Massive obesity in adolescents: dietary interventions and behaviours associated with weight regain at 2 y follow-up.

OBJECTIVE: To compare the influence of weight-reducing diets containing different amounts of protein and CHO on body composition in obese adolescents and to examine dietary and physical activity behaviours during follow-up. DESIGN: Prospective randomised study comparing two weight-reducing diets with the same energy (1750 kcal) and fat (31%) content, but different protein and carbohydrate contents: PROT- (15% protein, 54% CHO) vs PROT+ (19% protein, 50% CHO). PATIENTS: Massively obese 11- to 16-year-old children (32 boys and 89 girls). SETTING: A 9-month treatment in a medical centre (boarding school) plus a 2-y follow-up in free-living patients examined at home 1 and 2 y after treatment. MEASUREMENTS: Anthropometry, bioelectrical impedance, nutritional intakes and physical activity. RESULTS: Of the 121 eligible children (61 in PROT- and 60 in PROT+), 82% completed the trial until the end of weight loss treatment and 60% were followed 2 y after treatment. Body mass index (BMI) value at inclusion was 36.3 kg/m(2) or 4.3 z-scores (2.9-5.9). BMI z-score decreased to 1.7 at the end of treatment and went back to 2.8 (0.8-6.1) 2 y after treatment. This corresponded to a weight loss of 30.3 kg and weight regain of 21.3 kg. After treatment, energy intake increased and physical activity decreased. The contribution of energy ingested at breakfast decreased while snacking increased. For all measurements, no dietary group differences existed at baseline or at any time during the intervention and follow-up. CONCLUSION: A higher protein content of the diet did not confer any benefit in the treatment of childhood obesity. Substantial weight loss was obtained with a moderately energy-restricted diet and normal fat content. After weight loss, mean weight increased in spite of moderate energy intake, together with a drift towards obesity-associated behavioural patterns. The causes of the inability to adopt normal weight subjects' behaviour permanently deserve to be investigated further.

[Detection of cortical activities on eye movement using functional magnetic resonance imaging].

Cortical activity during eye movement was examined with functional magnetic resonance imaging. Horizontal saccadic eye movements and smooth pursuit eye movements were elicited in normal subjects. Activity in the frontal eye field was found during both saccadic and smooth pursuit eye movements at the posterior margin of the middle frontal gyrus and in parts of the precentral sulcus and precentral gyrus bordering the middle frontal gyrus (Brodmann's areas 8, 6, and 9). In addition, activity in the parietal eye field was found in the deep, upper margin of the angular gyrus and of the supramarginal gyrus (Brodmann's areas 39 and 40) during saccadic eye movement. Activity of V5 was found at the intersection of the ascending limb of the inferior temporal sulcus and the lateral occipital sulcus during smooth pursuit eye movement. Our results suggest that functional magnetic resonance imaging is useful for detecting cortical activity during eye movement.

MR imaging of acoustic neuroma with high resolution fast spin echo T2-weighted sequence.

OBJECTIVE: To assess the value of high resolution 2D fast spin echo T2-weighted sequence (HR 2D-FSE T2w) for evaluating the internal auditory meatus (IAM) in patients with asymetric or unilateral sensorineural hearing loss, vs. gadolinium-enhanced T1-weighted (T1w) sequence; to suggest a screening protocol to exclude the diagnosis of acoustic neuroma in a patient with isolated unilateral sensorineural hearing loss. MATERIALS AND METHODS: One-hundred ten patients with suspected acoustic neuroma were evaluated with 1.5 T MRI system. The protocol included axial images focused on the IAM: HR 2D-FSE T2w images (4000/63, ETL = 16, 3-mm sections with 1.5 mm overlap, 18 FOV, 512 x 384 matrix) and gadolinium-enhanced T1w images (600/23, 3-mm sections, 18 FOV, 256 x 192 matrix). Two criteria for normality of the HR 2D-FSE T2w examination are defined: high homogeneous signal of the cerebellospinal fluid (CSF) and linear low signal of the nerves visible throughout the IAM. RESULTS: Overall results show no false-negative and six false-positive with HR 2D-FSE T2w sequences vs. gadolinium-enhanced T1w sequences. The sensitivity of HR 2D-FSE T2w sequences is 100%, specificity 93%, and negative preditive value 100%: normal images using HR 2D-FSE T2w sequence can rule out the diagnosis of acoustic neuroma. CONCLUSION: Using this protocol we can exclude the diagnosis of acoustic neuroma in case of normal HR 2D-FSE images and no additional gadolinium-enhanced T1w sequence is necessary. This protocol might reduce examination time, must promote recourse to MRI in the event of clinical suspicion of acoustic neuroma, and also enables savings by proposing MRI examination as a first-line exam.

