Prognostic MRI parameters in acute traumatic cervical spinal cord injury.

PURPOSE: The aim of this study is to estimate the prognostic value of some features documented on preoperative MRI study in patients with acute cervical spinal cord injury. METHODS: The study was conducted in patients operated for cervical spinal cord injury (cSCI) from April 2014 to October 2020. The quantitative analysis on preoperative MRI scans included: length of the spinal cord intramedullary lesion (IMLL the canal diameter at the level of maximal spinal cord compression (MSCC) and the presence of intramedullary hemorrhage. The canal diameter at the MSCC was measured on the middle sagittal FSE-T2W images at the maximum level of injury. The America Spinal Injury Association (ASIA) motor score was used for neurological assessment at hospital admission. At 12-month follow-up all patients were examined with the SCIM questionnaire. RESULTS: At linear regression analysis, the length of the spinal cord lesion [ß coefficient -10.35, 95% confidence interval (CI)-13.71 to-6.99; p < 0.001], the diameter of the canal at the level of the MSCC (ß coefficient 6.99, 95% CI 0.65 to 13.33; p = 0.032), and the intramedullary hemorrhage (ß coefficient - 20.76, 95% CI - 38.70 to - 2.82; p = 0.025), were significantly associated with the score at the SCIM questionnaire at one year follow-up: shorter spinal cord lesion, greater diameter of the canal at the level of the MSCC, and absence of intramedullary hemorrhage were predictors of better outcome. CONCLUSION: According to the findings of our study, the spinal length lesion, canal diameter at the level of spinal cord compression and intramedullary hematoma documented by the preoperative MRI study were associated with the prognosis of patients with cSCI.

Imitation Strategies in Callosotomized Patients.

Imitation is a human ability rooted in early life. It allows people to interact with each other by observing and reproducing simple and complex movements alike. Imitation can occur in at least two forms: the rst, de ned as anatomical, seems to be based primarily on the mental construct of the "body schema" because the imitating movement corresponds precisely to the imitated movement in bodily terms, but not in terms of spatial compatibility. For example, a right arm movement of a model is imitated with a right arm movement by a facing imitator in a spatially incompatible fashion. The other form, de ned as specular or mirror-mode, involves a spatially compatible matching between imitated and imitating movements, as when an imitator moves her right arm upon viewing a corresponding left arm movement of a facing model (Chiavarino et al., 2007). In a previous study, healthy subjects showed a slight (61%) preference for the specular mode when freely imitating meaningful and meaningless gestures, whereas they strongly preferred the anatomical mode (93%) when given an intentionally ambiguous instruction such as "use the same (or the opposite) limb as the model" (Pierpaoli et al., 2014). In the present investigation it has been shown that callosotomized patients tended to favour the mirror-mode in both the free (66%) and the instructed condition (61% responses in driven sessions) regardless instructions given by the experimenter. Moreover, present data suggest that the extent of the callosotomy may in uence the patient's performance.

Further evidence for the topography and connectivity of the corpus callosum: an FMRI study of patients with partial callosal resection.

BACKGROUND AND PURPOSE: This functional MRI study was designed to describe activated fiber topography and trajectories in the corpus callosum (CC) of six patients carrying different degree of partial callosal resection. METHODS: Patients receiving gustatory, tactile, and visual stimulation according to a block-design protocol were scanned in a 1.5 Tesla magnet. Diffusion tensor imaging (DTI) data were also acquired to visualize spared interhemispheric fibers. RESULTS: Taste stimuli evoked bilateral activation of the primary gustatory area in all patients and foci in the anterior CC, when spared. Tactile stimuli to the hand evoked bilateral foci in the primary somatosensory area in patients with an intact posterior callosal body and only contralateral in the other patients. Callosal foci occurred in the CC body, if spared. In patients with an intact splenium central visual stimulation induced bilateral activation of the primary visual area as well as foci in the splenium itself. CONCLUSION: Present data show that interhemispheric fibers linking sensory areas crossed through the CC at the sites where the different sensory stimuli evoked activation foci, and that topography of callosal foci evoked by sensory stimulation in spared CC portions is consistent with that previously observed in subjects with intact CC.

Closed Meningo(encephalo)cele: a new feature in Hunter syndrome.

