eprintid: 10089215 rev_number: 30 eprint_status: archive userid: 608 dir: disk0/10/08/92/15 datestamp: 2020-01-09 13:50:40 lastmod: 2021-12-09 00:02:03 status_changed: 2020-01-09 13:50:40 type: article metadata_visibility: show creators_name: Kowalik, GT creators_name: Knight, D creators_name: Steeden, JA creators_name: Muthurangu, V title: Perturbed spiral real-time phase-contrast MR with compressive sensing reconstruction for assessment of flow in children ispublished: inpress subjects: GOSH subjects: RFH divisions: UCL divisions: B02 divisions: D14 divisions: GA1 keywords: compressive sensing, PCMR, real-time note: © 2019 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/). abstract: PURPOSE: we implemented a golden‐angle spiral phase contrast sequence. A commonly used uniform density spiral and a new ‘perturbed’ spiral that produces more incoherent aliases were assessed. The aim was to ascertain whether greater incoherence enabled more accurate Compressive Sensing reconstruction and superior measurement of flow and velocity. METHODS: A range of ‘perturbed’ spiral trajectories based on a uniform spiral trajectory were formulated. The trajectory that produced the most noise‐like aliases was selected for further testing. For in‐silico and in‐vivo experiments, data was reconstructed using total Variation L1 regularisation in the spatial and temporal domains. In‐silico, the reconstruction accuracy of the ‘perturbed’ golden spiral was compared to uniform density golden‐angle spiral. For the in‐vivo experiment, stroke volume and peak mean velocity were measured in 20 children using ‘perturbed’ and uniform density golden‐angle spiral sequences. These were compared to a reference standard gated Cartesian sequence. RESULTS: In‐silico, the perturbed spiral acquisition produced more accurate reconstructions with less temporal blurring (NRMSE ranging from 0.03 to 0.05) than the uniform density acquisition (NRMSE ranging from 0.06 to 0.12). This translated in more accurate results in‐vivo with no significant bias in the peak mean velocity (bias: −0.1, limits: −4.4 to 4.1 cm/s; P = 0.98) or stroke volume (bias: −1.8, limits: −9.4 to 5.8 ml, P = 0.19). CONCLUSION: We showed that a ‘perturbed’ golden‐angle spiral approach is better suited to Compressive Sensing reconstruction due to more incoherent aliases. This enabled accurate real‐time measurement of flow and peak velocity in children. date: 2019-11-08 date_type: published publisher: WILEY official_url: https://doi.org/10.1002/mrm.28065 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1716439 doi: 10.1002/mrm.28065 lyricists_name: Knight, Daniel lyricists_name: Kowalik, Grzegorz lyricists_name: Muthurangu, Vivek lyricists_name: Steeden, Jennifer lyricists_id: DSKNI50 lyricists_id: GKOWA82 lyricists_id: VMUTH99 lyricists_id: JAEDG41 actors_name: Kowalik, Grzegorz actors_id: GKOWA82 actors_role: owner full_text_status: public publication: Magnetic Resonance in Medicine pages: 15 issn: 1522-2594 citation: Kowalik, GT; Knight, D; Steeden, JA; Muthurangu, V; (2019) Perturbed spiral real-time phase-contrast MR with compressive sensing reconstruction for assessment of flow in children. Magnetic Resonance in Medicine 10.1002/mrm.28065 <https://doi.org/10.1002/mrm.28065>. (In press). Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10089215/3/Kowalik_Perturbed%20spiral%20real-time%20phase-contrast%20MR%20with%20compressive%20sensing%20reconstruction%20for%20assessment%20of%20flow%20in%20children_AOP.pdf