[Toxic aluminum encephalopathy. Predominant involvement of the limbic system on MRI]. / Encéphalopathie toxique à l'aluminium. Atteinte prédominante du système limbique en IRM.

Two patients underwent acoustic schwannoma surgery by transmastoid approach. Petrous bone defect was filled in with aluminium-containing bone cement (Ionocem). A pseudomeningocele by CSF accumulation in subcutaneous temporoparietal area appeared after the procedure and, in subsequent weeks, encephalopathy with confusion and seizures. MRI showed cerebral involvement with herpes-like disposition. Temporal stereotactic biopsy in a case did not confirm viral encephalitis but disclosed cellular accumulation of lipofucsin and particles highly suggestive of aluminum-inclusions. Aluminium's levels in blood and CSF of both patients were very high and confirm the brain's toxic involvement. Aluminium's toxicity would be advocated in patients with neurologic disorders who have undergone maxillofacial or skull bone-cementoplasty by an aluminum-containing biomaterial, if this cement is in contact with CSF.

Activation of the hippocampal formation by vestibular stimulation: a functional magnetic resonance imaging study.

Functional MRI (f-MRI) is a non-invasive technique developed to permit functional mapping of the brain with a better temporal and spatial resolution than that offered by PET techniques. In our study, f-MRI was performed using blood oxygenation level dependent (BOLD) contrast imaging based on the magnetic properties of hemoglobin. This method relies on changes in the blood supply to the brain that accompany sensory stimulation or changes in cognitive state. All the images were obtained at 1.5 T on a Signa GEMS without ultrafast imaging. The vestibular stimulation was cold irrigation of the external auditory meatus (caloric stimulation). A population of normal healthy volunteers without a history of vestibular dysfunction was studied. The hippocampal formation as well as the retrosplenial cortex and the subiculum were activated by vestibular stimulation, suggesting that this activation may be related to spatial disorientation and a sensation of self-rotation experienced by the subjects during vestibular stimulation. The other results are similar to those obtained using PET.

[MRI and Listeria monocytogenes rhombencephalitis]. / IRM et rhombencéphalites a Listeria monocytogenes.

Rhombencephalitidis is a serious form of brainstem inflammation, difficult to diagnose on the basis of clinical and laboratory findings alone. We describe the MR appearance of 3 cases of Listeria monocytogenes rhombencephalitidis and correlate the findings with clinical information. MR imaging is crucial for early diagnosis of this illness: patchy signal hyperintensity throughout the medulla and cerebellar peduncles on T2 weighted images, always in association with a hypointense dot; numerous gadolinium-enhanced microabcesses in the rhombencephalon. MR imaging is very useful for follow-up examinations.

[Spinal osteoid osteoma, neuralgia and MRI]. / Ostéome ostéoïde rachidien, radiculalgie et IRM.

Computed Tomography (CT) is the most valuable imaging modality for the diagnosis of osteoid osteoma. Magnetic Resonance Imaging (MRI) is less performant than CT. However, in case of neuralgia a disk disease is searched for and MRI is often performed at first. The authors report 2 cases of MRI diagnosis of osteoid osteomas histologically proved. The presence of bone marrow and soft tissues changes consistent with inflammation adjacent to the nidus is the main sign. Inflammatory changes are characterized by low signal on T1-weighted sequence, high signal on T2 and enhancement after gadolinium IV administration. These changes are not specific. But in these 2 cases, an osseous abnormality was detected and the nidus was suspected even if MRI was less conspicuous than CT. In case of children or young adults with radiculalgia and normal disk, inflammatory localized changes in MRI must be suspicious of the diagnosis of osteoid osteoma.

