Search

Purposes: To explore the clinical feasibility and efficacy of a deep inspiration breath-hold (BH) PET/CT using [18F]AlF-NOTA-LM3 on upper abdominal lesions in patients with neuroendocrine tumors (NETs). Methods: Twenty-three patients underwent a free-breath (FB) whole-body PET/CT, including a 10 min/bed scan for the upper abdomen with a vital signal monitoring for respiratory gating (RG) followed by a 20-second BH PET/CT covering the same axial range. For the upper abdomen bed, the following PET series was reconstructed: a 2-min FB PET; RG PET (6 bins); a 20-second and 15-second BH PET (BH_15 and BH_20). Semi-quantitative analysis was performed to compare liver SUVmean, lesion SUVmax, MTV, its percentage difference and target-to-background ratio (TBR) between both BH PET and RG PET images. Subgroup analysis considered lesion location, MTV and SUVmax. A 5-point Likert scale was used to perform visual analysis and any missed or additional lesions were identified compared with RG PET. Results: Quantitative analysis on overall lesions (n = 78) revealed higher SUVmax and TBR, and smaller MTV for both BH PET compared to FB and RG PET, with lesion location-specific variations. Neither significant difference was observed in all metrics between RG and FB PET in larger lesions, nor in MTV in lower-uptake lesions. However, both BH PET significantly enhanced these measurements. In the visual analysis, both BH PET showed noninferior performance to RG PET, and were evaluated clinically acceptable. Additional and missed lesions were observed in FB and both BH PET compared with RG PET, but didn't alter the clinical management. The BH_15 PET showed comparable performance to BH_20 PET in any comparison. Conclusion: The BH PET/CT using [18F]AlF-NOTA-LM3 is effective in detecting upper abdominal lesions, offering more accurate quantitative measurements. Using a novel PET/CT scanner, a 15-second BH PET can provide comparable and superior performance to RG PET, indicating potential feasibility in clinical routines. [ABSTRACT FROM AUTHOR]

Purpose: Dynamic PET/CT scan of 68Ga-FAPI-04 in patients with suspected malignant hepatic lesions were retrospectively analyzed to find the optimal acquisition time with better lesion detection rate. Methods: Twenty-two patients with lesions confirmed by CT or MRI were performed with dynamic 68Ga-FAPI-04 PET/CT scan. Tracer uptake of lesions and normal organs at different time points were analyzed. Standardized uptake value (SUV) and tumor-to-background (TBR) were calculated based on the quantification of images. Results: SUV of normal organs decreased rapidly from 10 to 30 min and decreased gradually from 30 to 60 min. Besides, the uterus showed a particularly high uptake in all patients (12.62 ± 4.58 at 10 min p.i., 12.04 ± 3.99 at 30 min p.i., 10.92 ± 2.38 at 60 min p.i.). SUV of lesions decreased gradually, while TBR increased from 10- to 60-min post-injection. Visual analysis verified a comparable lesion detectability of 30 min and 60 min with images of 10 min showing a decreased lesion detection number. Conclusion: This study revealed that similar detection rates were achieved at both 30 and 60 min, suggesting a static scan at 30 min to be appropriate in the clinic. Besides, although with high lesion uptake, early 68Ga-FAPI-04 PET imaging at 10 min after tracer injection could cause missed lesion detection. [ABSTRACT FROM AUTHOR]

