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Visceral adipose tissue (VAT) dysfunction has been recently recognized as a potential contributor to the development of Alzheimer's disease (AD). This study aimed to explore the relationship between VAT metabolism and cerebral glucose metabolism in patients with cognitive impairment. This cross-sectional prospective study included 54 patients who underwent 18 F-fluorodeoxyglucose ( 18 F-FDG) brain and torso positron emission tomography/computed tomography (PET/CT), and neuropsychological evaluations. VAT metabolism was measured by 18 F-FDG torso PET/CT, and cerebral glucose metabolism was measured using 18 F-FDG brain PET/CT. A voxel-based analysis revealed that the high-VAT-metabolism group exhibited a significantly lower cerebral glucose metabolism in AD-signature regions such as the parietal and temporal cortices. In the volume-of-interest analysis, multiple linear regression analyses with adjustment for age, sex, and white matter hyperintensity volume revealed that VAT metabolism was negatively associated with cerebral glucose metabolism in AD-signature regions. In addition, higher VAT metabolism was correlated with poorer outcomes on cognitive assessments, including the Korean Boston Naming Test, Rey Complex Figure Test immediate recall, and the Controlled Oral Word Association Test. In conclusion, our study revealed significant relationships among VAT metabolism, cerebral glucose metabolism, and cognitive function. This suggests that VAT dysfunction actively contributes to the neurodegenerative processes characteristic of AD, making VAT dysfunction targeting a novel AD therapy approach.

Objective: We aimed to evaluate whether the degree of F-18 fluorodeoxyglucose (FDG) uptake in the lungs is associated with an increased risk of lung cancer and to develop lung cancer risk prediction models using metabolic parameters on F-18 FDG positron emission tomography (PET)., Methods: We retrospectively included 795 healthy individuals who underwent F-18 FDG PET/CT scans for a health check-up. Individuals who developed lung cancer within 5 years of the PET/CT scan were classified into the lung cancer group (n = 136); those who did not were classified into the control group (n = 659). The healthy individuals were then randomly assigned to either the training (n = 585) or validation sets (n = 210). Clinical factors including age, sex, body mass index (BMI), and smoking history were collected. The standardized uptake value ratio (SUVR) and metabolic heterogeneity (MH) index were obtained for the bilateral lungs. Logistic regression models including clinical factors, SUVR, and MH index were generated to quantify the probability of lung cancer development using a training set. The prediction models were validated using a validation set., Results: The lung SUVR and lung MH index in the lung cancer group were significantly higher than in the control group (p < 0.001 and p < 0.001, respectively). In the combined prediction model 1, age, sex, BMI, smoking history, and lung SUVR were significantly associated with lung cancer development (age: OR 1.07, p < 0.001; male: OR 2.08, p = 0.015; BMI: OR 0.93, p = 0.057; current or past smoker: OR 5.60, p < 0.001; lung SUVR: OR 1.13, p < 0.001). In the combined prediction model 2, age, sex, BMI, smoking history, and lung MH index showed a significant association with lung cancer development (age: OR 1.06, p < 0.001; male: OR 1.87, p = 0.045; BMI: OR 0.93, p = 0.010; current or past smoker: OR 4.78, p < 0.001; lung MH index: OR 1.33, p < 0.001). In the validation data, combined prediction models 1 and 2 exhibited very good discrimination [area under the receiver operator curve (AUC): 0.867 and 0.901, respectively]., Conclusions: The metabolic parameters on F-18 FDG PET are related to an increased risk of lung cancer. Metabolic parameters can be used as biomarkers to provide information independent of the clinical parameters, related to lung cancer risk., (© 2023. The Author(s) under exclusive licence to The Japanese Society of Nuclear Medicine.)

