青壮年重症抑郁障碍的磁化传递成像研究

目的探讨青壮年重症抑郁障碍患者磁化传递率（MTR）值的改变及其与病程的相关性。方法根据美国精神障碍诊断与统计手册,选择临床晤谈诊断明确并且17项汉密尔顿抑郁量表评分≥18分的30例重症抑郁障碍患者,以及按照年龄、性别、利手性、受教育程度相匹配原则征集的30例正常对照者。采用3．0TMRI扫描仪采集磁化传递成像数据,统计参数图软件对所得MTR参数图进行标准化和平滑等预处理,再行基于体素的分析。MTR值的组间比较行双样本t检验,与病程的相关性分析采用Pearson相关分析。结果在统计参数图中,以团簇水平P〈0．05作为统计显著性阈值。与正常对照组相比,重症抑郁障碍组患者未发现MTR值差异有统计学意义的脑区;相关分析显示,其在左侧前额叶、顶叶、颞叶部分区域,以及双侧前扣带回等脑区与病程呈显著负相关。进一步亚组分析显示,长病程（〉60周）重症抑郁障碍患者MTR值在左侧额中回、双侧中扣带回、右侧小脑前叶低于与之相匹配的正常对照者;而短病程（≤60周）患者,MTR值则在左侧额中回、颞枕交界区、双侧前扣带回及邻近白质较正常对照者升高。结论不同病程重症抑郁障碍患者脑MTR值呈现不同改变模式,提示对重症抑郁障碍患者长期纵向随访的必要性,尤其是长期抗抑郁治疗对脑结构及功能的影响应作为重点研究课题。     

A volumetric MRI and magnetization transfer imaging follow-up study of patients with first-episode schizophrenia

Conventional MRI studies have not provided definitive evidence of progressive loss of brain volume in the early stages of schizophrenia, although more subtle changes may have gone undetected. We have looked for such subtle changes using volumetric MRI and magnetization transfer imaging (MTI), an advanced MRI technique sensitive to subtle neuropathological abnormalities. Magnetization transfer images and high-resolution volumetric T1-weighted images were acquired from 16 patients with first-episode schizophrenia at the start of the study and 3.7 years later. A group of 12 healthy controls were also scanned on two occasions. Images were processed using a voxel-based approach that allows whole-brain analysis. There was a group difference with a significant volume loss in the patients' white matter adjacent to the lateral ventricles in the right and left temporal lobes, in medial temporal gyrus, and in the white matter in and around the right middle frontal gyrus. No cortical differences were detected between the groups using MTI or volumetric MRI. The absence of any time-by-group interaction suggests that these abnormalities do not progress in the early stages of the disease. The results of the study need to be interpreted in the light of the small sample size and of the limitations of current image analysis methods.     

青壮年重症抑郁障碍的磁化传递成像研究

目的探讨青壮年重症抑郁障碍患者磁化传递率(MTR)值的改变及其与病程的相关性。方法根据美国精神障碍诊断与统计手册,选择临床晤谈诊断明确并且17项汉密尔顿抑郁量表评分≥18分的30例重症抑郁障碍患者,以及按照年龄、性别、利手性、受教育程度相匹配原则征集的30例正常对照者。采用3.0T MRI扫描仪采集磁化传递成像数据,统计参数图软件对所得MTR参数图进行标准化和平滑等预处理,再行基于体素的分析。MTR值的组间比较行双样本t检验,与病程的相关性分析采用Pearson相关分析。结果在统计参数图中,以团簇水平P<0.05作为统计显著性阈值。与正常对照组相比,重症抑郁障碍组患者未发现MTR值差异有统计学意义的脑区;相关分析显示,其在左侧前额叶、顶叶、颞叶部分区域,以及双侧前扣带回等脑区与病程呈显著负相关。进一步亚组分析显示,长病程(>60周)重症抑郁障碍患者MTR值在左侧额中回、双侧中扣带回、右侧小脑前叶低于与之相匹配的正常对照者;而短病程(≤60周)患者,MTR值则在左侧额中回、颞枕交界区、双侧前扣带回及邻近白质较正常对照者升高。结论不同病程重症抑郁障碍患者脑MTR值呈现不同改变模式,提示对重症抑郁障碍患者长期纵向随访的必要性,尤其是长期抗抑郁治疗对脑结构及功能的影响应作为重点研究课题。     

A magnetization transfer imaging study in patients with temporal lobe epilepsy and interictal psychosis.

