Treatment of Malignant Gliomas: A New Approach

The aim of this study is to describe the authors’ experience with intra-arterial ACNU chemotherapy of malignant gliomas. The prognosis of cerebral malignant gliomas remains poor, whatever traditional therapy is applied. ACNU is a well tolerated nitrosourea with a strong antimitotic effect on neurogenic cells both in vitro and in vivo; this drug has enhanced efficacy when used at high concentrations, particularly as an intraarterial infusion. Seventy-six patients have been studied to date, 68 of whom are evaluable; these patients were treated by intraarterial infusion of ACNU (100 mg/m2) every 6 weeks, with a mean of 2.5 courses per patient. The objective response (OR) was 28% and analysis of pretreatment factors revealed that survival was influenced by histological grade, other types of therapy applied, and age. In general IAC is well tolerated and the response and survival appear to be better than with systemic chemotherapy.

Idrocefalo comunicante in portatori di processi espansivi midollari

Si Segnalano due casi di idrocefalo tetraventricolare comunicante in cui la estensione delle indagini al rachide ha consentito di evidenziare due processi espansivi intramidollari oligosintomatici. Vengono riassunte le principali teorie fisiopatologiche finora formulate per interpretare la genesi dell'idrocefalo e suggerire alcune riflessioni di ordine diagnostico-terapeutico.

Stenosi carotidea: Confronto tra angio-RM e angio-TC spirale

A preliminary study comparing three dimensional time of flight (TOF 3D) Magnetic Resonance angiography (MRA) and spiral CT angiography (SCTA) in the detection and evaluation of internal carotid stenosis.

Digital subtraction angiography (DSA) was the gold standard.

Twenty patients with clinical signs of cerebrovascular insufficiency underwent MRA, SCTA and DSA within a three day period. Both internal carotid arteries were evaluated for absence or degree of stenosis.

Sensitivity, specificity, diagnostic accuracy, concordance, overstimation and understimation were assessed. MRA showed a higher sensitivity, specificity, diagnostic accuracy and concordance compared to SCTA (92% versus 80%, 98,2% versus 96,4%, 96,3% versus 88%, respectively). MRA demonstrated a 5% overstimation rate whereas SCTA demonstrated a 7,5% understimation rate. These differences are not statistically significant.

These results suggest that MRA is the more useful, non invasive modality for the detection and evaluation of the internal carotid artery with a greater than 70% stenoses.

Turbo-FLAIR Sequence in Brain MRI

To compare a turbo-FLAIR sequence with Proton Density (PD) and T2-weighted Turbo Spin-Echo (TSE) sequences in several different brain diseases, 276 MRI examinations were performed on a 1.0 Tesla system.

The positive cases were assessed for lesion detection and lesion conspicuity. Four quantitative criteria were also used to compare the contrast of the two techniques: lesion to background contrast, lesion to background contrast to noise ratio (CNR), lesion to Cerobrospinal fluid (CSF) contrast, lesion to CSF contrast to noise ratio.

The turbo FLAIR sequence was found to be superior to PD and T2-weighted TSE for lesion detection: this sequence detected more lesions in 74 patients than PD and in 42 patients than T2, but missed some subtentorial lesions. For lesion conspicuity turbo-FLAIR was judged equivalent to PD and T2-weighted TSE respectively in 27% and 45% of the cases and better in 71% and 53% of the cases. Lesion to background contrast and lesion to background CNR were found to be significantly greater for turbo-FLAIR than for PD (p<0.001). Compared with T2-weighted TSE, turbo-FLAIR showed a significantly higher lesion to background contrast (p<0.001) and inferior lesion to background CNR (p<0.001).

Our study indicates that turbo-FLAIR can replace PD TSE scans in most cases and can be used as a first choice sequence for cerebrovascular diseases, multiple sclerosis and for the evaluation of gliosis.

