CT scan

Using F-18 labeled fluorodeoxyglucose (18F-FDG) as a tracer in positron emission tomography/computed tomography (PET/CT) can aid in determining risk level in patients with gastrointestinal stromal tumor (GIST), according to a study published in the European Journal of Medical Research.

In the study, patients with moderate-risk and high-risk GIST lesions showed abnormally increased levels of 18F-FDG uptake. This was in contrast to those with very low- and low-risk lesions which did not show increased 18F-FDG metabolism. One high-risk patient did not have increased 18F-FDG uptake but did have multiple lesions.

“When the biological risk cannot be judged by tumor size and shape, the 18F-FDG metabolic level can be used to determine the biological risk of GIST and whether high-risk lesions involve other tissues and organs, as it more comprehensively reflects the distribution of lesions, the activity of tumor cells and the stage of the disease,” the authors said.

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Out of a total 32 patients, 26 had single lesions while the remaining 6 had multiple lesions. A total of 14 lesions were observed in the 6 patients with multiple lesions. Of the 26 patients with a single lesion, 17 were categorized as very low- or low-risk based on pathological and clinical examinations. 18F-FDG imaging showed no increased glucose metabolism in any of these 17 patients.

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Moderate risk lesions were identified in 5 of the patients with single lesions. All of these lesions were located in the stomach, had sizes between 2.8-6.4 cm, and had 18F-FDG metabolic standardized uptake values (SUVmax) values between 2.3 and 3.6.

The high-risk single lesions included 2 gastric tumors, 1 tumor located in the jejunum and ileum, and 1 located in the colon. The gastric lesions were 3.6 and 12.7 cm in size and had SUVmax values of 4.4 and 7.7, respectively. The jejunum and ileum tumor had an SUVmax value of 3.8 and was 4.2 cm in size while the colon tumor was 4.2 cm in size and had an SUVmax of 6.8.

Among the 6 patients with multiple lesions, 3 tumors were located in the stomach, 3 in the liver, 3 in the jejunum and ileum, 3 in the mesentery, 1 in the colon, and 1 in the abdominal and pelvic lymph nodes. Elevated glucose metabolism was observed in 13 out of the 14 lesions from this patient group.

“These results indicate that the level of glucose metabolism of tumor cells with vigorous mitosis is abnormally increased and creates a higher biological risk,” the authors concluded.

A total of 32 patients with GIST were included in the study. The patients were aged between 37 and 68 years and included 23 males and 9 females.


Du W, Cui G, Wang K, Li S. Clinical significance of 18F-FDG PET/CT imaging in 32 cases of gastrointestinal stromal tumors. Eur J Med Res. 2022;27(1):182. doi:10.1186/s40001-022-00806-9