BACKGROUND: Findings from previous neuropathological and neuroimaging studies in patients with epilepsy and interictal psychosis have been inconclusive, and both focal and widespread brain abnormalities have been reported. Thus, further investigation with advanced in vivo magnetic resonance imaging (MRI) techniques, such as magnetization transfer imaging, capable of detecting more subtle brain abnormalities, is warranted. METHODS: Twenty patients with temporal lobe epilepsy and interictal psychosis were compared with 20 nonpsychotic patients. Patients were matched with respect to conventional MRI findings. Each group comprised of 10 patients with hippocampal sclerosis (6 left, 4 right) and 10 patients without focal lesions on MRI. A voxel-based analysis was used for the group comparisons. RESULTS: Voxel-based analysis revealed significant reductions of magnetization transfer ratio (an index of signal loss derived from magnetization transfer imaging) in the left superior and middle temporal gyri in the psychotic patients for the subgroup of patients with no focal lesions on MRI. There were no significant volumetric differences between the psychotic and nonpsychotic patients. CONCLUSIONS: Focal cortical magnetization transfer ratio abnormalities in the left temporal lobe unrelated to volume changes can be demonstrated in some temporal lobe epilepsy patients with interictal psychosis. Our findings might reflect subtle neuropathological abnormalities that are undetected by conventional MRI.     

A diffusion tensor magnetic resonance imaging study of brain tissue from patients with migraine

OBJECTIVE: To measure in vivo, using diffusion tensor magnetic resonance imaging (DT-MRI) the extent of pathological damage of normal appearing brain tissue (NABT) from patients with migraine. METHODS: Dual echo and DT-MRI scans of the brain were acquired from 34 patients with migraine and 17 sex and age matched healthy volunteers. Mean diffusivity (MD) and fractional anisotropy (FA) histograms of the NABT were obtained from all subjects and the histograms' peak heights and average NABT MD and FA measured. When present, average MD and FA values of T2 visible lesions were also measured. RESULTS: In comparison with healthy volunteers, patients with migraine had lower MD histogram peak height (p=0.02) of the NABT. No differences were found in FA histogram derived metrics between migraine patients and healthy subjects. No difference was found for any MD and FA histogram derived metrics between migraine patients with and without brain MRI lesions, and between patients with and without aura. CONCLUSIONS: This study shows that, although brain damage may extend beyond T2 weighted abnormalities in patients with migraine, the severity of these "occult" changes is mild compared with that found in other diseases associated with white matter abnormality.     

A magnetization transfer histogram study of normal-appearing brain tissue in MS

OBJECTIVE: To evaluate 1) the ability of magnetization transfer ratio (MTR) histogram analysis to detect the extent of changes occurring outside MS lesions seen on conventional scans, 2) whether such changes vary in the different MS clinical phenotypes, 3) whether the changes are associated with the extent and severity of the macroscopic lesion load, and 4) the contribution to brain atrophy. METHODS: Dual-echo, T1-weighted, and MT scans of the brain were obtained from 77 patients with varying MS courses and 20 age- and sex-matched control subjects. To create MT histograms of the normal-appearing cerebral tissue, MS lesions were segmented from dual-echo scans, superimposed automatically, and nulled out from the coregistered and scalp-stripped MTR maps. Average MTR, peak height, and peak position were considered. T2 and T1 lesion loads, average lesion MTR, and brain volume were also measured. RESULTS: Average histogram MTR (p<0.0001) and peak position (p<0.0001) from patients with relapsing-remitting MS (RMMS) were lower than those from control subjects. Patients with primary progressive MS (PPMS) had lower average histogram MTR (p = 0.002) and histogram peak height (p = 0.01) than control subjects. Patients with secondary progressive MS (SPMS) had a lower peak height (p = 0.05) than those with RRMS. Average lesion MTR (p<0.0001) correlated highly with the histogram MTR. Average histogram MTR (p<0.0001) and T2 lesion load (p = 0.001) correlated highly with brain volume. CONCLUSIONS: The amount of microscopic changes account for an important fraction of the lesion load in MS. They may contribute to the development of brain atrophy and tend to be more evident in patients with secondary progressive MS.     

