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Resume Introduction L’intoxication au manganese a ete initialement decrite dans le cadre d’exposition professionnelle. Plusieurs observations d’intoxication exogene au manganese ont ete rapportees associant des symptomes neuropsychiatriques, un syndrome parkinsonien d’intensite variable et un hypersignal T1 bipallidal a l’IRM. Plus recemment, ont ete decrits des tableaux radiocliniques similaires sans exposition exogene au manganese mais dans le cadre d’intoxication endogene, notamment chez des patients atteints d’insuffisance hepatique chronique. Observation Nous rapportons le cas d’un homme, âge de 41 ans, coinfecte VIH-VHC avec cholestase, chez qui le diagnostic de neurotoxicite au manganese a ete evoque devant des signes peu specifiques (ralentissement psychomoteur) et la presence d’un hypersignal T1 bipallidal a l’IRM cerebrale, puis confirme par le dosage sanguin de manganese. A cette occasion, nous presentons une revue de la litterature sur les intoxications endogenes et exogenes au manganese et les diagnostics a evoquer devant un hypersignal T1 bipallidal. Conclusion La presence d’un hypersignal T1 bipallidal dans le cadre de symptomes neurologiques doit faire evoquer le diagnostic d’intoxication au manganese, meme en l’absence d’un syndrome parkinsonien.

Introduction Neoangiogenesis is a critical feature that can differentiate high-grade from low-grade glioma. Conventional MR imaging does not assess this histological feature accurately. The goal of this study was to evaluate the gain in relative cerebral blood volume measurement using perfusion MRI in the management of cerebral gliomas. Materials and methods Between 1998 and 2001, 32 histologically proven glial tumors were assessed by perfusion MRI using echoplanar imaging (EPI) and gradient-echo techniques. Relative cerebral blood volume (rCBV) was measured in all patients and compared to histological data. Results rCBV values were significantly correlated to histological grading in all 32 patients (P Conclusion Perfusion MRI using the EPI technique reliably assesses tumoral neoangiogenesis in gliomas preoperatively. The specificity and sensitivity of this technique make this radiological modality a valuable tool in the assessment of cerebral gliomas.

The localization of functional areas obtained from functional MRI (fMRI) is useful for patients suffering from tumors contiguous to eloquent brain areas. fRMI is an efficient tool in the strategy of treatment of low grade oligodendroglioamas in the rolandic area in intact or slightly impaired patients. It can be used preoperatively to assess motor functional areas. Indeed there is a good correlation for motor cortex lesions when using comparison between fMRI and intraoperative findings. Direct integration of fMRI data into neuronavigation enables to better visualize and preserve eloquent brain areas. One must be aware of fMRI limits. It is still often used with the control of direct cortical stimulations.

Resume Le radiodiagnostic dentaire represente plus de la moitie des actes radiologiques des pays developpes, mais une faible part de l'exposition aux rayons X en raison de la petite quantite de rayons X delivree par chaque acte. Le risque essentiel attribue a cette activite est l'induction de cancers a long terme car le risque teratogene et le risque genetique sont nuls eu egard a l'insignifiance des doses delivrees a l'uterus et aux organes genitaux. Pour le risque cancerogene associe a ces faibles doses de rayonnement, les donnees epidemiologiques ne sont pas probantes mais les instances internationales pronent un modele de calcul de risque extrapole des effets des fortes doses de rayonnement sous forme d'une relation lineaire sans seuil pour ne pas sous-estimer le risque. L'estimation et la mention sur le compte rendu de la dose delivree par tout examen radiologique sont dorenavant obligatoires et inscrites dans le Code de sante publique par la transposition de la directive Euratom 97/43. Les doses delivrees par les examens usuels du radiodiagnostic dentaire sont indiquees et les effets potentiels de ces doses mis en perspective. Le respect des principes de justification et d'optimisation permet de pratiquer le radiodiagnostic dentaire en toute serenite.

La Commission internationale de protection radiologique a mis l’ete dernier sur son site Internet, pour avis, son nouveau projet de recommandations avant de le finaliser courant 2005. Comme pour les ebauches precedentes, la Societe francaise de radioprotection a, au travers d'un groupe de travail, fait ses commentaires sur le projet actuel. Le texte envoye a la CIPR est presente ici aux lecteurs de la revue de la SFRP.

