Proton MR spectroscopy features of normal appearing white matter in neurofibromatosis type 1 (original) (raw)
Related papers
1995
To use proton MR spectroscopy in patients with neurofibromatosis type 1 to determine: (a) the spectroscopic characteristics of hamartomas and compare them with that of gliomas; (b) whether differences exist between patients with and without learning disabilities; and (c) spectroscopic patterns in normal-appearing brain (by MR imaging) in patients with and without focal lesions. METHODS: Seventeen proton MR spectroscopy volumes were obtained in 10 patients with neurofibromatosis type 1 (including hamartomas, N ϭ 7; normal-appearing brain, N ϭ 10). Seven patients had learning disorders, and 3 were mentally normal. Ten healthy volunteers and 10 patients with pathologically proved gliomas (all grades) were also examined. N-Acetyl aspartate/ creatine, creatine/choline, and N-acetyl aspartate/choline ratios were calculated for all samples. RESULTS: (a) Hamartomas showed higher N-acetyl aspartate/creatine, creatine/choline, and N-acetyl aspartate/choline ratios than gliomas. Hamartomas showed N-acetyl aspartate/creatine, creatine/choline, and N-acetyl aspartate/choline ratios similar to those of healthy volunteers. (b) No significant differences in N-acetyl aspartate/creatine, creatine/choline, and N-acetyl aspartate/ choline ratios were found in patients who had neurofibromatosis type 1 with and without learning disabilities. (c) N-acetyl aspartate/creatine, creatine/choline, and N-acetyl aspartate/choline ratios were similar for patients who had neurofibromatosis type 1 with and without focal hamartomas and in healthy volunteers. CONCLUSIONS: (a) Hamartomas have a proton MR spectroscopy pattern different from that of glioma and similar to that of normal brain. (b) As performed in this study, proton MR spectroscopy did not show significant differences in patients who had neurofibromatosis type 1 with and without learning disabilities. (c) Patients who have neurofibromatosis type 1 with and without hamartomas seem to have normal intervening brain by proton MR spectroscopy when compared with healthy volunteers.
Neurofibromatosis type 1: the evolution of deep gray and white matter MR abnormalities
AJNR. American journal of neuroradiology, 1994
To investigate the evolution of deeply located high-signal-intensity abnormalities of the brain on T2-weighted MR images of patients with neurofibromatosis type 1 (NF-1). The study consists of two patient groups: 1) retrospective evaluation of MR scans of 24 symptomatic NF-1 patients, 10 of whom were sequentially studied, and 2) prospective MR evaluations of 20 asymptomatic NF-1 subjects from 14 families; 2 of these families were sequentially studied. Deeply located, high-signal-intensity abnormalities on T2-weighted images were noted in 34 of 44 NF-1 subjects (77%). If NF-1 patients are grouped according to age, 28 of 30 subjects (93%) younger than 15 years had the lesions, whereas 4 of 7 subjects (57%) between 16 and 30 years, and 2 of 7 subjects (29%) older than 31 years had lesions. High-signal lesions in basal ganglia and brain stem were demonstrated in all decades with relatively high frequency. Lesions in the cerebellar white matter and dentate nuclei were mainly found in the...
Synthetic MRI in Neurofibromatosis Type 1
American Journal of Neuroradiology, 2021
BACKGROUND AND PURPOSE: Synthetic MRI enables the generation of various contrast-weighted images and quantitative data in a reasonable scanning time. We aimed to use synthetic MRI to assess the detection and underlying tissue characteristics of focal areas of signal intensity and normal-appearing brain parenchyma and morphometric alterations in the brains of patients with neurofibromatosis type 1. MATERIALS AND METHODS: Conventional MR imaging and synthetic MRI were prospectively obtained from 19 patients with neurofibromatosis type 1 and 18 healthy controls. Two neuroradiologists independently evaluated focal areas of signal intensity on both conventional MR imaging and synthetic MRI. Additionally, automatically segmented volume calculations of the brain in both groups and quantitative analysis of myelin, including the focal areas of signal intensity and normal-appearing brain parenchyma, of patients with neurofibromatosis type 1 were performed using synthetic MRI. RESULTS: The comparison of conventional MR imaging and synthetic MRI showed good correlation in the supratentorial region of the brain (k ¼ 0.82-1). Automatically segmented brain parenchymal volume, intracranial volume, and GM volumes were significantly increased in the patients with neurofibromatosis type 1 (P , .05). The myelin-correlated compound, myelin fraction volume, WM fraction volume, transverse relaxation rate, and longitudinal relaxation rate values were significantly decreased in focal areas of signal intensity on myelin and WM maps (P , .001); however, GM, GM fraction volume, and proton density values were significantly increased on the GM map (P , .001). CONCLUSIONS: Synthetic MRI is a potential tool for the assessment of morphometric and tissue alterations as well as the detection of focal areas of signal intensity in patients with neurofibromatosis type 1 in a reasonable scan time. ABBREVIATIONS: BPF ¼ brain parenchymal fraction; BPV ¼ brain parenchymal volume; cMRI ¼ conventional MRI; FASI ¼ focal areas of signal intensity; GMFvol ¼ mean amount of GM within a single voxel; HC ¼ healthy control; ICV ¼ intracranial volume; MY ¼ myelin; MyCvol ¼ myelin correlated fraction volume; MyF ¼ myelin fraction; MyV ¼ myelin correlated volume; NABP ¼ normal-appearing brain parenchyma; NF-1 ¼ neurofibromatosis type 1; NoN, non-GM/ WM/CSF; PD ¼ proton density; QRAPMASTER ¼ quantification of relaxation times and proton density by multiecho acquisition of a saturation-recovery using turbo spin-echo readout; R1 ¼ longitudinal relaxation rate; R2 ¼ transverse relaxation rate; SyMRI ¼ synthetic MRI; WMFvol ¼ the mean amount of WM within a single voxel
