1
|
Kerr WT, McFarlane KN. Machine Learning and Artificial Intelligence Applications to Epilepsy: a Review for the Practicing Epileptologist. Curr Neurol Neurosci Rep 2023; 23:869-879. [PMID: 38060133 DOI: 10.1007/s11910-023-01318-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2023] [Indexed: 12/08/2023]
Abstract
PURPOSE OF REVIEW Machine Learning (ML) and Artificial Intelligence (AI) are data-driven techniques to translate raw data into applicable and interpretable insights that can assist in clinical decision making. Some of these tools have extremely promising initial results, earning both great excitement and creating hype. This non-technical article reviews recent developments in ML/AI in epilepsy to assist the current practicing epileptologist in understanding both the benefits and limitations of integrating ML/AI tools into their clinical practice. RECENT FINDINGS ML/AI tools have been developed to assist clinicians in almost every clinical decision including (1) predicting future epilepsy in people at risk, (2) detecting and monitoring for seizures, (3) differentiating epilepsy from mimics, (4) using data to improve neuroanatomic localization and lateralization, and (5) tracking and predicting response to medical and surgical treatments. We also discuss practical, ethical, and equity considerations in the development and application of ML/AI tools including chatbots based on Large Language Models (e.g., ChatGPT). ML/AI tools will change how clinical medicine is practiced, but, with rare exceptions, the transferability to other centers, effectiveness, and safety of these approaches have not yet been established rigorously. In the future, ML/AI will not replace epileptologists, but epileptologists with ML/AI will replace epileptologists without ML/AI.
Collapse
Affiliation(s)
- Wesley T Kerr
- Department of Neurology, University of Pittsburgh, 3471 Fifth Ave, Kaufmann 811.22, Pittsburgh, PA, 15213, USA.
- Department of Biomedical Informatics, University of Pittsburgh, 3471 Fifth Ave, Kaufmann 811.22, Pittsburgh, PA, 15213, USA.
- Department of Neurology, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA.
| | - Katherine N McFarlane
- Department of Neurology, University of Pittsburgh, 3471 Fifth Ave, Kaufmann 811.22, Pittsburgh, PA, 15213, USA
| |
Collapse
|
2
|
Goodkin O, Pemberton HG, Vos SB, Prados F, Das RK, Moggridge J, De Blasi B, Bartlett P, Williams E, Campion T, Haider L, Pearce K, Bargallό N, Sanchez E, Bisdas S, White M, Ourselin S, Winston GP, Duncan JS, Cardoso J, Thornton JS, Yousry TA, Barkhof F. Clinical evaluation of automated quantitative MRI reports for assessment of hippocampal sclerosis. Eur Radiol 2020; 31:34-44. [PMID: 32749588 PMCID: PMC7755617 DOI: 10.1007/s00330-020-07075-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 05/07/2020] [Accepted: 07/15/2020] [Indexed: 02/07/2023]
Abstract
OBJECTIVES Hippocampal sclerosis (HS) is a common cause of temporal lobe epilepsy. Neuroradiological practice relies on visual assessment, but quantification of HS imaging biomarkers-hippocampal volume loss and T2 elevation-could improve detection. We tested whether quantitative measures, contextualised with normative data, improve rater accuracy and confidence. METHODS Quantitative reports (QReports) were generated for 43 individuals with epilepsy (mean age ± SD 40.0 ± 14.8 years, 22 men; 15 histologically unilateral HS; 5 bilateral; 23 MR-negative). Normative data was generated from 111 healthy individuals (age 40.0 ± 12.8 years, 52 men). Nine raters with different experience (neuroradiologists, trainees, and image analysts) assessed subjects' imaging with and without QReports. Raters assigned imaging normal, right, left, or bilateral HS. Confidence was rated on a 5-point scale. RESULTS Correct designation (normal/abnormal) was high and showed further trend-level improvement with QReports, from 87.5 to 92.5% (p = 0.07, effect size d = 0.69). Largest magnitude improvement (84.5 to 93.8%) was for image analysts (d = 0.87). For bilateral HS, QReports significantly improved overall accuracy, from 74.4 to 91.1% (p = 0.042, d = 0.7). Agreement with the correct diagnosis (kappa) tended to increase from 0.74 ('fair') to 0.86 ('excellent') with the report (p = 0.06, d = 0.81). Confidence increased when correctly assessing scans with the QReport (p < 0.001, η2p = 0.945). CONCLUSIONS QReports of HS imaging biomarkers can improve rater accuracy and confidence, particularly in challenging bilateral cases. Improvements were seen across all raters, with large effect sizes, greatest for image analysts. These findings may have positive implications for clinical radiology services and justify further validation in larger groups. KEY POINTS • Quantification of imaging biomarkers for hippocampal sclerosis-volume loss and raised T2 signal-could improve clinical radiological detection in challenging cases. • Quantitative reports for individual patients, contextualised with normative reference data, improved diagnostic accuracy and confidence in a group of nine raters, in particular for bilateral HS cases. • We present a pre-use clinical validation of an automated imaging assessment tool to assist clinical radiology reporting of hippocampal sclerosis, which improves detection accuracy.
Collapse
Affiliation(s)
- Olivia Goodkin
- Centre for Medical Image Computing (CMIC), University College London, London, UK. .,Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, University College London, London, UK.