MRI and magnetization transfer imaging changes in the brain and cervical cord of patients with Devic's neuromyelitis optica

OBJECTIVES: To assess MRI and magnetization transfer (MT) imaging changes in the brain and cervical cord from patients with Devic's neuromyelitis optica (DNO), and to compare them with those from patients with MS. BACKGROUND: In MS, MT imaging detects changes within the normal-appearing brain tissue (NABT). MS lesions in the cord usually are isointense on T1-weighted images. No study has investigated these two aspects in patients with DNO. METHODS: The authors obtained dual echo, fast fluid-attenuated inversion recovery, T1-weighted, and MT scans of the brain from 8 DNO patients, 10 MS patients, and 9 healthy volunteers. T2-weighted, short-tau inversion recovery, T1-weighted, and MT scans of the cervical cord also were obtained. The authors identified lesions visible on the different scans and quantified the volumes for those in the brain. MT ratio (MTR) histogram analysis of the NABT and of the entire cervical cord also was performed. RESULTS: No brain abnormalities were found on the T2-weighted scans from healthy volunteers and from seven DNO patients. No significant difference was found for any of the NABT-MTR histogram metrics between DNO patients and controls, whereas MS patients had a significantly lower histogram average MTR and peak height. No abnormalities were seen on any of the scans of the cervical cord from healthy volunteers. All DNO patients had a single lesion longer than two vertebral segments. Five of them were hypointense on T1-weighted scans. The authors identified 24 cord lesions from MS patients: 22 were shorter than two vertebral segments and none was hypointense. There was no difference in cervical cord MTR histogram metrics between DNO and MS patients. CONCLUSIONS: This study demonstrates that patients with Devic's neuromyelitis optica (DNO) and MS have different imaging characteristics of the brain and cervical cord. This provides further evidence that DNO is a clinical entity separate from MS.     

Contribution of cervical cord MRI and brain magnetization transfer imaging to the assessment of individual patients with multiple sclerosis: a preliminary study

This study was performed to assess how established diagnostic criteria for brain magnetic resonance imaging (MRI) interpretation in cases of suspected multiple sclerosis (MS) (Barkhofs criteria) would perform in the distinction of MS from other diseases and whether other MR techniques (cervical cord imaging and brain magnetization transfer imaging [MTI]), might help in the diagnostic work-up of these patients. We retrospectively identified 64 MS and 59 non-MS patients. The latter group included patients with systemic immune-mediated disorders (SID; n=44) and migraine (n=15). All patients had undergone MRI scans of the brain (dual echo and MTI) and of the cervical cord (fast short-tau inversion recovery). The number and location of brain T2-hyperintense lesions and the number and size of cervical cord lesions were assessed. Brain images were also postprocessed to quantify the total lesion volumes (TLV) and to create histograms of magnetization transfer ratio (MTR) values from the whole of the brain tissue. Barkhofs criteria correctly classified 108/123 patients, thus showing an accuracy of 87.8%. "False negative" MS patients were 13, while 2 patients with systemic lupus erythematosus (SLE) were considered as "false positives". Using brain T2 TLV, nine of the "false negative" patients were correctly classified. Correct classification of 10 MS patients and both the SLE patients was possible based upon the presence or absence of one cervical cord lesion. Two MS patients with negative Barkhofs criteria and no cervical cord lesions were correctly classified based on their brain MTR values. Overall, only one MS patient could not be correctly classified by any of the assessed MR quantities. These preliminary data support a more extensive use of cervical cord MRI and brain MTI to differentiate between MS and other disorders in case of incondusive findings on T2-weighted MRI scans of the brain.     

