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Biomedical subjects

I Berry

Publications and source records attributed to I Berry.

At least 19 recordsLinked to original sources
PubMed2006

Defective efficacy of retinoic acid treatment in patients with metastatic thyroid carcinoma.

Radioiodine (I-131) therapy is of proven efficacy for differentiated thyroid carcinoma. However, its efficacy relies on specific uptake mechanisms, which may be lost during the evolution of the disease. Attempts to increase the iodine uptake of such tumors have been made using retinoic acid because it exerts redifferentiating effects on thyrocytes. This study aims to assess the capability of the retinoic acid (RA) treatment to reinforce iodine 131-irradiation efficacy for metastatic and progressive multi-irradiated thyroid cancer. In this clinical prospective study, 11 patients (mean age +/- 1 SD = 61 +/- 12 years, sex ratio M/F = 5/6) with a progressive disease despite iterative surgery and iodine irradiations were treated with 13-cis-retinoic acid (1.5 mg/kg day) over 8 weeks prior to I-131 irradiation. The redifferentiating effect of RA was evaluated by serum thyroglobulin (Tg) monitoring during RA treatment and qualitative analysis of iodine uptake on the post-therapeutic whole body scan. The clinical usefulness of RA treatment was assessed by clinical follow-up, Tg monitoring, and tumor size. No serious event that could possibly be related to the treatment was reported. The mean follow up time was 24.2 +/- 12 months (range 3-46 months). Iodine uptake was only slightly improved in two patients. Nevertheless, the clinical benefits of RA seem to be very poor. Five patients died of a metastatic disease. Five others presented new clinical evidences of a progressive disease. In conclusion, this prospective study demonstrates the absence of efficacy of I-131 irradiation combined with RA for the treatment of patients with aggressive, rapidly growing metastatic thyroid cancer. Thus, patients with highly aggressive disease, rapidly growing in a short period from 2 to 6 months, should not be considered for RA therapy.

Adult↗
PubMed2006

Iodine-131 pharmacokinetics in patients on hemodialysis for end stage renal disease: clinical implications.

AIM: Curative treatment of thyroid cancer is a major issue for patients with end stage renal disease (ESRD) undergoing dialysis because they might not be included in a renal transplant protocol once they have overcome this disease. Since 131I is mostly eliminated by the kidneys, there is concern regarding the toxicity, efficacy and feasibility of 131I-therapy of anuric dialyzed patients. METHODS: This paper reports on 131I uptake and elimination from remnant thyroid tissue (T), salivary glands (SG), stomach (S) and blood, after administration of 3.7 GBq of 131I for 2 patients on twice weekly dialysis for ESRD. RESULTS: Compared to normal renal function patients, radio-iodine recirculation is observed, and SG and blood irradiation is about 6 times higher, but the dose delivered to the thyroid is not significantly enhanced. Dialysis removes more 131I from SG, S and blood than from T. Anticipated dialysis will reduce irradiation by 38% for the blood, 45% for SG and 34% for T. CONCLUSIONS: Therefore, a higher 131I amount could then be used, providing that accurate personalized dosimetry is previously performed using 131I pharmacokinetic models. Concerning radiation protection issues, no significant dialysis equipment contamination is noted, and nurses and medical staff exposure remains below 0.2 mSv.

Adult↗
PubMed2003

Clinical-MRI correlations in the secondary progressive phase of MS: lessons from the treatment trials.

Conventional MRI techniques are sensitive to detect MS lesions and their change overtime. In relapsing-remitting MS correlations with clinical measures are weak suggesting a pathological heterogeneity of these lesions. There are less data available in secondary progressive phase of the disease. The best source for clinical MRI correlations analysis is the placebo arm of the published interferon beta trials. This review presents the main clinical-MRI findings from these trials then focuses on recent promising observations obtained with non conventional MRI techniques in SP MS patients.

Clinical Trials as Topic↗
PubMed2003

Deep brain stimulation for parkinson's disease: correlation between intraoperative subthalamic nucleus neurophysiology and most effective contacts.

