Stress-associated neurobiological activity is linked with acute plaque instability via enhanced macrophage activity: a prospective serial 18F-FDG-PET/CT imaging assessment.

AIMS: Emotional stress is associated with future cardiovascular events. However, the mechanistic linkage of brain emotional neural activity with acute plaque instability is not fully elucidated. We aimed to prospectively estimate the relationship between brain amygdalar activity (AmygA), arterial inflammation (AI), and macrophage haematopoiesis (HEMA) in acute myocardial infarction (AMI) as compared with controls. METHODS AND RESULTS: 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) imaging was performed within 45 days of the index episode in 62 patients (45 with AMI, mean 60.0 years, 84.4% male; 17 controls, mean 59.6 years, 76.4% male). In 10 patients of the AMI group, serial 18F-FDG-PET/CT imaging was performed after 6 months to estimate the temporal changes. The signals were compared using a customized 3D-rendered PET reconstruction. AmygA [target-to-background ratio (TBR), mean ± standard deviation: 0.65 ± 0.05 vs. 0.60 ± 0.05; P = 0.004], carotid AI (TBR: 2.04 ± 0.39 vs. 1.81 ± 0.25; P = 0.026), and HEMA (TBR: 2.60 ± 0.38 vs. 2.22 ± 0.28; P < 0.001) were significantly higher in AMI patients compared with controls. AmygA correlated significantly with those of the carotid artery (r = 0.350; P = 0.005), aorta (r = 0.471; P < 0.001), and bone marrow (r = 0.356; P = 0.005). Psychological stress scales (PHQ-9 and PSS-10) and AmygA assessed by PET/CT imaging correlated well (P < 0.001). Six-month after AMI, AmygA, carotid AI, and HEMA decreased to a level comparable with the controls. CONCLUSION: AmygA, AI, and HEMA were concordantly enhanced in patients with AMI, showing concurrent dynamic changes over time. These results raise the possibility that stress-associated neurobiological activity is linked with acute plaque instability via augmented macrophage activity and could be a potential therapeutic target for plaque inflammation in AMI.

The effects of cerebral amyloidopathy on regional glucose metabolism in older adults with depression and mild cognitive impairment while performing memory tasks.

Co-occurring depression and mild cognitive impairment (MCI) in older adults are important because they have a high risk of conversion to dementia. In the present study, task-related F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) was used to analyse older adults with concomitant depression and MCI. We recruited 20 older adults with simultaneous depression and MCI and 10 older adults with normal cognition (NC). The Verbal Paired Associates test and digit span test were used for the task-related FDG-PET. The 20 older adults with depression and MCI were classified into two groups based on the F-18 florbetaben PET results: depressed MCI patients with (LLD-MCI-A[+]; n = 11) and without amyloid accumulation (LLD-MCI-A[-]; n = 9). Reduced regional cerebral glucose metabolism (rCMglc) in the left superior frontal region was observed in the LLD-MCI-A(-) group compared with the NC group. Analyses of the NC and LLD-MCI-A(+) groups showed significantly decreased rCMglc in the right inferior parietal and left middle frontal regions in the LLD-MCI-A(+) group. rCMglc in the left precuneus was lower in the LLD-MCI-A(+) group than in the LLD-MCI-A(-) group. Significant correlations between the rCMglc in the right inferior parietal/left precuneus regions and memory task scores were observed based on correlation analyses of NC and LLD-MCI-A(+) groups. The findings in the present study indicate the presence of amyloid accumulation influences glucose metabolism in depressed elderly subjects with MCI while performing cognitive tasks. Task-related FDG-PET examinations may help differentiate MCI associated with depression from comorbid depression in patients with prodromal Alzheimer's disease.

Preoperative prediction of microvascular invasion of hepatocellular carcinoma using 18F-FDG PET/CT: a multicenter retrospective cohort study.

