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1.
Addict Biol ; 27(1): e13083, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34363643

RESUMEN

Tobacco smoking is one of the leading causes of preventable death and disease worldwide. Most smokers want to quit, but relapse rates are high. To improve current smoking cessation treatments, a better understanding of the underlying mechanisms of nicotine dependence and related craving behaviour is needed. Studies on cue-driven cigarette craving have been a particularly useful tool for investigating the neural mechanisms of drug craving. Here, functional neuroimaging studies in humans have identified a core network of craving-related brain responses to smoking cues that comprises of amygdala, anterior cingulate cortex, orbitofrontal cortex, posterior cingulate cortex and ventral striatum. However, most functional Magnetic Resonance Imaging (fMRI) cue-reactivity studies do not adjust their stimuli for emotional valence, a factor assumed to confound craving-related brain responses to smoking cues. Here, we investigated the influence of emotional valence on key addiction brain areas by disentangling craving- and valence-related brain responses with parametric modulators in 32 smokers. For one of the suggested key regions for addiction, the amygdala, we observed significantly stronger brain responses to the valence aspect of the presented images than to the craving aspect. Our results emphasize the need for carefully selecting stimulus material for cue-reactivity paradigms, in particular with respect to emotional valence. Further, they can help designing future research on teasing apart the diverse psychological dimensions that comprise nicotine dependence and, therefore, can lead to a more precise mapping of craving-associated brain areas, an important step towards more tailored smoking cessation treatments.


Asunto(s)
Encéfalo/fisiopatología , Ansia/fisiología , Señales (Psicología) , Cese del Hábito de Fumar , Fumar/fisiopatología , Tabaquismo/fisiopatología , Adulto , Conducta Adictiva/fisiopatología , Mapeo Encefálico , Femenino , Neuroimagen Funcional , Giro del Cíngulo/fisiopatología , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Fumadores/psicología , Síndrome de Abstinencia a Sustancias/fisiopatología , Adulto Joven
2.
J Neuroradiol ; 49(1): 9-16, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34023361

RESUMEN

INTRODUCTION: In patients with ulnar neuropathy at the elbow (UNE) the precise determination of the site of lesion is important for subsequent differential diagnostic considerations and therapeutic management. Due to a paucity of comparable data, to better define the role of different diagnostic tests, we performed the first prospective study comparing the diagnostic accuracy of short segment nerve stimulation, nerve ultrasonography, MR neurography (MRN), and diffusion tensor imaging (DTI) in patients with UNE. METHODS: UNE was clinically diagnosed in 17 patients with 18 affected elbows. For all 18 affected elbows in patients and 20 elbows in 10 healthy volunteers, measurements of all different diagnostic tests were performed at six anatomical positions across the elbow with measuring points from distal (D4) to proximal (P6) in relation to the medial epicondyle (P0). Additional qualitative assessment regarding structural changes of surrounding nerve anatomy was conducted. RESULTS: The difference between affected arms of patients and healthy control arms were most frequently the largest at measure intervals D2 to P0 and P0 to P2 for electrophysiological testing, or measure points P0 and P2 for all other devices, respectively. At both levels P0 and at P2, T2 contrast-to-noise ratio (CNR) of MRN and mean diffusivity (MD) of DTI-based MRN showed best accuracies. DISCUSSION: This study revealed differences in diagnostic performance of tests concerning a specific location of UNE, with better results for T2 contrast to noise ratio (CNR) in MRN and mean diffusivity of DTI-based MRN. Additional testing with MRN and nerve ultrasonography is recommended to uncover anatomical changes.


Asunto(s)
Codo , Neuropatías Cubitales , Imagen de Difusión Tensora , Codo/diagnóstico por imagen , Electrodiagnóstico , Humanos , Conducción Nerviosa , Estudios Prospectivos , Nervio Cubital , Neuropatías Cubitales/diagnóstico por imagen
3.
Eur Addict Res ; 27(2): 107-114, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-32854096

RESUMEN

BACKGROUND: Cue-reactivity paradigms provide valuable insights into the underlying mechanisms of nicotine craving in nicotine-dependent subjects. In order to study cue-driven nicotine craving, robust and validated stimulus datasets are essential. OBJECTIVES: The aim of this study was to generate and validate a large set of individually rated smoking-related cues that allow for assessment of different stimulus intensities along the dimensions craving, valence, and arousal. METHODS: The image database consisted of 330 visual cues. Two hundred fifty smoking-associated pictures (Creative Commons license) were chosen from online databases and showed a widespread variety of smoking-associated content. Eighty pictures from previously published databases were included for cross-validation. Forty volunteers with tobacco use disorder rated "urge-to-smoke," "valence," and "arousal" for all images on a 100-point visual analogue scale. Pictures were also labelled according to 18 categories such as lit/unlit cigarettes in mouth, cigarette end, and cigarette in ashtray. RESULTS: Ratings (mean ± SD) were as follows: urge to smoke, 44.9 ± 13.2; valence, 51.2 ± 7.6; and arousal, 54.6 ± 7.1. All ratings, particularly "urge to smoke," were widely distributed along the whole scale spectrum. CONCLUSIONS: We present a novel image library of well-described smoking-related cues, which were rated on a continuous scale along the dimensions craving, valence, and arousal that accounts for inter-individual differences. The rating software, image database, and their ratings are publicly available at https://smocuda.github.io.