[A rare case of chondroid chordoma of the cervical spine]. / Un cas rare de chordome chondroïde du rachis cervical.

Chordoma is a rare tumor in spine. Authors report the case of a 49 years old woman suffering from C5 left neuralgia. Plain films showed an enlargement of C4-C5 left foramina. CT scan permitted to see a lobulated tumor with low density just a few enhancement into septa. MRI showed the tumor with low signal on T1wi, high signal on T2wi and slight enhancement after Gadolinium administration. The extension in the vertebral body is very limited. Differential diagnosis are chondroma or chondrosarcoma and epidermoid cyst. Histology with evidence of a chondroid matrix explain the CT and MR appearance. In this localisation, there is no case reported in the litterature. This is an outstanding case because its extra-osseous localization with a lack of contrast enhancement after injection and its unusual histologic pattern.

[Neurinoma of the intrapetrous facial nerve (apropos of 5 cases)]. / Les neurinomes du nerf facial intrapétreux (à propos de 5 cas).

Five patients with intra-petrous facial neuromas were treated between 1993 and 1995. The most common symptom was facial paralysis in four cases and conduction hearing loss with a mass behind the tympanic membrane in one case. For all cases a MRI led to an accurate diagnosis of the tumoral invasion. Four patients had an operation (one middle cranial fossa approach, one transmastoidal approach and two transmastoidal approach and middle cranial fossa approach associated). Results are analysed and a discussion on the clinical and para-clinical diagnosis as well as the treatment method is realized considering the literature.

[Magnetic resonance imaging and meningiomas of the posterior cerebral fossa. 31 cases]. / Imagerie par résonance magnétique et méningiomes de la fosse cérébrale postérieure. 31 cas.

To assess the value of MRI for meningioma of the posterior cerebral fossa, in correlation with surgical and pathological findings, we retrospectively reviewed 31 cases. The patients (24 females and 6 males ranging in age from 25 to 79 years) were preoperatively studies on a 1,5 T MR imager (GEMS Signa) between july 1989 and november 1993. The protocol included: 1. MR scan with axial sections in T2-weighted spin-echo sequence (3 mm thickness), T1-weighted spin-echo sequence before and after gadolinium injection (3-5 mm thickness), coronal and sagittal T1-weighted sections performed after injection. 2. Surgery reports. 3. Histopathological reports; the predominant histological subtype of each tumor was graded according to the classification scheme of Russel and Rubinstein. We focused on five items: 1. The site of the dural attachment of the meningioma. 2. Tumoral extensions (to the tentorium, to the jugular foramen, to the internal auditory canal). 3. The meningioma signal in T1- and T2-weighted sequence using the same visual scoring system for grading signal intensities as Elster and al. 4. Secondary features (necrosis, cysts, calcifications) within the tumor. 5. Interface between meningioma and encephalic structures. Meningiomas arose from the posterior surface of the petrous bone in 74% of the cases and from the clivus in 9.6%. Meningiomas were bulky at the time of diagnosis as since tumoral arrow overtook 2 cm in 64.5% of the cases. Surgical approach was guided by an anatomo-radiologic classification based on the exact site of tumoral dural attachment. This determination relied on: 1. Osseous reaction noted in 58% of the cases (enostosic spur in 19%, localized osseous thickening in 16%). 2. The trigeminal nerve displacement by the tumor; in case of clival meningioma extended to the petrous apex, this nerve is displaced outside; otherwise, meningioma of the petrous bone extended to the clivus displaced the trigeminal nerve inside. 3. Radiate structure within tumor converging to vascular basal pole of the meningioma noted in 42% of the cases. Tentorial involvement remained a difficult diagnosis on MR images. It was affirmed when the tumor extended on the opposing surface of the tentorium and when focal hypersignal existed through the usual tentorial hyposignal on T2-weighted images and T1-weighted images after gadolinium. On the other hand, tentorial linear dural enhancement adjacent to the tumor was not a reliable sign (error in 15.8% of the predicted cases). The meningothelial (syncitial) type was noted in 67.7% of the cases. (ABSTRACT TRUNCATED AT 450 WORDS)