PURPOSE: The aim of this study was to assess the potential of tumor 18F-fluorodeoxyglucose (FDG) avidity as a preoperative imaging biomarker for the prediction of microvascular invasion (MVI) of hepatocellular carcinoma (HCC). METHODS: One hundred and fifty-eight patients diagnosed with Barcelona Clinic Liver Cancer stages 0 or A HCC (median age, 57 years; interquartile range, 50-64 years) who underwent 18F-FDG positron emission tomography with computed tomography (PET/CT) before curative surgery at seven university hospitals were included. Tumor FDG avidity was measured by tumor-to-normal liver standardized uptake value ratio (TLR) of the primary tumor on FDG PET/CT imaging. Logistic regression analysis was performed to identify significant parameters associated with MVI. The predictive performance of TLR and other clinical variables was assessed using receiver operating characteristic (ROC) curve analysis. RESULTS: MVI was present in 76 of 158 patients with HCCs (48.1%). Multivariable logistic regression analysis revealed that TLR, serum alpha-fetoprotein (AFP) level, and tumor size were significantly associated with the presence of MVI (P < 0.001). Multinodularity was not significantly associated with MVI (P = 0.563). The area under the ROC curve (AUC) for predicting the presence of MVI was best with TLR (AUC = 0.704), followed by tumor size (AUC = 0.685) and AFP (AUC = 0.670). We were able to build an improved prediction model combining TLR, tumor size, and AFP by using multivariable logistic regression modeling (AUC = 0.756). CONCLUSIONS: Tumor FDG avidity measured by TLR on FDG PET/CT is a preoperative imaging biomarker for the prediction of MVI in patients with HCC.

Correction to: a risk stratification model for nodal peripheral T-cell lymphomas based on the NCCN-IPI and posttreatment Deauville score.

Unfortunately, the original version of this article contained several errors made during final step of article production. In the results section (fourth sentence) of the Abstract, the incomplete sentence,", 31.4% in high-risk group and 4.7% in treatment failure group.

A risk stratification model for nodal peripheral T-cell lymphomas based on the NCCN-IPI and posttreatment Deauville score.

PURPOSE: The aim of this study was to establish a risk-stratification model integrating posttreatment metabolic response using the Deauville score and the pretreatment National Comprehensive Cancer Network-International Prognostic Index (NCCN-IPI) in nodal PTCLs. METHODS: We retrospectively analysed 326 patients with newly diagnosed nodal PTCLs between January 2005 and June 2016 and both baseline and posttreatment PET/CT data. The final model was validated using an independent prospective cohort of 79 patients. RESULTS: Posttreatment Deauville score (1/2, 3, and 4/5) and the NCCN-IPI (low, low-intermediate, high-intermediate, and high) were independently associated with progression-free survival: for the Deauville score, the hazard ratios (HRs) were 1.00 vs. 2.16 (95% CI 1.47-3.18) vs. 7.86 (5.66-10.92), P < 0.001; and for the NCCN-IPI, the HRs were 1.00 vs. 2.31 (95% CI 1.20-4.41) vs. 4.42 (2.36-8.26) vs. 7.09 (3.57-14.06), P < 0.001. Based on these results, we developed a simplified three-group risk model comprising a low-risk group (low or low-intermediate NCCN-IPI with a posttreatment Deauville score of 1 or 2, or low NCCN-IPI with a Deauville score of 3), a high-risk group (high or high-intermediate NCCN-IPI with a Deauville score of 1/2 or 3, or low-intermediate NCCN-IPI with a Deauville score of 3), and a treatment failure group (Deauville score 4 or 5). This model was significantly associated with progression-free survival (5-year, 70.3%, 31.4%, and 4.7%; P < 0.001) and overall survival (5-year, 82.1%, 45.5%, and 14.7%; P < 0.001). Similar associations were also observed in the independent validation cohort. CONCLUSION: The risk-stratification model integrating posttreatment Deauville score and pretreatment NCCN-IPI is a powerful tool for predicting treatment failure in patients with nodal PTCLs.

Prognostic value of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography in patients with Barcelona Clinic Liver Cancer stages 0 and A hepatocellular carcinomas: a multicenter retrospective cohort study.