We aimed to investigate the prognostic value of the metabolic parameters of 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in classical rectal adenocarcinoma (CRAC). We retrospectively reviewed 149 patients with CRAC who underwent preoperative 18 F-FDG PET/CT at initial diagnosis followed by curative surgical resection. 18 F-FDG PET/CT metabolic parameters including maximum standardized uptake value (SUVmax), metabolic tumour volume (MTV), and total lesion glycolysis (TLG) for disease-free survival (DFS) and overall survival (OS) were evaluated for prognostic significance by univariate and multivariate analyses, along with conventional risk factors including pathologic T (pT) stage, lymph node (LN) metastasis, lymphovascular invasion (LVI), perineural invasion (PNI), and preoperative carcinoembryonic antigen (CEA) level. On univariate analysis, high pT stage, positive LN metastasis, LVI, PNI, MTV, and TLG were significant prognostic factors affecting DFS (all P < 0.05), while CEA level, high pT stage, positive LN metastasis, LVI, PNI, MTV, and TLG affected OS (all P < 0.05). On multivariate analysis, positive LN metastasis, LVI, MTV, and TLG were independent prognostic factors affecting DFS (all P < 0.05), while CEA level, positive LN metastasis, and MTV affected OS (all P < 0.05). Thus, the volume-based metabolic parameters from preoperative 18 F-FDG PET/CT scans are independent prognostic factors in patients with CRAC.

Objective: The aim of this study was to investigate the prognostic value of the maximum standardized uptake value (SUV max ) measured while restaging with F-18 fluorodeoxyglucose ( 18 F-FDG) positron emission tomography/computed tomography (PET/CT) to predict the 3-year post-recurrence survival (PRS) in patients with recurrent gastric cancer after curative surgical resection., Materials and Methods: In total, 47 patients with recurrent gastric cancer after curative resection who underwent restaging with 18 F-FDG PET/CT were included. For the semiquantitative analysis, SUV max was measured over the visually discernable 18 F-FDG-avid recurrent lesions. Cox proportional-hazards regression models were used to predict the 3-year PRS. Differences in 3-year PRS were assessed with the Kaplan-Meier analysis., Results: Thirty-nine of the 47 patients (83%) expired within 3 years after recurrence in the median follow-up period of 30.3 months. In the multivariate analysis, SUV max ( p = 0.012), weight loss ( p = 0.025), and neutrophil count ( p = 0.006) were significant prognostic factors for 3-year PRS. The Kaplan-Meier curves demonstrated significantly poor 3-year PRS in patients with SUV max > 5.1 than in those with SUV max ≤ 5.1 (3-year PRS rate, 3.5% vs. 38.9%, p < 0.001)., Conclusion: High SUV max on restaging with 18 F-FDG PET/CT is a poor prognostic factor for 3-year PRS. It may strengthen the role of 18 F-FDG PET/CT in further stratifying the prognosis of recurrent gastric cancer., Competing Interests: The authors have no potential conflicts of interest to disclose., (Copyright © 2020 The Korean Society of Radiology.)

[ 18 F]Fluorodeoxyglucose ([ 18 F]FDG) Positron emission tomography/computed tomography (PET/CT) is commonly used for rectal cancer staging, but improved diagnostic methods for nodal metastases are needed. We aimed to evaluate whether the combination model of the metabolic tumor volume of primary tumor (T&#95;MTV) and maximum standardized uptake value of lymph node (N&#95;SUVmax) on pretreatment [ 18 F]FDG PET/CT could improve nodal metastases prediction in rectal cancer. We enrolled a total of 166 rectal cancer patients who underwent pretreatment [ 18 F]FDG PET/CT and surgical resection without neoadjuvant treatment between January 2009 and August 2016. Visual and semiquantitative PET/CT parameters were obtained. Associations between clinicopathological, PET/CT-derived variables and nodal metastases were evaluated by logistic regression analysis. Nodal metastases were confirmed histologically in 68 of the 166 patients (41%). Uni- and multivariate analyses demonstrated T&#95;MTV and N&#95;SUVmax were independent predictive factors for nodal metastases. The c-statistics of the combination model was 0.806 (Standard Error, 0.034; 95% Confidence Interval, 0.737-0.863), which showed significant improvement compared to T&#95;MTV (0.698, P = 0.0002) or N&#95;SUVmax (0.720, P = 0.0008) alone. T&#95;MTV and N&#95;SUVmax are independently correlated with nodal metastases. Furthermore, the combination model showed improved performance for risk prediction; thus, [ 18 F]FDG PET/CT might have a role in rectal cancer staging and treatment planning.