Annals of Neurology, 2000
Neurofibromatosis type 1 is a common autosomal dominant disorder associated with learning disabilities. In addition to gliomas and other tumors, T2 hyperintense lesions (unidentified bright objects or UBOs) are frequently found in the globus pallidus, cerebellum, and white matter regions. To better characterize supratentorial UBO functional significance, we studied by quantitative magnetic resonance spectroscopic imaging (MRSI) 9 male subjects with neurofibromatosis type 1 (age, 6 -19 years) and 9 age-matched and sex-matched controls. Maps of the anatomical distribution of the metabolites choline (Cho), N-acetylaspartate (NAA), and creatine were calculated in four axial 15-mm slices. Absolute metabolite concentrations within UBOs, unaffected globus pallidus, and thalami demonstrated an age-related pattern, characterized by elevated Cho and relatively preserved NAA in younger subjects (<10 years) and reduced NAA and normal Cho in older subjects. These changes were found in both UBOs and thalami but were only significant for NAA, NAA/creatine, and NAA/Cho in the latter region. Decreases in NAA ratios were most severe in the thalami of subjects with UBOs in the globus pallidus, whereas UBOs showed similar but milder abnormalities than those in the thalamus. We speculate that the MRSI metabolic abnormality may represent a more generalized phenomenon, without a T2 signal counterpart in the affected brain regions. Based on the neuropathological study by DiPaolo and colleagues (1995), we postulate that Cho elevations reflect increased myelin turnover in areas of intramyelinic edema, which is followed by neuropil injury (reduced NAA). Temporal progression and behavioral correlates of these MRSI changes deserve further exploration.
Neurofibromatosis type 1: Diffusion weighted imaging findings of brain
European Journal of Radiology, 2005
Purpose: The purposes of this study were to evaluate the differences in apparent diffusion coefficient (ADC) values between infra and supratentorial unidentified bright objects (UBOs), between UBOs and normal appearing side (NAS, contralateral regions of the UBOs and/or normal appearing region without UBOs) in the neurofibromatosis type 1 patients (NF1) and control group and also to investigate correlation between age and ADC values. Methods: A total of 30 patients and 26 healthy controls were included. The MRI examination consisted of routine imaging and diffusion weighted imaging (DWI). Seven distinct locations (frontal, parieto-occipital and cerebellar white matter, globus pallidum, thalamus, hippocampus, and midbrain) were selected for the analysis. The ADC values were calculated directly from these automatically generated ADC maps with ROI.
Journal of Neurology, Neurosurgery & Psychiatry, 1993
Thirty eight patients with neurofibromatosis 1 (NFI) had neurological examinations, intellectual assessments and MRI scans. Increased intensity lesions on T2 weighted images were found in 13 patients. These abnormalities were more common in patients aged under 18 years. The lesions occurred predominantly in the basal ganglia, brainstem and cerebellum, and were multiple in 11 patients. They did not produce symptoms or neurological deficit in any patient and did not enhance with gadolinium-meglumine-triamine-pentacetic acid contrast medium (Gd-DTPA). In 2 patients, however, the abnormalities exerted mass effect distorting the brain and in 3 patients they occurred in conjunction with known gliomas. The lesions remained unchanged over a three year follow up period. The nature of the lesions is uncertain but the fact that they may produce mass effect and occur in association with gliomas suggests that they have malignant potential. There was no correlation between the presence of these abnormalities and intellectual impairment.
Age-related findings on MRI in neurofibromatosis type 1
Pediatric Radiology, 2006
Background: T2 hyperintensities (T2H) on MRI are the most common CNS lesions in individuals with neurofibromatosis type 1 (NF1). Objectives: The aim was to determine the frequency, signal characteristics and localization of T2H at different ages. In addition, we examined the sensitivity of different MR imaging sequences in detecting these lesions. Materials and methods: We studied prospectively a cohort of children, adolescents and young adults with NF1 using T2-volume (T2-V) and conventional MRI sequences. Lesions were designated as either discrete or diffuse, and the region of signal abnormality was recorded. A total of 103 patients were studied (age range 8.0-25.4 years, mean 13.9 years). Results: The frequency, size, and intensity of T2H decreased with age in the basal ganglia (BG) and the cerebellum/brainstem (CB/BS). The majority of thalamic and CB/BS lesions were diffuse. Of the total cohort, 80% had diffuse bilateral hippocampal hyperintensities and 18.4% had hemispheric lesions best demonstrated on FLAIR; there was no significant difference in the frequency or signal intensity of hemispheric lesions with age. Conclusion: Lesions in the cerebral hemispheres and hippocampus imaged by MR do not change in prevalence over time, suggesting a different pathological basis from the lesions in the in BG and CB/BS that resolve with age.