Asunto(s)
Señales (Psicología) , Tabaquismo , Ansia , Humanos , Nicotina , Fumar
4.
Psychol Med ; 50(6): 936-947, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-30994080

RESUMEN

BACKGROUND: Bipolar disorder I (BD-I) is defined by episodes of mania, depression and euthymic states. These episodes are among other symptoms characterized by altered reward processing and negative symptoms (NS), in particular apathy. However, the neural correlates of these deficits are not well understood. METHODS: We first assessed the severity of NS in 25 euthymic BD-I patients compared with 25 healthy controls (HC) and 27 patients with schizophrenia (SZ). Then, we investigated ventral (VS) and dorsal striatal (DS) activation during reward anticipation in a Monetary Incentive Delayed Task and its association with NS. RESULTS: In BD-I patients NS were clearly present and the severity of apathy was comparable to SZ patients. Apathy scores in the BD-I group but not in the SZ group correlated with sub-syndromal depression scores. At the neural level, we found significant VS and DS activation in BD-I patients and no group differences with HC or SZ patients. In contrast to patients with SZ, apathy did not correlate with striatal activation during reward anticipation. Explorative whole-brain analyses revealed reduced extra-striatal activation in BD-I patients compared with HC and an association between reduced activation of the inferior frontal gyrus and apathy. CONCLUSION: This study found that in BD-I patients apathy is present to an extent comparable to SZ, but is more strongly related to sub-syndromal depressive symptoms. The findings support the view of different pathophysiological mechanisms underlying apathy in the two disorders and suggest that extra-striatal dysfunction may contribute to impaired reward processing and apathy in BD-I.


Asunto(s)
Apatía/fisiología , Trastorno Bipolar/fisiopatología , Trastornos Disociativos/fisiopatología , Recompensa , Esquizofrenia/fisiopatología , Adulto , Trastorno Bipolar/diagnóstico por imagen , Encéfalo/fisiopatología , Mapeo Encefálico , Trastornos Disociativos/diagnóstico por imagen , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Motivación , Neostriado/diagnóstico por imagen , Neostriado/fisiopatología , Corteza Prefrontal/fisiopatología , Esquizofrenia/diagnóstico por imagen , Psicología del Esquizofrénico , Estriado Ventral/diagnóstico por imagen , Estriado Ventral/fisiopatología , Adulto Joven
5.
Brain ; 141(9): 2806-2819, 2018 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-30169587

RESUMEN

Adaptive coding of information is a fundamental principle of brain functioning. It allows for efficient representation over a large range of inputs and thereby alleviates the limited coding range of neurons. In the present study, we investigated for the first time potential alterations in context-dependent reward adaptation and its association with symptom dimensions in the schizophrenia spectrum. We studied 27 patients with first-episode psychosis, 26 individuals with schizotypal personality traits and 25 healthy controls. We used functional MRI in combination with a variant of the monetary incentive delay task and assessed adaptive reward coding in two reward conditions with different reward ranges. Compared to healthy controls, patients with first-episode psychosis and healthy individuals with schizotypal personality traits showed a deficit in increasing the blood oxygen level-dependent response slope in the right caudate for the low reward range compared to the high reward range. In other words, the two groups showed inefficient neural adaptation to the current reward context. In addition, we found impaired adaptive coding of reward in the caudate nucleus and putamen to be associated with total symptom severity across the schizophrenia spectrum. Symptom severity was more strongly associated with neural deficits in adaptive coding than with the neural coding of absolute reward outcomes. Deficits in adaptive coding were prominent across the schizophrenia spectrum and even detectable in unmedicated (healthy) individuals with schizotypal personality traits. Furthermore, the association between total symptom severity and impaired adaptive coding in the right caudate and putamen suggests a dimensional mechanism underlying imprecise neural adaptation. Our findings support the idea that impaired adaptive coding may be a general information-processing deficit explaining disturbances within the schizophrenia spectrum over and above a simple model of blunted absolute reward signals.


Asunto(s)
Adaptación Psicológica/fisiología , Trastornos Psicóticos/fisiopatología , Esquizofrenia/fisiopatología , Adulto , Núcleo Caudado/fisiopatología , Trastornos del Conocimiento/diagnóstico , Trastornos del Conocimiento/fisiopatología , Dopamina/metabolismo , Dopamina/fisiología , Procesamiento Automatizado de Datos/métodos , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Motivación , Neuropsiquiatría/métodos , Pruebas Neuropsicológicas , Trastornos Psicóticos/metabolismo , Recompensa , Trastorno de la Personalidad Esquizotípica/metabolismo , Trastorno de la Personalidad Esquizotípica/fisiopatología
6.
Skeletal Radiol ; 47(10): 1393-1402, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29687149