A 77-year-old man with anorexia and weight loss for 6 months received a diagnosis of gastric cancer by endoscopy and referred for F-FDG PET/CT for initial staging. F-FDG PET/CT showed multiple foci of increased FDG uptake with diffuse wall thickening and multiple diverticula. The differential diagnoses were peritoneal seeding and multiple diverticulitis. The patient underwent curative total gastrectomy, and the lesion was diagnosed as poorly differentiated adenocarcinoma by histological examination. He underwent anterior resection of the sigmoid colon for exploration. The nodular lesions of the sigmoid colon were diagnosed by histopathologic examination as chronic diverticulitis caused by a parasitic infection.

Background: This study assessed whether primary tumor maximum standardized uptake value (pSUV max ) measured by 18 F-fluoro-2-deoxy-D-glucose ( 18 F-FDG) positron emission tomography/computed tomography (PET/CT) could improve the prediction of axillary lymph node (ALN) metastasis in invasive ductal breast cancer (IDC)., Methods: In this study, 128 IDC patients who underwent pretreatment 18 F-FDG PET/CT and surgical resection of primary tumor with sentinel lymph node biopsy, ALN dissection, or both were analyzed. All the patients were classified as five molecular subtypes. The optimal cutoff values of pSUVmax for all the patients and each molecular subtype for the prediction of ALN metastasis were determined using receiver operating characteristic (ROC) analysis. Furthermore, the prognostic accuracy of ALN metastasis was assessed using c-statistics., Results: The findings showed ALN metastasis in 52 patients (40.6%). The 18 F-FDG PET/CT procedure had a sensitivity of 48.1% and a specificity of 94.7% for ALN metastasis. In the ROC analysis of pSUVmax for ALN metastasis, the optimal cutoff value was 3.9 for all the patients, 2.8 for the luminal A subtype, 3.3 for the luminal B (human epidermal growth factor receptor 2 [HER2]-negative) subtype, 5.3 for the luminal B (HER2-positive) subtype, 12.7 for the HER2-positive subtype, and 11.5 for the triple-negative subtype. A predictive ALN metastasis model using nodal 18 F-FDG uptake finding gave a c-statistic of 0.714, and a model combination of nodal 18 F-FDG uptake finding with pSUV max of all the patients gave a c-statistic of 0.736 (P = 0.3926). However, the combination of nodal the 18 F-FDG uptake finding with the pSUV max of each molecular subtype gave a c-statistic of 0.791 (P = 0.0047)., Conclusions: Combining the pSUV max of each molecular subtype with the nodal 18 F-FDG uptake finding can improve the prediction of ALN metastasis in IDC.

Objective: Because positron emission tomography/computed tomography (PET/CT) using fluorine-18-fluorodeoxyglucose ( 18 F-FDG) can be used to visualize inflammation of the musculoskeletal system, it may help elucidate the pathophysiology of frozen shoulder (FS). The purpose of this study was to characterize the uptake pattern on 18 F-FDG PET/CT in patients with idiopathic FS and to determine if there is a correlation between its metabolic parameters and clinical findings., Methods: 18 F-FDG PET/CT was conducted to 35 patients with unilateral idiopathic FS. Clinical data including pain, functional scores, and passive range of motion (ROM) were collected. Maximum standardized uptake values (SUVmax) were measured at the four regions of interest (ROIs): rotator interval (RI), anterior joint capsule (AJC), axillary recess (AR), and posterior joint capsule (PJC) from the attenuation-corrected axial images., Results: Mean SUVmax values for four ROIs of the affected shoulder were significantly higher than those of the unaffected shoulder. Mean SUVmax values of RI and AR were significantly higher than those of AJC and PJC and mean SUVmax of AJC was significantly higher than that of PJC in the affected side. Three recognizable patterns of increased uptake were noted: (1) AR dominant type (15 patients); (2) RI dominant type (9 patients); (3) both RI and AR dominant type (11 patients). The SUVmax of AR showed negative correlation with abduction and forward flexion. The SUVmax of RI showed negative correlation with external rotation and internal rotation. The SUVmax of AJC showed negative correlation with all ROMs. However, there was no significant correlation between the SUVmax of PJC and any ROM., Conclusion: Our study demonstrates that the anterior-inferior capsular portion, including RI and AR, is the main pathologic site of idiopathic FS and reveals significant correlations between ROM and metabolic parameters on 18 F-FDG PET/CT. These results imply that AR and RI lesions are related to elevational limitations and rotational limitations, respectively.

