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October2013 Vol.50 Issue:      4 Table of Contents
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Temporal lobe Epilepsy: Correlation between Electroencephalography and Magnetic Resonance Spectroscopy

Sabah M. Lotfy1, Heba A. Selim1, Hanan Salah1, Seham F. Abd Elhamed2,

Ghada Abdulmoneem3, Enass M. Khattab3

Departments of Neurology1, Pediatrics2, Radiodiagnosis3, Zagazig University; Egypt



ABSTRACT

Background: Patients with temporal lobe complex partial seizures constitutes the majority of patients referred for surgical consideration. Objective: Our study was designed to evaluate the ability of magnetic resonance spectroscopy in detecting the side of the epileptic focus in patients with temporal lobe epilepsy in relation to electroencephalography. Methods: 29 patients with non-lesional temporal lobe epilepsy and 14 healthy volunteers as a control group were included in our study. All patients were subjected to clinical examination, interictal electroencephalography and magnetic resonance imaging. Proton magnetic resonance spectroscopic examination was performed to the patients and the controls. Results: According to the findings of electroencephalography, our patients were classified to three groups: Group 1 consisted of 16 patients with unitemporal (lateralized) epileptic focus, group 2 consisted of 8 patients with bitemporal (non-lateralized) epileptic focus and group 3 consisted of 5 patients with normal electroencephalography. Magnetic resonance spectroscopy could lateralize the epileptic focus in 15 patients in group 1, six patients in group2 and three patients in group 3 with overall lateralization of (82.75%), while electroencephalography was able to lateralize the focus in (55.17%) of patients and magnetic resonance imaging detected lateralization of mesial temporal sclerosis in 58.6% of patients. Conclusion: Magnetic resonance spectroscopy is a promising tool in evaluating patients with epilepsy and offers increased sensitivity to detect temporal pathology that is not obvious on structural MRI imaging. [Egypt J Neurol Psychiat Neurosurg.  2013; 50(4): 441-448] 

Key Words: Temporal lobe epilepsy, Electroencephalography, Magnetic resonance spectroscopy.

Correspondence to Sabah M. Lotfy, Department of Neurology, Zagazig University, EgyptTel.: +201224819019. email: dr.sabahlotfy67@yahoo.com





INTRODUCTION

 

Epilepsy is one of the most common neurological disorders after stroke and affects at least 50 million people world wide.1 Approximately two-thirds of patients with epilepsy have partial epilepsy, with the majority originating in the temporal lobes. Epilepsy of temporal lobe origin is characterized by considerable heterogenicity in clinical history, ictal symptoms, electroencephalographic characteristics and neuroimaging finding.2

Temporal lobe epilepsy (TLE) with seizure onset from the mesial temporal lobe structure is recognized as a syndrome of mesial temporal lobe epilepsy (MTLE) and it comprises the majority of cases of epilepsy refractory to pharmacotherapy.3

Patients with temporal lobe complex partial seizures constitutes the majority of patients referred for surgical consideration. Surgical removal of the focus eliminates or greatly reduces seizures in about 90% of patients with TLE who have concordant hippocampal atrophy.4

In temporal lobe epilepsy the interictal scalp electroencephalogrpahy (EEG) may show the following: No abnormality, slight or marked asymmetry of the background activity, temporal spikes; sharp waves and/or slow waves, unilateral or bilateral, synchronus or asynochrous, these findings are not always confined to the temporal  region.5

On magnetic resonance images (MRI), mesial temporal sclerosis displays hippocampal atrophy, prolonged T2, and structural distortion. These changes may be assessed both qualitatively or by means of hippocampal volumetry and T2 relaxometry, which increase MR imaging sensitivity, even after quantitative studies, about 20% of patients with TLE have negative structural MR images. Patients with negative structural MR images have poorer seizure control after hippocampectomy.6 Hydrogen spectroscopic imaging depicts the anatomic distribution of metabolite signals from N-acetylaspartate (NAA), creatine (Cr) and choline (Cho)-containing compounds, NAA is of major interest due to its predominantly neuronal distribution, reduction of NAA signal is usually interpreted as loss or dysfunction of neurons.7 Previous studies have shown that interictal NAA is reduced in the ipsilateral mesial temporal lobe, assisting in the lateralization of TLE even in cases with negative structural MR images.8 Proton magnetic resonance spectroscopy (1HMRS) has been proposed as a method for the presurgical evaluation of patients with medically intractable temporal lobe epilepsy.9,10

