Italian consensus recommendations for a biomarker-based aetiological diagnosis in mild cognitive impairment patients

BACKGROUND AND PURPOSE

Biomarkers support the aetiological diagnosis of neurocognitive disorders in vivo. Incomplete evidence is available to drive clinical decisions; available diagnostic algorithms are generic and not very helpful in clinical practice. The aim was to develop a biomarker-based diagnostic algorithm for mild cognitive impairment patients, leveraging on knowledge from recognized national experts.

METHODS

With a Delphi procedure, experienced clinicians making variable use of biomarkers in clinical practice and representing five Italian scientific societies (neurology - Società Italiana di Neurologia per le Demenze; neuroradiology - Associazione Italiana di Neuroradiologia; biochemistry - Società Italiana di Biochimica Clinica; psychogeriatrics - Associazione Italiana di Psicogeriatria; nuclear medicine - Associazione Italiana di Medicina Nucleare) defined the theoretical framework, relevant literature, the diagnostic issues to be addressed and the diagnostic algorithm. An N-1 majority defined consensus achievement.

RESULTS

The panellists chose the 2011 National Institute on Aging and Alzheimer's Association diagnostic criteria as the reference theoretical framework and defined the algorithm in seven Delphi rounds. The algorithm includes baseline clinical and cognitive assessment, blood examination, and magnetic resonance imaging with exclusionary and inclusionary roles; dopamine transporter single-photon emission computed tomography (if no/unclear parkinsonism) or metaiodobenzylguanidine cardiac scintigraphy for suspected dementia with Lewy bodies with clear parkinsonism (round VII, votes (yes-no-abstained): 3-1-1); ¹⁸ F-fluorodeoxyglucose positron emission tomography for suspected frontotemporal lobar degeneration and low diagnostic confidence of Alzheimer's disease (round VII, 4-0-1); cerebrospinal fluid for suspected Alzheimer's disease (round IV, 4-1-0); and amyloid positron emission tomography if cerebrospinal fluid was not possible/accepted (round V, 4-1-0) or inconclusive (round VI, 5-0-0).

CONCLUSIONS

These consensus recommendations can guide clinicians in the biomarker-based aetiological diagnosis of mild cognitive impairment, whilst guidelines cannot be defined with evidence-to-decision procedures due to incomplete evidence.

Diffusion-Weighted and Diffusion Tensor Magnetic Resonance Brain Imaging: Principles and Applications

Diffusion Weighted Imaging (DWI) is one of the most recent products of Magnetic Resonance (MR) technology evolution. DWI has been proposed as a noninvasive tool for evaluating structural and physiologic states in biologic tissues as hyperacute ischemic changes within brain tissue. Recently, its more complex and detailed evolution, Diffusion Tensor Imaging (DTI), has been introduced and its clinical applications are the evaluation of anatomical structures and pathologic processes in white matter. White matter quantitative maps that indicate the integrity of brain tissue, color map, and tractography that identifies macroscopic three-dimensional architecture of fiber tracts (e.g., projections and association pathways) can be obtained with DTI.

Diffusion weighted imaging visualization techniques (ADC and Trace) are applied for the study of stroke, in the differential diagnosis of expansive lesions (e.g. epidermoid vs. arachnoid cyst) and in detecting traumatic and other lesions associated with restricted diffusion (e.g. MS plaques). On the other hand, DTI provides the identification of abnormalities in the otherwise normal appearing white matter with the understanding of the organization of the fibers, both in tumors and in other cortical or white matter diseases (including stroke, dementias, demyelinating-dismyelinating diseases, epilepsy, schizophrenia). Furthermore, in combination with functional MR, DTI might contribute to the comprehension of brain development, aging and connectivity, thus having a significant impact on brain functional studies.

La mielopatia in corso di artrite reumatoide a localizzazione cervicale

In corso di artrite reumatoide l'interessamento del rachide cervicale riguarda circa il 60–70% dei pazienti affetti dalla patologia. Le strutture colpite dalla flogosi reumatoide sono le articolazioni cartilaginee e sinoviali, le cosiddette articolazioni di Luschka, l'inserzione di tendini e legamenti e i tessuti molli della regione cervicale. Il coinvolgimento del tratto cervicale può essere asintomatico o rendersi responsabile di importante dolore, limitazione funzionale e di varie manifestazioni neurologiche, quali parestesie, paresi, ipotrofia muscolare, fino alla quadriplegia e morte, soprattutto in caso di malattia particolarmente aggressiva e perdurante da molto tempo.

