Institut für Diagnostische Radiologie und Neuroradiologie
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Der Nachweis von demyelinisierenden Läsionen in T2-gewichteten Aufnahmen ist entsprechend der aktuellen Empfehlungen entscheidender diagnostischer Bestandteil für den Nachweis der örtlichen und zeitlichen Dissemination der Erkrankung Multiple Sklerose in der MRT. Hierfür sind ein möglichst optimales SNR und CNR der demyelinisierenden Läsionen in T2-gewichteten Aufnahmen notwendig. Die SPACE-Sequenz stellt im Bereich der Hochfeld-MRT eine alternative Sequenztechnologie dar, welche die SAR-Limitationen der etablierten TSE-Sequenzen umgeht. Ziel der Studie war es, zu zeigen, dass die Darstellung demyelinisierender Läsionen in T2-gewichteten Aufnahmen bei Patienten mit Multipler Sklerose durch die SPACE-Sequenz und die 32-Kanal-Spule sowohl hinsichtlich der objektiven wie auch der subjektiven Bildqualität in der MRT optimiert werden kann. Die statistische Auswertung mittels Wilcoxon Rangsummentest ergab einen signifikanten Zugewinn an SNR und CNR (p< 0,001) sowohl für die Space Sequenz gegenüber der TSE Sequenz unabhängig mit welcher Spulenkombination als auch für die 32-Kanalspule gegenüber der 12-Kanalspule, unabhängig von der Sequenzwahl sowie einen signifikanten Mehrgewinn für die Kombination aus Space-Sequenz und 32-Kanal-Spule. Die qualitative Bewertung durch zwei erfahrene Neuroradiologen und einen MS-kundigen Neurologen auf einer 4-Punkte Skala ergab eine signifikant verbesserte Bildqualität für die 32- Kanal-Spule unabhängig von der Sequenz und keinen signifikanten Unterschied zwischen den Sequenzen Space und TS. In Kombination mit einer 32-Kanal-Kopfspule ermöglicht die SPACE-Sequenz eine Verbesserung der subjektiven Bildqualität sowie von SNR und CNR der demyelinisierenden Läsionen bei Patienten mit Multipler Sklerose.
Purpose: Hyperthermic ablation is a minimally invasive mode of tumour therapy which serves as a viable alternative to surgical intervention. However, one of the major drawbacks, besides the heat sink effect and the risk of damaging adjacent organs, is limited ablation size. The use of a cooling fluid during ablation has been shown to increase the ablation volume and decrease the carbonisation rate. The aim of this study was to investigate whether the composition of the cooling fluid has an effect on ablation size and carbonisation rate during hepatic laser ablation in an ex vivo bovine setting. Method: In this study bovine hepatic tissue was ablated in an ex vivo setting using an internally cooled laser applicator. A total of 45 tissue samples were assigned to three groups: 0.9% saline infusion (n = 15), distilled water infusion (n = 15) and a 50%/50% mixture of 0.9% saline and distilled water (n = 15). Ablation was conducted using a 1064 nm Nd:YAG laser at a wattage of 25 W and time interval of 10 min. The ablation volume and carbonisation rate were then measured and recorded through postprocedural MRI. One-way ANOVA and post-hoc testing were performed to assess the effect of the cooling fluid composition on the ablation volumes. Results: We found that using a mixture of saline and distilled water as a cooling fluid during hyperthermic ablation resulted in a larger ablation volume (mean ± SD: 22.64 ± 0.99 cm3) when compared to saline infusion (21.08 ± 1.11 cm3) or distilled water infusion (20.92 ± 0.92 cm3). This difference was highly significant (p < 0.001). There was no significant difference in ablation size between the saline group and the distilled water group. The highest carbonisation rate occurred in the saline group (12/15), followed by the mixed infusion group (3/15) and the distilled water group (1/15). Conclusions: The results of this study suggest that cooling fluid composition during hepatic laser ablation affects ablation volume in an ex vivo bovine setting. There was no statistically significant difference when comparing ablation volumes during saline infusion and distilled water infusion, but the carbonisation rate was significantly higher when using saline. The combination of saline and distilled water in a 50%/50% mixture as cooling fluid appears to be an auspicious alternative, as ablation volumes created with it are larger when compared to saline and distilled water alone, while carbonisation rate remains low. This might improve patient outcome as well as patient eligibility for hyperthermic ablation.
