EMC - Radiologie最新文献

Infection of the spine including any part of the vertebra is called infectious spondylitis. Infectious spondylitis is primarily due to hematogenous spread of organism. The most common pyogenic germ is Staphylococcus aureus. Tuberculous spondylis has become the most frequent manifestation of osteoarticular tuberculosis. Clinical manifestation is often acute or subacute back pain with fever and rigidity over the involved segment. Because of non specificity of the symptoms, the initial plain films are usually normal. However, the earliest radiographics sign remain a blurring of the endplates and a decrease in the disk space height. Magnetic resonance imaging is the imaging modality of choice in assessing spondylodiskitis, especially in the early phase when the bone marrow oedema is detected before the destructive process. Post contrast T1 weighted SE sequences with fat-saturation are useful in epidural involvement or paravertebral abscess. Differential diagnosis include : degenerative disk disease spondylarthropathy and neoplastic disease. A specific microbiologic diagnosis is highly desirable for definitive medical treatment with antibiotics : blood cultures, fluoroscopy or CT-guided percutaneous spine biopsy.

Lower limbs venous anomalies include a group of morphological or functional deteriorations of superficial and/or deep veins, originating from a break in their morphogenesis, at a more or less advanced stage. They belong to the vast register of venous malformations. These sporadic and rare lesions, which may be due to a genetic deterioration with variable expressions, are sometimes latent and fortuitously encountered, or symptomatic and therefore lead to a panel of sever chronic venous insufficiency. They can be isolated or part of a range of complex abnormalities. Their assessment greatly benefited from the use of ultrasound methods and of magnetic resonance imaging, some methods, which enable to distinguish the shapes when therapeutic abstention is recommended and those when a medical treatment, interventional radiology, or surgery is required.

Acute abdominal pain is a common cause of admission in emergency rooms. Modern imaging techniques take a major place in the management of these situations. This chapter presents some aspects of conventional imaging; it develops also the contribution of cross sectional imaging for the diagnostic of acute abdominal diseases in adults. An optimal diagnosis is based on a rational use of sonography and computed body tomography, leading to a reduced number of unnecessary operations. Early diagnosis of common and uncommon acute abdominal diseases helps preventing dramatic evolution such as a perforation.

Innovating technology and strict validation procedures have permitted confirmation of some of the indications of percutaneous endovascular therapeutic techniques and have led to the emergence of new ones. General aspects of these procedures are first reviewed. We then describe revascularisation techniques with an emphasize on material, results, and indications in percutaneous treatment of arterial stenosis, and occlusions. The third chapter is related to percutaneous embolisation techniques for homeostasis, tumor devascularisation, vascular malformations and shunt creations. Finally, other techniques are described such as endografts for the treatment of aortic aneurysms, cava filters, implantable venous access ports, retrieval of endovascular lost objects, TIPS, false aneurysms’treatment by ultrasound guided compression.

Pulmonary metastasis are the most frequent pulmonary malignant lesions. They have a prevalence of 30 to 50% in patients with thoracic or extrathoracic malignancies, this being related with the role of vascular filter of the lung parenchyma. Primary malignancies most often concerned are pulmonary, breast, colonic, pancreatic, kidney, gastric, ENT carcinoma and melanoma. Pleural metastasis represent 95% of malignant diseases of the pleura. Pulmonary, breast, ovarian or gastric adenocarcinoma are most often concerned. Lymphoma may also involve the pleura with possible multifocal localizations and represent a differential diagnosis. Knowledge of mechanisms of drainage and migration of tumoral cells initial site explains the various patterns of lung metastasis. Computed tomography is the best imaging toll for the diagnosis and post-therapeutic follow-up of pulmonary metastasis. In this context of disseminated disease, chemotherapy increases the survival. Surgery may be proposed when disease is localized to the lung and stabilized by chemotherapy. Cases of cure have however been reported after surgery of colonic metastasis without previous chemotherapy.

Breast imaging plays a major role during and after treatment of a breast cancer. Immediate postoperative mammography is required to confirm the complete excision of cancers that contained calcifications. Ultrasound is the best examination for the detection of immediate postsurgical complications such as hematoma, abcess or lymphocele. Post-therapeutic benign changes (surgery, radiotherapy) have to be known for avoiding unusefull invasive explorations. Breast scars, irradiated breast and fat necrosis will be described over time at mammography, ultrasound and MRI. Local treatment failure that occurs within the first 5 to 7 years after treatment is most likely to be located at or near the site of original cancer ; in approximatively 50 % of cases, the local relapse will be detected by suspicious microcalcifications on mammmograms. Local failure after ten years is commonly caused by carcinomas growing elsewhere in the breast. Ultrasound is useful for analyzing architectural distorsion, focal asymmetric breast tissue, post-therapeutic dense breasts or abnormal clinical findings. Magnetic resonance imaging has a high specificity and negative predictive value in this population allowing the elimination of an infiltrating relapse in difficult cases. In these treated patients, quality control of mammograms and comparison with previous imaging data are mandatory at each annual imaging follow-up.

Second-generation ultrasound contrast agents are gas microbubbles that are injected into a peripheral vein and enhance the backscattered ultrasound from the blood vessel lumen. The non-linear signal produced by the bubbles can be differentiated from the tissue signal. No severe adverse events have been reported, and these agents can be used in patients who are at high risk due to heart failure, renal failure, or pulmonary hypertension. In patients with liver disease, contrast-enhanced ultrasonography provides an evaluation of the microvessels within focal nodular lesions and a characterization of benign and malignant lesions similar in terms of semiology and reliability to that obtained with computed tomography. Second-generation contrast agents substantially improve the results of ultrasonography for detecting and quantifying liver metastases. Adaptations to the ultrasound equipment must be made to allow use of these agents.

The finding of a solitary pulmonary nodule is a frequent and difficult problem. Solitary nodules are caused by a variety of conditions, ranging from benign granulomas to lung cancer. Because solitary nodules are often primary bronchogenic carcinoma with only 5-yr survival after resection, it is important to promptly identify malignant nodules. The goals of management are to resect malignant tumors and to avoid unnecessary thoracotomy if the nodule is benign. Evaluation with thin-section CT is first necessary for detailed evaluation including lesion size, contour and edge, calcification and nodule density. When solitary nodule remains of indeterminate origin, the use of non-invasive techniques such as contrast-enhanced CT and positron emission tomography (PET), in detecting nodule enhancement is discussed. Growth rate is of importance in evaluating the nature of a solitary pulmonary nodule, 2-year stability is always considered an indicator of benignity. The Bayesian approach is based on the principles of decision analysis, its estimates the prevalence of malignancy in the population, assesses risk factors predictive of malignancy as demonstrated by history and chest radiograph, and selects a management strategy based on the adjusted probability of malignancy.