| | - Hugh G Pemberton
- Centre for Medical Image Computing (CMIC), University College London, London, UK.,Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Sjoerd B Vos
- Centre for Medical Image Computing (CMIC), University College London, London, UK.,Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, University College London, London, UK.,Epilepsy Society MRI Unit, Chalfont St Peter, UK
| | - Ferran Prados
- Centre for Medical Image Computing (CMIC), University College London, London, UK.,Universitat Oberta de Catalunya, Barcelona, Spain
| | - Ravi K Das
- Clinical, Educational and Health Psychology, University College London, London, UK
| | - James Moggridge
- Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, University College London, London, UK.,Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, UK
| | - Bianca De Blasi
- Department of Medical Physics and Bioengineering, University College London, London, UK
| | - Philippa Bartlett
- Epilepsy Society MRI Unit, Chalfont St Peter, UK.,Department of Clinical and Experimental Epilepsy, University College London, London, UK
| | - Elaine Williams
- Wellcome Trust Centre for Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Thomas Campion
- Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, UK
| | - Lukas Haider
- Department of Biomedical Imaging and Image Guided Therapy, Medical University of Vienna, Vienna, Austria.,NMR Research Unit, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Kirsten Pearce
- Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, UK
| | - Nuria Bargallό
- Radiology Department, Hospital Clínic de Barcelona and Magnetic Resonance Image Core Facility, Institut d'Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), Barcelona, Spain
| | - Esther Sanchez
- Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Sotirios Bisdas
- Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, University College London, London, UK.,Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, UK
| | - Mark White
- Digital Services, University College London Hospital, London, UK
| | - Sebastien Ourselin
- Department of Medical Physics and Bioengineering, University College London, London, UK.,School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Gavin P Winston
- Epilepsy Society MRI Unit, Chalfont St Peter, UK.,Department of Clinical and Experimental Epilepsy, University College London, London, UK.,Department of Medicine, Division of Neurology, Queen's University, Kingston, Ontario, Canada
| | - John S Duncan
- Epilepsy Society MRI Unit, Chalfont St Peter, UK.,Department of Clinical and Experimental Epilepsy, University College London, London, UK
| | - Jorge Cardoso
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - John S Thornton
- Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, University College London, London, UK.,Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, UK
| | - Tarek A Yousry
- Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, University College London, London, UK.,Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, UK
| | - Frederik Barkhof
- Centre for Medical Image Computing (CMIC), University College London, London, UK.,Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, University College London, London, UK.,Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, UK.,Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| |
Collapse
|
3
|
Hu WH, Liu LN, Zhao BT, Wang X, Zhang C, Shao XQ, Zhang K, Ma YS, Ai L, Li JJ, Zhang JG. Use of an Automated Quantitative Analysis of Hippocampal Volume, Signal, and Glucose Metabolism to Detect Hippocampal Sclerosis. Front Neurol 2018; 9:820. [PMID: 30337903 PMCID: PMC6180190 DOI: 10.3389/fneur.2018.00820] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 09/11/2018] [Indexed: 12/30/2022] Open
Abstract
Purpose: Magnetic resonance imaging (MRI) and positron emission tomography (PET) with 18F-fluorodeoxyglucose (18FDG) are valuable tools for evaluating hippocampal sclerosis (HS); however, bias may arise during visual analyses. The aim of this study was to evaluate and compare MRI and PET post-processing techniques, automated quantitative hippocampal volume (Q-volume), and fluid-attenuated inversion-recovery (FLAIR) signal (Q-FLAIR) and glucose metabolism (Q-PET) analyses in patients with HS. Methods: We collected MRI and 18FDG-PET images from 54 patients with HS and 22 healthy controls and independently performed conventional visual analyses (CVA) of PET (CVA-PET) and MRI (CVA-MRI) images. During the subsequent quantitative analyses, the hippocampus was segmented from the 3D T1 image, and the mean volumetric, FLAIR intensity and standardized uptake value ratio (SUVR) values of the left and right hippocampus were assessed in each subject. Threshold confidence levels calculated from the mean volumetric, FLAIR intensity and SUVR values of the controls were used to identify healthy subjects or subjects with HS. The performance of the three methods was assessed using receiver operating characteristic (ROC) curves, and the detection rates of CVA-MRI, CVA-PET, Q-volume, Q-FLAIR, and Q-PET were statistically compared. Results: The areas under the curves (AUCs) for the Q-volume, Q-FLAIR, and Q-PET ROC analyses were 0.88, 0.41, and 0.98, which suggested a diagnostic method with moderate, poor, and high accuracy, respectively. Although Q-PET had the highest detection rate among the two CVA methods and three quantitative methods, the difference between Q-volume and Q-PET did not reach statistical significance. Regarding the HS subtypes, CVA-MRI, CVA-PET, Q-volume, and Q-PET had similar detection rates for type 1 HS, and Q-PET was the most sensitive method for detecting types 2 and 3 HS. Conclusions: In MRI or 18FDG-PET images that have been visually assessed by experts, the quantification of hippocampal volume or glucose uptake can increase the detection of HS and appear to be additional valuable diagnostic tools for evaluating patients with epilepsy who are suspected of having HS.
Collapse
Affiliation(s)
- Wen-Han Hu
- Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Li-Na Liu
- Department of Pathology, Beijing Fengtai Hospital, Beijing, China
| | - Bao-Tian Zhao
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xiu Wang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Chao Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xiao-Qiu Shao
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Kai Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yan-Shan Ma
- Department of Neurosurgery, Beijing Fengtai Hospital, Beijing, China
| | - Lin Ai
- Nuclear Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Jun-Ju Li
- Department of Neurosurgery, Hainan General Hospital, Haikou, China
| | - Jian-Guo Zhang
- Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| |
Collapse
|
4
|
Orlowski HLP, Smyth MD, Parsons MS, Dahiya S, Sharifai N, Hildebolt C, Sharma A. Enhancing contrast to noise ratio of hippocampi affected with mesial temporal sclerosis: A case-control study in children undergoing epilepsy surgeries. Clin Neurol Neurosurg 2018; 174:144-148. [PMID: 30241008 DOI: 10.1016/j.clineuro.2018.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 08/27/2018] [Accepted: 09/03/2018] [Indexed: 10/28/2022]
Abstract
OBJECTIVE Detection of mesial temporal sclerosis (MTS) in children with epilepsy is important. We assessed whether an image-processing algorithm (Correlative Image Enhancement, CIE) could facilitate recognition of hippocampal signal abnormality in the presence of MTS by increasing contrast to noise ratio between affected hippocampus and normal gray matter. PATIENTS AND METHODS Baseline coronal FLAIR images from brain MRIs of 27 children with epilepsy who underwent hippocampal resection were processed using CIE. These included 19 hippocampi with biopsy proven MTS and 8 biopsy proven normal hippocampi resected in conjunction with hemispherotomy. We assessed the effect of processing on contrast to noise ratio (CNR) between hippocampus and normal insular gray matter, and on assessment of hippocampal signal abnormality by two masked neuroradiologists. RESULTS Processing resulted in a significant increase in mean CNR (from 3.9 ± 5.3 to 25.3 ± 25.8; P < 0.01) for hippocampi with MTS, with a substantial (>100%) increase from baseline seen in 15/19 (78.9%) cases. Baseline CNR of 1.7 ± 5.3 for normal hippocampi did not change significantly after processing (1.8 ± 5.3; P = 1.00). For one reader, baseline sensitivity (14/19; 73.6%) was unaffected but the specificity improved from 62.5% (5/8) to 100%. An increase in both sensitivity (from 73.6% to 78.9%) and specificity (from 62.5% to 75%) was seen for the second reader. CONCLUSION By enhancing CNR for diseased hippocampi while leaving normal hippocampi relatively unaffected, CIE may improve the diagnostic accuracies of radiologists in detecting MTS-related signal alteration within the affected hippocampus.