RESUMEN

OBJECTIVE: We aimed to provide mean values for fat-fraction and volume for full-length bilateral rotator cuff and deltoid muscles in asymptomatic adults selected on the basis of their good musculoskeletal and systemic health, and to understand the influence of gender, age, and arm dominance. MATERIALS AND METHODS: Seventy-six volunteers aged 20 to 60 years who were screened for normal BMI and high general health were included in the study. MRI was performed at 3 Tesla using three-point DIXON sequences. Volume and fat-signal fraction of the rotator cuff muscles and the deltoid muscle were determined with semi-automated segmentation of entire muscle lengths. Differences according to age, gender, and handedness per muscle were evaluated. RESULTS: Fat-signal fractions were comparable between genders (mean ± 2 SD, 95% CI, women 7.0 ± 3.0; 6.8-7.2%, men 6.8 ± 2.7; 6.7-7.0%) but did not show convincing changes with age. Higher shoulder muscle volume and lower fat-signal fraction in the dominant arm were shown for teres minor and deltoid (p < 0.01) with similar trends shown for the other rotator cuff muscles. CONCLUSIONS: Bilateral fat-signal fractions and volumes based on entire length shoulder muscles in asymptomatic 20-60 year old adults may provide reference for clinicians. Differences shown according to arm dominance should be considered and may rationalize the need for bilateral imaging in determining appropriate management.


Asunto(s)
Tejido Adiposo/diagnóstico por imagen , Músculo Deltoides/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Manguito de los Rotadores/diagnóstico por imagen , Hombro/diagnóstico por imagen , Tejido Adiposo/anatomía & histología , Adulto , Factores de Edad , Estudios Transversales , Músculo Deltoides/anatomía & histología , Femenino , Lateralidad Funcional , Voluntarios Sanos , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Manguito de los Rotadores/anatomía & histología , Lesiones del Manguito de los Rotadores , Hombro/anatomía & histología , Suiza , Adulto Joven
7.
Br J Psychiatry ; 210(1): 75-82, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-26892851

RESUMEN

BACKGROUND: In patients with schizophrenia in a psychotic episode, intra-striatal intrinsic connectivity is increased in the putamen but not ventral striatum. Furthermore, multimodal changes have been observed in the anterior insula that interact extensively with the putamen. AIMS: We hypothesised that during psychosis, putamen extra-striatal functional connectivity is altered with both the anterior insula and areas normally connected with the ventral striatum (i.e. altered functional connectivity distinctiveness of putamen and ventral striatum). METHOD: We acquired resting-state functional magnetic resonance images from 21 patients with schizophrenia in a psychotic episode and 42 controls. RESULTS: Patients had decreased functional connectivity: the putamen with right anterior insula and dorsal prefrontal cortex, the ventral striatum with left anterior insula. Decreased functional connectivity between putamen and right anterior insula was specifically associated with patients' hallucinations. Functional connectivity distinctiveness was impaired only for the putamen. CONCLUSIONS: Results indicate aberrant extra-striatal connectivity during psychosis and a relationship between reduced putamen-right anterior insula connectivity and hallucinations. Data suggest that altered intrinsic connectivity links striatal and insular pathophysiology in psychosis.


Asunto(s)
Corteza Cerebral/fisiopatología , Conectoma/métodos , Alucinaciones/fisiopatología , Trastornos Psicóticos/fisiopatología , Putamen/fisiopatología , Esquizofrenia/fisiopatología , Estriado Ventral/fisiopatología , Adulto , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad
8.
J Magn Reson Imaging ; 45(2): 570-578, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-27434166

RESUMEN

PURPOSE: To demonstrate the feasibility of intravoxel incoherent motion imaging (IVIM) for quantification of perfusion changes in the parotid gland after gustatory stimulation. MATERIALS AND METHODS: Eight healthy volunteers underwent diffusion-weighted magnetic resonance imaging (MRI) of the neck at 3T with 11 dynamic acquisitions (9 b-values between 0 and 980 s/mm2 , 2:40 min each). After 5:20 minutes, a lemon-mint-drop was administered orally. Perfusion fraction (Fp ), pseudodiffusion (D*), tissue diffusion (Dt ) coefficients, and optimal b-value threshold were measured using a multistep variable b-value threshold fitting approach. Dynamic changes in the coefficients between three exemplary timepoints (baseline, after stimulation, after dissolution) were compared using a Mann-Whitney U-test with Bonferroni correction (P < 0.016 significance level). RESULTS: Mean values (95% confidence interval [CI]) for IVIM parameters at baseline were Fp : 0.11 (0.08-0.15), D*: 56.48 mm2 /s (39.71-98.27), Dt : 1.01 mm2 /s (0.84-1.06), b-value threshold: 30 s/mm2 (21.25-105). After stimulation: Fp 0.16 (0.15-0.24; P < 0.01), D* 93.83 mm2 /s (77.98-129.53, P = 0.25), Dt 0.93 mm2 /s (0.87-1.08, P = 0.94), b-value threshold 20 s/mm2 (13.75-26.25 s/mm2 , P = 0.10), reflecting the increase in tissue perfusion. After dissolution of the drop: Fp : 0.13 (0.11-0.18, P = 0.38), D*: 101.61 mm2 /s (90.68-144.55, P = 0.07), Dt : 0.91 mm2 /s (0.85-1.05, P = 0.64), b-value threshold: 15 s/mm2 (11.25-40, P = 0.38). CONCLUSION: The IVIM method allows for simultaneous quantification of changes in perfusion and diffusion effects after gustatory stimulation of the parotid gland. LEVEL OF EVIDENCE: 2 J. Magn. Reson. Imaging 2017;45:570-578.


