Sample size estimation: Current practice and considerations for original investigations in MRI technical development studies

Hanspach, Jannis; Nagel, Armin M.; Hensel, Bernhard; Uder, Michael; Koros, Leon; Laun, Frederik Bernd

doi:10.1002/mrm.28550

Cited by 38 publications

(30 citation statements)

References 29 publications

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“…First, the number of participants included is rather small, considering that there can be interindividual differences in DOMS expression and there may be nonresponders; however, our sample size of 16 is larger than the median sample size of current methodological MR studies. 41 Notably, we performed a high-resolution MRI at follow-up, which confirmed the presence of DOMS as intramuscular edema in every participant.…”

Section: Discussionmentioning

confidence: 63%

Effect of compression garments on muscle perfusion in delayed‐onset muscle soreness: A quantitative analysis using intravoxel incoherent motion MR perfusion imaging

et al. 2021

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The aim of this prospective cohort study was to evaluate the effect of compression garments under resting conditions and after the induction of delayed-onset muscle soreness (DOMS) by MR perfusion imaging using intravoxel incoherent motion (IVIM). Magnetic resonance imaging of both lower legs of 16 volunteers was performed before and after standardized eccentric exercises that induced DOMS. A compression garment (21-22 mmHg) was worn during and for 6 h after exercise on one randomly selected leg. IVIM MR imaging, represented as total muscle perfusion D*f, perfusion fraction f and tissue diffusivity D, were compared between baseline and directly, 30 min, 6 h and 48 h after exhausting exercise with and without compression. Creatine kinase levels and T2-weighted images were acquired at baseline and after 48 h. DOMS was induced in the medial head of the gastrocnemius muscle (MGM) in all volunteers. Compression garments did not show any significant effect on IVIM perfusion parameters at any time point in the MGM or the tibialis anterior muscle (p > 0.05). Microvascular perfusion in the MGM increased significantly in both the compressed and noncompressed leg between baseline measurements and those taken directly after and 30 min after the exercise: the relative median f increased by 31.5% and 24.7% in the compressed and noncompressed leg, respectively, directly after the exercise compared with the baseline value. No significant change in tissue perfusion occurred 48 h after the induction of DOMS compared with baseline. It was concluded that compression garments (21-22 mmHg) do not alter microvascular muscle perfusion at rest, nor do they have any significant Abbreviations used: C, compressed; CK, creatine kinase; DOMS, delayed-onset muscle soreness; EIMD, exercise-induced muscle damage; IFCC, International Federation of Clinical Chemistry and Laboratory Medicine; IVIM, intravoxel incoherent motion; MGM, medial head of the gastrocnemius muscle; NC, noncompressed; NEX, number of excitations; ROI, region of interest; SPAIR, spectral attenuated inversion recovery; TA, tibialis anterior muscle; TE, echo time; TIRM, turbo inversion recovery magnitude; TR, repetition time.

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Section: Discussionmentioning

confidence: 63%

Effect of compression garments on muscle perfusion in delayed‐onset muscle soreness: A quantitative analysis using intravoxel incoherent motion MR perfusion imaging

et al. 2021

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“…All of these vFA-EPTI protocols were able to produce high quality whole brain MWF maps, with clear white matter bundles, while achieving significant scan time reduction and/or increased spatial resolution. Only a limited number of subjects have been scanned in this preliminary study to evaluate the performance of the method, and more scans and repeatability tests ( Hanspach et al, 2021 ) will need to be conducted for further validation.…”

Section: Discussionmentioning

confidence: 99%

Variable flip angle echo planar time-resolved imaging (vFA-EPTI) for fast high-resolution gradient echo myelin water imaging

et al. 2021

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Myelin water imaging techniques based on multi-compartment relaxometry have been developed as an important tool to measure myelin concentration in vivo, but are limited by the long scan time of multi-contrast multi-echo acquisition. In this work, a fast imaging technique, termed variable flip angle Echo Planar Time-Resolved Imaging (vFA-EPTI), is developed to acquire multi-echo and multi-flip-angle gradient-echo data with significantly reduced acquisition time, providing rich information for multi-compartment analysis of gradient-echo myelin water imaging (GRE-MWI). The proposed vFA-EPTI method achieved 26 folds acceleration with good accuracy by utilizing an efficient continuous readout, optimized spatiotemporal encoding across echoes and flip angles, as well as a joint subspace reconstruction. An approach to estimate off-resonance field changes between different flip-angle acquisitions was also developed to ensure high-quality joint reconstruction across flip angles. The accuracy of myelin water fraction (MWF) estimate under high acceleration was first validated by a retrospective undersampling experiment using a lengthy fully-sampled data as reference. Prospective experiments were then performed where whole-brain MWF and multi-compartment quantitative maps were obtained in 5 min at 1.5 mm isotropic resolution and 24 min at 1 mm isotropic resolution at 3T. Additionally, ultra-high resolution data at 600 μm isotropic resolution were acquired at 7T, which show detailed structures within the cortex such as the line of Gennari, demonstrating the ability of the proposed method for submillimeter GRE-MWI that can be used to study cortical myeloarchitecture in vivo .