Collapse
Affiliation(s)
- Hilary L P Orlowski
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Boulevard, St. Louis, MO 63110, United States.
| | - Matthew D Smyth
- Department of Neurological Surgery, Washington University School of Medicine, 660 South Euclid, Box 8057, St. Louis, MO 63110, United States.
| | - Matthew S Parsons
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Boulevard, St. Louis, MO 63110, United States.
| | - Sonika Dahiya
- Department of Pathology & Immunology, Washington University School of Medicine, 509 S. Euclid Ave, St. Louis, MO 63110, United States.
| | - Nima Sharifai
- Department of Pathology & Immunology, Washington University School of Medicine, 509 S. Euclid Ave, St. Louis, MO 63110, United States.
| | - Charles Hildebolt
- Division of Biostatistics, Washington University School of Medicine, 660 S. Euclid Ave. St. Louis, MO 63110, United States.
| | - Aseem Sharma
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Boulevard, St. Louis, MO 63110, United States.
| |
Collapse
|
5
|
Daoust A, Dodd S, Nair G, Bouraoud N, Jacobson S, Walbridge S, Reich DS, Koretsky A. Transverse relaxation of cerebrospinal fluid depends on glucose concentration. Magn Reson Imaging 2017; 44:72-81. [PMID: 28782676 DOI: 10.1016/j.mri.2017.08.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 07/28/2017] [Accepted: 08/02/2017] [Indexed: 10/19/2022]
Abstract
PURPOSE To evaluate the biophysical processes that generate specific T2 values and their relationship to specific cerebrospinal fluid (CSF) content. MATERIALS AND METHODS CSF T2s were measured ex vivo (14.1T) from isolated CSF collected from human, rat and non-human primate. CSF T2s were also measured in vivo at different field strength in human (3 and 7T) and rodent (1, 4.7, 9,4 and 11.7T) using different pulse sequences. Then, relaxivities of CSF constituents were measured, in vitro, to determine the major molecule responsible for shortening CSF T2 (2s) compared to saline T2 (3s). The impact of this major molecule on CSF T2 was then validated in rodent, in vivo, by the simultaneous measurement of the major molecule concentration and CSF T2. RESULTS Ex vivo CSF T2 was about 2.0s at 14.1T for all species. In vivo human CSF T2 approached ex vivo values at 3T (2.0s) but was significantly shorter at 7T (0.9s). In vivo rodent CSF T2 decreased with increasing magnetic field and T2 values similar to the in vitro ones were reached at 1T (1.6s). Glucose had the largest contribution of shortening CSF T2in vitro. This result was validated in rodent in vivo, showing that an acute change in CSF glucose by infusion of glucose into the blood, can be monitored via changes in CSF T2 values. CONCLUSION This study opens the possibility of monitoring glucose regulation of CSF at the resolution of MRI by quantitating T2.
Collapse
Affiliation(s)
- A Daoust
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States.
| | - S Dodd
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States.
| | - G Nair
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States.
| | - N Bouraoud
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States.
| | - S Jacobson
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States.
| | - S Walbridge
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States.
| | - D S Reich
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States.
| | - A Koretsky
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States.
| |
Collapse
|
6
|
Chen H, Yu G, Wang J, Li F, Li G. Application of T2 relaxometry in lateralization and localization of mesial temporal lobe epilepsy and corresponding comparison with MR volumetry. Acta Radiol 2016; 57:1107-13. [PMID: 26622058 DOI: 10.1177/0284185115617345] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 10/19/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND Magnetic resonance (MR) volumetry is insensitive to subtle mesial temporal sclerosis (MTS), while T2 relaxometry is potential useful in detecting MTS, especially MTS in early course. PURPOSE To explore and compare the feasibility of T2 relaxometry and MR volumetry in evaluation of mesial temporal lobe epilepsy (MTLE) and lateralization of the epileptogenic zone, so as to optimize and enhance lesion depiction. MATERIAL AND METHODS For the 17 unilateral MTLE patients and 14 normal participants, the hippocampus and amygdala were contoured on axial T2-weighted (T2W) images and then co-registered onto T2 relaxation maps. Abnormal is defined as an elevated asymmetric ratio of larger than 2 SD. Visual and quantitative volumetric assessment were combined as outcomes of MR volumetry to distinguish MR-positive and MR-negative lesions. Operative and pathological findings were used as gold standard. RESULTS T2 values of lesions were significantly elevated. In lateralizing the epileptogenic zones, T2 relaxometry yielded an overall accuracy of 94.1% (sensitivity 92.6%, specificity 100%), and MR volumetry yielded an overall accuracy of 82.4% (sensitivity 88.9%, specificity 57.1%), meaning a better performance of T2 relaxometry (P < 0.001, by chi-square test). For pathologically sclerotic structures, most (25/27) were recognized by T2 relaxometry, while 24 of 27 sclerotic structures were detected via MR volumetry. MR volumetry wrongly discerned three normal regions as MTS, while one MR-negative sclerotic hippocampus was detected by T2 relaxometry. CONCLUSION T2 relaxometry is feasible in non-invasive lateralization of epileptogenic zone, and more advantaged than MR volumetry in detecting MR-negative lesions, facilitating prompt diagnosis and longitudinal disease monitoring.
