[Unusual variation of the splenic artery]

The authors describe an exceptional variation of the splenic artery found on a preoperative angiogram and confirmed after surgery on splenopancreatectomy specimens. Total duplication of the splenic artery is herein reported for the first time and suggest the need for a new classification of digestive arteries anomalies.

Cathétérisme triple axial renforcé des tortuosités cervico-encéphaliques

Tortuous anatomy of the cervicoencephalic vessels can cause failure in 4 to 6% of interventional procedures by slippage of the material back in the aorta, kinking or difficulty to move forward a balloon. stent or microcatheter. We report on an old patient with high vascular tortuosity, referred for embolization of a ruptured aneurysm of the left inferior cerebellar artery. Access wasn't possible until we used a "triple axial system" with a long 7F sheath, positioned in the left subclavian artery and strongly supported by a super stiff guidewire with its distal end floating freely in the vascular lumen. Inside the sheath and parallel to the guidewire, we pushed a 4F catheter till the mid-vertebral artery. The microcatheter-microguide system tracked through it, towards the aneurysm, with the backward tendency being neutralized by the increased stiffness. Our technique presents the advantage of a strong back-up support, without increased risks such as vasospasm, clotting or dissection, since the guidewire serving as a stiff rail, lies exteriorly to the navigated vessel. Efficiency of this elegant and relatively low risk solution has yet to be proved in larger series.

[Vacuolar leucoencephalopathy induced by heroin: 4 cases]

We report 4 cases of toxic leucoencephalopathy after heroin inhalation. The clinical features, which usually occur some days or even longer after the last heroin consumption, are dominated by a cerebellar syndrome. The cerebellar hemispheres are almost always affected; the cerebral hemispheres, the cerebellar peduncles and the pyramidal tract may be affected. Vacuolar demyelination is the morphological substract of the lesions, which are symmmetrical, not contrast enhancing, hypodense on CT scan and hyperintense on T2-weighted MRI. The pathophysiology is unknown and seems different from post-anoxic leucoencephalopathy. The disease is usually progressive leading sometimes to death, but some cases show slow recovery.

Leucoencephalopathy after heroin inhalation. A case with partial regression of MRI lesions

We report the case of a 41 year old patient who developed a severe cerebellar ataxia. MRI findings were suggestive of myelin damage with symmetrical involvement of the cerebellar hemispheres and, to a lesser extent, the decussation of the superior cerebellar peduncles, the corticospinal tracts and the centrum semiovale. He had been inhaling heroin for the last 5 years. Two years after stopping heroin, he showed clinical improvement with partial regression of the MRI lesions. MRI findings of leucoencephalopathy after heroin inhalation are well described in the literature, however longitudinal studies are rare. It is the purpose of this report to show that clinical and MRI features can be characteristic of this leucoencephalopathy and that regression of white matter lesions can be seen after heroin withdrawal.

[Frontal pseudo-tumoral form of adrenoleukodystrophy]

A case of adrenoleukodystrophy in a 9-year old boy revealed by a predominant frontal syndrome is reported. Brain MRI showed an unusual pseudo-tumoral frontal lesion. The diagnosis was confirmed by increased plasma levels of very long chain fatty acids. His young brother had an isolated adrenal insufficiency with normal brain MRI. The frontal predominance of the lesion and the clinical polymorphism of the disease in this family are discussed.

Ophthalmo-acromelic syndrome (Waardenburg) with split hand and polydactyly

We report on a boy with anophthalmia, split hand, oligodactyly, syndactyly and polydactyly: These features are consistent with the diagnosis of the ophthalmo-acromelic syndrome (Waardenburg). However, the hand anomalies have not been reported yet. This observation helps to extend the wide range of expressivity of this rare syndrome.

[Extrapontine myelinolysis: treatment with TRH]

Central pontine and extra-pontine myelinolysis are a well known complication of hyponatremia. Other causes may be present. We report a case of head injury in a 13 year-old girl, who recovered well after surgery for extra-dural hematoma, but presented endocrinological disorders with hyperglycemia followed by a severe hyponatremia. Despite the correction of these metabolic disorders, the patient became comatose, and MRI, on T2 weighted image, showed hyperintense signals in the basal ganglia consistent with extra-pontine myelinolysis. The patient's state remained unchanged for six weeks. Since S. Konno and H. Wakui published cases of myelinolysis who dramatically improved after TRH treatment, the patient was given 0.6 mg i.v daily of TRH for six weeks. Improvement began within a few days, and continued until complete recovery.

