Prospective, Longitudinal Study of Clinical Outcome and Morphometric Posterior Fossa Changes after Craniocervical Decompression for Symptomatic Chiari I Malformation.

BACKGROUND AND PURPOSE: The time course of changes in posterior fossa morphology, quality of life, and neurologic function of patients with Chiari I malformation after craniocervical decompression requires further elaboration. To better understand the pace of these changes, we longitudinally studied patients with Chiari I malformation, with or without syringomyelia, before and after the operation for up to 5 years. MATERIALS AND METHODS: Thirty-eight symptomatic adult patients (35 women, 3 men) diagnosed with Chiari I malformation only (n = 15) or Chiari I malformation and syringomyelia (n = 23) and without previous Chiari I malformation surgery were enrolled in a clinical study. Patients underwent outpatient study visits and MR imaging at 7 time points (ie, initial [before the operation], 3 months, 1 year, 2 years, 3 years, 4 years, and 5 years) during 5 years. The surgical procedure for all patients was suboccipital craniectomy, C1 laminectomy, and autologous duraplasty. RESULTS: Morphometric measurements demonstrated an enlargement of the CSF areas posterior to the cerebellar tonsils after the operation, which remained largely stable through the following years. There was a decrease in pain and improved quality of life after the operation, which remained steady during the following years. Reduction in pain and improved quality of life correlated with CSF area morphometrics. CONCLUSIONS: Most changes in MR imaging morphometrics and quality of life measures occurred within the first year after the operation. A 1-year follow-up period after Chiari I malformation surgery is usually sufficient for evaluating surgical efficacy and postoperative MR imaging changes.

Chronic multiple sclerosis lesions: characterization with high-field-strength MR imaging.

PURPOSE: To elucidate the mechanism of magnetic resonance (MR) imaging contrast in multiple sclerosis (MS) lesion appearance by using susceptibility-weighted imaging and to assess with histologic correlation the role of iron and myelin in generating this MR imaging contrast. MATERIALS AND METHODS: Each patient provided written consent to a human subject protocol approved by an institutional review board. High-spatial-resolution susceptibility-weighted 7.0-T MR images were obtained in 21 patients with MS. Contrast patterns in quantitative phase and R2* images, derived from 7.0-T data, were investigated in 220 areas defined as chronic MS lesions on conventional T2-weighted fluid-attenuated inversion recovery, T2-weighted, and T1-weighted spin-echo images. The presence of positive or negative phase shifts (ie, decreased or increased MR frequency, respectively) was assessed in each lesion. In addition, postmortem MR imaging was performed at 7.0 T and 11.7 T, and its results were correlated with those of immunohistochemical staining specific for myelin, iron, and ferritin. RESULTS: The majority (133 [60.5%] of 220) of the identified lesions had a normal phase and reduced R2*. A substantial fraction of the lesions (84 [38.2%] of 220) had negative phase shift, either uniformly or at their rim, and a variety of appearances on R2* maps. These two lesion contrast patterns were reproduced in the postmortem MR imaging study. Comparison with histologic findings showed that, while R2* reduction corresponded to severe loss of both iron and myelin, negative phase shift corresponded to focal iron deposits with myelin loss. CONCLUSION: Combined analysis of 7.0-T R2* and phase data may help in characterizing the pathologic features of MS lesions. The observed R2* decreases suggest profound myelin loss, whereas negative phase shifts suggest a focal iron accumulation.

Tracking iron in multiple sclerosis: a combined imaging and histopathological study at 7 Tesla.