Collapse
Affiliation(s)
- Hui Chen
- Department of Radiology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei, PR China
| | - Guilian Yu
- Reproductive Center, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei, PR China
| | - Jiangtao Wang
- Department of Radiology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei, PR China
| | - Feng Li
- Department of Radiology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei, PR China
| | - Guangming Li
- Department of Radiology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei, PR China
| |
Collapse
|
7
|
Azab M, Carone M, Ying SH, Yousem DM. Mesial Temporal Sclerosis: Accuracy of NeuroQuant versus Neuroradiologist. AJNR Am J Neuroradiol 2015; 36:1400-6. [PMID: 25907519 DOI: 10.3174/ajnr.a4313] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 01/19/2015] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE We sought to compare the accuracy of a volumetric fully automated computer assessment of hippocampal volume asymmetry versus neuroradiologists' interpretations of the temporal lobes for mesial temporal sclerosis. Detecting mesial temporal sclerosis (MTS) is important for the evaluation of patients with temporal lobe epilepsy as it often guides surgical intervention. One feature of MTS is hippocampal volume loss. MATERIALS AND METHODS Electronic medical record and researcher reports of scans of patients with proved mesial temporal sclerosis were compared with volumetric assessment with an FDA-approved software package, NeuroQuant, for detection of mesial temporal sclerosis in 63 patients. The degree of volumetric asymmetry was analyzed to determine the neuroradiologists' threshold for detecting right-left asymmetry in temporal lobe volumes. RESULTS Thirty-six patients had left-lateralized MTS, 25 had right-lateralized MTS, and 2 had bilateral MTS. The estimated accuracy of the neuroradiologist was 72.6% with a κ statistic of 0.512 (95% CI, 0.315-0.710) [moderate agreement, P < 3 × 10(-6)]), whereas the estimated accuracy of NeuroQuant was 79.4% with a κ statistic of 0.588 (95% CI, 0.388-0.787) [moderate agreement, P < 2 × 10(-6)]). This discrepancy in accuracy was not statistically significant. When at least a 5%-10% volume discrepancy between temporal lobes was present, the neuroradiologists detected it 75%-80% of the time. CONCLUSIONS As a stand-alone fully automated software program that can process temporal lobe volume in 5-10 minutes, NeuroQuant compares favorably with trained neuroradiologists in predicting the side of mesial temporal sclerosis. Neuroradiologists can often detect even small temporal lobe volumetric changes visually.
Collapse
Affiliation(s)
- M Azab
- From the Division of Neuroradiology (M.A., S.H.Y., D.M.Y.), The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, Maryland Department of Radiology (M.A.), Suez Canal University, Ismaïlia, Ismailia Governorate
| | - M Carone
- Department of Biostatistics (M.C.), University of Washington, Seattle, Washington
| | - S H Ying
- From the Division of Neuroradiology (M.A., S.H.Y., D.M.Y.), The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - D M Yousem
- From the Division of Neuroradiology (M.A., S.H.Y., D.M.Y.), The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, Maryland
| |
Collapse
|
8
|
Kerr WT, Nguyen ST, Cho AY, Lau EP, Silverman DH, Douglas PK, Reddy NM, Anderson A, Bramen J, Salamon N, Stern JM, Cohen MS. Computer-Aided Diagnosis and Localization of Lateralized Temporal Lobe Epilepsy Using Interictal FDG-PET. Front Neurol 2013; 4:31. [PMID: 23565107 PMCID: PMC3615243 DOI: 10.3389/fneur.2013.00031] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 03/18/2013] [Indexed: 11/13/2022] Open
Abstract
Interictal FDG-PET (iPET) is a core tool for localizing the epileptogenic focus, potentially before structural MRI, that does not require rare and transient epileptiform discharges or seizures on EEG. The visual interpretation of iPET is challenging and requires years of epilepsy-specific expertise. We have developed an automated computer-aided diagnostic (CAD) tool that has the potential to work both independent of and synergistically with expert analysis. Our tool operates on distributed metabolic changes across the whole brain measured by iPET to both diagnose and lateralize temporal lobe epilepsy (TLE). When diagnosing left TLE (LTLE) or right TLE (RTLE) vs. non-epileptic seizures (NES), our accuracy in reproducing the results of the gold standard long term video-EEG monitoring was 82% [95% confidence interval (CI) 69-90%] or 88% (95% CI 76-94%), respectively. The classifier that both diagnosed and lateralized the disease had overall accuracy of 76% (95% CI 66-84%), where 89% (95% CI 77-96%) of patients correctly identified with epilepsy were correctly lateralized. When identifying LTLE, our CAD tool utilized metabolic changes across the entire brain. By contrast, only temporal regions and the right frontal lobe cortex, were needed to identify RTLE accurately, a finding consistent with clinical observations and indicative of a potential pathophysiological difference between RTLE and LTLE. The goal of CADs is to complement - not replace - expert analysis. In our dataset, the accuracy of manual analysis (MA) of iPET (∼80%) was similar to CAD. The square correlation between our CAD tool and MA, however, was only 30%, indicating that our CAD tool does not recreate MA. The addition of clinical information to our CAD, however, did not substantively change performance. These results suggest that automated analysis might provide clinically valuable information to focus treatment more effectively.
