{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T09:40:39Z","timestamp":1785404439574,"version":"3.56.0"},"reference-count":6,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2026,6,12]],"date-time":"2026-06-12T00:00:00Z","timestamp":1781222400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001691","name":"Japan Society for the Promotion of Science","doi-asserted-by":"publisher","award":["24K13543"],"award-info":[{"award-number":["24K13543"]}],"id":[{"id":"10.13039\/501100001691","id-type":"DOI","asserted-by":"publisher"}]},{"award":["24K13543"],"award-info":[{"award-number":["24K13543"]}],"id":[{"id":"https:\/\/ror.org\/00hhkn466","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>99mTc-pyrophosphate (PYP) scintigraphy is widely used for the noninvasive evaluation of transthyretin cardiac amyloidosis. Although interpretation primarily focuses on myocardial uptake, confirmation of appropriate systemic radiotracer biodistribution is essential. We report a case in which an examination presumed to be 99mTc-PYP scintigraphy demonstrated free 99mTc-pertechnetate-like biodistribution. A 75-year-old woman with chronic kidney disease and conduction disturbance underwent 99mTc-PYP scintigraphy for suspected cardiac amyloidosis. The initial study, recorded as the administration of 740 MBq 99mTc-PYP, was imaged 3 h after injection. Planar imaging showed mild apparent activity over the cardiac region; however, SPECT\/CT demonstrated no definite myocardial uptake. Instead, intense uptake was observed in the stomach and thyroid gland, with complete absence of skeletal activity. This distribution was inconsistent with correctly administered 99mTc-PYP and suggested free 99mTc-pertechnetate biodistribution, likely due to radiopharmaceutical preparation or administration error. A repeat 99mTc-PYP scan 1.5 months later showed expected skeletal uptake without gastric or thyroid activity and again demonstrated no myocardial uptake. The study was interpreted as negative for cardiac amyloidosis. Gastric and thyroid uptake with absent skeletal activity on presumed 99mTc-PYP scintigraphy should be considered nondiagnostic rather than negative.<\/jats:p>","DOI":"10.3390\/diagnostics16121829","type":"journal-article","created":{"date-parts":[[2026,6,15]],"date-time":"2026-06-15T00:44:58Z","timestamp":1781484298000},"page":"1829","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A Nondiagnostic 99mTc-PYP Scan with Absent Skeletal Uptake"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1014-2833","authenticated-orcid":false,"given":"Hiroyuki","family":"Tokue","sequence":"first","affiliation":[{"name":"Department of Diagnostic and Interventional Radiology, Gunma University Hospital, 3-39-22 Showa-Machi, Maebashi 371-8511, Gunma, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Azusa","family":"Tokue","sequence":"additional","affiliation":[{"name":"Department of Diagnostic and Interventional Radiology, Gunma University Hospital, 3-39-22 Showa-Machi, Maebashi 371-8511, Gunma, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yoshito","family":"Tsushima","sequence":"additional","affiliation":[{"name":"Department of Diagnostic and Interventional Radiology, Gunma University Hospital, 3-39-22 Showa-Machi, Maebashi 371-8511, Gunma, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,12]]},"reference":[{"key":"ref_1","unstructured":"American Society of Nuclear Cardiology (2026, May 07). ASNC Cardiac Amyloidosis Practice Points Update: 99mTechnetium-Pyrophosphate Imaging for Transthyretin Cardiac Amyloidosis. Revised 2022. Available online: https:\/\/www.asnc.org\/wp-content\/uploads\/2024\/05\/19110-2021-ASNC-Amyloid-Practice-Points-PYP-MAY19-2022-1.pdf."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2065","DOI":"10.1007\/s12350-019-01760-6","article-title":"ASNC\/AHA\/ASE\/EANM\/HFSA\/ISA\/SCMR\/SNMMI expert consensus recommendations for multimodality imaging in cardiac amyloidosis: Part 1 of 2-evidence base and standardized methods of imaging","volume":"26","author":"Dorbala","year":"2019","journal-title":"J. Nucl. Cardiol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"519","DOI":"10.1089\/thy.2009.0213","article-title":"Distribution and dynamics of (99m)Tc-pertechnetate uptake in the thyroid and other organs assessed by single-photon emission computed tomography in living mice","volume":"20","author":"Franken","year":"2010","journal-title":"Thyroid"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"791","DOI":"10.2967\/jnumed.116.178509","article-title":"Clinical Trial with Sodium 99mTc-Pertechnetate Produced by a Medium-Energy Cyclotron: Biodistribution and Safety Assessment in Patients with Abnormal Thyroid Function","volume":"58","author":"Selivanova","year":"2017","journal-title":"J. Nucl. Med."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"3542","DOI":"10.1007\/s12350-021-02794-5","article-title":"Unanticipated findings and their implications","volume":"29","author":"Zuckier","year":"2022","journal-title":"J. Nucl. Cardiol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"3539","DOI":"10.1007\/s12350-021-02762-z","article-title":"Exclusive gastric uptake on 99m-Technetium pyrophosphate scanning","volume":"29","author":"Hussain","year":"2022","journal-title":"J. Nucl. Cardiol."}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/12\/1829\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,19]],"date-time":"2026-06-19T04:11:14Z","timestamp":1781842274000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/12\/1829"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,12]]},"references-count":6,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2026,6]]}},"alternative-id":["diagnostics16121829"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics16121829","relation":{},"ISSN":["2075-4418"],"issn-type":[{"value":"2075-4418","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6,12]]}}}