Imaging characteristics of noncontained migrating disc fragment and cyst

The purpose of this article is to review less common presentations of degenerative disc disease on MR imaging. The images of eight patients were retrospectively analyzed. Six of them had transligamentous (or noncontained) disc herniations, the fragments of which were located in the posterior epidural space in three of them. One patient had a transdural disc fragment and one patient had a disc cyst. The cyst was located in the ventrolateral epidural space. On T2-weighted images, the migrated disc fragment returned a higher signal than the disc of origin in 6 of 7 patients. The disc cyst returned a signal similar to that of cerebrospinal fluid. The MR appearances of disc fragments can be puzzling, particularly if they are located in the posterior epidural space. It is important to recognize the abnormalities in order to differentiate them from less common lesions such as hematoma, abscess and neurinoma.

Magnetic resonance angiography of the intracranial vessels

In this overview the results and indications of Magnetic Resonance Angiography of the intracranial vasculature will be discussed. The value of MRA will be studied in the visualisation of normal variants of the cerebral anatomy, the imaging of cerebrovascular disease, the diagnosis of aneurysms and cerebral arteriovenous malformations, the preoperative setup of cerebral tumors and the demonstration of vascular compression.

Retinitis pigmentosa in association with acromegaly: a case report

Retinal abnormalities, unrelated to visual pathway compression, in acromegalic patients were originally described by Small in 1972 (Smail JM. Primary pigmentary degeneration of the retina and acromegaly in a case of pituitary adenoma. Br J Ophthalmol 1972; 56: 25-31). He illustrated a case of primary pigmentary degeneration of the retina occurring in a patient with a chromophobe adenoma of the pituitary gland. To the best of our knowledge this remains the sole, published case of this association. We report on two male patients, with an acromegalic appearance, one caused by a pituitary adenoma, the other associated with a Rathke's cleft cyst, presenting to our department of ophthalmology with the clinical picture of pigmentary degeneration of the retina.

Symptomatic unilateral dolicho-ectasia of the intracranial arteries in a child

Dolicho-ectasia of the left posterior cerebral artery and internal carotid artery in a 5-year-old boy is reported. There was compression of the brainstem, the mammillary bodies and the optic tract. The value of MR angiography in the diagnosis of this vascular anomaly is demonstrated. Dolicho-ectasia of more than one cerebral artery in a child is extremely rare.

Endovascular treatment of a ruptured paraclinoid aneurysm of the carotid syphon achieved using endovascular stent and endosaccular coil placement

We herein report a case of a ruptured superior hypophyseal aneurysm of the left supraclinoid carotid artery that could not be treated with a Guglielmi detachable coil (GDC), even in combination with a supporting nondetachable balloon. After an unsuccessful attempt at surgical clipping, treatment consisted of the placement of a stent over the neck of the aneurysm, advancement of a microcatheter through the stent mesh, and endosaccular embolization with a GDC. The late clinical outcome was excellent.

Magnetic resonance imaging in psychiatry

Recent technical advances in MR imaging have led to several new applications in psychiatric imaging. There is a renewed interest in the further elucidation of the etiopathogenesis of some psychiatric disorders and clinical-radiological correlations are increasingly reported. Volume measurements are frequently used and in the near future, functional MR imaging carries high expectations. A brief survey is given of the recent applications of these new techniques in schizophrenia, affective disorders, dementia, anorexia nervosa, and other less common disorders.

Acute hydrocephalus in nonketotic hyperglycinemia

We present four patients with typical neonatal onset non-ketotic hyperglycinemia (NKH) who developed hydrocephalus requiring shunting in early infancy. Brain imaging revealed acute hydrocephalus, a megacisterna magna or posterior fossa cyst, pronounced atrophy of the white matter, and an extremely thin corpus callosum in all. The three older patients had profound developmental disabilities. This suggests that the development of hydrocephalus in NKH is an additional poor prognostic sign.

Direct caroticocavernous fistula and traumatic dissection of the ipsilateral internal carotid artery: endovascular treatment

After severe craniocerebral trauma a 14-year-old boy developed progressive exophthalmos with venous congestion and chemosis, due to a direct caroticocavernous fistula. Angiography revealed traumatic occlusion of the ipsilateral internal carotid artery and absence of the inferior petrosal sinus. After failure of an approach via the anterior and posterior communicating arteries, the cavernous sinus was successfully catheterised through the occluded internal carotid artery, and embolisation performed with coils.