BACKGROUND AND PURPOSE: Hunter syndrome (MPS type II) is a rare X-linked recessive disease caused by lysosomal enzyme iduronate-2-sulfatase deficiency, characterized by frequent and variable brain and skull involvement. Our objective was determine the frequency of closed cephaloceles in a large cohort of subjects affected with Hunter syndrome and to investigate possible correlations with clinical and neuroradiologic findings. MATERIALS AND METHODS: Brain MR imaging of 33 patients (32 males and 1 female, age range 2.5-30.8 years, mean age 10.4 years) affected with Hunter syndrome were retrospectively evaluated. Eleven (age range 3.6-30.8 years; mean age 15.1) presented with an "attenuated" phenotype, while 22 (age range 2.5-19.1 years; mean age 8.2) had a "severe" phenotype. RESULTS: A closed cephalocele was detected in 9/33 patients (27%) at the level of anterior and middle fossa in 6 and 3 cases, respectively; 6/9 subjects were affected with the attenuated phenotype and 1/9 suffered from epilepsy. Closed cephaloceles did not show a significant association with other brain and spine MR imaging features of Hunter disease, such as enlargement of perivascular spaces, cisterna magna, pituitary sella, ventricles and subarachnoid spaces, craniosynostosis, dens hypoplasia, white matter abnormalities, spinal stenosis due to periodontoid cap, platyspondylia, or intervertebral disk anomalies. CONCLUSIONS: Closed cephaloceles are frequent in Hunter syndrome and should be considered a neuroradiologic feature of this disease.

Diffusion tensor tracking of callosal fibers several years after callosotomy.

Diffusion tensor imaging (DTI) can provide more detailed in vivo information on the structural preservation of transected white matter tracts than conventional imaging methods. Here we show for the first time tracks of severed callosal fibers up to 17 years from resection. Five patients subjected to complete or partial callosotomy several years before the study were examined with DTI and compared to a normal control. Transected fibers were traced in all patients and were more clearly visible in the anterior and posterior parts than in the middle of the commissure. These findings suggest that microstructural changes persist for many years in the severed fibers, as also reflected by fractional anisotropy and apparent diffusion coefficient values, enabling a reconstruction of the longitudinal organization of severed central tracts that could not be achieved with previous techniques.

Atypical Clinical Picture in a Patient with Benign Occipital Epilepsy: Diagnostic Contribution of Morpho-Functional MR. A Case Report.

Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) is a maternally inherited disease due to mitochondrial DNA (mtDNA) point mutations. The clinical phenotype varies in relation to the systems affected, age at onset and disease severity. The characteristic signs of MELAS are nausea and vomiting due to acidosis, headache, epilepsy, ataxia or generalized weakness, ophthalmoplegia, motor and sensory focal neurological deficits. The clinical course may improve due to partial regression of the typical lesions, but the prognosis is usually adverse. A 19-year-old man with a diagnosis of benign occipital epilepsy and resumption of seizure activity with focal occipital attacks since the age of 14 years came to our attention for the recent onset of drug-resistant electroclinical seizures of long duration with complex symptoms, where the dominant clinical feature was an intense, persistent bilateral periorbital migraine with nausea and vomiting, scintillation scotomata and blurring of vision. MR studies were performed at our institution in the immediate post-seizure phase and then at one week, three and six months. The acute-phase morphological scans showed a right cortical-subcortical area with altered signal in the occipitopolar region that was hypointense on T1 and hyperintense on T2 and FLAIR, with cortical thickening and effacement of the sulci. Contrast-enhanced scans did not demonstrate BBB alterations. The DWI scans showed a right temporo-occipital cortical area with higher signal intensity. In the subsequent examinations the area with altered signal shrank gradually and significantly in parallel with improvement in clinical conditions. The diagnostic hypothesis of benign occipital epilepsy was consistent neither with the clinical course, characterized by persistent headache, visual disturbance and refractoriness to antiepileptic drugs, nor with the temporal-occipital cortical MR findings, which resembled ischemic lesions but displayed a non-territorial pattern as well as reversibility over time. These elements guided in the diagnosis of MELAS, which was subsequently confirmed by identification of the typical gene mutation. On DWI the stroke-like lesions of MELAS are seen more frequently as focal hyperintense areas compared with healthy parenchyma. Such high signal intensity likely corresponds to T2 shine-through rather than cytotoxic edema. Indeed, several studies have demonstrated that in acute-phase scans of MELAS stroke-like lesions DWI hyperintensity is associated with increased ADC values that are not associated with restricted water diffusivity, reflecting the metabolic rather than anoxic-ischemic nature of these changes. In the present case, morphological MR associated with DWI was very helpful in guiding the diagnosis by demonstrating some pathognomonic features of MELAS stroke-like lesions such as cortical-subcortical involvement of the posterior hemispheres, the non-territorial pattern, lesion reversibility and the pathophysiological role of vasogenic edema in inducing an increase in extracellular water and thus in diffusion values.

