18F-fluorodeoxyglucose PET/CT evaluations for multiple myeloma lack standardization

NEW YORK — High discordance of 18F-fluorodeoxyglucose PET/CT evaluations for the risk stratification of multiple myeloma occurred between radiologists and nuclear medicine physicians, according to study results presented at Lymphoma & Myeloma 2015.

18F fluorodeoxyglucose (18F-FDG) PET/CT — which offers a whole-body functional and morphological evaluation — provides data on the maximum standardized uptake volume (SUVmax) and focal osseous lesions used for the risk stratification of patients with multiple myeloma. However, the use of 18F-FDG PET/CT may be limited by the non-standardization of visual criteria and the lack of inter–observer reproducibility when reporting PET results, according to study background.

Tülin Firatli-Tuglular, MD, of the department of internal medicine in the division of hematology at Marmara University Hospital in Istanbul, Turkey, and colleagues sought to compare the detection rates of focal osteolytic lesions on the CT component of 18F-FDG PET/CT by radiologists and nuclear medicine physicians.

Radiologists and nuclear medicine physicians reviewed the CT component of 18F-FDG PET/CT from 22 patients with newly diagnosed multiple myeloma. Researchers considered 18F-FDG uptake positive in the following scenarios:

• The oncolytic lesion was at least 1 cm with an SUVmax that exceeded 2.5;
• The oncolytic lesion ranged from 0.5 cm to 1 cm with an SUVmax that exceeded 1.5; and
• The oncolytic lesion was smaller than 5 mm in diameter with any SUVmax.

Researchers calculated a concordance rate of 0.82 and a ĸ of 0.51, indicating moderate concordance.

There were more osteolytic lesions in CT images of 18F-FDG PET/CT when reviewed by radiologists than when reviewed by nuclear medicine physicians (86.4% vs. 68.2%; P = .023).

Radiologists detected all of the FDG-avid focal lesions on the CT component. However, 21.1% of osteolytic focal lesions were missed on the PET component.

“18F-FDG PET/CT evaluations for multiple myeloma should be standardized in order to improve the inter–observer reproducibility,” Firatli-Tuglular and colleagues wrote. – by Alexandra Todak

For more information:

Firatli-Tuglular T, et al. Abstract P3. Presented at: Lymphoma & Myeloma 2015; An International Congress on Hematologic Malignancies; Oct. 22-24, 2015; New York, New York.

Disclosure: The researchers report no relevant financial disclosures.