La nucleoaspirazione secondo Onik nel trattamento dell'ernia discale lombare analisi multicentrica dei primi risultati su oltre 650 trattamenti

Gli autori espongono i risultati ottenuti applicando la nucleotomia percutanea secondo Onik al trattamento dell'ernia discale lombare. Le casistiche sommate complessivamente ammontano a oltre 600 pazienti. Nel complesso i risultati sono buoni o ottimi nel 72% circa dei casi. I risultati insoddisfacenti, considerando globalmente i modest e gli invariati, corrispondonoal 26% circa. Eccezionali le complicanze (meno dell' 1 %): 1 discite (risolta con intervento chirurgico). La metodica di Onik può già essere serenamente considerata una possibilitanon trascurabile nel campo vasto e variegato dei trattamentidisponibili per l'ernia discale lombare

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.

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.

Phenylketonuria: white-matter changes assessed by 3.0-T magnetic resonance (MR) imaging, MR spectroscopy and MR diffusion

PURPOSE

This study evaluated the sensitivity of a 3.0-Tesla (T) magnetic resonance imaging (MRI) in measuring cerebral phenylalanine using proton magnetic resonance spectroscopy and in assessing MR-documented white-matter changes by means of diffusion studies (diffusion-weighted imaging, apparent diffusion coefficient map; diffusion tensor imaging) in patients with phenylketonuria.

MATERIALS AND METHODS

Thirty-two patients with the classical clinical and biochemical deficits of phenylketonuria underwent biochemical (blood phenylalanine), genotypic (phenylalanine hydroxylase gene) and radiological investigation by means of MRI, proton magnetic resonance spectroscopy and diffusion magnetic resonance imaging with a 3.0-T scanner.

RESULTS

Periventricular and subcortical white-matter changes were detected on all MR scans. In 29/32 patients, proton magnetic resonance spectroscopy easily documented abnormal signal elevation at 7.36 ppm, corresponding to phenylalanine, despite its low concentration. Phenylalanine signal amplitude relative to the creatine/phosphocreatine signal increased linearly with blood phenylalanine values (r 0.7067; p<0.001). Diffusion MRI demonstrated hyperintensity in the areas exhibiting MRI changes as well as decreased apparent diffusion coefficient values, but fractional anisotropy indices were normal.

CONCLUSIONS

The high signal, together with better spectral, spatial, contrast and temporal resolution, makes the 3.0-T MR the most suitable technique in the study of the phenylketonuria. In particular, the multimodal approach with MRI, proton magnetic resonance spectroscopy and diffusion magnetic resonance imaging can provide more information than previous studies performed with low-field systems.

3.0-T morphological and angiographic brain imaging: a 5-years experience

Ever since the introduction of magnetic resonance (MR), imaging with 1.5 Tesla (T) has been considered the gold standard for the study of all areas of the body. Until not long ago, higher-field MR equipment was exclusively employed for research, not for clinical use. More recently, the introduction of 3.0-T MR machines for new and more sophisticated clinical applications has resulted in important benefits, especially in neuroradiology. Indeed, their high gradient power and field intensity (3.0 T) allow adjunctive and more advanced diagnostic methodologies to be performed with excellent resolution in a fraction of the acquisition time required with earlier machines. The purpose of this paper is to illustrate the distinctive semeiological characteristics of 3.0-T morphological and angiographic brain imaging compared with lower-field systems and highlight the respective advantages and drawbacks based on the experience gained in the first 5 years from the installation of a 3.0-T magnet.

