3T MR SPECTROSCOPY IN DRUG-RESISTANT TEMPORAL LOBE EPILEPSY WITH HIPPOCAMPAL ABNORMALITIES S. Battaglia1, A.F. Marliani1, F.Toni1, L.Albini Riccioli1, V. Clementi2, G. Rubboli3, P. Agati4, R. Agati1, M. Leonardi1 1 Neuroradiology Department, Bellaria Hospital, Bologna, Italy 2 GE Healthcare Technologies, GE Healthcare, Bologna, Italy 3 Neurology Department, Bellaria Hospital, Bologna, Italy 4 Department of Statistics, University of Bologna, Italy 1

The most common cause of temporal lobe epilepsy (TLE: 80% of partial epilepsies) is hippocampal sclerosis, followed by cortical dysplasia, from migration and gyration abnormalities, tumors, etc. The MRI study is crucial to identify the presence or absence of morphological and/or signal abnormalities, particularly in cases of drug-resistant epilepsy (20-30%), in which surgical therapy can be resolutive

Single voxel MR Spectroscopy 1H-MRS can complete the morphological MRI study to identify metabolic abnormalities in patients affected by cryptogenic or symptomatic TLE. In both cases, metabolic abnormalities have been described either in the side identified as "pathological" with electrophysiological and morphological examinations, and in the contralateral one

We selected 20 patients (9 ♂ 11 ♀, mean age 39 +/- 7 ys) with drug- resistant TLE surgical candidates MRI study showed temporal lobe tissue morphological and/or signal abnormality (not tumoral) in one side (13 right and 7 left), concordant with the one suggested by clinical and electrophysiological data (almost all MTS +/- suspected dysplasia of the pole). All patients undergone surgical treatment. Histological examination confirmed classic/global type Ammon’s horn sclerosis, archit./cytoarchitettural temporal pole cortical dysplasia or microdysgenetic aspects.

MTS Right side MTS DX

3T MR Protocol Morphological examination FSPGR T1 3D and MPR Reformatted Axial FSE DP e T2 Coronal FLAIR T2 Coronal FSE-IR Coronal GRE T2* 1H-MRS on bilateral hippocampal regions TE 35 ms TR 2000 ms 128 NEX 5’ 04’’ Acquisition VOI min 1.3 cm3 - max 5.9 cm3 Data post-processing was performed by using LC-Model

Axial sequences are acquired in parallel to the course of the temporal horns and the coronal ones perpendicular to it. Rectangular VOI along the hippocampus, to minimize artifacts due to the adjacent tissue. The tNAA/Cr, tNAA/Cho, tCho/Cr, mI/Cr, Glx/Cr ratio were calculated and compared with data collected from 12 healthy volunteers (8 ♀ and 4 ♂, mean age 39 +/- 10)

1299.5 p < 0.001   (p = 0.0001298)  1062 NN (p = 0.000256)‏ 996.5 mI/Cr Pathological Hippocampus Vs Contralateral Contralateral Hippocampus controls Pathological Hippocampus Vs  controls 2.55 p < 0.05   (p = 0.01372) 3.20 (p = 0.000762) 3.37 tNAA/Cho tCho/Cr Glx/Cr 913.5 p < 0.01   (p = 0.005581) 1063.5 p < 0.05  (p = 0.04824) 1198.5 (p = 0.000253) tNAA/Cr Statistical analysis (two-sample Wilcoxon rank sum test, equivalent to the Mann-Whitney test) Median values

Right pathological tNAA mI control tNAA control Left contralateral

Over the past 15 years over 6000 works have been published on this topic. The results described are in part contradictory, possibly due either to the use of different 1.5 T MRI equipments or to the different procedures of analysis. By working with a 3T system, our aim was to study epileptic patients in the hope that the greater power of the magnet could give us more accurate and consistent results..

