¹¹ C-flumazenil PET, volumetric MRI, and quantitative pathology in mesial temporal lobe epilepsy

Abstract

Correction for partial-volume effect allows absolute quantitation of FMZ-PET and increases its sensitivity for detecting abnormalities in TLE due to HS. The lack of correlation between cBZR binding and neuronal density implies that atrophy with neuron loss is not the sole determinant of reduced cBZR binding in patients with mTLE and hippocampal sclerosis.

[11C]Flumazenil PET in Temporal Lobe Epilepsy: Do We Need an Arterial Input Function or Kinetic Modeling?

“…For assessment of medial temporal changes, statistical parametric maps were re-thresholded at P = 0.01 uncorrected, assessed using a medial temporal lobe mask, and significant changes assessed at a threshold of Z > 2.5 and characterized in terms of Z score, extent (k), and coordinates, as described and used previously (Hammers et al, 2001(Hammers et al, , 2002Koepp et al, 1997aKoepp et al, , 1997bKoepp et al, , 2000. This combination of thresholds has a theoretical foundation in the correction for approximately four independent comparisons at the smoothing level of the final SPM (7Z = 2.5 corresponds to a P of 0.0124, that is B0.05/4, a traditional Bonferroni correction for multiple comparisons) and has been empirically validated by approximately yielding the expected false-positive rates in our previous studies.…”

18F-Flumazenil: A γ-Aminobutyric Acid A–Specific PET Radiotracer for the Localization of Drug-Resistant Temporal Lobe Epilepsy

“…One of the major goals of the presurgical evaluation is the identification of the site and extent of the epileptogenic zone. This is usually achieved by the concordance of complementary methods, in particular MR imaging and video-electroencephalographic monitoring, commonly supplemented by 18 F-FDG PET or ictal SPECT (1). However, the area of abnormal metabolism identified by interictal 18 F-FDG PET, or of hyperperfusion on ictal SPECT, often extends well beyond the epileptogenic zone across a large portion of the temporal lobe (and surrounding regions) (2,3).…”

“…This is usually achieved by the concordance of complementary methods, in particular MR imaging and video-electroencephalographic monitoring, commonly supplemented by 18 F-FDG PET or ictal SPECT (1). However, the area of abnormal metabolism identified by interictal 18 F-FDG PET, or of hyperperfusion on ictal SPECT, often extends well beyond the epileptogenic zone across a large portion of the temporal lobe (and surrounding regions) (2,3). Furthermore, the localization rate of 18 F-FDG PET in patients with extratemporal epilepsy is low (4), and obtaining true ictal SPECT injections is resource-intensive and logistically difficult for many centers.…”

“…However, practical limitations of using 11 C-in particular, its short 20-min half-life, necessitating an onsite cyclotron, and the need for arterial blood sampling (8) or multiinjection protocols (8,9) to model the tracer-binding characteristics-have prevented its integration into routine clinical practice. These limitations have motivated the development of 18 F-radiolabeled FMZ conjugates for PET imaging (10,11). 18 F has a significantly longer half-life than 11 C, approximately 110 min, and a superior signal-to-noise ratio, making it more practical for routine clinical use (12).…”

MR-based in vivo hippocampal volumetrics: 2. Findings in neuropsychiatric disorders

“…Hippocampal asymmetry (right minus left hippocampal volume) is significantly correlated with right minus left intracarotid amobarbital memory scores. 92 Hippocampal volumetry has also been used to determine region of interest, [93][94][95] or partial volume correction 96 for PET in temporal lobe epilepsy. A number of studies have also examined methodological issues in hippocampal volumetry in epilepsy such as, optimizing hippocampal volume determination, 17,97 the necessity of hippocampal volume normalization, 98-100 the comparability and reliability of manual and digitizer measurements, 49 the correlation of hippocampal body with total hippocampal volume, 101 the intra-and interobserver variability, 102 and the utility of automated methods.…”