{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T16:32:46Z","timestamp":1790008366024,"version":"4.0.1"},"reference-count":17,"publisher":"Wiley","issue":"6","license":[{"start":{"date-parts":[[2015,7,20]],"date-time":"2015-07-20T00:00:00Z","timestamp":1437350400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"funder":[{"DOI":"10.13039\/100000065","name":"National Institute of Neurological Disorders and Stroke","doi-asserted-by":"crossref","id":[{"id":"10.13039\/100000065","id-type":"DOI","asserted-by":"crossref"}]},{"name":"National Institute of Mental Health, National Institute on Deafness and Other Communication Disorders at NIH"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Magnetic Resonance in Med"],"published-print":{"date-parts":[[2016,6]]},"abstract":"<jats:sec><jats:title>Purpose<\/jats:title><jats:p>To demonstrate that the temporal signal\u2010to\u2010noise ratio (SNR) of generalized autocalibrating partially parallel acquisitions (GRAPPA) accelerated echo planar imaging (EPI) can be enhanced and made more spatially uniform by using a fast low angle shot (FLASH) based calibration scan.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>EPI of a phantom and human brains were acquired at 3 Tesla without and with GRAPPA acceleration factor of 2. The GRAPPA accelerated data were reconstructed using calibration scans acquired with EPI and FLASH acquisition schemes. The increase in temporal signal fluctuation due to GRAPPA reconstruction was quantified and compared. Simulated <jats:italic>g<\/jats:italic>\u2010factor maps were also created for different calibration scans.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>GRAPPA accelerated phantom data exhibited areas with high <jats:italic>g<\/jats:italic> values when using the EPI based calibration for reconstruction. The <jats:italic>g<\/jats:italic>\u2010factor maps were uniform when using the FLASH calibration scan. <jats:italic>g<\/jats:italic> was greater than 1.1 in 74% of pixels in 64 \u00d7 64 data reconstructed with the EPI calibration compared with only 15% when using the FLASH calibration scan. Human data also showed abnormally high <jats:italic>g<\/jats:italic> regions when using the EPI calibration but not when using the FLASH calibration scan. Use of the FLASH calibration scan increased the whole brain temporal SNR by \u223c12% without affecting the image quality. Experimental observations were confirmed by simulations.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>A calibration scan based on a FLASH acquisition scheme can be used to improve the temporal SNR of GRAPPA accelerated EPI time series. Magn Reson Med 75:2362\u20132371, 2016. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.<\/jats:p><\/jats:sec>","DOI":"10.1002\/mrm.25846","type":"journal-article","created":{"date-parts":[[2015,7,20]],"date-time":"2015-07-20T12:49:12Z","timestamp":1437396552000},"page":"2362-2371","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":54,"title":["Improvement of temporal signal\u2010to\u2010noise ratio of GRAPPA accelerated echo planar imaging using a FLASH based calibration scan"],"prefix":"10.1002","volume":"75","author":[{"given":"S. Lalith","family":"Talagala","sequence":"first","affiliation":[{"name":"NIH MRI Research Facility National Institute of Neurological Disorders and Stroke, National Institutes of Health Bethesda Maryland USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joelle E.","family":"Sarlls","sequence":"additional","affiliation":[{"name":"NIH MRI Research Facility National Institute of Neurological Disorders and Stroke, National Institutes of Health Bethesda Maryland USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Siyuan","family":"Liu","sequence":"additional","affiliation":[{"name":"Language Section, Voice, Speech and Language Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health Bethesda Maryland USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Souheil J.","family":"Inati","sequence":"additional","affiliation":[{"name":"Functional MRI Facility National Institute of Mental Health, National Institutes of Health Bethesda Maryland USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2015,7,20]]},"reference":[{"key":"e_1_2_6_2_1","doi-asserted-by":"publisher","DOI":"10.1002\/mrm.1910380414"},{"key":"e_1_2_6_3_1","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1522-2594(199911)42:5<952::AID-MRM16>3.0.CO;2-S"},{"key":"e_1_2_6_4_1","doi-asserted-by":"publisher","DOI":"10.1002\/mrm.10171"},{"key":"e_1_2_6_5_1","doi-asserted-by":"publisher","DOI":"10.1002\/mrm.22066"},{"key":"e_1_2_6_6_1","doi-asserted-by":"publisher","DOI":"10.1002\/mrm.21728"},{"key":"e_1_2_6_7_1","doi-asserted-by":"publisher","DOI":"10.1002\/jmri.22891"},{"key":"e_1_2_6_8_1","unstructured":"TalagalaSL SarllsJE InatiSJ. 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