(1) Background: BPD is characterized by affect dysregulation, interpersonal problems, and disturbances in attachment, but neuroimaging studies investigating attachment representations in BPD are rare. No study has examined longitudinal neural changes associated with interventions targeting these impairments. (2) Methods: We aimed to address this gap by performing a longitudinal neuroimaging study on n = 26 patients with BPD treated with Dialectic Behavioral Therapy (DBT) and n = 26 matched healthy controls (HCs; post intervention point: n = 18 BPD and n = 23 HCs). For functional imaging, we applied an attachment paradigm presenting attachment related scenes represented in drawings paired with related neutral or personalized sentences from one’s own attachment narratives. In a prior cross-sectional investigation, we identified increased fMRI-activation in the human attachment network, in areas related to fear response and the conflict monitoring network in BPD patients. These were especially evident for scenes from the context of loneliness (monadic pictures paired with individual narrative sentences). Here, we tested whether these correlates of attachment representation show a near-to-normal development over one year of DBT intervention. In addition, we were interested in possible associations between fMRI-activation in these regions-of-interest (ROI) and clinical scores. (3) Results: Patients improved clinically, showing decreased symptoms of borderline personality organization (BPI) and increased self-directedness (Temperament and Character Inventory, TCI) over treatment. fMRI-activation was increased in the anterior medial cingulate cortex (aMCC) and left amygdala in BPD patients at baseline which was absent after intervention. When investigating associations between scores (BPI, TCI) and functional activation, we found significant effects in the bilateral amygdala. In contrast, aMCC activation at baseline was negatively associated with treatment outcome, indicating less effective treatment effects for those with higher aMCC activation at baseline. (4) Conclusions: Monadic attachment scenes with personalized sentences presented in an fMRI setup are capable of identifying increased activation magnitude in BPD. After successful DBT treatment, these increased activations tend to normalize which could be interpreted as signs of a better capability to regulate intensive emotions in the context of “social pain” towards a more organized/secure attachment representation. Amygdala activation, however, indicates high correlations with pre-treatment scores; activation in the aMCC is predictive for treatment gain. Functional activation of the amygdala and the aMCC as a response to attachment scenes representing loneness at baseline might be relevant influencing factors for DBT-intervention outcomes.
Die semiautomatische Auswertung in der Schlaganfalldiagnostik hat in den letzten Jahren an Bedeutung gewonnen.
Die Anfertigung einer probabilistischen ASPECTS-Karte des gesamten Media-Stromgebietes über die zwei initialen Schichten der ASPECTS Unterteilung hinaus ist möglich und in der heutigen Zeit bereits als diagnostisches Mittel ein Standard geworden. In dieser Arbeit konnte gezeigt werden, dass eine Normierung der CTs vor Festlegung der ASPECTS-Karte eine genauere Abgrenzbarkeit der Regionen voneinander mit hoher Übereinstimmung in den Randbereichen zur Folge hat. Die klinische Relevanz dieser probabilistischen ASPECTS-Karte wird dadurch verdeutlicht, dass es mittlerweile eine Vielzahl kommerziell verfügbarer Systeme zur semi-automatischen Coregistrierung von CCT-Daten mit einer solchen ASPECTS- Karte gibt. Sie verwenden diese Technik zur Detektion von Infarktfrühzeichen in den einzelnen ASPECTS-Regionen, die eine vergleichbare diagnostische Aussagekraft bieten wie die visuelle Beurteilung [64], [65], [66].
