Roberto Cerini

Investigation of corpus callosum in schizophrenia with diffusion imaging

BACKGROUND Corpus callosum (CC) is the main white matter commissure between the two cerebral hemispheres. Abnormalities of CC have been shown in schizophrenia patients by magnetic resonance imaging (MRI) studies. We here further investigated CC organization with diffusion imaging (DWI) in a sample of schizophrenia patients recruited from the epidemiologically defined catchment area of South Verona, Italy. METHODS Sixty-seven patients with schizophrenia and 70 normal controls were studied. Regions of interests (ROIs), standardized at 5 pixels, were placed in CC on the non-diffusion weighted echoplanar images (b = 0) and were then automatically transferred to the corresponding maps to obtain the apparent diffusion coefficient (ADC) of water molecules. RESULTS ADC measures for all callosal subregions in schizophrenia patients were significantly greater compared to normal controls (ANCOVA, p < 0.05). Positive symptoms significantly correlated with anterior callosal ADC measures (partial correlation analyses, p < 0.05). CONCLUSIONS These findings support the existence of widespread microstructure disruption of CC in schizophrenia, which may ultimately lead to inter-hemispheric misconnection, and also suggest a specific role of anterior transcallosal disconnectivity in underlying positive symptoms. Future longitudinal MRI studies in high risk and first-episode patients together with neurophysiological tests are indicated to further examine CC anatomical abnormalities and inter-hemispheric transmission in schizophrenia.

EEG and fMRI Coregistration to Investigate the Cortical Oscillatory Activities During Finger Movement

Electroencephalography combined with functional magnetic resonance imaging (EEG-fMRI) may be used to identify blood oxygenation level dependent (BOLD) signal changes associated with physiological and pathological EEG event. In this study we used EEG-fMRI to determine the possible correlation between topographical movement-related EEG changes in brain oscillatory activity recorded from EEG electrodes over the scalp and fMRI-BOLD cortical responses in motor areas during finger movement. Thirty-two channels of EEG were recorded in 9 subjects during eyes-open condition inside a 1.5 T magnetic resonance (MR) scanner using a MR-compatible EEG recording system. Off-line MRI artifact subtraction software was applied to obtain continuous EEG data during␣fMRI acquisition. For EEG data analysis we used the event-related-synchronization/desynchronization (ERS/ERD) approach to investigate where movement-related decreases in alpha and beta power are located. For image statistical analysis we used a general linear model (GLM) approach. There was a significant correlation between the positive-negative ratio of BOLD signal peaks and ERD values in the electrodes over the region of activation. We conclude that combined EEG-fMRI may be used to investigate movement-related oscillations of the human brain inside an MRI scanner and the movement-related changes in the EMG or EEG signals are useful to identify the brain activation sources responsible for BOLD-signal changes.

Two novel mutations in dynamin-2 cause axonal Charcot-Marie-Tooth disease.

Background: Recently, mutations affecting different domains of dynamin-2 (DNM2) were associated alternatively with autosomal dominant centronuclear myopathy or dominant intermediate (demyelinating and axonal) Charcot–Marie–Tooth disease (CMT) type B. Objective: To assess the etiologic role of DNM2 in CMT. Methods: We performed a mutational screening of DNM2 exons 13 through 16 encoding the pleckstrin homology domain in a large series of CMT patients with a broad range of nerve conduction velocities and without mutations in more common genes. Results: We identified two novel DNM2 mutations that cosegregated with purely axonal CMT in two pedigrees without clinical evidence of primary myopathy. Conclusion: Patients with axonal Charcot–Marie–Tooth disease type 2 neuropathy without mutations in more common genes should undergo investigation for DNM2 pleckstrin homology.

Decreased entorhinal cortex volumes in schizophrenia

BACKGROUND The entorhinal cortex is located in the medial temporal lobe and is involved in memory and learning. Previous MRI studies reported conflicting findings in schizophrenia, showing normal or reduced entorhinal size. OBJECTIVES To explore entorhinal cortex volumes in a large sample of patients with schizophrenia recruited from the geographically defined catchment area of South Verona (i.e. 100,000 inhabitants). We also investigated the size of hippocampus as part of the medial temporal lobe. METHODS 70 patients with schizophrenia and 77 normal controls underwent a session of MRI (TR=2060 ms, TE=3.9 ms, slice thickness=1.25 mm). Entorhinal and hippocampal volumes were explored using the Brains2 software. RESULTS A significant group effect was found for total entorhinal cortex but not for hippocampus, with patients suffering from schizophrenia having smaller entorhinal volumes compared to normal subjects (F=6.24, p=0.01), particularly on the right side (F=9.76, p=0.002). Also, the laterality index for entorhinal cortex was higher in normal individuals than in patients with schizophrenia (F=5.45, p=0.02). CONCLUSIONS Consistent with some of the previous reports, our study confirmed the presence of abnormally decreased entorhinal volumes, particularly on the right side, in a large number of patients with schizophrenia and also found altered asymmetry. This may play a major role in the psychopathology and cognitive disturbances of the disease. Future longitudinal MRI studies including high-risk subjects and drug-free, first-episode patients are crucial to further understand whether entorhinal cortex shrinkage is already present at the onset of the illness or appears as a consequence of the illness.