In questo lavoro si è cercato di individuare i caratteri clinico-radiologici più significativamente associati a sintomatologia neurologica in corso di artrite reumatoide. Particolare attenzione è stata prestata per definire i caratteri morfologici ed il valore degli indici lineari indicatori di compressione midollare per lussazione atlo-assiale.

Dei 27 pazienti (24 donne e 3 uomini, età media di 61 anni) appartenenti alla casistica in esame, solo 3 (11,1%) presentavano esclusivo interessamento del tratto sub-assiale; 19 (70,3%) presentavano esclusivo interessamento radiologico della cerniera atlo-assiale, mentre in 5 (18,6%) era rilevabile coinvolgimento radiologico sia del tratto sub-assiale che della cerniera.

In base alla nostra esperienza, più della metà di questi pazienti sviluppa lussazione atlo-assiale; di questi, a loro volta, circa la metà presenta interessamento neurologico: è a questo gruppo, in cui più frequentemente ricorre la lussazione anteriore pura (nel 57% dei casi, contro il 37,5% di quelli privi di interessamento neurologico), cui deve essere prestata particolare attenzione in quanto suscettibile di trattamento chirurgico decompressivo (odontoidectomia) che può eliminare la causa di compressione midollare altrimenti destinata a «fissarsi» in maniera irreversibile con conseguenti gravissimi disturbi neurologici.

Questo gruppo di pazienti, in base alla nostra casistica, comprende una relativa maggior rappresentazione del sesso maschile, ed una durata media di malattia significativamente inferiore, con conseguente più breve periodo di accertata positività al FR; anche l'età media è significativamente inferiore, situandosi attorno ai 58 anni contro i 64,9 dei pazienti senza interessamento neurologico.

In questi pazienti il valore critico di 9 mm di distanza atlo-dentale è stato raggiunto e superato in più della metà dei casi, contro solo il 12,5% dei pazienti senza interessamento neurologico. Parimenti, più frequente è risultata la presenza di cospicuo panno infiammatorio; l'iper-intensità midollare, spia di mielopatia, è stata osservata solo in questi pazienti, nell'86% dei quali l'angolo bulbo-midollare era ristretto per impronta compressiva esercitata dal dente dell'epistrofeo.

La RM si è dimostrata eccellente strumento diagnostico per la valutazione del coinvolgimento del rachide cervicale in corso di artrite reumatoide: è l'unica indagine, infatti, che consente contemporaneamente la visualizzazione diretta del panno infiammatorio, del coinvolgimento del legamento trasverso e dei segni della mielopatia da compressione midollare.

Ependymoma with diffuse signet-ring features: report of a case and review of the literature

Signet-ring cell ependymoma is a rare variant of ependymoma with only seven cases described in literature. Biological behavior and prognosis of this entity are not well-known until now. We present a case of a 49-year-old female with a history of headache and gait instability. Magnetic resonance imaging showed an upper cervical tumor with cystic component and mural nodule. The patient underwent surgery. Microscopically some cells displayed an eccentric nucleus compressed to the periphery by vacuolated cytoplasm. Perivascular pseudorosettes and ependymal rosettes were seen only focally. The cells were positive for glial fibrillary acidic protein and epithelial membrane antigen. The diagnosis was ependymoma with diffuse signet-ring features, grade II according to the World Health Organization. It may be difficult to diagnose this unusual variant of ependymoma especially on small biopsies or frozen sections. A complete examination of the specimen is recommended with immunohistochemical confirmation to rule out potential morphologic mimics, such as metastatic adenocarcinomas and gliomas in the differential diagnosis.

Effect of median-nerve electrical stimulation on BOLD activity in acute ischemic stroke patients

OBJECTIVE

To investigate blood oxygenation level-dependent (BOLD) activation during somatosensory electrical stimulation of the median nerve in acute stroke patients and to determine its correlation with ischemic damage and clinical recovery over time.

METHODS

Fourteen acute stroke patients underwent functional magnetic resonance imaging (fMRI) during contralesional median-nerve electrical stimulation 12-48 h after stroke. Findings were then validated by diffusion tensor imaging (DTI) and motor evoked potential by transcranial magnetic stimulation (TMS).

