Diffusion tensor imaging (DTI) depicts the anisotropic motion of water molecules limited by tissue microstructure. Images of tractography provide qualitative information about complex tissue architecture, so that diffusion metrics reflect physeal activity. DTI’s main clinical application is on brain white matter, but it can be used in any tissue in which there is organized tissue structure. Our research group has used tractography of the knee to study the structure of the physis and adjacent metaphysis and investigated the potential of DTI metrics as biomarkers predictive of skeletal growth. DTI parameters include tract count, tract length and tract volume and fractional anisotropy (FA). They can help distinguish between a normal and a dysfunctional physis, predict post-imaging growth and physeal closure, and possibly determine response to growth hormone treatment. We will demonstrate the techniques for data acquisition, preprocessing, and analysis, and the basis for interpretation, based on our experience of performing DTI in over 900 knees. Each step has its own challenges for the standardization and optimization of DTI of the physis. The goal of this poster is to showcase our experience with the establishment of an efficient DTI pipeline. We will: 1) Discuss the impact of variation of DTI acquisition parameters (e.g. Time to Echo (TE), number of directions, b-value, voxel size…); 2) Describe programs for distortion correction and denoising , as well as the required post-processing software programs; 3) Discuss approaches to standardize the acquisition in the different anatomic areas and cross vendors; 4) Discuss the normal change of tractography data and physeal DTI metrics with age, sex and specific knee physis. We will show how DTI changes due to physeal dysfunction in different pathologies, such as growth hormone deficiency, trauma, arthritis, metabolic disorders and chemotherapy and radiation therapy. Finally, we will show how DTI can be used to predict height gain and final height compared to conventional bone age-based methods and standard growth charts, which are inaccurate and not generalizable to the current child/adolescent population. Read More

Meeting name: SPR 2023 Annual Meeting & Postgraduate Course , 2023

Authors: Santos Laura, Jaramillo Diego, Raya José, Jambawalikar Sachin, Nguyen Jie, Mostoufi-moab Sogol

Keywords: magnetic resonance imaging, growth plate, diffusion tensor imaging

There is growing research in diffusion tensor imaging (DTI) for providing metrics and images of physeal structure and function, particularly in evaluating children with possible growth disorders. There is a need for a faster automated process to segment the diffusion data, however. We utilized a deep learning algorithm to automatically generate a region of interest (ROI) for use in fully automatic diffusion tensor tractography of cartilage columns in the distal femoral physis. Read More

Meeting name: SPR 2020 Annual Meeting & Postgraduate Course , 2020

Authors: Mutasa Simukayi, Liu Michael, Duong Phuong, Jambawalikar Sachin, Mostoufi-moab Sogol, Jaramillo Diego

Keywords: Deep learning, growth disorders, MRi

Diffusion tensor imaging (DTI) is a technique in which diffusion of water molecules is restricted by cellular membranes. In the physis and adjacent metaphysis, the physeal metaphyseal complex (PMC), the columns of cartilage and newly formed bone restrict the diffusion of water to primarily the longitudinal direction. DTI indirectly measures physeal activity by revealing tissue microarchitecture of the PMC and by measuring the Brownian motion of water along the columns of bone and cartilage, which can be imaged and quantified as tractography. Having conducted DTI-MRI on over 900 knees, our research group has established that DTI can distinguish between a normal and a dysfunctional physis. A physeal bar or partial physeal arrest is the consequence of injury to an open physis, resulting in a perpendicular bony bridge through the physis which can lead to limb shortening or angular deformity. This poster presents our initial experience in performing DTI on the growth plate in 7 patients (5 females, 2 males) with MR-confirmed physeal bars to characterize tractography patterns associated with bony bridges and compare the tracotgraphy and diffusion metrics of the injured versus the healthy contralateral physis. Read More

Meeting name: SPR 2024 Annual Meeting & Postgraduate Course , 2024

Authors: Santos Laura, Kammen Bamidele, Sabharwal Sanjeev, Kvist Ola, Hitt Dave, Jambawalikar Sachin, Jaramillo Diego

Keywords: diffusion tensor imaging, physeal bar, physeal injury