3.0-T functional brain imaging: a 5-year experience

The aim of this paper is to illustrate the technical, methodological and diagnostic features of functional imaging (comprising spectroscopy, diffusion, perfusion and cortical activation techniques) and its principal neuroradiological applications on the basis of the experience gained by the authors in the 5 years since the installation of a high-field magnetic resonance (MR) magnet. These MR techniques are particularly effective at 3.0 Tesla (T) owing to their high signal, resolution and sensitivity, reduced scanning times and overall improved diagnostic ability. In particular, the high-field strength enhances spectroscopic analysis due to a greater signal-to-noise ratio (SNR) and improved spectral, space and time resolution, resulting in the ability to obtain high-resolution spectroscopic studies not only of the more common metabolites, but also--and especially--of those which, due to their smaller concentrations, are difficult to detect using 1.5-T systems. All of these advantages can be obtained with reduced acquisition times. In diffusion studies, the high-field strength results in greater SNR, because 3.0-T magnets enable increased spatial resolution, which enhances accuracy. They also allow exploration in greater detail of more complex phenomena (such as diffusion tensor and tractography), which are not clearly depicted on 1.5-T systems. The most common perfusion study (with intravenous injection of a contrast agent) benefits from the greater SNR and higher magnetic susceptibility by achieving dramatically improved signal changes, and thus greater reliability, using smaller doses of contrast agent. Functional MR imaging (fMRI) is without doubt the modality in which high-field strength has had the greatest impact. Images acquired with the blood-oxygen-level-dependent (BOLD) technique benefit from the greater SNR afforded by 3.0-T magnets and from their stronger magnetic susceptibility effects, providing higher signal and spatial resolution. This enhances reliability of the localisation of brain functions, making it possible to map additional areas, even in the millimetre and submillimetre scale. The data presented and results obtained to date show that 3.0-T morphofunctional imaging can become the standard for high-resolution investigation of brain disease.

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.

The importance of suspecting superficial siderosis of the central nervous system in clinical practice

Once the central nervous system surface is greatly encrusted with haemosiderin, even removing the source of bleeding will have little effect on the progression of clinical deterioration. Superficial siderosis of the central nervous system is rare and insidious, but magnetic resonance imaging has turned a previously late, mainly autoptical diagnosis into an easy, specific, in vivo, and possibly early one. Avoiding long diagnostic delay will be very important in those cases susceptible of causal treatment.

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.

Magnetic Resonance applications in dental implantology: technical notes and preliminary results

PURPOSE

To evaluate the possible use of Magnetic Resonance Imaging (MRI) in the field of dental implantology, for identifying the mandibular nerve, as proposed by several authors.

MATERIALS AND METHODS

MRI was used for the study of the mandible in ten subjects (five healthy volunteers and five subjects awaiting dental implants). Imaging was performed on a 1.0-T MR scanner with a brain coil. T2 TSE, T1 spin-echo and T2 gradient-echo sequences were performed, both parallel and perpendicular to the horizontal portion of the mandible, with a thickness of 3 mm.

RESULTS

In all the subjects MRI clearly identified the intraosseous course of the inferior alveolar neurovascular bundle within the mandibular canal.

CONCLUSIONS

MRI appears useful for the depiction of the mandibular canal before dental implantation. Further studies are required to compare the accuracy of MRI and CT based on a statistically significant sample.

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.

Spinal epidural en-plaque meningioma with an unusual pattern of calcification in a 14-year-old girl: case report and review of the literature

A 14-year-old girl who presented with a severe sensory-motor-sphincter syndrome was found to be harboring an epidural tumor situated posteriorly in the spinal canal from C5 through C7 levels. The mass had computerized tomography and magnetic resonance imaging features suggesting an unusual stratified architecture, with a conspicuous highly calcific component firmly adherent to the dura and a non-calcific mass surrounding it posteriorly and laterally. Although meningiomas have a low incidence in the first two decades of life, and in the spine they rarely have entirely extradural location at any age, a meningioma was suspected. Intraoperative biopsy confirmed the tumor to be benign, and careful total resection including the whole large dural implant was carried out; the wide dural defect was grafted with fascia lata. A meningothelial meningioma with a largely calcified psammomatous component was diagnosed. The girl made a complete recovery, and is tumor-free 9 years postoperatively. Outcome from surgery for spinal meningiomas can be good, despite the severity of the preoperative condition; however, enplaque and highly calcific tumors still bear a poorer prognosis. Complete resection is mandatory in children, in whom they are extremely rare. Modern imaging techniques help in making a correct initial diagnosis and optimizing surgery in order to provide good results, even in more-challenging cases.

