Using visual scales to determine brain atrophy subtypes in Alzheimer’s Disease

AD subtypes based on patterns of brain atrophy. Regional atrophy was measured with the MTA, PA, and GCA-F visual rating scales based only on T1-weighted images. In the 3 visual rating scales, a score of zero denotes no atrophy, whereas scores from 1 to 3 (PA and GCA-F) or 4 (MTA) indicate an increasing degree of atrophy. The typical AD subtype was defined as abnormal MTA together with abnormal PA and/or abnormal GCA-F. The limbic-predominant subtype was defined as abnormal MTA alone with normal PA and GCA-F. The hippocampal-sparing subtype included abnormal PA and/or abnormal GCA-F but normal MTA. The minimal atrophy subtype was defined as normal scores in MTA, PA, and GCA-F. The figure shows examples of each subtype in axial and coronal sections of the brain. AD, Alzheimer’s disease; MTA, medial temporal atrophy scale; PA, posterior atrophy scale; GCA-F, global cortical atrophy scale – frontal subscale; A, anterior part of the brain; P, posterior part of the brain; R, right; L, left.

Reference: https://doi.org/10.1159/000515322

Medial temporal atrophy in preclinical dementia: visual and automated assessment during six year follow-up

Medial temporal lobe (MTL) atrophy is an important morphological marker of many dementias and is closely related to cognitive decline. In this study we aimed to characterize longitudinal progression of MTL atrophy in 93 individuals with subjective cognitive decline and mild cognitive impairment followed up over six years, and to assess if clinical rating scales are able to detect these changes. All MRI images were visually rated according to Scheltens' scale of medial temporal atrophy (MTA) by two neuroradiologists and AVRA, a software for automated MTA ratings. The images were also segmented using FreeSurfer's longitudinal pipeline in order to compare the MTA ratings to volumes of the hippocampi and inferior lateral ventricles. We found that MTL atrophy rates increased with CSF biomarker abnormality, used to define preclinical stages of Alzheimer's Disease. Both AVRA's and the radiologists' MTA ratings showed a similar longitudinal trajectory as the subcortical volumes, suggesting that visual rating scales provide a valid alternative to automatic segmentations. While the MTA scores from each radiologist showed strong correlations to subcortical volumes, the inter-rater agreement was low. We conclude that the main limitation of quantifying MTL atrophy with visual ratings in clinics is the subjectiveness of the assessment.

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Parietal atrophy score on magnetic resonance imaging of the brain in normally aging people

Aim: Our intention was to create a simple visual evaluation of parietal atrophy on MRI of the brain useful in identifying neurodegenerative dementias, especially Alzheimer‘s disease. We assessed the changes of the parietal regions dur ing natural aging. Patients and methods: We created a new rat ing scale that we named the Parietal atrophy score. This method is based on semiquantitative scoring of three structures on coronal slices in the entire parietal lobe: parietal gyri, sulcus cingularis posterior and precuneus. Each structure was rated accord ing to the visual classification size as 0 – a normal size without atrophy, 1 – a borderline finding or 2 – a considerable atrophy. These ratings were sum marized into one score for each hemisphere and then these two were integrated into one score for the entire brain. Using a visual rating scale, we clas sified the parietal regions in 74 elderly subjects with a normal Mini-Mental State Examination score (29 ± 1 point) with a wide range of ages between 48–87 years. Results: Increas ing age is as sociated with a mild progression of the parietal lobe atrophy (r = 0.2; p = 0.05). The over all score of the parietal tissue was not as sociated with education, gender or hand dominance. Conclusion: Our new visual rating system of parietal atrophy is an easy and fast method for use in clinical practice. Natural aging is accompanied with negligible parietal atrophic changes. Parietal atrophy score on magnetic resonance imaging of the brain in normally aging people.

• DOI: 
• 10.14735/amcsnn2018414

A ‘Comprehensive Visual Rating Scale’ for predicting progression to dementia in patients with mild cognitive impairment

Background Numerous efforts have been made to identify biomarkers for predicting the progression of dementia in patients with mild cognitive impairment (MCI), and recently, a comprehensive visual rating scale (CVRS) based on magnetic resonance imaging (MRI) has been validated to assess structural changes in the brain of elderly patients. Based on this, the present study investigated the use of CVRS for predicting dementia and elucidated its association with cognitive change in patients with MCI over a three-year follow-up. Methods We included 340 patients with MCI with more than one follow-up visit. Data were obtained from the Alzheimer’s disease Neuroimaging Initiative study. We assessed all the patients using CVRS and determined their progression to dementia during a follow-up period of over 3 years. The cox proportional hazards model was used to analyze hazard ratios (HRs) of CVRS for disease progression. Further, multiple cognitive measures of the patients over time were fitted using the random effect model to assess the effect of initial CVRS score on subsequent cognitive changes. Results Of 340 patients, 69 (20.2%) progressed to dementia and the median baseline score (interquartile range) of CVRS significantly differed between stable MCI and progressive MCI (9 (5–13) vs 13 (8–17), p<0.001). The initial CVRS score was independently associated with an increased risk of progression to dementia (HR 1.123, 95% confidence interval [CI] 1.059–1.192). From 12 to 24 months, the effect of the interaction between CVRS and interval of follow-up visit on cognitive performance achieved significance (p<0.001). Conclusions Baseline CVRS predicted the progression to dementia in patients with MCI, and was independently associated with longitudinal cognitive decline.