PURPOSE: We evaluated the prognostic value of pretreatment (18)F-fluorodeoxyglucose positron emission tomography with computed tomography (FDG PET/CT) in patients with Barcelona Clinic Liver Cancer (BCLC) stage 0 or A hepatocellular carcinoma (HCC) who had received curative treatment or transarterial chemoembolization (TACE). METHODS: Between 2009 and 2010, 317 patients diagnosed with HCC at seven hospitals were enrolled. Among these, 195 patients underwent curative treatments including resection, liver transplantation, and radiofrequency ablation. TACE was performed in 122 patients. The tumor-to-normal liver standardized uptake value ratio (TLR) of the primary tumor was measured using pretreatment FDG PET/CT. The prognostic significance of TLR and other clinical variables was assessed using Cox regression models. Differences in the overall survival (OS) associated with TLR or other significant clinical factors were examined using the Kaplan-Meier method. RESULTS: Over a median follow-up period of 46 months, 77 patients died from cancer. In the curative cohort, higher TLR (≥2) was significantly associated with death (hazard ratio [HR] = 2.68; 95 % CI, 1.16-6.15; P = 0.020) in multivariable analysis. Patients with a higher TLR had significantly worse OS than patients with a lower TLR (5-year overall survival, 61 % vs. 79.4 %; P = 0.006). In the TACE cohort, the Model for End-Stage Liver Disease (MELD) score (≥8) was a significant independent prognostic factor for OS (HR = 3.34; 95 % CI, 1.49-7.48; P = 0.003), whereas TLR was not associated with OS. The Kaplan-Meier curves showed significantly poorer OS in patients with higher MELD scores (≥8) than in those with lower MELD scores (5-year survival rate, 33.1 % vs. 79.6 %; P < 0.001). CONCLUSIONS: Pretreatment TLR measured using FDG PET/CT was an independent prognostic factor for OS in patients with BCLC stage 0 or A HCC undergoing curative treatment. In contrast, underlying liver function appeared to be important in predicting the prognosis of patients undergoing TACE.

Gallium-68 neomannosylated human serum albumin-based PET/CT lymphoscintigraphy for sentinel lymph node mapping in non-small cell lung cancer.

PURPOSE: To develop imaging of lymphatics with resolution greater than that of lymphoscintigraphy using technetium-99 m neomannosyl human serum albumin ((99m)Tc-MSA), we developed a Gallium-68 ((68)Ga) MSA for positron emission tomography (PET). This study is the first clinical trial to evaluate the feasibility of sentinel node detection using this novel (68)Ga tracer for the management of non-small cell lung cancer. METHODS: We enrolled 34 patients (20 men, 14 women; mean age, 64.3 ± 10.4 years) who were candidates for lobectomy with mediastinal lymph node dissection for clinical stage I non-small cell lung cancer. (68)Ga-MSA was administered in one injection into the peritumoral region, and lymphoscintigraphy was performed by PET/CT just before surgery. All harvested lymph nodes were cut into 2 mm slices and were ultimately diagnosed using formalin-fixed and paraffin-embedded sections with hematoxylin and eosin staining. RESULTS: The sentinel nodes were well visualized by PET/CT imaging from 15 to 120 min, and especially within 60 min, after injection. In all patients (100 %), sentinel nodes could be identified on PET/CT. The number of sentinel nodes identified was 1.9 ± 0.9 (range 1-5) per patient. The maximum standardized uptake values were 2882.2 ± 2124.3 in the tumor and 82.5 ± 159.0 in the sentinel nodes. Eight of 34 patients (23.5 %) had metastases in 13 sentinel nodes. No false-negative sentinel nodes were detected in any of the eight patients with N1 or N2 disease (0 %). CONCLUSIONS: (68)Ga-MSA appears to be a promising tracer for sentinel node identification in non-small cell lung cancer.

Simultaneous Visualization of Lung Tumor and Intersegmental Plane during Pulmonary Segmentectomy by Intravenous Injection of Indocyanine Green.

Segmentectomy is a targeted surgical approach tailored for patients with compromised health and early-stage lung cancer. The key to successful segmentectomy lies in precisely identifying the tumor and intersegmental planes to ensure adequate resection margins. In this study, we aimed to enhance this process by simultaneously visualizing the tumor and intersegmental planes through the intravenous injection of indocyanine green (ICG) at different time points and doses. Lung tumors were detected by intravenous injection of ICG at a dose of 2 mg/kg 12 h before surgery in a rabbit model. Following the dissection of the pulmonary artery, vein, and bronchi of the target segment, 0.6 mg/kg of ICG was injected intravenously to detect the intersegmental plan. Fluorescent images of the lung tumors and segments were acquired, and the fluorescent signal was quantified using the signal-to-background ratio (SBR). Finally, a pilot study of this method was conducted in three patients with lung cancer. In a preclinical study, the SBR of the tumor (4.4 ± 0.1) and nontargeted segments (10.5 ± 0.8) were significantly higher than that of the targeted segment (1.6 ± 0.2) (targeted segment vs. nontarget segment, p < 0.0001; target segment vs. tumor, p < 0.01). Consistent with preclinical results, lung tumors and the intersegmental plane were successfully detected in patients with lung cancer. Consequently, adequate resection margins were identified during the surgery, and segmentectomy was successfully performed in patients with lung cancer. This study is the first to use intravenous ICG injections at different time points and doses to simultaneously detect lung cancer and intersegmental planes, thereby achieving segmentectomy for lung cancer.