Leigh Syndrome: an MR Study of Three Cases.

Leigh syndrome (LS), or subacute necrotizing encephalomyelopathy, is the most common childhood mitochondrial encephalopathy, accounting for more than 50% of cases in this age group. Its estimated incidence is 1:40,000 - 1:77,000 liveborn infants a year. LS is a rare progressive multisystem fatal disorder inherited by autosomal recessive, X-linked and maternal transmission. Clinical onset is predominantly in the first two years of life (average: six months); 50% of patients die within a year, even though there are later- and even adult-onset forms with a more protracted evolution. LS is due to a deficit of various respiratory chain and Krebs cycle enzymes resulting in insufficient production of adenosine triphosphate (ATP), in particular cytochrome-c-oxidase (COX), pyruvate carboxylase, pyruvate dehydrogenase complex and complex I of the respiratory chain, which share an autosomal recessive and X-linked mode of transmission. Cases with maternal inheritance (MILS) are due to a mitochondrial DNA (mtDNA) point mutation. LS is clinically heterogeneous in relation to the severity of the metabolic dysfunction and is characterized by muscle involvement and especially CNS disorders, particularly psychomotor retardation, ocular symptoms, hypotonia and pyramidal signs. Death is most commonly due to respiratory failure, status epilepticus and sudden coma. The major neuropathological findings, first described by Leigh in 1951, are symmetrical foci of spongy necrosis associated with vessel proliferation and reactive gliosis in basal nuclei, brainstem and thalamus grey matter. The neuronal metabolic alteration can also affect the white matter, resulting in delayed myelination or hypomyelination. The diagnosis rests on clinical signs, elevated CSF lactate, pyruvate and alanine, and biochemical and neuroradiological data. We describe two patients with LS studied with morphological MR associated with diffusion and spectroscopy techniques to assess the diagnostic potential of standard MR imaging and establish whether the association of functional MR methods can improve its diagnostic accuracy. A case of LS with a post-mortem MR study is also described. Three patients with a diagnosis of LS based on clinical, CSF and laboratory data were studied on a GE SIGNA EXCITE 1.5 T unit using an eight-channel phased-array head coil to acquire standard sequences (SE T1; TSE DP T2; FLAIR) and echo-planar diffusion-weighted sequences (DWI; b= 1000 s/mm2) with calculation of ADC maps. The spectroscopic study used single-voxel (TE/TR ms = 144/1500) and multi-voxel techniques (TE/TR ms = 144/1000) at the level of the basal nuclei. Bilateral and symmetrical involvement of basal nuclei grey matter with T2 hyperintensity was a consistent finding in the morphological MR study. In one patient, associated white matter involvement with T2 hyperintensity in periventricular and retrotrigonal areas reflected delayed myelination or hypomyelination. The deep grey matter changes, sometimes associated with white matter lesions, suggested a diagnosis of subacute necrotizing encephalomyelopathy, in line with the literature. Acute-phase ADC values in affected areas were lower than those of normal grey and white matter and displayed signal hyperintensity on DWI. Reduced ADC values are associated with restricted water diffusivity typical of cytotoxic edema. Spectroscopy showed a high lactate peak, reflecting altered anaerobic glycolysis, and a reduced NAA peak in affected areas, which are however non-specific findings. The most informative study in these patients is standard MR associated with functional techniques, which can confirm the diagnosis obtained with morphological imaging.

Contribution of the corpus callosum to bilateral representation of the trunk midline in the human brain: an fMRI study of callosotomized patients.

