Fokal FDG-Tutulumlu Tiroid İnsidentalomalarında SUVmax'ın Malignite ile İlişkisi

Öz

18F-Florodeoksiglukoz pozitron emisyon tomografisi/bilgisayarlı tomografi (FDG PET/BT) ile saptanan tiroid insidentalomaları (Tİ’ler), özellikle fokal FDG tutulumu varlığında, artmış malignite riski ile ilişkilidir. Maksimum standartlaştırılmış tutulum değeri (SUVmax) gibi kantitatif PET/BT parametreleri kapsamlı şekilde incelenmiş olsa da, mevcut yönetim kılavuzları esas olarak nodül boyutu ve ultrasonografik özelliklere dayanmaktadır. Bu çalışmanın amacı, FDG tutulumu olan Tİ’lerde PET/BT’den elde edilen radyolojik parametrelerin malignite açısından ek bilgi sağlayıp sağlamadığını değerlendirmektir. Bu retrospektif, tek merkezli çalışmaya PET/BT’de fokal FDG tutulumu olan Tİ saptanan, ultrasonografik değerlendirme ve sitolojik ve/veya histopatolojik doğrulama yapılan hastalar dahil edilmiştir. Demografik özellikler, PET/BT görüntülerinden elde edilen metabolik parametreler, ultrasonografik bulgular ve anatomik lokalizasyon kaydedilmiştir. Benign ve malign lezyonlar karşılaştırılmıştır. Optimal SUVmax cut-off değerini belirlemek için ROC analizi yapılmış ve malignite ile bağımsız olarak ilişkili değişkenleri belirlemek amacıyla lojistik regresyon analizleri kullanılmıştır. Toplam 53 hasta dahil edilmiş olup, bunların 13’ünde (%24,5) malign tiroid lezyonu saptanmıştır. Malign nodüller, benign nodüllere kıyasla anlamlı derecede daha yüksek SUVmax değerleri göstermiştir (p=0,008). ROC analizi, benign ve malign nodülleri ayırt etmek için 5.8’lik bir SUVmax cut-off değeri belirlemiştir (AUC: 0,748). İstmus yerleşimi de çok değişkenli analizde anlamlılığını korumuştur (p=0,037). Diğer morfolojik veya ultrasonografik parametreler anlamlı bulunmamıştır. Fokal FDG tutulumu olan Tİ olgularında, SUVmax ≥5.8 değeri artmış malignite riski ile ilişkilidir ve risk sınıflandırmasında tamamlayıcı bilgi sağlayabilir. Ancak SUVmax, tek başına karar verme aracı olarak değil, klinik ve ultrasonografik bulgularla birlikte yorumlanmalıdır.

Anahtar Kelimeler

• Tiroid İncidentaloma
• FDG PET/CT
• SUVmax
• Malignite Riski
• İnce İğne Aspirasyon Biyopsi

Association of SUVmax with Malignancy in Focal FDG-Avid Thyroid Incidentalomas

Öz

Thyroid incidentalomas (TIs) detected on 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) are associated with an increased risk of malignancy, particularly in the presence of focal FDG uptake. While quantitative PET/CT parameters, such as the maximum standardized uptake value (SUVmax), have been extensively studied, current management guidelines primarily rely on nodule size and ultrasonographic features. This study aimed to evaluate whether PET/CT-derived radiological parameters provide additional information for malignancy in FDG-avid TIs. This retrospective single-center study included patients with focal FDG-avid thyroid incidentalomas detected on PET/CT who underwent ultrasonographic evaluation and cytological and/or histopathological confirmation. Demographic characteristics, metabolic parameters derived from PET/CT scans, ultrasonographic findings and anatomical localization were documented. Benign and malignant lesions were compared. Receiver operating characteristic (ROC) analysis was conducted to determine the optimal SUVmax cut-off value and logistic regression analyses were employed to identify variables independently associated with malignancy. A total of 53 patients were included, with 13 (24.5%) having malignant thyroid lesions. Malignant nodules demonstrated significantly higher SUVmax values than benign nodules (p=0.008). ROC analysis established a SUVmax cut-off value of 5.8 for discrimination between benign and malignant nodules (AUC: 0.748). Isthmus localization also remained significant in multivariate analysis (p=0.037). No other morphologic or ultrasonographic parameters were significant. In cases of focal FDG-avid TIs, an SUVmax value of ≥5.8 is associated with an increased risk of malignancy and may provide complementary information in risk stratification. However, SUVmax should be interpreted alongside clinical and ultrasonographic findings, not as a standalone decision-making tool.

Anahtar Kelimeler

• Thyroid incidentaloma
• FDG PET/CT
• SUVmax
• Malignancy risk
• Fine-needle aspiration biopsy

Kaynakça

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