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.

Acute posttraumatic paraplegia caused by epidural hematoma at the vertex

Vertex epidural hematomas (VEDHs) are well known but uncommon. Their clinical presentation may be misleading and missed by routine CT axial scanning; thus, diagnosis may be delayed, with possibly fatal consequences. We report a case of acute posttraumatic paraplegia caused by a VEDH, which was evident at CT and for which the patient underwent successful surgery.

Spontaneous intracranial hypotension: the value of brain measurements in diagnosis by MRI

Caudal brain displacement is inconstantly reported as an MRI feature of spontaneous intracranial hypotension (SIH). We reviewed the clinical data and MRI of eight patients diagnosed as having SIH and investigated the possibility of more precise assessment. On midsagittal images we measured four anatomical landmarks: the position of the cerebellar tonsils, fourth ventricle, and infundibular recess, plus the angle between the bicommissural line and a line tangential to the floor of the fourth ventricle; midsagittal images from 89 normal controls were also measured. On statistical analysis, all measurements differed in the two groups, and the difference was significant for the cerebellar tonsils, fourth ventricle, and infundibular recess. Some overlap between patients and controls was found for each measurement; however, all the patients had two (two patients) or more (six) values outside the range in normal controls range or not above their 1st quartile. Measurement of the position of the third ventricle seemed particularly sensitive. We suggest that examination of midsagittal images can help in diagnosing clinically suspected SIH.

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.

Multicentric glioma with unusual clinical presentation

Multiple glioma is a well-recognized but uncommon entity. They are grouped in two categories: multifocal and multicentric gliomas. Multifocal gliomas grow through dissemination along an established route, spreading through commissural pathways, CSF channels, or the blood or by local extension through satellite formation; at the opposite end of the spectrum, multicentric gliomas are widely separated lesions whose simultaneous presence cannot be attributed to any of the above pathways. Reports in the literature refer to single cases or small series of multicentric gliomas, almost always in adult patients, their occurrence in children being even less frequent. We report the case of a 12-year-old boy with multicentric glioma, atypical acute clinical onset and fast growth of three other tumors in 8 months, and then discuss the problems of diagnosis and therapy.

Hippocampus and parahippocampal gyrus linear measurements based on magnetic resonance in Alzheimer's disease

MRI-based linear measurements of the hippocampus and parahippocampal gyrus complex (HPC) discriminated 39 subjects with probable Alzheimer's disease, from 15 patients with other dementias and 33 miscellaneous controls without evidence of dementia. The best discriminating parameter was the left height of the HPC at the level of the mammillary bodies, with a sensitivity of 79.49% and a specificity of 68.75%. The diagnostic value of these results is discussed considering the volumetric data found in the current literature.

MRI T-staging of laryngeal tumours: role of contrast medium

Our aim was to evaluate the relative diagnostic accuracy of MRI without contrast medium and MRI before and after contrast medium in the assessment of T-staging of laryngeal tumours. We studied 25 men (mean age 51.8, range 41-61) with laryngeal squamous cell carcinomas, using Spin-echo (SE) T1-weighted and fast SE T2-weighted sequences. The T1-weighted sequences were then repeated after gadolinium-diethylene-triaminepenta-acetic acid (Gd DTPA) 0.1 ml/kg. All patients then underwent biopsy and surgery. Two radiologists independently assessed the anonymised images by filling-out two multiple-choice forms, one for each technique, at a 2 week interval. The forms included a judgement concerning tumour identification and infiltration of the anterior commissure, supraglottic region, arytenoid cartilage, Morgagni's ventricle, paraglottic space, thyroid and cricoid cartilages, thyro-hyo-epiglottic space, vocal cords, subglottic region, and epiglottis. Similar forms were filled out by the surgeon and the pathologist after surgery. The sensitivity, specificity and diagnostic accuracy of MRI were unaffected by the use of contrast medium. Since it did not provide additional staging information, its continued routine use in these cases is not justified.