Collapse
Affiliation(s)
- Wesley T. Kerr
- Department of Biomathematics, David Geffen School of Medicine, University of California Los AngelesLos Angeles, CA, USA
- Laboratory of Integrative Neuroimaging Technology, Department of Psychiatry, Neuropsychiatric Institute, University of California Los AngelesLos Angeles, CA, USA
| | - Stefan T. Nguyen
- Ahmanson Translational Imaging Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los AngelesLos Angeles, CA, USA
| | - Andrew Y. Cho
- Laboratory of Integrative Neuroimaging Technology, Department of Psychiatry, Neuropsychiatric Institute, University of California Los AngelesLos Angeles, CA, USA
| | - Edward P. Lau
- Laboratory of Integrative Neuroimaging Technology, Department of Psychiatry, Neuropsychiatric Institute, University of California Los AngelesLos Angeles, CA, USA
| | - Daniel H. Silverman
- Ahmanson Translational Imaging Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los AngelesLos Angeles, CA, USA
| | - Pamela K. Douglas
- Laboratory of Integrative Neuroimaging Technology, Department of Psychiatry, Neuropsychiatric Institute, University of California Los AngelesLos Angeles, CA, USA
| | - Navya M. Reddy
- Ahmanson Translational Imaging Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los AngelesLos Angeles, CA, USA
| | - Ariana Anderson
- Laboratory of Integrative Neuroimaging Technology, Department of Psychiatry, Neuropsychiatric Institute, University of California Los AngelesLos Angeles, CA, USA
| | - Jennifer Bramen
- Laboratory of Integrative Neuroimaging Technology, Department of Psychiatry, Neuropsychiatric Institute, University of California Los AngelesLos Angeles, CA, USA
| | - Noriko Salamon
- Department of Neurology, Seizure Disorder Center, University of California Los AngelesLos Angeles, CA, USA
| | - John M. Stern
- Department of Neurology, Seizure Disorder Center, University of California Los AngelesLos Angeles, CA, USA
| | - Mark S. Cohen
- Laboratory of Integrative Neuroimaging Technology, Department of Psychiatry, Neuropsychiatric Institute, University of California Los AngelesLos Angeles, CA, USA
- Laboratory of Integrative Neuroimaging Technology, Departments of Psychiatry, Neurology, Radiology, Biomedical Physics, Psychology and Bioengineering, University of California Los AngelesLos Angeles, CA, USA
| |
Collapse
|
9
|
Farid N, Girard HM, Kemmotsu N, Smith ME, Magda SW, Lim WY, Lee RR, McDonald CR. Temporal lobe epilepsy: quantitative MR volumetry in detection of hippocampal atrophy. Radiology 2012; 264:542-50. [PMID: 22723496 DOI: 10.1148/radiol.12112638] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To determine the ability of fully automated volumetric magnetic resonance (MR) imaging to depict hippocampal atrophy (HA) and to help correctly lateralize the seizure focus in patients with temporal lobe epilepsy (TLE). MATERIALS AND METHODS This study was conducted with institutional review board approval and in compliance with HIPAA regulations. Volumetric MR imaging data were analyzed for 34 patients with TLE and 116 control subjects. Structural volumes were calculated by using U.S. Food and Drug Administration-cleared software for automated quantitative MR imaging analysis (NeuroQuant). Results of quantitative MR imaging were compared with visual detection of atrophy, and, when available, with histologic specimens. Receiver operating characteristic analyses were performed to determine the optimal sensitivity and specificity of quantitative MR imaging for detecting HA and asymmetry. A linear classifier with cross validation was used to estimate the ability of quantitative MR imaging to help lateralize the seizure focus. RESULTS Quantitative MR imaging-derived hippocampal asymmetries discriminated patients with TLE from control subjects with high sensitivity (86.7%-89.5%) and specificity (92.2%-94.1%). When a linear classifier was used to discriminate left versus right TLE, hippocampal asymmetry achieved 94% classification accuracy. Volumetric asymmetries of other subcortical structures did not improve classification. Compared with invasive video electroencephalographic recordings, lateralization accuracy was 88% with quantitative MR imaging and 85% with visual inspection of volumetric MR imaging studies but only 76% with visual inspection of clinical MR imaging studies. CONCLUSION Quantitative MR imaging can depict the presence and laterality of HA in TLE with accuracy rates that may exceed those achieved with visual inspection of clinical MR imaging studies. Thus, quantitative MR imaging may enhance standard visual analysis, providing a useful and viable means for translating volumetric analysis into clinical practice.
Collapse
Affiliation(s)
- Nikdokht Farid
- Department of Radiology, University of California, San Diego, CA 92037, USA
| | | | | | | | | | | | | | | |
Collapse
|
10
|
Abstract
Underlying the exquisite soft tissue contrast provided by magnetic resonance imaging are the inherent biophysical processes of relaxation. Through the intricate relationships between tissue microstructure and biochemistry and the longitudinal and transverse relaxation rates, quantitative measurement of these relaxation parameters is informative of tissue change associated with disease, neural plasticity, and other biological processes. Quantitative imaging studies can further facilitate more detailed characterizations of tissue, providing a more direct link between modern MR imaging and classic histochemical and histological studies. In this chapter, we briefly review the biophysical basis of relaxation, introducing and focusing specifically on the T(1), T(2), and T(2)(*) relaxation times and detail some of the more widely used and clinically feasible techniques for their in vivo measurement. Methods for analyzing relaxation data are covered, and a summary of significant results from reported neuroimaging studies is provided. Finally, the combination of relaxation time data with other quantitative imaging data, including diffusion tensor and magnetization transfer, is examined, with the aim of providing more thorough characterization of brain tissue.
Collapse
Affiliation(s)
- Sean C L Deoni
- Division of Engineering, Brown University, Providence, RI, USA.
| |
Collapse
|
11
|
Crompton DE, Scheffer IE, Taylor I, Cook MJ, McKelvie PA, Vears DF, Lawrence KM, McMahon JM, Grinton BE, McIntosh AM, Berkovic SF. Familial mesial temporal lobe epilepsy: a benign epilepsy syndrome showing complex inheritance. Brain 2010; 133:3221-31. [PMID: 20864493 DOI: 10.1093/brain/awq251] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Temporal lobe epilepsy is the commonest partial epilepsy of adulthood. Although generally perceived as an acquired disorder, several forms of familial temporal lobe epilepsy, with mesial or lateral seizure semiology, have been described. Descriptions of familial mesial temporal lobe epilepsy have varied widely from a benign epilepsy syndrome with prominent déjà vu and without antecedent febrile seizures or magnetic resonance imaging abnormalities, to heterogeneous, but generally more refractory epilepsies, often with a history of febrile seizures and with frequent hippocampal atrophy and high T₂ signal on magnetic resonance imaging. Compelling evidence of a genetic aetiology (rather than chance aggregation) in familial mesial temporal lobe epilepsy has come from twin studies. Dominant inheritance has been reported in two large families, though the usual mode of inheritance is not known. Here, we describe clinical and neurophysiological features of 20 new mesial temporal lobe epilepsy families including 51 affected individuals. The epilepsies in these families were generally benign, and febrile seizure history was infrequent (9.8%). No evidence of hippocampal sclerosis or dysplasia was present on brain imaging. A single individual underwent anterior temporal lobectomy, with subsequent seizure freedom and histopathological evidence of hippocampal sclerosis was not found. Inheritance patterns in probands' relatives were analysed in these families, together with 19 other temporal lobe epilepsy families previously reported by us. Observed frequencies of epilepsies in relatives were lower than predicted by dominant Mendelian models, while only a minority (8/39) of families could be compatible with recessive inheritance. These findings strongly suggest that complex inheritance, similar to that widely accepted in the idiopathic generalized epilepsies, is the usual mode of inheritance in familial mesial temporal lobe epilepsy. This disorder, which appears to be relatively common, and not typically associated with hippocampal sclerosis, is an appropriate target for contemporary approaches to complex disorders such as genome-wide association studies for common genetic variants or deep sequencing for rare variants.
