Hippocampal T2 Relaxation Time Research Articles

Novel approach to magnetic resonance imaging of epileptic dogs - T2 relaxometry of the brain with emphasised hippocampus.

Hippocampal sclerosis is the most common imaging finding of intractable human epilepsy, and it may play an important role in canine and feline epileptogenesis and seizure semiology, too. The magnetic resonance imaging (MRI) criteria of hippocampal sclerosis are T2 hyperintensity, shrinkage and loss of internal structure. The detection of these changes is often challenging by subjective visual assessment of qualitative magnetic resonance (MR) images. The recognition is more reliable with quantitative MR methods, such as T2 relaxometry. In the present prospective study including 31 dogs with idiopathic epilepsy and 15 control dogs showing no seizure activity, we compared the T2 relaxation times of different brain areas. Furthermore, we studied correlations between the hippocampal T2 values and age, gender and skull formation. We found higher hippocampal T2 values in the epileptic group than in the control; however, these findings were not statistically significant. No correlations were found with age, gender or skull formation. In the individual analysis six epileptic dogs presented higher hippocampal T2 relaxation times than the cut-off value. Two of these dogs were also evaluated as abnormal in the visual assessment. Individual analysis of hippocampal T2 relaxation times may be a helpful method to understand hippocampal involvement in canine epilepsy.

Treatment of people at ultra-high risk for psychosis.

Treatment of people at ultra-high risk for psychosis.

Individual hippocampal subfield assessment indicates that matrix macromolecules and gliosis are key elements for the increased T2 relaxation time seen in temporal lobe epilepsy.

Increased T2 relaxation time is often seen in temporal lobe epilepsy (TLE) with hippocampal sclerosis. Water content directly affects the effective T2 in a voxel. Our aim was to evaluate the relation between T2 values and two molecules associated with brain water homeostasis aquaporin 4 (AQP4) and chondroitin sulfate proteoglycan (CSPG), as well as cellular populations in the hippocampal region of patients with TLE. Hippocampal T2 imaging and diffusion tensor imaging (DTI) were obtained from 42 drug-resistant patients with TLE and 20 healthy volunteers (radiologic controls, RCs). A similar protocol (exvivo) was applied to hippocampal sections from the same TLE cases and 14 autopsy control hippocampi (histologic and radiologic controls, HRCs), and each hippocampal subfield was evaluated. Hippocampal sections from TLE cases and HRC controls were submitted to immunohistochemistry for neurons (neuron nuclei [NeuN]), reactive astrocytes (glial fibrillary acidic protein [GFAP]), activated microglia (human leukocyte antigen-D-related [HLA-DR]), polarized AQP4, and CSPG. Patients with TLE had higher invivo and exvivo hippocampal T2 relaxation time. Hippocampi from epilepsy cases had lower neuron density, higher gliosis, decreased AQP4 polarization, and increased CSPG immunoreactive area. In vivo relaxation correlated with astrogliosis in the subiculum and extracellular CSPG in the hilus. Ex vivo T2 relaxation time correlated with astrogliosis in the hilus, CA4, and subiculum, and with microgliosis in CA1. The difference between invivo and exvivo relaxation ratio correlated with mean diffusivity and with the immunopositive area for CSPG in the hilus. Our data indicate that astrogliosis, microgliosis, and CSPG expression correlate with the increased T2 relaxation time seen in the hippocampi of patients with TLE.

T2 relaxometry improves detection of non-sclerotic epileptogenic hippocampus

ObjectThe use of T2 relaxometry was investigated to detect non-sclerotic epileptogenic abnormality of the hippocampus in presurgical evaluation of temporal lobe epilepsy (TLE). MethodsThis prospective study included 30 patients who underwent hippocampectomy as part of surgical treatment of refractory TLE. Ten patients had structural epileptogenic lesions in the extra-hippocampal temporal lobe. Twelve patients underwent intracranial electroencephalography (iEEG) study before surgery. Visual assessment of atrophy and increased T2 signal intensity, volumetry, and T2 relaxometry of hippocampus were performed pre-operatively using 3T magnetic resonance imaging, and compared with the neuropathological findings and iEEG findings. Magnetic resonance imaging of 30 age- and sex-matched healthy controls was used to establish normal values, which were defined as z score within 2. ResultsVisual assessment, volumetry, and T2 relaxometry detected hippocampal abnormalities on the surgical side in 16 (53%), 16 (53%), and 26 (87%) patients, respectively. Hippocampal volume loss was always associated with prolonged T2 relaxation time, and supported by histopathological diagnosis of HS in all cases except one. Hippocampal abnormality was detected only by T2 relaxometry in nine patients (30%). Pathological diagnosis of these cases included mild HS in one, microdysgenesis in one, and granule cell pathology in three. Four patients with normal hippocampal volume and T2 relaxation time had no HS or granule cell pathology. Prolonged T2 relaxation time was associated with medial temporal seizure onset in iEEG (p<0.05). ConclusionsT2 relaxometry improves the detection of non-sclerotic epileptogenic abnormality of the hippocampus.