Asunto(s)
Velocidad del Flujo Sanguíneo/fisiología , Interpretación de Imagen Asistida por Computador/métodos , Imagenología Tridimensional/métodos , Angiografía por Resonancia Magnética/métodos , Glándula Parótida/diagnóstico por imagen , Glándula Parótida/fisiología , Percepción del Gusto/fisiología , Adulto , Estudios de Factibilidad , Femenino , Humanos , Aumento de la Imagen/métodos , Masculino , Persona de Mediana Edad , Movimiento (Física) , Movimiento/fisiología , Glándula Parótida/irrigación sanguínea , Proyectos Piloto , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Adulto Joven
9.
J Magn Reson Imaging ; 46(3): 663-677, 2017 09.
Artículo en Inglés | MEDLINE | ID: mdl-28067973

RESUMEN

PURPOSE: To assess the feasibility of diffusion tensor imaging (DTI) using simultaneous multislice (SMS) acquisition with blipped controlled aliasing in parallel imaging (CAIPI) for accelerated readout-segmented echo planar imaging (rs-EPI) of the mandibular nerves. DTI of the mandibular nerves using EPI is challenging due to susceptibility artifacts. Rs-EPI is less prone to artifacts but associated with longer scan durations. MATERIALS AND METHODS: Eight asymptomatic volunteers were imaged at 3T using a 64-channel head/neck coil. Conventional, 2-fold (2xSMS) and 3-fold (3xSMS) slice-accelerated rs-EPI sequences were acquired. Tractography of the mandibular nerves was performed. Signal-to-noise ratio (SNR), fractional anisotropy (FA), mean diffusivity (MD), and number of tracts were calculated. Artifacts were evaluated qualitatively on Likert scales. Parameters were compared statistically. Clinical feasibility of 2xSMS rs-EPI was tested in four patients. RESULTS: SNR was similar for conventional (mean ± SD; 8.55 ± 3.90) and 2xSMS rs-EPI (7.83 ± 3.15) but lower for 3xSMS rs-EPI (5.42 ± 2.93; analysis of variance, P = 0.004). FA was similar for all sequences (rs-EPI, 0.42 ± 0.08; 2xSMS rs-EPI, 0.43 ± 0.08; 3xSMS rs-EPI, 0.44 ± 0.06), while 3xSMS rs-EPI showed lower MD (rs-EPI, 0.0015 ± 0.0003; 2xSMS rs-EPI, 0.0014 ± 0.0001; 3xSMS rs-EPI, 0.0013 ± 0.0003) and lower number of tracts (rs-EPI, 66.56 ± 51.31; 2xSMS rs-EPI, 65.75 ± 55.40; 3xSMS rs-EPI, 37.93 ± 52.42) compared to rs-EPI and 2xSMS rs-EPI. Additionally, 2xSMS rs-EPI was feasible in four clinical patients and provided robust imaging results. CONCLUSION: 2xSMS rs-EPI yielded similar SNR, FA, and MD values compared to conventional rs-EPI at reduced scan time and is feasible in clinical patients. These findings suggest the potential clinical applicability of rs-EPI for DTI of the mandibular nerve. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:663-677.


Asunto(s)
Imagen de Difusión Tensora/métodos , Imagen Eco-Planar/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Nervio Mandibular/diagnóstico por imagen , Adulto , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Adulto Joven
10.
Eur Radiol ; 27(1): 393-403, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27097792

RESUMEN

OBJECTIVES: To determine the association between traumatic bone marrow abnormalities, the knee injury mechanism, and associated soft tissue injuries in a larger cohort than those in the published literature. METHOD: Retrospective study including 220 patients with traumatic knee injuries. Knee MRIs were evaluated for trauma mechanism, soft tissue injury, and the location of bone marrow abnormalities. The locations of the abnormalities were correlated with trauma mechanisms and soft tissue injuries using the chi-square test with Bonferroni correction. RESULTS: One hundred and forty-four valgus injuries, 39 pivot shift injuries, 25 lateral patellar dislocations, 8 hyperextensions, and 4 dashboard injuries were included. Valgus and pivot shift injuries showed traumatic bone marrow abnormalities in the posterolateral regions of the tibia. Abnormalities after patellar dislocation were found in the anterolateral and centrolateral femur and patella. Hyperextension injuries were associated with abnormalities in almost all regions, and dashboard injuries were associated with changes in the anterior regions of the tibia and femur. CONCLUSIONS: Our study provides evidence of associations between traumatic bone marrow abnormality patterns and different trauma mechanisms in acute knee injury, and reveals some overlap, especially of the two most common trauma mechanisms (valgus and pivot shift), in a large patient cohort. KEY POINTS: • Specific bone marrow oedema patterns after knee trauma were confirmed. • New associations between bone marrow oedema patterns and knee trauma were shown. • Bone marrow oedema patterns help in identifying associated soft tissue injuries.


