Longitudinal monitoring of amyotrophic lateral sclerosis by diffusion tensor imaging: Power calculations for group studies
IntroductionDiffusion tensor imaging (DTI) can be used to map disease progression in amyotrophic lateral sclerosis (ALS) and therefore is a promising candidate for a biomarker in ALS. To this end, longitudinal study protocols need to be optimized and validated regarding group sizes and time interval...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2022-08-01
|
| Series: | Frontiers in Neuroscience |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/fnins.2022.929151/full |
| _version_ | 1811299430769360896 |
|---|---|
| author | Anna Behler Dorothée Lulé Albert C. Ludolph Albert C. Ludolph Jan Kassubek Jan Kassubek Hans-Peter Müller |
| author_facet | Anna Behler Dorothée Lulé Albert C. Ludolph Albert C. Ludolph Jan Kassubek Jan Kassubek Hans-Peter Müller |
| author_sort | Anna Behler |
| collection | DOAJ |
| description | IntroductionDiffusion tensor imaging (DTI) can be used to map disease progression in amyotrophic lateral sclerosis (ALS) and therefore is a promising candidate for a biomarker in ALS. To this end, longitudinal study protocols need to be optimized and validated regarding group sizes and time intervals between visits. The objective of this study was to assess the influences of sample size, the schedule of follow-up measurements, and measurement uncertainties on the statistical power to optimize longitudinal DTI study protocols in ALS.Patients and methodsTo estimate the measurement uncertainty of a tract-of–interest-based DTI approach, longitudinal test-retest measurements were applied first to a normal data set. Then, DTI data sets of 80 patients with ALS and 50 healthy participants were analyzed in the simulation of longitudinal trajectories, that is, longitudinal fractional anisotropy (FA) values for follow-up sessions were simulated for synthetic patient and control groups with different rates of FA decrease in the corticospinal tract. Monte Carlo simulations of synthetic longitudinal study groups were used to estimate the statistical power and thus the potentially needed sample sizes for a various number of scans at one visit, different time intervals between baseline and follow-up measurements, and measurement uncertainties.ResultsFrom the simulation for different longitudinal FA decrease rates, it was found that two scans per session increased the statistical power in the investigated settings unless sample sizes were sufficiently large and time intervals were appropriately long. The positive effect of a second scan per session on the statistical power was particularly pronounced for FA values with high measurement uncertainty, for which the third scan per session increased the statistical power even further.ConclusionWith more than one scan per session, the statistical power of longitudinal DTI studies can be increased in patients with ALS. Consequently, sufficient statistical power can be achieved even with limited sample sizes. An improved longitudinal DTI study protocol contributes to the detection of small changes in diffusion metrics and thereby supports DTI as an applicable and reliable non-invasive biomarker in ALS. |
| first_indexed | 2024-04-13T06:35:47Z |
| format | Article |
| id | doaj.art-a476192714e441a8b381a6a182d4b149 |
| institution | Directory Open Access Journal |
| issn | 1662-453X |
| language | English |
| last_indexed | 2024-04-13T06:35:47Z |
| publishDate | 2022-08-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Neuroscience |
| spelling | doaj.art-a476192714e441a8b381a6a182d4b1492022-12-22T02:57:56ZengFrontiers Media S.A.Frontiers in Neuroscience1662-453X2022-08-011610.3389/fnins.2022.929151929151Longitudinal monitoring of amyotrophic lateral sclerosis by diffusion tensor imaging: Power calculations for group studiesAnna Behler0Dorothée Lulé1Albert C. Ludolph2Albert C. Ludolph3Jan Kassubek4Jan Kassubek5Hans-Peter Müller6Department of Neurology, University of Ulm, Ulm, GermanyDepartment of Neurology, University of Ulm, Ulm, GermanyDepartment of Neurology, University of Ulm, Ulm, GermanyDeutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Ulm, GermanyDepartment of Neurology, University of Ulm, Ulm, GermanyDeutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Ulm, GermanyDepartment of Neurology, University of Ulm, Ulm, GermanyIntroductionDiffusion tensor imaging (DTI) can be used to map disease progression in amyotrophic lateral sclerosis (ALS) and therefore is a promising candidate for a biomarker in ALS. To this