Apprendre à réaliser des fiches pratiques utilisables sur son PDA pour faciliter l’interprétation des dossiers radiologiques dans la pratique quotidienne. Ordinateur PC et PDA sous Palm OS. Les PDA (Personal Digital Assistant) sont de plus en plus répandus, leur taille, guère plus importante qu’un carnet de poche, leur capacité d’afficher à la fois textes et images en font un aidemémoire idéal pour le radiologue qui dispose de références toujours disponible. Le but de cette présentation est d’expliquer comment réaliser soi-même des fiches d’aide-mémoire exploitables sur PDA. Un aide-mémoire sur les pneumopathies infiltrantes diffuses est proposé comme exemple. La réalisation de fiches d’aide-mémoire est simple et permet d’avoir toujours ses références à portée de main.

Neurocysticercosis is a leading cause of seizures and epilepsy in the developing world and is an increasingly important health issue in the United States. Recent results from the Cysticercosis Working Group in Peru provide new evidence supporting the use of antiparasitic agents in highly selected patients with active cysts and seizures.

PURPOSE:Rathke's cleft cysts are non neoplastic lesions of the sellar area that seldom are symptomatic. Their incidence has been underestimated before magnetic resonance imaging (MRI). The aim of this work was to assess the value of MRI in the diagnosis and differential diagnosis of Rathke's cleft cyst based on a retrospective review of 12 cases and a review of the literature.PATIENTS AND METHODS:We retrospectively reviewed the MRI features of 12 patients with Rathke's cleft cyst collected over 4.5 years. Patients included ten females and two males (mean age: 39 years). The most common presentation was the association of dysmenorrhea and pituitary dysfunction. MRI examinations were performed using a 1.5 Tesla system, T1 and T2 weighted sequences performed before and after Gd- DTPA injection. Signal intensity, shape, size and location of the lesion were analyzed.RESULTS:In all cases, MRI examination showed a cystic lesion of variable size and signal intensity. The cyst was purely intrasellar in nine cases and a suprasellar extension was noted in three cases. Five patients underwent surgery providing pathological confirmation, four underwent routine follow-up and three were lost of follow-up.CONCLUSION:We conclude that MRI is an efficient tool for diagnosis, allowing appropriate medical decision making.

Tumors of the cerebellopontine angle (CPA) are frequent; acoustic neuromas and meningiomas represent the great majority of such tumors. However, a large variety of unusual lesions can also be encountered in the CPA. The site of origin is the main factor in making a preoperative diagnosis for an unusual lesion of the CPA. In addition, it is essential to analyze attenuation at computed tomography (CT), signal intensity at magnetic resonance (MR) imaging, enhancement, shape and margins, extent, mass effect, and adjacent bone reaction. CPA masses can primarily arise from the cerebellopontine cistern and other CPA structures (arachnoid cyst, nonacoustic schwannoma, aneurysm, melanoma, miscellaneous meningeal lesions) or from embryologic remnants (epidermoid cyst, dermoid cyst, lipoma). Tumors can also invade the CPA by extension from the petrous bone or skull base (cholesterol granuloma, paraganglioma, chondromatous tumors, chordoma, endolymphatic sac tumor, pituitary adenoma, apex petrositis). Finally, CPA lesions can be secondary to an exophytic brainstem or ventricular tumor (glioma, choroid plexus papilloma, lymphoma, hemangioblastoma, ependymoma, medulloblastoma, dysembryoplastic neuroepithelial tumor). A close association between CT and MR imaging findings is very helpful in establishing the preoperative diagnosis for unusual lesions of the CPA.

The central canal of the spinal cord is present at birth and becomes progressively obliterated. Cadaver studies have shown that it may persiste partially or completely. To our knowledge, this entity has not been described on MRI. We reviewed 794 MRI studies of the spinal cord, and found 12 patients (aged 14 to 65 years) who had an intramedullary cavity. The cavity was at the junction of the ventral 1 / 3 and dorsal 2 / 3 of the spinal cord, except at the level of the lumbar enlargement, where it was central. It was filiform in most cases, although sometimes fusiform (3 to 4 mm in diameter), and had regular contours. The cavity were thoracic in 69 % of cases. The clinical features were totally unrelated to the image, and there were no anatomical factors (Chiari malformation, dysraphism) predisposing to syringomyelia. The images were perfectly compatible with a persistent central canal, which we interpret as a variant of normal anatomy. Therefore it is important to regard these findings as normal, to avoid unnecessary treatment and follow-up.