Colon cancer: the 2023 Korean clinical practice guidelines for diagnosis and treatment.

Colorectal cancer is the third most common cancer in Korea and the third leading cause of death from cancer. Treatment outcomes for colon cancer are steadily improving due to national health screening programs with advances in diagnostic methods, surgical techniques, and therapeutic agents.. The Korea Colon Cancer Multidisciplinary (KCCM) Committee intends to provide professionals who treat colon cancer with the most up-to-date, evidence-based practice guidelines to improve outcomes and help them make decisions that reflect their patients' values and preferences. These guidelines have been established by consensus reached by the KCCM Guideline Committee based on a systematic literature review and evidence synthesis and by considering the national health insurance system in real clinical practice settings. Each recommendation is presented with a recommendation strength and level of evidence based on the consensus of the committee.

Prognostic value of textural features obtained from F-fluorodeoxyglucose (F-18 FDG) positron emission tomography/computed tomography (PET/CT) in patients with locally advanced cervical cancer undergoing concurrent chemoradiotherapy.

OBJECTIVE: To evaluate whether textural features obtained from F-18 FDG PET/CT offer clinical value that can predict the outcome of patients with locally advanced cervical cancer (LACC) receiving concurrent chemoradiotherapy (CCRT). METHODS: We reviewed the records of 68 patients with stage IIB-IVA LACC who underwent PET/CT before CCRT. Conventional metabolic parameters, shape indices, and textural features of the primary tumor were measured on PET/CT. A Cox regression model was used to examine the effects of variables on overall survival (OS) and progression-free survival (PFS). RESULTS: The patients included in this study were classified into two groups based on median value of PET/CT parameters. The high group of GLNU derived from GLRLM is only independent prognostic factor for PFS (HR 7.142; 95% CI 1.656-30.802; p = 0.008) and OS (HR 9,780; 95% CI 1.222-78.286; p = 0.031). In addition, GLNU derived from GLRLM (AUC 0.846, 95% CI 0.738-0.923) was the best predictor for recurrence among clinical prognostic factors and PET/CT parameters. CONCLUSION: Our results demonstrated that high GLNU from GLRLM on pretreatment F-18 FDG PET/CT images, were significant prognostic factors for recurrence and death in patients with LACC receiving CCRT.

Automatic Lung Cancer Segmentation in [18F]FDG PET/CT Using a Two-Stage Deep Learning Approach.

Purpose: Since accurate lung cancer segmentation is required to determine the functional volume of a tumor in [18F]FDG PET/CT, we propose a two-stage U-Net architecture to enhance the performance of lung cancer segmentation using [18F]FDG PET/CT. Methods: The whole-body [18F]FDG PET/CT scan data of 887 patients with lung cancer were retrospectively used for network training and evaluation. The ground-truth tumor volume of interest was drawn using the LifeX software. The dataset was randomly partitioned into training, validation, and test sets. Among the 887 PET/CT and VOI datasets, 730 were used to train the proposed models, 81 were used as the validation set, and the remaining 76 were used to evaluate the model. In Stage 1, the global U-net receives 3D PET/CT volume as input and extracts the preliminary tumor area, generating a 3D binary volume as output. In Stage 2, the regional U-net receives eight consecutive PET/CT slices around the slice selected by the Global U-net in Stage 1 and generates a 2D binary image as the output. Results: The proposed two-stage U-Net architecture outperformed the conventional one-stage 3D U-Net in primary lung cancer segmentation. The two-stage U-Net model successfully predicted the detailed margin of the tumors, which was determined by manually drawing spherical VOIs and applying an adaptive threshold. Quantitative analysis using the Dice similarity coefficient confirmed the advantages of the two-stage U-Net. Conclusion: The proposed method will be useful for reducing the time and effort required for accurate lung cancer segmentation in [18F]FDG PET/CT.

Identification of Metastatic Lymph Nodes Using Indocyanine Green Fluorescence Imaging.