Human brain studies have shown that the cutaneous receptors of trunk regions close to the midline are represented in the first somatosensory cortex (SI) of both hemispheres. The present study aims to establish whether in humans, as in non-human primates, the bilateral representation of the trunk midline in area SI depends on the corpus callosum. Data were obtained from eight callosotomized patients: three with complete callosal resection, one with a partial posterior resection including the splenium and the callosal trunk, and four with partial anterior resections sparing the splenium and in one case also the posterior part of the callosal trunk. The investigation was carried out with functional magnetic resonance imaging. Unilateral tactile stimulation was applied by rubbing ventral trunk regions close to the midline (about 20 x 10 cm in width) with a soft cotton pad (frequency 1 Hz). Cortical activation foci elicited by unilateral stimulation of cutaneous regions adjacent to the midline were detected in the contralateral post-central gyrus (PCG), in a region corresponding to the trunk ventral midline representation zone of area SI, as described in a previous study of intact subjects. In most patients, activation foci were also found in the ipsilateral PCG, again as in subjects with an intact corpus callosum. The data confirm that the skin regions adjacent to the trunk midline are represented bilaterally in SI, and indicate that ipsilateral activation is at least partially independent of the corpus callosum.

Effects of ionic and non-ionic paramagnetic contrast media on brain bio-electric activity.

The potential neurotoxic effects of gadolinium (Gd)-based compounds for enhanced MRI are not completely understood. We investigated electroencephalography changes induced by ionic and non-ionic Gd-based compounds administered intravenously in patients affected by lesions of the central nervous system (CNS) characterized by breakdown of the blood-brain barrier. This double-blind, randomized, study of two parallel groups involved 40 patients scheduled for an MRI examination with contrast medium for known CNS lesions. Twenty patients were randomly allocated to receive non-ionic Gd-DTPA-BMA/gadodiamide and 20 patients were randomly allocated to receive ionic Gd-DTPA/gadopentetate. For both groups the intravenous dose was 0.1 mmol/kg body weight. Three electroencephalography recordings were performed: immediately before, during, and 15 min after contrast medium injection. Mean and peak frequencies of the beta band and absolute power of the delta and/or theta bands of the electroencephalograms (EEGs) were noted. Each EEG was also evaluated to detect any alterations. The values of the 8-12 Hz band showed a significant increase during and after injection versus baseline in the gadopentetate group (P<0.05) and a significant decrease during injection in the gadodiamide group (P<0.05). The values of the 12-16 Hz band showed a significant increase versus baseline during and after injection in the gadopentetate group (P<0.05). The electrophysiological method based on computerised spectral analysis is a sensitive tool for evaluating effects of contrast media on brain bio-electric activity. EEG changes are detectable, even in the absence of any clinical evidence. It would appear that there might be clinical advantages in the use of non-ionic compounds.

Is haemosiderin visible indefinitely on gradient-echo MRI following traumatic intracerebral haemorrhage?

Gradient-echo (GE) MRI has been demonstrated to be the most sensitive current technique for detection of intracerebral haemosiderin, especially in the chronic stage of haemorrhage. Our purpose was to see whether GE MRI shows old haemorrhage indefinitely. We reviewed serial GE images of 105 adults with imaging features consistent with post-traumatic intracerebral haemorrhage, who had serial MRI at 1, 4-6, 12, and 24 months after trauma. Of 1235 scattered low-signal foci consistent with isolated intracerebral haemosiderin deposits on images at 4-6 months, 248 (20.1%) were not seen at 24-month assessment. Reviewing individual patients, we saw that in 71.8% of those with scattered haemosiderin deposits and 46.4% of those with haemosiderin surrounded by gliosis, the low-signal foci appeared less conspicuous with time. Even given certain limitations to the interpretation of these findings, it would appear that, even with the use of GE MRI, time affects the visibility of haemorrhagic intracerebral lesions. We therefore conclude that a time of 4-6 months to 1 year or slightly more should be recommended for most precise detection of haemosiderin deposits on MRI of head-injured patients, should this be thought desirable. Normal GE images may not exclude old haemorrhage.

Joubert syndrome with associated corpus callosum agenesis.