Collapse
Affiliation(s)
- Douglas E Crompton
- Department of Medicine and Epilepsy Research Centre, University of Melbourne, Austin Health, West Heidelberg, Victoria, Australia.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Abstract
The exquisite soft tissue contrast provided by magnetic resonance imaging arises principally from differences in the intrinsic relaxation properties, T1 and T2. Although the intricate relationships that link tissue microstructure and the longitudinal and transverse relaxation times remain to be firmly established, quantitative measurement of these parameters, also referred to as quantitative relaxometry, can be informative of disease-related tissue change, developmental plasticity, and other biological processes. Further, relaxometry studies potentially offer a more detailed characterization of tissue, compared with conventional qualitative or weighted imaging approaches.The purposes of this review were to briefly review the biophysical basis of relaxation, focusing specifically on the T1, T2, and T2* relaxation times, and to detail some of the more widely used and clinically feasible techniques for their in vivo measurement. We will focus on neuroimaging applications, although the methods described are equally well suited to cardiac, abdominal, and musculoskeletal imaging. Potential sources of error, and methods for their correction, are also touched on. Finally, the combination of relaxation time data with other complementary quantitative imaging data, including diffusion tensor imaging, is discussed, with the aim of more thoroughly characterizing brain tissue.
Collapse
Affiliation(s)
- Sean C L Deoni
- Centre for Neuroimaging Research, King's College London, Institute of Psychiatry, London, United Kingdom.
| |
Collapse
|
13
|
McDonald CR, Hagler DJ, Ahmadi ME, Tecoma E, Iragui V, Dale AM, Halgren E. Subcortical and cerebellar atrophy in mesial temporal lobe epilepsy revealed by automatic segmentation. Epilepsy Res 2008; 79:130-8. [PMID: 18359198 DOI: 10.1016/j.eplepsyres.2008.01.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2007] [Revised: 12/07/2007] [Accepted: 01/22/2008] [Indexed: 11/19/2022]
Abstract
PURPOSE To determine the validity and utility of using automated subcortical segmentation to identify atrophy of the hippocampus and other subcortical and cerebellar structures in patients with mesial temporal lobe epilepsy (MTLE). METHODS Volumetric MRIs were obtained on 21 patients with MTLE (11 right, 10 left) and 21 age- and gender-matched healthy controls. Labeling of subcortical and cerebellar structures was accomplished using automated reconstruction software (FreeSurfer). Multivariate analysis of covariance (MANCOVA) was used to explore group differences in intracranial-normalized, age-adjusted volumes and structural asymmetries. Step-wise discriminant function analysis was used to identify the linear combination of volumes that optimized classification of individual subjects. RESULTS Results revealed the expected reduction in hippocampal volume on the side ipsilateral to the seizure focus, as well as bilateral reductions in thalamic and cerebellar gray matter volume. Analysis of structural asymmetries revealed significant asymmetry in the hippocampus and putamen in patients compared to controls. The discriminant function analysis revealed that patients with right and left MTLE were best distinguished from one another using a combination of subcortical volumes that included the right and left hippocampus and left thalamus (91-100% correct classification using cross-validation). DISCUSSION Volumetric data obtained with automated segmentation of subcortical and cerebellar structures approximate data from previous studies based on manual tracings. Our data suggest that automated segmentation can provide a clinically useful means of evaluating the nature and extent of structural damage in patients with MTLE and may increase diagnostic classification of patients, especially when hippocampal atrophy is mild.
Collapse
Affiliation(s)
- Carrie R McDonald
- Department of Psychiatry, University of California, San Diego, United States.
| | | | | | | | | | | | | |
Collapse
|
14
|
Højrup S, Jensen FT, Hokland S, Simonsen C, Christensen T, Frøkiaer J, Pedersen M. Interobserver and within-subject variances of T2-relaxation time and 1H-metabolite ratios in the normal hippocampus. J Neuroradiol 2007; 34:198-204. [PMID: 17568675 DOI: 10.1016/j.neurad.2007.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE To investigate the magnetic resonance (MR) reproducibility of normal hippocampal volume (HV), temporal lobe volume (TLV), transversal relaxation time (T(2)) and (1)H-MR spectroscopy ((1)H-MRS) metabolite ratios. MATERIALS AND METHODS Two sets of HV, TLV, T(2) and MR spectroscopic metabolite signal ratios were determined in 27 healthy volunteers. HV and TLV were measured with a T(1)-weighted MR sequence; whereas T(2) measurements were performed with conventional spin-echo (CSE) and fast spin-echo (FSE) MR imaging sequences. The interobserver and within-subject variances of T(2) measurements were estimated. RESULTS Estimated right and left HV coefficients of variation (CV)=0.13. FSE T(2) measurements showed no significant differences in the interobserver (CV=0.02) and within-subject variances (CV=0.02). Measurements showed no differences in the interobserver (CV=0.02) and within-subject (CV=0.04) variances for the CSE T(2) of the right and left hippocampi. Metabolite ratios between N-acetyl aspartate (NAA) and creatine (Cr), choline (Cho) and creatine, and NAA and choline plus creatine (Cho + Cr) for the right hippocampus were 2.29+/-0.19, 1.52+/-0.14 and 0.91+/-0.05, respectively. Metabolite ratios for the left hippocampus were 2.18+/-0.10, 1.48+/-0.10 and 0.88+/-0.06, respectively. CONCLUSIONS HV, TLV, T(2) and (1)H MRS metabolite ratio measurements showed fair reproducibility with small CVs, and no differences in the interobserver and within-subject variances, including no differences between right and left TLV, and in the right and left T(2).
