Effect of slice thickness on brain magnetic resonance image texture analysis.

BACKGROUND: The accuracy of texture analysis in clinical evaluation of magnetic resonance images depends considerably on imaging arrangements and various image quality parameters. In this paper, we study the effect of slice thickness on brain tissue texture analysis using a statistical approach and classification of T1-weighted images of clinically confirmed multiple sclerosis patients. METHODS: We averaged the intensities of three consecutive 1-mm slices to simulate 3-mm slices. Two hundred sixty-four texture parameters were calculated for both the original and the averaged slices. Wilcoxon's signed ranks test was used to find differences between the regions of interest representing white matter and multiple sclerosis plaques. Linear and nonlinear discriminant analyses were applied with several separate training and test sets to determine the actual classification accuracy. RESULTS: Only moderate differences in distributions of the texture parameter value for 1-mm and simulated 3-mm-thick slices were found. Our study also showed that white matter areas are well separable from multiple sclerosis plaques even if the slice thickness differs between training and test sets. CONCLUSIONS: Three-millimeter-thick magnetic resonance image slices acquired with a 1.5 T clinical magnetic resonance scanner seem to be sufficient for texture analysis of multiple sclerosis plaques and white matter tissue.

Computed tomography-based tumor volume in non-Hodgkin lymphoma: clinical correlation and comparison with magnetic resonance imaging.

OBJECTIVES: To evaluate the prognostic significance of tumor volume in computed tomographic (CT) images of non-Hodgkin lymphoma patients. To compare CT volumes with those measured by magnetic resonance imaging (MRI). METHODS: Twenty-five patients with B cell-type non-Hodgkin lymphoma (16 men, 9 women, age range, 48-77 years) were imaged with CT at 5 time points. The volumes and volume reductions were associated with clinical characteristics and treatment outcome. The CT-derived tumor volumes were correlated with MRI volumes derived earlier for the same patients. RESULTS: Good agreement was found between 1-dimensional (1D), 2D, and 3D analyses. The CT-derived median tumor volumes were 306 cm, 174 cm, 75 cm, 28 cm, and 15 cm at the 5 time points. These volumes were found to associate, for example, with mortality and tumor malignancy. The CT-based tumor volumes showed good correlation with MRI. CONCLUSIONS: Tumor volume quantification is a powerful tool that associates with clinical characteristics and treatment outcome.

Non-Hodgkin lymphoma response evaluation with MRI texture classification.

BACKGROUND: To show magnetic resonance imaging (MRI) texture appearance change in non-Hodgkin lymphoma (NHL) during treatment with response controlled by quantitative volume analysis. METHODS: A total of 19 patients having NHL with an evaluable lymphoma lesion were scanned at three imaging timepoints with 1.5T device during clinical treatment evaluation. Texture characteristics of images were analyzed and classified with MaZda application and statistical tests. RESULTS: NHL tissue MRI texture imaged before treatment and under chemotherapy was classified within several subgroups, showing best discrimination with 96% correct classification in non-linear discriminant analysis of T2-weighted images.Texture parameters of MRI data were successfully tested with statistical tests to assess the impact of the separability of the parameters in evaluating chemotherapy response in lymphoma tissue. CONCLUSION: Texture characteristics of MRI data were classified successfully; this proved texture analysis to be potential quantitative means of representing lymphoma tissue changes during chemotherapy response monitoring.

Response analysis of non-hodgkin lymphoma using magnetic resonance imaging-based volumes.

OBJECTIVE: The aim of this study was to determine the volume of non-Hodgkin lymphomas (NHLs) using semiautomatic segmentation and to correlate these results with clinical findings, treatment, and prognosis in patients with B-cell-type NHL. METHODS: For this study, 29 patients with NHL underwent magnetic resonance imaging at 5 time points after onset of disease. Volumetric analysis of the tumors was accomplished with semiautomatic segmentation by the Anatomatic software. RESULTS: The median tumor volumes from the first to the fifth examination were 468, 256, 90, 38, and 33 cm. Good correlation with 1-dimensional and 2-dimensional measures, used as standard methods in response categorization, was found. Surprisingly, volume reductions in excess of 239 cm after only 1 week of chemotherapy decreased the survival probability. CONCLUSIONS: Volume measurements seem to be highly informative for prognosis in the very early stages of treatment for patients with NHL.

Increased serum matrix metalloproteinase 9 levels in systemic lupus erythematosus patients with neuropsychiatric manifestations and brain magnetic resonance imaging abnormalities.

OBJECTIVE: To evaluate whether serum matrix metalloproteinase 9 (MMP-9) levels are associated with neuropsychiatric manifestations, particularly cognitive dysfunction, as evaluated by neuropsychological testing and brain magnetic resonance imaging (MRI) abnormalities in patients with systemic lupus erythematosus (SLE). METHODS: MMP-9 determinations were made in 44 patients with SLE and 43 healthy controls who underwent a clinical neurologic and neuropsychological investigation in order to identify neuropsychiatric manifestations. Cerebral MRI scans with volumetric estimation of intracranial cerebrospinal fluid spaces, T1-weighted lesions, and T2-weighted lesions were performed for all subjects. SLE activity was assessed by the European Consensus Lupus Activity Measure (ECLAM) index, and accumulated neuropsychiatric abnormality was assessed by the Systemic Lupus International Collaborating Clinics (SLICC)/American College of Rheumatology damage index. RESULTS: No significant difference was found in serum MMP-9 levels between the overall group of SLE patients and controls. However, SLE patients who had at least 1 neuropsychiatric manifestation (NPSLE patients) had significantly higher serum MMP-9 concentrations than did SLE patients without neuropsychiatric syndromes (P = 0.009). Among patients with NPSLE, those with cognitive deficits had significantly higher concentrations of serum MMP-9 than did those with normal cognitive function (P = 0.027). Furthermore, serum MMP-9 levels had a significant positive correlation with the volumes of T1-weighted and T2-weighted lesions in the brain MRI (P = 0.031 and P = 0.015, respectively). The concentration of serum MMP-9 correlated significantly with the SLICC index but not with the ECLAM index. CONCLUSION: Elevated levels of serum MMP-9 in patients with SLE may reflect neuropsychiatric involvement, particularly cognitive dysfunction. The serum MMP-9 concentration may be associated with small- vessel cerebral vasculopathy and increased risk of cerebral ischemic events in patients with SLE.