A machine learning-based PET/CT model for automatic diagnosis of early-stage lung cancer.

Objective: The aim of this study was to develop a machine learning-based automatic analysis method for the diagnosis of early-stage lung cancer based on positron emission tomography/computed tomography (PET/CT) data. Methods: A retrospective cohort study was conducted using PET/CT data from 187 cases of non-small cell lung cancer (NSCLC) and 190 benign pulmonary nodules. Twelve PET and CT features were used to train a diagnosis model. The performance of the machine learning-based PET/CT model was tested and validated in two separate cohorts comprising 462 and 229 cases, respectively. Results: The standardized uptake value (SUV) was identified as an important biochemical factor for the early stage of lung cancer in this model. The PET/CT diagnosis model had a sensitivity and area under the curve (AUC) of 86.5% and 0.89, respectively. The testing group comprising 462 cases showed a sensitivity and AUC of 85.7% and 0.87, respectively, while the validation group comprising 229 cases showed a sensitivity and AUC of 88.4% and 0.91, respectively. Additionally, the proposed model improved the clinical discrimination ability for solid pulmonary nodules (SPNs) in the early stage significantly. Conclusion: The feature data collected from PET/CT scans can be analyzed automatically using machine learning techniques. The results of this study demonstrated that the proposed model can significantly improve the accuracy and positive predictive value (PPV) of SPNs at the early stage. Furthermore, this algorithm can be optimized into a robotic and less biased PET/CT automatic diagnosis system.

Intravenous insulin preparation administration for myocardial viability 18F-FDG imaging has the potential to reduce radiation exposure dose.

OBJECTIVE: Fluorine-18-fluorodeoxyglucose (18F-FDG) injection activity is positively associated with radiation dose and positron emission tomography (PET) image count. Measurement error is greater with smaller counts; therefore, precise analysis is needed to avoid high doses of radiation exposure caused by high 18F-FDG injection. We aimed to identify and validate the optimal 18F-FDG injection activity and acquisition time for cardiac viability imaging with intravenous insulin preparation administration based on fixed 18F-FDG activity. MATERIALS AND METHODS: Cardiac PET images from 30 patients with coronary artery disease (CAD) were retrospectively reconstructed into different durations. An optimal product of the maximum standardized uptake value (SUV) of the myocardium, and segmental uptake (SU), and acquisition time (MSAT) was determined through a receiver operating characteristic curve. RESULTS: The optimal acquisition time (OAT) was equal to MSAT divided by mean SUV of the myocardium (MyoSUV) and was validated in another 26 patients with CAD. The optimal MSAT was 848.2s. In the validation group, the OAT was 129±76s (95% confidence interval, 99-160s), approximately one-third of the usual acquisition time. The MyoSUV and SU were equivalent between PET image duration of OAT and 600s (7.71±3.01 vs. 7.56±2.94; 67.1±15.4% vs. 67.7±15.6%). CONCLUSION: Intravenous insulin preparation administration has the potential to decrease the radiation exposure or acquisition time in cardiac viability 18F-FDG imaging to one-third, without losing the accurate measurement of MyoSUV or SU when reaching an OAT.

Elevated standardised uptake value of the free wall of the right ventricular myocardium is correlated with enlarged left ventricular end-diastolic volume among patients with heart failure with reduced ejection fraction: A retrospective study.

This study aimed to investigate the relationship between the standardised uptake value of the free wall of the right ventricular myocardium (SUVrv) and left ventricular end-diastolic volume (LVEDV) among patients with heart failure with reduced ejection fraction (HFrEF) with coronary artery disease (CAD). This retrospective study included 50 patients with CAD and HFrEF scheduled for cardiac viability imaging with electrocardiography-gated fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT). The maximal SUVrv was measured. The LVEDV and left ventricular ejection fraction (LVEF) were automatically measured using quantitative gated single-photon emission computed tomography. Plasma brain natriuretic peptide (BNP) levels were obtained from medical records.The LVEF (0.24±0.06) was markedly reduced while the LVEDV (201.5±59.9mL) and BNP level (1348.1±1382.9pg/mL) were remarkably elevated. The SUVrv was 3.7±1.7 and was similar between patients with and without diabetes. The SUVrv was significantly positively correlated with the LVEDV and BNP level (r=0.35, 0.45; P=0.01, ≤0.01, respectively) but was unrelated to the LVEF (r=0.11, P=0.44). Herein, SUVrv was elevated and significantly positively correlated with LVEDV and BNP levels among patients with CAD and HFrEF but was unrelated to LVEF and diabetic status.