 

Aim of Work

We aimed to assess the ability of magnetic resonance spectroscopy (MRS) in detecting the lateralization side in patients with TLE in correlation with EEG and MRI findings.

 

PATIENTS AND METHODS

 

The current study was carried out on 29 patients (17 females and 12 males) and their age was ranged from 10 to 45 years (clinically and by EEG diagnosed as having temporal lobe epilepsy) who were attended the Neurology and Pediatric, clinics, Zagazig University Hospitals from July 2010 to April 2011 for either diagnosis or follow up of their illness.

The diagnosis of TLE was based on clinical history and seizures description according to the International League Against Epilepsy (ILAE) 19895 as it defined TLE as a localization related epilepsy with typical clinical and EEG characteristic and it includes, simple partial, complex partial, secondary generalized or a combination of both.

Patients were excluded if the imaging study (by MRI) revealed any focal abnormalities other than mesial temporal sclerosis (MTS).

Then we divided our patients according to EEG finding into 3 groups; group 1 consisted of 16 TLE patients with EEG finding lateralized to one temporal lobe (unitemporal) and their mean age was 27.9±9.3 years, group 2 which consisted of 8 patients with TLE without lateralization of the focus by EEG (bitemporal) with a mean age of 29.5±8.3 years, and group 3 which included 5 TLE patients clinically diagnosed as TLE with normal EEG and their mean age was 29.0±11.9 years.

14 healthy volunteers (9 females and 5 males) with a mean age of 28 years ± 8.5) were included in this study as a control group.

Informed concent was taken from the patients and the controls or their parents. All the patients and the controls underwent clinical neurological examination and MRS examination. Video scalp EEG and MRI brain were performed to the patients.

Electroencephalography (EEG) was done to all patients using the GALILEO BE_LIGHT system. This system has a standard number of 28 channels.

During this procedure, the EEG is recorded for a prolonged period, accompanied by continuous closed-circuit video observation. The digitalized EEG and recorded behavior are displayed simultaneously, allowing point-to-point correlations of recorded events and any accompanying electrographic changes.

During video-EEG monitoring, the patient wears an EEG transmitter connected to coaxial cable. Wall-mounted video cameras provide continuous behavioral observation. Both EEG and video signals are transmitted to the EEG recording device, The EEG signal and video are displayed simultaneously for on-line observation, and both are recorded on hard drive or DVDs.

The entire duration of the EEG evaluation was analyzed, a sharp wave was considered epileptiform when it had a sharp morphology, duration of < 200 ms, and was clearly distinct from EEG background. Unitemporal interictal discharges (IEDs) required a minimum of 80 % of lateralization. In patients with <80% of interictal EEG onset lateralized to one side were considered bitemporal IEDs.7

All patients underwent conventional MRI study at 1.5-Tesla MR units (Achiva; Philips Medical Systems, Cleveland, Ohio). Conventional axial and sagittal T1-weighted images (TR 500ms/TE 15ms/slice thickness 5 mm/ slice gap 1.5 nun), axial FLAIR (TR 6000ms/TE 120ms/ TI 2000ms thickness 5mm/slice gab 1mm). Thin coronal sections were obtained for temporal lobes, included T2WI (TR 3000ms/TE 80ms) and FLAIR images (TR 6000ms/TE120ms with TI 2000).

