This electronic educational poster will first introduce the concept behind Compressed Sensing - a very powerful MR technique (that has just become commercially available in 2018) allowing for, amongst many different applications, acceleration of MR data acquisition beyond parallel imaging (SENSE, GRAPPA, ASSET). Then, the poster will show comparative clinical examples of application of Compressed Sensing onto commonly used cardiovascular MR sequences such as 1) cine balanced SSFP, both breath-hold and non-breath-hold examinations, 2) cine phase contrast in free-breathing, and 3) respiratory-navigated 3D Whole-Heart examination using T1-weighted fast gradient echo sequence with DIXON technique. In these clinical examples, Compressed Sensing, in addition to parallel imaging, can further accelerate the acquisition time to allow for less number of breath-holds for patients to complete a stack of cine images through the ventricles without sacrificing spatial or temporal resolution or signal-to-noise ratio. The acquisition time of free-breathing cine phase contrast can be reduced and yield accurate flow quantification. The increased speed of acquisition can be traded off to achieve higher spatial resolution in young patients who may not be able to achieve long breath-hold times otherwise needed when high spatial resolution is necessary. These clinical examples were accumulated since January 2017 with a Compressed Sensing software patch made available by the scientific research group of the MR vendor under research agreement and the clinical use was approved by Institutional Review Board. Read More

Meeting name: SPR 2019 Annual Meeting & Postgraduate Course , 2019

Authors: Chung Taylor, Doneva Mariya, Lu Quin, Hitt Dave, Tamir Jonathan

Keywords: Magnetic Resonance

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

Current musculoskeletal MR imagiing utilizes multiple imaging planes and multiple weightings of two-dimensional turbo spin echo (2D TSE) to precisely delineate and characterize intra-articular abnormalities. Three-dimensional (3D) TSE sequences are currently available on most MRI vendor platforms. High resolution isotropic 3D imaging of the small joints reduces partial volume artifacts and allows for the reconstruction in any orientation, thus eliminating the need to acquire additional scans of different orientations with identical tissue contrast. However, the typical trade off of achieving very high resolution (under 0.5mm isotropic) is long acquisition time. Scan time reduction can be achieved with parallel imaging at the expense of reducing the signal-to-noise ratio (SNR) and with increasing the echo train length at the expense of image blurring. The addition of compressed sensing (CS), a recently commercially available acceleration technique, allows for decrease in acquisition time without the significant loss of SNR experienced with identical acceleration factors achieved with parallel imaging alone. CS exploits (1) image data sparsity via application of a sparsity transform of the image data; (2) pseudo-random-type of k-space sampling; (3) non-linear iterative reconstruction. We utilized CS to decrease scan time (range 4:55 to 5:35 minutes) of 3D PD FS TSE sequences to obtain high resolution (voxel size 0.45 x 0.45 x 0.45) imaging of the fingers, toes, wrist and feet. In this educational exhibit, we will review the normal anatomy and pathology of small joints Read More

Meeting name: SPR 2019 Annual Meeting & Postgraduate Course , 2019

Authors: Padua Eric, Kammen Bamidele, Karakas S Pinar, Hitt Dave, Tai Chau, Pandya Nirav, Lu Quin, Chung Taylor

Keywords: musculoskeletal