Previous authors have shown that the transverse relaxivity R(2)* and frequency shifts that characterize gradient echo signal decay in magnetic resonance imaging are closely associated with the distribution of iron and myelin in the brain's white matter. In multiple sclerosis, iron accumulation in brain tissue may reflect a multiplicity of pathological processes. Hence, iron may have the unique potential to serve as an in vivo magnetic resonance imaging tracer of disease pathology. To investigate the ability of iron in tracking multiple sclerosis-induced pathology by magnetic resonance imaging, we performed qualitative histopathological analysis of white matter lesions and normal-appearing white matter regions with variable appearance on gradient echo magnetic resonance imaging at 7 Tesla. The samples used for this study derive from two patients with multiple sclerosis and one non-multiple sclerosis donor. Magnetic resonance images were acquired using a whole body 7 Tesla magnetic resonance imaging scanner equipped with a 24-channel receive-only array designed for tissue imaging. A 3D multi-gradient echo sequence was obtained and quantitative R(2)* and phase maps were reconstructed. Immunohistochemical stainings for myelin and oligodendrocytes, microglia and macrophages, ferritin and ferritin light polypeptide were performed on 3- to 5-µm thick paraffin sections. Iron was detected with Perl's staining and 3,3'-diaminobenzidine-tetrahydrochloride enhanced Turnbull blue staining. In multiple sclerosis tissue, iron presence invariably matched with an increase in R(2)*. Conversely, R(2)* increase was not always associated with the presence of iron on histochemical staining. We interpret this finding as the effect of embedding, sectioning and staining procedures. These processes likely affected the histopathological analysis results but not the magnetic resonance imaging that was obtained before tissue manipulations. Several cellular sources of iron were identified. These sources included oligodendrocytes in normal-appearing white matter and activated macrophages/microglia at the edges of white matter lesions. Additionally, in white matter lesions, iron precipitation in aggregates typical of microbleeds was shown by the Perl's staining. Our combined imaging and pathological study shows that multi-gradient echo magnetic resonance imaging is a sensitive technique for the identification of iron in the brain tissue of patients with multiple sclerosis. However, magnetic resonance imaging-identified iron does not necessarily reflect pathology and may also be seen in apparently normal tissue. Iron identification by multi-gradient echo magnetic resonance imaging in diseased tissues can shed light on the pathological processes when coupled with topographical information and patient disease history.

Lesions by tissue specific imaging characterize multiple sclerosis patients with more advanced disease.

BACKGROUND: Cerebrospinal fluid tissue specific imaging (CSF-TSI), a newly implemented magnetic resonance imaging (MRI) technique, allows visualization of a subset of chronic black holes (cBHs) with MRI characteristics suggestive of the presence of CSF-like fluid, and representing lesions with extensive tissue destruction. OBJECTIVE: To investigate the relationship between lesions in CSF-TSI and disease measures in patients with multiple sclerosis (MS). METHODS: Twenty-six patients with MS were imaged at 3.0 T, obtaining T(1)-weighted (T(1)-w) and T(2)-w spin echo (SE), T(1) volumetric images and CSF-TSI images. We measured: (i) lesion volume (LV) in T(1)-w (cBH-LV) and T(2)-w SE images, and in CSF-TSI; (ii) brain parenchyma fraction (BPF). Differences between patients with and without CSF-TSI lesions were analyzed and association between clinical and MRI metrics were investigated. RESULTS: cBHs were seen in 92% of the patients while lesions in CSF-TSI were seen in 40%. Patients with CSF-TSI lesions were older, with longer disease duration, higher disability scores, larger cBH-LV and T(2)-LV, and lower BPF than patients without CSF-TSI lesions (≤0.047). Partial correlation analysis correcting for T(2)-LV, cBH-LV and BPF showed an association (p < 0.0001, r = 0.753) between CSF-TSI LV and disability score. CONCLUSIONS: CSF-TSI lesions characterize patients with more advanced disease and probably contribute to the progress of disability.

T1 cortical hypointensities and their association with cognitive disability in multiple sclerosis.

