Specificity of Volumetric Magnetic Resonance Imaging in Detecting Hippocampal Sclerosis

Watson, Craig; Cendes, Fernando; Fuerst, Darren R.; Dubeau, François; Williamson, Bill; Evans, Allan; Andermann, Frédérick

doi:10.1001/archneur.1997.00550130049015

Cited by 56 publications

(28 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The improved accuracy of syndrome classification by using ictal video EEG monitoring is unquestioned (16); and (c) use of child versus adult control data, as discussed earlier. As in adult studies (3,4) that found a high sensitivity and specificity of HA in highly selective presurgical patients, we replicated this in a childhood group with intractable epilepsy. Although of few members, our surgical group supports these findings with HA always present, with histologic evidence of MTS.…”

Section: Hippocampal Asymmetry Versus Epilepsy Syndromesupporting

confidence: 70%

See 1 more Smart Citation

ILAE‐Defined Epilepsy Syndromes in Children: Correlation with Quantitative MRI

et al. 1998

View full text Add to dashboard Cite

Summary: Purpose:The role of quantitative magnetic resonance imaging (MRI) in evaluation of childhood epilepsy remains poorly defined, with minimal published data. Previous work from our center questioned the specificity of hippocampal asymmetry (HA) in an outpatient group whose epilepsy was defined by using clinical and interictal data only. By using childhood volunteer controls and defining epilepsy syndromes using video-EEG monitoring, we readdressed the utility of HA in differentiating mesial temporal lobe epilepsy (MTLE) from other partial and generalized epileptic syndromes in children.Methods: Seventy children were enrolled; entry criteria were age younger than 18 years with predominant seizure type recorded on video-EEG telemetry with volutnetric MRI in all cases. Thirty healthy child volunteers had volumetric MRI. Epilepsy syndrome classification was according to ILAE.Results: Control data revealed symmetric hippocampi, mean smallernarger ratio of 0.96 (0.95-0.97,95% CI) with no gender or rightneft predominance. Overall 23% of patients had significant HA. Mean hippocampal ratio for MTLE was 0.78 (95% CI, 0.70-0.86), significantly lower than controls and from all other epilepsy syndromes. HA was highly specific (85%) to the syndrome of MTLE. Other potential epileptogenic lesions were found in 27 (39%) patients, lowest yield in frontal and mesial temporal syndromes. Dual pathology was present in 10% of patients. There was no significant association between HA and risk factors. Conclusions:In this study, we found that HA in children with a well-defined epilepsy syndrome is highly sensitive and specific for MTLE. Whether this will correlate with surgical outcome, as in adults, is the subject of ongoing study.

show abstract

Section: Hippocampal Asymmetry Versus Epilepsy Syndromesupporting

confidence: 70%

“…Hippocampal asymmetry (HA) remains unsurpassed as a neuroimaging marker for mesial temporal sclerosis (MTS), with adult studies (1)(2)(3)(4) concluding that it is highly sensitive and specific. Quantitative magnetic resonance imaging (MRI) was more sensitive than visual analysis and T, relaxometry in detecting MTS in an adult study by Kuzniecky et al (1).…”

mentioning

confidence: 99%

ILAE‐Defined Epilepsy Syndromes in Children: Correlation with Quantitative MRI

et al. 1998

View full text Add to dashboard Cite

show abstract

“…MRI is typically characterized by hippocampal atrophy and signal increase in T2-weighted images (4244) and FLAIR (45). MRI hippocampal atrophy, as determined by visual analysis or volumetric assessment, has been shown to correlate well with the presence of MTS (46)(47)(48)(49)(50) and is predictive of good outcome after temporal lobectomy (43,(51)(52)(53). Figure 1 illustrates a case with unequivocal right MTS on MRI.…”

Section: Unilateral Mtsmentioning

confidence: 99%

Temporal Lobe Epilepsy: When Are Invasive Recordings Needed?