Though intraoperative neurophysiology is essential to precisely define the definitive target, little is known regarding its predictive value in defining the most effective contact for chronic deep brain stimulation. In this retrospective study, we reviewed the correlation between intraoperative neurophysiology and contacts selected for chronic stimulation. Twenty consecutive patients implanted for subthalamic nucleus (STN) stimulation were reviewed. There was no significant correlation between the electrophysiologically defined STN and the most effective contact for chronic stimulation at 3 months or at 6 months. Furthermore, there was a discrepancy between the most effective contact for rigidity versus akinesia or tremor at 3 months. Interestingly, at 3 months, the same electrode contact was maximally efficient for rigidity, akinesia and tremor in only 13 of the 39 cases. This lack of correlation did not affect the global improvement.

Adult↗
PubMed2001

Chronic motor cortex stimulation for phantom limb pain: a functional magnetic resonance imaging study: technical case report.

OBJECTIVE AND IMPORTANCE: Chronic motor cortex stimulation has provided satisfactory control of pain in patients with central or neuropathic trigeminal pain. We used this technique in a patient who experienced phantom limb pain. Functional magnetic resonance imaging (fMRI) was used to guide electrode placement and to assist in understanding the control mechanisms involved in phantom limb pain. CLINICAL PRESENTATION: A 45-year-old man whose right arm had been amputated 2 years previously experienced phantom limb pain and phantom limb phenomena, described as the apparent possibility of moving the amputated hand voluntarily. He was treated with chronic motor cortex stimulation. INTERVENTION: Data from fMRI were used pre- and postoperatively to detect shoulder and stump cortical activated areas and the "virtual" amputated hand cortical area. These sites of preoperative fMRI activation were integrated in an infrared-based frameless stereotactic device for surgical planning. Phantom limb virtual finger movement caused contralateral primary motor cortex activation. Satisfactory pain control was obtained; a 70% reduction in the phantom limb pain was achieved on a visual analog scale. Postoperatively and under chronic stimulation, inhibiting effects on the primary sensorimotor cortex as well as on the contralateral primary motor and sensitive cortices were detected by fMRI studies. CONCLUSION: Chronic motor cortex stimulation can be used to relieve phantom limb pain and phantom limb phenomena. Integrated by an infrared-based frameless stereotactic device, fMRI data are useful in assisting the neurosurgeon in electrode placement for this indication. Pain control mechanisms and cortical reorganization phenomena can be studied by the use of fMRI.

Electric Stimulation Therapy↗
PubMed2001

Virtual movements activate primary sensorimotor areas in amputees: report of three cases.

OBJECTIVE: In our multidisciplinary pain clinic, three patients with amputated limbs and with surgical indications for chronic motor cortex stimulation for phantom limb pain were selected for their ability to voluntarily move the missing limb. The sensation of being able to move a missing limb at will occurs quite frequently among traumatic amputees, but the ability to control it sufficiently to perform a functional magnetic resonance imaging (fMRI) examination is more rarely encountered. We used motor fMRI to study these virtual movements. METHODS: In two patients with upper-limb amputations, movements of the stump, the normal hand, and the missing arm were studied. In a third patient with both legs amputated, movements of the stumps and of the missing feet were studied. The fMRI data were analyzed with the Statistical Parametric Map 96 software and reformatted for integration into anatomic slices. RESULTS: Virtual movements of the missing limbs produced contralateral primary sensorimotor cortex and central sulcus activations in the patients with upper-limb amputation. Interhemispheric and bilateral activations were found in the patient with both legs amputated. These activation areas were different from the stump activation areas. Additionally, the significance thresholds chosen to generate the activation maps in virtual movements (although individual) were globally the same as those used to detect motor activation in the normal side of the patients. CONCLUSION: Cortical areas devoted to the missing limb seem to persist for several years after amputation. The precentral activations found in our patients are in agreement with the statement that the neural mechanisms involved in the mental representation of an action and in its execution are the same. Data from fMRI can be used to evaluate phantom limb virtual movements and to study cortical reorganization phenomena that can appear with time or as a result of some therapies. In these patients, fMRI data may be useful in assisting the neurosurgeon in the placement of chronic motor cortex electrodes.