Changes in Hippocampal Volume are Correlated with Cell Loss but Not with Seizure Frequency in Two Chronic Models of Temporal Lobe Epilepsy.

Kainic acid (KA) or pilocarpine (PILO) have been used in rats to model human temporal lobe epilepsy (TLE) but the distribution and severity of structural lesions between these two models may differ. Magnetic resonance imaging (MRI) studies have used quantitative measurements of hippocampal T2 (T2HP) relaxation time and volume, but simultaneous comparative results have not been reported yet. The aim of this study was to compare the MRI T2HP and volume with histological data and frequency of seizures in both models. KA- and PILO-treated rats were imaged with a 2 T MRI scanner. T2HP and volume values were correlated with the number of cells, mossy fiber sprouting, and spontaneous recurrent seizures (SRS) frequency over the 9 months following status epilepticus (SE). Compared to controls, KA-treated rats had unaltered T2HP, pronounced reduction in hippocampal volume and concomitant cell reduction in granule cell layer, CA1 and CA3 at 3 months post SE. In contrast, hippocampal volume was unchanged in PILO-treated animals despite detectable increased T2HP and cell loss in granule cell layer, CA1 and CA3. In the following 6 months, MRI hippocampal volume remained stable with increase of T2HP signal in the KA-treated group. The number of CA1 and CA3 cells was smaller than age-matched CTL group. In contrast, PILO group had MRI volumetric reduction accompanied by reduction in the number of CA1 and CA3 cells. In this group, T2HP signal was unaltered at 6 or 9 months after status. Reductions in the number of cells were not progressive in both models. Notably, the SRS frequency was higher in PILO than in the KA model. The volumetry data correlated well with tissue damage in the epileptic brain, suggesting that MRI may be useful for tracking longitudinal hippocampal changes, allowing the assessment of individual variability and disease progression. Our results indicate that the temporal changes in hippocampal morphology are distinct for both models of TLE and that these are not significantly correlated to the frequency of SRS.

Qualitative and Quantitative Hippocampal MRI Assessments in Intractable Epilepsy

Aims. To acquire normative data of hippocampal volumes and T2 relaxation times, to evaluate and compare qualitative and quantitative assessments in evaluating hippocampi in patients with different durations of intractable epilepsy, and to propose an imaging protocol based on performance of these techniques. Methods. MRI analysis was done in 50 nonepileptic controls and 30 patients with intractable epilepsy on 1.5T scanner. Visual assessment and hippocampal volumetry were done on oblique coronal IR/T2W and T1W MP-RAGE images, respectively. T2 relaxation times were measured using 16-echo Carr-Purcell-Meiboom-Gill sequence. Volumetric data was normalized for variation in head size between individuals. Patients were divided into temporal (n = 20) and extratemporal (n = 10) groups based on clinical and EEG localization. Results. In controls, right hippocampal volume was slightly more than the left with no effect of age or gender. In TLE patients, hippocampal volumetry provided maximum concordance with EEG. Visual assessment of unilateral pathology concurred well with measured quantitative values but poorly in cases with bilateral pathologies. There were no significant differences of mean values between extratemporal group and controls group. Quantitative techniques detected mild abnormalities, undetected on visual assessment. Conclusions. Quantitative techniques are more sensitive to diagnose bilateral and mild unilateral hippocampal abnormalities.

Prediction and prevention of schizophrenia: what has been achieved and where to go next?