[MRI aspects of progressive multifocal leukoencephalopathy]. / Aspects IRM de la leucoencéphalopathie multifocale progressive.

Progressive Multifocal Leukoencephalopathy is a demyelinating disease. MRI shows high signal intensity areas on T2w sequence and low intensity aeras on T1w sequence, without enhancement after intravenous contrast injection. The involvement of arcuate fiber (U fibers) creates a sharp border with the cortex. There is no mass effect. Involvement of parieto-occipital areas is frequent. The lesions may be uni or bilateral, single or multiple; bilateral lesions are asymmetric. This typical appearance on MR images occurs in 90% of the patients with PML. Some atypical patterns may occur: focal hemorrhage, atrophy, faint peripheral enhancement and involvement of deep gray matter (basal ganglia). In most cases, the clinical and MR features provide the diagnosis. The main differential diagnosis, in MRI, is HIV-leukoencephalitis, but lesions are diffuse, less intense on T2w sequence and not visible on T1, without involvement of the arcuate fibers. Stereotactic biopsy should be performed only for atypical lesions, particularly in case of predominant involvement of deep gray structures.

[Dental-radicular cysts invading the maxillary sinus]. / Kystes radiculodentaires à expression sinusienne.

The authors report three cases of radicular cyst developing into the maxillary sinus which was partially or completely obscured. Looking for a thin rim of cortical bone should be undertaken in case of opacity of maxillary sinus. This rim correspond to the floor of the sinus, which is lifted up by the cyst. If the attenuation value of the intrasinusal process is near of that of water, the diagnosis of radicular cyst invading the maxillary sinus is very likely and may indicate intraoral surgical approach.

[Rhabdomyolysis and truncular sciatica. 2 cases studied by MRI]. / Rhabdomyolyse et sciatique tronculaire. Deux cas étudiés en IRM.

We report two cases of acute rhabdomyolysis in pelvic girdle muscles with sciatic palsy secondary to compression of the sciatic nerve trunk, with clinical and MRI correlation. The diagnosis of rhabdomyolysis is based on clinical and biological data, but diagnosis of compression complications secondary to swelling of the muscles, especially the compression of nerve trunk, is done by imaging. T2 weighted images give a definite anatomical evaluation. They show enlarged high signal intensity muscles and anatomic relationship with the sciatic nerve from its emergence out of pelvis, giving a good correlation between rhabdomyolysis and the compressed nervous trunk. It helps for planning a possible surgical fasciotomy. However, MRI provides only morphological informations, but not differentiates edema from necrosis in involved muscles.

[MRI of the operated lumbar spine and enhancement of intradural nerve roots. 478 cases]. / IRM du rachis lombaire opéré et rehaussement des racines intradurales. 478 cas.

Authors report a study of 478 MR imaging in failed back surgery syndrome. Enhancing nerve roots were detected in 73.8%, with a significant higher percentage in male patients, and long postoperative delay. There was no significant correlation with age, enhancement of epidural scar (epidural scar was seen in 75.7%) and disk herniation (seen in 25.9%). Alteration of blood-nerve-barrier causes enhancement, but the mecanism is nuclear: mechanical, biological, immunological or Wallerian degeneration. Diagnostic and prognostic value of enhancement are not proven and a study of asymptomatic patients is necessary.

[MRI of the internal auditory meatus. Is injection of gadolinium indispensable?]. / IRM du méat auditif interne. L'injection de gadolinium est-elle indispensable?