Resume Apres un rappel sur les outils de mesure de l'irradiation, sont abordes les parametres de l'irradiation en scanner helicoidal (monocoupe et multicoupe) : ce sont les parametres techniques (tension, charge du tube) et spatiaux (geometrie du faisceau, epaisseur de coupe, pitch). Leur influence sur l'irradiation est abordee puis leur modulation automatique ou manuelle afin d'optimiser le compromis dose/qualite d'image.

L'Association internationale de protection radiologique (IRPA) a invite, en 1999, les societes nationales a participer au debat sur l'evolution du systeme de protection radiologique propose par la CIPR. Repondant a cette invitation, le conseil d'administration de la Societe francaise de radioprotection (SFRP) a cree un groupe de travail specifique. Ce groupe s'est reuni d'avril 1999 a juillet 2000, et les resultats de ses travaux ont ete presentes lors du congres IRPA-10 en mai 2000. Pour continuer cette reflexion, le conseil d'administration de la SFRP a decide de creer un deuxieme GT qui a debute ses travaux en septembre 2001. Ce GT est compose d'une trentaine de membres representant les parties prenantes de la radioprotection en France : autorites, experts et professionnels des domaines nucleaire, medical et de la recherche, ainsi qu'une personne issue du mouvement associatif. L'objectif de ce GT est de formuler des propositions sur des questions cles qui pourraient etre abordees, en particulier par la CIPR, dans le developpement de nouvelles recommandations de radioprotection. Le choix des sujets prioritaires resulte de l'experience des membres du GT ainsi que de l'analyse des propositions de la CIPR. Cet article presente les principales conclusions du GT dans une formulation cherchant a refleter les diverses opinions qui ont pu etre exprimees lors des seances de travail.

The value of functional MR Imaging (fMRI) in assessing language lateralization in epileptic patients candidate for surgical treatment is increasingly recognized. However few data are available for left-handed patients. Moreover determining factors for atypical dominance in patients investigated with contemporary imaging have not been reported. We studied 20 patients (14 males, 6 females; 9 right handed, 11 left handed) aged from 9 to 48 years, investigated for intractable partial epilepsy. Epileptic focus location was temporal in 14 cases, extratemporal in 6, and lateralized in the left hemisphere in 11/20. Hemispheric dominance for language was evaluated by both Wada test and fMRI using a silent word generation paradigm in all patients. Furthermore, a postictal speech test was performed in 15 patients. An fMRI language lateralization index was calculated from the number of activated pixels (Student's t test, P < 0.0001) in the right and left hemispheres. The Wada test showed a right hemispheric dominance in 8 patients (6 were left handed and 2 right handed) and a left hemispheric dominance in 12 patients (5 were left handed and 7 right handed). These results were concordant with clinical postictal examination in 11/15 patients (73%). Clinical status did not allow a conclusion about hemispheric dominance for the remaining 4 patients. FMRI was concordant with the Wada test in 19/20 cases. For one left-handed patient, fMRI showed bilateral activation, whereas the Wada test demonstrated a right hemispheric dominance. Right language lateralization was significantly correlated with left lateralized epilepsy (P < 0.05) but was not correlated with age at epilepsy onset, early brain injury (before 6 years), and lobar localization of epileptogenic focus. However the lack of a significant relationship between these factors and atypical language lateralization may be related to the small sample size.

Avec les progres des appareils et des techniques d'imagerie, la presque totalite des personnels medicaux exposes aux rayonnements ionisants ne recoit plus aujourd'hui que des doses de rayonnement tres faibles, voire insignifiantes. Ces personnels ne repondent plus a la definition legale de personne directement affectee aux travaux sous rayonnements (categorie A), supposes pouvoir recevoir annuellement des doses a l'organisme entier comprises entre 6 et 20 mSv. Ces personnels doivent donc etre classes en categorie B et les salles ou ils travaillent doivent etre des zones surveillees et non des zones controlees. Seuls certains postes (angiographie et radiologie interventionnelle, injection de radiopharmaceutiques en medecine nucleaire) doivent rester classes en zones surveillees, avec classement en categorie A des personnels qui y sont affectes. Ce changement de classement permet une surveillance dosimetrique rationnelle, reservant la dosimetrie active, electronique (en sus de la dosimetrie passive) aux seuls personnels de categorie A, tandis que la majorite des personnels, categorie B, restent surveilles par des dosimetres passifs, a periodicite de lecture trimestrielle. Ce classement repose sur des etudes de postes individuelles prenant en compte l'exposition reelle du personnel lors de l'activite de la salle et calculant l'exposition maximale theorique qui pourrait etre atteinte par un travailleur affecte en permanence a cette salle.