Adult↗
PubMed2001

Methodological and technical issues for integrating functional magnetic resonance imaging data in a neuronavigational system.

OBJECTIVE: The aim of this article was to analyze the technical and methodological issues resulting from the use of functional magnetic resonance image (fMRI) data in a frameless stereotactic device for brain tumor or pain surgery (chronic motor cortex stimulation). METHODS: A total of 32 candidates, 26 for brain tumor surgery and six chronic motor cortex stimulation, were studied by fMRI scanning (61 procedures) and intraoperative cortical brain mapping under general anesthesia. The fMRI data obtained were analyzed with the Statistical Parametric Mapping 99 software, with an initial analysis threshold corresponding to P < 0.001. Subsequently, the fMRI data were registered in a frameless stereotactic neuronavigational device and correlated to brain mapping. RESULTS: Correspondence between fMRI-activated areas and cortical mapping in primary motor areas was good in 28 patients (87%), although fMRI-activated areas were highly dependent on the choice of paradigms and analysis thresholds. Primary sensory- and secondary motor-activated areas were not correlated to cortical brain mapping. Functional mislocalization as a result of insufficient correction of the echo-planar distortion was identified in four patients (13%). Analysis thresholds (from P < 0.0001 to P < 10(-12)) more restrictive than the initial threshold (P < 0.001) had to be used in 25 of the 28 patients studied, so that fMRI motor data could be matched to cortical mapping spatial data. These analysis thresholds were not predictable preoperatively. Maximal tumor resection was accomplished in all patients with brain tumors. Chronic motor cortex electrode placement was successful in each patient (significant pain relief >50% on the visual analog pain scale). CONCLUSION: In brain tumor surgery, fMRI data are helpful in surgical planning and guiding intraoperative brain mapping. The registration of fMRI data in anatomic slices or in the frameless stereotactic neuronavigational device, however, remained a potential source of functional mislocalization. Electrode placement for chronic motor cortex stimulation is a good indication to use fMRI data registered in a neuronavigational system and could replace somatosensory evoked potentials in detection of the central sulcus.

Adolescent↗
PubMed2001

Perimetric visual field and functional MRI correlation: implications for image-guided surgery in occipital brain tumours.

OBJECTIVE: To compare the results of visual functional MRI with those of perimetric evaluation in patients with visual field defects and retrochiasmastic tumours and in normal subjects without visual field defect. The potential clinical usefulness of visual functional MRI data during resective surgery was evaluated in patients with occipital lobe tumours. METHODS: Eleven patients with various tumours and visual field defects and 12 normal subjects were studied by fMRI using bimonocular or monocular repetitive photic stimulation (8 Hz). The data obtained were analyzed with the statistical parametric maps software (p<10(-8)) and were compared with the results of Goldmann visual field perimetric evaluation. In patients with occipital brain tumours undergoing surgery, the functional data were registered in a frameless stereotactic device and the images fused into anatomical three standard planes and three dimensional reconstructions of the brain surface. RESULTS: Two studies of patients were discarded, one because of head motion and the other because of badly followed instructions. On the remaining patients the functional activations found in the visual cortex were consistent with the results of perimetric evaluation in all but one of the patients and all the normal subjects although the results of fMRI were highly dependent on the choices of the analysis thresholds. Visual functional MRI image guided data were used in five patients with occipital brain tumours. No added postoperative functional field defect was detected. CONCLUSIONS: There was a good correspondence between fMRI data and the results of perimetric evaluation although dependent on the analysis thresholds. Visual fMRI data registered into a frameless stereotactic device may be useful in surgical planning and tumour removal.

Adult↗
PubMed2001

[New MRI techniques in multiple sclerosis].

