon can be predicted by MR plaque imaging before CAS.     

Factors affecting brain structure in men with HIV disease in the post-HAART era

Introduction

The purpose of this study was to characterize brain volumetric differences in HIV seropositive and seronegative men and to determine effects of age, cardiovascular risk, and HIV infection on structural integrity.

Methods

Magnetic resonance imaging was used to acquire high-resolution neuroanatomic data in 160 men aged 50?years and over, including 84 HIV seropositive and 76 seronegative controls. Voxel-based morphometry was used to derive volumetric measurements at the level of the individual voxel. Data from a detailed neuropsychological test battery were recombined into four summary scores representing psychomotor speed, visual memory, verbal memory, and verbal fluency.

Results

Both age and HIV status had a significant effect on both gray matter (GM) and white matter (WM) volume. The age-related GM atrophy was primarily in the superior temporal and inferior frontal regions; the HIV-related GM loss included the posterior and inferior temporal lobes, the parietal lobes, and the cerebellum. Among all subjects, the performance on neuropsychological tests, as indexed by a summary variable, was related to the volume of both the GM and WM. Contrary to our predictions, the CVD variables were not linked to brain volume in statistically adjusted models.

Conclusion

In the post-HAART era, having HIV infection is still linked to atrophy in both GM and WM. Secondly, advancing age, even in this relatively young cohort, is also linked to changes in GM and WM volume. Thirdly, CNS structural integrity is associated with overall cognitive functions, regardless of the HIV infection status of the study volunteers.     

Carotid artery stenting in difficult aortic arch anatomy with or without a new dedicated guiding catheter: preliminary experience

Objectives

To evaluate carotid artery stenting (CAS) procedures with or without a new dedicated guiding catheter in anatomically challenging aortic arches in our experience.

Methods

We retrospectively reviewed 172 procedures of CAS performed from December 2006 to October 2011 in 159 consecutive patients (100 men, mean age 78 years): 15 patients had type III aortic arch, 13 had a bovine aortic arch, 6 had an acute angle at the origin of the left common carotid artery from the aortic arch, 2 had type III aortic arch with bovine aortic arch, and 1 had a bicarotid trunk with an aberrant right subclavian artery. In this group of difficult anatomy (37 cases), CAS was performed with (13 cases) or without (24 cases) a new dedicated guiding catheter.

Results

Mean time of fluoroscopy (16 min vs. 18 min, P?<?0.01), mean total procedural time (68 min vs. 83 min, P?<?0.001), technical failure (0/13 vs. 3/24 cases, P?=?0.01), clinical failure (0/13 vs. 4/21 cases, P?=?0.02) and local complications (0/13 vs. 2/24 cases, P?<?0.0001) were significantly lesser in the dedicated guiding catheter group.

Conclusions

The new dedicated guiding catheter may be more effective and less risky for CAS in anatomically challenging aortic arches.

Key Points

? Complex anatomy of the aortic arch is not rare ? Endovascular carotid artery stenting (CAS) is more difficult when the anatomy is complex ? A new dedicated guiding catheter may help CAS when the arch anatomy is complex ? The new dedicated guiding catheter may be less risky in complex arches     

Fragmentation of calcified plaque after carotid artery stenting in heavily calcified circumferential stenosis

Introduction

We assessed the morphological change of calcified plaque after carotid artery stenting (CAS) in vessels with heavily calcified circumferential lesions and discuss the possible mechanisms of stent expansion in these lesions.

Methods

We performed 18 CAS procedures in 16 patients with severe carotid artery stenosis accompanied by plaque calcification involving more than 75% of the vessel circumference. All patients underwent multidetector-row computed tomography (MDCT) to evaluate lesion calcification before and within 3 months after intervention. The angiographic outcome immediately after CAS and follow-up angiographs obtained 6 months post-CAS were examined.

