Investigating the Existence of Quantum Metabolic Values in Non-Hodgkin’s Lymphoma by 2-Deoxy-2-[F-18]fluoro-d-glucose Positron Emission Tomography

Implications of Ambient Glucose Variation on the Target-to-Background Ratio of Hepatic Tumors By (18)FDG-PET Imaging

Objectives:

To investigate the effects of ambient glucose on quantitative analysis of hepatic tumors on 2-deoxy-2-(¹⁸F)-fluoro-D-glucose (¹⁸FDG) positron emission tomography (PET) and to establish a method for glucose correction.

Patients and Methods:

Eighty-six patients with hepatic lesions identified on ¹⁸FDG PET/computed tomography (CT) were analyzed. The serum glucose level (Glc) was recorded prior to imaging, and the maximum standardized uptake value (SUV) in the hepatic tumors and the average SUV in normal liver were determined. The inverse relationship of SUV to glucose can be defined as d (SUV)/d (Glc) = g*SUV/(Glc), where g is the glucose sensitivity. Simulations using glucose level from 70 to 250 mg/dl were performed to evaluate the effects of Glc on the maximum SUV of malignant hepatic lesions and normal liver.

Results:

By logarithmic transformation and linear regression, g for metastasis was significantly higher than that for normal liver (−0.636 ± 0.144 vs. −0.0536 ± 0.0583; P = 0.00092). Simulation studies showed that the SUV in malignant lesions will decrease rapidly when Glc level is >120 mg/dl, while background liver remains relatively constant up to 250 mg/dl.

Conclusion:

The tumor FDG uptake is much more sensitive to ambient glucose level variation than the background liver. Therefore, correction by the glucose sensitivity factor will result in more accurate SUV measurements and make semi-quantitative analysis of ¹⁸FDG PET scans more reliable.

Revisiting the Marrow Metabolic Changes after Chemotherapy in Lymphoma: A Step towards Personalized Care

Purpose. The aims were to correlate individual marrow metabolic changes after chemotherapy with bone marrow biopsy (BMBx) for its potential value of personalized care in lymphoma. Methods. 26 patients (mean age, 58 ± 15 y; 13 female, 13 male) with follicular lymphoma or diffuse large B-cell lymphoma, referred to FDG-PET/CT imaging, who had BMBx from unilateral or bilateral iliac crest(s) before chemotherapy, were studied retrospectively. The maximal standardized uptake value (SUV) was measured from BMBx site over the same area on both initial staging and first available restaging FDG-PET/CT scan. Results. 35 BMBx sites in 26 patients were evaluated. 12 of 35 sites were BMBx positive with interval decrease in SUV in 11 of 12 sites (92%). The remaining 23 of 35 sites were BMBx negative with interval increase in SUV in 21 of 23 sites (91%). The correlation between SUV change over the BMBx site before and after chemotherapy and BMBx result was significant (P < 0.0001). Conclusions. This preliminary result demonstrates a strong correlation between marrow metabolic changes (as determined by FDG PET) after chemotherapy and bone marrow involvement proven by biopsy. This may provide a retrospective means of personalized management of marrow involvement in deciding whether to deliver more extended therapy or closer followup of lymphoma patients.

Standardised uptake value of 18F-FDG on staging PET/CT in newly diagnosed patients with different subtypes of non-Hodgkin's lymphoma

OBJECTIVES

Positron emission tomography using 2-[fluorine-18]-fluoro-2-deoxy-D-glucose ((18) F-FDG) is considered to be the most beneficial imaging method for staging patients with non-Hodgkin's lymphoma (NHL). The intensity of (18) F-FDG accumulation may be determined by calculating the so-called standardised uptake value (SUV). The study aimed at assessing the benefit of SUV(max) determination in staging (18) F-FDG PET/CT in untreated patients with NHL.

METHODS

One hundred and forty-nine initial staging (18) F-FDG PET/CT scans performed in patients with NHL between January 2007 and August 2009 were assessed, and the SUV(max) was determined.

RESULTS

The highest mean and median values of SUV(max) were observed in patients with diffuse large B-cell lymphoma (DLBCL), the lowest mean and median values were found in small lymphocytic lymphoma. The overlap in SUV(max) < 10 between DLBCL and the other subgroups of NHL was very significant. Statistically, no correlation was found between the lactate dehydrogenase and SUV(max) values. On the other hand, a correlation of the Ki-67 proliferative index of tumour cells and SUV(max) was revealed (r = 0.409, P < 0.001). The geometric mean of SUV(max) in patients with Ki-67 ≤ 60 and those with Ki-67 > 60 was 8.8 and 14.3, respectively (P < 0.001).

CONCLUSIONS

The results confirm that SUV(max) is not beneficial for making a more precise diagnosis in most patients with NHL. Correlation of SUV(max) with the Ki-67 values suggests that SUV(max) might have a prognostic values in NHL.

Prognostic value of tumor 18F-FDG uptake in patients with untreated extranodal natural killer/T-cell lymphomas of the head and neck

Although 18F-FDG PET has been used to monitor patients with lymphoma, its usefulness has not been determined in patients with extranodal natural killer/T-cell lymphoma (ENKTL). Therefore, we evaluated whether pretreatment 18F-FDG uptake was a predictor of survival in patients with ENKTL of the head and neck.

METHODS

Pretreatment staging work-ups, including whole-body 18F-FDG PET, were performed on 21 patients with previously untreated head and neck ENKTL. Fourteen patients received combined chemoradiotherapy (n = 14), and 7 received chemotherapy or radiotherapy alone. We assessed the relationship of maximum standardized uptake value (SUVmax) of the tumor to disease-specific survival (DSS) and to clinical parameters, including sex, age, Ann Arbor stage, performance status, International Prognostic Index score, presence of B symptoms, lactate dehydrogenase level, local tumor invasion (LTI), and lymph node involvement.

RESULTS

Mean tumor SUVmax was 5.5 and was significantly higher in patients with elevated lactate dehydrogenase level, LTI, or poor response to initial therapy (P < 0.05). All 5 nonresponders to therapy had an SUVmax greater than 5.5, whereas 11 of 16 responders (69%) had an SUVmax less than or equal to 5.5 (mean SUVmax, 8.4 vs. 4.5). Univariate analysis showed that an International Prognostic Index score greater than or equal to 2, LTI, and SUVmax category were significant predictors of 3-y DSS, although only the SUVmax category remained an independent determinant of DSS on multivariate analysis (P = 0.023).

CONCLUSION

High tumor 18F-FDG uptake was closely associated with local tumor invasion, contributing to unfavorable treatment and survival outcomes in patients with ENKTL of the head and neck.