{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T13:45:19Z","timestamp":1792071919880,"version":"4.4.0"},"reference-count":18,"publisher":"Wiley","issue":"9","license":[{"start":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T00:00:00Z","timestamp":1788307200000},"content-version":"vor","delay-in-days":1,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,9,1]],"date-time":"2026-09-01T00:00:00Z","timestamp":1788220800000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"funder":[{"DOI":"10.13039\/100000738","name":"U.S. Department of Veterans Affairs","doi-asserted-by":"publisher","award":["I50CX002551"],"award-info":[{"award-number":["I50CX002551"]}],"id":[{"id":"10.13039\/100000738","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["aapm.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Medical Physics"],"published-print":{"date-parts":[[2026,9]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>X\u2010ray pulsatility index (XPI) quantifies cardiac\u2010synchronous attenuation changes as a surrogate for regional lung perfusion, but current implementations are limited by projectional overlap and the lack of reference values in healthy individuals.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Purpose<\/jats:title>\n                    <jats:p>To characterize regional XPI patterns and establish preliminary reference values in healthy participants using a novel multi\u2010angle fluoroscopic imaging system.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      Nineteen healthy participants underwent an 8\u00a0s breath\u2010hold during fluoroscopic imaging using 15 fps at four simultaneous projections (LPO, AP caudal, RPO, AP cranial) using a novel scanner. Frames were cropped to exclude initial x\u2010ray tube stabilization and bulk motion. Spectral analysis exploited the periodic signal attenuation in the lungs to create XPI maps, as previously described. To focus on the clinically important regions of lung perfusion, the peripheral 3\u00a0cm of lung was manually segmented and divided into upper, middle, and lower lung zones. XPI values from these regions were compared to evaluate laterality and cranial\u2013caudal differences using paired\n                      <jats:italic>t<\/jats:italic>\n                      \u2010tests corrected with the Benjamini\u2010Hochberg procedure to control the False Discovery Rate (FDR). Peripheral XPI contrast\u2010to\u2010noise (pCNR) was calculated in the AP caudal projection to quantify signal\u2010to\u2010background separation. Data were retrospectively resampled to assess the effect of reduced frame rate (7.5, 5 fps) and shorter acquisition time using multiple regression analysis. Radiation dose was estimated using phantom measurements and simulation.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      All participants performed the breath\u2010hold without difficulty. XPI maps demonstrated bilateral lung perfusion across all four views, enabling multi\u2010projection assessment of regional perfusion. No focal defects were observed; however, one participant demonstrated globally reduced XPI. Significant cranial\u2013caudal gradients in XPI were observed across projection angles, consistent with known gravity\u2010dependent physiology. Following FDR adjustment (\n                      <jats:italic>Q<\/jats:italic>\n                      \u00a0=\u00a00.05), the lower zones continued to demonstrate significantly higher values than the upper zones in 3 of 4 projections (all\n                      <jats:italic>q<\/jats:italic>\n                      \u00a0&lt;\u00a00.05). There were no significant laterality differences (\n                      <jats:italic>q<\/jats:italic>\n                      \u00a0&gt;\u00a00.05). XPI values remained stable across acquisition lengths and frame rates, indicating robustness of the metric. CNR increased with longer acquisitions and higher frame rates, reflecting reduced noise and improved signal reliability.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Multi\u2010angle XPI fluoroscopy enables non\u2010invasive regional lung perfusion assessment with low radiation exposure and provides preliminary reference values for future clinical investigation.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/mp.70666","type":"journal-article","created":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T07:54:56Z","timestamp":1788335696000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Multi\u2010angle fluoroscopic lung perfusion imaging using x\u2010ray pulsatility index: A pilot study in healthy subjects"],"prefix":"10.1002","volume":"53","author":[{"given":"Matthew R.","family":"Smith","sequence":"first","affiliation":[{"name":"Department of Radiology University of Wisconsin School of Medicine and Public Health  Madison Wisconsin USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bradley W.","family":"Richmond","sequence":"additional","affiliation":[{"name":"Department of Veterans Affairs Medical Center  Nashville Tennessee USA"},{"name":"Division of Allergy, Pulmonary, and Critical Care Medicine Vanderbilt University School of Medicine  Nashville Tennessee USA"},{"name":"Department of Cell and Developmental Biology Vanderbilt University  Nashville Tennessee USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Savannah","family":"Gregory","sequence":"additional","affiliation":[{"name":"Department of Medicine, Division of Allergy, Pulmonary, and Critical Care Medicine Vanderbilt Health  Nashville Tennessee USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maggie","family":"Cartwright","sequence":"additional","affiliation":[{"name":"Vanderbilt University Institute of Imaging Science  Nashville Tennessee USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andreas","family":"Fouras","sequence":"additional","affiliation":[{"name":"4D Medical  Melbourne Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Greg T.","family":"Mogel","sequence":"additional","affiliation":[{"name":"4D Medical  Melbourne Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Charles R.","family":"Hatt","sequence":"additional","affiliation":[{"name":"4D Medical  Melbourne Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gary T.","family":"Smith","sequence":"additional","affiliation":[{"name":"Department of Radiology Vanderbilt Health  Nashville Tennessee USA"},{"name":"Vanderbilt University Institute for Imaging Science Vanderbilt Health  Nashville Tennessee USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jared V.","family":"Grice","sequence":"additional","affiliation":[{"name":"Department of Radiology Vanderbilt Health  Nashville Tennessee USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,9,2]]},"reference":[{"key":"e_1_2_8_2_1","doi-asserted-by":"publisher","DOI":"10.1097\/01.HP.0000326336.40775.94"},{"key":"e_1_2_8_3_1","doi-asserted-by":"publisher","DOI":"10.21037\/QIMS\u201020\u20101217"},{"key":"e_1_2_8_4_1","doi-asserted-by":"publisher","DOI":"10.1002\/mp.14407"},{"key":"e_1_2_8_5_1","doi-asserted-by":"publisher","DOI":"10.1253\/CIRCJ.CJ\u201020\u20100835"},{"key":"e_1_2_8_6_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.acra.2018.12.012"},{"key":"e_1_2_8_7_1","doi-asserted-by":"publisher","DOI":"10.1007\/s12194\u2010009\u20100074\u20101"},{"key":"e_1_2_8_8_1","doi-asserted-by":"publisher","DOI":"10.1007\/S10554\u2010024\u201003121\u2010Y"},{"key":"e_1_2_8_9_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140\u20106736(19)30427\u20101"},{"key":"e_1_2_8_10_1","doi-asserted-by":"publisher","DOI":"10.1093\/bjr\/tqaf165"},{"key":"e_1_2_8_11_1","doi-asserted-by":"publisher","DOI":"10.1016\/J.ACRA.2025.11.016"},{"key":"e_1_2_8_12_1","doi-asserted-by":"publisher","DOI":"10.1002\/MP.16953"},{"key":"e_1_2_8_13_1","unstructured":"SmithM GriceJ O'LearyJ SmithG Lung perfusion imaging without contrast: clinical feasibility following acute blood flow occlusion. 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