Fully-Automated Volumetric MRI with Normative Ranges: Translation to Clinical Practice

Abstract

Abstract.Neurodegenerative disorders, such as Alzheimer's disease (AD), are associated with characteristic patterns of neuropathological spread in the brain. Disease progression is usually accompanied by regional atrophy that can be detected noninvasively using structural magnetic resonance imaging (MRI). A wealth of data has demonstrated the value of quantitative measurements of regional atrophy in AD, suggesting that volumetric MRI (vMRI) may be a useful clinical tool. vMRI provides biological evidence of neurodegenerative disease in patients with cognitive impairment. However, several hurdles impede implementation of vMRI in clinical practice. These include a lack of standardized MRI acquisition protocols, spatial distortions in MRI data, labor-intensive vMRI methods susceptible to interoperator variability, a lack of normative ranges for volume measures, and difficulty integrating vMRI in clinical workflow. Advances in vMRI have resulted from multi-institutional studies of brain imaging, such as the Alzheimer's Disease Neuroimaging Initiative (ADNI), and help address these challenges. New, fully-automated measures of brain structure volumes coupled with large, multi-center studies using standardized MRI protocols now allow the development of age-adjusted normative ranges for vMRI. Such advances are critical for providing physicians a framework for assessing the pattern and degree of regional atrophy in a patient's brain and applying vMRI in clinical practice.

3T MRI Quantification of Hippocampal Volume and Signal in Mesial Temporal Lobe Epilepsy Improves Detection of Hippocampal Sclerosis

“…However, a good correlation of volume and signal abnormalities detected by quantification analysis and histopathology of HS has been previously demonstrated. 27 Also, in our group of patients, the laterality of abnormal hippocampal volume and signal was highly concordant with the laterality of the epileptic focus defined by EEG recordings. Currently, most studies of hippocampal volumetry apply manual hippocampal delimitation, and whether manual 28 or automatic analysis has higher sensitivity and specificity is still debatable.…”

“…Although FreeSurfer software is not approved for clinical use by the US Food and Drug Administration, as far as we know, there is at least 1 software approved for automated volumetric analyses of brain MRI. 27 However, this has only been evaluated for the detection of hippocampal abnormalities on 1.5T scanners. 13 In 1.5T MRI, a good correlation of volume and signal abnormalities detected by quantification analysis and histopathology of HS has been demonstrated.…”

Mesial Temporal Sclerosis: Accuracy of NeuroQuant versus Neuroradiologist

“…[10][11][12] Figure 2 provides a depiction of the distribution of observed relative asymmetry indices, defined as right volume Ϫ left volume/left volume. The NeuroQuant mean asymmetry index among healthy patients was estimated to be 2.1% (95% CI, Ϫ2.1-6.2) in our study: This asymmetry was not significantly different from zero.…”

“…The steps involved include sequence-checking to ensure that appropriate high-resolution and contrast image parameters are performed, correction for field/gradient inhomogeneities, removal of the overlying calvaria, alignment to the probabilistic atlas of stereotypical anatomy, and segmented volumetry of predetermined anatomic areas derived from multiple subjects of multiple age groups (Brewer et al). [10][11][12][13] We sought to assess the value of NeuroQuant volumetry of the temporal lobe in patients with MTS with the added goal of trying to determine the difference in right and left hippocampal volumes that can be detected by experienced neuroradiologists in the clinical assessment of patients with temporal lobe epilepsy. We hypothesized that because radiologists assess the hippocampi for other imaging findings above and beyond volume loss alone, the neuroradiologist's determination of the correct side of the MTS would be more accurate than basic NeuroQuant volumetry.…”

Demensdiagnostikk - automatisert kvantifisering av hjernestrukturer

“…Ikke-automatisert (manuell) volumetrisk måling er tidkrevende og av den grunn tungvint å anvende i klinisk praksis. Neuroquant er en av flere automatiserte metoder som er utviklet for bruk i klinisk praksis (11)(12)(13). Normdata er hentet fra The Alzheimer's Disease Neuroimaging Initiative (ADNI) (19).…”