Single-voxel proton MR spectroscopy was carried out immediately after MR imaging with an 8 cm3 voxel (2x2x2cm) positioned over the mesial temporal lobe at thin coronal T2-weighted images or FLAIR, including a part of the hippocampus. A point-resolved spectroscopy (PRESS) with chemical-shift selective (CHESS) water suppressed spectroscopic images were acquired. The acquisition parameters used were  TR of 1000, TE of 35 ms, a field of view of 240 × 240 mm, and 32 × 32 phase encodes with a slice thickness of 1 cm. An automatic and operator-nondependent processing scheme was achieved to analyze the spectra recorded for our study. The signal intensity of various metabolite peaks was evaluated in every voxel, using integrals of each peak as a measure of its intensity. Three resonances of the important metabolites were identified; NAA at 2.02 ppm, Cr at 3.02 ppm, and Cho at 3.22 ppm. The relative ratios of NAA to Cr were estimated for both temporal lobes of each patient and control group.

 

Statistics Analysis

Data were expressed as numbers, percentage and mean ± standard deviation. P value <0.05 was considered significant, P value <0.001 was considered highly significant and P value >0.05 was considered non significant. To test the significance of the relation between IEDs and NAA/Cr ratio in the temporal region, Spearmans rank correlation was used.

RESULTS

 

Our study included 29 patients; 12 males and 17 females, 16 patients in the first group with unitemporal (lateralized) interitcal discharges and their mean age was 27.9±9.3 years and 8 patients in the second group with bitemporal (nonlateralized) IEDs with a mean age of 29.5±8.3 years and 5 patients in the third group with normal EEG and their mean age was 29.0±11.9 and also our study included 14 health volunteers as a control group they were 9 females and 5 males with a mean age of 28 ±8.5 years.

The demographic characteristic of the 3 groups of patients were illustrated in Table (1). There was no significant difference between the 3 groups as regards age, sex, duration of epilepsy or previous insult.

When we compared the metabolic ratio (NAA/Cr ratio) between the 3 groups of patients and the control group we found that there was a significant difference between the patients and the controls groups with a decreased level in the patients groups (Table 2).

In addition, there was a significant correlation between NAA/Cr ratio and the duration of epilepsy (Table 3).

When we study the ability of 1HMRS and MRI to localize the side of epileptic focus in comparison with EEG, we found that, in the first group with unitemporal localized IEDs in EEG (16 patients) the epileptic focus was unilateral in 12 patients and bilateral with left or right predominance in 4 patients, in this group 1HMRS abnormalities (decreased NAA/Cr ratio) were lateralized in 15 out of 16 patients (93.75%) and it was unilateral in 13 patients and bilateral with left or right predominance in 2 patients and MRS was normal in 1 patient, while in this group MRI detected abnormalities with mesial temporal sclerosis (MTS) lateralized to one side in 9 (56.75%) patients out of 16 patients and the remaining 7 patients; 3 patients had nonlateralized lesions and 4 patients had normal MRI. The second group included 8 patients with bitemporal nonlateralized IEDs on EEG, we found that 1HMRS showed lateralization in 6 patients (75%) and it was unilateral in 4 patients and bilateral with one side predominance in 2 patients (Figure 1) and the another 2 patients (25%) showed bitemporal metabolic abnormalities with no lateralization, while MRI showed abnormalities in 6 patients (75%) and it was normal in 2 patients (25%).

The third group of patients with TLE included 5 patients with normal EEG, we found that 1HMRS detected metabolic abnormalities in 4 patients (80%); 3 patients (60%) with unitemporal lateralized lesions and it was unilateral in 2 patients and bilateral in one patient (Figure 2) and one patient (20%) with bitemporal metabolic abnormalities without lateralization, and one patient (20%) had normal MRS while MRI showed abnormalities lateralized to one side in 2 patients in this group (40%) and one patient (20%) had nonlateralized lesion and one patient (20%) had normal MRI (Table 4). So from this table we concluded this results as follow: from overall 29 patients with TLE; EEG detected lateralization of IEDs in 16 patients (55.17%) while 1HMRS detected metabolic abnormalities lateralized to one side in 24 patients (82.75%) and MRI detected lateralized abnormalities in 17 patients (58.6%).