The aim of functional brain magnetic resonance imaging studies is to determine which regions of the brain are related to a given specific task. Different methods can be used to extract the functional signal and there is currently no consensus for this operation. Measures based on correlation are only relevant for a single task. In this paper, we propose a method based on a multivariable Student's t test that permits the comparison of the results of successive activations. This technique allows a qualitative analysis of complex tasks, making possible to deal with both similar and different activated cortical areas.

Objective: Improvement of neurosurgical techniques with a more detailed description of brain tumors and their functional environment. Methods: We performed: (1) anatomical magnetic resonance imaging (MRI) for reference, (2) functional sequences dedicated to the adjacent cortical structures (sensorimotor, visual, language paradigms), and (3) thallium 201 cerebral tomoscintigraphy to visualize active tumor invasion. Data were transferred to a workstation for automatic registration. Results: All data were combined into one synthetic image showing the foci of high proliferative activity, which have to be completely resected, and the peritumoral functional structures, which have to be spared in order to minimize postoperative sequelae. This trimodal image is entered into a surgical neuronavigation computer for preoperative planning in order to outline tumoral target and functional risk areas. All this information is displayed in the operative microscope (Zeiss MKM) optically linked to MR images. This multimodality technique diminishes operative time by reducing electrocorticography and improves the operative short-term outcome. Conclusion: Multimodal imaging is useful for optimization of neurosurgical tumor resection.

Objective : To assess the value of high resolution 2D fast spin echo T2-weighted sequence (HR 2D-FSE T2w) for evaluating the internal auditory meatus (IAM) in patients with asymetric or unilateral sensorineural hearing loss, vs. gadolinium-enhanced T1-weighted (Tlw) sequence; to suggest a screening protocol to exclude the diagnosis of acoustic neuroma in a patient with isolated unilateral sensorineural hearing loss. Materials and methods: One-hundred ten patients with suspected acoustic neuroma were evaluated with 1.5 T MRI system. The protocol included axial images focused on the IAM: HR 2D-FSE T2w images (4000/63, ETL=16, 3-mm sections with 1.5 mm overlap, 18 FOV, 512 × 384 matrix) and gadolinium-enhanced Tlw images (600/23, 3-mm sections, 18 FOV, 256 × 192 matrix). Two criteria for normality of the HR 2D-FSE T2w examination are defined: high homogeneous signal of the cerebellospinal fluid (CSF) and linear low signal of the nerves visible throughout the IAM. Results: Overall results show no false-negative and six false-positive with HR 2D-FSE T2w sequences vs. gadolinium-enhanced Tlw sequences. The sensitivity of HR 2D-FSE T2w sequence is 100%, specificity 93%, and negative preditive value 100%: normal images using HR 2D-FSE T2w sequence can rule out the diagnosis of acoustic neuroma. Conclusion: Using this protocol we can exclude the diagnosis of acoustic neuroma in case of normal HR 2D-FSE images and no additional gadolinium-enhanced Tlw sequence is necessary. This protocol might reduce examination time, must promote recourse to MRI in the event of clinical suspicion of acoustic neuroma, and also enables savings by proposing MRI examination as a first-line exam.

A 74-year-old man, with well-controlled diabetes, presented with 3 months of progressive delirium. Examination revealed left homonymous upper quadrantanopsia. MRI demonstrated right temporal lesion and right lateral sinus thrombosis (figure). CSF examination revealed elevated protein level (1.31 g/L) without pleocytosis. Microbiology tests were negative, including HIV. …

Hypermanganism is primarily linked to inhalation exposure. Several observations of exogenous manganese poisoning have been reported associating neuropsychiatric symptoms, parkinsonian syndrome and hyperintensities of the two pallida on T1 weighted sequences on brain MRI. Recently, similar neurological and radiological signs have been described without exogenous exposure to manganese but in the framework of endogenous poisoning particularly in chronic hepatic failure.We report the case of a 41-year-old HIV-positive and HVC-positive man who presented psychomotor impairment associated with bipallidal T1 hyperintensities on the brain MRI. The diagnosis of a hypermanganesemia was made on blood samples. We present a literature review on exogenous and endogenous hypermanganesemia and discuss differential diagnosis in the radiological setting of bipallidal T1 hyperintensities.Bipallidal T1 hyperintensities on brain MRI may suggest hypermanganism even in the clinical setting of a non-specific neurological disorder such as psychomotor impairment.