Early imaging investigations in multiple sclerosis (MS) described focal signs. Technological progress now suggests this concept should be revisited as more diffuse anomalies of the central nervous system are described, sometimes involving regions that appear normal with conventional imaging techniques. This integrative concept results largely from the contribution of magnetic resonance imaging techniques recently broadened to in vivo investigations. Technical developments in MRI now provide new contrast images (magnetization transfer, diffusion, anisotropic diffusion, functional MRI using the BOLD method) as well as new variants of conventional sequences designed to demonstrate specific aspects of the MS lesions: FLAIR sequence (a T2-weighted sequence), black holes (a particular aspect on T1-weighted images), cord atrophy (quantification of the axial section of the cord on T1-weighted sequences). Together these new methods should improve diagnostic sensitivity (FLAIR) or provide prognosis information not provided by conventional sequences (T2 or T2 weighted images with or without gadolinium injection).

Brain↗
PubMed2001

[Brain tumors: interest of magnetic resonance spectroscopy for the diagnosis and the prognosis].

Magnetic resonance spectroscopy (MRS) is a tool for a non-invasive monitoring of brain tumor metabolism. In vivo proton MRS became possible with the development of whole-body high-field magnets. First, it allows to distinguish brain tumors from abscesses. Second, along with other imaging techniques, it permits the differentiation of primary brain tumors, mainly gliomas, from tumors of various origins such as meningiomas or metastasis. However, its ability to give a grading of gliomas stays controversial. Choline, a marker of cell membrane proliferation, could give information on the degree of malignancy but reports on its role are somewhat contradictory. Brain tumor biopsy and histology stay mandatory in the management of brain tumors. In vitro MRS spectra obtained from tumor extracts show that the signal at 3.2ppm, the so-called "cholin peak", corresponds to several compounds among them, glycerophosphocholine, phosphocholine, and choline. Their repartition differs with the grade of the tumor. In vivo proton MRS is the only metabolic technique of non-invasive monitoring of treated brain tumors. It can separate recurrence from radionecrosis. Improved methodology and availability of MR imagers will strengthen its importance in the future.

Aspartic Acid↗
PubMed2001

[Diagnostic criteria of multiple sclerosis in neuroimaging].

Although sensitivity of MRI to MS is high, its specificity is limited and requires the use of criteria such as Paty's, Fazekas's and then Barkhof's, taking successively into account the technical progress and the use of contrast agents. In the later the confidence level brought by contrast enhancement is equivalent to that of 9 hyperintense lesions seen on T2-weighted imaging. Therefore MRI is now the first paraclinical test to perform for MS suspicion and is aimed at the diagnosis MS from the first clinical event, without need to wait for the second relapse for temporal dissemination confirmation. The goal is to be able to discuss early treatment if it becomes clear that it could prevent disease progression. The early evidence of spatial and temporal dissemination of the disease takes equally into account the clinical and MRI information and eliminates the previous terminology of "clinically defined MS". Presently the diagnosis is either confirmed or ruled out and in a limited number of cases or before the completion of the work up phase the category of "possible MS" is used. Although progress were also made in the field of prognosis evaluation of MS with MRI, it still brings less definitive information to predict individually the evolution of each form of the disease. This opens a large place for new techniques such as magnetisation transfer, spectroscopy and diffusion imaging which are already able to help pathophysiological understanding and which may play an increased role even at the individual level in the future.

Brain↗
PubMed2000

Cortical motor reorganization in akinetic patients with Parkinson's disease: a functional MRI study.

Using functional MRI (fMRI), we have studied the changes induced by the performance of a complex sequential motor task in the cortical areas of six akinetic patients with Parkinson's disease and six normal subjects. Compared with the normal subjects, the patients with Parkinson's disease exhibited a relatively decreased fMRI signal in the rostral part of the supplementary motor area (SMA) and in the right dorsolateral prefrontal cortex, as previously shown in PET studies. Concomitantly, the same patients exhibited a significant bilateral relative increase in fMRI signal in the primary sensorimotor cortex, lateral premotor cortex, inferior parietal cortex, caudal part of the SMA and anterior cingulate cortex. These fMRI data confirm that the frontal hypoactivation observed in patients with Parkinson's disease is restricted to the rostral part of the SMA and to the dorsolateral prefrontal cortex. These results also show that, apart from the lateral premotor and parietal cortices, increased fMRI signals can be found in other cortical motor areas of these patients, including the posterior SMA, the anterior cingulate cortex and the primary sensorimotor cortices, which are then likely to participate in the same putative attempt by the dopamine-denervated brain to recruit parallel motor circuits in order to overcome the functional deficit of the striatocortical motor loops.

