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OBJECTIVES: There has been developed a clinical dynamic total-body 68Ga-DOTATATE PET/CT imaging protocol that allows quantitative imaging of net influx rate (Ki). Using qualitative and quantitative analyses of clinical studies, this retrospective study aims to assess whether parametric Ki images improve lesion detectability. METHODS: Using a 194-cm axial field-of-view PET/CT scanner, 52 patients with neuroendocrine tumors underwent a 60-min dynamic total-body 68Ga-DOTATATE scan. Parametric Ki images and static standardized uptake value (SUV) images were generated. In addition to visual inspection of both sets of images, a quantitative analysis of 249 individual lesions was conducted using the target-to-background (TBR) metric. RESULTS: There were 52 patients who underwent dynamic total-body 68Ga-DOTATATE PET/CT scans. A total of 249 lesions were evaluated, of which 66 lesions were biopsy-proven and 183 lesions were unproven. Ki images produced two fewer false positives than the SUV images. Overall, our results from 66 proven NET lesions suggested similar sensitivity (98.5%) but improved accuracy (from 95.6 to 97.1%) and potentially enhanced specificity with Ki over SUV imaging. Besides, there was no difference in the number of pathological lesions identified visually in both images. However, Ki TBR was significantly higher than SUV TBR quantitatively (P < 0.001). CONCLUSIONS: Patlak Ki imaging provides nuclear physicians with a PET image with higher tumor contrast which may enhance confidence in diagnosis with possibly reduced false positive results, albeit an equivalent detectability, compared to static SUV image.
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Tumores Neuroendócrinos , Compostos Organometálicos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Humanos , Tumores Neuroendócrinos/diagnóstico por imagem , Tumores Neuroendócrinos/patologia , Tumores Neuroendócrinos/metabolismo , Masculino , Feminino , Pessoa de Meia-Idade , Estudos Retrospectivos , Idoso , Adulto , Transporte Biológico , Idoso de 80 Anos ou mais , Processamento de Imagem Assistida por Computador/métodosRESUMO
ABSTRACT: This study aimed to evaluate the clinical value of automated breast volume scanner (ABVS) compared with hand-held ultrasound (HHUS). From January 2015 to May 2019, a total of 912 breast lesions in 725 consecutive patients were included in this study. κ statistics were calculated to identify interobserver agreement of ABVS and HHUS. The diagnostic performance for ABVS and HHUS was expressed as the area under the receiver operating characteristic curve, as well as the corresponding 95% confidence interval, sensitivity, and specificity. The sensitivities of ABVS and HHUS were 95.95% and 93.69%, and the specificities were 85.47% and 81.20%, respectively. A difference that nearly reached statistical significance was observed in sensitivities between ABVS and HHUS (P = 0.0525). The specificity of ABVS was significantly higher than that of HHUS (P = 0.006). When lesions were classified according to their maximum diameter, the sensitivity and specificity of ABVS were significantly higher than HHUS for lesions ≤20 mm, while they made no statistical significance between ABVS and HHUS for lesions >20 mm. The interobserver agreement for ABVS was better than that of HHUS. Automated breast volume scanner was more valuable than HHUS in diagnosing breast cancer, especially for lesions ≤20 mm, and it could be a valuable diagnostic tool for breast cancer.