Introduction: The purpose of this study was to evaluate subjects with high-risk alcohol cardiotoxicity and patients with alcoholic cardiomyopathy (ACM) via dynamic 11C-Acetate positron emission tomography (PET) imaging as a myocardial oxidative metabolic probe. Methods and Results: We recruited 37 subjects with chronic alcohol consumption [18 with moderate consumption (MC), 19 with heavy consumption (HC)], 5 ACM patients, and 12 healthy controls to receive dynamic 11C-Acetate PET scans. PET imaging data were analyzed to calculate kinetic parameters (e.g., Kmono, K1 and k2) based on the mono-exponential and one-tissue compartmental models. Myocardial oxygen consumption (MVO2) and myocardial external efficiency (MEE) were then derived from these kinetic parameters. MVO2 was significantly lowered in the HC group and in ACM patients (0.121± 0.018 and 0.111 ± 0.017 mL·g−1·min−1, respectively) compared with those in healthy controls and MC subjects (0.144 ± 0.023 and 0.146 ± 0.027 mL·g−1·min−1, respectively; P <.01). MEE was significantly reduced in ACM patients (13.0% ± 4.3%) compared with those of healthy controls (22.4% ± 4.6%, P <.01), MC subjects (20.1% ± 4.5%, P <.05), and HC subjects (22.3% ± 4.5%, P <.001). Conclusion: Functional assessment via dynamic 11C-Acetate PET imaging may represent a clinically feasible probe for identifying cohorts with high-risk cardiotoxicity due to addictive alcohol consumption and ACM. [ABSTRACT FROM AUTHOR]

Background: Molecular imaging targeting angiogenesis can specifically monitor the early therapeutic effect of antiangiogenesis therapy. We explore the predictive values of an integrin αvβ3-targeted tracer, 99mTc-PEG4-E[PEG4-c(RGDfK)]2 (99mTc-3PRGD2), for monitoring the efficacy of Endostar antiangiogenic therapy and chemotherapy in animal models. Methods: The pancreatic cancer xenograft mice were randomly divided into four groups, with seven animals in each group and treated in different groups with 10 mg/kg/day of Endostar, 10 mg/kg/day of gemcitabine, 10 mg/kg/day of Endostar +10 mg/kg/day of gemcitabine at the same time, and the control group with 0.9% saline (0.1 ml/day). 99mTc-3PRGD2 scintigraphic imaging was carried out to monitor therapeutic effects. Microvessel density (MVD) was measured using immunohistochemical staining of the tumor tissues. The region of interest (ROI) of tumor (T) and contralateral corresponding site (NT) was delineated, and the ratio of radioactivity (T/NT) was calculated. Two-way repeated-measure analysis of variance (ANOVA) was used to assess differences between treatment groups. Results: Tumor growth was significantly lower in treatment groups than that in the control group (p < 0.05), and the differences were noted on day 28 posttreatment. The differences of 99mTc-3PRGD2 uptakes were observed between the control group and Endostar group (p = 0.033) and the combined treatment group (p < 0.01) on day 7 posttreatment and on day 14 posttreatment between the control group and gemcitabine group (p < 0.01). The accumulation of 99mTc-3PRGD2 was significantly correlated with MVD (r = 0.998, p = 0.002). Conclusion: With 99mTc-3PRGD2 scintigraphic imaging, the tumor response to antiangiogenic therapy, chemotherapy, and the combined treatment can be observed at an early stage of the treatments, much earlier than the tumor volume change. It provides new opportunities for developing individualized therapies and dose optimization. [ABSTRACT FROM AUTHOR]

Objective. Kinetic modeling of dynamic 11C-acetate PET imaging provides quantitative information for myocardium assessment. The quality and quantitation of PET images are known to be dependent on PET reconstruction methods. This study aims to investigate the impacts of reconstruction algorithms on the quantitative analysis of dynamic 11C-acetate cardiac PET imaging. Methods. Suspected alcoholic cardiomyopathy patients (N=24) underwent 11C-acetate dynamic PET imaging after low dose CT scan. PET images were reconstructed using four algorithms: filtered backprojection (FBP), ordered subsets expectation maximization (OSEM), OSEM with time-of-flight (TOF), and OSEM with both time-of-flight and point-spread-function (TPSF). Standardized uptake values (SUVs) at different time points were compared among images reconstructed using the four algorithms. Time-activity curves (TACs) in myocardium and blood pools of ventricles were generated from the dynamic image series. Kinetic parameters K1 and k2 were derived using a 1-tissue-compartment model for kinetic modeling of cardiac flow from 11C-acetate PET images. Results. Significant image quality improvement was found in the images reconstructed using iterative OSEM-type algorithms (OSME, TOF, and TPSF) compared with FBP. However, no statistical differences in SUVs were observed among the four reconstruction methods at the selected time points. Kinetic parameters K1 and k2 also exhibited no statistical difference among the four reconstruction algorithms in terms of mean value and standard deviation. However, for the correlation analysis, OSEM reconstruction presented relatively higher residual in correlation with FBP reconstruction compared with TOF and TPSF reconstruction, and TOF and TPSF reconstruction were highly correlated with each other. Conclusion. All the tested reconstruction algorithms performed similarly for quantitative analysis of 11C-acetate cardiac PET imaging. TOF and TPSF yielded highly consistent kinetic parameter results with superior image quality compared with FBP. OSEM was relatively less reliable. Both TOF and TPSF were recommended for cardiac 11C-acetate kinetic analysis. [ABSTRACT FROM AUTHOR]