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.

Contrast-enhanced MR angiography (CE MRA) in the study of the carotid stenosis: comparison with digital subtraction angiography (DSA)

PURPOSE

To determine sensitivity, specificity and diagnostic accuracy of contrast-enhanced magnetic resonance angiography (CE MRA) compared to digital subtraction angiography (DSA) in the study of carotid stenosis.

METHODS AND MATERIAL

We studied 23 patients with suspected cerebro-vascular insufficiency by carotid stenosis. Diagnostic examinations by means of CE MRA and DSA were carried out within 24 hours of each other. A 1.5 T superconductive magnet (Signa-General Electric) was used for CE MRA. This technique was performed using a fast spoiled gradient echo recalled (SPGR) sequence acquired in coronal plane 13 sec after injection of contrast medium. Imaging parameters were: TR/TE/FA 8 msec/1 msec/60 degrees, matrix 256 x 128, 1 excitation, FOV 18 x 13 cm, 28 slices per slab, slice thickness of 1 mm, acquisition time of 32 sec. The post-processing was performed using maximum intensity projection (MIP) and targeted MIP. For DSA examinations a Politron 1000 VR unit (Siemens) was used.

RESULTS

In the identification and quantification of lesions, CE MRA showed values of 100%. In particular, in comparison to DSA, CE MRA was accurate in diagnosing all true negative and positive cases. The location of stenosis evaluated with CE MRA agreed in all cases with DSA.

CONCLUSION

In our experience CE MRA proved to be a very valuable technique in diagnosing carotid stenosis, showing the same diagnostic accuracy as DSA. In this way CE MRA appears to be a substantial alternative technique to conventional MRA and other non-invasive diagnostic methods.

Proton magnetic resonance spectroscopy of the brain in pediatric patients

H1-MRS is a non-invasive technique which provides different levels of information on brain tissue: the N-acetyl aspartate (NAA) is an indicator of neuronal development, the choline containing compound peak (Cho) provides information on myelination and on cell membrane turnover and gliosis, inositol (Ins) is considered a marker of neuronal degeneration. Lactate may be detected in presence of defective energy metabolism. In the perineonatal period, the brain is apt to be insulted by a variety of events including asphyxia, hypoxemia, hemorrhage, which may subsequently cause delay in development. It is clinically important to assess the degree of brain damage and to obtain the prognostic information in the neonatal and early infantile period. MRS has become available for clinical examinations of the brain during development and these techniques can be used to document improvement or the progression towards irreversible damage.

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.

High-resolution magnetic resonance angiography of the internal carotid artery: 2D vs 3D TOF in stenotic disease

The aim of this study was to compare high-resolution 2D TOF with high-resolution 3D TOF in the study of internal carotid artery disease. Sixty-four patients with clinical signs of cerebrovascular insufficiency were studied with a superconductive 1.5 T magnet using two techniques: 2D and 3D TOF. Digital subtraction angiography (DSA) was the gold standard. The 2D TOF technique was performed using the following parameters: TR/TE/FA/MA 49 ms/9 ms/60 degrees/512 x 256; the 3D TOF was performed with the following parameters: TR/TE/FA/MA 50 ms/8 ms/20 degrees/512 x 256. The 2D TOF agreed with DSA in 116 of 128 diagnostic judgments (90%) and overestimated seven times. The 3D TOF technique agreed with DSA in 125 of 128 diagnostic judgments (97%) with one overestimation and two underestimations. There was no statistically significant difference (P < 0.05) between the two different techniques. Our study confirms the high reliability of the methodology carried out with the high-resolution 2D and 3D technique.

MR angiography in carotid stenosis: a comparison of three techniques

PURPOSE

To compare the accuracy of three different magnetic resonance angiography (MRA) techniques for studying steno-occlusive disease of carotid arteries.