RESULTS

Poor clinical recovery at three months was noted in four patients with no activation in the early days after stroke, whereas good clinical recovery was observed in eight patients with a normal activation pattern in the primary sensory motor area in the acute phase. In two patients BOLD activation correlated weakly with clinical recovery. Findings from TMS and DTI partially correlated with clinical recovery and functional scores.

CONCLUSIONS

Clinically relevant insights into the "functional reserve" of stroke patients gained with peripheral nerve stimulation during fMRI may carry prognostic value already in the acute period of a cerebrovascular accident.

SIGNIFICANCE

BOLD activation maps could provide insights into the functional organization of the residual systems and could contribute to medical decision making in neurological and rehabilitative treatment.

Local amygdala structural differences with 3T MRI in patients with Alzheimer disease

OBJECTIVE

Histologic studies show that the amygdala is affected by Alzheimer disease (AD) pathology, and its medial aspect is the most involved. We aimed to assess in vivo local structural differences in the amygdala of patients with AD using high-field MRI.

METHODS

A total of 19 patients with AD (mean age 76, SD 6 years, mean Mini-Mental State Examination score [MMSE] 13, SD 4) and 19 healthy elderly controls (age 74, SD 5, MMSE 29, SD 1) were enrolled. The radial atrophy mapping technique was used to reconstruct the 3-dimensional surface of the amygdala. Maps of surface tissue loss in patients with AD vs controls were computed and statistically tested with permutation tests thresholded at p < 0.05, to correct for multiple comparisons. A digital atlas of the amygdalar nuclei was used to infer which nuclei were involved.

RESULTS

Both amygdalar volumes were significantly smaller in patients with AD (right 1,508 mm³, SD 418; left 1,646, SD 419) than controls (right 2,129 mm³, SD 316; left 2,077, SD 376; p < 0.002). In the dorsomedial part, significant local tissue loss (20%-30%) was mapped in the medial and central nuclei. Ventrally, the lateral nucleus (La) and the basolateral ventral medial nucleus (BLVM) were also involved (20%-30% loss).

CONCLUSIONS

We found in vivo local structural differences in the amygdala of patients with AD. The nuclei involved have known connections to the hippocampus (BLVM, La) and olfactory system (medial nucleus) and with cholinergic pathways (central nucleus). This pattern is consistent with the known pathophysiology of neural systems affected by AD.

Clinical target volume delineation in glioblastomas: pre-operative versus post-operative/pre-radiotherapy MRI

OBJECTIVES

Delineation of clinical target volume (CTV) is still controversial in glioblastomas. In order to assess the differences in volume and shape of the radiotherapy target, the use of pre-operative vs post-operative/pre-radiotherapy T(1) and T(2) weighted MRI was compared.

METHODS

4 CTVs were delineated in 24 patients pre-operatively and post-operatively using T(1) contrast-enhanced (T1(PRE)CTV and T1(POST)CTV) and T(2) weighted images (T2(PRE)CTV and T2(POST)CTV). Pre-operative MRI examinations were performed the day before surgery, whereas post-operative examinations were acquired 1 month after surgery and before chemoradiation. A concordance index (CI) was defined as the ratio between the overlapping and composite volumes.

RESULTS

The volumes of T1(PRE)CTV and T1(POST)CTV were not statistically different (248 ± 88 vs 254 ± 101), although volume differences >100 cm(3) were observed in 6 out of 24 patients. A marked increase due to tumour progression was shown in three patients. Three patients showed a decrease because of a reduced mass effect. A significant reduction occurred between pre-operative and post-operative T(2) volumes (139 ± 68 vs 78 ± 59). Lack of concordance was observed between T1(PRE)CTV and T1(POST)CTV (CI = 0.67 ± 0.09), T2(PRE)CTV and T2(POST)CTV (CI = 0.39 ± 0.20) and comparing the portion of the T1(PRE)CTV and T1(POST)CTV not covered by that defined on T2(PRE)CTV images (CI = 0.45 ± 0.16 and 0.44 ± 0.17, respectively).

CONCLUSION

Using T(2) MRI, huge variations can be observed in peritumoural oedema, which are probably due to steroid treatment. Using T(1) MRI, brain shifts after surgery and possible progressive enhancing lesions produce substantial differences in CTVs. Our data support the use of post-operative/pre-radiotherapy T(1) weighted MRI for planning purposes.

