Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Multicenter Study
. 2012 Aug 6:12:27.
doi: 10.1186/1471-2342-12-27.

Quantitative and qualitative assessment of structural magnetic resonance imaging data in a two-center study

Sima Chalavi  1 , Andrew Simmons, Hildebrand Dijkstra, Gareth J Barker, A A T Simone Reinders
Affiliations
Multicenter Study

Quantitative and qualitative assessment of structural magnetic resonance imaging data in a two-center study

Sima Chalavi et al. BMC Med Imaging. .

Abstract

Background: Multi-center magnetic resonance imaging (MRI) studies present an opportunity to advance research by pooling data. However, brain measurements derived from MR-images are susceptible to differences in MR-sequence parameters. It is therefore necessary to determine whether there is an interaction between the sequence parameters and the effect of interest, and to minimise any such interaction by careful choice of acquisition parameters. As an exemplar of the issues involved in multi-center studies, we present data from a study in which we aimed to optimize a set of volumetric MRI-protocols to define a protocol giving data that are consistent and reproducible across two centers and over time.

Methods: Optimization was achieved based on data quality and quantitative measures, in our case using FreeSurfer and Voxel Based Morphometry approaches. Our approach consisted of a series of five comparisons. Firstly, a single-center dataset was collected, using a range of candidate pulse-sequences and parameters chosen on the basis of previous literature. Based on initial results, a number of minor changes were implemented to optimize the pulse-sequences, and a second single-center dataset was collected. FreeSurfer data quality measures were compared between datasets in order to determine the best performing sequence(s), which were taken forward to the next stage of testing. We subsequently acquired short-term and long-term two-center reproducibility data, and quantitative measures were again assessed to determine the protocol with the highest reproducibility across centers. Effects of a scanner software and hardware upgrade on the reproducibility of the protocols at one of the centers were also evaluated.

Results: Assessing the quality measures from the first two datasets allowed us to define artefact-free protocols, all with high image quality as assessed by FreeSurfer. Comparing the quantitative test and retest measures, we found high within-center reproducibility for all protocols, but lower between-center reproducibility for some protocols than others. The upgrade showed no important effects.

Conclusions: We were able to determine (for the scanners used in this study) an optimised protocol, which gave the highest within- and between-center reproducibility of those assessed, and give details of this protocol here. More generally, we discuss some of the issues raised by multi-center studies and describe a methodical approach to take towards optimization and standardization, and recommend performing this kind of procedure to other investigators.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Pulsation artefact detected in the acquired images of initial T1-weighted volume protocols dataset with selected protocols C and F. Inconsistencies in phase and amplitude can result in this kind of artefact, which can be reduced by adding flow compensation and/or changing the phase encoding direction.
Figure 2
Figure 2
Average relative mean difference (%) of a) cortical thickness, b) subcortical volumes and c) VBM measurements for Center 1 and Center 2 within-center comparisons. Error bars show the standard deviation of the relative mean difference.
Figure 3
Figure 3
Within-center average absolute cortical thickness differences calculated for each vertex on the left cortical surface (right hemisphere is similar). Comparison between the two centers reveal that while all the protocols are highly reproducible in Center1, in Center2 only protocol C3 shows high reproducibility (less red areas) and the other two protocols show high cortical thickness differences especially in frontal and parietal regions.
Figure 4
Figure 4
Average relative mean difference (%) of a) cortical thickness, b) subcortical volumes and c) VBM measurements for between-center comparisons of the test and retest scans. Error bars show the standard deviation of the relative mean difference.
Figure 5
Figure 5
Between-center average absolute cortical thickness differences calculated for each vertex on the left cortical surface (right hemisphere is similar). While protocol C3 shows low average absolute global cortical thickness differences for both test and retest scans, protocol F2 shows high cortical thickness differences especially in frontal, parietal and cingulate regions of the test scans and protocol F3 reveals high cortical thickness differences in cingulate and parietal regions of the test scans.
Figure 6
Figure 6
Average relative mean difference (%) of a) cortical thickness, b) subcortical volumes and c) VBM measurements comparing Center1 images before and after the upgrade. Error bars show the standard deviation of the relative mean difference. The average relative mean differences of the within Center1 measurements were also added for the comparison purposes.
Figure 7
Figure 7
Average absolute cortical thickness differences between before and after scanner upgrade images in Center1 calculated for each vertex on the left cortical surface (right hemisphere is similar). All the protocols show low average absolute cortical thickness differences and therefore high reproducibility.
See this image and copyright information in PMC

References

    1. Hogg RC, Raggenbass M, Bertrand D. Nicotinic acetylcholine receptors: From structure to brain function. Rev Physiol Biochem Pharmacol. 2003;147:1–46. doi: 10.1007/s10254-003-0005-1. - DOI - PubMed
    1. Hermann BP, Seidenberg M, Bell B. The neurodevelopmental impact of childhood onset temporal lobe epilepsy on brain structure and function and the risk of progressive cognitive effects. Prog Brain Res. 2002;135:429–438. - PubMed
    1. Bremner JD, Vythilingam M, Vermetten E, Southwick SM, McGlashan T, Nazeer A, Khan S, Vaccarino LV, Soufer R, Garg PK, Ng CK, Staib LH, Duncan JS, Charney DS. MRI and PET study of deficits in hippocampal structure and function in women with childhood sexual abuse and posttraumatic stress disorder. Am J Psychiatry. 2003;160(5):924–932. doi: 10.1176/appi.ajp.160.5.924. - DOI - PubMed
    1. Als H, Duffy FH, McAnulty GB, Rivkin MJ, Vajapeyam S, Mulkern RV, Warfield SK, Huppi PS, Butler SC, Conneman N, Fischer C, Eichenwald EC. Early experience alters brain function and structure. Pediatrics. 2004;113(4):846–857. doi: 10.1542/peds.113.4.846. - DOI - PubMed
    1. Sowell ER, Peterson BS, Thompson PM, Welcome SE, Henkenius AL, Toga AW. Mapping cortical change across the human life span. Nat Neurosci. 2003;6(3):309–315. doi: 10.1038/nn1008. - DOI - PubMed

Publication types