Asunto(s)
Médula Ósea/diagnóstico por imagen , Médula Ósea/lesiones , Traumatismos de la Rodilla/complicaciones , Traumatismos de la Rodilla/diagnóstico por imagen , Articulación de la Rodilla/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Adulto Joven
11.
Ann Plast Surg ; 78(1): 67-72, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27801698

RESUMEN

The primary goal of the surgical treatment of upper brachial plexus injuries is to restore active elbow flexion. Accordingly, Oberlin's transfer has been frequently performed since 1994 and has influenced the development of other nerve transfers. However, the window of opportunity for nerve transfers remains a subject of controversy. The objective of this study was to assess magnetic resonance (MR) neurographic, clinical and electrophysiological long-term results after Oberlin's transfer. For this purpose, we performed a retrospective follow-up study. Six patients with upper brachial plexus or musculocutaneous nerve injuries were assessed; 2 were iatrogenic nerve injuries following shoulder arthroscopy or neurofibroma resection. Direct and indirect signs of neuropathy were objectified with MR neurography. Moreover, clinical and electrodiagnostic follow-up was performed and all patients completed the Disabilities of Arm, Shoulder and Hand score. Mean follow-up was 48 ± 21.9 (range, 20-73) months. Mean age was 40 ± 11.3 years and mean delay to surgery was 9 ± 3.2 months. All patients were satisfied with the functional results and the median Disabilities of Arm, Shoulder and Hand score was 21 (range, 1-57). Biceps strength was improved in 5 patients from Medical Research Council grade M0 to M4-5 and in one patient to M2-3. The donor nerve showed normal motor and sensory action potentials. Follow-up MR neurography demonstrated biceps reinnervation. Taken together, this study reports good long-term results after Oberlin's transfer. MR neurography represents an excellent, noninvasive preoperative planning tool and can be of high value in selected postoperative cases. The combined evaluation of nerves and muscles may help to indicate nerve transfers in delayed cases.


Asunto(s)
Plexo Braquial/lesiones , Imagen por Resonancia Magnética , Transferencia de Nervios/métodos , Traumatismos de los Nervios Periféricos/cirugía , Adulto , Plexo Braquial/diagnóstico por imagen , Plexo Braquial/fisiopatología , Plexo Braquial/cirugía , Electromiografía , Femenino , Estudios de Seguimiento , Músculos Isquiosurales/inervación , Músculos Isquiosurales/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Traumatismos de los Nervios Periféricos/diagnóstico por imagen , Traumatismos de los Nervios Periféricos/fisiopatología , Estudios Retrospectivos , Resultado del Tratamiento
12.
J Magn Reson Imaging ; 44(2): 393-400, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-26854879

RESUMEN

PURPOSE: Panoramical radiographs or cone-beam computed tomography (CT) are the standard-of-care in dental imaging to assess teeth, mandible, and mandibular canal pathologies, but do not allow assessment of the inferior alveolar nerve itself nor of its branches. We propose a new technique for "MR neurographic orthopantomograms" exploiting ultrashort echo-time (UTE) imaging of bone and teeth complemented with high-resolution morphological and functional MR neurography. MATERIALS AND METHODS: The Institutional Review Board approved the study in 10 healthy volunteers. Imaging of the subjects mandibles at 3.0T (Magnetom Skyra, Siemens-Healthcare) using a 64-channel head coil with isotropic spatial resolution for subsequent multiplanar reformatting, was performed. Bone images were acquired using a 3D PETRA sequence (TE, 0.07 msec). Morphological nerve imaging was performed using a dedicated 3D PSIF and 3D SPACE STIR sequence. Functional MR neurography was accomplished using a new accelerated diffusion-tensor-imaging (DTI) prototype sequence (2D SMS-accelerated RESOLVE). Qualitative and quantitative image analysis was performed and descriptive statistics are provided. RESULTS: Image acquisition and subsequent postprocessing into the MR neurographic orthopantomogram by overlay of morphological and functional images were feasible in all 10 volunteers without artifacts. All mandibular bones and mandibular nerves were assessable and considered normal. Fiber tractography with quantitative evaluation of physiological diffusion properties of mandibular nerves yielded the following mean ± SD values: fractional anisotropy, 0.43 ± 0.07; mean diffusivity (mm(2) /s), 0.0014 ± 0.0002; axial diffusivity, 0.0020 ± 0.0002, and radial diffusivity, 0.0011 ± 0.0001. CONCLUSION: The proposed technique of MR neurographic orthopantomogram exploiting UTE imaging complemented with high-resolution morphological and functional MR neurography was feasible and allowed comprehensive assessment of osseous texture and neural microarchitecture in a single examination. J. Magn. Reson. Imaging 2016;44:393-400.


Asunto(s)
Imagen por Resonancia Magnética/métodos , Mandíbula/diagnóstico por imagen , Mandíbula/inervación , Neuroimagen/métodos , Radiografía Panorámica/métodos , Diente/diagnóstico por imagen , Diente/inervación , Adulto , Estudios de Factibilidad , Femenino , Humanos , Aumento de la Imagen/métodos , Interpretación de Imagen Asistida por Computador/métodos , Imagenología Tridimensional/métodos , Masculino , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Procesamiento de Señales Asistido por Computador
13.
Eur Radiol ; 26(6): 1921-8, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26373759