In vivo evaluation of remyelination in rat brain by magnetization transfer imaging

The aim of this work was to assess quantitatively and qualitatively the ability of magnetization transfer imaging to follow in vivo remyelination. Demyelination lesions were induced in rats by the injection of L-alpha-lysophosphatidylcholine stearoyl into the corpus callosum and imaging was performed in vivo on a 4.7-Tesla system at different time points. The percentage of magnetization transfer ratio (MTR) decrease was calculated for each animal. To evaluate the MTR findings for remyelination, myelin was quantitated by histological analysis of the lesion size and counting the number of remyelinating axons. An MTR decrease was observed when demyelination was present at 7 days after injection. During the remyelinating phase between day 30 and 40 after injection, contralateral values almost complete returned to normal, thus indicating remyelination. Histologically, at days 30 and 40 after injection, the lesion area was reduced in size and the axons were surrounded by a thin myelin sheath, indicating the remyelination process. Statistical analysis showed that the profile of MTR values was significantly correlated with the course of remyelination. All the MTR changes show a correlation with both myelin damage and repair. In conclusion, the study of the MTR profile in this myelin lesion model demonstrates in vivo the loss of myelin and the presence of spontaneous remyelination. This methodological approach which can also be applied to multiple sclerosis patients to show demyelination, should prove helpful to determine the degree of spontaneous and therapeutically induced remyelination in multiple sclerosis lesions, and thus to validate therapeutic treatments for myelin repair.     

A conventional and magnetization transfer MRI study of the cervical cord in patients with MS

OBJECTIVE: To evaluate the contribution made by cervical cord damage, assessed using a fast short-tau inversion recovery (fast-STIR) sequence and magnetization transfer ratio (MTR) histogram analysis to the clinical manifestations of MS. BACKGROUND: Previous studies have failed to show significant correlations between the number and extent of T2 spinal cord lesions and the clinical status of patients with MS. Fast-STIR is more sensitive than T2-weighted imaging for detecting cervical cord MS lesions. MTR histogram analysis provides estimates of the overall disease burden in the cervical cord with higher pathologic specificity to the more destructive aspects of MS than T2-weighted scans. METHODS: We obtained fast-STIR and magnetization transfer (MT) scans from 96 patients with MS (52 with relapsing-remitting [RRMS], 33 with secondary progressive [SPMS], and 11 with primary progressive [PPMS] MS) and 21 control subjects. Dual-echo scans of the brain were also obtained and lesion load measured. Results: Eighty-one of the patients with MS had an abnormal cervical cord scan. Patients with SPMS had more cervical cord lesions and more images with visible cervical cord damage than did patients with RRMS or PPMS (p = 0.04). The entire cohort of patients with MS had lower average MTR of the cervical cord (p = 0.006) than control subjects. Compared to control subjects, patients with RRMS had similar cervical cord MTR histogram-derived measures, whereas those with PPMS had lower average MTR (p = 0.01) and peak height (p = 0.02). Patients with SPMS had lower histogram peak height than did those with RRMS (p = 0.03). The peak position and height of the cervical cord MTR histogram were independent predictors of the probability of having locomotor disability. We found no correlation between brain T2 lesion load and any of the cervical cord MTR histogram metrics. CONCLUSIONS: This study shows that the amount and severity of MS pathology in the cervical cord are greater in the progressive forms of the disease. An accurate assessment of cervical cord damage in MS gives information that can be used in part to explain the clinical manifestations of the disease.     

