American Journal of Roentgenology Neuroradiology

[Neuroradiology] Potential Role of Diffusion Tensor MRI in the Differential Diagnosis of Mild Cognitive Impairment and Alzheimer's Disease

2008-04-22

OBJECTIVE. The purpose of this study was to evaluate the fractional anisotropy values of several white matter tracts with the aim of differentiating a healthy population from persons with mild cognitive impairment or Alzheimer's disease.

SUBJECTS AND METHODS. Seventy-nine patients with memory impairment and 16 volunteer controls participated in the study. MRI was performed with a 1.5-T system. Conventional MR images and diffusion tensor images were obtained for all participants. The diffusion tensor imaging data were postprocessed, and low b-value, fractional anisotropy, and fractional anisotropy color-coded maps were calculated. With the three maps as an anatomic reference, fractional anisotropy was measured for hippocampal formations, superior longitudinal fascicles, posterior cingulate gyri, and the splenium of the corpus callosum. Kruskal-Wallis and Steel-type multiple-comparison nonparametric tests were performed for the statistical analysis.

RESULTS. The fractional anisotropy values for the splenium of the corpus callosum, bilateral posterior cingulate gyri, and bilateral superior longitudinal fascicles of patients with mild cognitive impairment and those with probable Alzheimer's disease were significantly lower than the values of controls. No differences were found in hippocampal formations in any group. No significant difference was found in fractional anisotropy values in comparisons of mild cognitive impairment versus possible Alzheimer's disease and probable Alzheimer's disease or comparisons of probable Alzheimer's disease and possible Alzheimer's disease.

CONCLUSION. Diffusion tensor imaging is a promising technique for the evaluation of patients with probable mild cognitive impairment. Early detection of the disease expands the treatment options, increasing the likelihood of a good clinical response and enhancing the quality of life of patients and their relatives. Further studies with larger populations are needed to confirm the role of diffusion tensor imaging in the evaluation of memory impairment.

[Neuroradiology] Neuroimaging of Tuberous Sclerosis: Spectrum of Pathologic Findings and Frontiers in Imaging

Kalantari, B. N., Salamon, N. — 2008-04-22

OBJECTIVE. The purpose of this article is to present neuroimaging findings in tuberous sclerosis complex, including recently developed imaging techniques that have demonstrated clinical benefit to this patient population.

CONCLUSION. Neuroimaging advances have improved the diagnosis of tuberous sclerosis complex and the treatment of children with this condition. Superimposition of functional information from PET onto MRI allows accurate and noninvasive identification of epileptogenic tubers, improving surgical cure rates. Magnetic source imaging can also be used to localize epileptiform activity arising from tubers.

[Neuroradiology] Midterm Results of Percutaneous CT-Guided Aspiration of Symptomatic Lumbar Discal Cysts

Kang, H., Liu, W. C., Lee, S.-H., Paeng, S. S. — 2008-04-22

OBJECTIVE. Lumbar intervertebral discal cysts are rarely reported. To our knowledge, only 12 cases have been reported in the literature. The symptoms are indistinguishable from those of typical discal herniation. Our aim is to report the imaging characteristics, method of percutaneous CT-guided aspiration, and clinical outcome after management of lumbar intervertebral discal cysts.

CONCLUSION. Percutaneous CT-guided aspiration is an effective method for the management of lumbar intervertebral discal cysts.

[Neuroradiology] Hippocampal MRI Signal Hyperintensity After Febrile Status Epilepticus Is Predictive of Subsequent Mesial Temporal Sclerosis

2008-03-20

OBJECTIVE. The objective of our study was to test the hypothesis that the finding of hyperintense hippocampal signal intensity on T2-weighted MR images soon after febrile status epilepticus is associated with subsequent hippocampal volume loss and persistent abnormal signal intensity on T2-weighted images (i.e., mesial temporal sclerosis).

SUBJECTS AND METHODS. Eleven children (mean age, 25 months) underwent initial MRI that included coronal temporal lobe imaging within 72 hours of febrile status epilepticus and follow-up imaging from 3 to 23 months later (mean, 9 months). A neuroradiologist blinded to clinical history graded initial and follow-up hippocampal signal intensity on a scale from 0 (normal) to 4 (markedly increased). Two blinded observers measured hippocampal volumes on initial and follow-up MR studies using commercially available software and volumes from 30 healthy children (mean age, 6.3 years). Initial signal intensity and hippocampal volume changes were compared using Kendall tau correlation coefficients.

RESULTS. On initial imaging, hyperintense signal intensity ranging from 1 (minimally increased) to 4 (markedly increased) was seen in seven children. Four children had at least one hippocampus with moderate or marked signal abnormality, three children had a hippocampus with mild or minimal abnormality, and four children had normal signal intensity. The Kendall tau correlation coefficient between signal intensity increase and volume change was –0.68 (p < 0.01). Five children (two with temporal lobe epilepsy and two with complex partial seizures) had hippocampal volume loss and increased signal intensity on follow-up imaging, meeting the criteria for mesial temporal sclerosis.

CONCLUSION. MRI findings of a markedly hyperintense hippocampus in children with febrile status epilepticus was highly associated with subsequent mesial temporal sclerosis.