Imaging of Patients with Hippocampal Sclerosis at 7 Tesla: Initial Results

Breyer, Tobias; Wanke, Isabel; Maderwald, Stefan; Woermann, Friedrich G.; Kraff, Oliver; Theysohn, Jens M.; Ebner, Alois; Forsting, Michael; Ladd, Mark E.; Schlamann, Marc

doi:10.1016/j.acra.2009.10.013

« Previous Next »Academic Radiology
Volume 17, Issue 4 , Pages 421-426, April 2010

Imaging of Patients with Hippocampal Sclerosis at 7 Tesla:

Initial Results

Tobias Breyer, MD
- Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen University Hospital, Hufelandstr. 55, D-45122 Essen, Germany
- Address correspondence to: T.B.
Isabel Wanke, MD
- Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen University Hospital, Hufelandstr. 55, D-45122 Essen, Germany
Stefan Maderwald, PhD
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
Friedrich G. Woermann, MD
- MRI and Klinik Mara, Bethel Epilepsy Center, Bielefeld, Germany
Oliver Kraff, PhD
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
Jens M. Theysohn, MD
- Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen University Hospital, Hufelandstr. 55, D-45122 Essen, Germany
Alois Ebner, MD
- MRI and Klinik Mara, Bethel Epilepsy Center, Bielefeld, Germany
Michael Forsting, MD
- Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen University Hospital, Hufelandstr. 55, D-45122 Essen, Germany
Mark E. Ladd, PhD
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
Marc Schlamann, MD
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany

Received 13 September 2009; accepted 7 October 2009. published online 17 December 2009.

Rationale and Objectives

Focal epilepsies potentially can be cured by neurosurgery; other treatment options usually remain symptomatic. High-resolution magnetic resonance (MR) imaging is the central imaging strategy in the evaluation of focal epilepsy. The most common substrate of temporal epilepsies is hippocampal sclerosis (HS), which cannot always be sufficiently characterized with current MR field strengths. Therefore, the purpose of our study was to demonstrate the feasibility of high-resolution MR imaging at 7 Tesla in patients with focal epilepsy resulting from a HS and to improve image resolution at 7 Tesla in patients with HS.

Materials and Methods

Six patients with known HS were investigated with T1-, T2-, T2^∗-, and fluid-attenuated inversion recovery–weighted sequences at 7 Tesla with an eight-channel transmit-receive head coil. Total imaging time did not exceed 90 minutes per patient.

Results

High-resolution imaging at 7 Tesla is feasible and reveals high resolution of intrahippocampal structures in vivo. HS was confirmed in all patients. The maximum non-interpolated in-plane resolution reached 0.2 × 0.2 mm² in T2^∗-weighted images. The increased susceptibility effects at 7 Tesla revealed identification of intrahippocampal structures in more detail than at 1.5 Tesla, but otherwise led to stronger artifacts. Imaging revealed regional differences in hippocampal atrophy between patients. The scan volume was limited because of specific absorption rate restrictions, scanning time was reasonable.

Conclusions

High-resolution imaging at 7 Tesla is promising in presurgical epilepsy imaging. “New” contrasts may further improve detection of even very small intrahippocampal structural changes. Therefore, further investigations will be necessary to demonstrate the potential benefit for presurgical selection of patients with various lesion patterns in mesial temporal epilepsies resulting from a unilateral HS.

Key Words: High resolution MRI, 7 Tesla, hippocampal sclerosis, human