BACKGROUND AND PURPOSE: CSF circulation has been reported to represent a major factor in the pathophysiology of syringomyelia. Our purpose was to determine the CSF flow patterns in spinal cord cysts and in the subararachnoid space in patients with syringomyelia associated with Chiari I malformation and to evaluate the modifications of the flow resulting from surgery.METHODS: Eighteen patients with syringomyelia were examined with a 3D Fourier encoding velocity imaging technique. A prospectively gated 2D axial sequence with velocity encoding in the craniocaudal direction in the cervical region was set at a velocity of +/- 10 cm/s. Velocity measurements were performed in the larger portion of the cysts and, at the same cervical level, in the pericystic subarachnoid spaces. All patients underwent a surgical procedure involving dural opening followed by duroplasty. Pre- and postoperative velocity measurements of all patients were taken, with a mean follow-up of 10.2 months. We compared the velocity measurements with the morphology of the cysts and with the clinical data. Spinal subarachnoid spaces of 19 healthy subjects were also studied using the same technique.RESULTS: A pulsatile flow was observed in syrinx cavities and in the pericystic subarachnoid spaces (PCSS). Preoperative maximum systolic cyst velocities were higher than were diastolic velocities. A systolic velocity peak was well defined in all cases, first in the cyst and then in the PCSS. Higher systolic and diastolic cyst velocities are observed in large cysts and in patients with a poor clinical status. After surgery, a decrease in cyst volume (evaluated on the basis of the extension of the cyst and the compression of the PCSS) was observed in 13 patients. In the postoperative course, we noticed a decrease of systolic and diastolic cyst velocities and a parallel increase of systolic PCSS velocities. Diastolic cyst velocities correlated with the preoperative clinical status of the patients and, after surgery, in patients with a satisfactory foraminal enlargement evaluated on the basis of the visibility of the cisterna magna.CONCLUSION: CSF flow measurement constitutes a direct evaluation for the follow-up of patients with syringomyelic cysts. Diastolic and systolic cyst velocities can assist in the evaluation of the efficacy of surgery.

MRI is the best imaging method to evaluate syringomyelia. It is important to study from the posterior cranial fossa to the sacro-lumbar region and also the supra-tentorial structures. This complete analysis is essential to classify the syringomyelia and to investigate other associated malformations. Radiographs and CT scan are useful to analyze bone structures. For MRI, the new sequences with phased-array coils are also very important to study the entire spinal cord and the posterior fossa. It is essential to study the spinal cord with sagittal and axial spin echo T1 and fast spin echo T2 weighted images with sometimes coronal view, particularly when the patient presents a scoliosis, to have a correct morphological and functional evaluation. MRI gives an excellent study of the spinal cord with an excellent analysis of a primitive or foraminal syringomyelia, but also traumatic, infectious or post arachnoiditis syringomyelia. Spin echo T1 weighted images with injection of gadolinium can be used if an intra-medullary tumor is suspected. MRI is also useful for the post-operative follow up to evaluate the persistence of the medullary cyst and the enlargement of the foramen magnum.

Results of CT and MRI explorations in 8 patients with cerebrospinal fluid (CSF) fistulae are reported and compared with surgical findings in 7. Sensitivity of MRI (CISS and fast T2 spin-echo sequences) was excellent giving perfect correlations with surgical findings in 7/7 cases. CT and MRI were found to provide complementary information suggesting they should be used in combination as first intention explorations of suspected CSF fistulae. Computerized cisternography should be used if MRI is contraindicated or if a clinically and biologically proven CSF fistulae is not visualized by CT or MRI.

Results of CT and MRI explorations in 8 patients with cerebrospinal fluid (CSF) fistulae are reported and compared with surgical findings in 7. Sensitivity of MRI (CISS and fast T2 spin-echo sequences) was excellent giving perfect correlations with surgical findings in 7/7 cases. CT and MRI were found to provide complementary information suggesting they should be used in combination as first intention explorations of suspected CSF fistulae. Computerized cisternography should be used if MRI is contraindicated or if a clinically and biologically proven CSF fistulae is not visualized by CT or MRI.