Septo-optic dysplasia in combination with a pigmented skin lesion: a case report with nosological discussion

In this case report a patient with bilateral optic nerve hypoplasia, schizencephaly and a pigmented skin lesion is described. The diagnosis of de Morsier syndrome or septo-optic dysplasia is put forward on the basis of the diagnosis of optic nerve hypoplasia. The differential diagnosis with Jadassohn's naevus phakomatosis is discussed. The importance of direct ophthalmoscopy of optic nerve abnormalities is stressed, as well as of magnetic resonance imaging, which has become a guideline in the classification of this syndrome.

Primary brain stem tethering: a rare cause of geniculate neuralgia

This rare case of brain stem tethering presented with chronic and progressive geniculate neuralgia. In view of the fact that an occipital subcutaneous lipoma had been resected in childhood, it probably concerned a primary tethering, fitting in with an occult occipital dysraphism. Magnetic resonance imaging (MRI) clearly demonstrated an underlying tethering, causing a distortion of the brain stem. Consequently, this led to the hypothesis that the geniculate neuralgia could be explained by traction on the lower cranial nerves secondary to the brain stem displacement. Untethering resulted in a considerable decrease of the neuralgia. MRI proved to be essential in the diagnosis and treatment of this unusual case.

Automatic 3-D segmentation of internal structures of the head in MR images using a combination of similarity and free-form transformations: Part I, Methodology and validation on normal subjects

The study presented in this paper tests the hypothesis that the combination of a global similarity transformation and local free-form deformations can be used for the accurate segmentation of internal structures in MR images of the brain. To quantitatively evaluate our approach, the entire brain, the cerebellum, and the head of the caudate have been segmented manually by two raters on one of the volumes (the reference volume) and mapped back onto all the other volumes, using the computed transformations. The contours so obtained have been compared to contours drawn manually around the structures of interest in each individual brain. Manual delineation was performed twice by the same two raters to test inter- and intrarater variability. For the brain and the cerebellum, results indicate that for each rater, contours obtained manually and contours obtained automatically by deforming his own atlas are virtually indistinguishable. Furthermore, contours obtained manually by one rater and contours obtained automatically by deforming this rater's own atlas are more similar than contours obtained manually by two raters. For the caudate, manual intra- and interrater similarity indexes remain slightly better than manual versus automatic indexes, mainly because of the spatial resolution of the images used in this study. Qualitative results also suggest that this method can be used for the segmentation of more complex structures, such as the hippocampus.

MRI of non-ischemic vascular disease: aneurysms and vascular malformations

Due to flow-void phenomena, MRI is of great value in the demonstration of cerebral aneurysms and vascular malformations as well as of related parenchymal changes and hemorrhagic complications. Magnetic resonance angiography can produce vascular images which are of importance in the diagnosis and follow-up of the lesions.

Rostral vermian cortical dysplasia: MRI

The MRI findings in rostral vermian dysplasia are described for the first time. Defective foliation and abnormal fissuration of the rostral vermis can clearly be depicted on coronal images. The abnormalities are limited to the anterior lobe of the vermis and its hemisphere extension. A hypothesis is put forward to explain the abnormalities. It is suggested that the vermian changes result from an intrauterine insult at the end of the first trimester. There appears to be a variable degree of expression and associated cerebellar and cerebral cortical abnormalities can be seen. The clinical significance of these findings remains incompletely understood but may be related to the severity of the abnormalities. It is also suggested that a mild degree of vermian rostral dysplasia may represent an incidental imaging finding.

Sciatica caused by a dilated epidural vein: MR findings

We report the MR imaging findings in a 41-year-old woman presenting with sudden low back pain and sciatica. At surgery a dilated epidural vein was found compressing the nerve root. The MR findings may suggest the diagnosis. Magnetic resonance imaging of a dilated epidural vein or varix causing sciatica has not been reported until now.

Diffusion-weighted MRI in sporadic Creutzfeldt-Jakob disease

Diffusion-weighted MRI (DWI) was used in three patients with autopsy-proven sporadic Creutzfeldt-Jakob disease (CJD) to provide a rapid noninvasive way to make this sometimes confusing diagnosis. DWI prompted the diagnosis of CJD at an early stage and appears to be particularly useful for monitoring the progression of the disease. We suggest that patients with suspected CJD and no abnormalities on T2- and proton density-weighted images may have cortical involvement on DWI.