METHODS

64 patients were evaluated with three MRA techniques- three-dimensional (3D) time-of-flight (TOF), two-dimensional (2D) TOF, and 3D Phase-Contrast (PC); the acquisition was in the axial plane, the volume included the carotid bifurcation. Digital subtraction angiography (DSA) was considered the 'gold standard'. The MRA images were reprojected with a maximum intensity pixel ray-tracing (MIP) algorithm. The three MRA techniques were blindly graded as normal, mildly stenotic (0-29%), moderately stenotic (30-49%), severely stenotic (70-99%), or occluded.

RESULTS

DSA provided 128 diagnostic judgments: 92 were negatives and 36 positives. 2D TOF was in agreement with angiography in 116 of 128 cases (90%), but overestimated the results in seven cases and underestimated in five cases. 3D TOF agreed with angiography in 125 of 128 cases (97%), with one overestimation and two under estimations. 3D PC was concordant in 116 of 128 cases (90%), overestimating in six cases, underestimating in six cases. The sensitivity, specificity and diagnostic accuracy for 2D TOF was, respectively 84%, 94%, and 92%, while for 3D TOF was 94%, 100%, and 98%, and for 3D PC 86%, 98%, and 95%. The comparison of the three different MRA techniques provided no statistically significant difference (Friedman test P < 0.05).

CONCLUSION

The high degree of diagnostic accuracy of MRA found in the study of the steno-occlusive disease of the carotid arteries confirms the high degree of reliability of this methodology carried out with the 3D TOF technique, compared to 2D TOF and 3D PC.

Transcranial Doppler sonographic monitoring during cerebral aneurysm embolization: a preliminary report

BACKGROUND AND PURPOSE

The wide application of embolization in the treatment of aneurysms has created the need for an intraprocedural means to anticipate a poor outcome by monitoring hemodynamic changes in the brain.

METHODS

Transcranial Doppler sonography was used to monitor flow velocity in the middle cerebral artery (MCA) in 23 patients undergoing embolization with Guglielmi detachable coils (GDCs) of either incidental or symptomatic intracranial aneurysms. Sonographic values were recorded from the ipsilateral MCA at the beginning, middle, and end of the interventional procedure and 24 hours afterward.

RESULTS

No complications occurred in 15 patients. In these cases, sonography showed an average decrease in MCA flow velocity of 2.7% after GDC application, returning to baseline at the end of treatment and then increasing by about 17% 24 hours later. In four patients with vasospasm on posttreatment angiograms, MCA flow velocity increased to values higher than 120 cm/s after GDC application, returning to baseline after 24 hours. In four patients with ischemic complications (two transient ischemic attacks, one stroke, one vascular death), MCA flow velocity decreased more than 30% and did not return to preoperative values within 24 hours.

CONCLUSION

The application of transcranial Doppler sonographic monitoring during endovascular treatment may help to identify patients at risk for posttreatment cerebral ischemia.

Carotid stenosis: a comparison between MR and spiral CT angiography

We performed a preliminary study comparing three-dimensional time-of-flight (3 D TOF) magnetic resonance angiography (MRA) and spiral CT angiography (SCTA) in the detection and assessment of internal carotid artery stenosis. Digital subtraction angiography (DSA) was the reference examination. We examined 20 patients with signs of cerebrovascular insufficiency, who underwent MRA, SCTA and DSA within a 3 day period. Both internal carotid arteries were assessed by three blinded readers for degree of stenosis at two different levels (bulb and remaining section) giving a total of 80 assessments. Interobserver variability, sensitivity, specificity, diagnostic accuracy, concordance, overestimation and underestimation were assessed. Interobserver variability was not statistically significant. MRA showed higher sensitivity, specificity, diagnostic accuracy and concordance than SCTA (92.0% vs 80.8%, 98.2% vs 96.4%, 96.3% vs 91.3% and 96.0% vs 88.0%, respectively). MRA gave rise to a 5.0% overestimation rate, whereas SCTA occasioned a 7.5% underestimation rate. These differences are not statistically significant. These results suggest that MRA is a more useful, noninvasive modality for assessment of the internal carotid artery with a more than 70% stenosis.