18F-FDG PET/CT characteristics of solitary fibrous tumour of the pleura: single institution experience.

BACKGROUND: To date, published studies have shown that 18F-FDG PET/CT and CT have limited value in differentiating benign and malignant solitary fibrous tumours of the pleura (SFTP). This study aimed to determine whether the metabolic and morphological characteristics of 18F-FDG PET/CT can be a valuable addition to diagnostic tools for SFTPs. METHODS: From January 2016 to November 2021, we performed a retrospective review in 32 SFTPs patients who underwent 18F-FDG PET/CT scan. All the SFTP diagnoses were confirmed by surgical resection or biopsy samples. The metabolic parameters (including SUVmax, SUVmean, MTV, TLG, and SULmax) were obtained from 18F-FDG PET/CT images. RESULTS: Thirty-two patients with SFTP were consecutively identified. The malignant SFTPs have higher Ki-67 expression (P = 0.005). The study observed that tumour heterogeneity without contrast injection (P = 0.001) and intratumor blood vessels (P = 0.047) were morphological features associated with malignant SFTP. Malignant SFTP was more frequently observed with higher SUVmax values (P = 0.001), higher SUVmean values (P = 0.001), higher TLG values (P = 0.006), and higher SULmax values (P < 0.001). For predicting malignant SFTP, the AUC values of SUVmax, SUVmean, TLG, and SULmax obtained by the area under curve analysis were 0.970 (95% CI 0.907-1.000; P = 0.001), 0.874 (95% CI 0.675-1.000; P = 0.009), 0.807 (95% CI 0.654-0.961; P = 0.031), and 0.911 (95% CI 0.747-1.000; P = 0.004), respectively. CONCLUSION: The study showed that metabolic and morphological features were useful for distinguishing malignant from benign SFTPs.

Differential diagnostic value of 18F-FDG PET/CT in pulmonary carcinoids versus hamartomas.

RATIONALE AND OBJECTIVE: To assess the possibility of differentiating pulmonary carcinoids from hamartomas and typical from atypical carcinoids by means of 18F-FDG PET/CT. MATERIALS AND METHODS: We retrospectively reviewed 139 patients with pathologically proven pulmonary carcinoids and hamartomas who underwent 18F-FDG PET/CT before surgical resection. Receiver operating characteristics curves were calculated to determine the potential of SUVmax to discriminate between pulmonary carcinoids and hamartomas, typical and atypical carcinoids. The correlation between SUVmax and tumor size was analyzed by Spearman correlation analysis. RESULTS: SUVmax was significantly higher in pulmonary carcinoids than in hamartomas (p<0.001), and also higher in atypical carcinoids than in typical carcinoids (p = 0.034). With a SUVmax of 2.0 as a cutoff, the sensitivity, specificity, positive predictive value, and negative predictive value for 18F-FDG PET/CT to differentiate pulmonary carcinoids from hamartomas were 85.3%, 82.9%, 61.7%, and 94.6%, respectively. The cutoff value of SUVmax for differentiating atypical carcinoids from typical carcinoids was 4.1. The area under the receiver operating characteristics curve of SUVmax was 0.900 for carcinoids and hamartomas, and 0.722 for typical and atypical carcinoids. SUVmax was correlated with maximum tumor size in pulmonary carcinoids (r = 0.658, p <0.001) and in pulmonary hamartomas (r = 0.672, p <0.001). CONCLUSION: 18F-FDG PET/CT might be a useful tool in the differential diagnosis of carcinoids and hamartomas, and can also distinguish atypical from typical carcinoids. This may facilitate improved selection of patients for surgical resection and radiological follow-up.

