Simultane ²⁰¹ TI/^99mTc Seven-Pinhole Tomographie bei akutem Myokardinfarkt^[*]

Combined infarction scintigraphy with ²⁰¹TI-chloride and ^99mTc-pyrophosphate (PPi) by simultaneous seven-pinhole tomography was investigated with a phantom as well as in patients. No artificial defects occurred when the collimator was centered correctly in axial position, but a very high standard of image uniformity and linearity of the gamma camera was required. Artefacts by overlying activity from the skeleton or cardiac blood pool were not observed. All 11 controls showed normal results. Despite a poor depth resolution due to limitations of the system even small areas of partially damaged myocardium could be recognized and correlated three-dimensionally. Of 24 patients with proven myocardial infarction, in 16 both a positive (^99mTc-PPi) and a negative (²⁰¹Tl) image was obtained in congruence with the necrosis. 8 patients (33%) showed discordant results providing however additional information on the nature and extent of the necrosis. 4 out of 6 non-transmural infarctions seen by tomography had been suspected clinically.

Zusammenfassung

Die kombinierte Infarktszintigraphie mit ²⁰¹T1-Chlorid und ^99mTc-Pyrophosphat (PPi) mittels simultaner Seven-Pinhole-Tomographie wurde sowohl am Phantom als auch bei Patienten erprobt. Bei korrekter axialer Einstellung der Gammakamera traten keine artefiziellen Speicherdefekte auf; allerdings wurden sehr hohe Anforderungen an die Bildfeldhomogenität und -linearität der Gammakamera gestellt. Artefakte durch Aktivitätsüberlagerung von seiten des Skeletts oder des Herzbinnenraumes wurden ebenfalls nicht beobachtet, alle 11 Kontrollpatienten wiesen einen unauffälligen Befund auf. Trotz der systemeigenen geringen Tiefenauflösung konnten auch kleine Teilschädigungen des Myokards erkannt und räumlich zugeordnet werden. Von 24 Patienten mit nachgewiesenem Infarkt konnte dieser bei 16 Patienten deckungsgleich sowohl positiv (^99mTcPPi) als auch negativ (²⁰¹T1) dargestellt werden. 8 Patienten (33%) zeigten diskordante Befunde, die zusätzliche Informationen über Art und Ausmaß der Schädigung lieferten. Von 6 verifizierten intramuralen Infarkten waren 4 klinisch vermutet.

^* Herrn Prof. Dr. W. Wenz zum 60. Geburtstag

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