In 1969, Joubert et al. studied a family where four of six children had a severe clinical condition with episodic alternate hyperpnoea and apnoea, hypotonia, ataxia, psychomotor delay, and abnormal ocular movements. Two of the four had agenesis of the posterior-inferior part of the cerebellar vermis and two had complete agenesis of the vermis. We report a 5-month-old girl with Joubert syndrome in whom MRI shows both features typical of this condition and associated corpus callosum agenesis. To our knowledge, complete callosal agenesis has been infrequently reported in children with Joubert syndrome; consequently, it might be regarded as a casual finding. Nevertheless, the hypothesis of a developmental abnormality of midline structures extended to the supratentorial compartment is rather attractive.

Mechanical noxious stimuli cause bilateral activation of parietal operculum in callosotomized subjects.

The patterns of cortical activation evoked by tactile and mechanical painful stimulation in six normal subjects and three patients with complete resection of the corpus callosum are described and compared, with emphasis on the parietal operculum. Stimulus-related cortical activation was investigated by functional magnetic resonance imaging. In both groups, painful stimulation activated the first somatosensory, insular and cingulate cortices in the contralateral hemisphere, and the parietal opercular cortex in both hemispheres. Comparison between the two patterns of cortical activation demonstrated that ipsilateral activation by unilateral painful stimulation is at least partially independent of the corpus callosum and suggests a different organization of the pain and touch systems.

An unusual spinal presentation of Whipple disease.

SUMMARY: When Whipple disease (WD) is confined to the CNS, diagnosis may be difficult. We report a case of WD with spinal presentation in an otherwise healthy woman who had a 5-year history of relapsing-remitting cervico-thoracic myelopathy. We suggest that the diagnosis of WD should be considered in the presence of an enlarged and enhancing spinal cord even in the absence of any systemic involvement.

Posterior corpus callosum and interhemispheric transfer of somatosensory information: an fMRI and neuropsychological study of a partially callosotomized patient.

Interhemispheric somatosensory transfer was studied by functional magnetic resonance imaging (fMRI) and neuropsychological tests in a patient who underwent resection of the corpus callosum (CC) for drug-resistant epilepsy in two stages. The first resection involved the anterior half of the body of CC and the second, its posterior half and the splenium. For the fMRI study, the hand was stimulated with a rough sponge. The neuropsychological tests included: Tactile Naming Test (TNT), Same-Different Recognition Test (SDRT), and Tactile Finger Localization Test (intra- and intermanual tasks, TFLT). The patient was studied 1 week before and then 6 months and 1 year after the second surgery. Before this operation, unilateral tactile stimulation of either hand activated contralaterally the first (SI) and second (SII) somatosensory areas and the posterior parietal (PP) cortex, and SII and PP cortex ipsilaterally. All three tests were performed without errors. In both postoperative sessions, somatosensory activation was observed in contralateral SI, SII, and PP cortex, but not in ipsilateral SII and PP cortex. Performance was 100% correct in the TNT for the right hand, but below chance for the left; in the other tests, it was below chance except for TFLT in the intramanual task. This case provides the direct demonstration that activation of SII and PP cortex to stimulation of the ipsilateral hand and normal interhemispheric transfer of tactile information require the integrity of the posterior body of the CC.

Role of the corpus callosum in the somatosensory activation of the ipsilateral cerebral cortex: an fMRI study of callosotomized patients.

To verify whether the activation of the posterior parietal and parietal opercular cortices to tactile stimulation of the ipsilateral hand is mediated by the corpus callosum, a functional magnetic resonance imaging (fMRI, 1.0 tesla) study was performed in 12 control and 12 callosotomized subjects (three with total and nine with partial resection). Eleven patients were also submitted to the tactile naming test. In all subjects, unilateral tactile stimulation provoked a signal increase temporally correlated with the stimulus in three cortical regions of the contralateral hemisphere. One corresponded to the first somatosensory area, the second was in the posterior parietal cortex, and the third in the parietal opercular cortex. In controls, activation was also observed in the ipsilateral posterior parietal and parietal opercular cortices, in regions anatomically corresponding to those activated contralaterally. In callosotomized subjects, activation in the ipsilateral hemisphere was observed only in two patients with splenium and posterior body intact. These two patients and another four with the entire splenium and variable portions of the posterior body unsectioned named objects explored with the right and left hand without errors. This ability was impaired in the other patients. The present physiological and anatomical data indicate that in humans activation of the posterior parietal and parietal opercular cortices in the hemisphere ipsilateral to the stimulated hand is mediated by the corpus callosum, and that the commissural fibres involved probably cross the midline in the posterior third of its body.

