Automated volumetry of hippocampus is useful to confirm unilateral mesial temporal sclerosis in patients with radiologically positive findings

Abstract

Background and purpose We evaluated two methods to identify mesial temporal sclerosis (MTS): visual inspection by experienced epilepsy neuroradiologists based on structural magnetic resonance imaging sequences and automated hippocampal volumetry provided by a processing pipeline based on the FMRIB Software Library. Methods This retrospective study included patients from the epilepsy monitoring unit database of our institution. All patients underwent brain magnetic resonance imaging in 1.5T and 3T scanners with protocols that included thin coronal T2, T1 and fluid-attenuated inversion recovery and isometric T1 acquisitions. Two neuroradiologists with experience in epilepsy and blinded to clinical data evaluated magnetic resonance images for the diagnosis of MTS. The diagnosis of MTS based on an automated method included the calculation of a volumetric asymmetry index between the two hippocampi of each patient and a threshold value to define the presence of MTS obtained through statistical tests (receiver operating characteristics curve). Hippocampi were segmented for volumetric quantification using the FIRST tool and fslstats from the FMRIB Software Library. Results The final cohort included 19 patients with unilateral MTS (14 left side): 14 women and a mean age of 43.4 ± 10.4 years. Neuroradiologists had a sensitivity of 100% and specificity of 73.3% to detect MTS (gold standard, k = 0.755). Automated hippocampal volumetry had a sensitivity of 84.2% and specificity of 86.7% (k = 0.704). Combined, these methods had a sensitivity of 84.2% and a specificity of 100% (k = 0.825). Conclusions Automated volumetry of the hippocampus could play an important role in temporal lobe epilepsy evaluation, namely on confirmation of unilateral MTS diagnosis in patients with radiological suggestive findings.

Diagnosis of mesial temporal sclerosis: sensitivity, specificity and predictive values of the quantitative analysis of magnetic resonance imaging

“…2,9,10 The main imaging findings of MTS are decreases in the size of the hippocampus with signal alteration on T2-weighted sequences. 11–14 Conventional MRI, even with high-resolution thin sequences, has reported low predictive values with a sensitivity of 42% and specificity of 80% in the identification of hippocampal atrophy with a high proportion of false negatives; 2,11 they tend to improve in patients with moderate and severe MTS, where values have been reported of sensitivity up to 93% and specificity of 98%. 13 Different factors associated with the technique and the patients mean that the qualitative analysis is susceptible to false negatives, even for expert neuroradiologists.…”

“…On the other hand, the HVI has shown sensitivity of 55% and specificity of 86% in the identification and lateralisation of MTS in comparison with invasive monitoring. 12–14 This analysis, however, requires the manual delineation of structures, which is time consuming and is susceptible to inter and intra-observer errors. Automated methods have, in recent years, shown promising results in the identification of hippocampal atrophy in comparison with manual techniques.…”

“…9,10 The characteristic findings of this pathology in diagnostic imaging studies are atrophy of the hippocampus, with an increase in the intensity of the signal on T2-weighted sequences. [11][12][13][14] Conventional magnetic resonance imaging (MRI) has reported low predictive values in the identification of hippocampal atrophy. 11 This is more critical in cases in which there is a rotation Department of Diagnostic Imaging, Fundación Valle de Lili, Colombia of the head of the patient, alteration of the signal intensity, or mild or bilateral hippocampal atrophy; there is a high risk of false negatives during qualitative assessment, for even the most expert observers, so that invasive monitoring is still needed in order to determine the lateralisation of the seizure activity.…”

Hippocampal Atrophy in Pediatric Transplant Recipients with Human Herpesvirus 6B

“…Furthermore, the hippocampus has been recognized as a structure consisting of several subfields with distinct histological characteristics [43]. An association between subtle pathophysiological changes in the hippocampus and mild neurological symptoms has been discovered in patients with Parkinson's disease [44] and mesial temporal lobe sclerosis [45] with the latest three-dimensional image analysis techniques. Therefore, evaluation of hippocampal subfields using the same analysis techniques may provide additional information to clarify HHV-6B-associated CNS disease in pediatric HSCT recipients.…”

Ridge–based curvilinear structure detection for identifying road in remote sensing image and backbone in neuron dendrite image

“…Such as the fiber classification, river finding, blood vessel detection, free-way traffic patterns and so on. Silva, Martins [1] extracted the filament and tree like structures which forms the blood vessels in medical images based on the curvilinear structure detection. Shih and Kowalski [2] used curvilinear structures to detect the stars and galaxies formed filament-like structure in cosmological data.…”