Lesion Overlap Research Articles

Lesion mapping of stroke-related erectile dysfunction.

Acute ischaemic stroke in brain areas contributing to male sexual function may impair erectile function depending on the lesion site. This study intended to determine associations between stroke-related erectile dysfunction and cerebral ischaemic lesion sites using voxel-based lesion mapping. In 52 males (mean age 60.5 ± 10.5 years) with first-ever ischaemic strokes, we assessed erectile function after and retrospectively 3 months prior to the stroke using scores of the 5-item International Index of Erectile Function-5 questionnaire. We assessed cardiovascular risk factors and determined clinical stroke severity and infarct volumes as well as total brain volume by neuroimaging. We calculated correlations between patient age, clinical stroke severity, infarct volumes as well as brain volumes and the difference between erectile dysfunction scores before and after stroke. Moreover, we compared patient age, prevalence of cardiovascular risk factors, clinical stroke severity, infarct volumes and brain volumes of patients with unchanged and deteriorated erectile function after stroke. The infarcts were manually outlined and transformed into stereotaxic space. We determined the lesion overlap and performed subtraction analyses of lesions. In a voxel-based lesion analysis, the difference between erectile dysfunction scores before and after stroke was correlated with the lesion site using t-test statistics. Finally, we conducted a region of interest-based multivariate linear regression analysis that was adjusted for potential confounding factors including patient age, clinical stroke severity, imaging modality, lesion size and brain volume. In 32 patients (61.5%) erectile dysfunction scores declined after the stroke and therefore had stroke-related erectile dysfunction. Deterioration of erectile dysfunction scores was not associated with patient age, clinical stroke severity, infarct volume, brain volume, and cardiovascular risk factors. The voxel-wise subtraction analysis showed associations between stroke-related erectile dysfunction and lesion sites in the right occipito-parietal cortex and thalamus, as well as in the left insula and adjacent temporo-parietal areas. Using voxel-wise t-test statistics, we showed associations between deterioration of erectile function and lesion sites in the right occipital and thalamic region, and the left parietal association area. The linear regression analysis showed that stroke-related erectile dysfunction remained associated with lesions of the right occipital and left parietal association areas after adjusting for confounding factors. In conclusion, our voxel-wise analysis indicates that deteriorating erectile function after stroke is associated with lesions in the right occipito-parietal and thalamic areas integrating visual and somatosensory information, as well as lesions in the left insular and adjacent parieto-temporal areas contributing to generating and mapping visceral arousal states.

White Matter Correlates of Auditory Comprehension Outcomes in Chronic Post-Stroke Aphasia

Neuroimaging studies have shown that speech comprehension involves a number of widely distributed regions within the frontal and temporal lobes. We aimed to examine the differential contributions of white matter connectivity to auditory word and sentence comprehension in chronic post-stroke aphasia. Structural and diffusion MRI data were acquired on 40 patients with chronic post-stroke aphasia. A battery of auditory word and sentence comprehension tests were administered to all the patients. Tract-based spatial statistics were used to identify areas in which white matter integrity related to specific comprehension deficits. Relevant tracts were reconstructed using probabilistic tractography in healthy older participants, and the mean values of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) of the entire tracts were examined in relation to comprehension scores. Anterior temporal white matter integrity loss and involvement of the uncinate fasciculus related to word-level comprehension deficits (RFA = 0.408, P = 0.012; RMD = −0.429, P = 0.008; RAD = −0.424, P = 0.009; RRD = −0.439, P = 0.007). Posterior temporal white matter integrity loss and involvement of the inferior longitudinal fasciculus related to sentence-level comprehension deficits (RFA = 0.382, P = 0.02; RMD = −0.461, P = 0.004; RAD = −0.457, P = 0.004; RRD = −0.453, P = 0.005). Loss of white matter integrity in the inferior fronto-occipital fasciculus related to both word- and sentence-level comprehension (word-level scores: RFA = 0.41, P = 0.012; RMD = −0.447, P = 0.006; RAD = −0.489, P = 0.002; RRD = −0.432, P = 0.008; sentence-level scores: RFA = 0.409, P = 0.012; RMD = −0.413, P = 0.011; RAD = −0.408, P = 0.012; RRD = −0.413, P = 0.011). Lesion overlap, but not white matter integrity, in the arcuate fasciculus related to sentence-level comprehension deficits. These findings suggest that word-level comprehension outcomes in chronic post-stroke aphasia rely primarily on anterior temporal lobe pathways, whereas sentence-level comprehension relies on more widespread pathways including the posterior temporal lobe.

