High frequency of creatine deficiency syndromes in patients with unexplained mental retardation.
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Adolescent↗
Biomedical subjects
F Cotton
Publications and source records attributed to F Cotton.
Functional anatomy of the therapeutic effects of prism adaptation on left neglect.
OBJECTIVE: To investigate the anatomic substrates underlying the beneficial effect of prism adaptation in five patients with persistent left neglect following right stroke. METHODS: In a functional imaging PET study, we used a covariation analysis to examine linear changes of regional cerebral blood flow over sessions as a function of left neglect improvement. RESULTS: The network of significant brain regions associated with improvement of left neglect performance produced by prism adaptation involved the right cerebellum, the left thalamus, the left temporo-occipital cortex, the left medial temporal cortex, and the right posterior parietal cortex. CONCLUSION: Our results suggest that the realignment of visuomotor coordinates is processed by the cerebellum and that low level sensorimotor adaptation actively modulates cerebral areas, albeit now relying on intact cerebellocerebral connections. Hence, our data support the hypothesis that the beneficial effect of prism adaptation on the clinical presentation of left neglect derives from modulation of cortical regions implicated in spatial cognition.
Adaptation, Physiological↗
MRI evaluation of bulky tumor masses in the mesentery and bladder involvement in peritoneal carcinomatosis.
AIM: Peritonectomy procedures with intraperitoneal chemohyperthermia are an effective but costly treatment for peritoneal carcinomatosis (PC). Consequently a proper selection of patients is necessary. We evaluated the benefit of MRI prior to surgery, in the detection of two of the main surgery contraindications: bulky mesenteric tumors and bladder implants. METHODS: Three experts retrospectively reviewed abdominal and pelvic MRI from 19 cases of surgically proved PC (ovary: 7; colorectal: 7; gastric: 2; pseudomyxoma peritonei: 2; appendix: 1). RESULTS: Mesenteric tumors were always identified as hypersignal masses on axial and coronal fat suppression gadolinium-enhanced T1 images (n=3). Three out of five bladder implants were detected. The two cases of bladder implants that were not detected on MRI were missed because the bladder was not filled. The best sequence for the detection of bladder involvement was axial T2-weighted images with bladder filling. CONCLUSIONS: Evaluating the preoperative resectability of PC is crucial for patient management. MRI seems to reliably detect bulky mesenteric tumors and bladder implants on condition the bladder is filled and appropriate sequences are used.
Carcinoma↗
Functional morphology of phonation evaluated by dynamic MRI.
The complex anatomy of the larynx is a consequence of its various airway functions. The aim of the present study was to evaluate which anatomical structures of the larynx soft tissues could be defined using MRI, and to investigate the feasibility of using this technique to assess the dynamic functions of the larynx. MRI images of the larynx of six healthy volunteers during speech production were obtained in vivo. The volunteers were asked to breathe out long and deep in order to prolong in a normal voice the emission of the vowels [i] (as in key) and [a] (as in car) and the consonant [ch] (as in ship). We demonstrated the modification of the larynx position, which is high for [i] and low for [a], and the modification of the vocal folds which is adducted and abducted in [i] and kept abducted in [ch]. Dynamic MRI allows the possibility of multiplanar high-resolution imaging. It can provide information about the anatomy of the larynx and, it also has the ability to image moving laryngeal structures and to analyze vocal fold vibrations during phonation.
Adult↗
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.
Adolescent↗
[Diffusion and perfusion MR imaging in cerebral lymphomas].
Because of the increasing incidence of cerebral lymphoma, it is critical for patient management to recognize the MR features of this disease. We present the characteristic morphological and functional MRI features of this tumor. The findings on MRI studies, including morphological, diffusion and perfusion imaging, performed in 9 biopsy-proven cases of cerebral lymphoma with 13 lesions are presented and analyzed, and are discussed in comparison with published literature data. All patients underwent diffusion-weighted imaging with a single shot echo-planar pulse sequence. Dynamic susceptibility-contrast MRI was performed using a T2*-weighted gradient-echo echo-planar sequence after intravenous injection of chelates of gadolinium at the rate of 6 ml/s and a temporal resolution of 1 second. All cases of cerebral lymphoma appeared hypointense or isointense on T1-weighted images and in 75% of cases iso- or hypointense on T2-weighted images. All lesions enhanced except one in a patient receiving steroid therapy. On diffusion-weighted images, tumours were hyperintense with normal or decreased ADC values (0.717+/-0.152.10-3 mm2/sec, range: 0.550-1.014) and an ADC ratio tumour/normal white matter of 0.974+/-0.190 (range: 0.768-1.410). On perfusion, the signal intensity-time curve of each tumour showed a characteristic type of curve with a significant increase of the signal intensity above the baseline and a low maximum relative cerebral blood volume ratio (rCVBmax) of 1.43+/-0.64 (0.55-2.62). Due to their higher cellularity, the lack of neoangiogenesis, and the increased permeability of the blood-brain barrier related to the infiltration of blood vessels wall by lymphomatous cells, cerebral lymphoma presents characteristic diffusion and perfusion MRI features that should be useful for diagnosis and patient follow-up.