Reference: Jang J-W, Park JH, Kim S, Park YH, Pyun J-M, Lim J-S, et al. (2018) A ‘Comprehensive Visual Rating Scale’ for predicting progression to dementia in patients with mild cognitive impairment. PLoS ONE 13(8): e0201852. https://doi.org/10.1371/journal.pone.0201852

New MRI visual rating scales

Six visual rating scales, three alreary described: medial temporal, posterior, anterior temporal and three new/addapted: orbito-frontal, anterior cingulate and fronto-insula) were assessed in this study

Time to perform visual rating
Mean time to perform and record all six visual rating scales based on three raters assessing the subset study population ( n = 80) was 2.9 ± 1.3 min. Individual rater means and standard deviations were 2.7 ± 1.1, 2.4 ± 1.0 and 3.6 ± 1.6 min.

Inter-rater reliability of visual rating scores
Single measure and average measure ICC results for each scale are shown in Supplementary Table 1 . For the single measures ICC values, representing the reliability of each scale at the level of the individual rater, the MTA scale performed best overall, with very similar results achieved with two raters assessing all 257 scans, and four raters scoring 80 scans [ICC(2,1) ≥ 0.79]. The PA, OF and FI scales also demonstrated good reliability [ICC(2,1) ≥0.71] based on two raters assessing the total study population; reliability was slightly reduced when performed by four raters in the subset population [ICC(2,1) ≥ 0.58]. The reliability of the AC scale was lowest overall [ICC(2,1) range = 0.49–0.62]. As expected, the reliability based on mean rater scores was consistently greater for all scales [ICC(2,k) ≥ 0.73]. There were no material differences in reliability based on the larger or smaller population samples for any scale with the exception of the AT and AC scales, which were less reliable in the larger population sample.

Correlation of grey matter volume with visual rating scores
Voxel-based morphometry analysis revealed a negative partial correlation of higher visual rating score with lower grey matter density for all visual rating scales. 

Reference:

Lorna Harper, Giorgio G. Fumagalli, Frederik Barkhof, Philip Scheltens, John T. O’Brien, Femke Bouwman, Emma J. Burton, Jonathan D. Rohrer, Nick C. Fox, Gerard R. Ridgway, Jonathan M. Schott; MRI visual rating scales in the diagnosis of dementia: evaluation in 184 post-mortem confirmed cases. Brain 2016; 139 (4): 1211-1225. doi: 10.1093/brain/aww005https://academic.oup.com/brain/article-lookup/doi/10.1093/brain/aww005

Related publications: BALI: An MRI-Based Semiquantitative Index for the Evaluation of Brain Atrophy and Lesions

Categorizing and grading criteria of the BALI

Categories Criteria
GM-SV (gray matter lesions and small vessels) 0 = absence; 1 = punctuate foci in gray matter or multiple small vessels in subcortical area; 2 = beginning confluence of foci in gray matter or diffuse small vessels in subcortical area; 3 = large confluent lesions in gray matter (rare, evidence for stroke-related malacia foci)
PV (periventricular lesions) 0 = absence; 1 = ‘caps’ or pencil-thin lining; 2 = smooth ‘halo’; 3 = irregular periventricular abnormal signal intensities extending into the deep white matter
DWM (deep white matter lesions) 0 = absence; 1 = punctuate foci; 2 = beginning of confluence foci; 3 = large confluent areas; 4 = large confluent white matter areas involving all cerebral lobes; 5 = complete confluent white matter disease
BG (basal ganglia and surrounding area lesions) 0 = absence; 1 = 1 focal lesion; 2 = >1 focal lesion; 3 = large confluent lesions IT (infratentorial region lesions) 0 = absence; 1 = 1 focal lesion; 2 = >1 focal lesion; 3 = large confluent lesions
GA (global atrophy) 0 = no obvious atrophy; 1 = mild atrophy; 2 = moderate atrophy; 3 = severe atrophy
Other lesions 0 = no other kind of disease; 1 = any 1 kind of brain neoplasm, deformation or trauma; 2 = any 2 kinds of brain neoplasm, deformation or trauma; 3 = simultaneous presence of brain neoplasm, deformation and trauma

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