This paper discusses the indications for spinal ultrasound, including its advantages and disadvantages compared with spinal MRI. The features and ultrasound findings both in normal infants and in those with spinal dysraphism are reviewed.

This paper discusses the indications for spinal ultrasound, including its advantages and disadvantages compared with spinal MRI. The features and ultrasound findings both in normal infants and in those with spinal dysraphism are reviewed. Spinal ultrasound (SUS) is becoming increas- ingly accepted as a first line screening test in neonates suspected of spinal dysraphism (SD) (1, 2). SUS can be useful in detecting tumours, vascular malformations and cases of trauma; however, as the indication in most cases is to exclude SD, this article will concentrate on this group of abnormalities (2-4). The advantages of SUS are not only a diagnostic sensitivity equal to MRI (2) but that, unlike MRI, SUS can be performed portably, without the need for sedation or general anaesthesia. In addition, MRI is highly dependent on factors affecting resolution, includ- ing patient movement, physiological motion from cerebral spinal fluid (CSF) pulsation and vascular flow, factors that do not affect SUS (5). New generation high frequency ultrasound machines with extended field of view capability now permit imaging of high diagnostic quality in young babies. SD refers to abnormalities with imperfect fusion of the midline neural and bony structures. It is the most common congenital central nervous system abnormality, with myelomeningoceles occurring in up to 2 per 1000 live births in some studies, although the incidence in the Western world is now likely to be lower (5, 6). In infants withoccultSD,earlydiagnosismaybeuseful, asSD may lead to distortion of the spinal cord and nerve roots with growth, resulting in neurological sequelae in the lower extremities, the lower urinary tract and the gastrointestinal tract. Because some paediatric neurosurgeons believe that early surgical correction of SD may avoid these sequelae, early diagnosis of SD could be important (7, 8).

AIM: To assess the diagnostic value of spinal ultrasound in cloacal exstrophy, a caudal malformation which is associated with spinal dysraphism, and to assess the prevalence of spinal dysraphism in cloacal exstrophy. MATERIALS AND METHODS: Ten infants under 1 year old with cloacal exstrophy underwent spinal ultrasound at presentation. Three patients also had a magnetic resonance imaging (MRI) examination. Ultrasound and MRI images were reviewed and correlated. RESULTS: Nine of 10 patients had no external signs of spinal dysraphism. One patient had a clinically apparent myelomeningocele. Five of 10 patients (50%) had spinal dysraphism on ultrasound: there were two patients with a low cord, two with tethered cords and a lipoma, and one patient with tethering and a myelomeningocele. Thus, in four of these five patients spinal dysraphism was occult. In a small number of patients (n=3) MRI was also performed—in these cases the MRI and ultrasound appearances correlated, however MRI was not performed in those patients in whom spinal ultrasound was normal. CONCLUSION: In three cases where spinal ultrasound detected occult dysraphism and MRI was performed, spinal ultrasound and MRI correlated. Advantages of spinal ultrasound include ease of examination, production of high quality multi-planar images and the facility for portable imaging at the bedside. Spinal ultrasound should be the first investigation in all babies with cloacal exstrophy to diagnose occult and non-occult spinal dysraphism.Dick, E. A.et al. (2001).Clinical Radiology56 , 289–294.

Des études approfondies de l'extraction du complexe thiocyanate de molybdène avec la méthylisobutylcétone ont conduit à une méthode améliorée pour le dosage de traces de molybdène dans les sols et les substances géologiques par spectroscopie d'absorption atomique. La méthode est applicable dans le domaine 1–500 p.p.m. de Mo, avec des échantillons de 1 g, donnant des écarts types relatifs n'excédant pas environ 8% au niveau de 1 p.p.m. La limite de détection est 0,1 p.p.m. Il y a peu d'interférences, et de grandes quantités de fer sont sans influence.