Automated Ischemic Lesion Segmentation in MRI Mouse Brain Data after Transient Middle Cerebral Artery Occlusion.

Magnetic resonance imaging (MRI) has become increasingly important in ischemic stroke experiments in mice, especially because it enables longitudinal studies. Still, quantitative analysis of MRI data remains challenging mainly because segmentation of mouse brain lesions in MRI data heavily relies on time-consuming manual tracing and thresholding techniques. Therefore, in the present study, a fully automated approach was developed to analyze longitudinal MRI data for quantification of ischemic lesion volume progression in the mouse brain. We present a level-set-based lesion segmentation algorithm that is built using a minimal set of assumptions and requires only one MRI sequence (T2) as input. To validate our algorithm we used a heterogeneous data set consisting of 121 mouse brain scans of various age groups and time points after infarct induction and obtained using different MRI hardware and acquisition parameters. We evaluated the volumetric accuracy and regional overlap of ischemic lesions segmented by our automated method against the ground truth obtained in a semi-automated fashion that includes a highly time-consuming manual correction step. Our method shows good agreement with human observations and is accurate on heterogeneous data, whilst requiring much shorter average execution time. The algorithm developed here was compiled into a toolbox and made publically available, as well as all the data sets.

The Calculation of Language Lateralization Indices in Post-stroke Aphasia: A Comparison of a Standard and a Lesion-Adjusted Formula

Background: The language lateralization index (LI) is a valuable tool in functional magnetic resonance imaging (fMRI) research, especially in people with post-stroke aphasia. However, there is inconsistent consideration for the overlap of lesions with regions of interest (ROIs). The purpose of this study was to determine whether standard LI (SLI) and lesion-adjusted LI (LALI) formulae generate different LI values and language lateralization classification for people with post-stroke chronic aphasia.Methods: SLI and LALI were calculated for an event-related (overt) verb generation task in an anterior and a posterior language ROI. Twelve people with aphasia due to a single left-hemispheric infarct (11 right-handed; 1 left-handed; 77.2 ± 41.7 months post-stroke) were included (eight females; 57 ± 8.88 years). Spearman correlation coefficients and intraclass correlation coefficients were calculated to determine the relationship of the LI values generated by the SLI and the LALI formulas. Fischer’s exact test and a weighted Cohen’s Kappa determined the difference in language lateralization classification and agreement in the classification. Spearman correlation was used to examine the relationship between the difference in lateralization values produced by the LALI and SLI calculations with (1) lesion size, (2) the percentage of lesion overlap in each ROI, and (3) aphasia severity.Results: The two calculation methods were highly correlated and produced similar LI Values, yet yielded significantly different classification for language lateralization. Further, a more leftward LI resulted from application of the LALI formula in 10 participants, in either the anterior ROI (n = 3) or the posterior ROI (n = 7). Finally, for the posterior ROI only, significant correlations were revealed between the two calculation methods and the (1) lesion size and (2) percent of overlap with the ROI.Discussion: While both approaches produce highly correlated LI values, differences in activation lateralization between formulas were observed, including changes in lateralization classification. Examination of the issues raised in the current investigation need to be replicated with a larger sample to determine the utility of a LALI formula in predicting behavioral performance; the findings may have implications for understanding and interpreting fMRI data of people with post-stroke aphasia.

Cytologic and Immunohistochemical Evaluation of Low-Grade Spindle Cell Lesions of the Gastrointestinal Tract.

Spindle cell lesions of the gastrointestinal tract are relatively uncommon compared with the frequency of their epithelial counterparts. Although gastrointestinal stromal tumors and leiomyomas are the most commonly encountered spindle cell lesions in the stomach and esophagus, respectively, there are other less common diagnostic entities that should be considered for accurate diagnoses as well as appropriate patient treatment and clinical follow-up. Given the morphologic overlap of low-grade spindle cell lesions on cytologic preparations, ancillary studies play a key role in differentiating these lesions from one another.