Results

The preoperative mean arc of the calcifications was 320.1?±?24.5° (range 278–360°). In all lesions, CAS procedures were successfully carried out; excellent dilation with residual stenosis ≤30% was achieved in all lesions. Post-CAS MDCT demonstrated multiple fragmentations of the calcifications in 17 of 18 lesions (94.4%), but only cracks in the calcified plaque without fragmentation in one (5.6%). Angiographic study performed approximately 6 months post-CAS detected severe restenosis in one lesion (5.6%) without fragmentation of calcified plaque.

Conclusions

Excellent stent expansion may be achieved and maintained in heavily calcified circumferential carotid lesions by disruption and fragmentation of the calcified plaques.     

Disrupted white matter structure underlies cognitive deficit in hypertensive patients

Objectives

Hypertension is considered a risk factor of cognitive impairments and could result in white matter changes. Current studies on hypertension-related white matter (WM) changes focus only on regional changes, and the information about global changes in WM structure network is limited.

Methods

We assessed the cognitive function in 39 hypertensive patients and 37 healthy controls with a battery of neuropsychological tests. The WM structural networks were constructed by utilizing diffusion tensor tractography and calculated topological properties of the networks using a graph theoretical method. The direct and indirect correlations among cognitive impairments, brain WM network disruptions and hypertension were analyzed with structural equation modelling (SEM).

Results

Hypertensive patients showed deficits in executive function, memory and attention compared with controls. An aberrant connectivity of WM networks was found in the hypertensive patients (P _Eglob?=?0.005, P _Lp?=?0.005), especially in the frontal and parietal regions. Importantly, SEM analysis showed that the decline of executive function resulted from aberrant WM networks in hypertensive patients (p?=?0.3788, CFI?=?0.99).

Conclusions

These results suggest that the cognitive decline in hypertensive patients was due to frontal and parietal WM disconnections. Our findings highlight the importance of brain protection in hypertension patients.

Key points

? Hypertension has a negative effect on the performance of the cognitive domains ? Reduced efficiencies of white matter networks were shown in hypertension ? Disrupted white matter networks are responsible for poor cognitive function in hypertension

     

Novel 3D-CT evaluation of carotid stent volume: greater chronological expansion of stents in patients with vulnerable plaques

Introduction

Although self-expanding carotid stents may dilate gradually, the degrees of residual stenosis have been quantified by the NASCET criteria, which is too simple to reflect the configuration of the stented artery. We measured the volumes of the stent lumens chronologically by 3D-CT in patients after carotid artery stenting (CAS), and analyzed the correlations between the volume change and medical factors.

Methods

Fourteen patients with carotid artery stenosis were treated using self-expanding, open-cell stents. All patients underwent preoperative plaque MRI (magnetization-prepared rapid acquisition gradient-echo, MPRAGE) and chronological 3D-CT examinations of their stents immediately after their placement and 1 day, 1 week, and 1 month after the procedure. The volume of the stent lumen was measured using a 3D workstation. The correlations between stent volume and various factors including the presence of underlying diseases, plaque characteristics, and the results of the CAS procedure were analyzed.

Results

Stent volume gradually increased in each case and had increased by 1.04–1.55 (mean, 1.25)-fold at 1 postoperative month. The presence of underlying medical diseases, plaque length, the degree of residual stenosis immediately after CAS, and plaque calcification did not have an impact on the change in stent volume. On the other hand, the stent volume increase was significantly larger in the patients with vulnerable plaques that demonstrated high MPRAGE signal intensity (P?<?0.05).

Conclusions

A 3D-CT examination is useful for precisely measuring stent volume. Self-expanding stents in carotid arteries containing vulnerable plaques expand significantly more than those without such plaques in a follow-up period.     