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“…Our work successfully demonstrates the feasibility of the presented motion-correction approach on a typical subject group size for current technical development MR studies. 43 Because the signal intensities were normalized to vitreous humor, relative deviations of the normalized signal intensity could be derived that should correspond to relative concentration deviations. However, for conclusions about the actual improvement in quantitative accuracy in future clinical 23 Na MRI studies, which will also depend on the characteristics of the examined pathology, quantitative measurements including crucial postprocessing steps for concentration determination such as correction of the coil sensitivity 44 and partial volume correction 12 are required.…”

Section: Discussionmentioning

confidence: 99%

Motion‐corrected ²³Na MRI of the human brain using interleaved ¹H 3D navigator images

Wilferth

Müller

Gast

et al. 2022

Magnetic Resonance in Med

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To evaluate the feasibility of motion correction for sodium ( 23 Na) MRI based on interleaved acquired 3D proton ( 1 H) navigator images.Methods: A 3D radial density-adapted sequence for interleaved 23 Na/ 1 H MRI was implemented on a 7 Tesla whole-body MRI system. The 1 H data obtained during the 23 Na acquisition were used to reconstruct 140 navigator image volumes with a nominal spatial resolution of (2.5 mm) 3 and a temporal resolution of 6 s. The motion information received from co-registration was then used to correct the 23 Na image dataset, which also had a nominal spatial resolution of (2.5 mm) 3 . The approach was evaluated on six healthy volunteers, whose motion during the scans had different intensities and characteristics.Results: Interleaved acquisition of two nuclei did not show any relevant influence on image quality (SNR of 13.0 for interleaved versus 13.2 for standard 23 Na MRI and 176.4 for interleaved versus 178.0 for standard 1 H MRI). The applied motion correction increased the consistency between two consecutive scans for all examined volunteers and improved the image quality for all kinds of motion. The SD of the differences ranged between 2.30% and 6.96% for the uncorrected and between 2.13% and 2.67% for the corrected images. Conclusion:The feasibility of interleaved acquired 1 H navigator images to be used for retrospective motion correction of 23 Na images was successfully demonstrated. The approach neither affected the 23 Na image quality nor elongated the scan time and can therefore be an important tool to improve the accuracy of quantitative 23 Na MRI.

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Sample size estimation: Current practice and considerations for original investigations in MRI technical development studies

Abstract: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Cited by 38 publications

References 29 publications

Effect of compression garments on muscle perfusion in delayed‐onset muscle soreness: A quantitative analysis using intravoxel incoherent motion MR perfusion imaging

Effect of compression garments on muscle perfusion in delayed‐onset muscle soreness: A quantitative analysis using intravoxel incoherent motion MR perfusion imaging

Variable flip angle echo planar time-resolved imaging (vFA-EPTI) for fast high-resolution gradient echo myelin water imaging

Motion‐corrected ²³Na MRI of the human brain using interleaved ¹H 3D navigator images

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Sample size estimation: Current practice and considerations for original investigations in MRI technical development studies

Abstract: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Cited by 38 publications

References 29 publications

Effect of compression garments on muscle perfusion in delayed‐onset muscle soreness: A quantitative analysis using intravoxel incoherent motion MR perfusion imaging

Effect of compression garments on muscle perfusion in delayed‐onset muscle soreness: A quantitative analysis using intravoxel incoherent motion MR perfusion imaging

Variable flip angle echo planar time-resolved imaging (vFA-EPTI) for fast high-resolution gradient echo myelin water imaging

Motion‐corrected 23Na MRI of the human brain using interleaved 1H 3D navigator images

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Motion‐corrected ²³Na MRI of the human brain using interleaved ¹H 3D navigator images