Kontrastlı BT'nin Karaciğer Lezyonlarının Karakterizasyonunda FDG PET'e Katkısı ve Kantitatif Etkileri

Öz

Amaç: Çalışmadaki amaçlarımız, primer-sekonder karaciğer malignitelerinin boyut, lokalizasyon açısından saptanması için kontrastlı/kontrastsız 18F-FDG-PET/BT taramalarının tanısal etkinliğini karşılaştırmak, kontrast maddenin karaciğer lezyonlarının ve normal karaciğer dokusunun SUVmaks değerlerindeki kantitatif etkilerini araştırmak, kontrast madde uygulamasından sonra SUVmaks ölçümlerindeki hata düzeyini belirlemekti. Materyal ve Metod: Bu çalışma, primer-sekonder karaciğer malignitesi şüphesi olan bireyleri içeren prospektif çalışmadır. Hastalara bölgesel kontrastsız ve kontrastlı PET/BT taramaları yapılmıştır. Malign kabul edilen lezyonların boyutu, lokalizasyonu, dansitesi, görsel derecelendirme skoru, SUVmaks değerleri ile normal karaciğer dokusunun HU, SUVmaks değerleri kaydedilmiştir. Bulgular: Toplam 97 karaciğer lezyonu tespit edildi. Lezyonların görsel derecelendirme skorları, normal karaciğer dokusu için HU ve SUVmaks değerleri kontrast madde verilmesiyle anlamlı olarak arttı. 1cm'den büyük lezyonların HU değerlerinde ve 1cm'den büyük santral yerleşimli lezyonların SUVmaks değerlerinde istatistiksel anlamlı artış vardı. Atenüasyon düzeltme algoritmaları ile kontrast madde uygulamasından sonra hesaplanan SUVmaks değerlerinde normal karaciğer dokusu için ortalama %5 ve karaciğer lezyonları için %6 hatalı artış vardı. Sonuç: Kontrast madde kullanımı, PET/BT ile hepatik lezyonların saptanmasını, lokalizasyonunu ve karakterizasyonunu önemli ölçüde iyileştirmektedir.

Anahtar Kelimeler

• Kontrast madde
• PET/BT
• karaciğer lezyonu

The Contribution of Contrast Enhanced CT to FDG PET on Characterization of Liver Lesions and It’s Quantitative Effects

Öz

Background: The goals of this study was to evaluate the diagnostic capability of enhanced/unenhanced 18F-FDG-PET/CT scans for identifying primary-secondary liver malignancies in terms of size and localization, to decide the quantitative impact of contrast agent on the SUVmax values of liver lesions and normal liver tissue, and to assess the impact in SUVmax metrics following contrast substance administration. Materials and Methods: This was a prospective research that included patients with suspicious primary and secondary hepatic cancers. Patients had non-enhanced & enhanced regional PET/CT examinations. The dimen-sion, position, densities (HU), visually assessment outcome, and SUVmax values for all pathological lesions were recorded, as well as the HU and SUVmax data of normal hepatic tissue. Results: There were 97 liver lesions in total. Visually assessment outcome of lesions, the introduction of a contrast substance considerably enhanced the HU and SUVmax measurements for normal hepatic tissue. The HU measurements for lesions bigger than 1cm increased statistically significantly, as did the SUVmax levels of centralized lesions bigger than 1cm. The attenuation adjustment procedures, resulted in an average inaccuracy in computed SUVmax values at the ratio of %5 for normal liver tissue and %6 for all hepatic pathologies follow-ing the contrast substance delivery. Conclusions: The inclusion of contrast substance increases the identification, localization, and characterization of the liver lesions with PET/CT substantially.

Anahtar Kelimeler

• Contrast material
• PET/CT
• liver lesion

Kaynakça

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