Indocyanine green (ICG) has been used to detect several types of tumors; however, its ability to detect metastatic lymph nodes (LNs) remains unclear. Our goal was to determine the feasibility of ICG in detecting metastatic LNs. We established a mouse model and evaluated the potential of ICG. The feasibility of detecting metastatic LNs was also evaluated in patients with lung or esophageal cancer, detected with computed tomography (CT) or positron-emission tomography (PET)/CT, and scheduled to undergo surgical resection. Tumors and metastatic LNs were successfully detected in the mice. In the clinical study, the efficacy of ICG was evaluated in 15 tumors and fifty-four LNs with suspected metastasis or anatomically key regional LNs. All 15 tumors were successfully detected. Among the fifty-four LNs, eleven were pathologically confirmed to have metastasis; all eleven were detected in ICG fluorescence imaging, with five in CT and seven in PET/CT. Furthermore, thirty-four LNs with no signals were pathologically confirmed as nonmetastatic. Intravenous injection of ICG may be a useful tool to detect metastatic LNs and tumors. However, ICG is not a targeting agent, and its relatively low fluorescence makes it difficult to use to detect tumors in vivo. Therefore, further studies are needed to develop contrast agents and devices that produce increased fluorescence signals.

Independent effect of Aß burden on cognitive impairment in patients with small subcortical infarction.

BACKGROUND: The effect of amyloid-ß (Aß) on cognitive impairment in patients with small subcortical infarction remains controversial, although a growing body of evidence shows a substantial overlap between Alzheimer's disease (AD) and subcortical ischemic vascular dementia, another form of cerebral small vessel disease (cSVD). Therefore, we investigated the relationships between Aß positivity and the development of post-stroke cognitive impairment (PSCI) in patients with small subcortical infarction. METHODS: We prospectively recruited 37 patients aged ≥ 50 years, with first-ever small subcortical infarction, who underwent amyloid positron emission tomography, 3 months after stroke at Korea University Guro Hospital. We also enrolled CU participants matched for age and sex with stroke patients for comparison of Aß positivity. Patients were followed up at 3 and 12 months after the stroke to assess cognitive decline. Logistic and linear mixed-effect regression analyses were performed to identify the effect of Aß positivity on PSCI development and long-term cognitive trajectories. RESULTS: At 3 months after stroke, 12/37 (32.4%) patients developed PSCI, and 11/37 (29.7%) patients had Aß deposition. Aß positivity (odds ratio [OR] = 72.2, p = 0.024) was predictive of PSCI development regardless of cSVD burden. Aß positivity (ß = 0.846, p = 0.014) was also associated with poor cognitive trajectory, assessed by the Clinical Dementia Rating-Sum of Box, for 1 year after stroke. CONCLUSIONS: Our findings highlight that Aß positivity is an important predictor for PSCI development and cognitive decline over 1 year. Furthermore, our results provide evidence that anti-AD medications may be a strategy for preventing cognitive decline in patients with small subcortical infarctions.

Prognostic value of metabolic tumor volume measured by FDG-PET/CT in patients with cervical cancer.

OBJECTIVE: To determine if preoperative metabolic tumor volume (MTV) measured by integrated (18)F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (FDG-PET/CT) imaging has prognostic value in patients with cervical cancer treated primarily with radical hysterectomy. METHODS: Patients with FIGO stage IB to IIA cervical cancer were imaged with FDG-PET/CT before radical surgery. MTV was measured from attenuation-corrected FDG-PET/CT images using a standard uptake value (SUV)-based automated contouring program. We evaluated the relationship of MTV to disease-free survival (DFS). RESULTS: A total of 63 patients were included in the study. The cut-off value for predicting recurrence was determined using a receiver operating characteristic (ROC) curve. MTV in this study was found to be correlated with lymph node (LN) metastasis, parametrium (PM) involvement, FIGO stage, and SUV(max). In univariate analysis, MTV≥23.4 mL (HR 1.017, 95% confidence interval (CI) 1.005-1.029, P=0.004), SUV(max)≥9.5 (HR 5.198, 95% CI 1.076-25.118, P=0.04), LN metastasis (HR 12.338, 95% CI 1.541-98.813, P=0.018), PM involvement (HR 14.274, 95% CI 1.785-114.149, P=0.012), and lymphovascular space invasion (HR 8.871, 95% CI 1.104-71.261, P=0.04), were related to DFS. In multivariate analyses, age (HR 0.748, 95% CI 0.587-0.952, P=0.018) and MTV≥23.4 mL (HR 49.559, 95% CI 1.257-1953.399, P=0.037) were determined to be independent prognostic factors of DFS. CONCLUSION: Preoperative MTV is an independent prognostic factor for DFS in patients with cervical cancer treated by radical surgery.