In modern medicine, vigorous efforts are being made in the prediction and prevention of diseases. Mental disorders are suitable candidates for the application of this program. The currently known neurobiological and psychosocial risk indicators for schizophrenia do not have a predictive power sufficient for selective prevention in asymptomatic patients at risk. However, once predictive basic and later pre-psychotic high risk symptoms of psychosis develop into the five-year initial prodrome, the impending outbreak of the disease can be predicted with high accuracy. Research findings suggest a differential strategy of indicated prevention with cognitive behavioral therapy in early initial prodromal states and low dosage atypical antipsychotics in late initial prodromal states. The most important future tasks are the improvement of the predictive power by risk enrichment and stratification, as well as the confirmation of the existing and the development of new prevention strategies, with a stronger focus on the etiology of the disorder. In addition, the prediction and prevention approach would benefit from the inclusion of risk symptoms in the DSM-5 criteria.

Hippocampal pathology in individuals at ultra-high risk for psychosis: A multi-modal magnetic resonance study

Although the hippocampus is a key brain region in the pathophysiology of schizophrenia, it is unclear whether structural or biochemical abnormalities predate illness onset. In this study, we used magnetic resonance imaging and spectroscopy data acquired prior to both the onset of psychosis and treatment with antipsychotics to determine this. Sixty-six young people clinically at ultra high-risk of development of psychosis were recruited, 59 of whom did not later develop a psychotic disorder and 7 who had done so after at least 24months follow-up. These participants were compared with 29 healthy comparison subjects on multiple independent magnetic resonance measures: hippocampal volume, hippocampal T2 relaxation time, and medial temporal lobe metabolite concentrations (including N-acetylaspartate). We found similar reductions in left hippocampal volume in the at-risk group compared to comparison subjects regardless of later transition status; on the right this only reached significance for the at-risk group who did not transition to psychosis. T2 relaxation time in the left hippocampal head was significantly elevated in the later-psychotic group, and this elevation positively correlated with total positive symptoms in the UHR group as a whole. Medial temporal lobe metabolite concentrations did not differ. These findings suggest that there are subtle pathological changes in the hippocampus prior to the development of psychosis, but that they are limited to the left hippocampal head. However, standard measures of neuroanatomical disturbance do not appear to be predictive of later transition, and instead are likely to be non-specific and common in cases that later develop a non-psychotic disorder.

Short- and long-term limbic abnormalities after experimental febrile seizures

Experimental febrile seizures (FS) are known to promote hyperexcitability of the limbic system and increase the risk for eventual temporal lobe epilepsy (TLE). Early markers of accompanying microstructural and metabolic changes may be provided by in vivo serial MRI. FS were induced in 9-day old rats by hyperthermia. Quantitative multimodal MRI was applied 24 h and 8 weeks later, in rats with FS and age-matched controls, and comprised hippocampal volumetry and proton spectroscopy, and cerebral T2 relaxometry and diffusion tensor imaging (DTI). At 9 weeks histology was performed. Hippocampal T2 relaxation time elevations appeared to be transient. DTI abnormalities detected in the amygdala persisted up to 8 weeks. Hippocampal volumes were not affected. Histology showed increased fiber density and anisotropy in the hippocampus, and reduced neuronal surface area in the amygdala. Quantitative serial MRI is able to detect transient, and most importantly, long-term FS-induced changes that reflect microstructural alterations.

