[Correlation between cranial vault size and brain size over time: preliminary MRI evaluation]. / Evolution comparative de la voûte crânienne et du parenchyme cérébral avec l'âge: étude préliminaire en IRM.

OBJECTIVES: To correlate changes of cranial vault measurements of an adult population during the aging process with brain size using the maximum width of the third ventricle in the axial AC-PC plane. MATERIALS AND METHODS: Prospective study of 126 adult subjects (range: 20 to 80 years) with normal brain MRI and without history of neuropsychiatric disorder. MEASUREMENTS INCLUDED: Cranial vault (Maximum length: Glabella-Opisthocranion, Maximum width: euryon-euryon, and maximum height: Basion-Vertex) measurements and maximum width of the third ventricle in the A C-PC plane. RESULTS: Vault measurements (length, width, high) were similar for every age group, irrespective of gender. The variability of cranial vault measurements between individuals was low (<1 cm). Cranial vault measurements were larger for men, but this was not significant when adjusted for body height Comparatively, a gradual widening of the third ventricle, with an exponential behavior, was observed with advancing age. CONCLUSION: Our results indicate that cranial vault measurements are stable over time (between 20-80 years) comparatively to brain atrophy with advancing age. The low variability of cranial vault measurements and their stability over time should be taken into account during segmentation and normalization of brain parenchymal structures.

Transplant renal artery stenosis. Evaluation of diagnosis with magnetic resonance angiography compared with color duplex sonography and arteriography.

The goal of this study was to assess the value of a three-dimensional phase contrast magnetic resonance angiography (3D PC MRA) for diagnosing transplant renal artery stenosis (TRAS). Twelve consecutive patients clinically suspected of having TRAS were prospectively enrolled during a period of 18 months. Delays from transplantation varied from 3 months to 4 years (mean: 18.3 months). Patients first had color Doppler sonography, then MRA-and, on the following day, intraarterial digital subtraction angiography (IADSA). The site of the maximum peak systolic velocity was noted when doing the report of each color Doppler sonogram. On MRA images, any signal cutoff or any vascular narrowing of more than 50% of the diameter of the vessel was considered to be a significant stenosis. Eight patients were considered to have TRAS on MRA, but only two stenoses were noted on IADSA. The six false-positive results of MRA (due to major intravoxel phase dispersion) were observed when elevated peak systolic velocities were noted on doppler sonograms (mean: 214 cm/sec). These elevated peak systolic velocities were noted in the proximal part of the renal artery when there was a tortuous vessel or a sharp angle between the renal artery and the parent vessel. It is our opinion that 3D PC MRA is of limited value for the diagnosis of renal transplant artery stenosis because of a high number of false-positive results.

Three-dimensional phase contrast MR cerebral venography with zero filling interpolation in the slice encoding direction.

The purpose of this study was to evaluate the magnetic resonance (MR) cerebral venography findings of a three-dimensional phase contrast MR sequence with zero filling interpolation of the data in the slice encoding direction. Fifty volunteers were enrolled in the study. Images were obtained on a 1.5 MR imaging system with acquisition time of 12 min. MIP images were reconstructed throughout the entire imaging volume. A grading scale system was used to assess dural venous sinuses, major deep veins, cortical, and cortical eponymic veins. Inferior group of dural venous sinuses, inferior sagittal sinus, and cortical eponymic veins were poorly demonstrated. Score of the superior sagittal sinus, the straight sinus, the confluence of the superior sinus group, the right transverse and sigmoid sinuses, the internal veins, and the vein of Galen was excellent. The score of the left transverse and sigmoid sinuses was good. In conclusion, when using zero filling interpolation of the data in a three-dimensional phase contrast MR cerebral venography sequence, the superior group of dural venous sinuses and main major deep veins are demonstrated with good conspicuity.

Comparative assessment of digital and analog radiography: diagnostic accuracy, cost analysis and quality of care.

OBJECTIVE: The aim of this study was to compare digital and conventional radiography for diagnostic accuracy, direct costs, and quality of care. MATERIALS AND METHODS: Diagnostic accuracy was assessed by a critical review of the literature on sensitivity, specificity and ROC analysis of these imaging techniques and by a survey with a panel of radiologists. Direct costs and quality of care were evaluated with a before/after study of the implementation of digital radiography in a Department of Radiology in 'Hospices Civils de Lyon' (France). We included 292 patients and measured duration of examinations and direct costs of equipment, films, maintenance and depreciation. To evaluate any changes in working conditions and patient management, a questionnaire was filled out by the staff of the department. RESULTS: Diagnostic accuracy with digital radiography was equivalent to that of conventional radiography but there were wide variations depending on the type of examination. In 1993, although digital radiography resulted in savings of FF 18,000 including tax (US$ 3600) on film consumption for 1 year of examinations, there was a global additional cost of FF 253,000 (US$ 50,600) for maintenance and depreciation. Results showed a nonsignificant tendency to reduced procedure times for all examinations. Working conditions improved, including greater availability for the patient, improved safety, and increased job interest. CONCLUSION: Digital radiography can be introduced into a large hospital to improve patient and staff conditions, at a higher cost than analog radiography, and depending on the type of examinations performed by the radiology department.

