Comparative evaluation of 11C-methionine and 18F-fluorodeoxyglucose positron emission tomography for distinguishing between primary central nervous system lymphoma and isocitrate dehydrogenase-wildtype glioblastoma.

PURPOSE: Distinguishing between primary central nervous system lymphoma (PCNSL) and isocitrate dehydrogenase (IDH)-wildtype glioblastoma is important for therapeutic decision-making. This study aimed to compare the performance of 11C-methionine (MET) and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for distinguishing between these two major malignant brain tumors. METHODS: We retrospectively conducted qualitative and semiquantitative analyses of pre-treatment MET and FDG PET/computed tomography (CT) images of 22 patients with PCNSL and 64 patients with IDH-wildtype glioblastoma. For semiquantitative analysis, we calculated the tumor-to-normal tissue (T/N) ratio by dividing the maximum standardized uptake value (SUV) for the tumor (T) by the average SUV for the normal tissue (N). For performance evaluation, we employed receiver operating characteristic curve analysis and calculated the areas under the curve (AUC) values. RESULTS: In the qualitative analysis, all PCNSLs and IDH-wildtype glioblastomas were MET-positive, while 95% and 84% of PCNSLs and IDH-wildtype glioblastomas, respectively, were FDG-positive. Eleven patients were excluded from the FDG PET/CT semiquantitative analysis because of hyperglycemia. There was no difference in MET T/N ratio between PCNSL and IDH-wildtype glioblastoma (p = 0.37). FDG T/N ratio was significantly higher in PCNSL than in IDH-wildtype glioblastoma (p < 0.001). The AUC value for distinguishing PCNSL from IDH-wildtype glioblastoma was significantly higher for the FDG T/N ratio (0.871) than for the MET T/N ratio (0.565) (p = 0.0027). CONCLUSION: MET PET could detect both PCNSL and IDH-wildtype glioblastoma, but unlike FDG PET, it could not distinguish between these two major malignant brain tumors.

Feasibility of 11C-Pittsburgh compound B positron emission tomography/computed tomography for treatment monitoring with Tafamidis in a patient with transthyretin cardiac amyloidosis.

We present a 77-year-old woman with wild-type ATTR cardiac amyloidosis (ATTR-CA) who presented with dyspnea, arrhythmia, and elevated NT-pro BNP. Initial imaging including cardiac MRI, PYP scintigraphy, PiB PET/CT and NaF PET/CT revealed cardiac abnormalities. Tafamidis treatment was initiated. After 14 months, symptomatic improvement and reduced NT-pro BNP were observed. Cardiac MRI and PYP scintigraphy showed no significant change and increased NaF accumulation, while PiB PET/CT showed decreased amyloid deposition, suggesting that it may be superior to NaF PET/CT in assessing the therapeutic effect of tafamidis in ATTR-CA.

Feasibility of PiB positron emission tomography/computed tomography for treatment monitoring with Tafamidis in a patient with transthyretin cardiac amyloidosis.

We present a 77-year-old woman with wild-type ATTR cardiac amyloidosis (ATTR-CA) who presented with dyspnea, arrhythmia, and elevated NT-pro BNP. Initial imaging including cardiac MRI, PYP scintigraphy, PiB PET/CT and NaF PET/CT revealed cardiac abnormalities. Tafamidis treatment was initiated. After 14 months, symptomatic improvement and reduced NT-pro BNP were observed. Cardiac MRI and PYP scintigraphy showed no significant change and increased NaF accumulation, while PiB PET/CT showed decreased amyloid deposition, suggesting that it may be superior to NaF PET/CT in assessing the therapeutic effect of tafamidis in ATTR-CA.

Tumor-to-blood pool ratio of 18F-fluorodeoxyglucose-positron emission tomography's standardized uptake value as a useful parameter indicating malignant transformation in pancreatic branch-duct intraductal papillary mucinous neoplasm compared to the international Fukuoka guidelines: a retrospective cohort study from surgical resections.

BACKGROUND: Identifying malignant transformation in pancreatic branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) remains challenging, but the standardized uptake value (SUV) obtained from 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET)/CT has the potential to become a valuable parameter for differentiation. This study aimed to assess the effectiveness of SUV of FDG-PET/CT in distinguishing low-grade dysplasia (LGD), high-grade dysplasia (HGD), and intraductal papillary mucinous carcinoma (IPMC) within BD-IPMNs. METHODS: We assessed 58 patients with confirmed BD-IPMN undergoing surgery between 2008 and 2022. Receiver operating characteristic curves were plotted using the tumor-to-blood pool ratio (TBR) of FDG-PET/CT in two scenarios: one considering HGD + IPMC as positive and the other considering only IPMC as positive. RESULTS: In the cohort of 58 cases, there were 39 females, and the median age was 71 years. The median TBR value was 1.45 (range, 0.35-25.44). The TBRs exhibited a significant correlation with each histopathology (p < 0.001). Furthermore, in the multivariate analysis, TBR was independently significant in both scenarios, with HGD + IPMC defined as malignant (p = 0.001) and with only IPMC defined as malignant (p = 0.024). CONCLUSIONS: TBR might have the potential to serve as a valuable parameter for indicating malignant transformation in pancreatic BD-IPMNs.