Correlation between neuropsychological tests and hypoperfusion in MCI patients: anatomical labeling using xjView and Talairach Daemon Software

Purpose

Statistical analysis of brain perfusion SPECT images has shown mild to severe abnormalities, consistent with cortical dysfunctions in the brain. Recently, functional brain imaging such as fMRI, PET and SPECT is increasingly used for diagnosis of MCI. In this study, we calculate the correlation with perfusion of brain SPECT and neuropsychological test scores of patients by SPM analysis to evaluate the relationship with cerebral hypoperfusion and cognitive dysfunction in MCI patients. Anatomical labeling was performed automatically using the Talairach Daemon (TD) and xjView.

Methods

Ninety-three patients (mean age 67.2?±?7.42?years; 59 women and 34 men) with MCI were selected and examined by the comprehensive neuropsychological test. Tc-99m-HMPAO brain SPECT images were acquired on the patients using a two-head gamma camera. We analyzed the brain image of MCI patients by SPM8 software, and observed the anatomical correlated region, between the neuropsychological tests and cerebral hypoperfusion. The SPM8 tool provided correlation between neuropsychological score and brain perfusion by simple regression method. The neuropsychological test included attention, language function, visuospatial function, memory, frontal executive function, depression score and general cognitive function.

Results

Percentage of voxels with correlated area to the whole brain was calculated and the values by Rey complex figure test (CFT) copy score, MMSE score, Seoul verbal learning test (SVLT) immediate recall score and Rey CFT delayed recall score were 15.3, 12.33, 10.59 and 8.45?%, respectively. Rey CFT copy score was correlated with perfusion in the left middle temporal gyrus (BA 21), right inferior frontal gyrus (BA 45), right lingual gyrus, left lingual gyrus (BA 18), right postcentral gyrus (BA 40), right cingulate gyrus (BA 31) and left thalamus (pulvinar) with p?<?0.01 FDR. The correlation related to MMSE included left parahippocampal gyrus, right fusiform gyrus and right middle frontal gyrus (BA 46). SVLT immediate recall score was correlated with left superior temporal gyrus and Rey CFT delayed recall score was correlated with left inferior frontal gyrus (BA 47), right inferior frontal gyrus, and left lentiform nucleus. Visuospatial and general cognitive dysfunctions in the patients with MCI were most correlated with cerebral hypoperfusion.

Conclusions

Rey CFT copy and MMSE scores were more strongly correlated with blood perfusion of the brain than with other neuropsychological test scores. xjView was a useful tool to find out the anatomical name of the selected voxel or clusters and to display the cluster??s anatomical information and list all cluster information and could be used instead of TD Client.     

Decline in prefrontal catecholamine synthesis explains age-related changes in cognitive speed beyond regional grey matter atrophy

Purpose

Age-related decline in cognitive speed has been associated with prefrontal dopamine D1 receptor availability, but the contribution of presynaptic dopamine and noradrenaline innervation to age-related changes in cognition is unknown.

Methods

In a group of 16 healthy participants aged 22–61?years, we used PET and the radioligand FDOPA to measure catecholamine synthesis capacity (K _in ^app; millilitres per gram per minute) and the digit symbol substitution test to measure cognitive speed, a component of fluid IQ.

Results

Cognitive speed was associated with the magnitude of K _in ^app in the prefrontal cortex (p?p?=?0.003) and FDOPA K _in ^app (p?K _in ^app remained significant beyond the effects of age (p?=?0.047). MR-based segmentation revealed that these age-related declines were not attributable to age-related alterations in grey matter density.

Conclusion

Our findings indicate that age-related changes in the capacity of the prefrontal cortex to synthesize catecholamines, irrespective of cortical atrophy, may underlie age-related decline in cognitive speed.     

Brain perfusion correlates of cognitive and nigrostriatal functions in de novo Parkinson��s disease

Purpose

Subtle cognitive impairment is recognized in the first stages of Parkinson??s disease (PD), including executive, memory and visuospatial dysfunction, but its pathophysiological basis is still debated.