OBJECT: To compare prospectively high resolution fast spin echo T2 weighted (FSE-T2W) images and gadolinium-enhanced spin echo T1 weighted images for diagnosis of pathology of the internal auditory meatus (IAM). PATIENTS AND METHODS: 114 patients underwent MR imaging at 1.5 T with the following protocol: axial images; whole brain FSE-T2W sequence (256 matrix); 2 sequences focused on IAM with high resolution FSE-T2W acquisitions (512 matrix, 3 mm sections with 1.5 mm overlapping); pre and postcontrast T1 weighted sequences focused on IAM. Examinations were viewed by senior neuroradiologists. RESULTS: 31 lesions were detected in the IAM by high resolution FSE-T2W images; 25 lesions were found in the IAM by postcontrast T1 weighted images, i.e. 6 false-positive results and none false-negative. On the basis of 228 studied IAMs the sensitivity, specificity and negative predictive value of this high resolution FSE-T2W sequence were 100%, 97% and 100% respectively. CONCLUSION: Gadolinium enhanced sequence is not indispensable if high resolution FSE-T2W images are normal. Gadolinium-enhanced sequence remains essential in others equivocal cases (difficult diagnosis or abnormal IAM).

[Diffuse toxoplasmic encephalitis in a non-immunosuppressed patient]. / Encéphalite toxoplasmique diffuse chez un sujet non immunodéprimé.

Diffuse encephalitic toxoplasmosis is an unusual presentation of toxoplasmosis, in which neuroradiological investigations may not show focal abcesses. Until now it was only reported in immunocompromised patients. In immunocompetent patients, cerebral toxoplasmosis is very unusual, and appears as multiple abcesses, like the classic form in immunocompromised patients. We report the case of an immunocompetent patient who presented a diffuse encephalitic toxoplasmosis; CT and MR examinations showed only nonspecific features of brain swelling and cortical infarct due to vasculitis.

[Myxoid liposarcoma. MRI imaging]. / Liposarcome myxoïde. Aspects en IRM.

PURPOSE: Myxoid liposarcoma is the most common type of liposarcoma (approximately 40 to 50% of all liposarcomas). The main tissue component is a myxoid matrix present primarily in extracellular compartments; proliferating lipoblasts account for less 10% of the tumor: MRI appearances are not typical for lipomatous tumor. Nevertheless histological features may permit understanding MRI findings and identifying patients with myxoid liposarcoma. MATERIALS AND METHODS: Clinical history and radiologic images of 7 patients with histologically verified myxoid liposarcoma were retrospectively studied. In all patients the tumor presented in a lower extremity as a painless, slowly growing mass. MR images were available for review in all cases (T1- and T2-weighted images); in addition fat-suppression before and after gadolinium enhancement were assessed with T1-weighted sequences. RESULTS: MRI examination revealed an "encapsulated" tumor, non infiltrating and septated. On T1-weighted sequences all the lesions show lacy, amorphous and linear foci of high signal within a low signal of the tumor due to the predominance of a myxoid matrix. The high sensitivity of MRI demonstrates the presence of small areas of high signal and fat-suppression technique is valuable for characterizing soft-tissue tumors: suppression of high signal intensity on fat-saturated T1-weighted images indicates the presence of fatty tissue components. CONCLUSION: Clinical correlation with MRI appearances on T1-weighted sequences (in addition to fat-suppression technique) may suggest the possibility of myxoid liposarcoma.

[Bilateral adrenal hemorrhage induced by stress. Radiological diagnosis. Apropos of a case]. / Hémorragie surrénalienne bilatérale par stress. Diagnostic radiologique. A propos d'une observation.

Bilateral hemorrhage of the adrenal gland is a rare disease in adults. Although stress is often said to be the cause, it is rarely observed. The non specific clinical manifestations, and the absence of adrenal insufficiency demonstrate the importance of radiology. The diagnosis is made by ultrasonography and CT scan, which reveals an oval adrenal mass of high density that subsequently decreases in both size and density.