What parameters from super(18)F-FDG PET/CT are useful in evaluation of adrenal lesions?

• Published in: European journal of nuclear medicine and molecular imaging Vol. 41; no. 12; pp. 2273 - 2280
• Main Authors: Kunikowska, Jolanta, Matyskiel, Renata, Toutounchi, Sadegh, Grabowska-Derlatka, Laretta, Koperski, Aaukasz, Krolicki, Leszek
• Format: Journal Article
• Language: English
• Published: 01.12.2014
• Subjects: Mycobacterium
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-014-2844-1

Purpose: Prior studies have suggested that super(18)F-FDG PET/CT can help characterize adrenal lesions and differentiate adrenal metastases from benign lesions. The aim of this study was to assess the value of super(18)F-FDG PET/CT for the differentiation of malignant from benign adrenal lesions. Methods: This retrospective study included 85 patients (47 men and 38 women, age 63.8 plus or minus 10.8 years) who had undergone super(18)F-FDG PET/CT (60 min after injection 300 - 370 MBq super(18)F-FDG; Biograph 64 scanner) for evaluation of 102 nonsecreting adrenal masses. For semiquantitative analysis, the maximum standardized uptake value (SUVmax), adrenal to liver (T/L) SUVmax ratio, mean CT attenuation value and tumour diameter were measured in all lesions and compared with the pathological findings. Results: Malignant adrenal tumours (68 % of evaluated tumours) had a significantly higher mean SUVmax (13.0 plus or minus 7.1 vs. 3.7 plus or minus 3.0), a higher T/L SUVmax ratio (4.2 plus or minus 2.6 vs. 1.0 plus or minus 0.9), a higher CT attenuation value (31.9 plus or minus 16. 7 HU vs. 0.2 plus or minus 25.8 HU) and a greater diameter (43.6 plus or minus 23.7 mm vs. 25.6 plus or minus 13.3 mm) than benign lesions. The false-positive findings were tuberculosis and benign phaeochromocytoma. Based on ROC analysis, a T/L SUVmax ratio >1.53, an adrenal SUVmax >5.2, an attenuation value >24 HU and a tumour diameter >30 mm were chosen as the optimal cut-off values for differentiating malignant from benign tumours. The areas under the ROC curves for the selected cut-off values were 0.96, 0.96, 0.88 and 0.77, respectively. A multivariate logistic regression model revealed that the T/L SUVmax ratio was an independent prognostic factor for malignancy (p<0.001); a CT attenuation value of >25 HU and a tumour diameter >30 mm had no additional individual importance in the diagnosis of malignancy. Conclusion: Using a T/L SUVmax ratio >1.53 and an adrenal SUVmax >5.2 in super(18)F-FDG PET/CT led to high diagnostic sensitivity, specificity and negative predictive value for characterizing adrenal tumours. The diagnostic accuracies of the two parameters were comparable, but T/L SUVmax ratio was an independent predictor of malignancy.