Neoangiogenesis is a critical feature that can differentiate high-grade from low-grade glioma. Conventional MR imaging does not assess this histological feature accurately. The goal of this study was to evaluate the gain in relative cerebral blood volume measurement using perfusion MRI in the management of cerebral gliomas.Between 1998 and 2001, 32 histologically proven glial tumors were assessed by perfusion MRI using echoplanar imaging (EPI) and gradient-echo techniques. Relative cerebral blood volume (rCBV) was measured in all patients and compared to histological data.rCBV values were significantly correlated to histological grading in all 32 patients (P0.001). Mean rCBV values were 8.74 (+/-3.79) for glioblastomas, 7.37 (+/-2.83) for anaplastic gliomas and 0.84 (+/-0.61) for low-grade gliomas. Mean rCBV values were significantly different between low- and high-grade gliomas, making it possible to determine a threshold (2.5-3) that can separate these two types of lesion. In determining the histological grading, rCBV was shown to be significantly more accurate than conventional MRI (P0.005).Perfusion MRI using the EPI technique reliably assesses tumoral neoangiogenesis in gliomas preoperatively. The specificity and sensitivity of this technique make this radiological modality a valuable tool in the assessment of cerebral gliomas.

The localization of functional areas obtained from functional MRI (fMRI) is useful for patients suffering from tumors contiguous to eloquent brain areas. fRMI is an efficient tool in the strategy of treatment of low grade oligodendroglioamas in the rolandic area in intact or slightly impaired patients. It can be used preoperatively to assess motor functional areas. Indeed there is a good correlation for motor cortex lesions when using comparison between fMRI and intraoperative findings. Direct integration of fMRI data into neuronavigation enables to better visualize and preserve eloquent brain areas. One must be aware of fMRI limits. It is still often used with the control of direct cortical stimulations.

Exposure to ionizing radiation during pregnancy always is a worrisome event. Knowledge of teratogenic and carcinogenic mechanisms based on reliable scientific data (ICRP 84) allows appropriate management of patients following exposure to ionizing radiation. Radiation exposure in the setting of diagnostic imaging studies is not associated with an increased risk of fetal malformation; however, the risk of childhood malignancy is minimally increased. This information must be provided to parents so they may reach an informed decision with regards to the outcome of the pregnancy. The analysis of the quality and quantity of exposure should be limited to imaging examinations where the abdomen was exposed. Management will be based on the type of exposure. Guidelines are provided for various exposure situations and all radiologists must be able to manage such situations.

To compare low-dose protocols using either reduction of the tension (kV) or reduction of the intensity (mAs) at abdominal CT imaging, with reference to image quality.Fifty adult patients, weighing less than 55 kg, were prospectively included among patients referred for abdominal CT examination when the protocol required a noncontrast study. The images obtained with the standard protocol (120 kV, 200 mAs) were compared to 4 additional test images, two obtained with low intensity (120 kV, 100 mAs) and two obtained with low tension (100 kV, 200 mAs). Two senior radiologists blindly reviewed all images using both subjective (itemized list) and objective criteria (measure of standard deviation for density measurements obtained of the liver parenchyma).The image quality of the low kV protocol was better than the image quality of the low mAs protocol for both subjective and objective criteria.For abdominal CT imaging of standard to thin adult patients or children, dose reduction using a low kV protocol may be an alternative to a protocol using a low intensity. This can easily be implemented and can be used in conjunction with a dose reducing software.

Intradiploic meningoencephalocele is rarely found in adulthood. It is thought to be postraumatic and must be differenciated from congenital encephalocele. Imaging findings, particularly with Magnetic Resonance Imaging, are useful in determining the various linings and contents of this intradiploic defect.