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Neoplasias da Mama , Humanos , Feminino , Neoplasias da Mama/diagnóstico por imagem , Mama/diagnóstico por imagem , Ultrassonografia , Curva ROCRESUMO
OBJECTIVES: To investigate the earliest optimal timing for positron emission tomography (PET) scans after 68Ga-fibroblast activation protein inhibitor-04 ([68Ga]Ga-FAPI-04) injection. METHODS: This prospective study enrolled patients who underwent 60-min dynamic 68Ga-FAPI-04 total-body PET/CT scans; the images were reconstructed at 10-min intervals (G0-10, G10-20, G20-30, G30-40, G40-50, and G50-60), and the [68Ga]Ga-FAPI-04 uptake patterns were evaluated. The standardised uptake value (SUV), liver signal-to-noise ratio (SNR), and lesion-to-background ratios (LBRs) for different time windows were calculated to evaluate image quality and lesion detectability. The period from 30 to 40 min was then split into overlapping 5-min intervals starting 1 min apart for further evaluation. G50-60 was considered the reference. RESULTS: A total of 30 patients with suspected malignant tumours were analysed. In the images reconstructed over 10-min intervals, longer acquisition times were associated with lower background uptake and better image quality. Some lesions could not be detected until G30-40. The lesion detection rate, uptake, and LBRs did not differ significantly among G30-40, G40-50, and G50-60 (all p > 0.05). The SUVmean and LBRs of primary tumours in the reconstructed images did not differ significantly among the 5-min intervals between 30 and 40 min; for metastatic and benign lesions, G34-39 and G35-40 showed significantly better SUVmean and LBR values than the other images. The G34-39 and G50-60 scans showed no significant differences in uptake, LBRs, or detection rates (all p > 0.05). CONCLUSION: The earliest optimal time to start acquisition was 34 min after injection of half-dose [68Ga]Ga-FAPI-04. CLINICAL RELEVANCE STATEMENT: This study evaluated 68Ga-fibroblast activation protein inhibitor-04 ([68Ga]Ga-FAPI-04) uptake patterns by comparing the image quality and lesion detection rate with 60-min dynamic [68Ga]Ga-FAPI-04 total-body PET/CT scans and identified the earliest optimal scan time after [68Ga]Ga-FAPI-04 injection. KEY POINTS: ⢠A prospective single-centre study showed that the earliest optimal time point to start acquisition was 34 min after injection of half-dose [68Ga-fibroblast activation protein inhibitor-04 (68Ga]Ga-FAPI-04). ⢠There were statistically significant differences in standardised uptake value, lesion-to-background ratios, and lesion detectability between scans before and after 34 min from the injection of [68Ga]Ga-FAPI-04, but these values did not change further from 34 to 60 min after injection. ⢠With a reasonable acquisition time, the image quality could still meet diagnostic requirements.
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Radioisótopos de Gálio , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Compostos Radiofarmacêuticos , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Estudos Prospectivos , Idoso , Compostos Radiofarmacêuticos/farmacocinética , Compostos Radiofarmacêuticos/farmacologia , Imagem Corporal Total/métodos , Fatores de Tempo , Adulto , Neoplasias/diagnóstico por imagem , Idoso de 80 Anos ou mais , Razão Sinal-Ruído , QuinolinasRESUMO
Background: Accurate tumour response prediction to targeted therapy allows for personalised conversion therapy for patients with unresectable colorectal cancer liver metastases (CRLM). In this study, we aimed to develop and validate a multi-modal deep learning model to predict the efficacy of bevacizumab in patients with initially unresectable CRLM using baseline PET/CT, clinical data, and colonoscopy biopsy specimens. Methods: In this multicentre cohort study, we retrospectively collected data of 307 patients with CRLM from the BECOME study (NCT01972490) (Zhongshan Hospital of Fudan University, Shanghai) and two independent Chinese cohorts (internal validation cohort from January 1, 2018 to December 31, 2018 at Zhongshan Hospital of Fudan University; external validation cohort from January 1, 2020 to December 31, 2020 at Zhongshan Hospital-Xiamen, Shanghai, and the First Hospital of Wenzhou Medical University, Wenzhou). The main inclusion criteria were that patients with CRLM had pre-treatment PET/CT images as well as colonoscopy specimens. After extracting PET/CT features with deep neural networks (DNN) and selecting related clinical factors using LASSO analysis, a random forest classifier was built as the Deep Radiomics Bevacizumab efficacy predicting model (DERBY). Furthermore, by combining histopathological biomarkers into DERBY, we established DERBY+. The performance of model was evaluated using area under the curve (AUC), sensitivity, specificity, positive predictive value, and negative predictive value. Findings: DERBY achieved promising performance in predicting bevacizumab sensitivity with an AUC of 0.77 and 95% confidence interval (CI) [0.67-0.87]. After combining histopathological features, we developed DERBY+, which had more robust accuracy for predicting tumour response in external validation cohort (AUC 0.83 and 95% CI [0.75-0.92], sensitivity 80.4%, specificity 76.8%). DERBY+ also had prognostic value: the responders had longer progression-free survival (median progression-free survival: 9.6 vs 6.3 months, p = 0.002) and overall survival (median overall survival: 27.6 vs 18.5 months, p = 0.010) than non-responders. Interpretation: This multi-modal deep radiomics model, using PET/CT, clinical data and histopathological data, was able to identify patients with bevacizumab-sensitive CRLM, providing a favourable approach for precise patient treatment. To further validate and explore the clinical impact of this work, future prospective studies with larger patient cohorts are warranted. Funding: The National Natural Science Foundation of China; Fujian Provincial Health Commission Project; Xiamen Science and Technology Agency Program; Clinical Research Plan of SHDC; Shanghai Science and Technology Committee Project; Clinical Research Plan of SHDC; Zhejiang Provincial Natural Science Foundation of China; and National Science Foundation of Xiamen.