Correlation between 18 F-FDG PET/CT semiquantitative parameters and Ki-67 expression in pulmonary mucosa-associated lymphoid tissue lymphoma.

INTRODUCTION: This study aims to investigate the correlation between 18 F-Fluoro-d-glucose positron emission tomography/computed tomography (18 F-FDG PET/CT) semiquantitative parameters and Ki-67 expression in pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma. METHODS: Twenty-eight patients with histologically confirmed pulmonary MALT lymphoma in 29 lesions who underwent 18 F-FDG PET/CT were retrospectively analysed. PET/CT images were analysed visually and semiquantitatively by measuring maximum standardized uptake value (SUVmax ), mean standardized uptake value (SUVmean ), metabolic tumour volume (MTV) and total lesion glycolysis (TLG). The correlation between morphological pattern, tumour size, Ki-67 expression and PET/CT semiquantitative parameters were also analysed. RESULTS: There were 16 male patients (57.1%) and 12 female patients (42.9%), and the mean age was 57.6 ± 9.7 years (range 43-73 years). Twenty-nine pulmonary lesions were identified in 28 patients: 12 (41.4%) presenting as consolidation, 9 (31.0%) as nodules, 5 (17.2%) as masses and 3 (10.3%) as ground glass opacities (GGOs). All of the 29 lesions were 18 F-FDG avid. SUVmax of the lesions was 4.4 ± 3.0 (range 1.1-15.3), SUVmean was 2.8 ± 1.9 (range 0.8-10.3), MTV was 15.9 ± 17.6 (range 0.9-82.1) and TLG was 48.7 ± 56.6 (range 0.9-205.6). The PET/CT semiquantitative parameters were not correlated with morphological pattern of pulmonary MALT lymphoma, which were correlated significantly with tumour size and Ki-67 expression. CONCLUSION: Pulmonary MALT lymphomas are 18 F-FDG avid, and 18 F-FDG PET/CT semiquantitative parameters (SUVmax , SUVmean , MTV and TLG) are significantly correlated with tumour size and Ki-67 expression. 18 F-FDG PET/CT plays a potential role in identifying lung MALT lymphomas with higher proliferation and more aggressive behaviour in clinical practice.

Association between 18F-FDG metabolic activity and programmed death ligand-1 (PD-L1) expression using 22C3 immunohistochemistry assays in non-small cell lung cancer (NSCLC) resection specimens.

OBJECTIVE: This study sought to investigate the association between 18F-fludeoxyglucose (18F-FDG) uptake in positron emission tomography/CT (PET/CT) scans and different programmed death ligand-1 (PD-L1) expression conditions in non-small cell lung cancer (NSCLC). METHODS: From October 2017 to December 2019, NSCLC was retrospectively identified in 419 consecutive patients who underwent 18F-FDG PET/CT scans and PD-L1 expression tests using the PD-L1 22C3 assay. The association between clinicopathological characteristics and PD-L1 expression was assessed. RESULTS: The frequency of PD-L1-positive tumours was 38.2% (160/419) in NSCLC. In NSCLC, the multivariate analysis showed a high maximum standardised uptake value (SUVmax) (p < 0.0001) and an EGFR wild type genotype (p = 0.027) was significantly associated with PD-L1-positivity. In adenocarcinoma (ADC), the multivariate analysis showed that a high SUVmax (p < 0.0001) was significantly associated with PD-L1-positivity. In NSCLC and ADC, a Mann-Whitney U test showed significant differences between groups with PD-L1 high expression and PD-L1 low expression levels in terms of SUVmax (p = 0.011 and p = 0.013, respectively). The results of the receiver operating characteristic curve analysis showed that the area under the curve of the SUVmax was 0.767 (95% CI, 0.720-0.814; p < 0.0001) and 0.712 (95% CI, 0.651-0.774; p < 0.0001) in NSCLC and ADC, respectively. CONCLUSION: The study demonstrates that the SUVmax was significantly associated with PD-L1 expression in NSCLC and ADC. The SUVmax was significantly different between the PD-L1 high and low expression conditions, as quantified using a PD-L1 22C3 assay. ADVANCES IN KNOWLEDGE: This study provides direct evidence that SUVmax as a metabolic biomarker may help select patients with NSCLC likely to benefit from pembrolizumab.