Brain oscillatory activity during motor imagery in EEG-fMRI coregistration

The purpose of the present work was to investigate the correlation between topographical changes in brain oscillatory activity and the blood oxygenation level-dependent (BOLD) signal during a motor imagery (MI) task using electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) coregistration. EEG was recorded in 7 healthy subjects inside a 1.5 T MR scanner during the imagination of the kinesthetic experience of movement. A Fast Fourier Transform was applied to EEG signal in the rest and active conditions. We used the event-related-synchronization (ERS)/desynchronization (ERD) approach to characterize where the imagination of movement produces a decrease in alpha and beta power. The mean alpha map showed ERD decrease localized over the contralateral sensory motor area (SM1c) and a light desynchronization in the ipsilateral sensory motor area (SM1i); whereas the mean beta map showed ERD decrease over the supplementary motor area (SMA). fMRI showed significant activation in SMA, SM1c, SM1i. The correlation is negative in the contralateral side and positive in the ipsilateral side. Using combined EEG-fMRI signals we obtained useful new information on the description of the changes in oscillatory activity in alpha and beta bands during MI and on the investigation of the sites of BOLD activity as possible sources in generating these rhythms. By correlating BOLD and ERD/ERS we may identify more accurately which regions contribute to changes of the electrical response.

Radiation dose saving through the use of cone-beam CT in hearing-impaired patients

PurposeBionic ear implants provide a solution for deafness. Patients treated with these hearing devices are often children who require close follow-up with frequent functional and radiological examinations; in particular, multislice computed tomography (MSCT). Dental volumetric cone-beam CT (CBCT) has been reported as a reliable technique for acquiring images of the temporal bone while delivering low radiation doses and containing costs. The aim of this study was to assess, in terms of radiation dose and image quality, the possibility of using CBCT as an alternative to MSCT in patients with bionic ear implants.Materials and methodsOne hundred patients (mean age 26 years, range 7–43) with Vibrant SoundBridge implants on the round window underwent follow-up: 85 with CBCT and 15 with MSCT. We measured the average tissue-absorbed doses during both MSCT and CBCT scans. Each scan was focused on the temporal bone with the smallest field of view and a low-dose protocol. In order to estimate image quality, we obtained data about slice thickness, high- and low-contrast resolution, uniformity and noise by using an AAPM CT performance phantom.ResultsAlthough the CBCT images were qualitatively inferior to those of MSCT, they were sufficiently diagnostic to allow evaluation of the position of the implants. The effective dose of MSCT was almost three times higher than that of CBCT.ConclusionsOwing to low radiation dose and sufficient image quality, CBCT could be considered an adequate technique for postoperative imaging and follow-up of patients with bionic ear implants.RiassuntoObiettivoGli impianti bionici all’orecchio rappresentano una soluzione contro la sordità. I pazienti trattati con questi tipi di ausili, spesso bambini, necessitano di un follow-up di esami sia funzionali che radiologici, in particolare mediante tomografia computerizzata multistrato (MSTC). La TC volumetrica dentale a fascio conico (CBCT) è una metodica utile allo studio dell’osso temporale, con il vantaggio di erogare basse dosi di radiazioni ionizzanti e di avere costi di gestione contenuti. Lo scopo dello studio è di valutare la CBCT in termini di dose radiante e di qualità d’immagine: il suo eventuale impiego in alternativa alla MSTC (con il protocollo attualmente utilizzato) comporterebbe infatti una sostanziale riduzione della dose ai pazienti con orecchio bionico.Materiali e metodiSono stati inclusi 100 pazienti ipoacusici (età media 26 anni, range 7–43), trattati mediante protesi Vibrant SoundBridge alla finestra rotonda, 15 studiati in follow-up mediante TC e 85 mediante CBCT, calcolando le dosi medie assorbite per tessuto sia durante esame MSTC che CBCT: ogni studio era focalizzato sull’osso temporale utilizzando il più piccolo campo di vista ed il protocollo a bassa dose radiante. Per la stima della qualità dell’immagine, sono stati ottenuti i valori di spessore di strato, risoluzione ad alto e basso contrasto e uniformità/rumore mediante l’uso di fantoccio AAPM CT performance.RisultatiLe immagini ottenute con la CBCT sono di qualità inferiore rispetto alla MSTC, ma sufficientemente diagnostiche, permettendo di valutare con sicurezza la posizione delle estremità degli impianti acustici. La dose efficace della MSTC è risultata circa tre volte superiore rispetto a quella della CBCT.ConclusioniLa CBCT, grazie alla bassa dose impartita e alla sufficiente qualità delle immagini, può essere considerata tecnica radiologica adeguata per i controlli postoperatori ed il follow-up dei pazienti con orecchio bionico.

Dysmorphic features, simplified gyral pattern and 7q11.23 duplication reciprocal to the Williams-Beuren deletion.