When we study the correlation between IEDs on EEG and metabolic changes by 1HMRS we found that there was a significant negative correlation between IEDs and NAA/Cr ratio (Table 5).


 

 

Table 1. Demographic data of the patients.

 

 

Group 1

N=16

Group 2

N=8

Group 3

N=5

P-value

Age (years)

27.9±9.3

29.5±8.3

29.0±11.9

0.88

Gender (M/F)

6/10

4/4

2/3

0.84

Duration of epilepsy (years)

12.5±10.3

14.5±9.3

13.9±11

0.8

Previous insult :

               Febrile convulsions

               CNS infection

 

4

2

 

2

1

 

1

0

 

0.77

0.56

 

Table 2. Metabolic ratio by MRS in the 3 groups of patients and control group.

 

 

Group 1

N = 16

Group 2

N = 8

Group 3

N = 5

Control

P-value

NAA/Cr (Lt)

1.68±0.4

1.64±0.6

1.63±0.5

1.90±0.26

0.04*

NAA/Cr (Rt)

1.58±0.4

1.59±0.5

1.57±0.48

1.99±0.31

0.021*

NAA/Cr N-acetyl aspartate/creatin ratio, Lt Left, Rt Right,

* Significant at p<0.05

 

Table 3. Correlation between duration of epilepsy and NAA/Cr ratio.

 

 

r

P

Duration of epilepsy (years) Vs NAA/Cr ratio

-0.56

<0.001**

NAA/Cr ratio: N-acetyl-aspartate/creatine

*Significant at p<0.01

 

 

 

 

Figure 1. A patient with temporal lobe epilepsy; EEG showed bitemporal interictal discharges without lateralization (A), both mesial temporal lobes showed abnormal high signal with atrophic changes at MRI (B), while at MRS showed abnormal decrease of NAA/Cr ratio at both temporal lobes more evident at right side (C), denoted right side lateralization, Left side NAA/Cr=1.5 (D). Right side NAA/Cr ratio = 1.1

 

A

Figure 2. A patient with temporal lobe epilepsy: EEG (A) and MRI (B) were normal, while MRS showed a decreased ratio of NAA/Cr at left side (C) in correlation with right side (D).  Right temporal NAA/Cr ratio was 1.77 and at left side ratio was 1.42.

 

Table 4. Comparison between EEG, 1HMRS and MRI for lateralization of the lesions.

 

EEG lateralization

n. of patients with lateralized lesions

1HMRS lateralization

n. of patients

MRI lateralization

n. of patients

Lateralized lesions

non lateralized lesions

normal MRS

Lateralized MTS lesions

non lateralized MTS lesions

normal MRI

Group 1 (lateralized) N = 16

15 (93.75%)

-

1 (6.25%)

9 (56.25%)

3 (18.75%)

4 (25%)

                    - Unilateral N = 12

Unilateral n= 13

 

 

 

 

 

                    - Bilateral N = 4

Bilateral n = 2

 

 

 

 

 

Group 2 (Non lateralized) N = 8

6 (75%)

2 (25%)

 

6 (75%)

-

2 (25%)

 

Unilateral n = 4

 

 

 

 

 

 

Bilateral n = 2

 

 

 

 

 

Group 3 (Normal EEG) N = 5

3 (60%)

1 (20%)

1 (20%)

2 (40%)

1 (20%)

2 (40%)

 

Unilateral n = 2

 

 

 

 

 

 

Bilateral n = 1

 

 

 

 

 

Total lateralization

 

 

16 (55.17%)

24 (82.75%)

17 (58.6%)

1HMRS Magnetic resonance spectroscopy, MTS Mesial temporal sclerosis, MRI Magnetic resonance imaging, n Number

Table 5. Correlation between 1HMRS metabolities and interictal epileptiform discharges.