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PURPOSE: 18F-FDG PET/MR has been applied to the diagnosis and preoperative staging in various tumor types; however, reports using PET/MR in hilar cholangiocarcinoma (HCCA) are rare. We investigated the value of PET/MR for preoperative staging and compared it with PET/CT in HCCA. METHODS: Fifty-eight patients with HCCA confirmed by pathology were retrospectively analyzed. 18F-FDG PET/CT imaging was performed first, followed with whole-body PET/MR imaging. SUVmax of tumor and normal liver tissue were measured. Paired T test was used to compare SUVmax of tumor and normal liver tissue of PET/CT and PET/MR. In addition, McNemar test was used to compare the accuracy of TNM staging and Bismuth-Corlette typing between PET/CT and PET/MR. RESULTS: There was no significant difference in SUVmax between PET/CT and PET/MR in primary tumor lesions (6.6 ± 5.5 vs. 6.8 ± 6.2, P = 0.439). SUVmax of PET/CT and PET/MR in normal liver parenchyma was significantly different (3.0 ± 0.5 vs. 2.1 ± 0.5, P < 0.001). The accuracy of PET/MR in diagnosing T staging and N staging was significantly higher than those of PET/CT (72.4% vs. 58.6%, P = 0.022 and 84.5% vs. 67.2%, P = 0.002). There was no significant difference between PET/CT and PET/MR in M staging (94.8% vs. 98.3%, P = 0.5). The classification accuracy of PET/MR in Bismuth-Corlette was significantly higher than that of PET/CT (89.7% vs. 79.3%), P = 0.031. CONCLUSIONS: The diagnostic accuracy of 18F-FDG PET/MR was superior to that of PET/CT in preoperative T staging, N staging, and Bismuth-Corlette classification of HCCA. In M staging, the diagnostic accuracy of PET/MR was similar to that of PET/CT.
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Neoplasias dos Ductos Biliares , Tumor de Klatskin , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Fluordesoxiglucose F18 , Tumor de Klatskin/patologia , Tumor de Klatskin/cirurgia , Estadiamento de Neoplasias , Estudos Retrospectivos , Bismuto , Neoplasias dos Ductos Biliares/patologiaRESUMO
PURPOSE: Positron emission tomography/computed tomography (PET/CT) based on fibroblast activation protein inhibitors (FAPI) has shown complementary values to 2-[18F]-fluoro-2-deoxy-D-glucose ([18F]FDG) in cancer imaging. This study aimed to investigate the feasibility of a one-stop FDG-FAPI dual-tracer imaging protocol with dual-low activity for oncological imaging. METHODS: Nineteen patients with malignancies underwent one-stop [18F]FDG (0.37 MBq/kg) PET (PETFDG) and dual-tracer PET 30-40 and 50-60 min (hereafter, PETD30-40 and PETD50-60, respectively) after additional injection of [68Ga]Ga-DOTA-FAPI-04 (0.925 MBq/kg), with a single diagnostic CT to generate the PET/CT. The lesion detection rate and tumor-to-normal ratios (TNRs) of tracer uptake were compared between PETFDG/CT and PETD50-60/CT and between PETD50-60/CT and PETD30-40/CT. In addition, a visual scoring system was established to compare the lesion detectability. RESULTS: The dual-tracer PETD50-60 and PETD30-40/CT showed similar performance in detecting primary tumors but presented significantly higher lesion TNRs than PETFDG. Significantly, more metastases with higher TNRs were identified on PETD50-60 than PETFDG (491 vs. 261, P < 0.001). The dual-tracer PETD50-60 received significantly higher visual scores than single PETFDG (111 vs. 10) in demonstrating both primary tumors (12 vs. 2) and metastases (99 vs. 8). However, these differences were not significant between PETD50-60 and PETD30-40. These resulted in tumor upstaging in 44.4% patients taking PET/CT for initial assessment, and more recurrences (68 vs. 7) were identified in patients taking PET/CT for restaging, both on PETD50-60 and PETD30-40, compared to PETFDG. The reduced effective dosimetry per patient (26.2 ± 2.57 mSv) was equal to that of a single standard whole-body PET/CT. CONCLUSION: The one-stop dual-tracer dual-low-activity PET imaging protocol combines the strengths of [18F]FDG and [68Ga]Ga-DOTA-FAPI-04 with shorter duration and lesser radiation and is thus clinically applicable.