Relationship between SP142 PD-L1 Expression and 18F-FDG Uptake in Non-Small-Cell Lung Cancer.

Objectives: Immune checkpoint blockers constitute the first-line treatment for advanced non-small-cell lung cancer (NSCLC) with ≥50% PD-L1 expression. In NSCLC, PD-L1 positivity is correlated with high 18F-fluorodeoxyglucose (18F-FDG) uptake. However, these studies only included patients undergoing surgical resection, almost all in their early stages. Moreover, differences in 18F-FDG uptake between NSCLC with high (≥50%) and low (49%) PD-L1 expression remain unknown. We aimed to investigate the association between metabolic parameter 18F-FDG uptake and PD-L1 expression status in NSCLC patients. Methods: From February 2017 to June 2018, 428 consecutive NSCLC patients who underwent 18F-FDG positron emission tomography/computed tomography (PET/CT) and SP142 PD-L1 expression analysis were retrospectively assessed. The association between clinicopathological characteristics and PD-L1 expression was examined. Results: The frequency of PD-L1-positive tumors was 38.1% (163/428), 28.5% (91/319), and 64.2% (61/95) for NSCLC, adenocarcinoma (ADC), and squamous cell carcinoma (SCC), respectively. Maximal standard uptake (SUVmax) was significantly higher in PD-L1-positive than in PD-L1-negative NSCLC (p < 0.0001), ADC (p < 0.0001), and SCC (p=0.006). SUVmax was significantly higher in NSCLC (p=0.001) and ADC (p=0.003) with high rather than low PD-L1 expression. The receiver operating characteristic curve yielded area under the curve values of 0.726 (95% CI, 0.679-0.774, p < 0.0001), 0.694 (95% CI, 0.634-0.755, p < 0.0001), and 0.625 (95% CI, 0.513-0.738, p=0.044) for NSCLC, ADC, and SCC, respectively. Conclusion: 18F-FDG tumor uptake is strongly, positively correlated with PD-L1 expression in NSCLC and significantly differs between high and low PD-L1-expressing individuals.

Value of 18F-FDG PET/computed tomography in predicting the simplified WHO grade of malignancy in thymic epithelial tumors.

OBJECTIVE: To investigate the value of 18F-fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) in predicting the simplified WHO grade of malignancy in thymic epithelial tumors. MATERIALS AND METHODS: We retrospectively reviewed 81 patients with pathologically proven thymic epithelial tumors who underwent F-FDG PET/CT before surgical resection. Maximum standardized uptake value (SUVmax) and SUVmax/tumor size were measured on the primary lesion. A receiver operating characteristics (ROC) curve were performed for assessing the ability of F-FDG PET/CT as a predictor of the simplified WHO classification. RESULTS: There were 43 male patients (53.1%) and 38 female patients (46.9%), and the mean age was 55.6 ± 11.9 years. The mean tumor size was 53.2 ± 21.4 mm. There were 24 low-risk thymomas (29.6%) (A, AB, and B1), 29 high-risk thymomas (35.8%) (B2 and B3), and 28 thymic carcinomas (34.6%). The SUVmax and SUVmax/tumor size were found to be predictive factors that were useful to distinguish thymomas and thymic carcinomas, and area under the ROC curve were 0.820 and 0.691, respectively (P < 0.05), and the cutoff value for discriminating thymomas and thymic carcinomas was 5.34. CONCLUSION: In conclusion, a significant relationship was observed between SUVmax, SUVmax/tumor size and histological WHO classification of thymic epithelial tumors. F-FDG PET/CT may be useful for predicting the grade of malignancy in thymic epithelial.

Research on the method of controlling the 99mTc-Technegas inhaled during 1-day pulmonary ventilation/perfusion imaging.