A longitudinal conventional and magnetization transfer magnetic resonance imaging study of optic neuritis

Eleven consecutive patients with a first episode of acute optic neuritis were evaluated, using conventional and magnetization transfer (MT) magnetic resonance imaging (MRI), in order to assess the temporal evolution of optic nerve (ON) damage and to investigate the correlation of ON damage with visual outcome and electrophysiological parameters. Patients underwent neuroophthalmological, neurological, electrophysiological, and MRI assessments at baseline and after three and 12 months. ON volumes were measured on coronal T1-weighted images using a local thresholding segmentation technique. MT ratio (MTR) from the ON was derived from gradient echo images. No significant volume difference was detected between affected and healthy ON, both at baseline and follow-up. At baseline, mean MTR values were significantly higher in affected ON than in healthy ON (P =0.001), whereas at months 3 and 12, the mean MTR values were significantly reduced in the affected ON (P =0.02 and 0.003, respectively). Mean MTR of the affected ON, corrected for healthy ON values, progressively decreased over time (P =0.04 at month 3 and P =0.0012 at month 12). On the contrary, MTR values of healthy ON remained stable. No correlations were found between MTR measures and clinical or electrophysiological data. This study shows the presence of subtle pathological changes, possibly due to residual demyelination and subsequent additional demyelination and impaired remyelination, in the ON of patients with a first episode of optic neuritis. In the early phase of optic neuritis, MT MRI is more sensitive than atrophy measurements in detecting disease-related changes.     

Brain MRI correlates of magnetization transfer imaging metrics in patients with multiple sclerosis.

Previous studies suggested that magnetization transfer ratio (MTR) histograms are highly correlated with other magnetic resonance imaging (MRI) measures and can be used as a reliable method for quantifying overall disease burden in multiple sclerosis (MS). However, the relative influence of burden and severity of macroscopic MS lesions and degree of brain atrophy on various MTR histogram parameters has not yet been fully elucidated. Aim of the present study was to investigate which MRI measure best predicts the values of MTR histogram parameters in MS patients. Forty-two MS patients underwent brain dual-echo. T1-weighted and magnetization transfer imaging (MTI) MRI scans. Hyperintense lesion load (LL) on proton density (PD)-weighted and hypointense LL on T1-weighted images were measured using a local thresholding technique. A measure of brain atrophy was derived from T1-weighted images by computing the volume of brain tissue segmented from a slab of five consecutive slices rostral to the velum interpositum. On MTI scans, MTR histogram analysis was performed for the whole brain and average lesion MTR was also calculated. PD-weighted LL, T1-weighted LL and brain volume were significantly correlated with several MTI-derived measures. When a multivariate analysis was performed, brain volume alone significantly predicted the values of all the MTR histogram-derived measures (P values ranged from 0.003 to 0.0002). The ratio between hypointense T1-weighted and hyperintense PD-weighted LL significantly predicted average lesion MTR (P<0.05). Our results confirm that MTR can be used as a reliable method to assess both the overall disease burden and the individual lesion intrinsic nature in MS patients. The significant influence of brain atrophy on MTR histogram parameters supports the concept that this method also provides information on the loss of brain parenchyma in MS.     

FLAIR and magnetization transfer imaging of patients with post-treatment Lyme disease syndrome.

OBJECTIVE: To determine patterns of abnormalities on cerebral MRI that may characterize subgroups of patients with post-treatment Lyme disease syndrome (PTLDS) and to help identify pathomechanisms of disease. METHODS: The authors analyzed the distribution of cerebral lesions in a cohort of 27 patients with PTLDS. A subgroup of eight patients with PTLDS was further studied using whole-brain magnetization transfer ratio measures to identify abnormalities not seen on T2-weighted images. RESULTS: Four patients had focal neurologic deficits, relapsing-remitting disease, and lesions in a distribution typical of MS. Twenty-three patients presented with nonfocal symptoms such as fatigue, subjective memory deficits, and mood disturbance. Twelve of these patients had normal MRI, including the more sensitive fluid-attenuated inversion recovery sequence, 10 had primarily punctate and subcortical lesions, and one patient had multiple periventricular lesions. CONCLUSIONS: In a portion of patients with post-treatment Lyme disease syndrome, white-matter hyperintensities tend to occur in subcortical arteriolar watershed areas and are not specific. Magnetization transfer ratio analysis did not provide evidence for structural abnormalities of the brain parenchyma in patients with nonfocal disease.     