Methods

Twenty-six consecutive, drug-na?ve, de novo PD patients underwent an extended neuropsychological battery, dopamine transporter (DAT) and brain perfusion single photon emission computed tomography (SPECT). We previously reported that nigrocaudate impairment correlates with executive functions, and nigroputaminal impairment with visuospatial abilities. Here perfusion SPECT was first compared between the PD group and age-matched controls (CTR). Then, perfusion SPECT was correlated with both DAT SPECT and four neuropsychological factors by means of voxel-based analysis (SPM8) with a height threshold of p?p?Results Significant hypoperfusion was found in an occipital area of the MAH in PD patients as compared to CTR. Executive functions directly correlated with brain perfusion in bilateral posterior cingulate cortex and precuneus in the less affected hemisphere (LAH), while verbal memory directly correlated with perfusion in the precuneus, inferior parietal lobule and superior temporal gyrus in the LAH. Furthermore, positive correlation was highlighted between nigrocaudate and nigroputaminal impairment and brain perfusion in the precuneus, posterior cingulate and parahippocampal gyri of the LAH.

Conclusion

These data support the evidence showing an early involvement of the cholinergic system in the early cognitive dysfunction and point to a more relevant role of parietal lobes and posterior cingulate in executive functions in PD.     

Initial experience of carotid artery stenting using the Carotid WALLSTENT and FilterWire EZ in Japan

Purpose

The Carotid WALLSTENT (CWS) and Filter-Wire EZ (FWEZ) embolic protection devices for use in carotid arterial stenting (CAS) were newly approved for national health insurance coverage in Japan in April 2010. This article describes our initial experience of CAS using the CWS and FWEZ.

Material and methods

A group of 14 patients (12 men, 2 women; mean age 70.1 years, range 59?C83 years) with 15 carotid artery stenoses at high risk for carotid endarterectomy were treated by CAS using the CWS and FWEZ. Of these stenoses, 5 were symptomatic with ??50% stenosis of the common or internal carotid artery (ICA), and 10 were asymptomatic with ??80% stenosis. The rates of technical success, ICA flow impairment during filter protection, periprocedural ischemic stroke, 30-day major adverse events (MAEs) (stroke, death, myocardial infarction), and development of new ischemic lesions on diffusion-weighted imaging (DWI) were assessed.

Results

CAS was successful in all cases. There was no ICA flow impairment, periprocedural ischemic stroke, or MAEs. DWI showed new ipsilateral ischemic lesions in only one patient (6.7%).

Conclusion

Our initial clinical experience using the CWS and FEWZ for CAS was generally excellent, and the incidence of postprocedural ischemic lesions was low.     

CT measurements prior to computer-assisted total knee arthroplasty do not improve rotational placement of the femoral component

Purpose

The aim of this study is to determine whether computer-assisted surgery (CAS) can gain more precision by utilizing information from pre-operative computed tomography (CT).

Methods

Sixty-five patients undergoing total knee arthroplasty in 2008 were included. On pre- and post-operative CT, epicondylar and posterior condylar lines were drawn and the posterior condylar angle between these two lines measured. During the surgery, epicondylar and posterior condylar lines were also registered before and after CAS-guided cuts were made. CAS was used to fix the orientation of the cutting guide on the distal femur at 3° of external rotation from the posterior condylar line.

Results

There was no correlation between CT measurements and CAS measurements. All orientations of the lines (relative to the horizontal) and angles measured using CT were significantly different (p?<?0.05).

Conclusion

No relationship was found between pre-operative CT measurements and peri-operative CAS measurements used to orient the femoral component. Data obtained from CT cannot be used peri-operatively with CAS to improve rotational setting of the femoral component.

Level of evidence

Therapeutic study, Level II.     

Factors affecting long-term restenosis after carotid stenting for carotid atherosclerotic disease

Introduction

The most significant factors leading to restenosis are yet to be described in the literature. The purpose of our study was to identify the incidence of restenosis in our patients with carotid artery stenting (CAS) for carotid atherosclerotic disease and to identify risk factors that are significantly responsible or related to the restenosis.