end, longitudinal study protocols need to be optimized and validated regarding group sizes and time intervals between visits. The objective of this study was to assess the influences of sample size, the schedule of follow-up measurements, and measurement uncertainties on the statistical power to optimize longitudinal DTI study protocols in ALS.Patients and methodsTo estimate the measurement uncertainty of a tract-of–interest-based DTI approach, longitudinal test-retest measurements were applied first to a normal data set. Then, DTI data sets of 80 patients with ALS and 50 healthy participants were analyzed in the simulation of longitudinal trajectories, that is, longitudinal fractional anisotropy (FA) values for follow-up sessions were simulated for synthetic patient and control groups with different rates of FA decrease in the corticospinal tract. Monte Carlo simulations of synthetic longitudinal study groups were used to estimate the statistical power and thus the potentially needed sample sizes for a various number of scans at one visit, different time intervals between baseline and follow-up measurements, and measurement uncertainties.ResultsFrom the simulation for different longitudinal FA decrease rates, it was found that two scans per session increased the statistical power in the investigated settings unless sample sizes were sufficiently large and time intervals were appropriately long. The positive effect of a second scan per session on the statistical power was particularly pronounced for FA values with high measurement uncertainty, for which the third scan per session increased the statistical power even further.ConclusionWith more than one scan per session, the statistical power of longitudinal DTI studies can be increased in patients with ALS. Consequently, sufficient statistical power can be achieved even with limited sample sizes. An improved longitudinal DTI study protocol contributes to the detection of small changes in diffusion metrics and thereby supports DTI as an applicable and reliable non-invasive biomarker in ALS.https://www.frontiersin.org/articles/10.3389/fnins.2022.929151/fullAmyotrophic Lateral SclerosisDiffusion Tensor Imaginglongitudinal designstatistical powerstudy optimization |
| spellingShingle | Anna Behler Dorothée Lulé Albert C. Ludolph Albert C. Ludolph Jan Kassubek Jan Kassubek Hans-Peter Müller Longitudinal monitoring of amyotrophic lateral sclerosis by diffusion tensor imaging: Power calculations for group studies Frontiers in Neuroscience Amyotrophic Lateral Sclerosis Diffusion Tensor Imaging longitudinal design statistical power study optimization |
| title | Longitudinal monitoring of amyotrophic lateral sclerosis by diffusion tensor imaging: Power calculations for group studies |
| title_full | Longitudinal monitoring of amyotrophic lateral sclerosis by diffusion tensor imaging: Power calculations for group studies |
| title_fullStr | Longitudinal monitoring of amyotrophic lateral sclerosis by diffusion tensor imaging: Power calculations for group studies |
| title_full_unstemmed | Longitudinal monitoring of amyotrophic lateral sclerosis by diffusion tensor imaging: Power calculations for group studies |
| title_short | Longitudinal monitoring of amyotrophic lateral sclerosis by diffusion tensor imaging: Power calculations for group studies |
| title_sort | longitudinal monitoring of amyotrophic lateral sclerosis by diffusion tensor imaging power calculations for group studies |
| topic | Amyotrophic Lateral Sclerosis Diffusion Tensor Imaging longitudinal design statistical power study optimization |
| url | https://www.frontiersin.org/articles/10.3389/fnins.2022.929151/full |
| work_keys_str_mv | AT annabehler longitudinalmonitoringofamyotrophiclateralsclerosisbydiffusiontensorimagingpowercalculationsforgroupstudies AT dorotheelule longitudinalmonitoringofamyotrophiclateralsclerosisbydiffusiontensorimagingpowercalculationsforgroupstudies AT albertcludolph longitudinalmonitoringofamyotrophiclateralsclerosisbydiffusiontensorimagingpowercalculationsforgroupstudies AT albertcludolph longitudinalmonitoringofamyotrophiclateralsclerosisbydiffusiontensorimagingpowercalculationsforgroupstudies AT jankassubek longitudinalmonitoringofamyotrophiclateralsclerosisbydiffusiontensorimagingpowercalculationsforgroupstudies AT jankassubek longitudinalmonitoringofamyotrophiclateralsclerosisbydiffusiontensorimagingpowercalculationsforgroupstudies AT hanspetermuller longitudinalmonitoringofamyotrophiclateralsclerosisbydiffusiontensorimagingpowercalculationsforgroupstudies |