Aged↗
PubMed2000

Functional MRI and intraoperative brain mapping to evaluate brain plasticity in patients with brain tumours and hemiparesis.

OBJECTIVE: To support the hypothesis about the potential compensatory role of ipsilateral corticofugal pathways when the contralateral pathways are impaired by brain tumours. METHODS: Retrospective analysis was carried out on the results of functional MRI (fMRI) of a selected group of five paretic patients with Rolandic brain tumours who exhibited an abnormally high ipsilateral/contralateral ratio of activation-that is, movements of the paretic hand activated predominately the ipsilateral cortex. Brain activation was achieved with a flexion extension of the fingers. Statistical parametric activation was obtained using a t test and a threshold of p<0.001. These patients, candidates for tumour resection, also underwent cortical intraoperative stimulation that was correlated to the fMRI spatial data using three dimensional reconstructions of the brain. Three patients also had postoperative control fMRI. RESULTS: The absence of fMRI activation of the primary sensorimotor cortex normally innervating the paretic hand for the threshold chosen, was correlated with completely negative cortical responses of the cortical hand area during the operation. The preoperative fMRI activation of these patients predominantly found in the ipsilateral frontal and primary sensorimotor cortices could be related to the residual ipsilateral hand function. Postoperatively, the fMRI activation returned to more classic patterns of activation, reflecting the consequences of therapy. CONCLUSION: In paretic patients with brain tumours, ipsilateral control could be implicated in the residual hand function, when the normal primary pathways are impaired. The possibility that functional tissue still remains in the peritumorous sensorimotor cortex even when the preoperative fMRI and the cortical intraoperative stimulations are negative, should be taken into account when planning the tumour resection and during the operation.

Aged↗
PubMed2000

[Practical role of functional MRI in neurosurgery].

INTRODUCTION: Since its description in the early 1990's, functional magnetic resonance imaging (fMRI) has been used first for research purposes, and after in clinical applications in the field of neurosurgery. The purpose of this article was to critically review the literature on fMRI to achieve a better understanding of the usefulness of fMRI in brain surgery for tumors, epilepsy surgery, and radiosurgery. MATERIAL AND METHODS: Medical literature databases containing peer-review articles dating from 1990 were queried for key words related to fMRI. RESULTS: On 3,065 references scanned for relevance, 256 articles with direct or indirect relationships between fMRI and neurosurgery were analyzed. DISCUSSION: fMRI can be useful in the selection of patients for whom a surgical resection is attempted and could aid in the decision-making whether to operate on a patient who has been previously considered inoperable. fMRI is a useful tool in the decisional scheme of treatment of low-grade astrocytomas or arteriovenous malformations in the rolandic area in intact or slightly impaired patients. fMRI can be repeated in selected patients with slow growing brain tumors or congenital lesions such as AVM to study cortical reorganization phenomena. In epilepsy surgery, the Wada-test could be substituted by fMRI to determine the hemispheric dominance of language. The choice of standardized tasks and a better understanding of analysis problems in the treatment of fMRI images must be achieved before drawing more accurate conclusions on fMRI and brain tumors.

Brain Diseases↗
PubMed2000

[Magnetic resonance imaging in multiple sclerosis].

