EMC - Radiologie最新文献

Ureteral lesions are a rare but very serious complication of various abdominal, pelvic, and even spinal procedures. In clinical terms, they are rarely suspected since the symptoms are non specific and may appear weeks and even months after the injury constitution. Therefore, the diagnosis of an ureteral lesion is often delayed, resulting in an increased morbidity. An ureteral injury may be first diagnosed on CT in a patient evaluated after surgery. In case of high clinical suspicion, CT scanning should include a delayed scan in order to establish the diagnosis of ureteral injury resulting in a urinoma. This may obviate the need for additional invasive imaging studies or unnecessary exploration.

By probing microscopic molecular motions, diffusion-weighted imaging (DWI) is the only method available today that provides noninvasively information on molecular displacements over distances comparable to cell dimensions. Since it measures a parameter different from those assessed by conventional MRI, DWI represents a new imaging technique that goes beyond depiction of neuroanatomy and evaluates function and physiopathology. Image contrast is related to differences in the diffusion rate of water molecules rather than to changes in total tissue water. DWI has proven its high sensitivity in early detection of acute infarction; it is reliable in differentiating acute stroke from other diseases that mimic acute stroke in clinical terms and on conventional MR images. By differentiating lesions with decreased diffusion from those with increased diffusion, DWI is useful in the evaluation of a wide variety of other disease processes including neoplasms, demyelization, traumatic brain injury, intracranial infections. In particular, DWI can distinguish between epidermoid and arachnoid cysts and provides key information for the diagnosis of cerebral abscess. In some clinical situations, DWI data have a prognostic value.

Transjugular intrahepatic porto-systemic shunts (TIPS) have been developed in the 80’s, for the treatment of portal hypertension complications. Their indications include active bleeding from gastro-esophageal varix, and control of refractory cirrhotic ascites, especially in patients awaiting liver transplantation. New indications include hepatic hydrothorax, hepato-renal failure, and the treatment of the Budd-Chiari syndrome. TIPS have been shown to provide better control than endoscopic sclerotherapy, in the prevention of re-bleeding from gastro-esophageal varix and in the treatment of refractory cirrhotic ascites. Complications of TIPS procedures are possible and include encephalopathy, stent occlusion and stenosis. Using Polythetrafluoroethylen covered endoprosthesis (EPTFE) should improve the permeability of the TIPS.

Acute intestinal ischemia is an unusual acute abdominal condition, with a poor prognosis. The liberal use of sonography (US) and CT helps to reduce the bad outcome of this disease. In the both techniques, gut wall changes can be detected as well as main vascular trunks lesions. Gut wall changes include adynamic ileus, wall thickening, absence of blood flow into the thickened intestinal wall. Pneumatosis and portal venous gas are sometimes present, and can be detected with US and CT. Limited or extended thrombosis of the splanchnic vessels (veins and arteries) are visualized, better with CT than with US. In cases of ischemic colitis, chronic stenoses, obstructions and collaterals of the splanchic arteries are observed.

Plain film of the urinary tract is still indicated for the diagnosis of lithiasis and in the postoperative follow-up. Its accuracy depends mainly on the technique used. A good knowledge of numerous pitfalls enables avoiding false positives in the detection of calculi.

Pulmonary tuberculosis (TP) is a common worldwide lung infection. The radiological features show considerable variation, but in most cases they are characteristic enough to suggest the diagnosis. Classically, tuberculosis is divided into primary, common in childhood, and postprimary, usually presenting in adults. The most characteristic radiological feature in primary tuberculosis is lymphadenopathy. On enhanced CT, hilar and mediastinal nodes with a central hypodense area suggest the diagnosis. Cavitation is the hallmark of postprimary tuberculosis and appears in around half of patients. Patchy, poorly defined consolidation in the apical and posterior segments of the upper lobes, and in the superior segment of the lower lobe is also commonly observed. Several complications are associated with tuberculous infection, such as hematogenous dissemination (miliary tuberculosis) or extension to the pleura, resulting in pleural effusion. Late complications of tuberculosis comprise a heterogeneous group of processes including tuberculoma, bronchial stenosis bronchiectasis, broncholithiasis, aspergilloma, bronchoesophageal fistula and fibrosing mediastinitis. Radiology provides essential information for the management and follow-up of these patients and is extremely valuable for monitoring complications.

In current clinical practice, various imaging tools are available to detect small bowel diseases; they include radiography with barium studies and angiography, ultrasonography, computed tomography and magnetic resonance imaging. Currently, the continuous improvement of these methods makes possible detecting subtle structural changes in the surface and the wall of the small bowel. Nevertheless, for economic and medical considerations, radiologists should select the most appropriate method of examination for the clinical presentation.

The hyoid apparatus, located in the anterior part of the neck, suspends at the base of the cranium all the visceral elements of the neck, in particular the aerodigestive tract. The hyoid bone represents the keystone of the hyoid apparatus; it is a fundamental reference mark in the anatomy and the surgery of the neck, and it has an active part in the three essential functions of the aerodigestive die: breathing, phonation, and swallowing. Many radiological techniques can be used for the study of the hyoid bone and the hyoid apparatus: radiography, ultrasonography, video fluoroscopy, tomodensitometry and magnetic resonance imaging. We describe the most currently used regarding their clinical interest. Malformative pathology is most frequently met with the abnormalities of the thyroglossal tract and cervical dysraphies. The cysts of the thyroglossal tract are frequent congenital cysts since they account for 40% of cervical congenital malformations. The differential diagnosis of its median cervical tumefactions are: dermoid cysts, adenopathies, cystic hydromes, hemangiomes and lipomes, laryngoceles, cysts of the second cleft and necrotic adenopathies. Traumatic pathology is almost frequent (strangulation). The tumours of the hyoid bone are rare but several types of osseous tumours have been described in the literature.