…. our results don’t show a statistically significant differences in comparison with controls in literature, however, its increase is related to epileptic activity (increase in the epileptogenic focus, mainly in cryptogenic TLE) of Glx/Cr ratio in both the pathological side and in the contralateral one Woermann FG Ann Neurol 1999 Petroff OA Seizure 1999 Simister RJ Epilepsya 2002 Riederer F NMR Biomed 2006 Doelken MT Seizure 2008 Simister JR Epilepsy Research 2009 of tCho/Cr ratio in both the pathological side and in the contralateral hippocampus increased tCho/Cr has been described by other authors, and it was interpreted as a sign of cell membranes damage Urenjak J Journal Neurosci 1993 Connely A Neurology 1994 Achten E Am J Neuroradiol 1997 Simister RJ Epilepsya 2002 Hammen T Eur J Neurol 2006 Doelken MT Seizure 2008

…. our results confirm a decrease of tNAA/Cr ratio in the pathological hippocampus as compared to the contralateral and to controls Neuronal depletion (confirmed histologically)  Abnormal functionality Hugg JW Ann Neurol 1993 Cendes F Ann Neurol 1994 Connely A Neurology 1994 Kuzniecky R Neurology 1998 Doelken MT Seizure 2008 SmisterJR Epilepsy research 2009 a decrease of tNAA/Cr ratio on contralateral hippocampus compare to controls Abnormal functionality (extension of the disease? Prognostic significance? reversibility?)‏ Woermann FG Ann Neurol 1999 SmisterJR Epilepsya 2002 Mueller SG Epilepsya 2004 Hajek M Eur radiol 2009

…. our results indicate in all patients a statistically significant increase (p<0.01) of the mI/Cr ratio as a characteristic feature of the pathological side compared to contralateral hyppocampus and to controls gliosis (confirmed histologically) induction of the cotransporter Na+/mI after epileptic activity Mueller SG Epilepsya 2003 Wellard Epilepsya 2003 Riederer NMR 2006 This finding, if properly confirmed, may help a correct lateralization

…. our next step tNAA tNAA to study, in patient treated with surgical resection of the pathological hyppocampus, metabolite modification of the contralateral side, compared to pre-op results tNAA

Conclusions In the drug-resistant temporal lobe epilepsy 1H-MRS identifies statistically significant alterations in both the hippocampi side to be treated surgically The histological diagnosis reflects the metabolic abnormalities identified 1H-MRS can be used to monitor patients undergoing surgery

Thank you for your kind attention

Istologia RM TLE età, ♀/♂ Pz. Focale deplezione neuronale ippocampo, microdisgenesia polo STM sn 49, ♀ 20 Sclerosi corno Ammone tipo classico, displasia cort. architetturale STM, displ. e atrofia polo dx 33, ♀ 19 STM, lieve atrofia polo 36, ♂ 18 meningoencefalocele ala sferoidale sx, microdisgenesia del polo e gliosi ippocampo Les pluricistica con malf. grande ala sfenoide, iposviluppo polo temporale 17 Sclerosi corno Ammone tipo globale, displasia cort. architetturale 32, ♀ 16 Displasia cort. cito-architetturale del polo Dubbia displasia polo-uncus 30, ♀ 15 Sclerosi corno Ammone tipo classico, displasia cort. citoarchitetturale, lesione amartomatosa glio-neuronale STM, sosp. displasia polo 38, ♀ 14 Sclerosi corno Ammone, displasia corticale architetturale del polo sx 13 41, ♀ 12 Sclerosi corno Ammone tipo globale, microdisgenesia del polo 27, ♂ 11 45, ♂ 10 Sclerosi corno Ammone tipo classico, microdisgenesia del polo STM, atrofia polo 36, ♀ 9 STM, Δ segnale sn 44, ♂ 8 Sclerosi corno Ammone tipo classico, displasia cort.citoarchitetturale STM sn, Δ segnale dx 46, ♀ 7 Sclerosi corno Ammone tipo classico, displasia cort. architetturale 6 5 Sclerosi corno Ammone tipo classico 4 35, ♀ 3 STM, displasia polo 55, ♂ 2 1 Istologia RM TLE età, ♀/♂ Pz.

