Hippocampal volume assessment in temporal lobe epilepsy: How good is automated segmentation?
OBJECTIVE
Quantitative measurement of hippocampal volume using structural magnetic resonance imaging (MRI) is a valuable tool for detection and lateralization of mesial temporal lobe epilepsy with hippocampal sclerosis (mTLE). We compare two automated hippocampal volume methodologies and manual hippocampal volumetry to determine which technique is most sensitive for the detection of hippocampal atrophy in mTLE.


METHODS
We acquired a three-dimensional (3D) volumetric sequence in 10 patients with left-lateralized mTLE and 10 age-matched controls. Hippocampal volumes were measured manually, and using the software packages Freesurfer and FSL-FIRST. The sensitivities of the techniques were compared by determining the effect size for average volume reduction in patients with mTLE compared to controls. The volumes and spatial overlap of the automated and manual segmentations were also compared.


RESULTS
Significant volume reduction in affected hippocampi in mTLE compared to controls was detected by manual hippocampal volume measurement (p < 0.01, effect size 33.2%), Freesurfer (p < 0.01, effect size 20.8%), and FSL-FIRST (p < 0.01, effect size 13.6%) after correction for brain volume. Freesurfer correlated reasonably (r = 0.74, p << 0.01) with this manual segmentation and FSL-FIRST relatively poorly (r = 0.47, p << 0.01). The spatial overlap between manual and automated segmentation was reduced in affected hippocampi, suggesting the accuracy of automated segmentation is reduced in pathologic brains.


CONCLUSIONS
Expert manual hippocampal volumetry is more sensitive than both automated methods for the detection of hippocampal atrophy associated with mTLE. In our study Freesurfer was the most sensitive to hippocampal atrophy in mTLE and could be used if expert manual segmentation is not available.
Pardoe
Heath R
HR
Brain Research Institute, Florey Neuroscience Institutes (Austin), Melbourne, Victoria, Australia.
Pell
Gaby S
GS
Abbott
David F
DF
Jackson
Graeme D
GD
D000328:Adult; D001284:Atrophy / Q000145:classification / Q000473:pathology; D001921:Brain / Q000473:pathology; D001931:Brain Mapping / Q000379:methods; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis / Q000473:pathology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000706:statistics & numerical data*; D008297:Male; D012598:Sclerosis / Q000473:pathology
AJNR Am J Neuroradiol. 1993 May-Jun;14(3):753-62
8517369
Neurology. 1995 Dec;45(12):2233-40
8848199
Psychiatry Res. 2000 Aug 28;99(2):93-110
10963985
Epilepsia. 2009 Feb;50(2):228-33
18727679
Neurology. 1998 Jul;51(1):66-71
9674780
J Comput Assist Tomogr. 1993 Mar-Apr;17(2):206-10
8454746
Ann Neurol. 1993 Dec;34(6):795-801
8250528
Radiology. 1990 May;175(2):423-9
2183282
Neuroimage. 2007 May 15;36(1):38-47
17428687
Arch Neurol. 2004 Sep;61(9):1379-84
15364683
Neurology. 2004 Dec 28;63(12):2303-8
15623691
Neurology. 1992 Sep;42(9):1743-50
1513464
Epilepsy Res. 2008 May;79(2-3):130-8
18359198
Neuroimage. 2004 Sep;23(1):318-24
15325379
Epilepsia. 1997 May;38(5):576-87
9184604
Neuroimage. 2009 Apr 15;45(3):855-66
19162198
Hum Brain Mapp. 2002 Nov;17(3):143-55
12391568
Brain. 2003 Feb;126(Pt 2):462-9
12538412
Radiology. 2000 Jul;216(1):291-7
10887264
Philos Trans R Soc Lond B Biol Sci. 2001 Aug 29;356(1412):1293-322
11545704
J Neurol Neurosurg Psychiatry. 2002 Dec;73(6):648-55
12438464
Brain. 1992 Aug;115 ( Pt 4):1001-15
1393499
Med Image Comput Comput Assist Interv. 2007;10(Pt 1):875-82
18051141
Neuroimage. 2008 Feb 1;39(3):1151-61
18042496
Ann Neurol. 1991 Jul;30(1):31-6
1929226
Neuron. 2002 Jan 31;33(3):341-55
11832223
Epilepsia. 1998 Nov;39(11):1174-81
9821981
Brain. 2004 Aug;127(Pt 8):1731-40
15231583
Magn Reson Imaging. 2000 Dec;18(10):1187-99
11167039