OBJECTIVE: Our purpose was to establish a simple and feasible method for monitoring and controlling the Tc-Technegas inhaled to improve the success ratio of imaging and ensure the imaging quality. MATERIALS AND METHODS: The relationship between the success ratio and the pulmonary ventilation counting rate (VCR) of 113 cases, the activity of perfusion imaging agents injected and the pulmonary perfusion counting rate (PCR) of another 114 cases were analysed retrospectively. And combined with the relationship between the surface radioactivity monitoring value and the SPECT probe counting rate of a pulmonary model, the effective range of the VCR and the surface radioactivity monitoring value were determined. Two hundred fifty cases with Tc-Technegas inhaled monitored and controlled were used to verify the reliability and practicability of this method. RESULTS: The VCR of the ventilation/perfusion imaging with deep venous thrombosis imaging and the ventilation/perfusion imaging without deep venous thrombosis imaging was in 1.0-3.0 kct/s and 1.0-2.0 kct/s when the monitoring values of handheld radiation monitor was within the range of 60-170 µSv/h and 60-110 µSv/h, respectively. The success ratio of the V/Q-Only increased from 48.9% (43/88) of the control group to 80.8% (122/151) of the experimental group. The VCR in the two groups was examined by the non-parametric Mann-Whitney U test (P < 0.001), which indicated that there was a significant difference between the experimental group and the control group. CONCLUSION: The external monitoring method established in this study was of great significance in improving the success ratio of 1-day pulmonary ventilation/perfusion imaging and ensuring the image quality.

Dual-modality imaging of atherosclerotic plaques using ultrasmall superparamagnetic iron oxide labeled with rhodamine.

Aim: The diagnosis of vulnerable atherosclerotic plaques remains challenging. This study labeled ultrasmall superparamagnetic iron oxide with rhodamine (USPIO-R) and evaluated USPIO-R for imaging atherosclerotic plaques. Methods: Apolipoprotein E-deficient mice were fed a high-fat diet and underwent MRI before and after an intravenous injection of USPIO-R. Subsequently, an aortic specimen from the mice was removed and sliced for fluorescence imaging and Prussian blue and immunofluorescent staining. Results: T2 signal loss appeared and persisted in the aortic plaque postinjection, and spontaneous fluorescence from the plaque was observed. The accumulated mechanism of USPIO-R by plaque was the macrophage internalization by Prussian blue and immunofluorescence. Conclusion: USPIO-R is a promising dual-modality probe for diagnosing and monitoring vulnerable atherosclerotic plaques.

18F-FDG PET/CT imaging in pulmonary sarcomatoid carcinoma and correlation with clinical and genetic findings.

OBJECTIVE: Pulmonary sarcomatoid carcinoma (PSC) is a rare subtype of non-small-cell lung cancer with poor prognosis. This study analyzed 18F-FDG PET/CT in PSC and possible correlations with the clinical and genetic findings. METHODS: Pre-operative 18F-FDG PET/CT findings and parameters of maximum standard uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of primary lesion (MTV-P, TLG-P), and combination of primary lesion and metastases (MTV-C, TLG-C) were retrospectively analyzed in 24 patients with PSC confirmed by post-operative pathology. Tumor location, size, TNM stage, serum tumor markers, histopathological features, and mutations were also reviewed. Furthermore, progression-free survival (PFS) of 24 patients was analyzed. RESULTS: All 24 enrolled patients (20 men; 4 women; age: 62 ± 9 years) had single PSC, including 8 spindle cell carcinomas and 16 pleomorphic carcinomas. Serum levels of tumor markers were found to be abnormally increased sporadically. Six patients had central PSC, and 18 had peripheral PSC (diameter: 41 ± 16 mm). Eighteen lesions were located in the upper lobes of bilateral lungs, and 22 showed necrosis. Five cases were at TNM stage I, 12 at stage II, and 7 at stage III. The primary tumors were FDG avid in the 24 cases, with SUVmax of 17.2 ± 10.6. There were no correlations of SUVmax with tumor location, size, TNM stage, or histopathological subtypes. Programmed cell death ligand 1 (PD-L1) expression was detected in 21 cases (positivity rate: 87.5%). SUVmax of 17 lesions with PD-L1 expression degree ≥ 50% was obviously higher than that < 50% (P < 0.05). Kirsten rat sarcoma viral oncogene homolog (KRAS) gene mutation was found in six cases, and their SUVmax was significantly higher than that without KRAS mutation (P < 0.05). Furthermore, the median PFS of the 24 patients was 14 months, and 12-month and 24-month PFS rates were 55.9% and 27.8%, respectively. Only TLG-P and KRAS mutations of primary lesions were significantly associated with PFS. CONCLUSIONS: PSC tended to present with intense 18F-FDG accumulation on PET/CT, and SUVmax was useful for assessing PD-L1 and KRAS expression of PSC. TLG-P and KRAS mutation were independent prognostic factors of PSC.

