Sensitivity analyses of probabilistic and deterministic DTI tractography methodologies for studying arm muscle architecture

• Published in: Magnetic resonance in medicine 2024-02, Vol.91 (2), p.497-512
• Main Authors: Joshi, Divya, Sohn, M. Hongchul, Dewald, Julius P. A., Murray, Wendy M., Ingo, Carson
• Format: Article
• Language: English
• Subjects: Algorithms; Arm; Best practice; Cadavers; deterministic; diffusion tensor imaging; Diffusion Tensor Imaging - methods; Geometry; Humans; Image acquisition; In vivo methods and tests; muscle architecture; Muscle, Skeletal - diagnostic imaging; Muscles; Nerve Tissue; Polynomials; probabilistic; Probabilistic methods; Sensitivity analysis; Skeletal muscle; tractography; Ultrasonography
• ISSN: 0740-3194; 1522-2594
• DOI: 10.1002/mrm.29862

Purpose To determine the sensitivity profiles of probabilistic and deterministic DTI tractography methods in estimating geometric properties in arm muscle anatomy. Methods Spin‐echo diffusion‐weighted MR images were acquired in the dominant arm of 10 participants. Both deterministic and probabilistic tractography were performed in two different muscle architectures of the parallel‐structured biceps brachii (and the pennate‐structured flexor carpi ulnaris. Muscle fascicle geometry estimates and number of fascicles were evaluated with respect to tractography turning angle, polynomial fitting order, and SNR. The DTI tractography estimated fascicle lengths were compared with measurements obtained from conventional cadaveric dissection and ultrasound modalities. Results The probabilistic method generally estimated fascicle lengths closer to ranges reported by conventional methods than the deterministic method, most evident in the biceps brachii (p > 0.05), consisting of longer, arc‐like fascicles. For both methods, a wide turning angle (50º–90°) generated fascicle lengths that were in close agreement with conventional methods, most evident in the flexor carpi ulnaris (p > 0.05), consisting of shorter, feather‐like fascicles. The probabilistic approach produced at least two times more fascicles than the deterministic approach. For both approaches, second‐order fitting yielded about double the complete tracts as third‐order fitting. In both muscles, as SNR decreased, deterministic tractography produced less fascicles but consistent geometry (p > 0.05), whereas probabilistic tractography produced a consistent number but altered geometry of fascicles (p