Relationship between [18F]FDG PET/CT and metabolomics in patients with colorectal cancer.

INTRODUCTION: Advances in metabolomics have significantly improved cancer detection, diagnosis, treatment, and prognosis. OBJECTIVES: To investigate the relationship between metabolic tumor volume (MTV) using 2-deoxy-2-[18F]fluoro-D-glucose (FDG) positron emission tomography (PET)/ computed tomography (CT) and metabolomics data in patients with colorectal cancer (CRC). METHODS: The metabolome in tumor tissues was analyzed using capillary electrophoresis time-of-flight mass spectrometry in 33 patients with newly diagnosed CRC who underwent FDG PET/CT before treatment and had tumor tissue post-surgery. Based on the FDG PET data, MTV was calculated and was dichotomized according to the median value, and tumors were divided into low-MTV and high-MTV tumors. Metabolomics data were compared between the low-MTV and high-MTV tumors. RESULTS: The levels of most glycolysis-related metabolites were not different between low-MTV and high-MTV tumors. The level of component of the initial part of the tricarboxylic acid (TCA) cycle, citrate, was significantly lower in the high-MTV tumor than in the low-MTV tumor. The TCA intermediate succinate level was significantly higher in the high-MTV tumor than in the low-MTV tumor. In contrast, the TCA intermediate fumarate level was significantly lower in the high-MTV tumor than in the low-MTV tumor. The levels of many amino acids were significantly higher in the high-MTV tumor than in the low-MTV tumor. CONCLUSIONS: Although preliminary, these results suggest that tumors with high FDG metabolism in CRC may obtain more energy by using a reverse reaction of the TCA cycle and amino-acid metabolism. However, further research is required to clarify this relationship.

A preliminary study of relationship among the degree of internal carotid artery stenosis, wall shear stress on MR angiography and 18F-FDG uptake on PET/CT.

BACKGROUND: This preliminary study was undertaken to evaluate relationship among the degree of internal carotid artery (ICA) stenosis, wall shear stress (WSS) by computational fluid dynamics (CFD) on magnetic resonance angiography (MRA) and 18F-FDG uptake of ICA on PET/CT. METHODS: A total of 40 carotid arteries in 20 patients with carotid atherosclerotic disease were examined with MRA and 18F-FDG PET/CT. Atherosclerotic risk factors were assessed in all patients. Degree of ICA stenosis was calculated according to NASCET method. CFD analysis was performed and maximum WSS (WSSmax) was measured. 18F-FDG uptake in ICA was quantified using maximum target-to-blood pool ratio (TBRmax). RESULTS: Atherosclerotic risk factors did not affect imaging findings. There were significant correlations between WSSmax and degree of ICA stenosis (ρ = .81, P < .001), WSSmax and TBRmax (ρ = .64, P < .001), and TBRmax and degree of ICA stenosis (ρ = .50, P = .001). CONCLUSIONS: These preliminary results indicate that there may be significant correlations among the degree of ICA stenosis, WSSmax and TBRmax in patients with carotid artery stenosis.

FLT PET/CT and FDG PET/CT of Skeletal Muscle Sarcoidosis.

Online supplemental material is available for this article.

Texture Indices of 18F-FDG PET/CT for Differentiating Squamous Cell Carcinoma and Non-Hodgkin's Lymphoma of the Oropharynx.

We assessed the role of 18F-FDG PET/CT texture indices for the differentiation of squamous cell carcinoma (SCC) and non-Hodgkin's lymphoma (NHL) in the oropharynx. 18F-FDG PET/CT data for 27 patients with SCC and 25 patients with NHL in the oropharynx were investigated. The maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and six texture indices (homogeneity, entropy, short-run emphasis, long-run emphasis, low gray-level zone emphasis [LGZE], and high graylevel zone emphasis [HGZE]) were derived from PET images. PET/CT parameters of the SCC patients were compared with those of the NHL patients. The diagnostic accuracy of the indices for differentiating SCC from NHL was calculated by a receiver operating characteristic curve analysis. 18F-FDG uptake in the oropharynx was observed in all of the patients. The SUVmax, MTV, and TLG did not differ significantly between the SCC and NHL groups, but two of the six texture indices (LGZE [p=0.004] and HGZE [p=0.03]) showed significant differences between the groups. LGZE was the best discriminative index for the differentiation of SCC and NHL (55.6% sensitivity, 88.0% specificity). The LGZE and HGZE texture indices derived from 18F-FDG PET/CT images may be useful in differentiating SCC and NHL in the oropharynx.

Myocarditis with high 18F-FDG uptake and no 18F-FLT uptake.

We present a case of myocarditis with increased 18F-FDG uptake and no 18F-fluorothymidine (FLT) uptake.