[Dose reduction at CT of the lumbar spine using a 320-detector row scanner: initial results]. / Réduction de dose dans l'exploration du rachis lombaire grâce au scanner 320-détecteurs: étude initiale.

PURPOSE: To compare radiation dose and image quality for CT of the lumbar spine between helical CT and wide volume mode scanning with a 320-detector row CT. PATIENTS AND METHODS: Monocenter prospective study on 20 consecutive patients divided into two groups. All 20 patients underwent lumbar spine CT on the 320-detector row scanner (Aquilion One, Toshiba). The CT examinations for group 1 were performed using the wide volume mode with 320 detector rows while the CT examinations for group 2 were performed using a 64-detector row helical CT mode. The acquisition length and delivered dose corresponding to the DLPe (extended dose length product) as well as qualitative and quantitative image quality were compared between both groups. RESULTS: The mean acquisition length was comparable between both groups. There was a significant dose reduction of about 35% for group 1 compared to group 2 (mean DLPe of 970 mGy.cm for group 1 compared to 1503 mGy.cm for group 2, p<0.028) when using the wide volume mode acquisition at 320-detector row CT compared to the 64-detector row helical CT mode. No significant difference was noted for image quality between both groups. CONCLUSION: The acquisition of lumbar CT using the wide volume mode at 320-detector row CT allows significant dose reduction to patients compared to the 64-detector row helical CT mode while preserving image quality.

[Bone marrow edema: definition, diagnostic value and prognostic value]. / L'oedème médullaire: définition, valeur diagnostique et pronostique.

Bone marrow edema is easily identified on MRI. The terminology suggests that the water content of bone marrow is increased when it is T1W hypointense and T2W hyperintense. It is a misnomer since, histologically, the abnormality does not correspond to marrow edema. The histological findings vary based on the underlying etiology and the presence of fibrosis or inflammatory infiltrate is frequent and often predominant. In France, this terminology is used routinely to describe such lesions. The term osteitis is preferred to describe these marrow signal changes in the setting of rheumatic joint diseases. The detection of bone marrow edema is important because of its diagnostic and prognostic value. It occurs in isolation and is reversible in patients with bone contusion and complex regional pain syndrome. It indicates underlying structural damage and may modify management in patients with rheumatoid arthritis or spondylarthropathies. MR scores for disease activity rely mainly on the presence of marrow edema. Finally, diffusion weighted MR allows quantification of marrow edema and could be more sensitive than conventional MRI to detect inflammation. The purpose of this article is to review the imaging features of marrow edema, review the underlying etiologies and its diagnostic and prognostic value.

[Technical considerations for injection of a mixture of iodinated contrast material and Artirem for combined CT and MR arthrography]. / Détermination des conditions d'utilisation d'un mélange contenant un produit de contraste iodé et de l'Artirem en vue de la réalisation combinée d'une arthro-IRM et d'un arthroscanner.

PURPOSE: To determine the influence of 4 independent parameters on signal intensity and density measurements after injection of an arthrography-specific form of gadoterate meglumine and an iodinated contrast material for combined MR and CT arthrography. The parameters included: 1) variations of gadolinium and iodinated contrast agents within the mixture, 2) variations of concentration of the iodinated contrast agent, 3) variation of temperature of the mixture, 4) the type of MR pulse sequence acquired. MATERIALS AND METHODS: The study was performed on a CT using a phantom containing 47 different syringes. Ten separate mixtures of gadolinium and iodinated contrast agents were obtained, each with a 10% change in the respective proportion of each contrast agent. This was repeated 4 times for 4 iodinated contrast agents of different iodine concentration. Two control syringes, 4 mixtures containing 50% normal saline and 50% iodinated contrast material (one for each of the 4 concentrations of iodinated contrast material) and one with a mixture of 50% of normal saline and gadolinium contrast agent. For the MR acquisition, the syringes were separated into 4 groups for 4 phantoms. On a 1.5 T MR unit, SE T1W, FSE T2W, PD and 3D FIESTA sequences were acquired. All acquisitions were repeated 2 times, and a 3 different temperatures. RESULTS: The progressive increase in the proportion of gadolinium contrast in the solution was associated with a non-linear increase of signal on T1W, 3D FIESTA, and PD images. The signal intensity reached a plateau at concentrations between 40-60%. Signal variations on the 3D FIESTA sequence were significant. On T2W images, there was an increase of measured signal intensity at low gadolinium concentrations. On CT, there was a linear relationship between density measurements and dilution of gadolinium. The progressive increase of the concentration of the iodinated contrast was associated with increased signal loss on MR and progressive increase of density values on CT. Temperature variations were associated with signal intensity changes on T2W and FIESTA images, but not on T1W images. CONCLUSION: At 1.5 T, a mixture of 50% iodinated contrast and 50% gadolinium contrast corresponded to an acceptable compromise for combined acquisition of MR and CT arthrography.

[Neurogenic muscle hypertrophy: imaging features in three cases and review of the literature]. / Hypertrophie musculaire neurogène: à propos de trois cas, imagerie et revue de la littérature.

OBJECTIVE: To review the literature on well-documented cases of neurogenic muscle hypertrophy in order to define significant features of this disease. PATIENTS AND METHODS: The PUBMED and SCIENCE DIRECT web-sites were used to conduct an inventory of all reported cases of this disease. We entered the key-words "hypertrophy", "muscle" and "neurogenic", and found 48 articles, describing 129 cases. Our criteria of inclusion included hypertrophy of one or several muscles of a lower limb, previous realization of at least one imaging study (CT or MRI) and electromyography of lower limbs; criterion of exclusion was hypertrophy related to hereditary or acquired polyneuropathies. Twenty-five cases were retained for investigation along with 3 recent cases observed in our department. RESULTS: Results show that neurogenic muscle hypertrophy is usually presents with painful enlargement of a calf in a male, aged 32 to 60 years, with previous history of low back pain and sciatica, 68% of the time due to disk herniation or lumbar stenosis. Other clinical findings may include radiation therapy or trauma. CONCLUSION: The symptoms of neurogenic muscle hypertrophy may lead to MRI examination before electromyography. This disease should be included in the differential diagnosis.

[Acquired uterine arteriovenous fistula: report of one case]. / Fistule artério-veineuse utérine acquise: à propos d'une observation.

A case of acquired uterine arteriovenous fistula in a 28 Year old patient is reported that probably is secondary to a "difficult" delivery. Sono-graphic, MRI and angiographic findings are reported, before and after endovascular management.