T2 Relaxometry within 5 Days of Prolonged Febrile Convulsion.
Abstract number :
2.198
Submission category :
Year :
2001
Submission ID :
291
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
R.C. Scott, PhD MRCP, Neurosciences/Radiology and Physics Units, Institute of Child Health, London; D.G. Gadian, DPhil, Radiology and Physics Unit, Institute of Child Health, London; B.G. Neville, FRCP, Neurosciences Unit, Institute of Child Health, Londo
RATIONALE: The relationship between prolonged febrile convulsion (PFC) and subsequent mesial temporal sclerosis (MTS) has long been recognised, but it is still uncertain whether PFC causes MTS or whether MTS is present at the time of PFC. The aim of this study was to use high resolution qualitative and quantitative MRI to assess whether there is any visual evidence of MTS and whether PFC is associated with abnormalities in hippocampal T2 relaxation time, within 5 days of the acute event, when compared to controls.
METHODS: 11 children with a history of PFC and 6 controls were enrolled. All underwent magnetic resonance investigations including conventional epilepsy imaging (T2-weighted axial and coronal imaging, and T1-weighted 3D-dataset reformatted at 90 degrees to the long axis of the hippocampus), quantitative T2 relaxometry (T2) using a modified CPMG sequence, hippocampal volumetry, diffusion weighted imaging and perfusion imaging. Visual assessment of conventional imaging and T2 findings are reported here, (analysis of the other investigations is ongoing). Multiple linear regression was used for statistical analysis. Ratio of higher to lower T2 (T2 ratio) in each individual was compared between groups (Mann-Whitney U).
RESULTS: Median age of the controls was 15 (interquartile range, 7-23) months and of the patients was 20 (13-27) months. The patients had a median seizure length of 45 (range, 30-245) minutes. No hippocampal abnormalities were identified on visual assessment of the imaging, in particular there was no evidence of MTS. Quantitative T2 was dependent upon age (p[lt]0.001) and on the history of PFC (p=0.029). It was not dependent upon seizure length or time from PFC to investigation. T2 was prolonged by a mean of 8.1ms (95% CI; 1.0-15.3ms) when compared to controls. T2 ratio was similar in patient and control groups (p=0.33).
CONCLUSIONS: No evidence of MTS was identified visually. Symmetrical prolongation of T2 in this context is unlikely to be due to MTS and therefore may reflect hippocampal oedema. Follow-up studies are required to determine whether any of these patients develop MTS.
Support: The Wellcome Trust