Malignant Perivascular Epithelioid Cell Tumor of Lung on FDG PET/CT.

Chest CT images were acquired in a 67-year-old man to evaluate a left lung mass revealed by chest radiography. The image findings suggested possible pulmonary malignancy. FDG PET/CT was performed for staging, which showed the abnormally increased activity in the lung mass with hypermetabolic lymph node. Pathology from the biopsy confirmed malignant perivascular epithelioid cell tumor.

Detecting Vulnerable Atherosclerotic Plaques by 68Ga-Labeled Divalent Cystine Knot Peptide.

Integrin αvß3 has been considered as a promising biomarker for vulnerable atherosclerotic plaques, and it is highly expressed by those instability-associated factors, such as macrophages, vessel endothelial cells, and smooth muscle cells. Our previous study successfully showed that the 64Cu-labeled divalent (containing two RGD motifs) cystine knot peptide, 64Cu-NOTA-3-4A, had high binding affinity and specificity in targeting vulnerable carotid atherosclerotic plaques with increased αvß3 levels. Therefore, considering that 68Ga has excellent nuclear physical properties for positron emission tomography (PET), this study aimed to investigate the feasibility of using 68Ga-NOTA-3-4A for PET study of vulnerable atherosclerotic plaques. The vulnerable carotid atherosclerotic plaques were induced and maintained in ApoE-/- mice through carotid artery ligation and a high-fat diet. Divalent knottin peptide 3-4A was synthesized through solid-phase peptide synthesis chemistry and radiolabeled with 68Ga after being conjugated with 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA). The probe stability was analyzed in phosphate buffered saline (PBS) buffer and mouse serum. ApoE-/- mice with atherosclerotic plaques ( n = 4) were imaged by PET/CT at 1 and 2 h after the tail vein injection of 68Ga-NOTA-3-4A. The targeting specificity was determined by coinjection of 68Ga-NOTA-3-4A and nonradioactive c(RGDyK) peptide. The carotid artery tissues were removed, and immunofluorescent staining was performed to evaluate αvß3 integrin expression. It was found that 68Ga-NOTA-3-4A displayed high stability in both PBS buffer and mouse serum. Small animal PET/CT images and quantification analysis indicated the quick and high plaque uptake of 68Ga-NOTA-3-4A (6.67 ± 1.44 and 2.97 ± 0.46%ID/g at 1 and 2 h, respectively). The plaque-to-normal artery ratio was 15.88 and 9.90 at 1 and 2 h, respectively. Furthermore, the plaque accumulation of 68Ga-NOTA-3-4A was significantly inhibited via coinjection of c(RGDyK). Finally, immunostaining identified integrin αvß3 expressed by macrophages, vessel endothelial cells, and smooth muscle cells. In summary, 68Ga-NOTA-3-4A has high potential to be a promising PET tracer for imaging vulnerable atherosclerotic plaques.

A Case of Mediastinal Leiomyosarcoma Demonstrated on FDG PET/CT Imaging.

A 56-year-old man presented with persisting chest tightness over 1 month. A mediastinal mass was found by chest radiography. To further evaluate the mass, chest CT was performed and the malignancy was suspected. Staging FDG PET/CT demonstrated a hypermetabolic lesion located in the left middle mediastinum without extra-lesion involvement. The lesion pathologically confirmed mediastinal leiomyosarcoma after surgical resection.

