Korean J Radiol.  2001 Jun;2(2):63-67. 10.3348/kjr.2001.2.2.63.

Hippocampal Sclerosis: Correlation of MR Imaging Findings

• Kim YH
• Chang KH
• Park SW
• Ko YW
• Lee SH
• Yu IK
• Han MH
• Lee SK
• Chung CK

• KMID: 754106
• DOI: http://doi.org/10.3348/kjr.2001.2.2.63

Abstract

OBJECTIVE
Atrophy and a high T2 signal of the hippocampus are known to be the principal MR imaging findings of hippocampal sclerosis. The purpose of this study was to determine whether or not individual MRI findings correlate with surgical outcome in patients with this condition. MATERIALS AND METHODS: Preoperative MR imaging findings in 57 consecutive patients with pathologically-proven hippocampal sclerosis who underwent anterior temporal lobectomy and were followed-up for 24 months or more were retrospectively reviewed, and the results were compared with the postsurgical out-come (Engel classification). The MR images included routine sagittal T1-weighted and axial T2-weighted spin-echo images, and oblique coronal T1-weighted 3D gradient-echo and T2-weighted 2D fast spin-echo images obtained on either a 1.5 T or 1.0 T unit. The images were visually evaluated by two neuroradiologists blinded to the outcome; their focus was the presence or absence of atrophy and a high T2 hippocampal signal. RESULTS: Hippocampal atrophy was seen in 96% of cases (55/57) [100% (53/53) of the good outcome group (Engel class I and II), and 50% (2/4) of the poor outcome group (class III and IV)]. A high T2 hippocampal signal was seen in 61% of cases (35/57) [62% (33/53) of the good outcome group and 50% (2/4) of the poor outcome group]. All 35 patients with a high T2 signal had hippocampal atrophy. `Normal' hippocampus, as revealed by MR imaging, occurred in 4% of patients (2/57), both of whom showed a poor outcome (Engel class III). The presence or absence of hippocampal atrophy correlated well with surgical outcome (p<0.01). High T2 signal intensity did not, however, significantly correlate with surgical outcome (p>0.05). CONCLUSION: Compared with a high T2 hippocampal signal, hippocampal atrophy is more common and correlates better with surgical outcome. For the prediction of this, it thus appears to be the more useful indicator.

Keyword

Brain, epilepsy; Brain, magnetic resonance; Hippocampal sclerosis

MeSH Terms

Adult
Atrophy
Female
Hippocampus/*pathology/*surgery
Human
*Magnetic Resonance Imaging
Male
Middle Age
Predictive Value of Tests
Retrospective Studies
Sclerosis
Support, Non-U.S. Gov't
Treatment Outcome

Figure

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  Fig. 1 Example of severe hippocampal atrophy. Oblique coronal T2-weighted MR image shows shows severe atrophy, with increased signal intensity in right hippocampus (arrow). The patient's outcome was Engel class I.

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  Fig. 2 Example of mild hippocampal atrophy. Oblique coronal T2-weighted MR image shows mild atrophy, with increased signal intensity in right hippocampus (arrow). The patient's outcome was Engel class IV.

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  Fig. 3 Example of normal-appearing hippocampus in an Engel class III patient. Oblique coronal T2-weighted MR image shows no definite evidence of hippocampal abnormality.

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