Periventricular enhancement in adults at MRI is a significant finding since it often indicates the presence of an underlying disease requiring prompt medical attention. From a review of patients with periventricular enhancement, the main imaging features based on the underlying infectious or tumoral etiology will be described. The presented differential diagnosis is based on the immune status of the patient, type of enhancement, and response to a trial therapy. In immunocompromised patients, the main considerations are lymphoma and viral ependymitis. The pattern of enhancement is important. The presence of thin linear enhancement suggests a viral etiology (cytomegalovirus or varicella-zoster virus) that can be confirmed at CSF evaluation whereas the presence of nodular enhancement suggests a diagnosis of primary CNS lymphoma that can be confirmed by the presence of lymphomatous cells in the CSF or, more frequently, at stereotactic surgical biopsy performed after failure of response to anti-toxoplasmosis treatment. The presence of band enhancement is less specific and can be seen with viral, lymphomatous and even tuberculous involvement. In immunocompetent patients, a clinical context of infection will suggest bacterial or tuberculous ventriculitis and the presence of cystic lesions will suggest cysticercosis; in the absence of constitutional symptoms, the presence of nodular enhancement will suggest a tumoral process (lymphoma, ependymoma, germ cell tumor, or metastases). Rarely, linear enhancement will be due to sarcoidosis or Whipple's disease.

After reviewing the anatomical and functional aspects of the occipital lobe, the authors detail its gyral and sulcal anatomy using MRI in the three planes, with particular attention given to the localization of the calcarine fissure.

A more extensive description of brain disease for radiotherapy and neurosurgery treatment planning can be obtained by co-registering functional image sets, obtained from /sup 201/Tl-SPECT and/or fMRI, with corresponding anatomical image sets, obtained from MRI or CT. Using the external edge of the head, which is visible on both the functional and anatomical image sets, an automatic matching procedure based on the chamfer method allows multi plan fusion slices to be displayed and analyzed with a dedicated software package. Approximately one hour is required for matching, analysis, and data transfer. The co-register functional image set output files are written in a format compatible with local neurosurgery and radiotherapy applications. A multimodal application in a clinical environment requires a matching algorithm, knowledge of the data formats and dedicated visualization software. Co-registration and fusion of SPECT, fMRI and MR image sets was performed to optimize surgery and radiotherapy for 5 and 3 patients respectively. The influence on neurosurgery and stereotaxic irradiation will be evaluated by the patient follow up.

Implementation of EURATOM directive 97/43 requires increased scrutiny over the use CT imaging. All CT imaging centers will be required to perform routine QA procedures including measurements of exposure related to frequently performed types of CT examination. CT technologists and radiologists will be required to try and identify ways of decreasing patient exposure for CT examinations while insuring acquisition of diagnostic studies. In turn, this assumes understanding of the exposure parameters displayed on the CT images. Based on this, radiologists will be in a position to compare exposure parameters in their practice to national standards and perform necessary adjustments. Also, it should become possible to more adequately estimate patient exposure related to specific CT examinations.

Residual activation of the cortex was investigated in nine patients with complete spinal cord injury between T6 and L1 by functional magnetic resonance imaging (fMRI). Brain activations were recorded under four conditions: (1) a patient attempting to move his toes with flexion-extension, (2) a patient imagining the same movement, (3) passive proprio-somesthesic stimulation of the big toes without visual control, and (4) passive proprio-somesthesic stimulation of the big toes with visual control by the patient. Passive proprio-somesthesic stimulation of the toes generated activation posterior to the central sulcus in the three patients who also showed a somesthesic evoked potential response to somesthesic stimulation. When performed under visual control, activations were observed in two more patients. In all patients, activations were found in the cortical areas involved in motor control (i.e., primary sensorimotor cortex, premotor regions and supplementary motor area [SMA]) during attempts to move or mental imagery of these tasks. It is concluded that even several years after injury with some local cortical reorganization, activation of lower limb cortical networks can be generated either by the attempt to move, the mental evocation of the action, or the visual feedback of a passive proprio-somesthesic stimulation.

To evaluate residual activity in the sensorimotor cortex of the lower limbs in paraplegia.5 patients suffering from a complete paralysis after traumatic medullar lesion (ASIA=A). Clinical evaluation of motility and sensitivity. 1. Control functional MR study of the sensorimotor cortex during simultaneous movements of hands, imaginary motor task and passive hands stimulation. 2. Concerning the lower limbs, 3 fMRI conditions: 1-patient attempts to move his toes with flexion-extension, 2-mental imagery task of the same movement, 3-peripheral passive proprio-somesthesic stimulation (squeezing) of the big toes.Activations were observed in the primary sensorimotor cortex (M1), premotor regions and in the supplementary motor area (SMA) during movement and mental imaginary tasks in the control study and during attempt to move and mental imaginary tasks in the study concerning the lower limbs. Passive somesthesic stimulation generated activation posterior to the central sulcus for 2 patients.Activations in the sensorimotor cortex of the lower limbs can be generated either by attempting to move or mental evocation. In spite of a clinical evaluation of complete paraplegia, fMRI can show a persistence of sensitive anatomic conduction, confirmed by Somesthesic Evoked Potentials.

