Whole-body imaging of oncologic patients using 16-channel PET-CT

Summary

Aim: This study evaluated a MDCT protocol for contrast-enhanced 16-channel PET-CT with regard to scan range and duration of a whole-body ¹⁸F-FDG PET-CT examination, the occurrence of contrast-material induced artefacts and quantitative assessment of CT attenuation. Patients, methods: 205 patients (51.9 ± 12.4 years) with different malignant tumours underwent whole-body PET-CT; the study protocol had been approved by the institutional review board. Contrast-enhanced MDCT (16 ˟ 1.5 mm; 120 ml Iomeprol 3 ml/s, 50 ml saline chaser bolus, scan delay 70 s; oral contrast) was also used for attenuation correction. From MDCT data mean scan range and duration, occurrence of contrast media-induced artefacts, and mean CT densities of jugular (jv) and subclavian (scv), superior (vcs) and inferior (vci) caval, portal (pv), and bilateral external iliac veins, pulmonary (ap) and iliac arteries, descending thoracic and abdominal aorta, all cardiac chambers, as well as both liver lobes, spleen, adrenal glands and kidneys were determined. Results: Attenuation corrected PET images were free of contrast media-related image artefacts. Homogeneous contrast enhancement was found in the mediastinal veins (right/left jv 171 ± 34/171 ± 35, scv 127 ± 50/127 ± 40, vcs 153 ± 36 HU) and arteries (e.g. ap 145 ± 26/151 ± 26). Cardiac chambers, abdominal vessels (e.g. vci 138 ± 24, pv 159 ± 25 HU), and parenchymal organs revealed sufficient and homogenous contrast-enhancement in all cases. No beam-hardening artefacts occurred in the neighbourhood of the subclavian veins. Conclusion: The chosen whole-body ¹⁸F-FDG 16-slice PET-CT protocol allowed for craniocaudal CT scanning with high vessel and parenchymal contrast revealing no IV contrast-media induced artefacts in attenuation-corrected PET data sets.

Zusammenfassung

Ganzkörper-Untersuchungen durch ¹⁸F-FDG-PET-CT erfordern die Anpassung der für Mehrzeilen-Spiral-CT etablierten Untersuchungsprotokolle. Ziel dieser Studie war die Evaluation eines optimierten Kontrastmittel (KM)-gestützten CT-Protokolls für die hochauflösende 16-Zeilen-PET-CT des Ganzkörpers. Patienten, Methoden: 205 Patienten (51,9 ± 12,4 Jahre) erhielten im Rahmen ihres Tumorstagings eine ¹⁸F-FDG-PET-CT des Ganzkörpers (Biograph Sensation 16, Siemens: 16 ˟ 1,5 mm; 120 ml KM 3 ml/s; Scandelay 70 s; FDG 4 MBq/kg KG). Mittels ROI-Technik wurden Dauer/Länge des CT-Scans, Auftreten von KM-induzierten Artefakten, mittlere CT-Dichtewerte [HU] in den Vv. jugulares int., subcl. (scv), cava sup. (svc) und inf. (ivc), porta (pv) und iliacae ext., den Aa. pulmonales (pa), der Aorta thoracalis desc. und abd., den Herzhöhlen, bd. Leberlappen, Milz, Nebennieren, Nieren und Aa. iliacae ext. untersucht (e-soft®-Workstation). Ergebnisse: Die Ganzkörper-PET-CT-Untersuchungen wiesen hohe diagnostische Qualität auf (CT-Scandauer 15,3 ± 2,1 s). Ein homogenes KM-Enhancement wiesen Jugularvenen (re./Ii. 171 ± 34/171 ± 35 HU), mediastinale Venen (scv re./li. 127 ± 50/127 ± 41 HU; svc 153 ± 36 HU) und Arterien (pa re./li. 145 ± 26/151 ± 26 HU) und Herzhöhlen (z. B. RA 149 ± 25 HU) auf (max. Dichte re./li. scv 279/277 HU bzw. vcs 235 HU). Die abdominellen Gefäße (z. B. ivc 138 ± 24, pv 159±25, aa 149 ± 25 HU) und parenchymatösen Oberbauchorgane (re. Leberlappen 106 ± 21, Milz 113 ± 17 HU) zeigten ein diagnostisch suffizientes, homogenes Enhancement ohne KM-induzierte Artefakte. Schlussfolgerung: Das gewählte PET-CT-Protokoll erlaubt eine 16-Zeilen-CT-Untersuchung des Ganzkörpers in kraniokaudaler Scanrichtung mit exzellentem Gefäß- und Parenchymkontrast ohne Induktion von KM-induzierten Artefakten in den mediastinalen Venen sowie den Schwächungskorrigierten PET-Daten.

Keywords

CT - PET-CT - tumour staging - intravenous CT contrast agent

Schlüsselwörter

CT - PET-CT - Staging - intravenöse CT-Kontrastmittel

^* K. U. Juergens and M. L. Oei contributed equally to this manuscript.

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