Updates in the determination of brain death

The concept of brain death must be accurately determined and defined, especially in the light of the latest legislation on brain blood flow measurements.

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.

Operative classification of brain arteriovenous malformation. Part two: validation

SUMMARY

The most important issue when dealing with a patient with a brain AVM is the decision whether to treat or not. Only after this decision has been made, taking into consideration a number of factors depending on both the patient and the specific type of AVM, can the best option for treatment be chosen. An operative classification of brain AVMs, previously adopted in the Department of Neuroradiology and Neurosurgery of Verona (Italy) and published in this journal, was subjected to validation in a consecutive group of 104 patients clinically followed for at least three years after completion of treatment. This classification, slightly modified from the original version concerning the importance of some specific items, allowed us to assess the indication to treat in each case, whatever type of treatment was offered to the patient.

Review of corpus callosum topography, analysis of diffusion values for the different callosal fibers and sex differences

Conventional MRI shows the morphology of the corpus callosum (CC), but does not reveal cortical connectivity or structural information on the CC. Here, we applied diffusion tensor imaging (DTI) in conjunction with a tract-tracing algorithm to incorporate cortical connectivity information on the CC in 40 subjects and to detect the main area and sex structural differences. CC parcellation was based on trajectories to different cortical (prefrontal, frontal motor/premotor/supplementary motor connections, parieto-occipital, temporal) and sub-cortical areas (capsular/basal ganglia connections). In agreement with recent DTI studies, we found that motor fibers occupy a much larger portion of the CC than previously believed on the basis of anatomical data. Differences in anisotropy values were instead in agreement with previous morphological evidence of smaller fibers in the anterior and posterior portions of the CC. The main sex difference was observed in anisotropy values in frontal fibers that proved to be lower in females than in males. Statistically significant differences in the regional diffusion parameters and between sexes give rise to many important questions regarding fiber organization patterns, CC microstructure and the functional relevance of these differences and provide evidence for the role of DTI, which reaches beyond the information given by morphological analysis.

f-MRI in Epilepsy with Spike and Wave Activity Evoked by Eye Closure: Different Bold Activation in a Patient with Idiopathic Partial Epilepsy with Occipital Spikes and a Control Group

We performed functional magnetic resonance imaging (fMRI) in a 30-year-old man with idiopathic partial epilepsy with occipital spikes whose scalp EEG activity was characterized by persistent epileptiform discharges on eye closure, ceasing upon eye opening. We compared BOLD activation in the patient and in a control group of three normal volunteers. f-MRI showed that occipital cortex and frontal areas were activated in relation to eye movement in normal subjects during eye opening but not during eye closing. While persistent interictal spike and wave activity was present over the posterior and anterior scalp in the patient upon eye closing, f-MRI showed bilateral activation of the parietal and temporal regions. This fMRI study documents the activation of posterior and temporal areas related to continuous intercritical spikes evoked by eye closure, which are diffuse over the scalp. This activation was absent in the control group during eye closure.

Structural correlates of early and late onset Alzheimer's disease: voxel based morphometric study

OBJECTIVE

To examine the brain structural correlates of age at onset in patients with Alzheimer's disease.

METHODS

We studied nine patients with early onset (age < or =65 years), nine with late onset (age > 65) Alzheimer's disease (EOAD and LOAD, respectively) of mild-moderate severity, and 26 controls who were stratified into younger (YC, age < or =65, n = 9) and older (OC, age > 65, n = 17) subjects. The patients were closely matched for clinical severity: 3/2/3/1 patients had clinical dementia rating of 0.5/1/2/3, respectively, in both the groups. High resolution magnetic resonance images of the brain of the EOAD and YC groups and the LOAD and OC groups were compared on a voxel by voxel basis with statistical parametric mapping to detect areas specifically atrophic.

RESULTS

The patients with EOAD showed greater neocortical atrophy at the temporoparietal junction while the patients with LOAD showed greater hippocampal atrophy. The results could not be accounted for by the apolipoprotein E genotype.

CONCLUSIONS

Since genetic factors are believed to play a relevant pathogenetic role in EOAD and environmental factors in LOAD, genetic and environmental factors may differentially predispose the neocortical and limbic areas to the development of Alzheimer's neuropathology.