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Fluordesoxiglucose F18 , Quinolinas , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Estudos de Viabilidade , Radioisótopos de Gálio , Tomografia por Emissão de PósitronsRESUMO
OBJECTIVES: Validation of [18F]FDG PET/CT at ultralow-dose (0.37 MBq/kg) and compared to imaging at half-dose (1.85 MBq/kg). METHODS: This prospective head-to-head intraindividual study compared dynamic and static parameters of ultralow-dose with half-dose [18F]FDG total-body PET/CT. In static imaging, the ultralow-dose groups of PET images were denoted ULD5, 60-65 min; ULD8, 60-68 min; ULD10, 60-70 min; and ULD15, 60-75 min. The half-dose group images were reconstructed to 60-61, 60-62, 60-63, and 60-75 min, defined as LD1, LD2, LD3, and LD15, respectively. A 5-point Likert scale was used to subjectively evaluate the quality of static PET images, with a score greater than 3 considered to meet the requirements for clinical diagnosis. RESULTS: Thirty participants were included in this study, and in terms of kinetic indicators, no special differences were found between the two groups of normal organs and lesions. In static images, those in groups ULD8 and LD2 achieved scores of [Formula: see text] 3.0, meeting the requirements for clinical diagnosis. In static imaging, four lesions were missed in the LD1 group with a lesion detectability of 89.7% (35/39). In the meantime, lesions were not missed in the whole ultra-low dose group (ULD5, ULD8, ULD10, and ULD15) and half-dose groups (LD2 and LD3). CONCLUSIONS: Compared with half-dose imaging, ultralow-dose [18F]FDG total-body PET/CT imaging is clinically feasible, and there was no meaningful difference between the two groups of quantitative and qualitative analysis either dynamic or static images. Total-body PET/CT with ultralow-dose activity, the corresponding acquisition time of 8 min provides acceptable image quality and lesion detection. TRIAL REGISTRATION: ClinicalTrials.gov identifier: ChiCTR2000036487 KEY POINTS: ⢠A prospective single-center study showed that the total-body PET scanner allows ultralow-dose [18F]FDG imaging with acceptable image quality and lesion detectability. ⢠For the participant, radiation exposure can be reduced with ultralow-dose [18F]FDG total-body PET/CT imaging.
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Fluordesoxiglucose F18 , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Estudos Prospectivos , Estudos de Viabilidade , Tomografia Computadorizada por Raios X , Tomografia por Emissão de Pósitrons/métodosRESUMO
Objective: To investigate the biodistribution and kinetic constants of 68Ga-DOTATATE in normal organs through dynamic total-body positron emission tomography/computed tomography (PET/CT). Methods: Seven patients who experienced endoscopic resection of gastric neuroendocrine tumor were enrolled. Dynamic total-body PET/CT scans over 60 min were performed. Time-activity curves were obtained by drawing regions of interest in normal organs. Rate constants, including K 1, k 2, k 3, and vB, were computed using a two-tissue compartment model. Factor analysis was used to compare the rate constants among subjects and regions. Hierarchical cluster analysis was performed to identify organs with similar kinetic characteristics. Results: The highest uptake of 68Ga-DOTATATE was observed in the spleen followed by kidneys, adrenals, liver, pituitary gland, pancreas head, prostate, pancreas body, and thyroid, parotid, and submandibular glands. Low background level of 68Ga-DOTATATE uptake was observed in the nasal mucosa, bone, blood pool, and cerebrum. In addition, the uptake in the pancreas head was noted to be higher than the pancreas body (P < 0.001) on the basis of each time point of dynamic PET. There were differences of rate constants among different organs. The mean K 1 ranged from 0.0507 min-1 in the left nasal mucosa to 1.21 min-1 in the left kidney, and mean k 2 ranged from 0.0174 min-1 in the spleen to 4.4487 min-1 in the left cerebrum. The mean k 3 ranged from 0.0563 min-1 in the right cerebrum to 4.6309 min-1 in the left adrenal, and mean vB ranged from 0.0001 in the left cerebrum to 0.2489 in the right adrenal. However, none of the rate constants was significantly different among subjects or among different sites within a single organ. Three groups of organs with similar kinetic characteristics were identified: (1) cerebrum; (2) pituitary gland, liver, adrenal, and prostate; and (3) nasal mucosa, parotid and submandibular glands, thyroid, spleen, pancreas, kidney, and bone. Conclusion: Uptake and clearance of 68Ga-DOTATATE, in terms of kinetic constants, were different in different organs. The kinetic parameters of 68Ga-DOTATATE in different organs provide a reference for future dynamic PET imaging.
