Endocrine Abstracts

Purpose: To analyze CT signs and parameters of vascularization of pulmonary neuroendocrine tumours (PNT) and their relationship with the development of ACTH ectopic syndrome.

Materials and methods: 23 patients with PNT were evaluated with contrast-enhanced MDCT. Arterial and venous phases were obtained at 10 and 35 seconds after the attenuation of 200 HU at the descending aorta, a delayed phase was at 6–8 min after the start of injection of contrast media. The final diagnosis was established after histological and immunohistochemical analyses. “Typical carcinoid” (16 patients), “atypical carcinoid” (7) were revealed. ACTH ectopic syndrome was in 9 (56,3%) patients with TC and in 2 (28,6%) with AC. The following qualitative signs were analyzed at CT scans: localization of PNT, shape (round, oval, irregular), contours (smooth, tuberous, spiculate), its relationship with bronchus/vessel (stenosis, invasion, intimate adherence, presence of a feeding vessel), structure (necrosis and calcifications (localization and size). The surrounding parenchyma (ground glass opacity, lymphangitic carcinomatosis, areas of fibrosis, atelectasis, infiltrative changes), pleural thickening, bronchiectasis, pleural effusion were analyzed. The following quantitative signs were analyzed: the size of the PNT and the largest regional lymph node, patterns of the time-density curves (TDC). The precontrast density, peak height in density (PH: the maximum value of the TDC) and S/A ratio (the ratio of the PH of lesion to aorta) were recorded. Precontrast density and enhancement patterns of lesions were recorded. Perfusion of the lesions was calculated.

Results: The moderate relationship between ACTH ectopic syndrome and following CT features was revealed: perfusion (r = 0.567, P = 0.007), S/A ratio (r = 0.504, P = 0.02) and size of lesion (0.540, P = 0.008). A very good quality of predictive model for the perfusion of the lesion and its size was determined (AUC 0.827, P = 0.011, AUC 0.811, P = 0.012). Perfusion rate 0.86 ml/min per ml and tumor size 12.5 mm ware the cut-off value (sensitivity 72.7%, specificity 80%, sensitivity 100%, specificity 54.5%). A good quality of predictive model for S/A ratio (AUC 0.791, P = 0.024) was determined. S/A ratio 36.8% was the cut-off value (sensitivity 54.5%, specificity 100%).

Conclusions: The following findings: small size of the lesion (less than 12.5 mm) and low parameters of perfusion and S/A ratio allow us to suspect a hormonal activity of carcinoid tumor and, consequently, a more malignant nature of tumour, which should be taken into account in treatment strategy.