EMC - Radiologie最新文献

A good knowledge of ovarian anatomy and physiology is needed to understand functional disorders of the ovaries. Functional alterations occur mainly in women with genital activity. Such ovarian disorders are dramatically frequent. They are not associated with organic lesions and usually recover spontaneously or with appropriate medical treatment.

Spiral angio CT has become the first choice imaging modality to investigate the pulmonary arterial circulation. Concerning pulmonary embolism, thin slice imaging and, recently, multi-slice angioCT have improved the diagnosis accuracy at the sub-segmental level. The diagnosis of tumoural involvement of the pulmonary arteries and the depiction and characterization of arterio-venous malformations relies on spiral CT. The non-invasive analysis of pulmonary flow and velocities is possible using MRI. Angio MR with injection of gadolinium also provides high quality images of the central pulmonary arteries. The use of digital subtracted angiography is restricted to endovascular procedures such as embolization of arterio-venous malformations and aneurysms and occlusion of pulmonary arteries in case of severe bleeding from the pulmonary vasculature.

Imaging has a significant role in the diagnosis and more particularly in the evaluation of the therapeutic possibilities and prognosis of cranio-encephalic tumours (CET). After surgery, it is used at the same time to evaluate the tumour resection and to consider the associated treatments. In the follow-up, imaging allows to appreciate the answers and the complications of these therapies. MRI is currently unanimously recognized as the examination of choice for the diagnosis and the follow-up of CET. The diffusion and perfusion MRI techniques, available on the modern imagers are easily realizable in clinical practice. They bring further information basically different from those provided by morphological imaging, particularly interesting for the diagnosis but also during the follow-up of these lesions.

Diffuse liver diseases refer to various diseases that induce hepatic intra or extra cellular infiltration. The most frequent are steatosis and iron overload, which can be observed in genetic hemochromatosis or in other hepatosiderosis. There are other infrequent infiltrations such as Wilson disease, glycogenosis or amylosis. Liver fibrosis and cirrhosis can also be included in this group of diseases.

After a brief review of tools used to measure radiation, we present the parameters of helical scan radiation (single and multiple slice): technical parameters (voltage, tube current) and spatial parameters (X-ray beam geometry, slice thickness, pitch). Their influence on radiation is discussed, as well as methods for adapting these parameters to obtain optimal balance between dose and imaging quality.

Congenital malformations of the kidney and upper urinary tract in children are described. Anatomical characteristics are reported, in addition to consequences on the renal function, clinical presentation, the imaging techniques used in 2004 for their diagnosis and complete evaluation, and the criteria for making therapeutic decision.

Radiological signs are important aspects of anemia in children, malignant diseases being excluded. Among these signs, osseous manifestations may be a diagnostic clue in haemoglobin disorders such as sickle-cell disease or thalassemia. In both, medullar expansion may be observed, with cortical thinning related to medullar hyperplasia. In case of homozygoteous thalassemia, extra-medullar haematopoiesis mainly in the mediastinum can be also observed. In sickle-cell disease the images are partly related to medullar hyperplasia but also to thrombosis and bone infarcts. The location of these signs follows the process of conversion from red marrow to fatty marrow. So it will start at the extremities to involve in adolescents the spine and the proximal epiphysis of the limbs. The main complication is a superimposed infection of the infarcted areas. The differential diagnosis between infection and pure necrosis is very difficult in such patients.