Die Übertragung des CTP-Infarktgebietes auf die von uns angefertigte probabilistischen ASPECTS-Karte war durch technische Limitationen nicht möglich. CT-Scanner der aktuellen Generation würden diese durch Ganzkopfperfusion ohne notwendige Angulation der Gantry erlauben oder die sekundäre Rekonstruktion von Perfusions-CT-Parameterkarten aus einer multiphasischen CT-Angiographie ermöglichen, so dass eine Coregistrierung der Daten nach einer Normalisierung möglich wäre [71], [72], [73].
Die voxelweise Auswertung der Perfusionsparameterkarten bestätigt die in vorherigen Arbeiten mittels ROI-Analyse definierten Schwellenwerte, wenn man bei dem CBV und der MTT den Faktor 10 berücksichtigt. Diese Art der Auswertung zeigt aber auch, dass die in der bisherigen Literatur beschriebenen Grenzwerte als eine Art Kontinuum oder Grenzwertbereich zu verstehen sind, innerhalb dessen die Wahrscheinlichkeit steigt, dass ein Voxel infarziert oder nicht. Dabei spiegelt die voxelweise Auswertung der Perfusions-CT-Daten die komplexen pathophysiologischen Vorgänge im Infarktareal wider und kann auch angiographische Phänomene, die bei der endovaskulären Schlaganfalltherapie beobachtet werden können, visualisieren. Mit zunehmender Computerleistung sollte eine „real time“- voxelweise Auswertung von Parameterkarten der Perfusions-CT zur Entscheidungsfindung diskutiert werden.
In einer klinischen Intervention mittels Schienentherapie mit einer Unterkieferschiene bei Patientinnen mit kraniomandibulärer Dysfunktion zeigte sich eine Reduktion des Bewegungsschmerzen und eine Veränderung der fMRT-Aktivität assoziiert mit der Trait-Angst-Reduktion.
Eine Verminderung der fMRT-Aktivität bei Okklusion in der bilateralen anterioren und
rechten posterioren Insel ging, insbesondere im ersten Zeitintervall der Intervention,
einher mit einer Verminderung der Trait-Angst. Hier zeigen sich unmittelbare Effekte
der Behandlung auf eine pathologisch erhöhte Monitoringaktivität, die mit der erhöhten
Angstmodulation einhergeht. Im späteren Verlauf scheint eher die präfrontale
Aufmerksamkeit auf die Bewegungsdurchführung vermindert zu sein.
Die zeitliche Abfolge mit zunächst einer Minderung in emotional unmittelbar
gekoppelten Prozessen des Bewegungsmonitorings gegenüber der später
einsetzenden Minderung der Aktivität bewusster präfrontaler Prozesse und den damit
einhergehenden Modulationen von Trait-Angst und Schmerz, weist auf grundsätzliche
Mechanismen der Intervention hin.