Imaging Depression in Epilepsy: Hints at the Biology of Despair

Major Depression in Temporal Lobe Epilepsy with Hippocampal Sclerosis: Clinical and Imaging Correlates. Briellmann RS, Hopwood MJ, Jackson GD. J Neurol Neurosurg Psychiatry 2007 Jan 26; [Epub ahead of print] PURPOSE: Refractory temporal lobe epilepsy (TLE) is often associated with hippocampal sclerosis (HS). Patients with Major Depression (MD) may also show structural abnormalities in the limbic system. Co-occurrence of TLE with HS and MD is not uncommon. We investigate clinical and morphological characteristics of TLE patients in relation to MD. METHODS: Thirty-four TLE patients with HS were assessed at a Comprehensive Epilepsy Program. All relevant clinical data were obtained, including the history of antecedent events to epilepsy. MD was diagnosed based on detailed psychiatric investigation. MRI was used to measure the volume and tissue signal (T2-relaxometry) of the hippocampus and amygdala. The imaging data were expressed as percentage of the values obtained in a series of 55 controls. RESULTS: A history of MD was present in 15 (44%) of the 34 patients. Patients with MD had a longer duration of their epilepsy ( p &lt; 0.05), and a lower frequency of antecedent events (13% with MD, 58% without MD, p &lt; 0.05). Both groups had a similar degree of ipsilateral HS (small hippocampal volume, increased hippocampal T2-relaxation time), and demonstrated bilateral amygdaloid atrophy. However, the contralateral amygdala showed lower signal in presence of MD (97 ± 9 msec; no MD: 103 ± 8 msec, ANCOVA, p &lt; 0.05). CONCLUSION: The integrity of the amygdala may influence mood disturbances in TLE patients with HS, as depression was associated with a relative preservation of the contralateral amygdala. In contrast, hippocampal abnormalities were not related to the presence of depression. Hippocampal 1H-MRSI Correlates with Severity of Depression Symptoms in Temporal Lobe Epilepsy. Gilliam FG, Maton BM, Martin RC, Sawrie SM, Faught RE, Hugg JW, Viikinsalo M, Kuzniecky RI. Neurology 2007;68(5):364–368. OBJECTIVE: To investigate the association of an indicator of hippocampal function with severity of depression symptoms in temporal lobe epilepsy. METHODS: We evaluated 31 patients with video/EEG-confirmed temporal lobe epilepsy using creatine/ N-acetylaspartate ratio maps derived from a previously validated 1H magnetic resonance spectroscopic imaging (1H-MRSI) technique at 4.1 T. We also assessed depression symptoms, epilepsy-related factors, and self-perceived social and vocational disability. We used conservative nonparametric bivariate procedures to determine the correlation of severity of depression symptoms with imaging and clinical variables. RESULTS: The extent of hippocampal 1H-MRSI abnormalities correlated with severity of depression (Spearman rho = 0.65, p value &lt; 0.001), but other clinical factors did not. CONCLUSION: The extent of hippocampal dysfunction is associated with depression symptoms in temporal lobe epilepsy and may be a more important factor than seizure frequency or degree of disability.

T2 Relaxometry of the Hippocampus at 3T

T2 mapping is useful for identifying and quantifying abnormalities of the hippocampus and amygdala. It is particularly useful in the presurgical evaluation of patients with temporal lobe epilepsy and for the identification of bilateral hippocampal sclerosis (HS). The purpose of this study was to implement and validate a dual-echo method for producing coronal T2 maps with complete coverage of the hippocampus and the rest of the brain on a 3T MR imaging scanner. T2 relaxation times were estimated on 10 occasions on 3 quality assessment Eurospin II (Diagnostic Sonar, Livingstone, Scotland) test objects with the use of conventional spin-echo (CSE), fast spin-echo, and fast recovery fast spin-echo (FRFSE) sequences on a 3T Excite MR imaging scanner (GE Healthcare, Milwaukee, Wis). Hippocampal T2 relaxation times were then measured in 15 healthy subjects and 20 subjects with clear-cut HS who were scanned at 1.5 T with a previously validated dual-echo CSE sequence and 3T with an FRFSE sequence. 3T FRFSE data were as reliable as CSE data at 1.5 T. Reliability of hippocampal T2 measures was good on healthy volunteers and subjects with HS. FRFSE images were suitable for qualitative radiologic reporting and with complete brain coverage, so no additional T2-weighted sequences were required. There was good correlation between the 3T hippocampal T2 measurements and values obtained with the previously validated technique at 1.5 T, with reliable identification of all of the subjects with HS. T2 mapping with an FRFSE 30/80 sequence may be readily applied at 3T and can produce reliable T2 values in vivo with contiguous 5-mm sections and in a much reduced scan time of 3 minutes 1 second compared with 10 minutes 30 seconds for the CSE sequence at 1.5 T.

Major depression in temporal lobe epilepsy with hippocampal sclerosis: clinical and imaging correlates

Purpose:Refractory temporal lobe epilepsy (TLE) is often associated with hippocampal sclerosis (HS). Patients with major depression (MD) may also show structural abnormalities in the limbic system. Co-occurrence of TLE with...

A Six-Year Follow-Up MRI Study of Complicated Early Childhood Convulsion

We have previously reported a greater than 50% prevalence of structural brain abnormalities in children within 2 weeks of first complicated early childhood convulsion, including significant hippocampal asymmetry unrelated to edema. In a 6-year follow-up study, 8 of the original 17 subjects were reimaged to determine any developments in hippocampal pathology. Three subjects manifested significantly greater asymmetry, and two exhibited a modest increase in asymmetry at follow-up compared with that present at initial magnetic resonance imaging. Two of the remaining three subjects manifested no change in the degree of hippocampal asymmetry that was already evident at initial scan, whereas in the final case, apparent resolution of previously identified (slight) hippocampal asymmetry had occurred. Elevated hippocampal T2 relaxation times did not consistently accord with smaller hippocampal volumes. These results suggest that complicated early childhood convulsion may be less benign than often supposed.