The characterization of human brain tumor using magnetization transfer technique in magnetic resonance imaging

Abstract

The clinical applicabiity of magnetization transfer (MT) technique in magnetic resonance imaging (MRI) for the estimation of the histological and constitutional feature of brain tumors was investigated. MT effect was evaluated by measuring the MT ratio (MTR). The parameters in 1.5-tesla MRI system were as follows: TR, 50 msec; TE, 5 msec; flip angle, 30 degree; offset frequency of off-resonance MT pulse, 1000 Hz. The sequence was performed in 20 normal volunteers and 45 patients with brain tumors which were characterized histologically and surgically. The MTR for brain tumors was significantly lower than that for normal brain tissue (p < 0.05). The MTR for meningioma was higher than that for the other brain tumors (p < 0.05). In the meningiomas, MTR for fibrous type was higher than that for méningothélial type, but there was no statistical significance. Regarding the physical consistency for the brain tumors, as classified by surgery, there was a statistically significant difference in MTR between the soft tumor group (0.22 ± 0.03, n = 6) and the hard tumor group (0.36±0.04, n=10) (p < 0.01). This study suggested that the MT technique for patients with brain tumor may be useful to understand the characteristics of the tumors presurgically, based on the degree of intermolecular interaction of macromolecule such as protein. [Neurol Res 1999; 21: 250-254]     

Gray and white matter brain abnormalities in first-episode schizophrenia inferred from magnetization transfer imaging

BACKGROUND: Neuroimaging studies suggest that schizophrenia is associated with gray and possibly white matter changes. It is unclear whether these changes are present at illness onset or which brain structures are selectively affected. New imaging methods such as magnetization transfer imaging may be more sensitive than conventional volumetric imaging to the subtle structural brain changes in schizophrenia. METHODS: High-resolution volumetric T1-weighted images and magnetization transfer images were acquired from 30 patients (29 with first-episode schizophrenia and 1 with schizophreniform psychoses) and 30 control subjects. Images were processed using voxel-based morphometry, which allows whole-brain analysis. RESULTS: Compared with controls, the magnetization transfer ratio (an index of signal loss derived from magnetization transfer imaging) was reduced bilaterally in the medial prefrontal cortex (right greater than left), insula (left greater than right), and white matter incorporating the fasciculus uncinatus (left greater than right) in the patient group. Analysis of the T1-weighted images did not reveal significant volumetric differences between patients and controls. CONCLUSIONS: Gray and white matter abnormalities are present in schizophrenia at illness onset. The magnetization transfer ratio is sensitive to these abnormalities, which cannot be explained by detectable atrophy in our patient group.     

Perilesional gliosis and seizure outcome: a study based on magnetization transfer magnetic resonance imaging in patients with neurocysticercosis

We studied the effect of perilesional gliosis on seizure recurrence after stopping antiepileptic drug (AED) therapy in 108 patients with a solitary cysticercal brain cyst. All patients received albendazole therapy in the beginning, and magnetic resonance imaging (MRI) done after 2 seizure-free years showed complete disappearance of the lesion in 67, partial degeneration in 12, and healing by calcification in 29. The gliosis, which was not visible on initial MRI, was observed near the lesion in 22 (20%) patients on T1-weighted magnetization transfer spin-echo (MTSE) MRI. Initial seizure control was difficult with single AED therapy in 16 of 22 patients with gliosis but only in 8 of 86 patients without gliosis. On stopping AED therapy, patients with perilesional gliosis had a higher incidence of seizure recurrence (19 of 22 patients) compared with those who did not demonstrate gliosis (9 of 86 patients). The presumption that gliosis visible on MTSE MRI correlates with seizure recurrence had a high specificity (96%) but only moderate sensitivity (68%). Our findings suggest that there is a group of patients with neurocysticercosis in whom the risk of seizure recurrence is actually high. Several such patients have perilesional gliosis that can be identified on T1-weighted MTSE MRI. These patients probably need long-term AED administration.     

