18F-Fluorocholine Uptake and Positron Emission Tomography Imaging in Rat Peritoneal Endometriosis

Abstract

Endometriosis is a debilitating disease that still needs surgery to be confirmed. Endometriosis is associated with increased plasma levels of phosphatidylcholines. F-fluorocholine ([F]FCH) is a radiopharmaceutical that is metabolized to phosphatidylcholine inside the cells and can be traced by positron emission tomography (PET). Here we evaluate [F]FCH as a potential tool for the noninvasive diagnosis of peritoneal endometriosis. Adult female Wistar rats had autologous uterine fragments dissected and grafted to the peritoneal wall to model peritoneal endometriosis. Ex vivo biodistribution assay and PET imaging studies were performed 30 minutes after [F]FCH administration. The [F]FCH uptake was 3-fold higher in endometriotic implant tissues than in muscle or peritoneum. Positron emission tomography imaging revealed the grafted uterine tissue in contrast to surrounding structures. Region-of-interest analysis of the reconstructed images showed higher accumulation of [F]FCH by endometriotic lesions, 0.34 (0.04)% of injected dose per gram of tissue (ID/g), in comparison with muscle tissue, 0.08 (0.01)% ID/g. However, sham implants with fat tissue were also detectable in PET imaging. These preliminary findings of [F]FCH uptake by ectopic uterine tissue implants and their localization by PET imaging encourage the future evaluation of this technique to detect small superficial endometriosis lesions in humans. Study protocols need to be further perfected and adapted for tests in women with endometriosis.

Positron emission tomography imaging of vascular endothelial growth factor with 64Cu-labeled bevacizumab for non-invasive diagnosis of endometriosis

“…Several PET tracers such as 16α- 18 F-fluoro-17β-estradiol ( 18 F-FES) and 18 F-fluorocholine have been investigated as endometriosis imaging agents. 23,24 While promising, critical limitations related to the physiological uptake of tracers restricted their use in clinic. 18 F-FES, shows high accumulation in the abdominal area, while 18 F-fluorocholine, a choline analog that reflects cellular proliferation, shows high urinary tract accumulation.…”

Molecular Imaging in Gynecology: Beyond Cancer

“…Silveira et al, for example, used a rat model of the disease to determine the uptake of [ 18 F]fluorocholine in superficial lesions. Although the activity concentration of the tracer in implanted endometriosis tissue was found to be 3-fold higher than that in the muscle and peritoneum, the biodistribution data revealed very high uptake in several healthy tissues, most notably (and problematically) the ovaries (15). More recently, Amartuvshin et al probed the value of a 64 Cu-labeled variant of the vascular endothelial growth factor-targeting antibody bevacizumab for the delineation of subcutaneous endometriosis lesions.…”

Image quality evaluation for two different positron emitters in a preclinical PET scanner

“…Currently in Brazil, there are six centers of preclinical molecular imaging using PET routinely [3], one of them installed in the Molecular Imaging Laboratory (LIM) of Nuclear Technology Development Center (CDTN). Although most studies conducted at LIM/CDTN involve 18 F-labeled radiopharmaceuticals [4][5][6][7][8][9], some effort has been made in studies with 11 C-labeled radiopharmaceuticals [10,11]. In this context, it is important to keep in mind that differences in physical and chemistry properties of radionuclides can results in different performances of the PET scanner [12].…”