Histopathological spectrum of Psoriasiform dermatitis

Background: Psoriasiform dermatitis is a frequently encountered terminology in a wide variety of inflammatory dermatoses. It often poses challenges to both dermatologists and pathologists alike. Clinical features when considered alone may not be reliable, as they vary with both disease duration and treatment. On the contrary, histopathological material constitutes definite hard evidence, which can be preserved and will continue to be available for future review. The objective of the study is to study the histopathological findings in Psoriasiform dermatitis.Materials and Methods: This is a retrospective study in a tertiary care centre in Kerala, South India. All cases diagnosed as Psoriasis or mentioned as one of the differential diagnosis were included. The material included 66 skin biopsies. Patients with a previous diagnosis of the same were excluded from the study.Results: The lesions comprised 9% of the total number of skin biopsies. The age distribution pattern revealed that the highest percentage was in the 41-60 year age group (50%) with a male preponderance of 65%. Psoriasis was the most common lesion (60.60%) and Lichen simplex chronicus was the second most common lesion (10.60 %), encountered in the study.Conclusion: Some of the histopathological features are specific and characteristic for each entity like Psoriasis, Pityriasis rubra pilaris, Pityriasis rosea and Inflammatory linear verrucous epidermal nevus whereas some overlap in lesions like Prurigo nodularis, Lichen simplex chronicus and Allergic contact dermatitis. Hence, combination of proper clinical observation and histopathological study will give a conclusive diagnosis.

Neural Basis of Acquired Amusia and Its Recovery after Stroke.

Although acquired amusia is a relatively common disorder after stroke, its precise neuroanatomical basis is still unknown. To evaluate which brain regions form the neural substrate for acquired amusia and its recovery, we performed a voxel-based lesion-symptom mapping (VLSM) and morphometry (VBM) study with 77 human stroke subjects. Structural MRIs were acquired at acute and 6 month poststroke stages. Amusia and aphasia were behaviorally assessed at acute and 3 month poststroke stages using the Scale and Rhythm subtests of the Montreal Battery of Evaluation of Amusia (MBEA) and language tests. VLSM analyses indicated that amusia was associated with a lesion area comprising the superior temporal gyrus, Heschl's gyrus, insula, and striatum in the right hemisphere, clearly different from the lesion pattern associated with aphasia. Parametric analyses of MBEA Pitch and Rhythm scores showed extensive lesion overlap in the right striatum, as well as in the right Heschl's gyrus and superior temporal gyrus. Lesions associated with Rhythm scores extended more superiorly and posterolaterally. VBM analysis of volume changes from the acute to the 6 month stage showed a clear decrease in gray matter volume in the right superior and middle temporal gyri in nonrecovered amusic patients compared with nonamusic patients. This increased atrophy was more evident in anterior temporal areas in rhythm amusia and in posterior temporal and temporoparietal areas in pitch amusia. Overall, the results implicate right temporal and subcortical regions as the crucial neural substrate for acquired amusia and highlight the importance of different temporal lobe regions for the recovery of amusia after stroke. Lesion studies are essential in uncovering the brain regions causally linked to a given behavior or skill. For music perception ability, previous lesion studies of amusia have been methodologically limited in both spatial accuracy and time domain as well as by small sample sizes, providing coarse and equivocal information about which brain areas underlie amusia. By using longitudinal MRI and behavioral data from a large sample of stroke patients coupled with modern voxel-based analyses methods, we were able provide the first systematic evidence for the causal role of right temporal and striatal areas in music perception. Clinically, these results have important implications for the diagnosis and prognosis of amusia after stroke and for rehabilitation planning.