The contribution of magnetic resonance imaging techniques to the clinical prognosis of multiple sclerosis. Magnetic resonance imaging (MRI) is a diagnostic technique with a high sensitivity for the detection of lesions, but with a poor pathological specificity. In the case of multiple sclerosis (MS), the improvement of diagnostic efficacy depends on a careful analysis of the clinical presentation and the use of increasingly stringent MRI criteria aimed at improving the specificity of the conventional MRI T2 sequences. New sequences such as fast spin-echo (also called turbo spin-echo) and FLAIR (fluid attenuated inversion recovery, a method derived from inversion recovery) have improved the visualization of lesions. MRI can under certain conditions be used to monitor the evolution of MS. Acute-phase monitoring is focused on observed changes in disease activity such as the appearance, recurrence or extension of lesions after i.v. injection of contrast medium, i.e., gadolinium (Gd)-enhanced MRI. In the chronic phase, the lesions is the aspect used as the monitoring criterion. However, MRI is still only a secondary criterion in phase III therapeutic trials due to its insufficient correlation with the disability. In neurological daily practice, conventional MRI is only of limited interest at the individual level in patient follow-up, as its prognostic value is poor. Moreover, the difficulty in determining the lesion load can only be excluded in the context of clinical trials, in which certain methodological precautions are taken. This is why techniques other than MRI are being investigated to obtain a better correlation with the clinical course of the disease, for instance the quantification of 'black holes' on T1 weighted images, and the measurement of cerebral and spinal atrophy. Adapted MRI techniques allow a weighted signal to be obtained via the movement (diffusion imaging), by the complexity of the molecular structure (magnetization transfer imaging), by chemical shift (spectroscopic imaging), or by local oxygenation (functional MRI). These new MRI techniques allow a more precise assessment of the pathological mechanisms involved in MS, such as edema, blood brain barrier break-down, demyelinisation, gliosis, cellular infiltration and axonal loss; they provide a better means of establishing the correlation between clinical impact and the destructive nature of the MS lesion. The importance of axonal loss has recently been confirmed in MS by analyzing MRI spectroscopic and neuropathological findings. In addition to magnetization transfer imaging, MR diffusion imaging and functional MRI are being intensively studied in order to assess their contribution to the study of reversibility of the degenerative process.

Brain↗
PubMed2000

Functional magnetic resonance imaging may avoid misdiagnosis of cochleovestibular nerve aplasia in congenital deafness.

OBJECTIVE: To investigate a narrow internal auditory canal (IAC) syndrome using functional magnetic resonance imaging (fMRI) of the auditory cortex. STUDY DESIGN: The study design was a case report. The follow-up period lasted 18 months. SETTING: The study was carried out in the audiology clinic of an ear, nose, and throat department and in the department of pediatric neuroradiology at a university hospital. MAIN OUTCOME MEASURES: Age-appropriate observational audiometry, objective audiovestibular tests, computed tomography (CT), magnetic resonance imaging (MRI), and (fMRI) of the auditory cortex were performed to analyze in detail the profound deafness of a young child. RESULTS: Audiovestibular examination demonstrated both measurable hearing and normal vestibulo-ocular reflex, and CT showed narrow IACs combined with normal labyrinths. Axial MR images completed by sagittal sections perpendicular to the IAC delineated a single nerve that was initially supposed to be the facial nerve. No cochleovestibular nerve was identified. However, fMRI performed with the patient under general anesthesia demonstrated activation of the primary auditory cortex during 1-kHz monaural stimulation on the left side. CONCLUSIONS: The absence of cochleovestibular nerve on MR studies cannot exclude connections between the inner ear and the central auditory pathways. This might be caused by a lack of spatial resolution of anatomical MR studies. The single nerve delineated within the IAC might also carry both facial and cochleovestibular fibers. Functional MRI can assess the cortical response to acoustic stimuli when aplasia of the cochleovestibular nerve is suspected. This case study illustrates a novel and atypical presentation of cochlear nerve dysplasia.

Acoustic Stimulation↗
PubMed1999

A multicenter measurement of magnetization transfer ratio in normal white matter.

To assess the importance of intercenter variations when measuring magnetization transfer ratio (MTR) in the brain, six European centers measured MTR in normal white matter. MTR ranged from 9 to 51 percent units (25 sequences). The effective flip angle of the saturating pulse divided by the pulse repetition time (ENRsat degrees/msec) was a good predictor of MTR (MTR = 3.25 ENRsat).

Brain↗