Minor cerebral alterations observed by magnetic resonance imaging in syndromic children with mental retardation

OBJECTIVE

To evaluate the anomalies of the central nervous system (CNS) by magnetic resonance imaging (MRI) in normal subjects and in syndromic patients.

METHODS AND MATERIAL

Seventy-three normal subjects and 50 different syndromic patients with mental retardation (from 3 months to 16 years) were studied utilizing several morphometric parameters (degree of myelination of the white matter, evaluation of liquoral spaces, septo-caudate distance, Evans index, Aboulezz method, and length, width and angles of corpus callosum).

RESULTS

A high frequency of anomalies of the corpus callosum, the Chiari anomaly and alterations either of the white matter or of the ventricular and periencephalic system have been observed.

CONCLUSION

The authors point out the importance of cerebral MRI in the study of CNS in patients with malformation syndromes. The present research, carried out on a large number of both normal subjects and patients with malformation syndromes, represents one of the first systematic studies in this field.

[Stenosis-occlusion of the carotid bifurcation. Angiography with MR and contrast media versus digital angiography]

PURPOSE

To evaluate the comparative sensitivity, specificity and diagnostic accuracy of contrast enhanced magnetic resonance angiography (CE MRA) and digital subtraction angiography (DSA) in the study of carotid bifurcation stenoses.

MATERIAL AND METHODS

Twenty-three patients with suspected cerebrovascular insufficiency by carotid stenosis were examined with CE MRA and DSA within 24 hours of each other. A 1.5 superconductive unit (Signa, General Electric) was used for CE MRA; fast spoiled gradient echo recalled (SPGR) images were acquired on the coronal plane 12 s after contrast medium injection, with the following parameters: TR/TE/FA 8/1/60, MA 256 x 128, NEX 1, FOV 18 x 13, slices/slab 28, slice thickness 1 mm, TA 32 s. The images were postprocessed with the maximum intensity projection (MIP) and the targeted MIP algorithms. A Siemens Politron 1000 VR unit was used for DSA examinations.

RESULTS

DSA diagnosed 21 true positives, namely 4 grade II, 4 grade III, 10 grade IV and 3 grade V stenoses. CE MRA scored 100% in stenosis identification and grading, accurately diagnosing all the true negatives and the true positives and was always in agreement with DSA as to stenosis site.

CONCLUSION

CE MRA can be considered the technique of choice to study stenosis occlusion in the epiaortic vessels, because it permits a rapid panoramic study of the neck vessels and accurate stenosis grading with similar patterns to those of DSA. Thus, CE MRA appears to be a valid alternative to DSA.

[Magnetic resonance angiography of the vessels of the neck: the optimization of a dynamic technic during the rapid infusion of a paramagnetic contrast medium]

INTRODUCTION

A new noninvasive technique, dynamic Magnetic Resonance Angiography (MRA) during rapid infusion of paramagnetic contrast medium, has been recently developed for the study of neck vessels. This study was carried out to optimize technical parameters.

MATERIALS AND METHODS

Twenty healthy volunteers (10 men and 10 women; age range: 25 to 50 years) were examined with a 1.5 T MR unit equipped with fast imaging software and a dedicated coil. Dynamic MRA was performed using fast spoiled gradient recalled (fast SPGR) sequences acquired on the coronal plane 13 s after contrast medium injection. Imaging parameters were: Echo Time (TE): 1 ms, Repetition Time (TR): 8 ms, flip angle: 60 degrees, matrix 256 x 128, number of excitations: 1, field of view: 18 x 13 cm, number of partitions per slab: 28, slice thickness: 1 mm, acquisition time: 32 s. A dose of .2 mmol/kg of paramagnetic contrast medium was administered with an MR compatible automatic injector, at a speed rate of 1.5 ml/s. Angiographic images were postprocessed with the maximum intensity projection (MIP) and targeted MIP algorithms.