Localization and patterns of Cerebral dyschromatopsia: A study of subjects with prospagnosia

ObjectiveCerebral dyschromatopsia is sometimes associated with acquired prosopagnosia. Given the variability in structural lesions that cause acquired prosopagnosia, this study aimed to investigate the structural correlates of prosopagnosia-associated dyschromatopsia, and to determine if such colour processing deficits could also accompany developmental prosopagnosia. In addition, we studied whether cerebral dyschromatopsia is typified by a consistent pattern of hue impairments. MethodsWe investigated hue discrimination in a cohort of 12 subjects with acquired prosopagnosia and 9 with developmental prosopagnosia, along with 42 matched controls, using the Farnsworth-Munsell 100-hue test. ResultsWe found impaired hue discrimination in six subjects with acquired prosopagnosia, five with bilateral and one with a unilateral occipitotemporal lesion. Structural MRI analysis showed maximum overlap of lesions in the right and left lingual and fusiform gyri. Fourier analysis of their error scores showed tritanopic-like deficits and blue-green impairments, similar to tendencies displayed by the healthy controls. Three subjects also showed a novel fourth Fourier component, indicating additional peak deficits in purple and green-yellow regions. No subject with developmental prosopagnosia had impaired hue discrimination. ConclusionsIn our subjects with prosopagnosia, dyschromatopsia occurred in those with acquired lesions of the fusiform gyri, usually bilateral but sometimes unilateral. The dyschromatopsic deficit shows mainly an accentuation of normal tritatanopic-like tendencies. These are sometimes accompanied by additional deficits, although these could represent artifacts of the testing procedure.

Spatial agreement between Goldmann visual field defects and fundus autofluorescence in patients with birdshot chorioretinopathy.

BackgroundThe purpose of this paper is to study the spatial agreement between visual field defects and ultra-wide field (UWF) fundus autofluorescence (FAF) in patients with birdshot chorioretinopathy (BSCR). The study is a retrospective, cross-sectional analysis of a university uveitis practice. Eight (8) eyes of five (5) patients with BSCR were included. Inclusion criteria were ability to fixate reliably. Goldmann visual fields (GVF) and UWF FAF were obtained, digitalized, and standardized. Analysis was performed by measuring areas of overlap of hypo-autofluorescent FAF lesions and GVF scotomas within the central 60°. Overlap was calculated as a percentage of the total area of FAF and GVF, respectively. Average areas were also calculated.ResultsThe mean age of the subjects was 51 ± 12.28 years (range 38–69 years). 14 ± 23 % of the total lesion area identified as hypo-autofluorescent on FAF overlapped with scotoma. 28 ± 41 % of the GVF scotomas overlapped with hypo-autofluorescent FAF lesions. Average area of FAF hypo-autofluorescence was much larger (15.19 disc areas) than GVF (3.45 disc areas).ConclusionsThere appear to be larger total areas of hypo-autofluorescence on FAF than scotoma evidenced by GVF and only a small amount of overlap. The finding suggests that GVF is relatively insensitive to anatomic loss, which can be detected using FAF. Further studies are required to assess whether this finding holds true for automated white-on-white perimetry. In addition, more selective psychophysical stimuli may have higher sensitivity in detecting early functional loss that accompanies anatomic damage.

Stillbirth, hypertensive disorders of pregnancy, and placental pathology

IntroductionStillbirth, preeclampsia, and gestational hypertension (PE/GH) have similar clinical risk factors and redundant placental pathology. We aim to discern if stillbirth with PE/GH has a particular phenotype by comparing stillbirths with and without PE/GH. MethodsSecondary analysis of the Stillbirth Collaborative Research Network, a population-based cohort study of all stillbirths and a sample of live births from 2006 to 2008 in five catchment areas. We compared placental pathology between stillbirths and with and without PE/GH, stratified by term or preterm. We also compared placental pathology between stillbirths and live births with PE/GH. Results79/518 stillbirths and 140/1200 live births had PE/GH. Amongst preterm stillbirths, there was higher feto-placental ratio in PE/GH pregnancies (OR 1.24 [1.11, 1.37] per unit increase), and there were more parenchymal infarctions (OR 5.77 [3.18, 10.47]). Among PE/GH pregnancies, stillbirths had increased maternal and fetal vascular lesions, including retroplacental hematoma, parenchymal infarction, fibrin deposition, fetal vascular thrombi, and avascular villi. DiscussionStillbirth pregnancies are overwhelmingly associated with placental lesions. Parenchymal infarctions are more common in PE/GH preterm stillbirths, but there is significant overlap in lesions found in stillbirths and PE/GH.