Adult↗
Advanced MRI could help to differentiate meningeal carcinomatosis with mass effect from cerebral metastasis in prostate cancer.
Prostatic neoplasms are the second cause of mortality due to cancer in men. Brain metastases are a rare presentation, whereas epidural localizations are relatively frequent. However both occur late in the evolution of the cancer. Thus a reliable, fast and non-invasive diagnosis would be useful in this setting. Regarding the prognosis of such disease, earlier treatment may probably influence the quality of life and postpone fatal evolution. However improved survival is more hypothetical. We report the case of a 69-year old man with a hormone refractory adenocarcinomatous prostatic cancer presenting with diffuse intracranial metastases. An MRI analysis using T2 perfusion images, diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps excluded intra-axial brain metastases and concluded to the existence of voluminous nodular dural metastases. We discuss the imaging techniques and review literature of neurological complications of prostate cancer.
Carcinoma↗
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.
Acute Disease↗
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.
Adult↗
Optic ataxia errors depend on remapped, not viewed, target location.
Optic ataxia is a disorder associated with posterior parietal lobe lesions, in which visually guided reaching errors typically occur for peripheral targets. It has been assumed that these errors are related to a faulty sensorimotor transformation of inputs from the 'ataxic visual field'. However, we show here that the errors observed in the contralesional field in optic ataxia depend on a dynamic gaze-centered internal representation of reach space.
Adult↗
[Correlation between cranial vault size and brain size over time: preliminary MRI evaluation].
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.
Adult↗
Clinical Vignette. Sciatic nerve entrapment secondary to heterotopic ossification: imaging findings and potential effect of selective cox-2 inhibitors.
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Adult↗
[Sickle cell disease: exotic disease or a Belgian public health problem?].
Sickle cell disease is a genetic disorder involving the haemoglobin designated as haemoglobin S, an autosomic recessive hereditary disease. It is the most frequent hereditary disease in sub-Saharan Africa, however epidemiological studies performed with a systematic neonatal screening in Brussels and Liège have proven that more than one neonate over 2.000 has a sickle cell disease. If this amount is significant, at the level of each physician the number of patient-contacts will be weak. Another aspect of the disease is the variability in its expression: some patients suffer from multiple and chronic organ alterations while other suffer also from acute events which might lead to death if not treated appropriately. The poor experience of each physician, the lack of the disease knowledge by the population, the symptoms complexity, and the socio-economical aspects of sickle cell disease explain that it can be considered as an "exotic" disease but also as a public health problem. A global and dedicated approach of the patient as a whole must be implemented. This is the reason for the existence of the "Réseau des Hémoglobinopathies": http://www.redcellnet.be/.
Africa↗
Effect of stimulus frequency and stimulation site on the N1m response of the human auditory cortex.
The aim of the present study was to investigate the functional organization of the auditory cortex for pure tones of 1, 2, 4, 6, 8 and 12 kHz. Ten subjects were tested with a whole-head magnetometer (151 channels). The location, latency and amplitude of the generators of the N1m (the main component of the response, peaking approximately at 100 ms) were explored simultaneously in the right and left hemispheres under monaural stimulation. Our results revealed that tonotopy is a rather complex functional organization of the auditory cortex. From 1 to 12 kHz, tonotopic maps were found for contralateral as well as for ipsilateral stimulation: N1m generators were found to be tonotopically organized mainly in an anterior-posterior direction in both hemispheres, whatever the stimulated ear, but also in an inferior-superior direction in the right hemisphere. Furthermore, latencies were longer in the left than in the right hemisphere. Two different representations of spectral distribution were found in the right auditory cortex: one for ipsilateral and one for contralateral stimulation.
Acoustic Stimulation↗
[MRI of central nervous system in a series of 58 systemic lupus erythematosus (SLE) patients with or without overt neuropsychiatric manifestations].
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.
Adult↗
Transpedicular screwing of the seventh cervical vertebra: anatomical considerations and surgical technique.