[MRI in the diagnosis of osteoid osteoma]

INTRODUCTION

Osteoid osteoma (OO) is a frequently encountered benign bone tumor, seen in young adults with male predominance.

MATERIALS AND METHODS

Nine patients complaining of nonspecific extremity pain underwent MRI examination. The sequences obtained were T1 and T2 weighted spin-echo and T2 weighted gradient echo. A CT scan examination followed in all cases, exploring the region of the abnormal signal seen on MRI. The results of both examinations were compared.

RESULTS

In six of the nine patients (66.6%) MRI showed evidence suggestive of osteoid osteoma, comparable that seen on CT scan. In three patients (33.3%), MRI showed a nonspecific and ill-defined bone marrow signal abnormality. CT cuts focused on those areas of signal abnormality showed the nidus.

DISCUSSION

MRI is more sensitive than CT scan in detecting soft tissue and bone marrow abnormalities adjacent to an osteoid osteoma. This may produce a misleading aggressive appearance on MR images. CT scanning is more specific than MRI, by showing the nidus. In three patients studied, the nidus was only seen by CT, the other six osteoid osteomas were equally seen by CT and by MRI. In our study, MRI revealed abnormalities in all the cases. It was also highly specific for osteoid osteoma in 66.6%.

CONCLUSION

MRI is very sensitive in detecting bone marrow and soft tissue abnormalities, and can suggest the diagnosis of OO in a good number of patients. In the remainder cases MRI guides the CT-scan. CT is more accurate and remains the definite examination for the diagnosis of OO, by showing the nidus.

Tetraamelia associated with a syrinx: fortuitous association or clue?

We report a male infant born at 43 weeks of gestation with tetraamelia. The upper limbs consisted of the presence of very short stumps containing a single bone. The lower limbs were totally absent. There were also a facial hemangioma, mild micrognathia, testis ectopia and osseous malformations. A magnetic resonance imaging exam showed no significant abnormality of the brain but disclosed a cervico-dorso-lumbar syringomyelic cord without any other associated spinal malformation. Teratogenic as well as genetic causes are discussed.

Neuroradiologic investigation of the visual system using magnetic resonance imaging

The aim of this review is to give highlights about technical imaging aspects with which researchers in the neuro-ophthalmologic fields ought to be familiar. After a short overview of history of anatomy of the visual system, a review of the main anatomic details and their corresponding MRI aspects concerning the visual pathways is proposed. Reference lines suitable for MR imaging of the visual system in normal and in diseased states are proposed to orient the neuroradio-ophthalmologic investigations. Brain, cutaneous, and bony landmarks are given to help multimodality imaging approaches, indispensable for anatomofunctional correlations. The neuro-ocular plane is used as the reference for the screening of the visual pathway in its entirety and retained as the orientation of choice for studying orbital optic nerves and eyes. Two other reference lines primarily devoted to temporal lobe imaging, are proposed for the study of the intracranial optic path: the chiasmatocommissural line and the commissural-obex, brainstem axis reference line. Based on brain commissural landmarks present in all vertebrates, these two lines are also helpful in comparative brain anatomic and physiologic studies in vivo as well as in vitro.

[Trichinosis and cerebral sinocavernous thrombosis]

The authors report a case of sino-venous thrombosis occurring in the course of trichinella infection in a 43 year-old man. MRI and angio-MRI showed a right rolandic haemorrhagic infarct and thrombosis of the superior sagittal and left lateral sinuses. Sino-venous thrombosis in such infection appears to be extremely rare. We found 4 reported cases which we compared to the present case. The findings of sino-venous thrombosis in relation with neurotrichinosis is examined.

A survey of different high resolution visualization modes of a volumetric object with applications

In view of the variety of 3D representation techniques, a clinical study was carried out in order to evaluate their respective usefulness. It appears that a single technique cannot be claimed to be valid for all clinical situations and that a combination of representations brings more relevant information. Among the different techniques a clear delineation must be established between those which allow the accurate definition of landmarks (multiplanar reformation, surface representation), and those which do not (integral shading, reconstructed radiology). The main point is the possibility to recognize anatomical landmarks on these latter modes and to choose oblique cut planes in relation to them. Visualization quality is strongly dependent upon the acquisition protocol which must provide a spatial resolution as isotropic as possible.