Methods

In this retrospective analysis of patients who underwent CAS for atherosclerotic disease between years 2002 and 2006, we studied various demographic, clinical, and medical factors, plaque characteristics, and technical aspects of CAS. All patients were followed up with carotid Doppler ultrasound at baseline (after 2 to 4?weeks of CAS) and then with Doppler ultrasound and clinically for various intervals of time. The restenosis was classified based on carotid Doppler ultrasound results. Clinically, restenosis was classified as symptomatic or asymptomatic. Pearson correlation coefficient was used to assess the statistical correlation of the different factors with the incidence of restenosis.

Results

We had a total of 105 patients, with a total of 204.6 patient-year follow-up (mean, 1.95?years; range, 0?C7.3?years). The overall incidence of restenosis was 26.7?% (n?=?28): mild, 7.6?% (n?=?8); moderate, 10.5?% (asymptomatic, 11; symptomatic, 0); and severe, 8.6?% (asymptomatic, 5; symptomatic, 4). Overall, 14.3?% (n?=?4) patients with restenosis were symptomatic and 7.1?% (n?=?2) underwent retreatment. Post-stenting residual stenosis greater than either 30?% (p?=?0.016) or 50?% (p?=?0.05) were significant for long-term restenosis. Plaques longer than 20?mm were significantly related to restenosis (p?<?0.001).

Conclusion

The most important factor to explain restenosis was the immediate post-CAS residual stenosis and length of the plaque.     

Acute neurocognitive impairment during cranial radiation therapy in patients with intracranial tumors

Background and Purpose

The objective of the current study was to evaluate the acute effects of cranial radiation therapy (CNS-RT) using different radiation doses (0, 1.8, 2, 3, ≥ 20 Gy) on cognitive function with special emphasis on memory. We assessed patients with and without intracranial tumors to distinguish between direct and indirect radiation effects on brain tissue.

Materials and Methods

Eighty-two patients were evaluated with neuropsychological testing before and acutely after radiotherapy (RT). Sixty-four patients received RT to the brain (55 with, 9 without intracranial tumor). Eighteen patients treated with RT to the breast served as controls.

Results

Patients with intracranial tumor demonstrated attention (19–38th percentile) and verbal memory scores (34–46th percentile) below the population average at baseline. The average Verbal Memory score was significantly different between patients with intracranial tumor and controls both at baseline (38th vs. 58th percentile) and after irradiation (27th vs. 52th percentile). Patients with preexisting peritumoral edema performed worse than patients without edema and controls. Radiation dose-related deficits were seen for working memory performance in patients with intracranial tumor.

Conclusion

Our data indicate no measurable impairment of cognitive functioning acutely after prophylactic cranial irradiation. Patients with intracranial tumor show a deterioration of almost all memory functions with a dose-dependent impairment in working memory. Patients with preexisting peritumoral brain edema show the strongest deterioration.     

Diffusion tensor tractography-based analysis of the cingulum: clinical utility and findings in traumatic brain injury with chronic sequels

Introduction

To evaluate the clinical utility of quantitative diffusion tensor tractography (DTT) and tractography-based core analysis (TBCA) of the cingulum by defining the reproducibility, normal values, and findings in traumatic brain injury (TBI).

Methods

Eighty patients with TBI and normal routine MRI and 78 controls underwent MRI at 3T. To determine reproducibility, 12 subjects were scanned twice. Superior (SC) and inferior (IC) cingulum were analyzed separately by DTT (fractional anisotropy (FA) thresholds 0.15 and 0.30). TBCA was performed from volumes defined by tractography with gradually changed FA thresholds. FA values were correlated with clinical and neuropsychological data.