Collapse
Affiliation(s)
- S Højrup
- MR Research Center, Aarhus University Hospital, 8200 Aarhus, Denmark
| | | | | | | | | | | | | |
Collapse
|
15
|
Geuze E, Vermetten E, Bremner JD. MR-based in vivo hippocampal volumetrics: 2. Findings in neuropsychiatric disorders. Mol Psychiatry 2005; 10:160-84. [PMID: 15356639 DOI: 10.1038/sj.mp.4001579] [Citation(s) in RCA: 272] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Magnetic resonance imaging (MRI) has opened a new window to the brain. Measuring hippocampal volume with MRI has provided important information about several neuropsychiatric disorders. We reviewed the literature and selected all English-language, human subject, data-driven papers on hippocampal volumetry, yielding a database of 423 records. Smaller hippocampal volumes have been reported in epilepsy, Alzheimer's disease, dementia, mild cognitive impairment, the aged, traumatic brain injury, cardiac arrest, Parkinson's disease, Huntington's disease, Cushing's disease, herpes simplex encephalitis, Turner's syndrome, Down's syndrome, survivors of low birth weight, schizophrenia, major depression, posttraumatic stress disorder, chronic alcoholism, borderline personality disorder, obsessive-compulsive disorder, and antisocial personality disorder. Significantly larger hippocampal volumes have been correlated with autism and children with fragile X syndrome. Preservation of hippocampal volume has been reported in congenital hyperplasia, children with fetal alcohol syndrome, anorexia nervosa, attention-deficit and hyperactivity disorder, bipolar disorder, and panic disorder. Possible mechanisms of hippocampal volume loss in neuropsychiatric disorders are discussed.
Collapse
Affiliation(s)
- E Geuze
- Department of Military Psychiatry, Central Military Hospital, Utrecht, Rudolf Magnus Institute of Neuroscience, Mailbox B.01.2.06, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
| | | | | |
Collapse
|
16
|
Okujava M, Schulz R, Ebner A, Woermann FG. Measurement of temporal lobe T2 relaxation times using a routine diagnostic MR imaging protocol in epilepsy. Epilepsy Res 2002; 48:131-42. [PMID: 11823117 DOI: 10.1016/s0920-1211(01)00325-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To determine the applicability of a fast spin-echo (FSE) pulse sequence for T2 relaxation time measurements in diagnostic imaging of temporal lobe epilepsy (TLE) and in epilepsy research. To compare FSE T2-relaxometry to the measurements with multi-echo sequence and visual assessment of MR scans. METHODS MR imaging and T2 relaxometry was performed with widely used 1.5 T scanner only. Fast dual-echo sequence (TE-14/85 ms) and multi-echo pulse sequence were used for T2 measurements. Normal ranges of T2 values in regions of interest in temporal lobe were estimated in 20 healthy controls. Sixty-five patients with intractable focal epilepsy were studied. Fifty-five patients had TLE, three multilobar focal epilepsy and seven extratemporal focal epilepsy. RESULTS T2 measurements with the FSE showed good reproducibility in the test objects and control subjects. In one TLE case unilateral focal T2 changes were not identified visually. T2-relaxometry was more sensitive than visual inspection of MR scans in assessing bilateral hippocampal changes: there were 15 cases with abnormal bilateral T2 values. Visually bilateral changes were detected in six out of these 15 cases (40%). In six cases (40%) only unilateral changes were diagnosed visually, and in three cases (20%) bilateral changes were classified as probable with qualitative evaluation. T2 relaxation time measurement supplied additional objective data in cases with ambiguous hippocampal changes on visual assessment: T2-relaxometry confirmed hippocampal abnormalities in seven cases judged visually as probable. In four cases with the suspicion of hippocampal changes T2 values appeared to be normal. CONCLUSION In TLE patients, images constructed from FSE sequences can be used to estimate T2 relaxation times easily and reliably. T2 measurements are an objective method to diagnose structural changes in the temporal lobe. T2-relaxometry is most helpful to assess bilateral hippocampal abnormalities, and thus might have an impact on estimating postsurgical outcome.
Collapse
Affiliation(s)
- M Okujava
- Institute of Radiology and Interventional Diagnostics, Thevdore Mgvdeli street 13, 380012 Tbilisi, Georgia
| | | | | | | |
Collapse
|
17
|
Juhász C, Nagy F, Muzik O, Watson C, Shah J, Chugani HT. [11C]Flumazenil PET in patients with epilepsy with dual pathology. Epilepsia 1999; 40:566-74. [PMID: 10386525 DOI: 10.1111/j.1528-1157.1999.tb05558.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE Coexistence of hippocampal sclerosis and a potentially epileptogenic cortical lesion is referred to as dual pathology and can be responsible for poor surgical outcome in patients with medically intractable partial epilepsy. [11C]Flumazenil (FMZ) positron emission tomography (PET) is a sensitive method for visualizing epileptogenic foci. In this study of 12 patients with dual pathology, we addressed the sensitivity of FMZ PET to detect hippocampal abnormalities and compared magnetic resonance imaging (MRI) with visual as well as quantitative FMZ PET findings. METHODS All patients underwent volumetric MRI, prolonged video-EEG monitoring, and glucose metabolism PET before the FMZ PET. MRI-coregistered partial volume-corrected PET images were used to measure FMZ-binding asymmetries by using asymmetry indices (AIs) in the whole hippocampus and in three (anterior, middle, and posterior) hippocampal subregions. Cortical sites of decreased FMZ binding also were evaluated by using AIs for regions with MRI-verified cortical lesions as well as for non-lesional areas with visually detected asymmetry. RESULTS Abnormally decreased FMZ binding could be detected by quantitative analysis in the atrophic hippocampus of all 12 patients, including three patients with discordant or inconclusive EEG findings. Decreased FMZ binding was restricted to only one subregion of the hippocampus in three patients. Areas of decreased cortical FMZ binding were obvious visually in all patients. Decreased FMZ binding was detected visually in nonlesional cortical areas in four patients. The AIs for these nonlesional regions with visual asymmetry were significantly lower than those for regions showing MRI lesions (paired t test, p = 0.0075). CONCLUSIONS Visual as well as quantitative analyses of FMZ-binding asymmetry are sensitive methods to detect decreased benzodiazepine-receptor binding in the hippocampus and neocortex of patients with dual pathology. MRI-defined hippocampal atrophy is always associated with decreased FMZ binding, although the latter may be localized to only one sub-region within the hippocampus. FMZ PET abnormalities can occur in areas with normal appearance on MRI, but FMZ-binding asymmetry of these regions is lower when compared with that of lesional areas. FMZ PET can be especially helpful when MRI and EEG findings of patients with intractable epilepsy are discordant.