The purpose of this study was first to assess the feasibility of C7 transpedicular screwing with a morphological study and secondly to evaluate the safety of such a surgical technique when guided only by posterior landmarks. Eighteen C7 vertebrae, harvested from fresh human cadavers, were included in this study. First the morphometry of C7 pedicle was performed on computed tomography with multiplanar reconstructions. Results of this quantitative anatomy were compared with the literature data. Secondly 30 pedicle screws, whose placement was guided only by anatomical features on the posterior face of the dorsal arch, were inserted in 15 C7 vertebrae. A second computed tomographic examination was done after the surgical procedure to check the screw placement in both planes. The average pedicular width was 6+/-1.2 mm and the average height was 5.8+/-1.1 mm. The pedicle angulation in the transverse plane was 33.3 degrees +/-6.6 degrees, the pedicle angulation in the sagittal plane was 4.3 degrees +/-4.5 degrees downward with reference to the lower endplate of C7. The average distance from the entry point of transpedicular screwing to the anterior cortex of the vertebral body was 29+/-3 mm. Concerning the safety of transpedicular screwing, 63% of screws were found entirely inside the pedicle without any violation of the pedicle cortex. Most of pedicle violations were observed in the transverse plane. No grade II violation of the pedicle was observed. Dimensions of the C7 pedicle are amply compatible with transpedicular fixation using 3.5 mm screws. Such a surgical technique seems to be an interesting option when posterior fixation of C7 is required. Nevertheless morphological guidelines appeared not to be sufficient to ensure safe transpedicular screwing. Laminoforaminotomy is strongly recommended, although it has not been evaluated in this study.
Aged↗
[The maxillary sinus: evolution and function in aging].
The maxillary sinus, or Highmore's antrum, is located in the maxillary bone. The maxillary, above the buccal cavity, below the orbital cavity and outside the nasal fossa, is going to take a part in the formation of the three cavities which surround it. Although voluminous, it is consists of a light bone. This distinctive feature is essentially due to the fact that the maxillary has a cavity. The maxillary sinus occupies the upper 2/3s of this maxillary bone. It is the largest of the facial structure's cavities. Its volume is very variable, depending on the individual, the condition of their edentulousness and their age. We find small, average or large sinuses. This sinus communicates with the corresponding nasal fossa by a canal. It opens at the level of the nasofrontalis duct by a meatic ostium, an ostium located at the top of the meatus nasi medius, i.e. under the floor of the sinus. This highly positioned drainage location easily explains the problems that sinus pathologies can come up against. The sinus is lined with a mucous membrane and we can point out that in the normal condition this mucous membrane adheres weakly to the bone. It is more or less thick as a function of the pathologies to which the sinus has been subjected, or even as a function of the geographical location where the individual lives. The imaging of this sinus as a function of age is not obvious due to the fact that it is invisible throughout embryonic and foetal development, and that it only becomes visible to X-rays relatively late, at about 6 years old. Its role is important at the level of the growth of the facial structure because it is always easier to have growth around cavities. It also has a mechanical role concerning the transmission of shockwaves during traumas. In old individuals, due to the condition of the edentulousness, the volume of the sinus is larger; in fact one can note the resorption of the alveolar bone. The maxillary sinus is a cavity which plays a very important role throughout an individual's existence because of the previously mentioned reasons, and which could be used during surgical reconstructions, by the partial filling of this space, to increase the quantity of usable bone (grafts...).
Adolescent↗
The delayed perfusion sign at MRI.
PURPOSE: Effective collateral blood flow seem to be an important factor associated with a small infarct volume and a good clinical outcome. We aimed to assess leptomeningeal collateral blood flow on source perfusion-weighted images in patients with acute stroke. MATERIALS AND METHODS: 29 patients with proximal middle cerebral artery occlusion (MCA alone, n=17; MCA + internal carotid artery [ICA] occlusion, n=12) were evaluated with MRI at baseline before thrombolytic therapy, and at day 60. Clinical evaluation was performed at days 0 and 60 with the National Institutes of Health Stroke Scale (NIHSS) score, and at day 60 with the modified Rankin score. We assessed (on source images of the dynamic contrast-enhanced T2*-weighted perfusion [PWI] sequence) the presence of a hypointensity consistent with delayed contrast arrival within the global perfusion deficit (delayed perfusion sign). We analyzed the extent of the area demonstrating such delayed perfusion (DP area) on source images of the PWI sequence, and compared it with the global perfusion (GP) abnormality shown by time-to-peak maps. We calculated the Spearman rank correlation coefficient between the DP/GP ratio and: 1. age; 2. clinical scores; 3. site of occlusion [MCA alone versus ICA+MCA occlusion]; 4. DWI lesion size at day 0, and T2WI lesion size at day 60; 5. PWI-derived parameters (time-to-peak [TTP], relative cerebral blood volume [rCBV], relative cerebral blood flow [rCBF], and peak height). All tests were bilateral and a p value<0.05 was considered as significant. RESULTS: Delayed perfusion areas of various size were found within the global perfusion deficit in all patients. High DP/GP ratio values were significantly correlated with: 1. better clinical scores at day 0 and day 60 (all p<=0.04); 2. smaller lesions at day 0 DWI and at day 60 T2WI (all p<=0.004); 3. ICA patency (r=0.49, p=0.01); 4. lower TTP delays, and higher values of rCBV, rCBF, and peak height. CONCLUSION: These preliminary data suggest that a delayed contrast filling observed on native perfusion-weighted images may be a marker of leptomeningeal collateral blood flow, and may lead to better clinical and morphological outcomes in acute ischemic stroke.
Acute Disease↗