Texture Features of 18F-Fluorodeoxyglucose Positron Emission Tomography for Predicting Programmed Death-Ligand-1 Levels in Non-Small Cell Lung Cancer.

Background: Identifying programmed death-ligand-1 (PD-L1) expression is crucial for optimizing treatment strategies involving immune checkpoint inhibitors. However, the role of intratumoral metabolic heterogeneity specifically derived from 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) images in predicting PD-L1 expression in patients with newly diagnosed non-small cell lung cancer (NSCLC) remains unexplored. Here, we investigated the association between FDG PET texture features and PD-L1 expression by retrospectively analyzing the data of patients newly diagnosed with NSCLC who underwent FDG PET/CT scans and PD-L1 immunohistochemical staining before treatment. Methods: Patients were categorized based on their tumor proportion scores (TPSs) into negative-, low-, and high-PD-L1 expression groups. We computed the maximum standardized uptake value and 31 texture features for the primary tumor from PET images and compared differences in parameters among the groups. Results: Of the 83 patients, 12, 45, and 26 were assigned to the negative-, low-, and high-PD-L1 expression groups, respectively. Six specific texture features (low gray-level run emphasis, short-run low gray-level emphasis, long-run high gray-level emphasis, low gray-level zone emphasis, high gray-level zone emphasis, and short-zone low gray-level emphasis) helped distinguish among all possible combinations. Conclusions: Our findings revealed that FDG PET texture features are potential imaging biomarkers for predicting PD-L1 expression in patients newly diagnosed with NSCLC.

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.

FDG PET texture indices as imaging biomarkers for epidermal growth factor receptor mutation status in lung adenocarcinoma.

Identifying the epidermal growth factor receptor (EGFR) mutation status is important for the optimal treatment of patients with EGFR mutations. We investigated the relationship between 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) texture indices and EGFR mutation status in patients with newly diagnosed lung adenocarcinoma. We retrospectively analyzed data of patients with newly diagnosed lung adenocarcinoma who underwent pretreatment FDG PET/computed tomography and EGFR mutation testing between August 2014 and November 2020. Patients were divided into mutated EGFR and wild-type EGFR groups. The maximum standardized uptake value (SUVmax) and 31 texture indices for the primary tumor were calculated from PET images and compared between the two groups. Of the 66 patients included, 22 had mutated EGFR and 44 had wild-type EGFR. The SUVmax did not significantly differ between the two groups. Among the 31 evaluated texture indices, the following five showed a statistically significant difference between the groups: correlation (P = 0.003), gray-level nonuniformity for run (P = 0.042), run length nonuniformity (P = 0.02), coarseness (P = 0.006), and gray-level nonuniformity for zone (P = 0.04). Based on the preliminary results of this study in a small patient population, FDG PET texture indices may be potential imaging biomarkers for the EGFR mutation status in patients with newly diagnosed lung adenocarcinoma.

Feasibility of whole-body 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography angiography using continuous bed motion in patients with vascular disease: a pilot study.

OBJECTIVE: Positron emission tomography (PET) angiography is a promising PET imaging method for vessel evaluation. With advances in PET technologies, PET angiography of the whole body is now possible using continuous bed motion (CBM) mode. This study aimed to evaluate the image quality for depicting the aorta and main branches and the diagnostic performance of whole-body PET angiography in patients with vascular disease. METHODS: We retrospectively identified 12 consecutive patients who underwent whole-body 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) PET angiography in CBM mode. Whole-body PET angiography was performed between 20 and 45 s after administering [18F]FDG using CBM from the neck to the pelvis. The visibility of whole-body PET angiography was assessed for the 24 segments in three regions per patient using a 4-point grading scale (1, unacceptable; 2, poor; 3, good; 4, excellent), and grades 3 and 4 were considered diagnostic. The diagnostic accuracy of whole-body PET angiography for detecting vascular abnormalities was calculated using contrast-enhanced CT as a reference standard. RESULTS: We evaluated 285 segments from 12 patients, and overall, 170/285 segments (60%) were considered diagnostic throughout the whole body, including 96/117 (82%), 22/72 (31%), and 52/96 (54%) segments in the neck-to-chest region, abdominal region, and pelvic region, respectively. The sensitivity, specificity, and accuracy of whole-body PET angiography for detecting vascular abnormalities were 75.9%, 98.8%, and 96.5%, respectively. CONCLUSIONS: Whole-body PET angiography showed a better image quality for the neck-to-chest and pelvic regions in this setting, although it provided limited information on the vessels in the abdominal region.

