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Updated: Jan 9, 2026
High-resolution In Vivo Manual Segmentation Protocol for Human Hippocampal Subfields Using 3T Magnetic Resonance Imaging
Published on: November 10, 2015
Can Qualitative Subfield Analysis on High-Resolution MRI Predict Histopathologic Subtypes of Hippocampal Sclerosis?
Smily Sharma1, Aditya Ajith1, Rajalakshmi Poyuran2
1From the Department of Imaging Sciences and Interventional Radiology (S.S., A.A., C.K., B.T.), Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala, India.
Background And Purpose:
The International League Against Epilepsy classifies hippocampal sclerosis (HS) on the basis of the degree of neuronal loss affecting hippocampal subfields. Due to the differences in clinical presentation and postoperative outcomes, preoperative prediction of HS subtypes by MRI can aid in surgical decision-making. The current study aims to evaluate the utility of preoperative high-resolution MRI in this prediction.
Materials And Methods:
With institutional ethics committee approval, we conducted a retrospective observational study in a single tertiary referral center. Consecutive histopathology-proved cases of unilateral mesial temporal sclerosis from January 2018 to June 2023 were included if the patients also had a preoperative MRI study on a 3T scanner performed with a high-resolution epilepsy protocol. Two neuroradiologists, blinded to the histopathologic results, independently performed MRI grading by assessing volume loss in the hippocampal subfields on a high-resolution 2D coronal T2-weighted sequence. The discrepancies were resolved by a senior neuroradiologist. An agreement was sought between the MRI grading and the histopathologic grading of HS.
Results:
A total of 106 patients (57 males) were included with a mean age of 23.8 years. Type 1 HS was the most common subtype on both MRI (n = 71) and histopathology (n = 89). MRI detected no HS/gliosis only (GO) subtype of HS with 72.7% (95% CI, 43.4%-90.3%) sensitivity and 97.9% (95% CI, 92.7%-99.4%) specificity, and type 1 HS with 75.3% (95% CI, 65.4%-83.1%) sensitivity and 76.5% (95% CI, 52.7%-90.4%) specificity. Despite good interobserver agreement (Cohen κ, 0.770; P < .01), MRI showed only a fair agreement with histopathology (Cohen κ, 0.328; P < .01) in subclassifying HS. For individual HS subtypes, MRI showed good agreement in predicting the GO subtype (Cohen κ, 0.736; P <.01) and fair agreement (Cohen κ, 0.362; P < .01) in predicting HS type 1.
Conclusions:
Hippocampal subfield analysis is feasible with high-resolution 3T MRI, with good interobserver agreement. MRI grading based on a qualitative assessment of volume loss in hippocampal subfields can predict the GO subtype with good agreement compared with histopathology. However, differentiation of HS types 1, 2, and 3 subtypes from each other may not be feasible preoperatively with the current clinical 3T MRI protocols.
