A method for correcting breathing‐induced field fluctuations in T2*‐weighted spinal cord imaging using a respiratory trace
<p><strong>Purpose</strong><br/> Spinal cord MRI at ultrahigh field is hampered by time‐varying magnetic fields associated with the breathing cycle, giving rise to ghosting artifacts in multi‐shot acquisitions. Here, we suggest a correction approach based on linking the signa...
| Main Authors: | , , , , |
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| Format: | Journal article |
| Language: | English |
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Wiley
2019
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| _version_ | 1797060030661394432 |
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| author | Vannesjo, J Clare, S Kasper, L Tracey, I Miller, K |
| author_facet | Vannesjo, J Clare, S Kasper, L Tracey, I Miller, K |
| author_sort | Vannesjo, J |
| collection | OXFORD |
| description | <p><strong>Purpose</strong><br/> Spinal cord MRI at ultrahigh field is hampered by time‐varying magnetic fields associated with the breathing cycle, giving rise to ghosting artifacts in multi‐shot acquisitions. Here, we suggest a correction approach based on linking the signal from a respiratory bellows to field changes inside the spinal cord. The information is used to correct the data at the image reconstruction level.</p><br/> <p><strong>Methods</strong><br/> The correction was demonstrated in the context of multi‐shot T2*‐weighted imaging of the cervical spinal cord at 7T. A respiratory trace was acquired during a high‐resolution multi‐echo gradient‐echo sequence, used for structural imaging and quantitative T2* mapping, and a multi‐shot EPI time series, as would be suitable for fMRI. The coupling between the trace and the breathing‐induced fields was determined by a short calibration scan in each individual. Images were reconstructed with and without trace‐based correction.</p><br/> <p><strong>Results</strong><br/> In the multi‐echo acquisition, breathing‐induced fields caused severe ghosting in images with long TE, which led to a systematic underestimation of T2* in the spinal cord. The trace‐based correction reduced the ghosting and increased the estimated T2* values. Breathing‐related ghosting was also observed in the multi‐shot EPI images. The correction largely removed the ghosting, thereby improving the temporal signal‐to‐noise ratio of the time series.</p><br/> <p><strong>Conclusions</strong><br/> Trace‐based retrospective correction of breathing‐induced field variations can reduce ghosting and improve quantitative metrics in multi‐shot structural and functional T2*‐weighted imaging of the spinal cord. The method is straightforward to implement and does not rely on sequence modifications or additional hardware beyond a respiratory bellows.</p> |
| first_indexed | 2024-03-06T20:12:01Z |
| format | Journal article |
| id | oxford-uuid:2ae5c56f-f6d9-4287-9e7d-105ed8f4a775 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T20:12:01Z |
| publishDate | 2019 |
| publisher | Wiley |
| record_format | dspace |
| spelling | oxford-uuid:2ae5c56f-f6d9-4287-9e7d-105ed8f4a7752022-03-26T12:27:46ZA method for correcting breathing‐induced field fluctuations in T2*‐weighted spinal cord imaging using a respiratory traceJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:2ae5c56f-f6d9-4287-9e7d-105ed8f4a775EnglishSymplectic Elements at OxfordWiley2019Vannesjo, JClare, SKasper, LTracey, IMiller, K<p><strong>Purpose</strong><br/> Spinal cord MRI at ultrahigh field is hampered by time‐varying magnetic fields associated with the breathing cycle, giving rise to ghosting artifacts in multi‐shot acquisitions. Here, we suggest a correction approach based on linking the signal from a respiratory bellows to field changes inside the spinal cord. The information is used to correct the data at the image reconstruction level.</p><br/> <p><strong>Methods</strong><br/> The correction was demonstrated in the context of multi‐shot T2*‐weighted imaging of the cervical spinal cord at 7T. A respiratory trace was acquired during a high‐resolution multi‐echo gradient‐echo sequence, used for structural imaging and quantitative T2* mapping, and a multi‐shot EPI time series, as would be suitable for fMRI. The coupling between the trace and the breathing‐induced fields was determined by a short calibration scan in each individual. Images were reconstructed with and without trace‐based correction.</p><br/> <p><strong>Results</strong><br/> In the multi‐echo acquisition, breathing‐induced fields caused severe ghosting in images with long TE, which led to a systematic underestimation of T2* in the spinal cord. The trace‐based correction reduced the ghosting and increased the estimated T2* values. Breathing‐related ghosting was also observed in the multi‐shot EPI images. The correction largely removed the ghosting, thereby improving the temporal signal‐to‐noise ratio of the time series.</p><br/> <p><strong>Conclusions</strong><br/> Trace‐based retrospective correction of breathing‐induced field variations can reduce ghosting and improve quantitative metrics in multi‐shot structural and functional T2*‐weighted imaging of the spinal cord. The method is straightforward to implement and does not rely on sequence modifications or additional hardware beyond a respiratory bellows.</p> |
| spellingShingle | Vannesjo, J Clare, S Kasper, L Tracey, I Miller, K A method for correcting breathing‐induced field fluctuations in T2*‐weighted spinal cord imaging using a respiratory trace |
| title | A method for correcting breathing‐induced field fluctuations in T2*‐weighted spinal cord imaging using a respiratory trace |
| title_full | A method for correcting breathing‐induced field fluctuations in T2*‐weighted spinal cord imaging using a respiratory trace |
| title_fullStr | A method for correcting breathing‐induced field fluctuations in T2*‐weighted spinal cord imaging using a respiratory trace |
| title_full_unstemmed | A method for correcting breathing‐induced field fluctuations in T2*‐weighted spinal cord imaging using a respiratory trace |
| title_short | A method for correcting breathing‐induced field fluctuations in T2*‐weighted spinal cord imaging using a respiratory trace |
| title_sort | method for correcting breathing induced field fluctuations in t2 weighted spinal cord imaging using a respiratory trace |
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