RESUMEN

PURPOSE: To investigate the feasibility of MR diffusion tensor imaging (DTI) of the median nerve using simultaneous multi-slice echo planar imaging (EPI) with blipped CAIPIRINHA. MATERIALS AND METHODS: After federal ethics board approval, MR imaging of the median nerves of eight healthy volunteers (mean age, 29.4 years; range, 25-32) was performed at 3 T using a 16-channel hand/wrist coil. An EPI sequence (b-value, 1,000 s/mm(2); 20 gradient directions) was acquired without acceleration as well as with twofold and threefold slice acceleration. Fractional anisotropy (FA), mean diffusivity (MD) and quality of nerve tractography (number of tracks, average track length, track homogeneity, anatomical accuracy) were compared between the acquisitions using multivariate ANOVA and the Kruskal-Wallis test. RESULTS: Acquisition time was 6:08 min for standard DTI, 3:38 min for twofold and 2:31 min for threefold acceleration. No differences were found regarding FA (standard DTI: 0.620 ± 0.058; twofold acceleration: 0.642 ± 0.058; threefold acceleration: 0.644 ± 0.061; p ≥ 0.217) and MD (standard DTI: 1.076 ± 0.080 mm(2)/s; twofold acceleration: 1.016 ± 0.123 mm(2)/s; threefold acceleration: 0.979 ± 0.153 mm(2)/s; p ≥ 0.074). Twofold acceleration yielded similar tractography quality compared to standard DTI (p > 0.05). With threefold acceleration, however, average track length and track homogeneity decreased (p = 0.004-0.021). CONCLUSION: Accelerated DTI of the median nerve is feasible. Twofold acceleration yields similar results to standard DTI. KEY POINTS: • Standard DTI of the median nerve is limited by its long acquisition time. • Simultaneous multi-slice acquisition is a new technique for accelerated DTI. • Accelerated DTI of the median nerve yields similar results to standard DTI.


Asunto(s)
Imagen de Difusión por Resonancia Magnética/métodos , Imagen de Difusión Tensora/métodos , Imagen Eco-Planar/métodos , Nervio Mediano/diagnóstico por imagen , Adulto , Anisotropía , Femenino , Voluntarios Sanos , Humanos , Masculino
14.
Cereb Cortex ; 25(12): 4678-88, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24996404

RESUMEN

Amyloid-ß pathology (Aß) and impaired cognition characterize Alzheimer's disease (AD); however, neural mechanisms that link Aß-pathology with impaired cognition are incompletely understood. Large-scale intrinsic connectivity networks (ICNs) are potential candidates for this link: Aß-pathology affects specific networks in early AD, these networks show disrupted connectivity, and they process specific cognitive functions impaired in AD, like memory or attention. We hypothesized that, in AD, regional changes of ICNs, which persist across rest- and cognitive task-states, might link Aß-pathology with impaired cognition via impaired intrinsic connectivity. Pittsburgh compound B (PiB)-positron emission tomography reflecting in vivo Aß-pathology, resting-state fMRI, task-fMRI, and cognitive testing were used in patients with prodromal AD and healthy controls. In patients, default mode network's (DMN) functional connectivity (FC) was reduced in the medial parietal cortex during rest relative to healthy controls, relatively increased in the same region during an attention-demanding task, and associated with patients' cognitive impairment. Local PiB-uptake correlated negatively with DMN connectivity. Importantly, corresponding results were found for the right lateral parietal region of an attentional network. Finally, structural equation modeling confirmed a direct influence of DMN resting-state FC on the association between Aß-pathology and cognitive impairment. Data provide evidence that disrupted intrinsic network connectivity links Aß-pathology with cognitive impairment in early AD.


Asunto(s)
Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/psicología , Péptidos beta-Amiloides/metabolismo , Cognición/fisiología , Disfunción Cognitiva/metabolismo , Disfunción Cognitiva/psicología , Anciano , Anciano de 80 o más Años , Compuestos de Anilina , Atención/fisiología , Mapeo Encefálico , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Tomografía de Emisión de Positrones , Tiazoles
15.
Skeletal Radiol ; 45(4): 465-74, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26739300

RESUMEN

OBJECTIVE: To determine normative values for volume and fat content of the gluteus medius (GMed) and minimus (GMin) muscle in healthy volunteers and to evaluate their dependence on age, gender and leg dominance. MATERIALS AND METHODS: The IRB approval was obtained for this study. 80 healthy volunteers (females, 40; males, 40; age range 20-62 years), divided into four age groups, were included. Fat- and water-signal-separated MR images of the pelvis were acquired on a 3.0 T MR with a 3-point mDIXON sequence. Normalized volume and fat-signal fraction (FSF) of the GMed (ViGMed, FSFGMed) and GMin (ViGMin, FSFGMin) muscles were determined. RESULTS: The overall mean volumes (normalized) and FSF ± SD: ViGMed 105.13 ± 16.30 cm(3); ViGMin 30.24 ± 5.15 cm(3); FSFGMed 8.13 ± 1.70 % and FSFGMin 9.89 ± 2.72 %. Comparing different age subgroups within each gender no significant differences were found concerning the volumes and FSFs (except FSFGMin in male subgroup aged 20-29 versus 50-62 years, P = 0.014). Comparing FSFs differences between the two genders, only in 20-29 years subgroup, FSFGMed (P =0.003) and FSFGMin (P =0.002) were greater in female. Volume differences between the two legs were not significant (P > 0.077); FSFGMed and FSFGMin (P =0.005 for both) were significantly lower in the dominant leg in female but not in male group (P = 0.454 for FSFGMed and P = 0.643 for FSFMin). CONCLUSION: No age dependency was evident for volume normative data for GMed and GMin and normative data for FSF values showed no age- or gender dependency.


