Giovanni Tani

Diagnosis of midline anomalies of the fetal brain with the three‐dimensional median view

To investigate the effectiveness of a simplified approach to the evaluation of the midline structures of the fetal brain using three‐dimensional (3D) ultrasound.

Pathologic correlates of diffusion MRI changes in Creutzfeldt-Jakob disease

Objective: The cause of hyperintense magnetic resonance changes and reduced apparent diffusion coefficient (ADC) in specific brain regions of patients with Creutzfeldt-Jakob disease (CJD) is unknown. Our aim was to determine the neuropathologic correlates of antemortem water ADC and normalized T2-weighted changes in patients with CJD. Method: Ten patients with CJD and 10 sex- and age-matched healthy controls were studied by DWI and T2-weighted echoplanar MRI. At postmortem, patients with CJD were evaluated for semiquantitative assessment of gliosis and neuronal loss, spongiform changes, and abnormal PrP protein deposition in four cortical regions (occipital, parietal, and temporal cortex, and cingulate gyrus), thalamus, and striatum for a total of 60 regions of interest (ROI). Results: Gliosis and neuronal loss correlated very highly with each other in the 60 ROIs. Where status spongiosus was absent, spongiform change correlated very highly with gliosis and neuronal loss in the cortex, but not in deep gray matter. Spongiform change was also significantly correlated with PrPSc load in both cortical and deep gray ROIs. In deep gray matter, ADC decreased with increasing spongiform change (R2 = 0.78; p < 0.001) and PrPSc load (R2 = 0.51; p = 0.003). In the cortex, ADC decreased with increases in all three, highly correlated, pathologic scores. Conclusion: Antemortem reductions in ADC values, typically found in patients with Creutzfeldt-Jakob disease (CJD), are correlated with spongiform changes seen at autopsy. This could be clearly established in the striatum and thalamus of our patients with CJD where the extent of spongiform change was not significantly correlated with gliosis or neuronal loss.

Role of cerebral ultrasound and magnetic resonance imaging in newborns with congenital cytomegalovirus infection

PURPOSE To assess the diagnostic and prognostic value of cerebral magnetic resonance imaging (cMRI) in comparison with that of cerebral ultrasound (cUS) in predicting neurodevelopmental outcome in newborns with congenital cytomegalovirus (CMV) infection. METHODS Forty CMV-congenitally infected newborns underwent cUS and cMRI within the first month of life. Clinical course, laboratory findings, visual/hearing function and neurodevelopmental outcome were documented. RESULTS Thirty newborns showed normal cMRI, cUS and hearing/visual function in the first month of life; none showed CMV-related abnormalities at follow-up. Six newborns showed pathological cMRI and cUS findings (pseudocystis, ventriculomegaly, calcifications, cerebellar hypoplasia) but cMRI provided additional information (white matter abnormalities in three cases, lissencephaly/polymicrogyria in one and a cyst of the temporal lobe in another one); cerebral calcifications were detected in 3/6 infants by cUS but only in 2/6 by cMRI. Four of these 6 infants showed severe neurodevelopmental impairment and five showed deafness during follow-up. Three newborns had a normal cUS, but cMRI documented white matter abnormalities and in one case also cerebellar hypoplasia; all showed neurodevelopmental impairment and two were deaf at follow-up. One more newborn showed normal cUS and cMRI, but brainstem auditory evoked responses were abnormal; psychomotor development was normal at follow-up. CONCLUSIONS Compared with cUS, cMRI disclosed additional pathological findings in CMV-congenitally infected newborns. cUS is a readily available screening tool useful in the identification of infected newborns with major cerebral involvement. Further studies with a larger sample size are needed to determine the prognostic role of MRI, particularly regarding isolated white matter lesions.

A combined a-EEG and MR spectroscopy study in term newborns with hypoxic–ischemic encephalopathy

OBJECTIVES Brain damage following a perinatal hypoxic-ischemic (HI) insult has been documented by different diagnostic techniques. The aim of the present study was to relate a-EEG time course during the first 24h of life to brain metabolic changes detected by proton MR spectroscopy ((1)H-MRS) at 7-10days of life and to evaluate their correlation with outcome. METHODS Thirty-two patients with any grade HI encephalopathy were studied. Thirty-one out of 32 patients survived and underwent (1)H-MRS examination at 7-10days of life; a-EEG was recorded during the first 24h of life in 27/32 newborns; 26 patients underwent both examinations. Griffiths test, evaluation of motor skills, visual and hearing function were performed at regular intervals until the age of 2years. RESULTS a-EEG at 6, 12 and 24h of life showed a significant correlation with outcome. N-acetyl-aspartate/creatine (Cr), Lactate/Cr and myo-inositol differed significantly between patients with normal or poor outcome. a-EEG time course during the first 24h of life showed improvement in newborns with normal (1)H-MRS and good outcome and a deterioration in those with abnormal (1)H-MRS and poor outcome. CONCLUSIONS a-EEG time course may be able to document the severity and the evolution of the cerebral damage following an HI event. a-EEG is related to the severity of cerebral injury as defined by (1)H-MRS and both examinations showed a good correlation with outcome. These data, obtained in non-cooled infants, may represent reference data for future investigations in cooled infants.