Cerebral Damage in Epilepsy: A Population‐based Longitudinal Quantitative MRI Study

Whether cerebral damage results from epileptic seizures remains a contentious issue. We report on the first longitudinal community-based quantitative magnetic resonance imaging (MRI) study to investigate the effect of seizures on the hippocampus, cerebellum, and neocortex. One hundred seventy-nine patients with epilepsy (66 temporal lobe epilepsy, 51 extratemporal partial epilepsy, and 62 generalized epilepsy) and 90 control subjects underwent two MRI brain scans 3.5 years apart. Automated and manual measurement techniques identified changes in global and regional brain volumes and hippocampal T2 relaxation times. Baseline hippocampal volumes were significantly reduced in patients with temporal lobe epilepsy and could be attributed to an antecedent neurologic insult. Rates of hippocampal, cerebral, and cerebellar atrophy were not syndrome specific and were similar in control and patient groups. Global and regional brain atrophy was determined primarily by age. A prior neurologic insult was associated with reduced hippocampal and cerebellar volumes and an increased rate of cerebellar atrophy. Significant atrophy of the hippocampus, neocortex, or cerebellum occurred in 17% of patients compared with 6.7% of control subjects. Patients with and without significant volume reduction were comparable in terms of seizure frequency, antiepileptic drug (AED) use, and epilepsy duration, with no identifiable risk factors for the development of atrophy. Overt structural cerebral damage is not an inevitable consequence of epileptic seizures. In general, brain volume reduction in epilepsy is the cumulative effect of an initial precipitating injury and age-related cerebral atrophy. Significant atrophy developed in individual patients, particularly those with temporal lobe and generalized epilepsy. Longer periods of observation may detect more subtle effects of seizures.

Hippocampal Abnormalities after Prolonged Febrile Convulsions

Hippocampal volume and T2 relaxation times were determined in an MRI study of 14 children with prolonged febrile convulsions (PFC) who were investigated, 1) within 5 days of a PFC, and 2) at follow-up 4-8 months after the acute study, at the Institute of Child Health, University College, and Great Ormond Street Hospital, London, UK.

Hippocampal abnormalities after prolonged febrile convulsion: a longitudinal MRI study.

Mesial temporal sclerosis (MTS) is the most common lesion in patients who require epilepsy surgery, and approximately 50% of patients with MTS have a history of prolonged febrile convulsion (PFC) in childhood. The latter led to the hypothesis that convulsive status epilepticus, including PFC, can cause MTS. Our recently published data on children investigated within 5 days of a PFC showed that children investigated by MRI within 48 h of a PFC had large hippocampal volumes and prolongation of T2 relaxation time. Patients investigated >48 h from a PFC had large hippocampal volumes and normal T2 relaxation time. These data are strongly suggestive of hippocampal oedema that is resolving within 5 days of a PFC, but do not exclude the possibility of a pre-existing hippocampal lesion. Fourteen children from the original study had follow-up investigations carried out 4-8 months after the acute investigations. Of the 14 patients, four have had further seizures. Two had short febrile convulsions, one had PFC and one had non-febrile seizures. There was a significant reduction in hippocampal volume and T2 relaxation time between the first and second investigations, and there is now no difference in hippocampal volume or T2 relaxation time in patients compared with a control population. Moreover, there is a significant increase in hippocampal volume asymmetry in patients at follow-up when compared with initial data. Five out of 14 patients had asymmetry outside the 95th percentile for control subjects and, of these, three had one hippocampal volume outside the lower 95% prediction limit for control subjects. A reduction in hippocampal volume or T2 relaxation time, into or below the normal range between the first and second scans, indicates that the earlier findings are temporary and are strongly suggestive of hippocampal oedema as the abnormality in the initial investigations. The change in hippocampal symmetry in the patient group is consistent with injury and neuronal loss associated with a PFC, especially in the three individuals who now have a single small hippocampus. However, as there is no T2 relaxation time abnormality, the hippocampi do not meet the criteria for MTS. There may be a lag period of several years between a PFC and the onset of epilepsy, and therefore some of these patients may be developing MTS. Alternatively, the asymmetry could represent return (post-acute oedema) to a pre-existing hippocampal abnormality similar to that identified in family members of patients with MTS and a history of PFC.