We report a patient with mild pachygyria, ascertained during a screening of subjects with abnormal neuronal migration and/or epilepsy, having a 7q11.23 duplication reciprocal to the Williams-Beuren critical region (WBCR) deletion. He exhibited speech delay and mental retardation together to type II trigonocephaly and other abnormalities. The probands mother carried the same imbalance, though her phenotype was milder and no abnormal conformation of the cranium was reported. She had suffered a few seizures in infancy, as already described in other duplicated subjects. This genomic imbalance, now described in 17 subjects, including one parent for each of the four probands, is associated with a variable phenotype. Speech impairment is present in most cases; no distinctive facial gestalt is recognizable; seizures have been reported in four subjects and brain magnetic resonance, performed in eight cases, resulted abnormal in six, while detected abnormal neuronal migration in two. Although the clinical description of additional cases is needed to delineate a definite phenotypic core for WBCR duplications, trigonocephaly, also reported in another dup(7)(q11.23) patient, is possibly a trait that, together with speech impairment, may call for clinically oriented specific screening. Abnormal development of the cerebral cortex, reported also in the Williams-Beuren deletion, suggests that at least one gene is present in the critical region whose deletion/duplication impairs neuronal migration.

Thalamic-insular dysconnectivity in schizophrenia: Evidence from structural equation modeling

Structural and functional studies have shown that schizophrenia is often associated with frontolimbic abnormalities in the prefrontal and mediotemporal regions. It is still unclear, however, if such dysfunctional interaction extends as well to relay regions such as the thalamus and the anterior insula. Here, we measured gray matter volumes of five right‐hemisphere regions in 68 patients with schizophrenia and 77 matched healthy subjects. The regions were amygdala, thalamus, and entorhinal cortex (identified as anomalous by prior studies on the same population) and dorsolateral prefrontal cortex and anterior insula (isolated by voxel‐based morphometry analysis). We used structural equation modeling and found altered path coefficients connecting the thalamus to the anterior insula, the amygdala to the DLPFC, and the entorhinal cortex to the DLPFC. In particular, patients exhibited a stronger thalamus‐insular connection than healthy controls. Instead, controls showed positive entorhinal‐DLPFC and negative amygdalar‐DLPFC connections, both of which were absent in the clinical population. Our data provide evidence that schizophrenia is characterized by an impaired right‐hemisphere network, in which intrahemispheric communication involving relay structures may play a major role in sustaining the pathophysiology of the disease. Hum Brain Mapp, 2012.

Schizophrenia severity, social functioning and hippocampal neuroanatomy: three-dimensional mapping study

BACKGROUND Hippocampal shrinkage is commonly reported in schizophrenia, but its role in the illness is still poorly understood. In particular, it is unclear how clinical and psychosocial variables relate to hippocampal volumes. AIMS To investigate neuroanatomic differences in the hippocampus using three-dimensional (3D) computational image analysis. METHOD We used high-resolution magnetic resonance imaging and surface-based modelling to map the 3D profile of hippocampal differences in adults with schizophrenia (n = 67) and a healthy control group (n = 72). Manual tracings were used to create 3D parametric mesh models of the hippocampus. Regression models were used to relate diagnostic measures to maps of radial distance, and colour-coded maps were generated to show the profile of associations. RESULTS There was no detectable difference between the schizophrenia and control groups in hippocampal radial distance. In the schizophrenia group, however, bilateral shape deflation was associated with greater illness severity (length of illness, positive and negative symptoms) and with poorer social functioning (educational level, quality of life and health status), which survived Bonferroni correction. CONCLUSIONS Illness severity and poor social functioning may be associated with hippocampal deflation in schizophrenia. As a structural sign of poor outcome, imaging measures might help to identify a subgroup of patients who may need specific treatment to resist hippocampal shrinkage, such as cognitive rehabilitation or physical exercise.

Imaging in 28 children with cochlear nerve aplasia

Conclusion. Preoperative CT and MRI assessment of children with severe or profound sensorineural hearing loss (SNHL) is critical for determining implant candidacy. Objectives. There are a significant number of children who do not show any auditory development with a cochlear implant (CI), possibly due to cochlear nerve (CN) aplasia/hypoplasia. Regardless of the suspected etiology, if a CI is not providing auditory development the clinician should carefully evaluate the possibility of a CN malformation and re-evaluate the child with detailed neuroimaging studies. If the imaging evaluation shows severe cochlear malformation or CN aplasia there is some developmental urgency to consider auditory brainstem implant (ABI) surgery. Subjects and methods. Twenty-eight children affected by congenital SNHL were examined by CT and MRI. Evaluation of the cerebellopontine angle (CPA), internal auditory canal (IAC), cranial nerves, and membranous labyrinth was performed. Six children had been previously fitted elsewhere with a CI with no sound detection. Results. Suspected congenital anomalies were confirmed by CT and MRI in all 28 children: 16 with associated labyrinthine malformations; 1 with outer, middle, and inner ear malformations; and 2 with associated monolateral facial nerve aplasia.