Velocimetric and biochemical fetal effects of placental embolisation using microspheres in ewes.

OBJECTIVE: To investigate the reliability of our animal model and study the fetal response to placental ischemia. STUDY DESIGN: Eight monofetal pregnant ewes were fitted with appliances in conformity with a previously defined operating protocol which we have developed. Microspheres at different concentrations were injected through the fetal face of the placenta. The extent of this embolisation was evaluated using biochemical (acid-base balance) and velocimetric criteria (umbilical and carotid arteries). RESULTS: Five fetuses received high concentrations of microspheres and developed acute fetal distress (pH = 6.8 +/- 0.05; PO2 = 6.7 +/- 0.4; (S - D)/S (U.A.) = 1.0; (S - D)/S (C.D.) = 0.58 +/- 0.05). Three fetuses received lower concentrations of microspheres and developed chronic fetal distress (pH = 7.2 +/- 0.02; PO2 = 15 +/- 1; (S - D)/S (U.A.) = 0.75 +/- 0.09; (S - D)/S (A.C.) = 0.62 +/- 0.04). CONCLUSION: Our experimental model is able to reproduce acute and chronic fetal distress. The concentration of microspheres used to create chronic distress is currently understood. Long-term fetal compensation mechanisms prevent the evaluation of risks linked to each degree of chronic distress in utero. The subsequent aim is to obtain a correlation between velocimetric observations and acid-base balance data.

[Malignant pheochromocytoma]. / Phéochromocytomes malins.

The reported incidence of malignant pheochromocytoma varies from series to series. In this series 4 cases (7.2 p. 100) were observed out of a total of 55. In two cases the tumour progressed rapidly but in the other two cases, metastases were detected 3 to 12 years after the apparent cure of a histologically benign pheochromocytoma. The urinary levels of catecholamines and their metabolites gave no indication of the underlying malignancy. The diagnosis was only made from the clinical and radiological detection of metastases (2 hepatic, 2 bone). There is no satisfactory treatment and various therapeutic methods have to be used in succession; surgery for a single metastasis, radiotherapy and antiadrenergic agents to combat clinical manifestations. The natural history of this tumour is relatively long.

[MRI of central nervous system in a series of 58 systemic lupus erythematosus (SLE) patients with or without overt neuropsychiatric manifestations]. / Apport de l'IRM cérébrale dans une série de 58 cas de malade lupique avec ou sans manifestations neuropsychiatriques.

PURPOSE: Central nervous (CNS) involvement in SLE is common and can be evaluated with MRI. The primary goal of this study was to evaluate with high-field MRI the CNS involvement in a series of SLE patients with or without neuropsychiatric symptoms. The secondary goal was to detect a possible relationship between MRI and clinical or biological parameters in SLE. MATERIALS AND METHODS: We correlated the clinical and biological parameters of 58 patients with a lupus defined according to the American College of Rheumatology criteria, including 30 with neuropsychiatric manifestations with conventional and modern MRI (including diffusion weighted-images, high-resolution 3D T1 weighted-images). The population studied was compared to a group of 18 normal controls. RESULTS: In 69% of cases, MRI demonstrated involvement of the CNS both in asymptomatic patients (64.3%) and in patients with neuropsychiatric manifestations (73.3%): microembolic signals, cerebral infarctions (associated with the anti-phospholipid syndrome), atrophy, basal ganglia involvement, posterior leucoencephalopathy, subcortical calcification or hemosiderin deposits (T2*), dilated perivascular spaces. CONCLUSION: MRI with adapted sequences clearly demonstrated the cerebral involvement in approximately 70% of SLE patients with or without neuropsychiatric symptoms.

[Postpartum mesenteric-portal thrombosis of pseudotumor presentation]. / Thrombose mésentérico-portale du post-partum à présentation pseudotumorale.

Portal thrombosis complicating delivery has not been reported to date. We report on a 28-year-old woman who presented 15 days after abdominal delivery with an abdominal mass. US, color Doppler and CT showed thrombosis of the superior mesenteric and portal veins. Percutaneous thrombolysis was unsuccessful. US and Doppler follow-up showed progressive portal hypertension with recanalization of the left portal vein.

[An experimental animal model for inducing fetal distress during pregnancy]. / Modèle animal expérimental d'induction de la souffrance foetale pendant la grossesse.