Functional MRI of the brain: localisation of eloquent cortex in focal brain lesion therapy

The aim of this study was to assess the feasibility of functional MRI (fMRI) in a clinical environment on a large patient group, and to evaluate the pretherapeutic value of localisation of eloquent cortex. Forty patients with focal brain lesions of different origin were studied using fMRI. Functional information was obtained using motor, somatosensory, auditory and phonological stimuli depending on the localisation of the lesions. To obtain information about the spatial accuracy of fMRI, the results were compared with postoperative electrocortical stimulation. Two patients with secondary trigeminal neuralgia were scanned using a motor protocol and were implanted with an extradural plate electrode. Imaging was successful in 40 of 42 patients (including the 2 with trigeminal neuralgia). These patients were analysed for strength of activation, the relation of the lesion to activation sites and the presence of mass effect. The correlation between these data and surgical findings provided significant additional clinical information. Functional MRI can be accurately performed in patients with focal brain lesions using a dedicated approach. Functional MRI offers important clinical information as a contribution to a decrease in posttherapeutic morbidity. The accuracy of the technique can be confirmed by other modalities, including invasive cortical electrostimulation.

Cranial CT revisited: do we really need contrast enhancement?

The aim of this study was to define guidelines for intravenous contrast administration in cranial CT, as currently there are no recent guidelines based on a large series of patients. In 1900 consecutive patients (1480 adults and 420 children) pre- and post-contrast scan was analysed in order to assess the contribution of contrast enhancement to the diagnosis. The findings were grouped according to whether abnormalities were seen on the pre- and/or post-contrast scan, or whether no abnormalities were seen at all. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of a pre-contrast scan were used to determine validity. Intravenous contrast enhancement only contributes to the diagnosis if a suspicious abnormality is seen on the unenhanced scan or in the appropriate clinical setting (33.6%). In the remaining patients (65.6%) there is no diagnostic contribution, except for a small number of abnormalities (0.8%). These are often anatomical variants and have no therapeutic impact. The number of contrast-enhanced cranial CT examinations can significantly be reduced by using four general guidelines for contrast administration resulting in considerable cost savings without affecting the quality of service to the patient. These guidelines are defined by the clinical findings/presentation or by the findings on the unenhanced scan. The number of contrast-related complications will be reduced, which may have medicolegal implications. These guidelines can be applied in any radiology department.

Spontaneous spinal epidural hematoma associated with thrombolysis and anticoagulation therapy: report of three cases

Three patients with a spontaneous spinal epidural hematoma are presented, one of which is exceptional because it could be attributed to thrombolysis with alteplase. The other two were correlated with oral anticoagulant therapy. Our second case suggests that Morbus Kahler may be an underlying pathology in spinal extradural hematoma. In the third patient neither an obvious 'locus minoris resistentiae' nor a pathological coagulation test could be held responsible for the spontaneous bleeding. All three patients underwent laminectomy and evacuation of the hematoma. Although two of our cases are examples of complete recuperation after late operative intervention, early surgery is preferable. Permanent clinical attention together with a low threshold to perform magnetic resonance imaging (MRI) leads to a quicker diagnosis of spinal epidural hematoma. We show that administration of gadolinium may facilitate correct preoperative localization of the hematoma because there may be contrast enhancement of the hematoma. Finally, the postoperative policy concerning thromboembolic prophylaxis is discussed.

Primary multifocal leptomeningeal gliomatosis

Only nine cases of primary multifocal leptomeningeal gliomatosis (PMLG) have been reported. We describe the first child with malignant features of PMLG who was diagnosed during life. The differential diagnosis based on imaging findings includes infectious and lymphoproliferative disorders.

Fast FLAIR MRI in childhood white-matter abnormalities

We compared a fast fluid-attenuated inversion recovery (FLAIR) pulse sequence with a dual-echo short tau fast inversion-recovery (DESTTIR) sequence in 20 children with white matter abnormalities. Although the overall image quality of DESTTIR images was better, the lesion-to-background contrast was significantly higher with the fast FLAIR pulse sequence and lesion detection was more accurate.

MR of cerebellar cortical dysplasia

MR imaging findings are described in four patients with cerebellar cortical dysplasia. Typically, cerebellar disorganized folia were seen as an irregular bumpy gray-white matter interface. In addition, cystlike cortical abnormalities were observed in two patients and associated supratentorial developmental abnormalities were seen in three patients. To our knowledge, cerebellar cortical dysplasia without supratentorial abnormalities, as seen in one patient, has not been reported before. We suggest that cerebellar cortical dysplasia represents a spectrum of abnormalities ranging from mild to extensive in severity.