 

 

r

P-value

Lt IEDs vs Lt NAA/Cr

-0.19

>0.05

Rt IEDs vs Rt NAA/Cr

-0.28

>0.05

All IEDs vs all NAA/Cr

-0.41

<0.05*

Lt IEDs Left interictal discharges, Rt IEDs Right interictal discharges, Lt NAA/Cr Left N-acetyl-aspartate/creatine, Rt NAA/Cr Right N-acetyl-aspartate/creatine,

*Significant at p<0.05

 


DISCUSSION

 

In the management of temporal lobe epilepsy, exact lateralization of seizure focus with a noninvasive study is crucial, because surgical resection of the epileptogenic lesion results in good outcome and a failure to lateralize the focus with noninvasive examination may lead to an invasive study or to additional surgery for placement of intracranial electrodes, which may have potential risks.11 However, many sources of temporal lobe epilepsy, including hippocampal sclerosis and developmental anomalies, may not be recognized, even by a variety of MR imaging techniques, including MR volumetry and measurement of T2 relaxation time.3  Preliminary reports on proton MRS have noted that it is a promising neuroimaging modality and most MRS studies in patients with temporal lobe epilepsy have shown a decrease in NAA, and NAA/Cr ratio.12 and this result was in agreement with our results as we found that NAA/Cr ratio decreased significantly in patients with TLE than in controls.

               Hammen and colleagues13 reported that the role of NAA is not established in detail. First reports attributed NAA reduction to irreversible neuronal tissue degeneration and cell loss, but in later studies, alteration of NAA were also associated with neuronal dysfunction reflecting a  reversible, dynamic state not principally characterized by tissue damage. Later studies focusing on neuronal dysfunction rather than cell death showed that NAA reduction is mainly based on mitochondrial pathway.

               We found that 1HMRS detected side of lateralization in 82.75% of patients while MRI detected abnormalities in (58.6%) and EEG detected lateralization in (55.17%) of patients. The results of the EEG (its ability in detecting the epileptic focus) was in agreement with Ebnor and Hopp14 as they reported that bitemporal spikes or sharp waves, maximal on the side of seizure origin, occur in 25% to 50% of patients with TLE. However, in Foldvary and colleagues15 study, they found that epileptic discharges are absent on serial recordings in 10% of patients with TLE. On the other hand, Blume16 suggested that the lack of temporal lobe epileptiform activity of TLE in about three routine EEGs needs reassessment of the diagnosis.

               As regarding the relation between 1HMRS and EEG, we found that there was a significant negative correlation between IEDs and NAA/Cr ratio and these results were in agreement with most of the previous studies as; Garcia and colleagues17 studied 16 patients with temporal lobe epilepsy by EEG and 1HMRS and they found that decreasing NAA correlated with increased spike frequency, and Sarles and colleagues18 studied 14 patients with frontal and temporal lobe epilepsy and they found that there was an overall trend in which spike frequency and NAA/Cr ratio were correlated inversely, although the results did not reach statistical significance, the trend was obvious.

               Also, Maton and colleagues19 in their study on 31 patients with TLE found that lateralized 1HMRS based hipocompal abnormalities were recorded in 95% of the patients with unilateral interictal epileptiform abnormalities and they found that bilateral metabolic 1H MRS-based abnormalities were recorded 3 times more often than was bitemporal EEG spiking, and  Hammen and colleagues13 studied 14 patients with TLE and they found a significant negative correlation between NAA values and degree of IEDs in intensive video EEG recording and also there were a significant negative correlation between duration of seizures and NAA/Cr ratio.

               While Park and colleagues20 in their study of 34 patient with mesial TLE found that reduced NAA/Cr ratio were correlated to IEDs contralateral but not ipsilateral to the EEG focus. They interpreted these results as a triggering pathomechanism located contralateral to the underlying EEG focus propably generating independent contralateral IEDs.

               In our study MRI detected changes in 17 (58.6%) out of 29 patients and 12 patients had normal MRI. Out of these 12 patients, MRS showed changes in 10 patients. This results were in agreement with Connelley and colleagues21 in their study of 25 patients as they found that 19 patients (76%) were believed to have hipocampal sclerosis. In addition, Connelly and colleagues22 in a different study found that MRS could detect metabolic abnormalities in patients with normal MRI and they concluded that MRS clearly provides an added value to MRI and enhance the sensitivity of global MR examination.