Results

The lowest coefficient of variation was obtained at DTT threshold 0.30 (2.0 and 2.4 % for SC and IC, respectively), but in proportion to standard deviations of normal controls, the reproducibility of TBCA was better in SC and similar to that of DTT in IC. In patients with TBI, volume reduction with loss of peripheral fibers was relatively common; mean FA was mostly normal in these tractograms. The frequency of FA reductions (>2 SD) was in DTT smaller than in TBCA, in which FA decrease was present in 42 (13.1 %) of the 320 measurements. Central FA values in SC predicted visuoperceptual ability, and those in left IC predicted cognitive speed, language, and communication ability (p?Conclusion Tractography-based measurements have sufficient reproducibility for demonstration of severe abnormalities of the cingulum. TBCA is preferential for clinical FA analysis, because it measures corresponding areas in patients and controls without inaccuracies due to trauma-induced structural changes.     

Altered intrinsic brain activity after chemotherapy in patients with gastric cancer: A preliminary study

Objectives

To characterize the pattern of altered intrinsic brain activity in gastric cancer patients after chemotherapy (CTx).

Methods

Patients before and after CTx (n?=?14) and control subjects (n?=?11) underwent resting-state functional MRI (rsfMRI) at baseline and 3 months after CTx. Regional homogeneity (ReHo), amplitude of low-frequency fluctuation (ALFF), and fractional ALFF (fALFF) were calculated and compared between the groups using the two-sample t test. Correlation analysis was also performed between rsfMRI values (i.e., ReHo, ALFF, and fALFF) and neuropsychological test results.

Results

Patients showed poor performance in verbal memory and executive function and decreased rsfMRI values in the frontal areas even before CTx and showed decreased attention/working memory and executive function after CTx compared to the control subjects. In direct comparison of values before and after CTx, there were no significant differences in neuropsychological test scores, but decreased rsfMRI values were observed at the frontal lobes and right cerebellar region. Among rsfMRI values, lower ALFF in the left inferior frontal gyrus was significantly associated with poor performance of the executive function test.

Conclusions

We observed decreased attention/working memory and executive function that corresponded to the decline of frontal region activation in gastric cancer patients who underwent CTx.

Key Points

? Intrinsic brain activity of gastric cancer patients after chemotherapy was described. ? Brain activity and neuropsychological test results were correlated. ? Working memory and executive function decreased after chemotherapy. ? Decreased cognitive function corresponded to decreased activation of the frontal region.

     

Characterisation of carotid plaques with ultrasound elastography: feasibility and correlation with high-resolution magnetic resonance imaging

Objectives

To evaluate the ability of ultrasound non-invasive vascular elastography (NIVE) strain analysis to characterise carotid plaque composition and vulnerability as determined by high-resolution magnetic resonance imaging (MRI).

Methods

Thirty-one subjects with 50 % or greater carotid stenosis underwent NIVE and high-resolution MRI of internal carotid arteries. Time-varying strain images (elastograms) of segmented plaques were generated from ultrasonic raw radiofrequency sequences. On MRI, corresponding plaques and components were segmented and quantified. Associations between strain parameters, plaque composition and symptomatology were estimated with curve-fitting regressions and Mann–Whitney tests.

Results

Mean stenosis and age were 72.7 % and 69.3 years, respectively. Of 31 plaques, 9 were symptomatic, 17 contained lipid and 7 were vulnerable on MRI. Strains were significantly lower in plaques containing a lipid core compared with those without lipid, with 77–100 % sensitivity and 57–79 % specificity (P?<?0.032). A statistically significant quadratic fit was found between strain and lipid content (P?<?0.03). Strains did not discriminate symptomatic patients or vulnerable plaques.

Conclusions

Ultrasound NIVE is feasible in patients with significant carotid stenosis and can detect the presence of a lipid core with high sensitivity and moderate specificity. Studies of plaque progression with NIVE are required to identify vulnerable plaques.