Preoperative screening for synchronous colorectal neoplasia (CRN) has been recommended in patients with gastric cancer because patients with gastric cancer are at increased risk for synchronous CRN. The aim of this study was to investigate the diagnostic accuracy of F-fluorodeoxyglucose (F-FDG) positron emission tomography/computed tomography (PET/CT) for detecting synchronous advanced CRN in patients with gastric cancer.A total of 256 patients who underwent colonoscopy and F-FDG PET/CT for preoperative staging were enrolled in this study. The diagnosis of focal colonic F-FDG uptake on F-FDG PET/CT image was made based on histopathologic results from the colonoscopic biopsy. The F-FDG PET/CT result was considered as true positive for advanced CRN when focal F-FDG uptake matched colorectal carcinoma or adenoma with high-grade dysplasia in the same location on colonoscopy.Synchronous advanced CRN was detected in 21 of the 256 patients (4.7%). Sensitivity, specificity, and accuracy of F-FDG PET/CT were 76.2%, 96.2%, and 94.5%. The size of CRN with a true positive result was significantly larger than that with a false negative result.F-FDG PET/CT demonstrated high diagnostic accuracy for detecting synchronous advanced CRN in patients with gastric cancer. Colonoscopy is recommended as the next diagnostic step for further evaluation of a positive F-FDG PET/CT result in patients with gastric cancer., Competing Interests: The authors have no conflicts of interest to disclose.

This study assessed whether preoperative maximum standardized uptake value (SUVmax) of metastatic lymph nodes (LNs) measured by F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (F-FDG PET/CT) could improve the prediction of prognosis in gastric cancer.One hundred fifty-one patients with gastric cancer and pathologically confirmed LN involvement who had undergone preoperative F-FDG PET/CT prior to curative surgical resection were retrospectively enrolled. To obtain nodal SUVmax, a transaxial image representing the highest F-FDG uptake was carefully selected, and a region of interest was manually drawn on the highest F-FDG accumulating LN. Conventional prognostic parameters and PET findings (primary tumor and nodal SUVmax) were analyzed for prediction of recurrence-free survival (RFS) and overall survival (OS). Furthermore, prognostic accuracy of survival models was assessed using c-statistics.Of the 151 patients, 38 (25%) experienced recurrence and 34 (23%) died during follow-up (median follow-up, 48 months; range, 5-74 months). Twenty-seven patients (18%) showed positive F-FDG nodal uptake (range, 2.0-22.6). In these 27 patients, a receiver-operating characteristic curve demonstrated a nodal SUVmax of 2.8 to be the optimal cutoff for predicting RFS and OS. The univariate and multivariate analyses showed that nodal SUVmax (hazard ratio [HR] = 2.71, P < 0.0001), pathologic N (pN) stage (HR = 2.58, P = 0.0058), and pathologic T (pT) stage (HR = 1.77, P = 0.0191) were independent prognostic factors for RFS. Also, nodal SUVmax (HR = 2.80, P < 0.0001) and pN stage (HR = 2.28, P = 0.0222) were independent prognostic factors for OS. A predictive survival model incorporating conventional risk factors (pT/pN stage) gave a c-statistic of 0.833 for RFS and 0.827 for OS, whereas a model combination of nodal SUVmax with pT/pN stage gave a c-statistic of 0.871 for RFS (P = 0.0355) and 0.877 for OS (P = 0.0313).Nodal SUVmax measured by preoperative F-FDG PET/CT is an independent prognostic factor for RFS and OS. Combining nodal SUVmax with pT/pN staging can improve survival prediction precision in patients with gastric cancer.