APOE and modulation of Alzheimer's and frontotemporal dementia

To investigate the difference in the morphologic expression of frontotemporal dementia (FTD) and Alzheimer's disease (AD) in patients carrying and not carrying the epsilon4 allele of APOE, MR images of 26 controls, 18 AD patients (11 carrying the epsilon4 allele, seven non-carriers), and eight FTD (two carriers, six non-carriers) were compared using voxel by voxel analysis. Greater atrophy was found in the disease-specific regions of the epsilon4 carriers vs the non-carriers at P < 0.05 corrected: medial temporal atrophy was greater in the AD carrying the epsilon4 allele, right ventral striatal atrophy in the FTD carrying the allele. The non-carriers did not have atrophic regions compared to the carriers. The epsilon4 allele of the APOE might modulate the expression of degenerative dementias by enhancing the specific effects of neurodegenerative diseases on the brain.

Detection of grey matter loss in mild Alzheimer's disease with voxel based morphometry

OBJECTIVES

To test the applicability of an automated method of magnetic resonance image analysis (voxel based morphometry) to detect presence and severity of regional grey matter density reduction-a proxy of atrophy-in Alzheimer's disease.

METHODS

Twenty nine probable Alzheimer's patients and 26 non-demented controls (mini-mental state examinations mean (SD) 21 (4) and 29 (1)) underwent high resolution 3D brain magnetic resonance imaging. Spatial normalisation to a stereotactic template, segmentation into grey matter, white matter, and cerebrospinal fluid, and smoothing of the grey matter were carried out based on statistical parametric mapping (SPM99) algorithms. Analyses were carried out: (a) contrasting all Alzheimer's patients with all controls (p<0.05 corrected for multiple comparisons); (b) contrasting the three Alzheimer's patients with mini-mental state of 26 and higher with all controls (p<0.0001 uncorrected); and (c) correlating grey matter density with mini-mental state score within the Alzheimer's group (p<0.0001 uncorrected).

RESULTS

When all Alzheimer's patients were compared with controls, the largest atrophic regions corresponded to the right and left hippocampal/amygdalar complex. All parts of the hippocampus (head, body, and tail) were affected. More localised atrophic regions were in the temporal and cingulate gyri, precuneus, insular cortex, caudate nucleus, and frontal cortex. When the mildest Alzheimer's patients were contrasted with controls, the hippocampal/amygdalar complex were again found significantly atrophic bilaterally. The mini-mental state score correlated with grey matter density reduction in the temporal and posterior cingulate gyri, and precuneus, mainly to the right.

CONCLUSIONS

Voxel based morphometry with statistical parametric mapping is sensitive to regional grey matter density reduction in mild Alzheimer's disease.

Spinal dysraphism in an elderly patient

Spinal dysraphisms are diagnosed more frequently at birth or in infancy. We report a spinal malformation compatible with lipomyeloschisis in an elderly patient presenting with symptoms and signs of myelopathy. Magnetic resonance imaging revealed an intraspinal mass continuous with a subcutaneous lipoma. Three-dimensional computed tomography reconstructions better showed the spinal dysraphism; dermal sinus was also evident. Neuroimaging can define the precise diagnosis also in elderly patients presenting with myelopathy and can provide valuable structural details.

Hippocampus and entorhinal cortex in frontotemporal dementia and Alzheimer's disease: a morphometric MRI study

BACKGROUND

Magnetic resonance imaging (MRI) of hippocampal atrophy is a sensitive but not specific method to support the clinical diagnosis of early Alzheimer's disease (AD). We recently described our findings that atrophy of the entorhinal cortex (ERC) in frontotemporal dementia (FTD) is equal to that found in AD but that hippocampal atrophy in FTD is less than that found in AD. The MRI volumes of these structures provide a topographic representation of the region of interest. We hypothesized that two different dementias with distinct histopathologic and clinical features might, in addition to quantitative patterns, display topographically different patterns of atrophy.

METHODS

We adopted a morphometric approach to monitor the pattern of atrophy of the hippocampus and the ERC by computing two-dimensional profiles from MRI volumes of the structures in control subjects and patients with FTD and AD.

RESULTS

Compared with control subjects, atrophy of the hippocampus in patients with AD was diffuse. In patients with FTD, atrophy of the hippocampus was localized predominantly in the anterior hippocampus, suggesting a different pattern of hippocampal atrophy in FTD compared with AD. The amount and pattern of atrophy of the entorhinal cortex was virtually equal in both demented groups.

CONCLUSIONS

This study provides novel data on the nature of medial temporal lobe atrophy in FTD. Morphometric MRI may be a useful technique for characterizing different patterns of atrophy in primary degenerative dementias in vivo.

Apolipoprotein E genotype and hippocampal asymmetry in Alzheimer's disease: a volumetric MRI study

Asymmetry of brain structures is common to many species and is even present in utero. Some developmental, pathological, and dementing diseases are associated with alterations in normal anatomical asymmetries. Anatomical asymmetries, however, have been only superficially studied in Alzheimer's disease. Recent evidence indicates that the allele epsilon4 of the apolipoprotein E (ApoE), a well known risk factor for Alzheimer's disease, might play a part in determining some brain morphological changes both in normal carriers and in patients with Alzheimer's disease. This study evaluated the effect of the ApoE genotype on hippocampal asymmetry in patients with Alzheimer's disease carrying 0, 1, and 2 copies of the allele. Volumetric right-left differences of the hippocampi were computed in 28 right handed patients with Alzheimer's disease (14 -/-, 9 epsilon4/-, and 5 epsilon4/4) and 30 controls without detectable cognitive deficit. In controls, the right hippocampus was larger than the left, whereas in patients with Alzheimer's disease this asymmetry was progressively reduced with increasing gene dose of the epsilon4 allele, and the asymmetry was reversed in the epsilon4/4 Alzheimer's disease group. The mean right-left volume differences were: 1.2, 0.7, 0.2, and -1.0 in controls, -/-, epsilon4/-, and epsilon4/4 patients, respectively (sex adjusted p for trend=0.017). The data indicate a dose dependent effect of the ApoE epsilon4 allele on hippocampal volume asymmetry in Alzheimer's disease.

APOE-epsilon4 is associated with less frontal and more medial temporal lobe atrophy in AD

OBJECTIVE

To test the hypothesis that the e4 allele of APOE is associated with a region-specific pattern of brain atrophy in AD.

METHODS

Volumes of the hippocampi, entorhinal cortices, and anterior temporal and frontal lobes were measured in 28 mild to moderate AD patients and 30 controls using MRI. Within the AD group, 14 patients were noncarriers (-/-), 9 were heterozygous (e4/-), and 5 were homozygous (e4/4) for the e4 allele. Dementia severity was similar across the three AD groups.

RESULTS

Smaller volumes were found with increasing dose of the e4 allele in the hippocampus, entorhinal cortex, and anterior temporal lobes in AD patients. When compared with controls, the volume loss in the right and left temporal regions ranged from -15.3 to -22.7% in the -/- AD group, from -26.2 to -36.0% in the e4/- group, and from -24.0 to -48.0% in the e4/4 group (p < 0.0005). In contrast, larger volumes were found in the frontal lobes with increasing e4 gene dose. When compared with controls, volume differences of the right frontal lobe were -11.8% in the -/- AD group, -8.5 in the e4/- group, and -1.4% in the e4/4 group (p = 0.03).

CONCLUSIONS

We found smaller volumes in the temporal lobe regions but larger volumes in the frontal lobes with increasing APOE-e4 gene dose in AD patients. These data suggest a region-specific biological effect of the e4 allele in the brains of AD patients.

Superficial siderosis of the central nervous system and anticoagulant therapy: a case report

Superficial siderosis of the central nervous system is a rare condition characterized by deposition of haemosiderin in the leptomeninges and in the subpial layers of the brain and spinal cord. With the widespread use of magnetic resonance imaging, an increasing number of cases of superficial siderosis are being discovered, secondary forms being more frequent than idiopathic ones. We report a 78-year-old man in oral anticoagulant therapy, who presented neurosensory hearing loss, gait ataxia and spastic paraparesis. Magnetic resonance imaging suggested the diagnosis of superficial siderosis of the central nervous system, without an evident bleeding source.

Does the tuberous sclerosis complex include intracranial aneurysms? A case report with a review of the literature

BACKGROUND

Tuberous sclerosis is a protean, genetically determined disease that may involve any organ or tissue and lead to a great number of symptoms and clinical features.

OBJECTIVE

Diagnosis can be very difficult in cases with incomplete manifestations (formes fruste) lacking the classic signs of the disease.