Brain amyloid accumulation possibly exacerbates concurrent mild cognitive impairment with subthreshold depression in older adults: A 1-year follow-up study.

BACKGROUND: This study aimed to investigate the 1-year changes in neuropsychological test results in older adults with concomitant late-life depression (LLD) and mild cognitive impairment (MCI) according to the presence or absence of brain amyloidopathy. METHODS: All subjects underwent 18F-florbetaben-positron emission tomography and a standardized neuropsychological battery. The subjects were divided based on brain amyloidopathy and severity of depressive symptoms into the following groups: LLD-MCI-A(+), subthreshold depression (STD)-MCI-A(+), major depressive disorder (MDD)-MCI-A(+), LLD-MCI-A(-), STD-MCI-A(-), and MDD-MCI-A(-). After one year, follow-up neurocognitive tests were conducted. Fifty-nine participants completed both the baseline and 1-year follow-up neurocognitive tests. RESULTS: In the LLD-MCI-A(+) group, the word list recall and word list recognition scores decreased during the follow-up period. The STD-MCI-A(+) group also showed a significant decrease in word list recall score and the score/Z-score of word list recognition. On the other hand, the word list recall Z-score improved at the 1-year follow-up in the LLD-MCI-A(-) group. In particular, the MDD-MCI-A(-) group showed significant increases in word list memory score/Z-score and word list recall Z-score during the follow-up period. LIMITATIONS: Considering that AD progresses slowly, a longer follow-up period may be required. CONCLUSIONS: Our findings showed differences in the extent of change of neuropsychological test results depending on the severity of depressive symptoms and presence or absence of brain amyloidopathy. Our results suggest that clinicians might explore the underlying neuropathology when assessing older adults with concomitant depression and cognitive impairment, even if the symptoms of depression are not severe.

Comparison of High-Dose Rosuvastatin Versus Low-Dose Rosuvastatin Plus Ezetimibe on Carotid Atherosclerotic Plaque Inflammation in Patients with Acute Coronary Syndrome.

We compared the effects of ezetimibe/rosuvastatin 10/5 mg versus rosuvastatin 20 mg on carotid atherosclerotic plaque inflammation measured by 18FDG PET/CT. Fifty patients with acute coronary syndrome (ACS) were randomly assigned to the ezetimibe/rosuvastatin 10/5 mg and rosuvastatin 20 mg groups. The primary outcome was the percent change in the target-to-background ratio (TBR) of the index vessel in the most diseased segment (MDS), as assessed by 18FDG PET/CT at baseline and at 6 months. Forty-eight patients completed follow-up PET/CT. MDS TBR was - 6.2 ± 13.9% for patients in the ezetimibe/rosuvastatin group and - 10.8 ± 17.7% for those in the rosuvastatin group (difference, 4.6 percentage points; upper limitation of one-sided confidence interval = 13.8; p = 0.60 for noninferiority). In conclusion, combination therapy with ezetimibe 10 mg and rosuvastatin 5 mg compared with rosuvastatin 20 mg did not meet the criterion for non-inferiority for primary outcome, and the present study was not conclusive on whether the former was non-inferior to the latter. Graphical Abstract.

Recent Survey of Effective Doses of F-18 FDG Torso PET/CT in Korea and the Current Recommendations for CT Protocols of PET/CT.

PURPOSE: This study aimed to construct a database of the effective doses (ED) from F-18 fluorodeoxyglucose (FDG) torso positron emission tomography/computed tomography (PET/CT) in Korea to provide data that supports the reduction of the CT dose of PET/CT and optimization of PET/CT protocols in Korea. METHODS: We investigated data of ED and CT parameters of FDG PET/CT. The data were analyzed by body weight groups. RESULTS: A total of 31 hospitals participated in the survey (99 adults). The mean total EDs (± SD) were 8.77 ± 2.76, 10.93 ± 3.14, and 12.57 ± 3.79 mSv for the 55-, 70-, and 85-kg groups, respectively. The FDG EDs were 4.80 ± 0.98, 6.05 ± 1.15, and 6.89 ± 1.52 mSv, and the CT EDs were 4.00 ± 2.12, 4.88 ± 2.51, and 5.68 ± 2.89 mSv, respectively. Of the enrolled hospitals, 54.5% used ultra-low-dose CT protocols, and their CT ED was significantly lower than low-dose CT group in all groups (2.9 ± 1.0, 3.2 ± 1.1, and 3.3 ± 1.0 mSv vs. 6.6 ± 1.6, 7.2 ± 2.1, and 7.9 ± 2.2 mSv, all p < 0.001, respectively). In the ultra-low-dose CT group, the CT ED with the iterative reconstruction was significantly lower than that of CT without iterative reconstruction in the 55-kg group (2.4 ± 0.9 vs. 3.3 ± 0.9, p = 0.04). CONCLUSIONS: These results and current recommendations can be helpful for optimizing PET/CT diagnostic reference level (DRL) and reducing unnecessary PET/CT radiation exposure.