We describe the case of a 78-year-old man presenting with abdominal pain and a weight loss of 5 kg over 2 months. Colonoscopy and abdominal CT suggested colon cancer of hepatic flexure. F-FDG PET/CT scan showed moderate FDG uptake lesion at the hepatic flexure colon and multiple foci of FDG accumulation in the liver. These were considered as colon cancer with multiple hepatic metastases. However, the pathologic finding of colonoscopic biopsy and CT-guided liver biopsy showed only eosinophilic infiltration and no evidence of malignancy.

Purpose: The study aimed to evaluate the efficacy of PET/CT in detecting peritoneal carcinomatosis in patients with ovarian cancer and to compare the diagnostic accuracy of FDG PET/CT with that of enhanced abdominal CT., Methods: The medical records of 46 consecutive patients with ovarian cancer were reviewed, and the presence of peritoneal tumor on (18)F-FDG PET/CT and enhanced abdominal CT scans was also assessed. Imaging results were compared with the pathologic findings obtained by surgery., Results: Pathologic results were positive for peritoneal carcinomatosis in 26 patients and negative in 20 patients. PET/CT correctly detected 25 of 26 patients with peritoneal carcinomatosis and enhanced abdominal CT correctly detected 23 of 26 patients. Sensitivity and specificity for the diagnosis of peritoneal carcinomatosis were 96.2% and 90%, respectively, for PET/CT and 88.5% and 65%, respectively, for enhanced abdominal CT. The accuracy of PET/CT was statistically higher than that of enhanced abdominal CT (93.5% vs 78.3%, P = 0.039). Four distinctly abnormal PET/CT findings of single nodular, multiple nodular, diffuse, and mixed FDG uptakes were identified and corresponded to pathologic findings., Conclusions: (18)F-FDG PET/CT imaging is efficient in the diagnosis of peritoneal carcinomatosis and its performance is superior to that of enhanced abdominal CT.

We describe the ¹⁸F-FDG PET/CT findings of 2 simultaneous metastatic gastric cancers to the colon and spleen with quite different FDG avidities. Longitudinal and weak FDG uptake was observed in the descending colon; therefore, it could not be distinguished from nonpathological functional uptake of normal colon. Meanwhile, the splenic mass showed intense uptake. Contrast-enhanced CT revealed a segmental wall thickening of the descending colon as well as a hypoattenuating splenic mass suggesting metastases. Splenectomy and left hemicolectomy were performed. Histological diagnosis disclosed metastatic gastric cancer. The differential diagnoses and review of the literature are presented.

A 38-year-old man with a history of renal transplantation presented with a 3-month history of bilateral neck swelling. Ultrasonography of the neck showed multiple enlarged lymph nodes at the bilateral neck. Histologic examination of a specimen from an excisional biopsy at right level II cervical lymph node revealed polymorphic posttransplant lymphoproliferative disorder. F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography scan was performed for further evaluation. The scan revealed marked enlargement and intense hypermetabolism of the lymph nodes along the bilateral cervical lymph node chains (Fig. 1). Several reports have described that diverse infectious or inflammatory disorders and malignant diseases show various degree of FDG uptake of cervical lymph nodes. This case illustrates that the possibility of posttransplant lymphoproliferative disorder should be considered in renal transplant patients with increased FDG uptake of cervical lymph nodes on F-18 FDG positron emission tomography/computed tomography scan.

An 83-year-old man was referred with a right lung mass on dynamic chest computed tomography (CT). F-18 fluoro-deoxy-glucose positron emission tomography (FDG PET)/CT showed intense FDG uptake in the right lung mass and bilateral hypermetabolic mediastinal lymph nodes. CT-guided biopsy of the right lung mass revealed metastatic adenocarcinoma from the colon, but a colon cancer lesion was not detected by dynamic abdominal CT and colonoscopy.