 

 

Conclusion

               MRS is a noninvasive neuroradiology technique. It is a promising tool in evaluating patients with epilepsy and offers increased sensitivity to detect mesial temporal pathology that is not obvious on structural MRI imaging. So, EEG and clinical data, in conjunction with magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) results, predict the localization of the epileptogenic zone in patients with TLE, and may reduce the need for intracranial EEG in patients with less well lateralized TLE.

 

Recommendation

In future studies, the use of scanners with higher field strength will be necessary to attribute spectral metabolite alterations to the degree of epileptic activity more confidently.

 

[Disclosure: Authors report no conflict of interest]

 

REFERENCES

 

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2.        Shorvon SD, Definitions and classifications of epilepsy in: Shorvoin SD, editor. Handbook of epilepsy treatment. Oxford: Blackwell Science; 2000. p. 1-15.

3.        Burgerman RS, Sperling MR, French JA, Saykin AJ, Michael R, Jacqualine A, et al. Comparison of mesial versus neocortical onset temporal lobe seizures: neurodiagnostic findings and surgical outcome. Epilepsia. 1995; 36:662-70.

4.        Willmann O, Wennberg R, May T, Woermann FG, Pohlmann-Eden B. The role of 1H Magnetic resonance spectroscopy in pre-operative evaluation for epilepsy surgery. A meta-analysis. Epilepsy Res. 2006; 71(2-3):149-58.

5.        Commission on Classification and Terminology of the International League Against Epilepsy (ILAE). Proposal for revised classification of epilepsies and epileptic syndrome. Epilepsia. 1989; 30:389-99.

6.        Van Paesschen W, Connelly A, Johnson CL, Duncan JS. The amygdala and intractable temporal lobe epilepsy: a quantitative magnetic resonance imaging study. Neurology. 1996, 47:1021-31.

7.        Ende GR, Laxer KD, Knowlton RC, Matson GB, Schuff W, Fein G, et al. Temporal lobe epilepsy: bilateral hippocampal metabolite changes revealed at proton MR spectroscopic imaging. Radiology. 1997; 202:809-17.

8.        Cendes F, Caramanos Z, Andermann F, Dubeau F, Arnold DL. Proton magnetic resonance spectroscopy imaging and magnetic resonance imaging volumetry in the lateralization of temporal lobe epilepsy: a series of 100 patients. Ann Neurol. 2004; 42:737-46.

9.        Ng TC, Comair YG, Xue M, So A, Majors A, Kolen H, et al. Temporal lobe epilepsy: presurgical localization with proton chemical shift imaging. Radiology. 1994; 193:465-72.

10.     Capizzano AA, Vermathen P, Laxer KD, Ende GR, Norman D, Rowley H. Temporal lobe epilepsy: qualitative reading of 1H MR spectroscopic images for presurgical evaluation. Radiology. 2001; 218:144-51.

11.     Awad IA, Rosenfeld J, Ahl J, Hahn JF, Lüders H. Intractable epilepsy and structural lesions of the brain: mapping, resection strategies, and seizure outcome. Epilepsia. 1991; 32:179-86.

12.     Park SW, Chang KH, Kim HD, Song IC, Lee DS. Lateralizing ability of single-voxel proton MRS in hippocampal sclerosis: Comparison with MR imaging and positron emission tomography AJNR. Am J Neuroradiol 2001; 22:625-31.

13.     Hammen T, Schwaz Z, Doelken M, Kerling F, Engelborn T, Standlbauer A, et al. 1H-MRS spectroscopy indicates severity markers in temporal lobe epilepsy: Correlation between metabolic alterations, seizures, and epileptic discharges in EEG. Epilepsia. 2002; 48(2):263-9.

14.     Ebnor A, Hoppe M. Non-invasive electroencephalogrpahy and mesial temporal sclerosis. J Clin Neurophysiol. 1995; 12:23-31.

15.     Foldvary N, Klem G, Birgaman W, Najm I. The localization value of ictal EEG in focal epilepsy. Neurology. 2001; 57(11):2022-8.

