Imaging of epilepsy following electrical injury.

Electrical injury may result in brain injury with delayed symptoms and sequelae. We report a case of high-voltage cerebral electrical injury in a 42-year-old man through his right hand with delayed symptoms and with imaging abnormalities suggesting that haemorrhage had occurred on the cortical somatosensory areas of his left cerebral hemisphere. An appropriate patient's clinical history should be obtained to correlate the lesions to the event as delay between the event and the symptoms can be very long.

Functional MRI activation of somatosensory and motor cortices in a hand-grafted patient with early clinical sensorimotor recovery.

The aim of this study was to investigate somatosensory and motor cortical activity with functional MRI (fMRI) in a hand-grafted patient with early clinical recovery. The patient had motor fMRI examinations before transplantation, and motor and passive tactile stimulations after surgery. His normal hand and a normal group were studied for comparison. A patient with complete brachial plexus palsy was studied to assess the lack of a fMRI signal in somatosensory areas in the case of total axonal disconnection. Stimulating the grafted hand revealed significant activation in the contralateral somatosensory cortical areas in all fMRI examinations. The activation was seen as early as 10 days after surgery; this effect cannot be explained by the known physiological mechanisms of nerve regeneration. Although an imagination effect cannot be excluded, the objective clinical recovery of sensory function led us to formulate the hypothesis that a connection to the somatosensory cortex was rapidly established. Additional cases and fundamental studies are needed to assess this hypothesis, but several observations were compatible with this explanation. Before surgery, imaginary motion of the amputated hand produced less intense responses than executed movements of the intact hand, whereas the normal activation pattern for right-handed subjects was found after surgery, in agreement with the good clinical motor recovery.

[Role of new MRI techniques in neuroradiologic practice]. / Place des nouvelles techniques IRM en pratique courante neuroradiologique.

Magnetic Resonance Imaging (MRI) has been introduced in clinical practice in the mid-eighties. However, MRI is an ever evolving imaging technique with constant new developments allowing broadening of clinical applications. In particular, angio-MRI involves many different acquisition techniques that will guide their clinical use. On the other hand, clinical applications of the following techniques are briefly discussed: diffusion, perfusion, tractography and diffusion tensor imaging, spectroscopy and functional imaging.

[New findings in cardiovascular imaging]. / Nouveautés en imagerie cardiovasculaire.

Many technologic improvements have allowed cardiovascular imaging to be more efficient and less invasive, especially in cardiac imaging. The main application fields are described. Advantages and disadvantages of two complementary imaging techniques are highlighted: CT-scanner and magnetic resonance imaging.

[Superior oblique myokymia secondary to neurovascular compression]. / Myokymies du grand oblique secondaires à une compression neuro-vasculaire.

In a patient with superior oblique myokymia, a contact is visualised between the right trochlear nerve and a vascular structure by high resolution thin slices magnetic resonance images coupled to angio-MR. A similar contact is not visualised on the left side. This suggests that the neuro-vascular contact is the cause of this superior oblique myokymia and offers the possibility of neuro-surgical decompression if necessary.

Unusual CT features of dermoid cyst in the posterior fossa.

A dermoid cyst of the posterior fossa in a 73-year-old man is reported. The presentation of the cyst was unusual because of the age of the patient, the spontaneously hyperdense aspect of the mass on CT, the partial rim enhancement of the lesion, and the presence of perilesional edema. On pathologic examination, the cyst contained small amount of fat, hairs, necrosis, and small areas of hemorrhage. The amount of hemorrhage found could not explain the spontaneous hyperdensity of the lesion found on CT. The hyperdensity may be related to high protein content of the lesion.

[Spontaneous regression of an acute spinal subdural hematoma. MR imaging]. / Régression spontanée d'un hématome sous-dural aigu rachidien. Données de l'IRM.

We report a case of acute spinal subdural hematoma which developed then regressed spontaneously. MR imaging contributed essential information for diagnosis and follow-up after conservative treatment. We made a short review of the literature and discuss the causes, pathogenesis, clinical presentation and usual treatment of acute spinal subdural hematoma. The differential diagnosis with the more frequent and extradural hematoma requiring immediate surgical evacuation is fundamental.

MRI in multiple sclerosis of the spinal cord: evaluation of fast short-tan inversion-recovery and spin-echo sequences.