RESULTS

Using the above parameters and rapid contrast medium injection, the carotid arteries on the coronal plane (including the vessels from the proximal aspect of the common carotid arteries to the intracranial tract of the internal carotid arteries) in 18 cases. In the other two cases the tortuosity and the position of the carotid arteries on two different planes, prevented their complete visualization. The vertebral arteries were completely demonstrated in 50% of the investigated population. Partial or total overlapping of jugular veins did not affect the recognition of the carotid vessels in 10 cases, also with targeted MIP postprocessing.

DISCUSSION

The vascular semiology of dynamic gadolinium enhanced MRA seems to be closer to that of conventional angiography than of conventional MRA, likely due to the same modality of vessel depiction, based on contrast medium administration. Flow artifacts, the major pitfall of conventional MRA causing signal void and overestimation of stenosis grade, are not frequent in dynamic MRA.

CONCLUSIONS

Gadolinium enhanced dynamic MRA ensures panoramic and high resolution angiographic-like depiction of the neck vessels, providing rapid and excellent definition of vascular morphology. Thus dynamic MRA appears to be a substantial alternative to conventional MRA and conventional angiography.

[Whole-body magnetic resonance angiography using a contrast medium. Technical optimization]

INTRODUCTION

We tried to optimize the technique of contrast enhanced MR Angiography (MRA) in the study of the main body arteries.

MATERIALS AND METHODS

Fifty volunteers were examined with contrast enhanced MRA with a superconductive magnet at 1.5 T (Signa GE) and 3D SPGR sequences acquired with the following parameters: TR 8.2 +/- 1.3 ms, TE 1.8 +/- 7 ms, FA 60 degrees, MA 128 X 256; the images were acquired on the sagittal or coronal planes. The contrast agent (Gd-DTPA) was injected with MedRad Spectris system, with the bolus technique and the following standard parameters: velocity 1.5 mL/s and single dose; circulation time was optimized with 2D SPGR for each vessel (pretest). The carotid and pulmonary arteries, the thoracic-abdominal aorta and the iliac arteries were studied. The reader used a multiple choice card to evaluate image quality, signal-to-noise ratio (SNR) and circulation time.

RESULTS

Circulation time was 10.2 s in the carotid arteries, 8.1 s in the pulmonary arteries, 10.3 s in the thoracic aorta, 12.2 s in the abdominal aorta and 13.8 s in the iliac arteries. The signal was 181.8 vs the noise 3.1 in the carotid arteries, 256.8 vs 23.2 in the thoracic aorta, 518.4 vs 23.5 in the pulmonary arteries, 258.8 vs 24.5 in the abdominal aorta and finally 262.7 vs 25.4 in the iliac arteries.

CONCLUSIONS

Our experience suggests that contrast enhanced MRA is a good technique to study body arteries.

Spiral CT angiography in the study of the carotid stenoses

PURPOSE

To determine sensitivity, specificity and diagnostic accuracy of spiral CT angiography (S-CTA) compared to Digital Subtraction Angiography (DSA).

MATERIALS AND METHODS

We studied 40 patients with suspected cerebro-vascular insufficiency by carotid stenosis. Diagnostic examinations by means of S-CTA and DSA were carried out within 24 hours of each other. Twelve of these patients underwent thromboendoarterectomy (TEA). Prospeed SX GE was used for S-CTA. Post-processing was performed using Maximum Intensity Projection (MIP) after deleting osteo-muscular structures and CT angiograms were displayed in an oblique anterior view at an angle of 10 degrees-15 degrees along the longitudinal axis. For DSA examinations, a Siemens Politron 1000 VR unit was used.

RESULTS

In this study S-CTA showed values of sensitivity, specificity and diagnostic accuracy of 88%, 100% and 96%, respectively.

CONCLUSIONS

In the future, with the improvement of non-invasive techniques (S-CTA, MRA), DSA should be replaced, as the gold-standard, in the evaluation of stenotic disease of the carotid bifurcation.