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Compostos Organometálicos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Masculino , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Radioisótopos de Gálio , Distribuição Tecidual , Tomografia por Emissão de Pósitrons/métodosRESUMO
OBJECTIVE: To compare the diagnostic performance of 18F-FDG PET/MR and PET/CT preliminarily for the thoracic staging of non-small cell lung cancer (NSCLC) with a special focus on pleural invasion evaluation. METHODS: 52 patients with pathologically confirmed NSCLC were included and followed for another year. Whole-body 18F-FDG PET/CT and subsequent thoracic PET/MR were performed for initial thoracic staging. Thoracic (simultaneous) PET/MR acquired PET images and MRI sequences including T2 weighted imaging, with and without fat saturation, T1 weighted imaging, and diffusion weighted imaging (DWI). Two radiologists independently assessed the thoracic T, N staging and pleural involvement. The McNemar Chi-square test was used to compare the differences between PET/CT and PET/MR in the criteria. The area under the receiver-operating-characteristic curves (AUC) was calculated. RESULTS: Compared to PET/CT, PET/MR exhibited higher sensitivity, specificity in the detection of pleural invasion; 82 % vs. 64% (pâ¯=â¯0.625), 98 % vs. 95% (pâ¯=â¯1.000), PET/MR to PET/CT respectively. The receiver-operating-characteristic analysis results of PET/CT vs PET/MR for the pleural invasion were as follow: AUCPET/CTâ¯=â¯0.79, AUCPET/MRâ¯=â¯0.90, pâ¯=â¯0.21. Both T staging results and N staging results were approximately identical in PET/CT and PET/MR. Differences between PET/CT and PET/MR in T staging, N staging as well as pleural invasion accuracy were not statistically significant (pâ¯>â¯0.05, each). CONCLUSION: PET/MR and PET/CT demonstrated equivalent performance about the evaluation of preoperative thoracic staging of NSCLC patients. PET/MR may have greater potential in pleural invasion evaluation for NSCLC, especially for solid nodules, crucial to clinical decision-making, though our results did not demonstrate statistical significance.
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Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Carcinoma Pulmonar de Células não Pequenas/patologia , Fluordesoxiglucose F18 , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Neoplasias Pulmonares/patologia , Tomografia Computadorizada por Raios X/métodos , Estadiamento de Neoplasias , Imageamento por Ressonância MagnéticaRESUMO
PURPOSE: The purpose of this study was to investigate image quality and lesion detectability of half-dose (1.85 MBq/kg) 18 F-fluorodeoxyglucose (FDG) total-body positron emission tomography/computed tomography (PET/CT) for colorectal cancer, full-dose (3.7 MBq/kg) 18 F-FDG serving as a reference. METHODS: Fifty patients confirmed to have colorectal cancer who underwent total-body PET/CT with half-dose 18 F-FDG were included. Another 50 colorectal cancer patients with 3.70 MBq/kg 18 F-FDG activity were selected for the full-dose group. PET images in the half-dose group were scanned for 15 min and split into 1-, 2-, 3-, 4- and 10-min duration groups, denoted G1, G2, G3, G4 and G10, respectively. In the full-dose group, PET scanning was performed for 5 min, reconstructed with the first 0.5, 1, 2 and 5 min intervals, defined as G0.5', G1', G2' and G5', respectively. Subjective image quality was assessed with 5-point Likert scales. Objective image quality parameters included maximum standardized uptake values (SUV max) , mean standardized uptake values (SUV mean )and signal-to-noise ratio (SNR) of the liver, blood pool and muscle and SUV max and tumor-to-background ratio (TBR) of lesions. RESULTS: In the two groups, the G3 and G2' images met clinical diagnosis requirements in terms of subjective image quality, with scores ≥3. There were no differences in terms of subjective and objective image quality between the groups (G1 and G0.5', G2 and G1', G4 and G2' and G10 and G5'). In the half-dose group, 56 colorectal lesions in 50 patients confirmed by surgical pathology were clearly visible in all groups. The number of FDG-avid lymph nodes was 37 in G1, 38 in G2 and 39 in the remaining half-dose groups. The number of missed metastatic liver lesions was 1 both in G1 and G2. CONCLUSIONS: Total-body PET/CT with half-dose was feasible for diagnosing and staging colorectal cancer compared with full-dose 18 F-FDG PET/CT. