Alterazioni meningee da ipotensione liquorale essenziale

Gli autori descrivono un caso di ipotensione liquorale essenziale con sindrome clinica ad esordio acuto, costituita da cefalea gravativa che si riduceva parzialmente in decubito orizzontale, regredita in cinque mesi. Vari esami RM dimostrarono la presenza di un ispessimento durale con accentuazione dopo contrasto, sia in sede endocranica che a livello cervicale, ed anche un sottile e circoscritto scollamento durale con lievi fenomeni emorragici; alla remissione clinica si accompagnò la normalizzazione del quadro neuroradiologico. Vengono discussi i possibili meccanismi patogenetici delle alterazioni durali alla luce dell'anatomia degli strati profondi della dura e ne vengono sottolineati gli aspetti radiologici.

La risonanza magnetica nelle encefalomiopatie mitocondriali

Le encefalopatie mitocondriali sono un gruppo eterogeneo di malattie, in parte ancora in corso di definizione, per cui è sempre necessaria una conferma biochimica.

Alcune malattie mitocondriali, come i difetti della β- ossidazione degli acidi grassi, possono causare gravi squilibri metabolici con ipoglicemia e coma che si ripercuotono in modo aspecifico sul sistema nervoso centrale determinando quadri di sofferenza cerebrale diffusa. Altre malattie mitocondriali determinano danni più specifici sul SNC. Nella prima infanzia la malattia più caratteristica è la malattia di Leigh, che determina alterazioni principalmente nel tegmento pontino e mesencefalico e nei nuclei della base. Alcuni casi presentano lesioni caratteristiche nei nuclei subtalamici, altri presentano reperti più aspecifici e diffusi simili a quadri di leucodistrofia.

In età più tardiva (seconda infanzia o età adulta) la malattia più interessante dal punto di vista neuroradiologico è il MELAS, che presenta lesioni cortico-sottocorticali nelle regioni posteriori con distribuzione non tipicamente vascolare, sopra e sottotentoriali, che tuttavia possono essere ricondotte ai territori più distali dei vasi. Calcificazioni nei nuclei della base sono presenti in circa la metà dei casi.

Un'altra encefalopatia mitocondriale dell'età giovanile o adulta è la sindrome di Kearns-Sayre, in cui la RM può dimostrare alterazioni nel tronco, nei talami, nei nuclei della base e nella sostanza bianca sottocorticale.

Alterazioni nel neostriato possono essere osservate nelle sindromi distoniche associate ad atrofia ottica di Leber. Non sono descritte invece lesioni specifiche nel MERRF, in cui atrofia ed alterazioni della sostanza bianca sono state occasionalmente osservate. Esistono infine casi che presentano quadri clinici e neuroradiologici intermedi tra le varie sindromi mitocondriali.

L'obiettivo di questa revisione è dimostrare alcuni aspetti tipici delle sindromi più comuni e indicare quali aspetti neuroradiologici, a volte inattesi, devono suggerire l'ipotesi di encefalopatia mitocondriale, permettendo cosi di indirizzare in modo corretto ulteriori indagini diagnostiche.

White matter involvement in idiopathic Parkinson disease: a diffusion tensor imaging study

BACKGROUND AND PURPOSE

Diffusion tensor imaging (DTI) offers a unique window on the connectivity changes, extending beyond the basal ganglia, which accompany the cognitive symptoms of Parkinson disease (PD). The primary purpose of this study was to assess the microstructural damage to cerebral white matter occurring in idiopathic PD.

MATERIALS AND METHODS

Our sample included patients with PD without dementia (n = 10; Hoehn and Yahr stages I and II; Unified Parkinson Disease Rating Scale, 20.5 +/- 8.3; and Mini-Mental State Examination, 28.3 +/- 1.5) and age-matched healthy control subjects (n = 10). DTI was performed on a 1.5T scanner, and mean diffusivity (MD) and fractional anisotropy (FA) maps were obtained. Regions of interest (ROIs) were drawn on the major fiber bundles as well as on gray matter nuclei.

RESULTS

In patients, the MD was increased at borderline significance in the substantia nigra but was unaltered in the thalamus, globus pallidus, putamen, and in the head of the caudate nucleus. The FA and MD were unaltered in the corticospinal tract in the midbrain and at the level of the internal capsule, and in the splenium of the corpus callosum. By contrast, the MD was increased and the FA was decreased in the genu of the corpus callosum and in the superior longitudinal fasciculus; in the cingulum, only the MD was altered. The observed changes were not significantly lateralized.

CONCLUSIONS

Widespread microstructural damage to frontal and parietal white matter occurs already in the early stages of PD.

Optimization and validation of an automated voltammetric stripping technique for ultratrace metal analysis

A new automated batch method for the determination of ultratrace metals (nanogram per liter level) was developed and validated. Instrumental and chemical parameters affecting the performance of the method were carefully assessed and optimized. A wide range of voltammetric methods under different chemical conditions were tested. Cadmium, lead and copper were determined by anodic stripping voltammetry (ASV), while nickel, cobalt, rhodium and uranium by adsorptive cathodic stripping voltammetry (AdCSV). The figures of merit of all of these methods were determined: very good precision and accuracy were achieved, e.g. relative percentage standard deviation in the 4-13% for ASV and 2-5% for AdCSV. The stripping methods were applied to the determination of cadmium, lead, copper, nickel, cobalt, rhodium and uranium in lake water samples and the results were found to be comparable with ICP-MS data.

Obliteration of a giant fusiform carotid terminus-M1 aneurysm after distal clip application and extracranial-intracranial bypass. Case report

Giant intracranial aneurysms may not be amenable to direct surgical clipping or endovascular coiling because of three critical factors: 1) lack of clear aneurysmal neck; 2) giant size; 3) involvement with critical perforating or branch vessels. Techniques of flow redirection, however, may offer an alternative treatment strategy for these difficult lesions. In this paper, we report on the use of this alternative strategy in the successful treatment of a left giant fusiform carotid terminus-M1 aneurysm in a 16 year-old boy suffering from Ehler-Danlos disease. This patient was admitted to our Institution because his aneurysm was continuing to be increasing in size, despite a previous ligation of his left cervical ICA which was performed at another institution 2 years earlier after the patient had experienced a hemorrhagic stroke. Upon admission, a neurological examination revealed a slight motor aphasia with mild right hemiparesis, remnant of the ancient stroke. Because of its size and the involvement with M1 perforating arteries, a direct aneurysm attack was deemed inadvisable. After an initial ECA-ICA high flow bypass which spontaneously thrombosed, we performed a repeated high flow bypass with the application of a single clip on M1, right distal to the fusiform dilatation. After an uneventful postoperative course, we were unable to observe any new neurological deficits after surgery. A CT scan on postoperative day 1 revealed that the aneurysm had undergone a spontaneous thrombosis which was completely obliterated at the time of a 6-month follow-up angiogram. At that time, the ECA-ICA bypass was found to be patent. In conclusion the alternative of flow alteration strategies can be successfully used in the treatment of aneurysms that cannot be safely trapped or occluded by traditional neurosurgical methods.

Spontaneous low cerebrospinal pressure: a mini review

Spontaneous intracranial hypotension (SIH) is a syndrome of low cerebrospinal fluid (CSF) pressure characterised by postural headaches in patients without any history of dural puncture or penetrating trauma. Described by Schaltenbrand in 1938, SIH is thought to result from an occult CSF leak resulting in decreased CSF volume and, consequently, in low CSF pressure. Magnetic resonance imaging of the head and spine has improved the diagnosis of the syndrome showing peculiar radiographic abnormalities including diffuse pachymeningeal enhancement, subdural fluid collections and downward displacement of the cerebral structures. Treatment of SIH headache should start with conservative, non-invasive therapies while epidural blood patch has emerged as the treatment of choice for those symptomatic patients who have failed medical noninvasive approaches.

Headache and intracranial hypotension: neuroradiological findings

The cardinal and classic features of postural headache and low cerebrospinal fluid (CSF) pressure in intracranial hypotension may not dominate the clinical picture of the syndrome and may be associated with additional various neurological symptoms and signs. Reports of unusual clinical presentations continue to appear in the literature. Despite the considerable variability of the clinical spectrum, neuroradiological studies reveal more constant and characteristic features. Brain MRI findings include intracranial pachymeningeal thickening and post-contrast enhancement, subdural fluid collections and downward displacement or "sagging" of the brain. Spinal MRI findings include collapse of the dural sac with a festooned appearance, intense epidural enhancement owing to dilatation of the epidural venous plexus, and possible epidural fluid collections. In fact, spinal studies may demonstrate CSF leakage from spinal dural defects, which are considered the most common cause of the syndrome. Myelo-MR may suggest the possible point of CSF leakage, by demonstrating an irregular root sleeve; myelo-CT and radioisotope myelocisternography (RMC) are often needed to confirm the point of CSF leakage. Neuroimaging studies are, therefore, essential for suggesting and confirming the diagnosis.

Hyperhomocysteinemia and other thrombophilic risk factors in 26 patients with cerebral venous thrombosis

Despite the continuous description of new conditions pre-disposing for cerebral venous thrombosis (CVT), no apparent cause is found in about 30% of cases. Hyperhomocysteinemia (hyper-Hcy) is an established risk factor for deep venous thrombosis and stroke but has not been clearly associated with increased risk of CVT. We assessed the prevalence of hyper-Hcy and other thrombophilic risk factors in a population of 26 consecutive patients with non-pyogenic CVT, by review of a prospectively maintained database. The prevalences of hyper-Hcy and prothrombin G20210A, factor V G1691A and methylenetetrahydrofolate reductase (MTHFR) C677T mutations in these patients were compared with those in 100 healthy controls and 100 patients with cerebroarterial disease. The prevalence of hyper-Hcy was greater in patients with CVT (10/26, 38.5%) than healthy controls (13/100; OR 4.18, 95% CI 1.58-11.16) and comparable with that in patients with cerebroarterial disease (42/100). No significant differences were found in the prevalences of prothrombin or MTHFR mutation. No factor V mutation was found. Our findings indicate that hyper-Hcy is associated with an increased risk of CVT. Additional prospective cohort studies on large series of patients are required to clarify the time relationship between hyper-Hcy and the thrombotic event.

Development and rupture of a de novo basilar artery aneurysm after surgical removal of a cerebellar arteriovenous malformation

BACKGROUND

The de novo development of an aneurysm in an previously normal artery is an uncommon event. We describe a patient who developed a de novo bleeding aneurysm of the basilar artery in the three weeks following the surgical removal of a large cerebellar AVM. METHOD-FINDINGS: A 48-year-old man suddenly developed transient headache, vertigo and disturbance of balance. Neuroradiological examinations showed the presence of a large AVM of the right cerebellar hemisphere. The AVM was removed successfully; following the operation there were repeated bleeding episodes at the operating site, requiring surgical evacuation. Three weeks after the AVM removal he suffered from a massive subarachnoid haemorrhage due to the rupture of an aneurysm developed de novo in the basilar artery.

INTERPRETATION

This is the first reported case, to our knowledge, of a de novo aneurysm developed in an artery hemodynamically related to a surgically removed AVM. This complication was probably due to the postoperative hemodynamic changes in the vessels afferent to the AVM, associated with arterial wall dysplasia.

Diagnostic imaging in 13 cases of Rasmussen's encephalitis: can early MRI suggest the diagnosis?

Rasmussen's encephalitis (RE) is a rare, progressive, chronic encephalitis characterised by drug-resistant epilepsy, progressive hemiparesis and mental impairment. It typically involves only one cerebral hemisphere, which becomes atrophic. We present neuroradiological findings in 13 children with RE. MRI was performed in all patients, fluorodeoxyglucose positron-emission tomography (PET) in three, Tc-99m hexamethylpropylenamine oxime single-photon emission computed tomography (SPECT) in two and proton MR spectroscopy ((1)HMRS) in two. MRI showed progression of the hemisphere atrophy, always prevalent in the region primarily involved (13 patients), spread of the abnormal signal in white matter (11) and cortex (10) and progression of atrophy of the head of the caudate nucleus (nine). Associated secondary changes were: atrophy of the contralateral cerebellar hemisphere (in four patients), the ipsilateral hippocampus (in five) and the brain stem (in five). The earliest CT and MRI abnormalities, seen between 1 day and 4 months after the first seizure (in 12 patients examined, nine of whom had MRI) in one cerebral hemisphere included: high signal on T2-weighted images in the cortex (seven patients) and white matter (nine), cortical atrophy usually involving the frontoinsular region, with mild or severe enlargement of the lateral ventricle (eight) and moderate atrophy of the head of the caudate nucleus (seven). Cortical swelling in the early stage of the disease was recognisable only in two patients. PET revealed hypometabolism, SPECT decreased perfusion, and (1)HMRS reduction of N-acetylaspartate in the affected hemisphere. PET and SPECT were usually performed in the late stages and did not provide specific findings. MRI thus demonstrates the progression of RE and may suggest the diagnosis in the early stages, often before the appearance of neurological deficits. Early diagnosis of RE may be crucial for selecting patients for aggressive medical therapy or major surgical interventions such as hemispherectomy.

Pigment villonodular synovitis of the spine. Case report and review of the literature

Pigmented villonodular synovitis (PVNS) is a disease of the joints which uncommonly involves the spine. We present a 70-year-old woman with radicular symptoms who was found to have a mass arising from a lumbar zygapophyseal joint with extension into the spinal canal. Following gross-total excision of the mass, histology revealed PVNS. One month after surgery, the patient had no symptoms and there was no evidence of residual or recurrent disease.

Congenital muscular dystrophy with merosin deficiency: MRI findings in five patients

We present the MRI findings in five patients with congenital muscular dystrophy (CMD) and merosin (laminin alpha2) deficiency, which was total in one and partial in four. In one patient with partial merosin deficiency, MRI was normal. The other four patients had supratentorial white matter abnormalities. In three, T2-weighted images revealed subcortical, deep lobar and periventricular high signal in white matter, while in the other there were only small peritrigonal areas of increased signal. On T1-weighted images, there was slightly low signal. Cortical abnormalities were absent. None of these changes were accompanied by symptoms or signs of central nervous system involvement. White matter abnormalities in a patient with CMD should prompt investigation of merosin.

Mitochondrial disease associated with the T8993G mutation of the mitochondrial ATPase 6 gene: a clinical, biochemical, and molecular study in six families

AIM

To contribute to the establishment of a rational clinical, neuroradiological, and molecular approach to neurogenic muscle weakness, ataxia, and retinitis pigmentosa (NARP) and maternally inherited Leigh's syndrome (MILS).

METHODS AND RESULTS

The T8993G mutation in the mitochondrial genome was found in several maternal members of six pedigrees, whose clinical status ranged from no symptoms to severe infantile subacute necrotising encephalomyelopathy (Leigh's disease). In one case a MELAS-like syndrome was documented both clinically and neuroradiologically. Relevant genetic features of the series were anticipation of symptoms through subsequent generations, and the presence of several cases in whom the mutation apparently occurred recently or was new. A uniform distribution of the mutation in many tissues was shown in one patient subjected to necropsy. In general, a good correlation was found between clinical severity and mutation heteroplasmy in readily accessible tissues, such as lymphocytes or fibroblasts. By contrast, a consistent reduction of the mitochondrial ATPase activity, to about half of the normal values, was found in most of the clinically affected cases, irrespective of the amount of mutant mitochondrial DNA.

CONCLUSIONS

Although the measurement of ATP hydrolysis in cultured fibroblasts was a reliable, and sometimes instrumental, means to identify T8993G positive patients, the relation between the mutation and the oxidative phosphorylation defect is probably very complex, and its understanding requires more complex biochemical analysis.

Lesionectomy in epileptogenic temporal lobe lesions: preoperative seizure course and postoperative outcome

A series of 54 patients operated on for temporal epileptogenic lesions is reported: 36 had slow growing tumours, 18 supratentorial cavernous angiomas. The patients were divided into two different groups according to the presence of seizures controlled (group 1) or not controlled (group 2) by antiepileptic drugs (AEDs). All the patients underwent preoperative scalp EEG and magnetic resonance imaging (MRI). They were operated on by pure lesionectomy, associated with amygdalo-hippocampectomy in 8 cases of uncontrolled seizures. Postoperatively they underwent MRI examination which revealed an incomplete lesionectomy in 12 cases. Patients were followed up after surgery for at least 2 years, 6 of them were reoperated on for the persistence (or regrowth) of the tumour. The results of epilepsy outcome are reported. These cases underline the importance of preoperative electroclinical study, in order to determine the relationship between lesion location and epileptic focus. If good concordance is present, a complete lesionectomy is enough to cure the patient. In other cases associated amygdalo-hippocampectomy leads to better results, while more complicated cases may need preoperative stereo-EEG studies.

Riboflavin-responsive glutaric aciduria type II presenting as a leukodystrophy

The clinical phenotype of multiple acyl-CoA dehydrogenase deficiency in infancy is characterized by recurrent episodes of hypoketotic hypoglycemia and lipid storage myopathy. Brain damage has been described only as a consequence of severe and protracted hypoglycemia. We describe a child who experienced normal physical and psychomotor development until the age of 3 years, who then developed progressive intention tremors, dysarthria, ataxia, and spastic tetraparesis. Episodes of acute metabolic distress were never observed. Magnetic resonance imaging disclosed abnormal signals within the white matter of the brain and cerebellum, suggesting leukodystrophy. Gas chromatography/mass spectrometry analysis revealed abnormally high levels of glutaric acid, dicarboxylic acids, and glycine derivatives in urine. Riboflavin therapy was initiated at 4 years of age, when the patient had already lost control of trunk and head posture. Consistent improvement rapidly occurred after riboflavin supplementation. Glutaric aciduria type II may cause brain damage, in spite of the absence of acute metabolic distress, and should be considered in the differential diagnosis of leukodystrophies.

Magnetic resonance imaging in progressive supranuclear palsy and other parkinsonian disorders

High field intensity MRI may demonstrate signal abnormalities consistent with deposits of iron or other paramagnetic substances in several extrapyramidal disorders. Hallervorden-Spatz disease was the only disorder widely known to have iron deposits in the pallidum, that are now easily demonstrated in vivo by MRI. However, lower field intensity MRI may also demonstrate characteristic findings. In progressive supranuclear palsy, definite atrophy of the midbrain and of the region around the third ventricle is seen in slightly more than half of the cases. Minimal signal abnormalities are sometimes seen in the periaqueductal region, but MRI studies remain of little help in establishing the diagnosis of the disease. Asymmetric atrophy in the parietal regions is seen in corticobasal degeneration, as expected from pathological studies. Minimal alterations may be seen in the substantia nigra in Parkinson's disease. The most interesting MRI findings are observed in multiple system atrophies. Variable abnormal signal intensities, depending on the field intensity, are visible in the putamen in striatonigral degeneration and in Shy-Drager syndrome; in this latter condition the abnormalities are due to its striatonigral degeneration component. Atrophy of the pons, middle cerebellar peduncles, and cerebellum, and signal abnormalities in a characteristic distribution are visible in olivopontocerebellar atrophy. A combination of these posterior fossa abnormalities and putaminal alterations may confirm the involvement of the cerebellar and extrapyramidal systems in multiple system atrophies.

Neurogenic arthrogryposis multiplex congenita: clinical and MRI findings

A clinical and magnetic resonance imaging (MRI) study on a selected group of 11 children, with a diagnosis of neurogenic arthrogryposis multiplex congenita (AMC) based on clinical, electromyographic, and muscle biopsy findings, is presented to determine the extent of central nervous system involvement in AMC. Family history, pregnancy, perinatal problems, other abnormalities, and epileptic seizures were reviewed. Neurologic examination, electroencephalography, intellectual assessment, and MRI study both of spinal cord and brain were performed. The clinical and laboratory findings disclosed evidence of spinal cord lesions with involvement of anterior horn cell function in all patients, and impairment of cerebral function in 5 patients. MRI revealed spinal cord atrophy in 3 patients, diffuse atrophy in 2 patients, and involved thoraco-lumbar segments in 1 patient. Cranial MRI studies demonstrated features of developmental brain abnormalities in 3 patients, cortical frontal atrophy in 2, and was normal in 4. In neurogenic AMC patients, MRI examination of the spinal cord and brain may help to clarify the pathogenesis of the disease and is helpful for prognostic and therapeutic purposes.

Calcium channel autoantibodies in myasthenic syndrome and small cell lung cancer

Lambert-Eaton myasthenic syndrome (LEMS) is one of the neurologic paraneoplastic syndromes often found in patients with lung cancer. It is characterized by a generalized deficit of neurotransmitter release. Patients with small cell lung cancer (SCLC) in particular may develop LEMS, and SCLC is very often detected in patients affected by LEMS. LEMS is an autoimmune disease, and autoantibodies that interfere with neurotransmitter release by binding to presynaptic voltage-operated calcium channels (VOCCs) have been found in sera of patients with LEMS. Both human neuronal and SCLC cell lines express omega-conotoxin-sensitive VOCCs, and autoantibodies from patients affected by LEMS can precipitate these channels. We have now screened a large population of patients and control subjects in order to define the specificity and sensitivity of the anti-VOCC antibody assay. We have tested sera from 52 patients with LEMS with and without SCLC; 32 sera from patients with SCLC without LEMS, 31 from patients with non-SCLC, 34 from patients with inflammatory lung diseases, 17 from patients with other neurologic disorders, and 48 from healthy control subjects. We have found that a positive result with this radioimmunoassay is highly specific for LEMS, with or without SCLC, when the antibody titer is higher than 14.21 pM. Anti-VOCC antibodies have also been found in about 40% of patients with SCLC without LEMS, but they were absent in all the other populations tested. We can conclude that this serologic assay is a very useful aid in the diagnosis of LEMS, and it might be useful also for the early diagnosis of SCLC.

Sex differences in spatial memory: a reanalysis of block tapping long-term memory according to the short-term memory level

This paper analyzes the spatial memory performance of 495 subjects. Both short-term and long-term memory have been analyzed by means of the Corsi block-tapping test. We provide separate norms for the learning of a supra-span sequence according to the level of spatial short-term memory. The long-term memory of males and females was compared in groups matched for spatial short-term memory, and the gender effect was never found to be significant. This finding is discussed in relation to the nature of sex differences in spatial abilities.