Clinical implications of circulating cell-free DNA quantification and metabolic tumor burden in advanced non-small cell lung cancer.

OBJECTIVES: This study unravels the significance of cell-free DNA (cfDNA) quantification as a promising measure of the biological behavior/aggressiveness of tumors. Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) measured by positron emission tomography/computed tomography scan enable a precise assessment of metabolic tumor burden. However, their clinical implications in identifying patients who need more aggressive treatment in advanced non-small cell lung cancer (NSCLC) are not fully understood. MATERIALS AND METHODS: In the current prospective trial, we analyzed 101 newly diagnosed advanced NSCLC (stage III-IV) patients with measurable baseline MTV, TLG, and cfDNA quantification. The best cut-offs for cfDNA levels, MTV, and TLG to predict progression-free survival and overall survival were determined using X-tile analysis. RESULTS: There were significant positive correlations between cfDNA and MTV (r = 0.488, p < 0.001) and between cfDNA and TLG (r = 0.554, p < 0.001). High-cfDNA levels and high-MTV/TLG negatively correlated with overall survival (OS) (all p < 0.001). Patients with high-MTV showed similar median OS irrespective of their cfDNA levels (low-cfDNA vs. high-cfDNA=9.2 vs 6.6 months; p > 0.05). However, patients with low-MTV and low-cfDNA levels showed longer OS than those with low-MTV and high-cfDNA levels (low-cfDNA vs. high-cfDNA=49.3 vs 11.5 months; p < 0.001). The patient group with low-TLG also showed similar trends. The cfDNA level was an independent prognostic factor for OS by Cox-proportional hazard analysis. CONCLUSION: Although the patients with high metabolic tumor burden had a poor prognosis, regardless of the biological behavior/aggressiveness of the tumor, patients with low metabolic tumor burden and high cfDNA levels showed a poor prognosis. Taken together, this study indicates a stronger prognostic value of baseline cfDNA levels in identifying patients with advanced NSCLC and personalizing their treatment strategies for better survival.

Regional glucose metabolism due to the presence of cerebral amyloidopathy in older adults with depression and mild cognitive impairment.

BACKGROUND: Depression is a risk factor for mild cognitive impairment (MCI) and for the conversion from MCI to Alzheimer's disease (AD). This study investigated regional cerebral glucose metabolism (rCMglc) in older adults with depression and MCI, either with or without amyloidopathy. METHODS: We recruited 31 older adults diagnosed with depression and MCI, and 21 older adults with normal cognition (NC). All participants completed demographic questionnaires and were examined with a standardized neuropsychological battery, F-18 fluorodeoxyglucose positron emission tomography (PET), and F-18 florbetaben PET. We classified subjects with depression and MCI into amyloid-ß-positive (CDAP; n = 16) and amyloid-ß-negative (CDAN; n = 15) groups. Pairwise rCMglc analyses were conducted between all three groups (CDAP vs. NC, CDAN vs. NC, and CDAP vs. CDAN). RESULTS: In comparison with the NC group, the CDAP group showed reduced rCMglc predominantly in temporoparietal regions, whereas the CDAN group showed lower rCMglc in regions of the frontal lobe, in addition to the temporoparietal regions. The CDAN group also showed lower rCMglc in right anterior cingulate and left inferior orbitofrontal regions, in a comparison between the CDAP and CDAN groups. LIMITATIONS: The generalizability of the findings is limited because this study has a relatively small number of participants. In addition, this study used cross-sectional design rather than longitudinal design. CONCLUSIONS: Our findings may provide a reference to assess the risk of future cognitive deterioration. Consequently, this study is expected to contribute to prevention and early identification of dementia associated with AD.