MATERIALS AND METHODS

We report a case fulfilling the diagnostic criteria for tuberous sclerosis (shagreen patches, hypomelanotic macules, renal cysts and angiomyolipomas, and "migration tracts" in the cerebral white matter) in association with a giant intracranial aneurysm, but lacking mental retardation, epilepsy and facial angiofibroma.

RESULTS

Fourteen other cases of tuberous sclerosis and intracranial aneurysms, all but one without any clear sign of polycystic kidney disease, were found in the literature.

CONCLUSION

We suggest that vascular dysplasias in general and aneurysms (mainly intracranial) in particular can be added to the other non-primary diagnostic features for the clinical diagnosis of tuberous sclerosis.

Hippocampal and entorhinal cortex atrophy in frontotemporal dementia and Alzheimer's disease

OBJECTIVE

To describe atrophic changes of the hippocampus and entorhinal cortex in frontotemporal dementia (FTD) and compare them with those of AD.

BACKGROUND

The medial temporal lobe shows atrophic changes early in the course of AD, but whether these changes are specific to AD or occur in other degenerative dementias, and to what extent, is unclear.

METHODS

The authors measured the volumes of the left and right hippocampus and entorhinal cortex from MR images (1.5 T, 2-mm-thick slices) in 12 patients with FTD, 30 with AD, and 30 elderly control subjects.

RESULTS

In FTD patients, the left and right hippocampus (16% and 21% tissue loss) and the entorhinal cortex (28% and 27% loss) were more atrophic than the control subjects. Atrophy of the hippocampus in FTD was less severe than in AD, but atrophy of the entorhinal cortex was equally severe. Greater hippocampal and entorhinal cortex atrophy was present in the most severe patients in both groups (as high as a 49% tissue loss). The sensitivity of the hippocampus and the entorhinal cortex to discriminate FTD patients from control subjects was low (49% and 52%, respectively; specificity set at 90%), whereas hippocampal volumes could better differentiate AD patients from control subjects (80% sensitivity).

CONCLUSIONS

At variance with AD, detectable in vivo atrophy of the hippocampus might not be an early event in FTD. Differential patterns of atrophy might help in the diagnostic process of the degenerative dementias.

Paradoxically greater interhemispheric transfer deficits in partial than complete callosal agenesis

Symptoms of interhemispheric disconnection are typically much less severe in callosal agenesis than after surgical section of the corpus callosum. Sperry [Sperry, R. W., Plasticity of neural maturation. Developmental Biology, 1968, 2 (Suppl.), 306-327.] has attributed this difference to two interconnected factors: (1) the callosal section is usually performed after the brain has lost the maximal degree of functional plasticity associated with the early stages of development and (2) the removal of an already formed structure is more disruptive for functional brain organization than the failure of the same structure to develop. It has been suggested that functional compensation is less efficient if callosal agenesis is partial rather than complete [Dennis, M., Impaired sensory and motor differentiation with corpus callosum agenesis: A lack of callosal inhibition during ontogeny? Neuropsychologia, 1976, 14, 455-469.]. This suggestion is supported by the present findings of partial left-hand anomia, partial left-field alexia and poor tactile cross-localization in a subject with a congenital absence of the posterior part of the corpus callosum due to an arteriovenous malformation. In agreement with many previous studies, similar, though more severe, symptoms of interhemispheric disconnection were found in a subject with a complete section of the corpus callosum, but not in a subject with complete callosal agenesis. Praxic control of the left hand on verbal commands was severely deficient in the callosotomy subject, but it was normal in the subject with callosal hypogenesis. The lesser degree of compensation in partial compared to complete callosal agenesis may be explained by a reduced pressure to develop extracallosal means of interhemispheric communication, contingent on the partial existence of callosal connections, as well as by the later occurrence in development of the causes of callosal hypogenesis compared to those of total callosal agenesis.

