Anoosha Pai S

All Publications

• Estimation and assessment of sagittal spinal curvature and thoracic muscle morphometry in different postures PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART H-JOURNAL OF ENGINEERING IN MEDICINE Pai, A. S., Zhang, H., Ashjaee, N., Wilson, D. R., Brown, S. M., Fels, S., Street, J., Oxland, T. R. 2021; 235 (8): 883-896

  Abstract

  Spine models are typically developed from supine clinical imaging data, and hence clearly do not fully reflect postures that replicate subjects' clinical symptoms. Our objectives were to develop a method to: (i) estimate the subject-specific sagittal curvature of the whole spine in different postures from limited imaging data, (ii) obtain muscle lines-of-action in different postures and analyze the effect of posture on muscle fascicle length, and (iii) correct for cosine between the magnetic resonance imaging (MRI) scan plane and dominant fiber line-of-action for muscle parameters (cross-sectional area (CSA) and position). The thoracic spines of six healthy volunteers were scanned in four postures (supine, standing, flexion, and sitting) in an upright MRI. Geometry of the sagittal spine was approximated with a circular spline. A pipeline was developed to estimate spine geometry in different postures and was validated. The lines-of-action for two muscles, erector spinae (ES) and transversospinalis (TS) were obtained for every posture and hence muscle fascicle lengths were computed. A correction factor based on published literature was then computed and applied to the muscle parameters. The maximum registration error between the estimated spine geometry and MRI data was small (average RMSE∼1.2%). The muscle fascicle length increased (up to 20%) in flexion when compared to erect postures. The correction factor reduced muscle parameters (∼5% for ES and ∼25% for TS) when compared to raw MRI data. The proposed pipeline is a preliminary step in subject-specific modeling. Direction cosines of muscles could be used while improving the inputs of spine models.

  View details for DOI 10.1177/09544119211014668

  View details for Web of Science ID 000652308400001

  View details for PubMedID 33977818

• Preliminary investigation of spinal level and postural effects on thoracic muscle morphology with upright open MRI JOR SPINE Pai, S., Zhang, H., Street, J., Wilson, D. R., Brown, S. M., Oxland, T. R. 2021; 4 (1)

  View details for DOI 10.1002/jsp2.1139

  View details for Web of Science ID 000615955000001

• A Tunable Variable-Torque Compliant Hinge Using Open-Section Shells JOURNAL OF MECHANISMS AND ROBOTICS-TRANSACTIONS OF THE ASME Hampali, S., Pai, A. S., Ananthasuresh, G. K. 2020; 12 (6)

  View details for DOI 10.1115/1.4047440

  View details for Web of Science ID 000591902300001

• Quantitative identification and segmentation repeatability of thoracic spinal muscle morphology JOR SPINE Pai, A. S., Zhang, H., Shewchuk, J. R., Al Omran, B., Street, J., Wilson, D., Doroudi, M., Brown, S. M., Oxland, T. R. 2020; 3 (3): e1103

  Abstract

  MRI derived spinal-muscle morphology measurements have potential diagnostic, prognostic, and therapeutic applications in spinal health. Muscle morphology in the thoracic spine is an important determinant of kyphosis severity in older adults. However, the literature on quantification of spinal muscles to date has been limited to cervical and lumbar regions. Hence, we aim to propose a method to quantitatively identify regions of interest of thoracic spinal muscle in axial MR images and investigate the repeatability of their measurements.Middle (T4-T5) and lower (T8-T9) thoracic levels of six healthy volunteers (age 26 ± 6 years) were imaged in an upright open scanner (0.5T MROpen, Paramed, Genoa, Italy). A descriptive methodology for defining the regions of interest of trapezius, erector spinae, and transversospinalis in axial MR images was developed. The guidelines for segmentation are laid out based on the points of origin and insertion, probable size, shape, and the position of the muscle groups relative to other recognizable anatomical landmarks as seen from typical axial MR images. 2D parameters such as muscle cross-sectional area (CSA) and muscle position (radius and angle) with respect to the vertebral body centroid were computed and 3D muscle geometries were generated. Intra and inter-rater segmentation repeatability was assessed with intraclass correlation coefficient (ICC (3,1)) for 2D parameters and with dice coefficient (DC) for 3D parameters.Intra and inter-rater repeatability for 2D and 3D parameters for all muscles was generally good/excellent (average ICC (3,1) = 0.9 with ranges of 0.56-0.98; average DC = 0.92 with ranges from 0.85-0.95).The guidelines proposed are important for reliable MRI-based measurements and allow meaningful comparisons of muscle morphometry in the thoracic spine across different studies globally. Good segmentation repeatability suggests we can further investigate the effect of posture and spinal curvature on muscle morphology in the thoracic spine.

  View details for DOI 10.1002/jsp2.1103

  View details for Web of Science ID 000547004500001

  View details for PubMedID 33015576

  View details for PubMedCentralID PMC7524235

• An Open-Section Shell Designed for Customized Bending and Twisting to Ease Sitting and Rising in a Chair Hampali, S., Anoosha, P. S., Ananthasuresh, G. K., Badodkar, D. N., Dwarakanath, T. A. SPRINGER-VERLAG BERLIN. 2019: 427-439

  View details for DOI 10.1007/978-981-10-8597-0_36

  View details for Web of Science ID 000460561900036