Role of hippocampal volumetry in drug resistant epilepsy
DOI:
https://doi.org/10.18203/2320-6012.ijrms20193398Keywords:
Drug resistant epilepsy, Epilepsy, hippocampal volume, Manual hippocampal volumetryAbstract
Background: Hippocampus is a brain structure located deep in the temporal lobe. The structure is crucial for learning and memory and is a natural inhibitor of seizure activity in brain. In drug resistant epilepsy (DRE), there is shrinkage of the hippocampus leading to poor seizure control.
Methods: Patients meeting the diagnostic criteria for drug resistant epilepsy between the age group of 10-60 years were enrolled in the study. Epileptic non drug resistant controls and normal healthy individuals were taken from same cohort. Selected patients underwent MRI Brain and their hippocampal volumes were estimated manually. Coronal oblique sections, perpendicular to the long axis of hippocampus were taken and hippocampal volume (HV) were calculated using region of interest approach with manual delineation .
Results: There was increment in detecting hippocampal atrophy from 30% to 46.6% in DRE patients when manual hippocampal atrophy was used in addition to visual assessment. The mean right and left hippocampal volumes in drug resistant epilepsy cases were found to be 2.17+0.57 cc and 1.52+0.54 cc respectively. Left HV was found to be statistically significantly smaller than right side (p value < 0.05). DRE patients had smaller mean bilateral HV than healthy controls, the difference being 33%. The left HV loss was almost double the right HV loss among DRE cases. The hippocampal volumes were reduced in DRE patients compared to epileptic non-resistant patients; however the difference was found to be less than that of normal healthy controls.
Conclusion: Manual hippocampal volumetry detected more patients with hippocampal atrophy in our study compared to visual assessment. Manual hippocampal volumetry should be routinely done in patients with Drug resistant epilepsy.
References
Anand KS, Dhikav V. Hippocampus in health and disease: An overview. Ann Indian Acad Neurol. 2017 Jan-Mar;20(1):29-35.
Dhikav V, Duraisamy S, Anand KS, Garga UC. Hippocampal volumes among older Indian adults: Comparison with Alzheimer's disease and mild cognitive impairment. Ann Indian Acad Neurol. 2016 Apr-Jun;19(2):195-200.
Avoli M. The epileptic hippocampus revisited: back to the future. Epilepsy Curr. 2007Jul;7(4):116-8
Bonilha L, Keller SS. Quantitative MRI in refractory temporal lobe epilepsy: relationship with surgical outcomes. Quant Imaging Med Surg. 2015;5(2):204-24.
Farid N, Girard HM, Kemmotsu N, Smith ME, Magda SW, Lim WY, et al. Temporal lobe epilepsy: quantitative MR volumetry in detection of hippocampal atrophy. Radiol. 2012 Aug;264(2):542-50.
Singh P, Kaur R, Saggar K, Singh G, Kaur A. Qualitative and quantitative hippocampal MRI assessments in intractable epilepsy. Biomed Res Int. 2013:480-524.
Tripathi M, Padhy UP, Vibha D, Bhatia R, Padma Srivastava MV, Singh MB, et al. Predictors of refractory epilepsy in north India: a case-control study. Seizure. 2011 Dec 1;20(10):779-83.
Mohandas AN, Bharath RD, Prathyusha PV, Gupta AK. Hippocampal volumetry: Normative data in the Indian population. Ann Indian Acad Neurol. 2014 Jul;17(3):267.
Kwan P, Arzimanoglou A, Berg AT, Brodie MJ ,Hauser WA, Mathern G, et al. Definition of drug resistant epilepsy: Consensus proposal by the ad hoc Task Force of the ILAE Commission on Therapeutic Strategies. Epilepsia. 2010 Jun;51(6):1069-77.
Dhikav V, Duraiswamy S, Anand KS. Correlation between hippocampal volumes and medial temporal lobe atrophy in patients with Alzheimer's disease. Ann Indian Acad Neurol. 2017 Jan;20(1):29-35.
Coan AC, Kubota B, Bergo FPG, Campos BM, Cendes F. 3T MRI quantification of hippocampal volume and signal in mesial temporal lobe epilepsy improves detection of hippocampal sclerosis. AJNR Am J Neuroradiol. 2014 Jan 1;35(1):77-83.
Fuerst D, Shah J, Shah A, Watson C. Hippocampal sclerosis is a progressive disorder: a longitudinal volumetric MRI study. Ann Neurol. 2003 Mar;53(3):413-6.