Candidati alla chirurgia: epilessia grave (per frequenza e handicap psico-sociale e professionale)‏ farmaco-resistente: dopo un minimo di 2 anni di trattamento zona epilettogena stabile e unica possibilità di exeresi chirurgica che non determini deficit neurologici o neuropsicologici.

Follow-Up Data intervento Classe età, ♀/♂ Pz. 12 Maggio 2006 7 Settembre 2007 2 Novembre 2007 9 Ottobre 2007 16 Dicembre 2005 2 Febbraio 2007 16 Marzo 2007 19 Ottobre 2007 25 Gennaio 2008 3 Novembre 2006 13 Settembre 2006 16 Aprile 2008 13 Gennaio 2006 29 Maggio 2008 3 Ottobre 2006 28 Novembre 2007 27 Aprile 2007 2 Ottobre 2007 11 Marzo 2008 13 Dicembre 2007 Data intervento 2b 49, ♀ 20 33, ♀ 19 36, ♂ 18 17 1b 32, ♀ 16 1a 30, ♀ 15 38, ♀ 14 13 41, ♀ 12 27, ♂ 11 2a 45, ♂ 10 36, ♀ 9 44, ♂ 8 46, ♀ 7 6 5 4 35, ♀ 3 55, ♂ 2 1 Classe età, ♀/♂ Pz. Classification of seizure outcome Seizure freedom outcome was assessed at the last follow-up with at least 1 year elapsing before the final evaluation and according to Engel’s classification (Engel, 1987). The first subgroup, Engel’s class Ia, consisted of patients who reported no seizures after their surgery. The second subgroup, Engel’s class I, included both seizure free patients and those who have experienced simple partial seizures, or “brief auras” and “neighborhood” seizures and drug-withdrawal seizures. The third subgroup, Engel’s class II patients, included patients who were not seizure-free but had a substantial improvement, exhibiting still only rare seizures. The fourth subgroup, Engel’s class III–IV patients, included patients with frequent seizures and a truly unsatisfactory outcome. We separated four categories of patients according to – the seizure freedom with two definitions: o patients who were completely seizure-free after surgery (Engel’s class Ia patients) o those that had been free from seizures for at least 1 year at the time of assessment – the persistence of seizures and the importance of the reduction in seizure frequency: o patients who had rare seizures (i.e., Engel’s class II patients) o patients with frequent and disabling seizures (i.e., Engel’s class III–IV patients). Engel J Jr. (1987) Outcome with respect to epileptic seizures. In Engel J Jr (Ed) Surgical treatment of the epilepsies. 2nd ed. Raven Press, New York, pp. 553–571. Engel JJ,Wiebe S, French J, Sperling M,Williamson P, Spencer D, Gumnit R, Zahn C,Westbrook E, Enos B. (2003) Practice parameter: temporal lobe and localized neocortical resections for epilepsy: report of the Quality Standards Subcommittee of the American Academy of Neurology, in association with the American Epilepsy Society and the American Association of Neurological Surgeons. Neurology 60:538–547. Engel JJ. (1996) Surgery for seizures. New England Journal of Medicine 334:647–652.

Ippocampo controlaterale Ippocampo controlaterale 2.2 +/- 0.4 2.2 +/- 0.5 2.2 +/- 0.8 Glx/Cr 1.1 +/- 0.2 1.4 +/- 0.2 1 +/- 0.3 mI/Cr 0.3 +/- 0.04 0.3 +/- 0.05 0.3 +/- 0.06 tCho/Cr 3 +/- 0.5 2.7 +/- 0.6 3.6 +/- 0.9 tNNA/Cho 1 +/- 0.2 Ippocampo controlaterale 0.9 +/- 0.2 Ippocampo patologico 1.2 +/- 0.2 Controlli tNAA/Cr Media +/- SD Ippocampo controlaterale Ippocampo patologico Controlli 2084,5 1299,5 357 2,55 913,5 2205 1062 363,5 3,20 1063,5 2382,5 996,5 344 3,37 1198,5 Glx/Cr mI/Cr tCho/Cr tNNA/Cho tNAA/Cr Mediana