We compared the sensitivity of T2-weighted spin-echo (FSE) and fast short-tau inversion-recovery (fSTIR) sequences in detection of multiple sclerosis of the spinal cord in 100 consecutive patients with clinically confirmed multiple sclerosis (MS); 86 patients underwent also brain MRI. In all, 310 focal lesions were detected on fSTIR and 212 on T2-weighted FSE, spinal cord lesions were seen better on fSTIR images, with a higher contrast between the lesion and the normal spinal cord. In 24 patients in whom cord plaques were shown with both sequences, the cranial study was normal or inconclusive. Assessment of spinal plaques can be particularly important when MRI of the brain is inconclusive, and in there situations fSTIR can be helpful.

Posterior extradural migration of extruded thoracic and lumbar disc fragments: role of MRI.

We report three patients with a sequestrated disc fragment posterior to the thecal sac. The affected disc was lumbar in two cases and thoracic in the third. Disc fragment migration is usually limited to the anterior extra dural space. Migration of a disc fragment behind the dural sac is seldom encountered. MRI appears to be the method of choice to make this diagnosis. The disc fragments gave low signal on T1- and slightly high signal on T2-weighted images and showed rim contrast enhancement. The differential diagnosis includes abscess, metastatic tumour and haematoma.

Is there a dural wall between the cavernous sinus and the pituitary fossa? Anatomical and MRI findings.

We compared MRI studies of the sellar area and embryological and adult histological studies of the cavernous sinuses and pituitary fossa. MRI studies were performed in 50 normal subjects with coronal sections using a fast inversion-recovery sequence to demonstrate the dural walls of the cavernous sinus and pituitary fossa. With this sequence, dura mater appears as a high-signal linear structure. The lateral and superior walls of the cavernous sinus was easily identified on all studies, but demonstration of a dural wall separating the cavernous sinus from the pituitary fossa was not possible. These results correlated well with embryological and adult histological studies obtained from 14 specimens. The absence of a strong separation between the pituitary fossa and the cavernous sinus explains the high incidence of extension of pituitary tumours to the cavernous sinuses and vice versa.

High signal in the adenohypophysis on T1-weighted images presumably due to manganese deposits in patients on long-term parenteral nutrition.

Hypermanganesaemia is reported in patients on long-term parenteral nutrition. Deposition of manganese, giving high signal on T1-weighted images, may involve the basal ganglia. MRI in nine patients (mean age 51 years, range 31-75 years) on long-term parenteral nutrition (mean duration 30 months, range 6-126 months), demonstrated high signal in the anterior pituitary gland on T1-weighted sagittal and coronal images. The gland appeared normal on T2-weighted images. Signal intensity in the basal ganglia on T1-weighted images was increased in all patients. Endocrine assessment showed no significant abnormality. Neurological examination showed a mild parkinsonian movement disorder in one patient. Hypermanganaesemia was present in all nine (1.3-2.8 micromol/l, mean 1.87 micromol/l). The high signal in the anterior pituitary gland was probably related to deposition of paramagnetic substances, especially manganese.

[Spinal cord MRI in multiple sclerosis: comparison of turbo-spin echo sequences and turbo-MRI]. / IRM médullaire dans la sclérose en plaques: comparaison des séquences turbo-spin écho et turbo-IRM.

UNLABELLED: To compare T2-weighted turbo spin-echo (turboSE) and turbo inversion recovery magnitude (turboIRM) sequences in the detection of multiple sclerosis of the spinal cord. METHODS: 28 patients with clinically confirmed multiple sclerosis and signs of cervical cord involvement were examined on a 1.5 tesla MR system. Sagittal T2-weighted turboSE sequences were followed by sagittal turboIRM sequences. 24 patients also underwent a cranial study. RESULTS: Using turboIRM sequence, all the patients showed at least one spinal cord plaque with a total of 91 plaques. Using turboSE sequence, 61 lesions were identified in 25 patients. Spinal plaques were seen best on turboIRM sequences with a higher contrast between the lesion and the normal spinal cord. In 10 patients with cord plaques in both sequences, the cranial study was normal or non conclusive. CONCLUSIONS: The turboIRM sequences detect more cord lesions and with a better contrast than the turboSE sequence. This results confirm those described in other studies and demonstrate the inadequacy of the fast spin echo sequences. Assessment of spinal plaques is particularly important when MR findings of the brain are negative or non conclusive.