BACKGROUND: Neocortical lesions (NLs) largely contribute to the pathology of multiple sclerosis (MS), although their relevance in patients' disability remains unknown. OBJECTIVE: To assess the incidence of T(1) hypointense NLs by 3.0-Tesla magnetic resonance imaging (MRI) in patients with MS and examine neocortical lesion association with cognitive impairment. METHODS: In this case-control study, 21 MS patients and 21 age-, sex- and years of education-matched healthy volunteers underwent: (i) a neuropsychological examination rating cognitive impairment (Minimal Assessment of Cognitive Function in MS); (ii) a 3.0-Tesla MRI inclusive of an isotropic 1.0 mm(3) three-dimensional inversion prepared spoiled gradient-recalled-echo (3D-IRSPGR) image and T(1)- and T(2)-weighted images. Hypointensities on 3D-IRSPGR lying in the cortex, either entirely or partially were counted and association between NLs and cognitive impairment investigated. RESULTS: A total of 95 NLs were observed in 14 (66.7%) patients. NL+ patients performed poorer (p = 0.020) than NL-patients only on the delayed recall component of the California Verbal Learning Test. This difference lost statistical significance when a correction for white matter lesion volume was employed. CONCLUSIONS: Although T( 1) hypointense NLs may be present in a relatively high proportion of multiple sclerosis patients, the impact that they have in cognitive impairment is not independent from white matter disease.

Eccrine spiradenoma mimicking a painful traumatic neuroma: case report.

Diagnosing and treating patients with persistent neuropathic pain associated with peripheral nerve lesions can be challenging. The authors report the rare case of a painful eccrine spiradenoma treated as a traumatic neuroma for many years because of a history of acute trauma, the presence of a tender palpable mass, and symptoms of allodynia. Surgical excision of the neoplasm completely relieved the pain and hypersensitivity that 2 prior surgeries and other nonsurgical treatments failed to resolve. The diagnosis of eccrine spiradenoma was not established until resection and histopathological analysis of the tissue. This case highlights the need to develop and consider an extensive list of differential diagnoses, including eccrine spiradenoma, for peripheral nerve lesions that fail to respond to treatment.

Heterogeneity of Multiple Sclerosis White Matter Lesions Detected With T2*-Weighted Imaging at 7.0 Tesla.

BACKGROUND AND PURPOSE: Postmortem studies in multiple sclerosis (MS) indicate that in some white matter lesions (WM-Ls), iron is detectable with T2*-weighted (T2*-w), and its reciprocal R2* relaxation rate, magnetic resonance imaging (MRI) at 7.0 Tesla (7T). This iron appears as a hyperintense rim in R2* images surrounding a hypointense core. We describe how this observation relates to clinical/radiological characteristics of patients, in vivo. METHODS: We imaged 16 MS patients using 3T and 7T scanners. WM-Ls were identified on T1-w / T2-w 3T-MRIs. Thereafter, WM-Ls with a rim of elevated R2* at 7T were counted and compared to their appearance on conventional MRIs. RESULTS: We counted 36 WM-Ls presenting a rim of elevated R2* in 10 patients. Twenty-three (64%) lesions coincided with focal WM-Ls on T2-w MRIs; 13 (36%) coincided with only portions of larger lesions on T2-w images; and 20 (56%) corresponded to a hypointense chronic black hole. WM-Ls presenting a rim of elevated R2* were seen in both relapsing-remitting patients with low disability and in those with long-standing secondary progressive MS. CONCLUSIONS: WM-Ls with a contour of high R2* are present at different MS stages, potentially representing differences in the contribution of iron in MS disease evolution.

Cognitive impairment and its relation to imaging measures in multiple sclerosis: a study using a computerized battery.

