Restaging of patients with lymphoma

Summary

Aim: Assessment of the clinical benefit of i.v. contrast enhanced diagnostic CT (CE-CT) compared to low dose CT with 20 mAs (LD-CT) without contrast medium in combined [¹⁸F]-FDG PET/CT examinations in restaging of patients with lymphoma. Patients, methods: 45 patients with non-Hodgkin lymphoma (n = 35) and Hodgkin's disease (n = 10) were included into this study. PET, LD-CT and CECT were analyzed separately as well as side-by-side. Lymphoma involvement was evaluated separately for seven regions. Indeterminate diagnoses were accepted whenever there was a discrepancy between PET and CT findings. Results for combined reading were calculated by rating indeterminate diagnoses according the suggestions of either CT or PET. Each patient had a clinical follow-up evaluation for >6 months. Results: Region-based evaluation suggested a sensitivity/specificity of 66/93% for LD-CT, 87%/91% for CE-CT, 95%/96% for PET, 94%/99% for PET/LD-CT and 96%/99% for PET/CE-CT. The data for PET/CT were obtained by rating indeterminate results according to the suggestions of PET, which turned out to be superior to CT. Lymphoma staging was changed in two patients using PET/ CE-CT as compared to PET/LD-CT. Conclusion: Overall, there was no significant difference between PET/LD-CT and PET/CE-CT. However, PET/CE-CT yielded a more precise lesion delineation than PET/LD-CT. This was due to the improved image quality of CE-CT and might lead to a more accurate investigation of lymphoma.

Zusammenfassung

Ziel: Vergleich von kombinierter PET/CT Untersuchung mit [¹⁸F]-FDG inkl. i.v.-Kontrastmittel (CE-CT) und PET/CT in Low-dose-Technik mit 20 mAs ohne Kontrastmittelgabe (LD-CT) beim Restaging von Patienten mit Morbus Hodgkin 0(HL) und Non-Hodgkin-Lymphom (NHL). Patienten, Methodik: Bei 45 Patienten mit NHL (n = 35) und HL (n=10) wurden die Einzelmodalitäten (PET, LD-CT und CE-CT) jeweils getrennt wie auch in Zusammenschau bzw. nach Fusion ausgewertet. Hierbei erfolgte eine Regionenbasierte Auswertung (zervikale, thorakale, abdominale, und pelvine Lymphknoten, extranodaler Befall, Knochenbefall, Milzbefall). Bei diskrepanten PET/CT-Befunden erfolgte entweder eine CT- oder eine PET-basierte Evaluation. Ergebnisse: Die Sensitivität bzw. Spezifität betrug 66%/93% für die LD-CT, 87%/91% für die CE-CT, 95%/96% für die PET, 94%/99% für die PET/LD-CT und 96%/99% für die PET/CE-CT. Das Staging nach Ann-Arbor veränderte sich mittels PET/CE-CT im Vergleich zu PET/LDCT bei zwei Patienten. Schlussfolgerung: Bei Lymphom- Patienten wurde kein signifikanter Unterschied zwischen PET/CE-CT und PET/LD-CT nachgewiesen. Die verminderte Bildqualität der LD-CT und fehlende i.v.-Kontrastierung erschwerten die Beurteilbarkeit unklarer [¹⁸F]-FDG-Mehranreicherungen und anatomische Ausdehnung der Herde.

Keywords

[¹⁸F]-FDG - PET/CT - Hodgkin's disease - non-Hodgkin lymphoma - low dose CT - diagnostic CT

Schlüsselwörter

[¹⁸F]-FDG - PET/CT - Morbus Hodgkin - Non-Hodgkin-Lymphom

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