Key points

? Non-invasive vascular elastography (NIVE) provides additional information in vascular ultrasound ? Ultrasound NIVE is feasible in patients with significant carotid stenosis ? Ultrasound NIVE detects a lipid core with high sensitivity and moderate specificity ? Studies on plaque progression with NIVE are required to identify vulnerable plaques     

Intervention versus Aggressive Medical Therapy for Cognition in Severe Asymptomatic Carotid Stenosis

BACKGROUND AND PURPOSE:Asymptomatic carotid stenosis of ≥70% increases the incidence of microembolism and/or chronic hypoperfusion, which may consequently impair neurocognition and brain connections. We sought controlled evidence for any cognitive benefit of aggressive medical therapy and combined carotid revascularization.MATERIALS AND METHODS:Patients with asymptomatic, unilateral, ≧70% stenosis of the extracranial ICA chose either aggressive medical therapy alone or in combination with carotid artery stent placement in this nonrandomized controlled study. They were examined with a battery of neuropsychological tests, structural MR imaging, DTI, and resting-state fMRI before and 3 months after treatment.RESULTS:Forty patients were included with 15 in the medical group and 25 in the stent-placement group. Among them, 13 and 21 in the respective groups completed neuroimaging follow-up. The baseline characteristics and the changes in cognitive performance during 3 months showed no differences between treatment groups. Nevertheless, compared with the medical group, the stent-placement group showed subjective dizziness alleviation (P = .045) and a small increase in fractional anisotropy at the splenium of the corpus callosum and the posterior periventricular white matter ipsilateral to carotid artery stent placement. Moreover, only the stent-placement group showed interval improvement in immediate memory and visuospatial performance, which was accompanied by an increase of functional connectivity at the insular cortex of the dorsal attention network and the medial prefrontal cortex of the default mode network.CONCLUSIONS:Both aggressive medical therapy alone and combined carotid revascularization in ≧70% asymptomatic carotid stenosis similarly preserved cognition during 3-month follow-up, though the latter had the potential for dizziness alleviation and cognitive and connectivity enhancement.

Interventional revascularization for ≥60% asymptomatic ICA stenosis has long been debated, given the decreasing annual risk of ipsilateral ischemic stroke in these patients from 2.3% to 0.5% with the development of contemporary optimal medical treatment.^1–4 However, some of these patients carry a higher risk of stroke than others despite optimal medical treatment. Patients with detectable embolic signals by transcranial Doppler have a high annual risk (7%) of stroke.⁵ Stenotic degree of ≥90%, poor collaterals, and echolucent plaque texture could also stratify patients into groups with varying high stroke risk to >4% annually.^6,7 Thus, interventional revascularization should be considered in such patients. Recently, long-term randomized trials, the Asymptomatic Carotid Trial⁸ and the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST)⁹ demonstrated that there was no difference in the rate of late ipsilateral stroke after carotid endarterectomy or carotid artery stent placement (CAS) in asymptomatic and symptomatic patients. Of asymptomatic patients, the 5-year cumulative rate of stroke-free survival was 93.1% in the CAS group and 94.7% in the carotid endarterectomy group.⁸Hence, asymptomatic carotid stenosis has been viewed from a changing perspective from stroke risk to cognitive susceptibility.^10,11 We previously demonstrated that patients with unilateral asymptomatic carotid stenosis of ≥70% had more dizziness/unsteadiness and poorer verbal memory, executive function, and visuospatial perception than the healthy controls, accompanied by extensive widespread disruption of long-range structural and functional connectivity.^12,13 The mechanisms are likely attributed to microemboli from unstable carotid plaques⁵ and/or chronic hypoperfusion.^14,15 Single-arm studies of carotid revascularization accomplished by either carotid endarterectomy or CAS reported the controversial results of cognitive enhancement in patients with asymptomatic carotid stenosis.^15–20 However, there is a lack of medical-controlled evidence reflecting contemporary medical improvement and risk-benefit balance of interventions for cognitive preservation. Here, we investigate the impact of aggressive medical treatment with or without combined carotid revascularization on neurocognitive and connectivity outcomes at 3 months after treatment in patients with ≧70% asymptomatic carotid stenosis.