BACKGROUND AND PURPOSE: Cognitive impairment (CI) is an important component of multiple sclerosis (MS) disability. A complex biological interplay between white matter (WM) and gray matter (GM) disease likely sustains CI. This study aims to address this issue by exploring the association between the extent of normal WM and GM disease and CI. METHODS: Cognitive function of 24 MS patients and 24 healthy volunteers (HVs) was studied using the Automated Neuropsychological Assessment Metrics (ANAM) battery. WM focal lesions and normal appearing WM (NAWM) volume in patients, cortical thickness (CTh) and deep GM structure volumes in both patients and HVs were measured by high field strength (3.0-Tesla; 3T) imaging. RESULTS: An analysis of covariance showed that patients performed worse than HVs on Code Substitution Delayed Memory (P = .04) and Procedural Reaction Time (P = .05) indicative of reduced performance in memory, cognitive flexibility, and processing speed. A summary score (Index of Cognitive Efficiency) indicating global test battery performance was also lower for the patient group (P = .04). Significant associations, as determined by the Spearman rank correlation tests, were noted between each of these 3 cognitive scores and measures of NAWM volume [CDD-TP1(r = .609; P = .0035), PRO-TP1 (r = .456; P = .029) and ICE (r = .489; P = .0129)], CTh (r = .5; P ≤ .05) and volume of subcortical normal appearing GM (NAGM) structures (r = .4; P≤ .04), but not WM lesions. CONCLUSIONS: Both NAWM and NAGM volumes are related to CI in MS. The results highlight once again the urgent need to develop pharmacological strategies protecting patients from widespread neurodegeneration as possible preventive strategies of CI development.

Quality and quantity of diffuse and focal white matter disease and cognitive disability of patients with multiple sclerosis.

BACKGROUND AND PURPOSE: Using high-field magnetic resonance imaging (MRI), we investigated the relationships between white matter (WM) lesion volume (LV), normal-appearing WM (NAWM) normalized volume, WM-lesion and NAWM magnetization transfer ratios (MTRs), brain parenchyma fraction (BPF), and cognitive impairment (CI) in multiple sclerosis (MS). METHODS: Twenty-four patients and 24 healthy volunteers (age, sex, and years of education-matched) underwent a 3.0 Tesla (3T) scan and evaluation of depression, fatigue, and CI using the Minimal Assessment of Cognitive Function in MS (MACFIMS) battery. RESULTS: In this clinically relatively well-preserved cohort of patients (median score on the Expanded Disability Status Scale=1.5), CI was detected on Symbol Digit Modalities Test (SDMT), California Verbal Learning Test-II (CVLT-II), and Controlled Oral Word Association Test. MT data were available in 19 pairs on whom correlation analyses were performed. Associations were seen between SDMT and normalized NAWM volume (P=.034, r=.502), CVLT-II long delay and normalized NAWM volume (P=.012, r=.563), WM-LV (P=.024, r=.514), and BPF (P=.002, r=.666). CONCLUSIONS: The use of 3T MRI in a sample of clinically stable MS patients shows the importance of WM disease in hampering processing speed and word retrieval.

Heterogeneity in response to interferon beta in patients with multiple sclerosis: a 3-year monthly imaging study.

OBJECTIVES: To investigate the heterogeneity in magnetic resonance image (MRI) patterns of response to interferon beta across patients with multiple sclerosis or within an individual patient over time. DESIGN, SETTING, AND PATIENTS: Fifteen patients with relapsing-remitting multiple sclerosis underwent monthly MRIs and clinical examinations (6-month pretherapy phase and 36-month therapy phase) and bimonthly neutralizing antibody tests. On each MRI, the total number of contrast-enhancing lesions was noted. Therapy MRI responders were defined as those with a reduction of 60% or more in the total number of contrast-enhancing lesions during each semester of therapy. INTERVENTION: Subcutaneous administration of interferon beta-1b, 250 microg, every other day for 3 years. MAIN OUTCOME MEASURE: Reduction in the number of contrast-enhancing lesions. RESULTS: Eight patients (53.3%) were MRI responders and 7 (46.7%) were nonresponders. Of those 7, 3 (20.0%) had only an initial optimal reduction of the total number of contrast-enhancing lesions, 2 (13.3%) never reached an optimal response, and 2 (13.3%) had a delayed optimal response. No clear association between neutralizing antibody profile and MRI response was evident. CONCLUSIONS: Multiple MRI evaluations disclose that approximately only half of the patients treated with interferon beta achieve and maintain a full response to the drug over time, although an additional small number of individuals may still restore an optimal response to the drug after an initial failure.