Neuroblastoma is the most common extracranial, malignant, solid tumor found in children. In more than one-third of cases, the tumor is in an advanced stage, with limited resectability. The treatment options include resection, with or without (neo-/) adjuvant therapy, and conservative therapy, the latter even with curative intent. Contrast-enhanced MRI is used for staging and therapy monitoring. Diffusion-weighted imaging (DWI) is often included. DWI allows for a calculation of the apparent diffusion coefficient (ADC) for quantitative assessment. Histological tumor characteristics can be derived from ADC maps. Monitoring the response to treatment is possible using ADC maps, with an increase in ADC values in cases of a response to therapy. Changes in the ADC value precede volume reduction. The usual criteria for determining the response to therapy can therefore be supplemented by ADC values. While these changes have been observed in neuroblastoma, early changes in the ADC value in response to therapy are less well described. In this study, we evaluated whether there is an early change in the ADC values in neuroblastoma under therapy; if this change depends on the form of therapy; and whether this change may serve as a prognostic marker. We retrospectively evaluated neuroblastoma cases treated in our institution between June 2007 and August 2014. The examinations were grouped as ‘prestaging’; ‘intermediate staging’; ‘final staging’; and ‘follow-up’. A classification of “progress”, “stable disease”, or “regress” was made. For the determination of ADC values, regions of interest were drawn along the borders of all tumor manifestations. To calculate ADC changes (∆ADC), the respective MRI of the prestaging was used as a reference point or, in the case of therapies that took place directly after previous therapies, the associated previous staging. In the follow-up examinations, the previous examination was used as a reference point. The ∆ADC were grouped into ∆ADCregress for regressive disease, ∆ADCstable for stable disease, and ∆ADC for progressive disease. In addition, examinations at 60 to 120 days from the baseline were grouped as er∆ADCregress, er∆ADCstable, and er∆ADCprogress. Any differences were tested for significance using the Mann–Whitney test (level of significance: p < 0.05). In total, 34 patients with 40 evaluable tumor manifestations and 121 diffusion-weighted MRI examinations were finally included. Twenty-seven patients had INSS stage IV neuroblastoma, and seven had INSS stage III neuroblastoma. A positive N-Myc expression was found in 11 tumor diseases, and 17 patients tested negative for N-Myc (with six cases having no information). 26 patients were assigned to the high-risk group according to INRG and eight patients to the intermediate-risk group. There was a significant difference in mean ADC values from the high-risk group compared to those from the intermediate-risk group, according to INRG. The differences between the mean ∆ADC values (absolute and percentage) according to the course of the disease were significant: between ∆ADCregress and ∆ADCstable, between ∆ADCprogress and ∆ADCstable, as well as between ∆ADCregress and ∆ADCprogress. The differences between the mean er∆ADC values (absolute and percentage) according to the course of the disease were significant: between er∆ADCregress and er∆ADCstable, as well as between er∆ADCregress and er∆ADCprogress. Forms of therapy, N-Myc status, and risk groups showed no further significant differences in mean ADC values and ∆ADC/er∆ADC. A clear connection between the ADC changes and the response to therapy could be demonstrated. This held true even within the first 120 days after the start of therapy: an increase in the ADC value corresponds to a probable response to therapy, while a decrease predicts progression. Minimal or no changes were seen in cases of stable disease.
Background
A bidirectional functional link between vestibular and fear-related disorders has been previously suggested.
Objective
To test a potential overlap of vestibular and fear systems with regard to their brain imaging representation maps.
Methods
By use of voxel-based mapping permutation of subject images, we conducted a meta-analysis of earlier functional magnetic resonance imaging (fMRI) studies applying vestibular stimulation and fear conditioning in healthy volunteers.
Results
Common clusters of concordance of vestibular stimulation and fear conditioning were found in the bilateral anterior insula cortex, ventrolateral prefrontal cortex and the right temporal pole, bilaterally in the adjacent ventrolateral prefrontal cortex, cingulate gyrus, secondary somatosensory cortex, superior temporal and intraparietal lobe, supplementary motor area and premotor cortex, as well as subcortical areas, such as the bilateral thalamus, mesencephalic brainstem including the collicular complex, pons, cerebellar vermis and bilateral cerebellar hemispheres. Peak areas of high concordance for activations during vestibular stimulation but deactivations during fear conditioning were centered on the posterior insula and S2.
Conclusions
The structural overlap of both networks allows the following functional interpretations: first, the amygdala, superior colliculi, and antero-medial thalamus might represent a release of preprogramed sensorimotor patterns of approach or avoidance. Second, the activation (vestibular system) and deactivation (fear system) of the bilateral posterior insula is compatible with the view that downregulation of the fear network by acute vestibular disorders or unfamiliar vestibular stimulation makes unpleasant perceived body accelerations less distressing. This also fits the clinical observation that patients with bilateral vestibular loss suffer from less vertigo-related anxiety.