The characterization of human brain tumor using magnetization transfer technique in magnetic resonance imaging.

The clinical applicability of magnetization transfer (MT) technique in magnetic resonance imaging (MRI) for the estimation of the histological and constitutional feature of brain tumors was investigated. MT effect was evaluated by measuring the MT ratio (MTR). The parameters in 1.5-tesla MRI system were as follows: TR, 50 msec; TE, 5 msec; flip angle, 30 degree; offset frequency of off-resonance MT pulse, 1000 Hz. The sequence was performed in 20 normal volunteers and 45 patients with brain tumors which were characterized histologically and surgically. The MTR for brain tumors was significantly lower than that for normal brain tissue (p < 0.05). The MTR for meningioma was higher than that for the other brain tumors (p < 0.05). In the meningiomas, MTR for fibrous type was higher than that for meningothelial type, but there was no statistical significance. Regarding the physical consistency for the brain tumors, as classified by surgery, there was a statistically significant difference in MTR between the soft tumor group (0.22 +/- 0.03, n = 6) and the hard tumor group (0.36 +/- 0.04, n = 10) (p < 0.01). This study suggested that the MT technique for patients with brain tumor may be useful to understand the characteristics of the tumors presurgically, based on the degree of intermolecular interaction of macromolecule such as protein.     

A preliminary diffusion tensor and magnetization transfer magnetic resonance imaging study of early-onset multiple sclerosis

BACKGROUND: Early-onset multiple sclerosis (MS) typically has a more favorable course than adult-onset disease. OBJECTIVE: To assess the extent of microscopic tissue damage in the brain and cervical cord of patients with early-onset MS. DESIGN: During a single magnetic resonance imaging session, images of the brain and spinal cord were obtained using diffusion tensor and magnetization transfer magnetic resonance imaging. PATIENTS: We studied 13 patients with early-onset MS and 10 healthy volunteers. RESULTS: Compared with control subjects, patients with early-onset MS showed only a slight increase of the average mean diffusivity of the normal-appearing brain tissue. CONCLUSION: The relatively modest central nervous system damage detected in these patients might explain why early-onset MS typically has a more favorable clinical course than adult-onset MS.     

A brain magnetization transfer MRI study with a clinical follow up of about four years in patients with clinically isolated syndromes suggestive of multiple sclerosis

Whereas it is important to gain prognostic information in patients with clinically isolated syndromes (CIS) suggestive of multiple sclerosis (MS), there is still a lack of definitive data about the significance of normal-appearing white (NAWM) and gray (NAGM) matter damage in these patients. The aim of this study was to clarify the role of magnetization transfer magnetic resonance imaging (MT MRI) in assessing “occult” damage at the earliest clinical stage of MS. Dual echo, post-contrast T1-weighted, and MT MRI were obtained from 43 CIS patients with paraclinical evidence of spatial disease dissemination within 3 months from disease onset and from 22 controls. In patients, conventional MRI was obtained after 3 and 12 months from the baseline assessment, to detect disease dissemination in time (DIT). A neurological examination was also conducted to ascertain the occurrence of relapses for an average follow up period of 1389 (range = 420–1847) days. MTR maps were derived and NAWM and NAGM MT ratio (MTR) histograms were analyzed. During the follow up, 30 patients showed MRI evidence of DIT, and 21 experienced a relapse. T2 lesion volume (LV) was significantly higher in patients with DIT than in those without (p = 0.005). MTR histogram variables did not significantly differ between patients with MRI or clinical DIT. T2 LV was the only significant predictor of clinical DIT at follow-up (p = 0.001). This study shows that MT MRI-detectable damage to NAWM and NAGM may not be an important feature of all patients at presentation with a CIS highly suggestive of MS and that such a damage may develop with subsequent disease evolution. Received in revised form: 14 April 2006