Abstract TP57: Assessing Acute Infarct Growth and Evolution Using Apparent Diffusion Coefficient and Quantitative R2 Imaging

Introduction: Ischemic stroke is caused by cellular injury to the neurovascular unit. During the early stages of stroke onset, MR diffusion-weighted Imaging (DWI) provides sensitive detection of cytotoxic injury. However, measurement of free-water with quantitative R2 (qR2) relaxometry is generally ignored. Hypothesis: Inclusion of qR2 with DWI will better characterize the heterogeneity of acute ischemia and infarct growth. Methods: 36 ischemic stroke patients (age; 72 ± 17) were imaged acutely (baseline) and at 24h on a 3 T MR scanner. Apparent diffusion coefficient (ADC) and qR2 maps were calculated from DWI and multi-echo T2 data sets using ANTONIA software. Volumetric segmentation of qR2 lesions were performed using a threshold -12.5% of the mean contra lateral side value. ADC lesions were segmented using a threshold of 630x10^-6mm^2/s. Lesion overlap of qR2 and ADC segmented volumes was also calculated using DICE coefficient. Results: Time from stroke onset to MRI was 4:5 ± 0.16h, and recanalization was confirmed (10 ± 1.3h) in the acute period. Treatment was provided with tPA in 27/36 (75%) or endovascular therapy in 15/36 (41.7%) or both in 9/36 (25%). Ischemic lesions were identified in 31/36 (86%) patients based on ADC. ADC lesions were identified in 23/31 (74%) at baseline and 27/31 (87%) at 24h, QR2 lesions were observed in 14/27 (52 %) at baseline and 15/27 (56%) at 24h. The Figure shows ADC and qR2 volume changes over time. QR2 and ADC volume overlap was 10.7% at baseline and 19.9% at 24h. The percentage change in qR2 lesion was 189.2%, compared to ADC lesion growth of 90.50%. Lesion growth was more frequently demonstrated by qR2 than ADC (Fishers exact p<0.05). Conclusion: Acute ischemic lesion growth size was more frequently demonstrated by qR2 than by ADC. Acquisition of ADC alone underestimates severity of acute ischemia and infarct growth. Combining quantitative MRI using ADC and qR2 provide improved characterization of acute infarct evolution.

Bioresorbable Scaffold vs. Second Generation Drug Eluting Stent in Long Coronary Lesions requiring Overlap: A Propensity-Matched Comparison (the UNDERDOGS study)

BackgroundRandomized clinical trials on bioresorbable scaffolds (BRS) enrolled patients with simple coronary lesions. The present study was sought to give preliminary findings about safety of BRS implantation in overlap in long coronary lesions. MethodsFrom June 2012 to January 2015, we prospectively collected data from 162 consecutive patients receiving overlapping BRS implantation in the 16 participating institutions. We applied a propensity-score to match BRS-treated patients with 162 patients receiving second generation drug eluting stents (DES) in overlap. The primary endpoint was a device-oriented endpoint (DOCE), including cardiac death, target vessel myocardial infarction, and target lesion revascularization. ResultsDOCE rate did not significantly differ between the two groups (5.6% in BRS group vs. 7.4% in DES group, HR 0.79, 95%CI 0.37–3.55, p=0.6). Also stent/scaffold thrombosis did not differ between groups (1.2% in BRS group vs. 1.9% in DES group, p=0.6). Occurrence of procedural-related myocardial injury was significantly higher in the BRS group (25% vs. 12%, p=0.001), although it was not related to DOCE (HR 1.1, 95%CI 0.97–1.2, p=0.2). Imaging techniques and enhanced stent visualization systems were significantly more employed in the BRS group (p=0.0001 for both). Procedure length, fluoroscopy time and contrast dye amount were significantly higher in the BRS group (p=0.001, p=0.001 and p=0.01, respectively). ConclusionsOverlapping BRS utilization in long coronary lesions showed a comparable DOCE rate at 1year if compared to second generation DES. Further and larger studies are on demand to confirm our findings.

The Prognosis and Recovery of Aphasia Related to Stroke Lesion.