Background and purpose
The insula has important functions in monitoring and integrating physiological responses to a personal experience of multimodal input. The experience of chills in response to auditory stimuli is an important example for a relevant arousing experience coupled with bodily response. A group study about altered chill experiences in patients with insula lesions is lacking.
Methods
Twenty-eight stroke patients with predominantly insula lesions in the chronic stage and 14 age-matched controls were investigated using chill stimuli of both valences (music, harsh sounds). Group differences were analyzed in subjective chill reports, associated bodily responses (skin conductance response), lesion mapping, diffusion-weighted imaging and functional magnetic resonance imaging. Other neuropsychological deficits were excluded by comprehensive testing. Diffusion-weighted imaging was quantified for four insula tracts using fractional anisotropy.
Results
The frequency of chill experiences was comparable between participant groups. However, bodily responses were decreased for the stroke group. Whereas there was no association of lesion location, a positive association was found for the skin conductance response during aversive sounds and the tract connecting anterior inferior insula and left temporal pole in the stroke group. Similarly, functional magnetic resonance imaging activation in areas hypothesized to compensate for damage was increased with bodily response.
Conclusions
A decoupling of felt arousal and bodily response after insula lesion was observed. Impaired bodily response was related to an impaired interaction of the left anterior insula and the temporal pole.
Background
Chronic pain of different aetiologies and localization has been associated with less grey matter volume (GMV) in several cortical and subcortical brain areas. Recent meta-analyses reported low reproducibility of GMV alterations between studies and pain syndromes.
Methods
To investigate GMV in common chronic pain conditions defined by body location (chronic back pain, n = 174; migraine, n = 92; craniomandibular disorder, n = 39) compared to controls (n = 296), we conducted voxel-based morphometry and determined GMV from high-resolution cranial MRIs obtained in an epidemiologic survey. Mediation analyses were performed between the presence of chronic pain and GMV testing the mediators stress and mild depression. The predictability of chronic pain was investigated with binomial logistic regression.
Results
Whole-brain analyses yielded reduced GMV within the left anterior insula and the anterior cingulate cortex, for a ROI approach additionally the left posterior insula and left hippocampus showing less GMV across all patients with chronic pain. The relationship of pain with GMV in the left hippocampus was mediated by self-reported stressors in the last 12 months. Binomial logistic regression revealed a predictive effect for GMV in the left hippocampus and left anterior insula/temporal pole for the presence of chronic pain.
Conclusions
Chronic pain across three different pain conditions was characterized by less GMV in brain regions consistently described for different chronic pain conditions before. Less GMV in the left hippocampus mediated by experienced stress during the last year might be related to altered pain learning mechanisms in chronic pain patients.
Significance
Grey matter reorganization could serve as a diagnostic biomarker for chronic pain. In a large cohort, we here replicated findings of less grey matter volume across three pain conditions in the left anterior and posterior insula, anterior cingulate and left hippocampus. Less hippocampal grey matter was mediated by experienced stress.
Chills are emotional peaks especially in response toward acoustic stimuli. In the present study, we examined facial expressions associated with pleasant and unpleasant chill experiences during music and harsh sounds by measuring electromyographic activity from facial corrugator and zygomatic muscles. A rubber bulb could be pressed by the participants to report chill intensities. During harsh sounds, increased activation of both corrugator and zygomatic muscle was observed. Zygomatic muscle activity was even more pronounced when a chill experience was reported during such sounds. In contrast, pleasant chill experiences during music were associated with slightly increased corrugator activity compared with absent chills. Our data suggest that harsh sounds produce a painful facial expression that is even intensified when a chill experience is reported. Increased corrugator activity during chills toward music might refer to states of being moved. The results are discussed in the light of a proposed role of the chill in regulating social behavior. Our results suggest that recording facial muscle activity can be a valuable method for the examination of pleasant and unpleasant peak emotions induced by acoustic stimuli.