Centrally Reduced Diffusion Sign for Differentiation between Treatment-Related Lesions and Glioma Progression: A Validation Study.

BACKGROUND AND PURPOSE: Differentiating between treatment-related lesions and tumor progression remains one of the greatest dilemmas in neuro-oncology. Diffusion MR imaging characteristics may provide useful information to help make this distinction. The aim of the study was to assess the diagnostic accuracy of the centrally reduced diffusion sign for differentiation of treatment-related lesions and true tumor progression in patients with suspected glioma recurrence. MATERIALS AND METHODS: The images of 231 patients who underwent an operation for suspected glioma recurrence were reviewed. Patients with susceptibility artifacts or without central necrosis were excluded. The final diagnosis was established according to histopathology reports. Two neuroradiologists classified the diffusion patterns on preoperative MR imaging as the following: 1) reduced diffusion in the solid component only, 2) reduced diffusion mainly in the solid component, 3) no reduced diffusion, 4) reduced diffusion mainly in the central necrosis, and 5) reduced diffusion in the central necrosis only. Diagnostic accuracy metrics and the area under the receiver operating characteristic curve were estimated for the diffusion patterns. RESULTS: One hundred three patients were included (22 with treatment-related lesions and 81 with tumor progression). The diagnostic accuracy results for the centrally reduced diffusion pattern as a predictor of treatment-related lesions ("mainly central" and "exclusively central" patterns versus all other patterns) were as follows: 64% sensitivity (95% CI, 41%-83%), 84% specificity (95% CI, 74%-91%), 52% positive predictive value (95% CI, 37%-66%), and 89% negative predictive value (95% CI, 83%-94%). CONCLUSIONS: The centrally reduced diffusion sign is associated with the presence of treatment effect. The probability of a histologic diagnosis of a treatment-related lesion is low (11%) in the absence of centrally reduced diffusion.

A longitudinal study of ventricular volume in early relapsing-remitting multiple sclerosis.

The specific aim of this study was to determine whether progressive brain atrophy could be detected within 18 months of establishing a diagnosis of relapsing-remitting multiple sclerosis (RRMS). Fifteen patients with clinically definite RRMS (mean disease duration from first symptom=6 months, mean EDSS=1.2) completed 6 - 14 monthly quantitative MRI sessions. The volume of the lateral ventricles was determined each month using a semi-automated thresholding technique from T1-weighted axial images. The number of new monthly gadolinium-enhancing (Gd+) lesions and EDSS scores were also recorded. Lateral ventricular volumes increased significantly during this study. When individual data were examined, statistically significant changes were observed in six of 15 patients. Monthly change in ventricular volume was related to baseline EDSS and total number of new Gd(+) lesions. These observations indicate brain atrophy, a putative imaging marker of diffuse demyelination and axonal loss, can occur as early as 18 months after first symptoms of RRMS, and is related to the baseline level of disability and to the number of new Gd+ lesions. Multiple Sclerosis (2000) 6 332 - 337

Hemispheric involvement in the perception of syntactic prosody is dynamically dependent on task demands.

The first aim of this study was to determine if there was a significant perceptual asymmetry for syntactic prosody and if it differed from the perceptual asymmetry for emotional prosody. The second aim of this study was to determine if the observed asymmetries were the product of task demands or stimulus features. Experiment 1 consisted of a Syntactic task and an Emotional task. In the Syntactic task, subjects identified Statement and Question prosody in dichotically presented sentences. In the Emotional task, subjects identified Angry and Sad prosody in dichotically presented sentences. There was a significant left ear advantage for the Emotional task and no significant ear advantage for the Syntactic task. In Experiment 2, subjects had to perform an Emotional prosody task with the syntactic Statement and Question prosody stimuli from Experiment 1. There was a significant left ear advantage, indicating that the perceptual asymmetry was determined by task demands and not stimulus features.