16.     Blume WT. Diagnosis and management of epilepsy. CMAJ. 2003; 168(4):441-8.

17.     Garcia PA, Laxer KD, Van Der Grand J, Hugg JW, Matson GV, Weiner MW. Correlation of seizure frequency with N-acetyle aspartate levels determined by magnetic resonance spectroscopic imaging. Magn Reson Imaging. 1997; 15:475-8.

18.     Serles N, Caramanos Z, Arnoid DL, Gotman J, Lee R. Relation of interictal spike frequency to 1H-MRS-measured NAA/Cr. Epilepsia. 1999; 40:1821-7.

19.     Maton B, Gilliam F, Sawrie S, Faught E, Hugg J, Kuzniecky R. Correlation of scalp EEG and 1HMRS metabolic abnormalities in temporal lobe epilepsy. Epilepsia. 2001; 42(3):417-22.

20.     Park SA, Kim GS, Lee SK, Lim SR, Heo K, Chang JW. Interictal epileptiform discharges relate to 1H-MRS detected metabolic abnormalities in mesial temporal lobe epilepsy. Epilepsia. 2002; 43:1385-9.

21.     Connelly A, Jackson GD, Duncan JS, King MD, Gadian DG. Magnetic resonance spectroscopy in temporal lobe epilepsy. Neurology. 1994; 44:141-7.

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الملخص العربى

 

صرع الفص الصدغى: العلاقة بين رسم المخ الكهربائى والرنين المغناطيسى الطيفى

 

          إن الرنين المغناطيسى الطيفى هو وسيلة هامة لتقييم المرضى المصابون بمرض صرع الفص الصدغى الغير مستجيب للعلاج الدوائى وذلك قبل إجراء الجراحة لهم لاستئصال البؤرة الصرعية. والهدف من هذا البحث هو تقييم قدرة الرنين المغناطيسى الطيفى على تحديد جهة البؤرة الصرعية فى مرضى صرع الفص الصدغى.

          ولقد أجريت هذه الدراسة على 29 مريضاً مصابون بمرض صرع الفص الصدغى و14 شخصاً من الأصحاء كمجموعة ضابطة.

ولقد تم إجراء الآتى للمرضى:

- الفحص الاكلينيكى للجهاز العصبى.

- رسام المخ الكهربائى بالفيديو (بين النوبات الصرعية).

- الرنين المغناطيسى الطيفى للمخ.

ولقد تلخصت النتاائج فيما يلى:

          حسب نتائج الفحص برسام المخ الكهربائى بالفيديو فقد تم تقسيم المرضى إلى ثلاث مجموعات:

المجموعة الأولى: شملت 16 مريضا توجد بهم البؤرة الصرعية فى ناحية واحدة بالفص الصدغى سواء الأيمن أو الأيسر.

المجموعة الثانية: تكونت من 8 مرضى ووجدت بهم البؤرة الصرعية غير محددة الاتجاه أى توجد بالناحيتين اليمنى واليسرى.

المجموعة الثالثة: وشملت 5 مرضى وكان رسم المخ بهؤلاء المرضى سليم ولا توجد بؤرة صرعية.

          وعند مقارنة قدرة الرنيين المغناطيسى الطيفى فى تحديد ناحية البؤرة الصرعية بالفص الصدغى فقد وجد أن الرنين المغناطيسى الطيفى استطاع تحديد اتجاه البؤرة الصرعية فى 15 مريضا من المجموعة الأولى وستة مرضى بالمجموعة الثانية وثلاثة مرضى بالمجموعة الثالثة بنسبة تحديد بلغت 82.75% بينما كان رسم المخ الكهربائى قادراً على تحديد الاتجاه فى 55.17% من المرضى.

          ونستخلص من هذه الدراسة أن الرنين المغناطيسى الطيفى بالاضافة إلى رسم المخ الكهربائى وأيضا الرنين المغناطيسى للمخ هم طرق مهمة لتقييم مرضى صرع الفص الصدغى.

 



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