[18F] FDG uptake in patients with spondyloarthritis: correlation with serum inflammatory biomarker levels.

BACKGROUND: We aimed to evaluate the correlation between 2-deoxy-2-[18F]fluoro-D-glucose (FDG) uptake and disease activity assessed by serum inflammatory biomarker levels in patients with spondyloarthritis (SpA). METHODS: A total of 36 SpA patients (24 untreated and 12 treated) were examined using FDG positron emission tomography (PET)/computed tomography and classified into axial SpA (axSpA) and peripheral SpA (pSpA). FDG uptake was evaluated in 23 regions of the body and scored as follows: 0 = less than liver uptake; 1 = more than or equal to liver uptake; and 2 = more than or equal to twice liver uptake. A score of 1 or 2 was considered positive. The number of positive regions and the total score were counted in each patient. The maximum standardized uptake value (SUVmax) was calculated for each region, and maximum SUVmax (MaxSUVmax) was used as a representative value. Correlation of PET findings with serum inflammatory biomarker levels, including C-reactive protein (CRP), erythrocyte sedimentation rate, and matrix metalloproteinase 3 (MMP-3), was analyzed. RESULTS: All but two patients had at least one positive lesion. PET indices correlated significantly with most of the serum inflammatory biomarker levels in untreated SpA, but not in treated SpA. Further, MaxSUVmax, number of positive regions, and total score correlated significantly with CRP (all P values < 0.001), and the number of positive regions (P = 0.012) and total score (P = 0.007) correlated significantly with MMP-3 in untreated pSpA. PET indices did not correlate with any serum inflammatory biomarker level in untreated axSpA. CONCLUSION: FDG uptake in untreated pSpA correlated significantly with serum inflammatory biomarker levels.

Unified Approach toward Syntheses of Juglomycins and Their Derivatives.

A unified and common intermediate strategy for syntheses of juglomycins and their derivatives is reported. The use of a 1,4-dimethoxynaphthalene derivative as a key intermediate enabled easy access to various juglomycin derivatives. In this study, juglomycins A-D, juglomycin C amide, khatmiamycin and its 4-epimer, and the structure proposed for juglomycin Z were synthesized from this intermediate. The absolute configuration of natural khatmiamycin has been established to be 3R,4R through our synthesis. Unfortunately, the spectroscopic data for synthetic juglomycin Z were not consistent with the data reported for the natural one, strongly suggesting a structural misassignment.

The homologous Arabidopsis MRS2/MGT/CorA-type Mg2+ channels, AtMRS2-10 and AtMRS2-1 exhibit different aluminum transport activity.

Magnesium (Mg2+) plays a critical role in many physiological processes. The AtMRS2/MGT family, which consists of nine Arabidopsis genes (and two pseudo-genes) belongs to a eukaryotic subset of the CorA superfamily of divalent cation transporters. AtMRS2-10 and AtMRS2-1 possess the signature GlyMetAsn sequence conserved in the CorA superfamily; however, they have low sequence conservation with CorA. Direct measurement using the fluorescent dye mag-fura-2 revealed that reconstituted AtMRS2-10 and AtMRS2-1 mediated rapid Mg2+ uptake into proteoliposomes. The rapid Mg2+ uptake through AtMRS2-10 was inhibited by aluminum. An assay using the Al-sensitive dye morin indicated Al uptake into the proteoliposomes through AtMRS2-10. AtMRS2-10 also exhibited Ni2+ transport activity but almost no Co2+ transport activity. The rapid Mg2+ uptake through AtMRS2-1 was not inhibited by aluminum. Al uptake into the proteoliposomes through AtMRS2-1 was not observed. The functional complementation assay in Escherichia coli strain TM2 showed that AtMRS2-1 was capable of mediating Mg2+ uptake. Heterologous expression using the E. coli mutant cells also showed that the E. coli cells expressing AtMRS2-1 was more resistant to aluminum than the E. coli cells expressing AtMRS2-10. The results suggested that AtMRS2-10 transported Al into the E. coli cells, and then the transported Al inhibited the growth of E. coli. AtMRS2-1 has been localized to the Arabidopsis tonoplast, indicating that AtMRS2-1 is exposed to much higher concentration of aluminum than AtMRS2-10. Under the conditions, it may be required that the Mg2+ transport of AtMRS2-1 is insensitive to Al inhibition, and AtMRS2-1 is impermeable to Al.