Maxillofacial Spindle Cell Sarcoma With Lung Metastases on FDG PET/CT Imaging.

A 45-year-old man presented with episodes of cough and chest discomfort. CT examination showed multiple nodules of bilateral lungs. The pathology of CT-guided biopsy was consistent with spindle cell sarcoma. FDG PET/CT scan was performed to detect the primary lesion, which showed that in addition to multiple hypermetabolic pulmonary nodules, a mass in the right maxillofacial region with high FDG uptake was also found. A biopsy confirmed spindle cell sarcoma.

18F-FDG PET/CT characteristics of pulmonary sclerosing hemangioma vs. pulmonary hamartoma.

The radiological features of pulmonary sclerosing hemangioma (PSH) and pulmonary hamartoma are poorly specified. Thus, the present study aimed to compare and analyze the characteristics of fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in PSH versus pulmonary hamartoma. 18F-FDG PET/CT characteristic findings of 12 patients with PSH and 14 patients with pulmonary hamartoma were retrospectively reviewed. A total of 12 lesions were detected from the 12 patients with PSH, of which 3 masses exhibited calcification. The mean diameter and standardized maximum uptake value (SUVmax) were 1.9±0.7 cm and 2.6±1.0, respectively, and there was no significant correlation between the lesion size and SUVmax (P>0.05). For the 14 patients with pulmonary hamartoma, 14 lesions were found, of which 4 exhibited calcification. The mean diameter and SUVmax were 1.7±0.8 cm and 1.5±0.6, respectively, and there was a significant correlation between the size and SUVmax (r=0.625, r2=0.391, P<0.05). Although there was no significant difference between the size of PSH and pulmonary hamartoma (P>0.05), the SUVmax of PSH was significantly higher than that of pulmonary hamartoma (P<0.05). Moreover, the SUVmax of 1.95 was applied as a cutoff for the diagnosis of PSH, and the resulting sensitivity and specificity for PET/CT to differentiate PSH from pulmonary hamartoma were 83.3 and 78.6%, respectively. Although the morphological features were not specific, PSH showed significantly higher FDG accumulation than pulmonary hamartoma on PET/CT imaging, which may aid the differential diagnosis. Further studies with larger populations are warranted to confirm these study results.

Pilot Study of 64CuCl2 for PET Imaging of Inflammation.

Copper(II) ion (Cu2+) is the essential element for numerous pathophysiological processes in vivo. Copper transporter 1 (CTR1) is mainly responsible for maintaining Cu2+ accumulation in cells, which has been found to be over-expressed in inflammatory tissues. Therefore, we explored the potential application of 64CuCl2 for PET imaging of inflammation through targeting CTR1. The animal models of H2O2 induced muscle inflammation and lipopolysaccaharide induced lung inflammation were successfully established, then imaged by small animal PET (PET/CT) post-injection of 64CuCl2, and PET images were quantitatively analyzed. H&E and immunohistochemical (IHC) staining and western blot experiments were performed for evaluating CTR1 levels in the inflammatory and control tissues. Both inflammatory muscle and lungs can be clearly imaged by PET. PET image quantitative analysis revealed that the inflammatory muscle and lungs showed significantly higher 64Cu accumulation than the controls, respectively (p < 0.05). Furthermore, IHC staining and western blot analysis demonstrated that compared with the controls, CTR1 expression was increased in both the inflammatory muscle and lungs, which was consistent with the levels of 64Cu2+ accumulation in these tissues. 64CuCl2 can be used as a novel, simple, and highly promising PET tracer for CTR1 targeted imaging of inflammation.

18F-FDG PET/CT Imaging of Tracheal Mucoepidermoid Carcinoma.

A 54-year-old woman presented with dry cough for 3 months. An FDG PET/CT was performed to evaluate a tracheal nodule, which was revealed by chest CT. The PET/CT images showed increased FDG uptake with SUVmax of 3.3 in the known tracheal lesion. The results of pathological examination from the specimen of bronchoscopy were consistent with tracheal mucoepidermoid carcinoma.