Abstract: A 65-year-old woman was referred to our hospital because of a liver lesion revealed by ultrasound and CT in an outside institution. 18 F-FDG PET/CT images revealed an FDG-avid lesion in the left lateral lobe of the liver. Malignancy cannot be excluded. A subsequent resection was performed to remove the lesion. Postoperative pathology was hepatic cavernous hemangioma. This case suggests that PET/CT findings of FDG-avid hepatic cavernous hemangioma could mimic malignancy., Competing Interests: Conflicts of interest and sources of funding: The authors declare no conflict of interest. This work was supported by National High Level Hospital Clinical Research Funding (grant 2022-PUMCH-B-071)., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Increased expression of fibroblast-activating protein (FAP) in fibrous caps may contribute to progression of atherosclerotic plaques. Methods: Forty-one patients who underwent 68 Ga-conjugated quinoline-based FAP inhibitor ( 68 Ga-FAPI-04) PET/CT for noncardiovascular indications were retrospectively analyzed. Correlations were assessed between the uptake of 68 Ga-FAPI-04 in large arterial walls (SUV max and target-to-background ratio, TBR) and degree of calcification and cardiovascular risk factors. Results: Focal arterial uptake of 68 Ga-FAPI-04 or calcification was detected in 1,177 arterial segments in all 41 patients. TBR was negatively correlated with the degree of calcification (Hounsfield units) ( r = -0.27, P < 0.01). Mean TBR in higher-risk patients was greater than in lower-risk patients (2.2 ± 0.3 vs. 1.8 ± 0.3, P < 0.01). Immunohistochemical labeling of carotid plaques exhibited prominent FAP expression in a thin fibrous cap and moderate FAP expression in a thick cap. Conclusion: 68 Ga-FAPI-04 PET/CT might have potential for imaging fibroblastic activation in the arterial wall., (© 2022 by the Society of Nuclear Medicine and Molecular Imaging.)

Background: Molecular imaging targeting angiogenesis can specifically monitor the early therapeutic effect of antiangiogenesis therapy. We explore the predictive values of an integrin αvβ3-targeted tracer, 99m Tc-PEG 4 -E[PEG 4 -c(RGDfK)] 2 ( 99m Tc-3PRGD 2 ), for monitoring the efficacy of Endostar antiangiogenic therapy and chemotherapy in animal models., Methods: The pancreatic cancer xenograft mice were randomly divided into four groups, with seven animals in each group and treated in different groups with 10 mg/kg/day of Endostar, 10 mg/kg/day of gemcitabine, 10 mg/kg/day of Endostar +10 mg/kg/day of gemcitabine at the same time, and the control group with 0.9% saline (0.1 ml/day). 99m Tc-3PRGD 2 scintigraphic imaging was carried out to monitor therapeutic effects. Microvessel density (MVD) was measured using immunohistochemical staining of the tumor tissues. The region of interest (ROI) of tumor (T) and contralateral corresponding site (NT) was delineated, and the ratio of radioactivity (T/NT) was calculated. Two-way repeated-measure analysis of variance (ANOVA) was used to assess differences between treatment groups., Results: Tumor growth was significantly lower in treatment groups than that in the control group (p < 0.05), and the differences were noted on day 28 posttreatment. The differences of 99m Tc-3PRGD 2 uptakes were observed between the control group and Endostar group (p = 0.033) and the combined treatment group (p < 0.01) on day 7 posttreatment and on day 14 posttreatment between the control group and gemcitabine group (p < 0.01). The accumulation of 99m Tc-3PRGD 2 was significantly correlated with MVD (r = 0.998, p = 0.002)., Conclusion: With 99m Tc-3PRGD 2 scintigraphic imaging, the tumor response to antiangiogenic therapy, chemotherapy, and the combined treatment can be observed at an early stage of the treatments, much earlier than the tumor volume change. It provides new opportunities for developing individualized therapies and dose optimization., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Jin, Dong, Zheng, Shi, Liu, Huo, Wang and Li.)