Posttraumatic epilepsy risk factors: one-year prospective study after head injury.

PURPOSE: Prospective evaluation of risk factors for posttraumatic epilepsy (PTE) by using clinical, EEG, and brain computed tomography (CT) data in four assessments from the head injury (HI) acute phase to 1 year later; and evaluation of the possible epileptogenic role of hemosiderin as shown by brain magnetic resonance imaging (MRI). METHODS: Risk factors for PTE were evaluated by using Kaplan-Meier curves, log-rank test, and the Cox model in 137 consecutively enrolled adult inpatients. Percentage differences of patients with brain hyperintense and/or hemosiderin areas shown by MRI 1 year after HI were statistically evaluated by univariate tests considering two subgroups [e.g., patients with (PTE) and without (WLS) late seizures]. RESULTS: The PTE subgroup included 18 patients with at least two seizures between the second and twelfth months. Kaplan-Meier curves demonstrated that Glasgow Coma Scale low score, early seizures, and single brain CT lesions are PTE risk factors, as is the development of an EEG focus 1 month after HI. No significant percentage difference was found between PTE and WLS patients with hemosiderin spots shown by MRI 1 year after HI. CONCLUSIONS: the Cox model indicates that, for HI patients with early seizures and brain CT single temporal or frontal lesions in the acute phase, the PTE risk is 8.58 and 3.43 times higher, respectively, than for those without. An EEG focus 1 month after HI is a risk factor 3.49 times higher than for patients without such EEG changes. One year after HI, a higher percentage of PTE than WLS patients had cortical MRI hyper-intense areas including hemosiderin.

Localization of the first and second somatosensory areas in the human cerebral cortex with functional MR imaging.

BACKGROUND AND PURPOSE: Our objective was to map by means of a conventional mid-field (1.0 T) MR imaging system the somatosensory areas activated by unilateral tactile stimulation of the hand, with particular attention to the areas of the ipsilateral hemisphere. METHODS: Single-shot echo-planar T2*-weighted imaging sequences were performed in 12 healthy volunteers to acquire 10 contiguous 7-mm-thick sections parallel to the coronal and axial planes during tactile stimulation of the hand. The stimulation paradigm consisted of brushing the subjects' palm and fingers with a rough sponge at a frequency of about 1 Hz. RESULTS: Stimulation provoked a signal increase (about 2% to 5%) that temporally corresponded to the stimulus in several cortical regions of both hemispheres. Contralaterally, activation foci were in the anterior parietal cortex in an area presumably corresponding to the hand representation zone of the first somatosensory cortex, in the posterior parietal cortex, and in the parietal opercular cortex forming the upper bank of the sylvian sulcus and probably corresponding to the second somatosensory cortex. Activation foci were also observed in the frontal cortex. Ipsilaterally, activated areas were in regions of the posterior parietal and opercular cortices roughly symmetrical to those activated in the contralateral hemisphere. The same activation pattern was observed in all subjects. CONCLUSION: The activated areas of the somatosensory cortex described in the present study corresponded to those reported in other studies with magnetoelectroencephalography, positron emission tomography, and higher-field functional MR imaging. An additional area of activation in the ipsilateral parietal operculum, unnoticed in other functional MR imaging studies, was also observed.

Thrombolysis in ischemic stroke: evaluation of operative difficulties.

A few on-going international trials aim to investigate the effectiveness of early fibrinolytic treatment for ischaemic stroke to assist cerebral reperfusion. This operative strategy depends on clinical parameters such as haemorrhagic lesions, coma, pre-existent impairment and disability, and the efficiency of the sanitary organization receiving the patients (availability of CT scan, hospitalization within 6 h of onset of symptoms). We report data on the operative efficiency of a Regional Hospital Centre without a stroke unit: we observe that 142 patients did not receive early stroke treatment because of organizational problems whose prevalence exceeded the incidence of theoretical contraindications to fibrinolytic use. These elements suggest the necessity to organize a specific ward for the management of acute stroke.