ObjectiveTo investigate the effects of specific brain lesions on prognosis and recovery of post-stroke aphasia, and to assess the characteristic pattern of recovery.MethodsTotal of 15 subjects with first-ever, left hemisphere stroke, who were right handed, and who completed language assessment using the Korean version of the Western Aphasia Battery (K-WAB) at least twice during the subacute and chronic stages of stroke, were included. The brain lesions of the participants were evaluated using MRI-cron, SPM8, and Talairach Daemon software.ResultsSubtraction of the lesion overlap map of the participants who showed more than 30% improvement in the aphasia quotient (AQ) by the time of their chronic stage (n=9) from the lesion overlap map of those who did not show more than 30% improvement in the AQ (n=6) revealed a strong relationship with Broca's area, inferior prefrontal gyrus, premotor cortex, and a less strong relationship with Wernicke's area and superior and middle temporal gyri. The culprit lesion related to poor prognosis, after grouping the subjects according to their AQ score in the chronic stage (a cut score of 50), revealed a strong relationship with Broca's area, superior temporal gyrus, and a less strong relationship with Wernicke's area, prefrontal cortex, and inferior frontal gyrus.ConclusionBrain lesions in the Broca's area, inferior prefrontal gyrus, and premotor cortex may be related to slow recovery of aphasia in patients with left hemisphere stroke. Furthermore, involvement of Broca's area and superior temporal gyrus may be associated with poor prognosis of post-stroke aphasia.

Headache in acute ischaemic stroke: a lesion mapping study.

Headache is a common symptom in acute ischaemic stroke, but the underlying mechanisms are incompletely understood. The aim of this lesion mapping study was to identify brain regions, which are related to the development of headache in acute ischaemic stroke. Patients with acute ischaemic stroke (n = 100) were assessed by brain MRI at 3 T including diffusion weighted imaging. We included 50 patients with stroke and headache as well as 50 patients with stroke but no headache symptoms. Infarcts were manually outlined and images were transformed into standard stereotaxic space using non-linear warping. Voxel-wise overlap and subtraction analyses of lesions as well as non-parametric statistics were conducted. The same analyses were carried out by flipping of left-sided lesions, so that all strokes were transformed to the same hemisphere. Between the headache group as well as the non-headache there was no difference in infarct volumes, in the distribution of affected vascular beds or in the clinical severity of strokes. The headache phenotype was tension-type like in most cases. Subtraction analysis revealed that in headache sufferers infarctions were more often distributed in two well-known areas of the central pain matrix: the insula and the somatosensory cortex. This result was confirmed in the flipped analysis and by non-parametric statistical testing (whole brain corrected P-value < 0.01). To the best of our knowledge, this is the first lesion mapping study investigating potential lesional patterns associated with headache in acute ischaemic stroke. Insular strokes turned out to be strongly associated with headache. As the insular cortex is a well-established region in pain processing, our results suggest that, at least in a subgroup of patients, acute stroke-related headache might be centrally driven.

Improving the Spatial Alignment in PET/CT Using Amplitude-Based Respiration-Gated PET and Respiration-Triggered CT

Respiratory motion during PET can cause inaccuracies in the quantification of radiotracer uptake, which negatively affects PET-guided radiotherapy planning. Quantitative accuracy can be improved by respiratory gating. However, additional miscalculation of standardized uptake value (SUV) in PET images can be caused by inappropriate attenuation correction due to a spatial mismatch between gated PET and CT. In this study, the effect of respiration-triggered CT on the spatial match between CT and amplitude-based respiration-gated PET images is investigated. (18)F-FDG PET/CT was performed in 38 patients. Images were acquired on 2 PET/CT scanners, one without and one with continuous bed motion during PET acquisition. The amplitude limits of the amplitude-based respiration-gated PET were used for the respiration-triggered sequential low-dose CT. Both standard (spiral) and triggered CT scans were used to reconstruct the PET data. Spatial mismatch was quantified using the position difference between the lung-liver boundary in PET and CT images, the distance between PET and CT lung lesions' centroids, and the amount of overlap of lesions indicated by the Jaccard similarity coefficient. Furthermore, the effect of attenuation correction was quantified by measuring SUVs in lung lesions. For triggered CT, the average distance between the lung-liver boundary in PET and CT was significantly reduced (4.5 ± 6.7 mm) when compared with standard CT (9.2 ± 8.1 mm) (P < 0.001). The mean distance between the lesions' centroids in PET and CT images was 6.3 ± 4.0 and 5.6 ± 4.2 mm (P = 0.424), for the standard and triggered CT, respectively. Similarly, the Jaccard similarity coefficient was 0.30 ± 0.21 and 0.32 ± 0.20 (P = 0.609) for standard and triggered CT, respectively. For 6 lesions, there was no overlap of PET and CT when the standard CT was used; compared with the triggered CT, these lesions showed (partial) overlap. The maximum and mean SUV increase of the PET/CT compared with the PET/triggered CT was 5.7% ± 11.2% (P < 0.001) and 6.1% ± 10.2% (P = 0.001), respectively. Amplitude-based respiration-gated PET in combination with respiration-triggered CT resulted in a significantly improved match in the area of the liver dome and a significantly higher SUV for lung lesions. However, lesions in the lungs did not show a consistent improvement in spatial match.