Objective: Kinetic modeling of dynamic 11 C-acetate PET imaging provides quantitative information for myocardium assessment. The quality and quantitation of PET images are known to be dependent on PET reconstruction methods. This study aims to investigate the impacts of reconstruction algorithms on the quantitative analysis of dynamic 11 C-acetate cardiac PET imaging., Methods: Suspected alcoholic cardiomyopathy patients ( N = 24) underwent 11 C-acetate dynamic PET imaging after low dose CT scan. PET images were reconstructed using four algorithms: filtered backprojection (FBP), ordered subsets expectation maximization (OSEM), OSEM with time-of-flight (TOF), and OSEM with both time-of-flight and point-spread-function (TPSF). Standardized uptake values (SUVs) at different time points were compared among images reconstructed using the four algorithms. Time-activity curves (TACs) in myocardium and blood pools of ventricles were generated from the dynamic image series. Kinetic parameters K 1 and k 2 were derived using a 1-tissue-compartment model for kinetic modeling of cardiac flow from 11 C-acetate PET images., Results: Significant image quality improvement was found in the images reconstructed using iterative OSEM-type algorithms (OSME, TOF, and TPSF) compared with FBP. However, no statistical differences in SUVs were observed among the four reconstruction methods at the selected time points. Kinetic parameters K 1 and k 2 also exhibited no statistical difference among the four reconstruction algorithms in terms of mean value and standard deviation. However, for the correlation analysis, OSEM reconstruction presented relatively higher residual in correlation with FBP reconstruction compared with TOF and TPSF reconstruction, and TOF and TPSF reconstruction were highly correlated with each other., Conclusion: All the tested reconstruction algorithms performed similarly for quantitative analysis of 11 C-acetate cardiac PET imaging. TOF and TPSF yielded highly consistent kinetic parameter results with superior image quality compared with FBP. OSEM was relatively less reliable. Both TOF and TPSF were recommended for cardiac 11 C-acetate kinetic analysis.

Purpose To evaluate an integrin imaging approach based on single photon emission computed tomography (SPECT)/computed tomography (CT) by using technetium 99m ( 99m Tc)-dimeric cyclic arginine-glycine-aspartic acid (RGD) peptides with three polyethylene glycol spacers (3PRGD2) as the tracer to target the integrin α v β 3 expression in lung cancer and lymph node metastasis. Materials and Methods With ethics committee approval and written informed consent, 65 patients (41 male, 24 female; mean age, 60 years ± 11 [standard deviation]) with suspicious lung lesions were recruited with informed consent. The patients underwent both 99m Tc-3PRGD2 SPECT/CT and fluorine 18 ( 18 F) fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT within 1 week. Finally, 65 lung lesions in 53 patients were pathologically diagnosed as non-small cell lung cancer (NSCLC) and 14 lung lesions in 12 patients were benign. Per-region analysis of lymph nodes included 248 regions with metastasis and 56 negative regions. Twenty specimens from the removed lung lesions or lymph nodes were stained with integrin α v β 3 , CD34, and Ki-67 to correlate with the image findings. Receiver operating characteristic curve, z statistics, McNemar test, and χ 2 analysis were used to compare the diagnostic performance of the two imaging methods. Results 99m Tc-3PRGD2 SPECT/CT was found to be more specific than 18 F-FDG PET/CT in the per-region diagnosis of lymph node metastasis (specificity, 94.6% vs 75.0%; P = .008) when the sensitivity of the two methods was comparable (88.3% vs 90.7%; P = .557). There was no significant difference between the two methods in the per-lesion diagnosis of lung tumor (z = 0.82, P = .410). The accumulation level of 99m Tc-3PRGD2 was found in positive correlation with the integrin α v β 3 expression (r = 0.84, P = .001) and microvessel density (r = 0.63, P = .011) in the tumors. Conclusion 99m Tc-3PRGD2 SPECT/CT shows high specificity in the diagnosis of lymph node metastasis from NSCLC, which may benefit surgical decision making for the patients. © RSNA, 2016.