Twelve parotid incidentalomas in 10 consecutive subjects (nine with a known malignancy elsewhere and one presumptively healthy subject) identified by combined 18F-fluorodeoxyglucose whole-body positron emission tomography and computed tomography (18F-FDG PET/CT) were investigated, with the aim of calculating maximum standardized uptake value (SUV(max)) of each FDG-avid focus, and identifying corresponding sonographic and pathologic findings. The results of ultrasound-guided fine-needle aspiration biopsy (FNAB) (n = 9) and core-needle biopsy (CNB) (n = 3) were Warthin tumor in 10 cases, and pleomorphic adenoma and chronic inflammation in one each. SUV(max) was 7.0-21.0 g/mL (average 13.7 g/mL) for Warthin tumor, 6.8 g/mL for pleomorphic adenoma, and 7.3 g/mL for chronic inflammation. Each FDG-avid focus corresponded to ovoid (n = 11) or lobulated (n = 1) hypoechoic mass on grayscale ultrasonography (US) and hypervascular mass, except one with chronic inflammation, on power Doppler (PD) US. Parotid incidentaloma identified by 18F-FDG PET/CT during workup of various malignancies elsewhere does not necessarily signify primary or metastatic malignancy, but indicates a high likelihood of benign lesions, particularly Warthin tumor. Such lesions should be evaluated thoroughly by US and ultrasound-guided FNAB or CNB if parotid disease would change the patient's treatment plan.

Background: Chronic cerebral hypoperfusion (CCH) is known to induce Alzheimer's disease (AD) pathology, but its mechanism remains unclear. The purpose of this study was to identify the cerebral regions that are affected by CCH, and to evaluate the development of AD pathology in a rat model of CCH. Methods: A rat model of CCH was established by bilaterally ligating the common carotid arteries in adult male rats (CCH group). The identical operations were performed on sham rats without arteries ligation (control group). Regional cerebral glucose metabolism was evaluated at 1 and 3 months after bilateral CCA ligation using positron emission tomography with F-18 fluorodeoxyglucose. The expression levels of amyloid β40 (Aβ40), amyloid β42 (Aβ42), and hyperphosphorylated tau were evaluated using western blots at 3 months after the ligation. Cognitive function was evaluated using the Y-maze test at 3 months after the ligation. Results: At 1 month after the ligation, cerebral glucose metabolism in the entorhinal, frontal association, motor, and somatosensory cortices were significantly decreased in the CCH group compared with those in the control group. At 3 months after the ligation, cerebral glucose metabolism was normalized in all regions except for the anterodorsal hippocampus, which was significantly decreased compared with that of the control group. The expression of Aβ42 and the Aβ42/40 ratio were significantly higher in the CCH group than those in the control group. The phosphorylated-tau levels of the hippocampus in the CCH group were significantly lower than those in the control group. Cognitive function was more impaired in the CCH group than that in the control group. Conclusion: Our findings suggest that CCH causes selective neurodegeneration of the anterodorsal hippocampus, which may be a trigger point for the development of AD pathology. [ABSTRACT FROM AUTHOR]

Cerebrovascular disease is a potential risk factor for Alzheimer's disease (AD). Although acute cerebral hypoperfusion causes neuronal necrosis and infarction, chronic cerebral hypoperfusion induces apoptosis in neurons, but its effects on the cognitive impairment are not clear. The purpose of this study was to evaluate the effects of chronic cerebral hypoperfusion on AD pathology and cerebral glucose metabolism. A model of chronic cerebral hypoperfusion was established by ligating the common carotid arteries bilaterally in adult male rats (CAL group). Sham-operated rats underwent the same procedures without artery ligation (control group). At 12 weeks after ligation, expression levels of amyloid-β (Aβ) and hyperphosphorylated tau (p-tau), as well as the regional cerebral glucose metabolism, were evaluated using Western blots and positron emission tomography with fluorine-18 fluorodeoxyglucose, respectively. The expression levels of Aβ in the frontal cortex and hippocampus and of p-tau in the temporal cortex were significantly higher in the CAL group than those in the control group. The cerebral glucose metabolism of the amygdala, entorhinal cortex, and hippocampus was significantly decreased in the CAL group compared to that in the control. These results suggest that chronic cerebral hypoperfusion can induce AD pathology and may play a significant role in AD development. [ABSTRACT FROM AUTHOR]

We analyzed RNA sequencing in iCCA patients to evaluate gene expression signatures associated with FDG uptake patterns. Cell cycle, hypoxia and metabolism-related pathways were enriched in high SUVmax patients. Patients with high FDG uptake have enriched cell cycle, metabolism and hypoxic pathways, which may lead to a more rational targeted treatment approach. [Extracted from the article]