[Brain morphometry using MRI in Cri-du-Chat Syndrome. Report of seven cases with review of the literature]

The authors present the results of a morphometric study of the brain of 7 patients with cat cry syndrome, explored with Magnetic Resonance Imaging (MRI). A method is proposed in order to facilitate the identification of the anatomical slices. A characteristic anomaly is observed as a marked atrophy of the brainstem predominating at the pontine level and associated with a small cerebellum, atrophic middle cerebellar peduncles and cerebellar white matter. This apparently systematized atrophy obvious in children, seems similar to the one observed in patients presenting a olivopontocerebellar atrophy, possibly correlating with disturbance of coordination and developmental delay in motility as observed in these patients. This does not implicate the same subjacent functional neuroanatomical pathways.

A new cephalic reference plane for use with magnetic resonance imaging: the chiasmato-commissural plane

A cephalic reference plane is described through the chiasmatic notch and the posterior commissure, which is easily identified on mid-sagittal cuts using magnetic resonance imaging. The horizontal cuts so obtained are almost parallel to the lateral fissure and are perpendicular to the axis of the brain stem.

[Eye movements: initial dynamic approach in high resolution magnetic resonance imaging]

New MR softwares allow a dynamic display of different fonctionnal anatomical regions. This work is a first attempt to visualize the ocular movements. A video tape constitute the support of our results. Technically, the work is performed on a Signa 1,5 T GE CGR System. During each MR acquisition, the subject is asked to fix his gaze successively on each spot of a scale set inside the bore of the magnet. Twenty four images are performed to show the entire lateral course of the globes. The examination time is about half an hour. The video display show the movements of agonist and antagonist muscles, the eyeballs and the optic nerves displacements, in the axial neuro-ocular plane (NOP). Different clinical applications of this new method are discussed (muscular surgery...).

[Etiologic diagnosis of oculomotor paralysis by computerized tomography: a statistical approach. Apropos of 472 cases]

Among 4,538 neuroradiology cases gathered at the NOHC of the XV-XX, an oculomotor paralysis is the 3rd (37.65%) clinical circumstances justifying a computerized tomography (directional plane by the neuro-ocular plane or PNO). The interpretation of the investigations requires to index them in 7 groups of items, therefore a computerized access follows (cross-sorting data). The injury of the VI overcomes (39.61%) followed by the one of the III (33.68%), and the IV (6.35%). In spite of limitations, the study puts forward and debates about etiological frequencies sometimes different from those in the literature.

Fetal curarization for prenatal magnetic resonance imaging

Fetal magnetic resonance (MR) imaging was performed at 33 weeks of gestation for investigation of a posterior fossa abnormality found at ultrasound screening. Fetal movements were abolished by vecuronium injected under ultrasound guidance into the umbilical vein. MR images showed atrophy of the left cerebellar lobe with cisternal dilatation. These were confirmed postnatally by CT scan.

[Cerebral MRI in the study of prognostic factors in AIDS. Hypotheses from tests on 15 patients]

In an attempt to determine factors of predictive value in HIV (human immuno-deficiency virus) seropositive patients, particular attention was payed to symptoms indicating early involvement of the central nervous system (CNS). A cohort of healthy carriers was thus constituted. Follow-up will be carried out every six month including clinical, biological as well as CNS imaging by NMR. Among the first 15 of them, abnormalities could be observed in 4 individuals. Lesions consisted in nodules of high signal in T2 which were localized either in the white matter or thalamic nuclei. No relationship could be demonstrated between the existence of these lesions and various criteria such as age, sex, risk factors and T4 cells count. Such lesions appeared similar to the localizations observed in multiple sclerosis or to the scars of limited vascular accidents. The nature of these lesions is not clear. They certainly indicate early involvement of CNS after primary infection by the HIV virus. They may either represent sequellae of this primary infection or early alterations announcing developing encephalopathy.

[Magnetic resonance imaging of the head compared with the CT scan]

After the description of the normal head anatomy in MRI and its exploration plans, the images observed in benign and malignant tumours of the brain, in cerebral ischaemic attacks, in the diseases of the orbit, face and skull base, are considered. The limits and present indications of the technique are defined.