Computed Tomography and Magnetic Resonance Imaging Findings in Ophthalmoplegic Migraine

A patient with ophthalmoplegic migraine is described, and his computed tomography and magnetic resonance imaging findings are discussed. According to our results, triad migraine, third nerve palsy, and focal enhancement of an enlarged third cranial nerve at the root exit zone should be considered pathognomonic of the disease, and further examinations should be avoided. Pathogenetic theories of the disease are discussed, and we suggest a new pathogenetic theory.

Laser Ablation of Metals: A 3D Process Simulation for Industrial Applications

A model for laser milling simulation is presented in this paper. A numerical model able to predict the physical phenomena involved in laser ablation of metals was developed where the heat distribution in the work piece, the prediction of the velocity of the vapor/liquid front, and the physical state of the plasma plume were taken into account. The model is fully 3D and the simulations makes it possible to predict the ablated workpiece volume and the shape of the resulting craters for a single laser pulse or multiple pulses, or for any path of the laser spot. The numerical model was implemented in C+ + and an overview of the code capacities is presented.

Dynamic Hybrid Modeling of the Vertical Z Axis in a High-Speed Machining Center: Towards Virtual Machining

This paper describes the modeling and simulation of the Z axis of a five axis machining center for high-speed milling. The axis consists of a mechanical structure: machine head and electro-mandrel, a CNC system interfaced with the feed drive, and a pneumatic system to compensate for the weight of the vertical machine head. These subsystems were studied and modeled by means of: (I) finite element method modeling of the mechanical structure; (2) a concentrated parameter model of the kinematics of the axis; (3) a set of algebraic and logical relations to represent the loop CNC-Z feed drive; (4) an equation set to represent the functioning of the pneumatic system; and (5) a specific analytical model of the friction phenomena occurring between sliding and rotating mechanical components. These modeled subsystems were integrated to represent the dynamic behavior of the entire Z axis. The model was translated in a computer simulation package and the validation of the model was made possible by comparing the outputs of simulation runs with the records of experimental tests on the machining center. The firm which promoted and financed the research now has a virtual tool to design improved machine-tool versions with respect to present models, designed by traditional tools.

MR findings in Seckel's syndrome: report of a case

Abstract The cranial MR findings in a patient with Seckels syndrome are presented. The examination demonstrated osseous anomalies of the face, but, unlike previous reports, the brain and cerebellum were normal. The authors emphasise the importance of further reports on MR findings in patients affected by Seckels syndrome.

A common case of gastroenteritis in a child followed by an axial torsion of Meckel diverticulum: a rare and unusual complication

A 1-year-old boy presented at our hospital with common gastroenteritis symptoms such as fever, vomiting and diarrhoea. Clinical and laboratory findings were normal. An emergency ultrasound examination was performed and excluded abdominal complications. After 2 days of complete regression of symptoms, the patient began to vomit again, diarrhoea stopped with a sudden worsening of clinical conditions. Laboratory and radiological findings showed signs of an acute abdomen with differential diagnosis between an infectious and an obstructive cause. Owing to the rapid and progressive toxic condition, an emergency laparoscopy was performed. An axial torsion of a swollen and gangrenous Meckels diverticulum was detected.

A New Computationally Efficient Model for Tempering in Multitrack Laser Hardening in Medium Carbon Steels

The bottleneck in laser hardening principally occurs when large surfaces have to be treated because this process situation leads to multitrack laser scanning in order to treat all the component surfaces. Unfortunately, multitrack laser trajectories generate an unwanted tempering effect that depends on the overlapping of two close trajectories. To reduce the softening effects, a simulator capable to optimize the process parameters, such as laser power and speed and number and types of trajectories, could sensibly increase the applicability of the process. In this paper, an original model for the tempering is presented. By introducing a tempering time factor for the martensitic transformation, the hardiness reduction can be predicted according to any laser process parameters, material, and geometry. Experimental comparisons will be presented to prove the accuracy of the model.