In order to try to understand and treat efficiently pathology in the human pregnant woman the authors have carried out experimental work on animals. Twenty four pregnant ewes with a single fetus were operated on in the last trimester of pregnancy. Fetal distress was provoked by injecting microspheres into the aorta beneath the renal arteries via the femoral route. The first results in terms of survival, by chemical and Doppler measurements were very encouraging. The operation itself was not a significantly disturbing factor, but the injection of microspheres did cause fetal distress. This experiment should be continued.

[Endocrine polyadenomatosis associated with prolactin pituitary adenoma and an intrathyroidal parathyroid adenoma]. / Polyadénomatose endocrinienne associant un adénome hypophysaire à prolactine et un adénome parathyroïdien intrathyroïdien

A pituitary adenoma was removed transsphenoidally from a 20-yr-old woman with secondary amenorrhea, galactorrhea, and hyperprolactinemia. Light and electronic microscopy, immunocytology characterized a prolactin cell tumor. The patient also underwent three surgical explorations for hyperparathyroidism. Only after selective catheterization of thyroid veins with radioimmunoassay for parathormone, an intrathyroidal parathyroid adenoma was found. No other case of proven prolactin adenoma in Wermer's syndrome has been reported.

Clinical relevance of diffusion and perfusion magnetic resonance imaging in assessing intra-axial brain tumors.

Advanced magnetic resonance (MR) imaging techniques provide physiologic information that complements the anatomic information available from conventional MR imaging. We evaluated the roles of diffusion and perfusion imaging for the assessment of grade and type of histologically proven intraaxial brain tumors. A total of 28 patients with intraaxial brain tumors underwent conventional MR imaging (T2- and T1-weighted sequences after gadobenate dimeglumine injection), diffusion imaging and T2*-weighted echo-planar perfusion imaging. Examinations were performed on 19 patients during initial diagnosis and on nine patients during follow-up therapy. Determinations of relative cerebral blood volume (rCBV) and apparent diffusion coefficient (ADC) were performed in the solid parts of each tumor, peritumoral region and contralateral white matter. For gliomas, rCBV values were greater in high-grade than in low-grade tumors (3.87+/-1.94 versus 1.30+/-0.42) at the time of initial diagnosis. rCBV values were increased in all recurrent tumors, except in one patient who presented with a combination of recurrent glioblastoma and massive radionecrosis on histology. Low-grade gliomas had low rCBV even in the presence of contrast medium enhancement. Differentiation between high- and low-grade gliomas was not possible using diffusion-weighted images and ADC values alone. In the peritumoral areas of untreated high-grade gliomas and metastases, the mean rCBV values were higher for high-grade gliomas (1.7+/-0.37) than for metastases (0.54+/-0.18) while the mean ADC values were higher for metastases. The rCBV values of four lymphomas were low and the signal intensity-time curves revealed a significant increase in signal intensity after the first pass of gadobenate dimeglumine. Diffusion and perfusion imaging, even with relatively short imaging and data processing times, provide important information for lesion characterization.

Acute hypertensive encephalopathy with widespread small-vessel disease at MRI in a diabetic patient: pathogenetic hypotheses.

We report unusual magnetic resonance imaging (MRI) findings in a diabetic patient with neglected hypertension and hyperglycemia, presenting with seizures and coma. Outcome was fatal despite intensive care. The MRI findings included bilateral insular and temporo-occipital grey and white matter involvement, and numerous, scattered, lacunar-like lesions involving the peripheral and deep white matter, basal ganglia grey matter, and brainstem. Lesions had a low apparent diffusion coefficient, and some enhanced following contrast injection. Hypertensive encephalopathy with widespread and severe acute small-vessel disease was considered. Pathophysiology is discussed.

Diffusion-weighted magnetic resonance imaging in Marchiafava-Bignami disease: follow-up studies.

Marchiafava-Bignami disease (MBD), an acute toxic demyelination of the corpus callosum in alcoholics, is associated with poor evolution in the majority of patients. We report here the early and late diffusion magnetic resonance imaging (MRI) and apparent diffusion coefficient (ADC) studies of two patients suffering from MBD with favourable outcome. Diffusion and anatomical MRI changes were parallel to the clinical evolution, suggesting that MRI studies can be helpful for diagnosis and follow-up. Unlike in stroke, restricted diffusion on ADC maps does not seem to be a sign of irreversibility.

Coexisting calcified inferior vena cava thrombus and adrenal hemorrhage in the neonate: report of three cases.

Coexisting calcified inferior vena cava (IVC) thrombus and adrenal hemorrhage are uncommon in children. We present three such cases diagnosed by ultrasound in three boys who were born after 41-, 38-, and 38-week gestations, respectively. In all cases the pregnancy and delivery were unremarkable. The birthweight was 3,630 g, 3,210 g, and 3,390 g, respectively. Left adrenal hemorrhage occurred in all cases. Associated left renal vein thrombus occurred in two cases. The mean followup was 8.5 years. In two cases ultrasound showed persistence of a calcified thrombus and residual stenosis of the IVC. In the third case the IVC thrombus had almost disappeared.