Asunto(s)
Tejido Adiposo/anatomía & histología , Cadera/anatomía & histología , Imagen por Resonancia Magnética/métodos , Músculo Esquelético/anatomía & histología , Tejido Adiposo/diagnóstico por imagen , Adulto , Femenino , Voluntarios Sanos , Cadera/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Músculo Esquelético/diagnóstico por imagen , Valores de Referencia
16.
Eur Radiol ; 25(12): 3499-507, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25903718

RESUMEN

OBJECTIVE: To evaluate whether imaging of the trunk could be omitted in patients with inflammatory myopathies without losing diagnostic accuracy using a restricted whole-body magnetic resonance imaging (rWB-MRI) protocol. METHODS: After approval by the institutional review board, this study was performed in 63 patients (male/female, 13/50; median age, 52 years; range, 20-81 years) with new-onset myopathic symptoms (group 1, n = 41) or previously diagnosed inflammatory myopathy (group 2, n = 22). After performing whole-body MRI (WB-MRI) at 3.0 Tesla, myositis and fatty atrophy were evaluated in different muscles by two independent radiologists. The intra-class correlation coefficient (ICC) was calculated to evaluate inter-observer reliability. RESULTS: Acquisition time was 56:01 minutes for WB-MRI and 37:37 minutes (32.8 % shorter) for rWB-MRI. In group 1, 14 patients were diagnosed with inflammatory myopathy based on muscle biopsy. rWB-MRI and WB-MRI showed equal sensitivity (42.9 %) and specificity (100 %) for myositis, and showed equal sensitivity (71.4 %) and similar specificity (63.0 % and 48.1 %, respectively) for fatty atrophy. No myositis was found in the body trunk in any patient. Inter-observer reliability was between substantial and perfect (ICC, 0.77-1.00). CONCLUSIONS: rWB-MRI showed diagnostic accuracy similar to WB-MRI for inflammatory myopathy at markedly reduced overall acquisition time. KEY POINTS: • Whole-body MRI (WB-MRI) is a time-consuming imaging modality. • A shortened MRI protocol was evaluated for inflammatory myopathies. • The proposed protocol showed diagnostic accuracy similar to WB-MRI.


Asunto(s)
Imagen por Resonancia Magnética/métodos , Miositis/patología , Tórax/patología , Imagen de Cuerpo Entero/métodos , Adulto , Anciano , Anciano de 80 o más Años , Biopsia , Femenino , Humanos , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Adulto Joven
17.
Brain ; 137(Pt 2): 598-609, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24163276

RESUMEN

In major depressive disorder, depressive episodes reoccur in ∼60% of cases; however, neural mechanisms of depressive relapse are poorly understood. Depressive episodes are characterized by aberrant topology of the brain's intrinsic functional connectivity network, and the number of episodes is one of the most important predictors for depressive relapse. In this study we hypothesized that specific changes of the topology of intrinsic connectivity interact with the course of episodes in recurrent depressive disorder. To address this hypothesis, we investigated which changes of connectivity topology are associated with the number of episodes in patients, independently of current symptoms and disease duration. Fifty subjects were recruited including 25 depressive patients (two to 10 episodes) and 25 gender- and age-matched control subjects. Resting-state functional magnetic resonance imaging, Harvard-Oxford brain atlas, wavelet-transformation of atlas-shaped regional time-series, and their pairwise Pearson's correlation were used to define individual connectivity matrices. Matrices were analysed by graph-based methods, resulting in outcome measures that were used as surrogates of intrinsic network topology. Topological scores were subsequently compared across groups, and, for patients only, related with the number of depressive episodes and current symptoms by partial correlation analysis. Concerning the whole brain connectivity network of patients, small-world topology was preserved but global efficiency was reduced and global betweenness-centrality increased. Aberrant nodal efficiency and centrality of regional connectivity was found in the dorsal striatum, inferior frontal and orbitofrontal cortex as well as in the occipital and somatosensory cortex. Inferior frontal changes were associated with current symptoms, whereas aberrant right putamen network topology was associated with the number of episodes. Results were controlled for effects of total grey matter volume, medication, and total disease duration. This finding provides first evidence that in major depressive disorder aberrant topology of the right putamen's intrinsic connectivity pattern is associated with the course of depressive episodes, independently of current symptoms, medication status and disease duration. Data suggest that the reorganization of striatal connectivity may interact with the course of episodes in depression thereby contributing to depressive relapse risk.


Asunto(s)
Mapeo Encefálico/métodos , Cuerpo Estriado/patología , Trastorno Depresivo Mayor/patología , Red Nerviosa/patología , Adulto , Trastorno Depresivo Mayor/psicología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Vías Nerviosas/patología , Factores de Tiempo
18.
J Neuropsychiatry Clin Neurosci ; 26(2): 150-4, 2014 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-24276850

RESUMEN

Subcortical ischemic vascular disease (SIVD) is characterized by extensive white-matter lesions and lacunar infarcts in deep gray matter. The aim of this study was to investigate patterns of cognitive impairment in patients with SIVD. In a retrospective analysis, the authors compared the cognitive performance of 58 patients meeting MRI-defined criteria for SIVD (26 women; 47.3%) with age- and gender-matched control subjects. SIVD patients showed impairments in measures of verbal fluency, verbal memory, speed of cognitive processing, and divided attention. There were no significant differences in constructional praxis, figurative memory, verbal recognition memory, or semantic processing.


