[en] This guidebook aims at providing an interpretation frame of NMR images to radiologists in order to homogenize the interpretation and to give help using a fixed and synthetic model in the form of a check list. (J.S.)

[en] The widespread use of computed tomography and the advent of magnetic resonance imagery have considerably modified the methods and strategies of thoracic exploration over the last 10 years. Standard radiography remains the first-line examination for all thoracic diseases, and often is the only imagery required; further explorations are indicated on the basis of the information seen on standard films. Computed tomography has become an essential element in the work-up of all diseases involving a tumoral process in the lung. It is also indicated in bronchiestasis and for the exploration of chronic lung diseases. Further information may be obtained with magnetic resonance imagery. Although this method cannot be used to explore the pulmonary parenchyma, it is particularly adapted in cases involving the pleura, mediastinum (tumours and vessels) and the thoracic wall. Scintigraphy is mainly used to detect pulmonary migrations and to investigate lung function before thoracic surgery. Pulmonary angiography remains the reference imagery for the diagnosis of pulmonary embolism but has lost its other indications. Tomobronchography is exceptionally required. Magnetic resonance images are indicated on the basis of the tomography results and are particularly useful in tumours of the apex and extension to the spinal column or mediastinum. In cases of suspected pulmonary emboli, a normal scintigraphy can eliminate the diagnosis. Inversely, certain teams propose coupling perfusion scintigraphy with ventilation scintigraphy to detect mismatches, particularly distinctive signs of pulmonary emboli. When the diagnosis remains uncertain, pulmonary angiography is the reference imagery technique. (authors)

[en] This paper reports on the diagnostic value of MR imaging in a surgical series of focal nodular hyperplasia and to compare the signal intensity of the scar on MR imaging with histopathologic findings. During the past 3 years, 30 patients underwent liver resection for focal nodular hyperplasia. All patients underwent preoperative MR imaging examination with T1- and T2-weighted sequences. The MR findings of the scar (size, signal intensity) were correlated with the macroscopic and histopathologic results (fibrosis, edema, vessels, inflammation). Surgery disclosed 40 tumors in 30 patients (multiple in 7 cases). MR imaging failed to depict 6 tumors of 2 cm in diameter. Correct diagnosis was made in 12 of the 34 tumors seen with MR imaging (35%). In the other cases, there were atypical features, no scar, hypointense scar on T2-weighted sequences, and peritumoral halo. Macroscopic evaluation off the scar (presence, size) correlated well with the MR imaging findings. Furthermore, in 13 of the 16 hyperintense scars on T2-weighted sequences, microscopic examination revealed predominant edema and vessels. In 4 of the 6 hypointense scars on T2-weighted sequences, microscopic examination revealed a low content of edema and vessels

[en] This paper compares the sensitivity and specificity of MR imaging in identifying intravascular thrombus with spin-echo (SE) images alone, gradient-echo (GRE) images alone, and SE plus GRE images. In 58 patients, 233 veins in the abdominal region were reviewed in a blinded manner by three radiologists using seven levels of certitude for the diagnosis of thrombus. Corroborative studies, available in all cases, proved thrombosis in 75 vessels and flow patency in the other 158. Receiver operating characteristic curves were constructed for the accuracy of the distinction between thrombus and flow signal for SE images alone, GRE images alone, and SE plus GRE images

[en] This retrospective study identified MR imaging characteristics of acute, subacute, and chronic radiation effects in bladder and perivesicle tissue. Fifteen patients underwent MR imaging 1-3 months (n=9), 6-10 months (n=3), and more than 24 months (n=3) after treatment with external beam pelvic radiation. In the acute period, T2-weighted MR imaging revealed diffuse bladder wall thickening and trigonal hyperintensity. In the subacute and chronic periods, both mural thickening and hyperintensity were global, and perivesicle fat intensity was abnormally low. The most severe anatomic abnormalities appeared in the chronic period and reflected confines of therapeutic ports. Knowledge of expected morphologic changes may assist in the evaluation of serial postreatment scans

[en] In this paper to analyze the pitfalls in spin-echo (SE) and gradient-echo (GE) MR imaging, the authors selected the interpretational errors that occurred in a prospective study of 292 abdominal veins (95 thrombosed and 197 patent veins). False-negative diagnoses were related to intermediate or low signal intensity of thrombi with Se, intermediate signal intensity of thrombi with GRE, and nonidentification of small thrombi. False-positive diagnoses were related to ambiguous signal intensity of patient veins with SE and GRE, artifacts from ferromagnetic clips with GRE, and incorrect identification of small patent veins. Distinct patterns of pitfalls are presented and an optimal strategy with a combination of SE and GRE images is proposed

[en] Hepatic Adenoma (HA) and Focal Nodular Hyperplasia (FNH) are rare benign tumors of the liver, occurring mostly in females between 25 and 40 years old. HA is clearly related to oral contraceptive intake. Detection of such tumors may be assessed by Ultrasonography (US). Computed Tomography (CT) or Angiography. These examinations usually allow differenciation with hepatic angiomas but it is much more difficult to rule out a well-differenciated primary liver cancer. MR proved to be a valuable technique for detection of liver tumors. Initial experience suggested that T1 and T2 relaxation times had little value for tissue characterization. The aim of this study is to show the presentation of HA and FNH and to evaluate the possibility for this method to characterize these lesions

[en] A case of insufficiency fracture of the sacrum is reported. These fractures usually occur in elderly women and are secondary to various conditions, mainly postmenopausal or steroid-induced osteoporosis and radiation therapy. They are often overlooked or confused clinically and radiographically with metastatic disease. Findings on plain films are often subtle. Radionuclide bone scan shows a characteristic H or butterfly shaped pattern of increased uptake in the sacral alae. The diagnosis is confirmed by conventional tomograms or CT which show the fracture always surrounded by prominent sclerosis

[en] The diagnosis of acute pancreatitis is based on clinical examination and basic laboratory tests. The main role of sonography in acute pancreatitis is to evaluate gallstones and small fluid collections. However, sonography is frequently difficult due to intestinal ileus related to pancreatitis. CT is indicated early in the clinical course of acute severe pancreatitis when the diagnosis is uncertain or when complications such as abscess, hemorrhage, or necrosis, are suspected. In addition, CT may be used to assess the prognosis and follow-up of patients. (authors). 20 refs., 12 figs., 4 tabs

[en] Pyo-myositis is a primary bacterial infection of skeletal muscle. This infection tends to occur in the large muscles of the lower extremity. Pyo-myositis of the proximal muscles of the thigh can simulate acute abdominal disease. Early diagnosis improves the outcome. Delayed diagnosis may lead to septicemia and shock. We report the CT and MRI findings in a patient with pyo-myositis of the proximal muscles of the thigh. (authors)