Cancer is becoming the largest threat to human health. Apart from classical anti-cancer therapies such as surgery, chemotherapies, and radiotherapy, many new therapies are being developed or translated into clinical use. These therapies include various neoadjuvant chemotherapies, minimally invasive treatments, and molecular-targeted therapies. However, none of these methods benefit all patients because treatment should be personalized according to the response of each patient. A futile therapy makes a patient miss the optimum time for treatment and increases the medical burden to the society. Thus, a great challenge is encountered in monitoring such therapies. Classical methods based on anatomical changes such as computed tomography (CT) and magnetic resonance imaging (MRI) have well-known limitations in early response evaluation. Positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) as tracer is a promising method especially when integrated with CT or MRI in one system. This article reviews the current status of monitoring anti-cancer therapies, including the evolution of evaluation criteria from the World Health Organization to the Response Evaluation Criteria in Solid Tumor and the PET Response Criteria in Solid Tumor. The advantages of 18F-FDG PET/CT for response evaluation are analyzed in various malignant tumors, and the pertinent weaknesses are discussed. Finally, several future directions in monitoring anti-cancer therapies are prospected.

Objective: The purpose of this article is to evaluate the feasibility of adenosine-stress dynamic myocardial perfusion imaging (MPI) with 128-MDCT dual-source CT for detecting myocardial ischemia in comparison with conventional catheter coronary angiography and nuclear MPI., Subjects and Methods: Thirty patients (21 men and nine women; mean [± SD] age, 59.2 ± 7.6 years) prospectively underwent a combined stress CT perfusion and CT angiography (CTA) examination. Complete time-attenuation curves of the myocardium were acquired with prospectively ECG-triggered axial images at two alternating positions. Myocardial blood flow (MBF) was quantified according to dynamic CT perfusion, and MBF values of normal and abnormal segments were compared. Findings on CT perfusion were compared with those for stress and rest SPECT. Perfusion defects according to CT were correlated to flow-obstructing stenosis detected on CTA and catheter coronary angiography., Results: On stress CT perfusion, 19 patients (63%) and 83 of 504 segments (16%) had perfusion abnormalities. There was a significant difference in MBF values between normal (142.9 ± 30.6 mL/100 mL/min) and hypoperfused (90.0 ± 22.8 mL/100 mL/min) segments (p < 0.001). With nuclear MPI results as a comparison, the sensitivity, specificity, positive predictive value, and negative predictive value of CT perfusion for identifying segments with perfusion defects were 0.85, 0.92, 0.55, and 0.98, respectively. On a per-vessel basis, sensitivity, specificity, positive predictive value, and negative predictive value for detecting flow-obstructing stenosis were, respectively, 1.00, 0.757, 0.541, and 1.00 for CT perfusion; 0.90, 0.514, 0.346, and 0.947 for CTA; and 0.90, 0.814, 0.581, and 0.966 for CT perfusion combined with CTA., Conclusion: Adenosine-stress CT perfusion detects myocardial perfusion defects in good correlation with nuclear MPI. CT perfusion combined with CTA improves the diagnostic accuracy for identifying flow-obstructing stenosis compared with CTA alone.