2000

View full text Add to dashboard Cite

Summary:Temporal lobe epilepsy (TLE) is the most common type of medically intractable partial epilepsy amenable to surgery. In the majority of cases, the underlying pathology in temporal lobe epilepsy is mesial temporal sclerosis (MTS). Whereas historically invasive recordings were required for most epilepsy surgeries, indications have dramatically changed since the introduction of high-resolution MRI, which uncovers structural lesions in a high percentage of cases. No invasive recordings are required to perform a temporal lobectomy in patients with intractable epilepsy who have structural imaging suggesting unilateral MTS and concordant interictal and ictal surface EEG recordings, functional imaging, and clinical findings. Invasive testing is needed if there is evidence of bitemporal MTS on structural imaging and/or electrophysiologically, and additional information from functional imaging, neuropsychology, and the intracarotid amobarbital (Wada) test also does not help to lateralize the epileptogenic zone. Depth electrodes can be particularly helpful in this setting. However, no surgery is indicated, even without invasive recordings, if bitemporalindependent seizures are recorded by surface EEG and all additional testing is inconclusive. Other etiologies of TLE such as a tumor, vascular malformation, encephalomalacia, or congenital developmental abnormality account for about 30% of all patients who undergo epilepsy surgery. Epilepsy surgery is indicated after limited electrophysiologic investigations if neuroimaging and electrophysiology converge. However, approaches for resection in lesional temporal lobe epilepsy vary among centers. Completeness of resection is crucial and invasive recordings may be needed to guide the resection by mapping eloquent cortex and/or to determine the extent of the non-MRI-visible epileptogenic area. Specific approaches for the different pathologies are discussed because there is evidence that the relationship between the lesions visible on MRI and the epileptogenic zone varies among lesions of different pathologies, and therefore variable surgical strategies must be applied. Key Words: Temporal lobe-Epilepsy-Electrodes, implanted-Magnetic resonance imaging-Brain neoplasms. HISTORICAL PERSPECTIVES: INVASIVE RECORDINGS FOR EPILEPSY SURGERYThe pioneers of epilepsy surgery utilized clinical findings and seizure semiology to localize the epilepsy and to guide the neurosurgical intervention. This is illustrated by Victor Horsley's first neurosurgical intervention at Queens Square in 1886. The patient was a 22-year-old Scotsman who had a posttraumatic epilepsy. He had very frequent focal motor seizures characterized by a clear march. The diagnosis of "scar involving the hinder end of the superior frontal sulcus" was made according to the ictal semiology and the seizures stopped after surgical removal of the scar. Apart from semiologic analysis of the seizures, additional information was obtained by intraoperative cortical stimulations to reproduce the patient's seizure semiology and to ...

show abstract

“…2,4,5,10,28,34,38,39 Diagnosis of MTS requires structural MRI and has high prognostic value for predicting whether a temporal lobe resection will reduce seizures and improve quality of life. 4,13,16,23,31,34,35,39 However, many areas of the world with the highest prevalence of TLE 3,30 have no or limited access to MRI.…”

Section: Discussionmentioning

confidence: 99%

Volumetric brain analysis in neurosurgery: Part 3. Volumetric CT analysis as a predictor of seizure outcome following temporal lobectomy

Mandell¹,

Hill

Nguyen³

et al. 2015

PED

View full text Add to dashboard Cite

OBJECT The incidence of temporal lobe epilepsy (TLE) due to mesial temporal sclerosis (MTS) can be high in developing countries. Current diagnosis of MTS relies on structural MRI, which is generally unavailable in developing world settings. Given widespread effects on temporal lobe structure beyond hippocampal atrophy in TLE, the authors propose that CT volumetric analysis can be used in patient selection to help predict outcomes following resection. METHODS Ten pediatric patients received preoperative CT scans and temporal resections at the CURE Children's Hospital of Uganda. Engel classification of seizure control was determined 12 months postoperatively. Temporal lobe volumes were measured from CT and from normative MR images using the Cavalieri method. Whole brain and fluid volumes were measured using particle filter segmentation. Linear discrimination analysis (LDA) was used to classify seizure outcome by temporal lobe volumes and normalized brain volume. RESULTS Epilepsy patients showed normal to small brain volumes and small temporal lobes bilaterally. A multivariate measure of the volume of each temporal lobe separated patients who were seizure free (Engel Class IA) from those with incomplete seizure control (Engel Class IB/IIB) with LDA (p < 0.01). Temporal lobe volumes also separate normal subjects, patients with Engel Class IA outcomes, and patients with Class IB/IIB outcomes (p < 0.01). Additionally, the authors demonstrated that age-normalized whole brain volume, in combination with temporal lobe volumes, may further improve outcome prediction (p < 0.01). CONCLUSIONS This study shows strong evidence that temporal lobe and brain volume can be predictive of seizure outcome following temporal lobe resection, and that volumetric CT analysis of the temporal lobe may be feasible in lieu of structural MRI when the latter is unavailable. Furthermore, since the authors' methods are modality independent, these findings suggest that temporal lobe and normative brain volumes may further be useful in the selection of patients for temporal lobe resection when structural MRI is available.

show abstract

Specificity of Volumetric Magnetic Resonance Imaging in Detecting Hippocampal Sclerosis

Abstract: Seizures originating at extrahippocampal sites do not cause gliosis, cell loss, or atrophy of medial temporal structures. Significant reduction in hippocampal volumes is a specific marker for HS.

Cited by 56 publications

References 35 publications

ILAE‐Defined Epilepsy Syndromes in Children: Correlation with Quantitative MRI

ILAE‐Defined Epilepsy Syndromes in Children: Correlation with Quantitative MRI

Temporal Lobe Epilepsy: When Are Invasive Recordings Needed?

Volumetric brain analysis in neurosurgery: Part 3. Volumetric CT analysis as a predictor of seizure outcome following temporal lobectomy

Contact Info

Product

Resources

About