Neuropsychological and neuroimaging correlates in corticobasal degeneration

The aim of this study was to correlate neuropsychological and neuroimaging findings in corticobasal degeneration (CBD). Three patients with clinical criteria for CBD were examined by means of neuropsychological tests, brain magnetic resonance imaging (MRI), and flow and metabolism neuroimaging techniques. Neuropsychological assessment revealed impairment in executive functions, manual dexterity and motor programming with significant asymmetry between upper limbs. Ideomotor and oral apraxia were also detected, and memory deficits were observed in one patient. MRI revealed cortical dilation of the frontal and peri-rolandic regions, symmetrical in one case and asymmetrical in the other two cases. An increased T2 signal intensity in the posterolateral putamen and substantia nigra ipsilateral to the cortical atrophy was observed in one patient. Asymmetries of both frontal and parietal cortices and basal ganglia were detected in all three patients by 18-fluorodeoxyglucose positron emission tomography; temporal region hypometabolism was associated in one patient. These cortical and subcortical asymmetries were observed in two patients by single photon emission tomography with the tracer technetium Tc 99m hexamethyl propylenamine oxime; cortical asymmetry was observed in only one patient. The results showed that functional neuroimaging findings correlated well with neuropsychological aspects in CBD. Neuroimaging and neuropsychological correlations may contribute toward understanding anatomical and functional abnormalities associated with this neurodegenerative disorder.

Fossa navicularis magna

A notchlike bone defect in the basiocciput due to a prominent fossa navicularis was incidentally discovered in a patient referred for radiologic evaluation of sinusitis. MR images showed that the osseous defect was filled with lymphoid tissue of the pharyngeal tonsil. The occurrence of this anatomic variant is discussed, with reference to ancient anatomic works.

Motor representation of the hand in the human cortex: an f-MRI study with a conventional 1.5 T clinical unit

The purpose of this study was to show a gradient of possible bilateral activation for movements of the non-dominant vs. dominant hand, as well as for areas involved in complex vs. simple hand movements. A standard 1.5 T magnetic resonance imaging (MRI) system has been utilized to localize the cortical motor hand areas, using the blood oxygen level dependent contrast (BOLDc) technique and single-section fast low-angle shot (FLASH) imaging. Ten normal right-handed subjects volunteered for the study. The motor tasks consisted of simple (flexion-extension) finger movements of either hand, and complex movements (finger-to-thumb opposition in a repeating, pre-planned sequence) of the non-dominant hand. Simple movements caused contralateral activation of the primary motor area (MA); ipsilateral activation was observed for the non-dominant hand only. Supplementary motor area (SMA) was also activated, with a clear contralateral prevalence. The ratio of bilateral activation of MA did not change with complex movements of the non-dominant hand, while SMA as well as lateral premotor area were largely bilaterally activated in this task. In conclusion, the ipsilateral MA is activated for movements--even simple--performed with the non-dominant hand. There is widespread functional activity, involving both contralateral and ipsilateral SMA, for complex movements.

Intracranial myxoid chondrosarcoma with early intradural growth

Chondrosarcomas are extremely rare intracranial cartilaginous tumors of which the myxoid variant is the least reported in the literature. They develop extradurally and generally infiltrate the dura only in advanced stages or at recurrence. We describe the case of a 55-year-old woman with a posterior cranial fossa myxoid chondrosarcoma which had a primarily intradural extension.

Spike topography and functional magnetic resonance imaging (fMRI) in benign rolandic epilepsy with spikes evoked by tapping stimulation

We performed a spike topography study and a functional magnetic resonance imaging (fMRI) in a female patient with benign rolandic epilepsy presenting single high-amplitude evoked spikes in response to somatosensory peripheral stimulation. The stimulus was delivered to the first finger of the right hand using a tendon hammer, which evoked a single spike followed by a slow wave, showing the maximal amplitude over the left central regions. fMRI showed that the contralateral sensory cortices (S1 and S2) and the motor cortex (M I) were activated during tapping stimulation. In 3 normal subjects, tapping stimulation produced no fMRI activation. This fMRI study documents a highly focal activation of sensorimotor areas related to subclinical evoked spikes in benign rolandic epilepsy.

Computed tomography and magnetic resonance imaging in the management of coronoid process hyperplasia: review of five cases

OBJECTIVE

To describe the imaging features of primary bilateral coronoid hyperplasia, with particular reference to the use of CT and MRI.

MATERIALS

A series of five cases is reviewed.

RESULTS

The correct diagnosis was achieved with panoramic radiography alone or with the addition of CT. MRI did not provide additional pre-operative information; it was useful in the postoperative assessment of poor functional recovery in order to determine the presence of haematoma and/or fibrosis.

CONCLUSIONS

Although panoramic radiography alone can demonstrate this condition, CT has an important role in diagnosis and is useful for an adequate surgical planning by allowing assessment of the size of impingement of the coronoid processes. MRI is useful for evaluating postoperative complications involving soft tissue.