Memory Function Related to Hippocampal Imaging Findings.

The Relationship Between Quantitative T2 Relaxometry and Memory in Nonlesional Temporal Lobe Epilepsy Wendel JD, Trenerry MR, Xu YC, Sencakova D, Cascino GD, Britton JW, Lagerlund TD, Shin C, So EL, Sharbrough FW, Jack CR Epilepsia 2001;42:863–868 Purpose We investigated the relationship between preoperative quantitative magnetic resonance imaging (MRI) T2 relaxometry and volumetry of the hippocampi and pre- and postoperative verbal memory in temporal lobectomy patients who had nonlesional temporal lobe epilepsy. Methods Pre- and postoperative memory data based on the Logical Memory (LM) subtest of the Wechsler Memory Scale-Revised (WMS-R) and the 30-min delayed recall trial of the Rey Auditory Verbal Learning Test (AVLT) were obtained from 26 left and 15 right temporal lobectomy patients. Coronal MRI T2 maps were generated for these 41 temporal lobectomy patients as well as 61 control patients. Hippocampal T2 relaxation times and hippocampal volumes, converted to z scores using control group data, were correlated with neuropsychological performance in the patients. Results In left temporal lobe-onset patients, high T2 in the left hippocampal body predicted higher LM performance after surgery. Asymmetrically high T2 in the left hippocampal body (i.e., the right-minus-left difference), compared with the right hippocampal body, also predicted higher LM performance after surgery. In right temporal lobe-onset patients, high T2 in the left hippocampal body predicted relatively lower AVLT performance after surgery. Multiple regression analysis in left temporal-onset patients revealed that high T2 in the left hippocampal body together with higher preoperative LM performance predict higher postoperative LM performance. Conclusions Our findings suggest that elevated (i.e., abnormal) hippocampal T2 signal is associated with memory ability (or hippocampal functional capacity) independent of MRI-determined hippocampal atrophy. Therefore, our findings support the use of quantitative T2 relaxometry as an independent predictor of verbal memory outcome in both left and right TLE patients who are candidates for temporal lobectomy.

A magnetic resonance study of complicated early childhood convulsion

OBJECTIVESThe relation between complicated early childhood convulsion (ECC) and adult epilepsy is unclear, although a history of complicated ECC is obtainable in half of adults with epilepsy associated with hippocampal...

The relationship between quantitative T2 relaxometry and memory in nonlesional temporal lobe epilepsy.

We investigated the relationship between preoperative quantitative magnetic resonance imaging (MRI) T2 relaxometry and volumetry of the hippocampi and pre- and postoperative verbal memory in temporal lobectomy patients who had nonlesional temporal lobe epilepsy. Pre- and postoperative memory data based on the Logical Memory (LM) subtest of the Wechsler Memory Scale-Revised (WMS-R) and the 30-min delayed recall trial of the Rey Auditory Verbal Learning Test (AVLT) were obtained from 26 left and 15 right temporal lobectomy patients. Coronal MRI T2 maps were generated for these 41 temporal lobectomy patients as well as 61 control patients. Hippocampal T2 relaxation times and hippocampal volumes, converted to z scores using control group data, were correlated with neuropsychological performance in the patients. In left temporal lobe-onset patients, high T2 in the left hippocampal body predicted higher LM performance after surgery. Asymmetrically high T2 in the left hippocampal body (i.e., the right-minus-left difference), compared with the right hippocampal body, also predicted higher LM performance after surgery. In right temporal lobe-onset patients, high T2 in the left hippocampal body predicted relatively lower AVLT performance after surgery. Multiple regression analysis in left temporal-onset patients revealed that high T2 in the left hippocampal body together with higher preoperative LM performance predict higher postoperative LM performance. Our findings suggest that elevated (i.e., abnormal) hippocampal T2 signal is associated with memory ability (or hippocampal functional capacity) independent of MRI-determined hippocampal atrophy. Therefore, our findings support the use of quantitative T2 relaxometry as an independent predictor of verbal memory outcome in both left and right TLE patients who are candidates for temporal lobectomy.

Relationship between histopathological diagnosis of hippocampal sclerosis and pre-surgical measurement of hippocampal volume and T2 relaxation time in patients with intractable temporal lobe epilepsy

Relationship between histopathological diagnosis of hippocampal sclerosis and pre-surgical measurement of hippocampal volume and T2 relaxation time in patients with intractable temporal lobe epilepsy