Patients with focal cerebellar lesions show reduced auditory cortex activation during silent reading

Functional neuroimaging studies consistently report language-related cerebellar activations, but evidence from the clinical literature is less conclusive. Here, we attempt to bridge this gap by testing the effect of focal cerebellar lesions on cerebral activations in a reading task previously shown to involve distinct cerebellar regions. Patients (N=10) had lesions primarily affecting medial cerebellum, overlapping cerebellar regions activated during the presentation of random word sequences, but distinct from activations related to semantic prediction generation and prediction error processing. In line with this pattern of activation–lesion overlap, patients did not differ from matched healthy controls (N=10) in predictability-related activations. However, whereas controls showed increased activation in bilateral auditory cortex and parietal operculum when silently reading familiar words relative to viewing letter strings, this effect was absent in the patients. Our results highlight the need for careful lesion mapping and suggest possible roles for the cerebellum in visual-to-auditory mapping and/or inner speech.

Deficits in reflexive covert attention following cerebellar injury.

Traditionally the cerebellum has been known for its important role in coordinating motor output. Over the past 15 years numerous studies have indicated that the cerebellum plays a role in a variety of cognitive functions including working memory, language, perceptual functions, and emotion. In addition, recent work suggests that regions of the cerebellum involved in eye movements also play a role in controlling covert visual attention. Here we investigated whether regions of the cerebellum that are not strictly tied to the control of eye movements might also contribute to covert attention. To address this question we examined the effects of circumscribed cerebellar lesions on reflexive covert attention in a group of patients (n = 11) without any gross motor or oculomotor deficits, and compared their performance to a group of age-matched controls (n = 11). Results indicated that the traditional RT advantage for validly cued targets was significantly smaller at the shortest (50 ms) SOA for cerebellar patients compared to controls. Critically, a lesion overlap analysis indicated that this deficit in the rapid deployment of attention was linked to damage in Crus I and Crus II of the lateral cerebellum. Importantly, both cerebellar regions have connections to non-motor regions of the prefrontal and posterior parietal cortices—regions important for controlling visuospatial attention. Together, these data provide converging evidence that both lateral and midline regions of the cerebellum play an important role in the control of reflexive covert visual attention.

Multiclass Support Vector Machine-Based Lesion Mapping Predicts Functional Outcome in Ischemic Stroke Patients.

PurposeThe aim of this study was to investigate if ischemic stroke final infarction volume and location can be used to predict the associated functional outcome using a multi-class support vector machine (SVM).Material and MethodsSixty-eight follow-up MR FLAIR datasets of ischemic stroke patients with known modified Rankin Scale (mRS) functional outcome after 30 days were used. The infarct regions were segmented and used to calculate the percentage of lesioned voxels in the predefined MNI, Harvard-Oxford cortical and subcortical atlas regions as well as using four problem-specific VOIs, which were identified from the database using voxel-based lesion symptom mapping. An overall of 12 SVM classification models for predicting the corresponding mRS score were generated using the lesion overlap values from the different brain region definitions, stroke laterality information, and the optional parameters infarct volume, admission NIHSS, and patient age.ResultsLeave-one-out cross validations revealed that including information about the stroke location in terms of lesion overlap measurements led to improved mRS prediction results compared to classification models not utilizing the stroke location information. Furthermore, integration of the optional features led to improved mRS prediction results in all cases tested. The problem-specific brain regions and additional integration of the optional features led to the best mRS predictions with a precise multi-value mRS prediction accuracy of 56%, sliding window multi-value mRS prediction accuracy (mRS±1) of 82%, and binary mRS (0-2 vs. 3-5) prediction accuracy of 85%.ConclusionTherefore, a graded SVM-based functional stroke outcome prediction using the problem-specific brain regions for lesion overlap quantification leads to promising results but needs to be further validated using an independent database to rule out a potential methodical bias and overfitting effects. The prediction of the graded mRS functional outcome could be a valuable tool if combined with voxel-wise tissue outcome predictions based on multi-parametric datasets acquired at the acute phase.