Media +/- DS Media +/- DS Media +/- DS Controlli patologici 1,997 0,021 1,316 1,011 5,900 0,065 8,789 2,680   5 0,067 9 2 0,057 3,2 7 10 3,6 8 0,048 2,8 4 1,7 3,4 6 0,086 2,4 3,1 0,01 1,4 3 0,096 0,076 4,2 1,9 2,3 2,2 1,6 11 5,5 0,105 12 S/N FWHM LW volume  Media +/- DS 2,634 0,019 2,668 1,153 6,900 0,065 9,684 2,695   6 0,067 8 1,8 7 9 2,9 0,057 4,2 10 2,8 4 0,048 1,3 3,4 0,076 2,4 2,3 3,1 5 1,4 0,096 11 3,8 13 1,9 1,7 2,2 1,6 19 5,9 0,115 S/N FWHM LW volume 2,462 0,025 2,151 1,866 7,667 0,068 10,917 4,575  Media +/- DS   8 0,076 10 9,9 5 0,096 4,6 9 12 4,9 6 0,067 11 4,3 13 0,115 15 4,4 7 0,033 2,8 0,043 2,6 0,057 14 5,3 3,9 0,029 0,086 3,3 S/N FWHM LW volume Controlli patologici Controlaterali

Ippocampo controlaterale NN mI/Cr Ippocampo patologico Vs Ippocampo controlaterale Ippocampo controlaterale controlli Ippocampo patologico tNNA/Cho tCho/Cr Glx/Cr tNAA/Cr Analisi statistica

Ippocampo controlaterale Analisi statistica: Test t di Student ATTenzione su 12 pazienti 0.00066508 (p<0.01)‏ 0.222064477 0.00278617 (p<0.01)‏ mI/Cr Ippocampo patologico Vs Ippocampo controlaterale Ippocampo controlaterale controlli Ippocampo patologico 0.116494883 0.030525889 (p<0.05)‏ 0.003564292 (p<0.01)‏ tNNA/Cho 1 0.996401748 0.996623558 tCho/Cr 0,848864709 0,826739377 0,917377921 Glx/Cr 0.090444486 0.005160921 (p<0.01)‏ 0.000196105 (p<0.01)‏ tNAA/Cr Analisi statistica: Test t di Student

Analisi Statistica: dati significativi Misura di sintesi adoperata per ogni parametro: MEDIANA Test usato: two-sample Wilcoxon rank sum test (equivalente al Mann-Whitney test)‏ PATOLOGICO     NORMALE  NAA+NAAG/Cr  p < 0.001   (p = 0.000253)‏ 913.5 1198.5 p < 0.001   (p = 0.000762)‏ NAA+NAAG/Cho 2.55 3.37 p < 0.001   (p = 0.000256)‏ 996.5 mI/Cre   1299.5

Analisi Statistica: dati significativi Misura di sintesi adoperata per ogni parametro: MEDIANA Test usato: two-sample Wilcoxon rank sum test (equivalente al Mann-Whitney test)‏ CONTROLATERALE     NORMALE  NAA+NAAG/Cr p < 0.05   (p = 0.04824)‏ 1063.5 1198.5

Analisi Statistica: dati significativi Misura di sintesi adoperata per ogni parametro: MEDIANA Test usato: Wilcoxon matched-pairs signed rank test PATOLOGICO     CONTROLATERALE NAA+NAAG/Cre  913.5 p < 0.01   (p = 0.005581) 1063.5 NAA+NAAG/Cho 2.55 p < 0.05   (p = 0.01372) 3.20 mI/Cre   1299.5 p < 0.001  (p = 0.0001298)   996.5