Collapse
Affiliation(s)
- C Juhász
- Department of Pediatrics, Children's Hospital of Michigan, Wayne State University School of Medicine, Detroit, USA
| | | | | | | | | | | |
Collapse
|
18
|
Pfluger T, Weil S, Weis S, Vollmar C, Heiss D, Egger J, Scheck R, Hahn K. Normative volumetric data of the developing hippocampus in children based on magnetic resonance imaging. Epilepsia 1999; 40:414-23. [PMID: 10219266 DOI: 10.1111/j.1528-1157.1999.tb00735.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE To acquire normative data of the hippocampus and its postnatal growth in 50 children (age, 1 month to 15 years) without epilepsy. METHODS Morphometry of the hippocampus was carried out by using a spoiled FLASH 3D sequence (sagittal orientation), whereas the volume of the brain was assessed with a T2-weighted spin-echo sequence (transverse orientation). The volume of the hippocampus and the brain was determined by following Cavalieri's principle. Growth curves of the brain and hippocampus were fitted to a nonlinear Boltzmann sigmoidal equation. RESULTS Intra-/interobserver coefficient of variation was 2.0/4.9% for hippocampal volume measurements and 2.0/2.1% for brain volumetry. A significant difference in volume was noted between the right and left hippocampus (p < 0.001), with the right side being larger on average by 0.10 cc. Correlation coefficients of growth curves ranged between 0.71 and 0.94. Growth curves demonstrated a faster development of the hippocampus in girls. A steeper slope of hippocampal growth as compared with brain growth was found in girls, whereas in boys, the slope of brain growth was steeper. CONCLUSIONS Our findings will be of help in evaluating vulnerable phases of the hippocampal formation with accelerated growth, thereby leading to a better understanding of the development of hippocampal sclerosis in early childhood.
Collapse
Affiliation(s)
- T Pfluger
- Department of Radiology, Ludwig-Maximilians-University, Munich, Germany
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Kim WJ, Park SC, Lee SJ, Lee JH, Kim JY, Lee BI, Kim DI. The prognosis for control of seizures with medications in patients with MRI evidence for mesial temporal sclerosis. Epilepsia 1999; 40:290-3. [PMID: 10080507 DOI: 10.1111/j.1528-1157.1999.tb00706.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE Mesial temporal sclerosis (MTS) is the most common and important pathology in temporal lobe epilepsy (TLE), and its presence in magnetic resonance imaging (MRI) scans is strongly correlated with a successful surgical outcome. Despite the general assumption that patients with MTS respond poorly to medication, the long-term prognosis for such patients has not yet been investigated. We studied the overall clinical prognosis of patients with MTS and analyzed the factors related to the degree of medical responsiveness. METHODS Case patients were actively followed up at the Yonsei Epilepsy Clinic in Seoul, Korea, for >2 years. A structured interview and a thorough clinical evaluation were conducted. MRI scans, at the field strength of 1.0 or 1.5 Tesla, were performed with T1- and T2-weighted coronal and axial spin-echo images. All coronal slices were < or = 5-mm thick with no gap. Two neurologists and one radiologist determined the presence of MTS in MRIs by visual analysis. RESULTS The MTS group consisted of 104 patients. Of these, 26 (25%) were completely controlled with adequate therapy, and 40 (38%) were intractable, despite aggressive anticonvulsant polytherapy. The remaining 37% had their seizure frequencies reduced by > or = 50%, but were not seizure free. The age of seizure onset was significantly younger in the intractable group than in the well-controlled group. Patients with a history of febrile convulsions or with epileptiform discharges in their electroencephalogram (EEG) had poorer seizure control (p < 0.05) than those who did not. Among the 16 patients who had no previous treatment, five (31%) became seizure free, and two were intractable. CONCLUSIONS Not all patients with MTS are medically intractable; 25% of the patients in our study achieved complete control while receiving medication. Poor seizure control was related to an early age of seizure onset, a history of febrile convulsions, and epileptiform discharges on the EEG.
Collapse
Affiliation(s)
- W J Kim
- Department of Neurology, College of Medicine, Yonsei University, Seoul, Korea
| | | | | | | | | | | | | |
Collapse
|
20
|
Paterson A, Winder J, Bell KE, McKinstry CS. An evaluation of how MRI is used as a pre-operative screening investigation in patients with temporal lobe epilepsy. Clin Radiol 1998; 53:353-6. [PMID: 9630274 DOI: 10.1016/s0009-9260(98)80008-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS A retrospective analysis was carried out of how magnetic resonance imaging (MRI) is used as a pre-operative screening investigation in patients with a clinical diagnosis of medically intractable temporal lobe epilepsy (TLE). Up to 65% of such patients are said to have hippocampal sclerosis (HS). MATERIALS AND METHODS Forty-six patients in a 26-month period underwent MR examination on a 1.5 T scanner according to a routine protocol. Each patient had coronal T1-weighted and oblique coronal T2-weighted scans performed. Hippocampal volume was calculated from the T1-weighted images, the T2-weighted images being assessed for relative hippocampal signal intensity. Each individual patient's medical records were audited. RESULTS Thirty per cent of patients in our study had a diagnosis of HS made on their MR scan. No patient had a diagnosis of HS made without prior clinical evidence of seizure lateralization. Sixty-eight per cent of patients with clinical evidence of a unilateral seizure focus had HS diagnosed by MR scanning. Forty-three per cent of patients did not have clinical evidence of an unilateral seizure focus. It was found that over 25% of patients referred to the unit did not fit the criteria of having medically intractable TLE. Nine per cent of patients had previously stated that they did not want epilepsy surgery. CONCLUSION The lower than expected diagnostic rate of HS in this patient population reflects the broad criteria used in referring patients for imaging studies. This is likely to mirror the initial investigation of these patients outside specialist units where more extensive investigation prior to MRI is available. However, when MRI is used as an initial screening investigation, this study indicates that implementation of simple clinical criteria should significantly reduce the number of unnecessary scans.
Collapse
Affiliation(s)
- A Paterson
- Department of Neuroradiology, Royal Victoria Hospital, Belfast, UK
| | | | | | | |
Collapse
|