Ipsilesional neglect: behavioral and anatomical correlates.

[Correction Notice: An Erratum for this article was reported in Vol 29(2) of Neuropsychology (see record 2014-42242-001). The funding source information was missing from the author note, and A. M. Barrett's institutional affiliation was incorrect. The funding source information and Barrett's correct institutional affiliation are provided in the erratum.] The sparse existing research on ipsilesional neglect supports an association of this disorder with damage to the right frontal and subcortical brain networks. It is believed that dysfunction in these networks may result in primarily "aiming" motor-intentional spatial errors. The purpose of this study was to confirm whether frontal-subcortical circuits are indeed commonly affected in ipsilesional neglect and to determine the relative presence of "aiming" motor-intentional versus "where" perceptual-attentional spatial errors in these individuals. We identified 12 participants with ipsilesional neglect based on a computerized line bisection task and used the line bisection data to quantify participants' perceptual-attentional and motor-intentional errors. We were able to discriminate between these 2 biases using the algebraic solutions for 2 separate equations, one for "aiming" and one for "where" biases. Lesion mapping was conducted for all participants using MRIcron software; lesion checklist and overlap analysis were created from these images. A greater percentage of participants with ipsilesional neglect had frontal/subcortical damage (83%) compared with the expected percentage (27%) observed in published patient samples with contralesional neglect. We observed the greatest area of lesion overlap in frontal lobe white matter pathways. Nevertheless, participants with ipsilesional neglect made primarily "where" rather than "aiming" spatial errors. Our data confirm previous research suggesting that ipsilesional neglect may result from lesions to the right frontal-subcortical networks. Furthermore, in our group, ipsilesional neglect was also strongly associated with primarily "where" perceptual-attentional bias, and less so with "aiming" motor-intentional spatial bias.

Abstract 100: Right Insular Infarction is an Independent Predictor of Mortality in Ischemic Stroke

Introduction: The association between insular infarction and mortality has often been described. However, whether this is simply due to higher lesion volumes is still controversial. Hypothesis: We hypothesized that there is an association between insular infarction and mortality independent of lesion volume. Methods: We included consecutive stroke patients between 01.09.2008 and 11.11.2012 from the 1000Plus data base with an acute ischemic lesion on diffusion-weighted imaging on day one and a completed 90 days follow-up. Insular location of the infarction was determined using the Stroke Lesion Atlas (SLA). The SLA is an in-house developed spatial database for analyses of imaging studies (Figure). In multivariate regression analyses of mortality and insular infarcts we adjusted for age, lesion volume, atrial fibrillation, NIHSS, capsular infarcts, and left hemispheric infarcts. Results: We included 718 patients. Out of 165 patients with insular infarcts 20 patients died; among the 553 patients with lesions outside the Insula 16 patients died (mortality 12% vs. 3%; p&lt;.001). In analyses adjusting for all mentioned confounders insular infarction was not an independent predictor of mortality. After exclusion of NIHSS insular infarcts were independently associated with mortality (OR=3.003, CI 1.41 - 6.38, p=.004). Right insular infarction was an independent mortality predictor adjusted for all confounders including the NIHSS (OR=2.793, CI 1.27 - 6.15, p=.011). Conclusion: Right insular involvement is an independent predictor of mortality in ischemic stroke and may be used to improve identification of patients at risk. Figure. Lesion overlap of patients who survived (A) or died (B). Red indicates voxels involved in at least 15% of patients. Deceased patients show a maximum lesion overlap in the right Insula.