Asunto(s)
Trastornos Cerebrovasculares/complicaciones , Trastornos del Conocimiento/etiología , Anciano , Anciano de 80 o más Años , Análisis de Varianza , Trastornos del Conocimiento/clasificación , Registros Electrónicos de Salud/estadística & datos numéricos , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Valores de Referencia , Estudios Retrospectivos
19.
J Psychiatr Res ; 145: 263-275, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-33187692

RESUMEN

BACKGROUND: Avolition and anhedonia are common symptoms in schizophrenia and are related to poor long-term prognosis. There is evidence for aberrant cortico-striatal function and connectivity as neural substrate of avolition and anhedonia. However, it remains unclear how both relate to shared or distinct striatal coupling with large-scale intrinsic networks. Using resting state functional magnetic resonance imaging (rs-fMRI) this study investigated the association of large-scale cortico-striatal functional connectivity with self-reported and clinician-rated avolition and anhedonia in subjects with schizophrenia. METHODS: Seventeen subjects with schizophrenia (SZ) and 28 healthy controls (HC) underwent rs-fMRI. Using Independent Component Analysis (ICA), we assessed Independent Components (ICs) reflecting intrinsic connectivity networks (ICNs), intra intrinsic functional connectivity within the ICs (intra-iFC), and intrinsic functional connectivity between different ICs (inter-iFC). Avolition and anhedonia were assessed using the Self Evaluation Scale for Negative Symptoms and the Brief Negative Symptom Scale. RESULTS: ICA revealed three striatal components and six cortical ICNs. Both self-rated avolition and anhedonia correlated with increased inter-iFC between the caudate and posterior Default Mode Network (pDMN) and between the caudate and Central Executive Network (CEN). In contrast, clinician-rated avolition and anhedonia were not correlated with cortico-striatal connectivity. Group comparison revealed trend-wise decreased inter-iFC between the caudate and Salience Network (SN) in schizophrenia patients compared to HC. DISCUSSION: Self-rated, but not clinician-rated, avolition and anhedonia was associated with aberrant striatal coupling with the default mode and the central executive network. These findings suggest that self-reported and clinician-rated scores might capture different aspects of motivational and hedonic deficits in schizophrenia and therefore relate to different cortico-striatal functional abnormalities.


Asunto(s)
Esquizofrenia , Anhedonia , Encéfalo , Mapeo Encefálico , Cuerpo Estriado/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética/métodos , Vías Nerviosas/diagnóstico por imagen , Esquizofrenia/diagnóstico por imagen , Autoinforme
20.
JMIR Form Res ; 5(6): e28055, 2021 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-33999835

RESUMEN

BACKGROUND: Since the emergence of COVID-19, health care workers and first responders have been at a high risk for mental health symptoms owing to their exposure to the virus and increased work stress during the pandemic. Although interventions exist to address mental health issues following exposure to disasters, emergencies, and humanitarian crises, considerably less is known about web-based unguided interventions to help mitigate the negative impacts of such events. Additionally, in contexts in which emergencies reduce access to in-person care, remote forms of support are critical, yet there are limited studies on the use of such interventions. Evidence-based, easy-to-use, scalable interventions are direly needed for this population. OBJECTIVE: This study aimed to develop and test the feasibility of an unguided electronic mental health program, COVID-19 Anxiety and Stress Resilience Training (COAST), tailored to first responders and health care personnel, based on scientific evidence and empirically based techniques. METHODS: We developed COVID-19-specific training modules focusing on several domains that are previously reported as key to resilience and stress recovery: self-efficacy, mindfulness, sleep quality, and positive thinking. The program was made available to 702 first responders between May and August 2020, during the COVID-19 pandemic. Sociodemographic, work-, and COVID-19-related information was collected, and psychometric questionnaires were completed. We examined user acceptance and user activity, including module choice and participant feedback. RESULTS: In total, 52 of 702 (7%) first responders to whom we reached out used the program at least once. COAST use was independent of age, sex, or baseline levels of self-efficacy, mindful awareness, sleep quality, and positive thinking (for all, P>.39). First responders who had tested positive and those who had been quarantined were more likely to engage in the program. A click count analysis per module showed that participants used the self-efficacy and mindfulness modules most often, with 382 and 122 clicks, respectively, over 15 weeks. Overall, first responders expressed satisfaction with the program. CONCLUSIONS: Engagement of first responders in the multimodule web-based COAST program was feasible and the first responder cohort expressed overall satisfaction with the program. Those in more difficult circumstances, including those in quarantine and those who tested positive, may be more likely to engage in such programs. Further controlled studies could pave the way for efficacy studies and the development of additional modules, including just-in-time interventions or blended interventions combining individual use of an unguided self-help intervention, such as COAST, with subsequent individual psychotherapy for those who continue to experience stress and psychological symptoms.

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