The purpose was to incorporate preoperative functional imaging data into anatomic data of operative microscope for neurosurgical procedures of patients suffering from lesions contiguous to eloquent brain areas. The day before surgery, patients bearing scalp markers underwent fMRI, just before anatomical contrast-enhanced MR images. FMRI data analysis were realised using a t test (p0.0001). The resulting functional-anatomical images were downloaded onto a surgical neuronavigation computer in order to outline tumoral target and functional areas. At surgery, cortical stimulation has been used to confirm functional data. Functional image-guided surgery of lesions abutting functional cortex can be safely performed.

Helical computed tomography is the main source of ionizing radiation delivery in diagnostic radiology. For each series, average radiation dose is between 20 and 30 mGy. This dose can potentially be reduced by decreasing intensity or voltage and by increasing pitch. Helical acquisition allows reformating of images with smaller increment or different obliquity, and avoids additional irradiation. Hardware and software devices designed for dose reduction must be systematically used. Users of CT systems should be aware of radiation dose delivered with CT and must carefully assess the need of each additional acquisition. Obsolete habits, as gantry tilting for lumbar CT, which increases patient exposure, must be given up. Rational use of helical CT decreases radiation exposure and gains time, whereas thoughtless use increases radiation exposure without real benefit.

Helical CT is the imaging modality that delivers the highest exposure to patients. For each acquisition, the average radiation dose is between 20 and 30 mGy. This dose can potentially be reduced by decreasing the intensity or voltage and by increasing the pitch. Helical data can be reformatted to obtain images with smaller increment or multiplanar reconstructions, hence reducing the need for additional acquisitions. Hardware and software devices designed for dose reduction must be systematically used. Operators of CT units should be aware of the radiation dose delivered with helical CT and must carefully assess the need of each additional acquisition. Obsolete protocols such as angulation of the gantry for lumbar CT, which increases patient exposure, should no longer be used. Rational use of helical CT decreases radiation exposure and is faster, whereas improper use increases radiation exposure without added benefit.

We report the case of a 25-year-old man who presented a fibrous pseudotumor of the epididymis, a rare focal location of nodular and diffuse fibrous proliferation. We provide the ultrasonographic and MRI findings with pathologic correlation.

Cerebellopontine angle tumors in adults are mainly benign and extra-axial. Magnetic resonance imaging is the first method for their diagnosis, CT being more useful for bony structures evaluation. Vestibular schwannoma is the most common lesion, it presents as a rounded mass centered along the axis of the internal acoustic meatus, the largest portion being in the cerebellopontine angle. The tumor enhances after Gadolinium administration. Meningioma is the second most common tumor; this slow growing mass has a wide attachment to the adjacent dural mater and is dramatically enhanced by contrast. Epidermoid cyst the third mass, is an extra-axial lesion with the signal is similar to the one of cerebrospinal fluid. Other lesions such as lipoma, papilloma, glioma or metastasis account for less than 1% of the cerebellopontine angle cistern tumors in adults.

This article considers the various mechanisms of brain injury and specifies the most efficient radiologic technique for assessing patients, depending on clinical presentation. The brain injuries include either extracerebral and intracerebral lesions. The former require rapid diagnosis and therapy and the latter determine management in an intensive therapy, unit and outcome. Standard X-rays are obsolete. The CT, rapidly performed, is the most relevant imaging procedure for surgical lesions. Cortical contusions and diffuse axonal injuries are underestimated by CT and best depicted by MRI. Only late MRI has a strong correlation with neuropsychological outcome. In terms of prognosis, MRI needs to be evaluated. The indications include: a) unstable neurological status: CT; b) moderate head injury: CT may help to decide hospital admission; c) severe head injury: initial CT may be followed by MRI; d) long-term consequences: MRI. Special Indications: a) angio-MRI: suspicion of vascular lesion; b) CT with thin slices and bone window: depressed skull fracture; c) teleradiology (image transfer): to decide a patient transport from a peripheral hospital to a neurosurgical centre. In conclusion, CT remains the first-line examination to detect immediately life-threatening lesions. MRI is the examination of choice for full assessment of brain lesions.

We review the main cerebral parasitic diseases, with emphasis on the most frequently encountered in Europe.