Dynamic18F-FDG PET-CT to Calculate the Glucose Metabolic Rate and Correlation With Histological Features in Uveal Melanoma

Abstract

 

Purpose:

 

To evaluate the feasibility of 3D dynamic ¹⁸F-FDG PET/CT for the diagnosis of uveal melanoma, and correlate the scintigraphic results with the histological features.

 

Methods:

 

Four patients (2 males, 2 females, mean age 52 yrs) affected by large uveal melanoma (mean thickness 10.67 mm) underwent dynamic 3D PET/CT (Gemini, Philips) immediately after i.v. injection of 296 MBq ¹⁸F-FDG. All the eye were enucleated. PET/CT images were analysed qualitatively (mild, moderate, intense uptake) and quantitatively drawing region of interests (ROIs) over the lesion and contralateral eye. The quantitative parameters calculated were Ki (min^-1), and the Glucose Metabolic Rate (MRglu, Mmol/min/100gr).

 

Results:

 

All lesions were well visualised at ¹⁸F-FDG PET-CT: one showed intense ¹⁸F-FDG uptake, and three moderate uptake. In the table are reported the Ki and MRglu values for the lesions and contra-lateral eye, and the histological findings.

 

Conclusions:

 

These results, obtained in a small number of patients, showed that dynamic ¹⁸F-FDG PET/CT is a sensitive technique (100%) for detection of uveal melanomas allowing to calculate the metabolic glucose rate. Uveal melanomas have higher glucose consumption at least more than twice or three times compared with contra-lateral normal eye. Lesions with high number of epithelioid cells and high vascular density showed higher glucose metabolic rate compared with spindle-shaped lesions with low vascular density. These preliminary results need to be confirmed in a large series of patients.  

 

Keywords: melanoma • imaging/image analysis: clinical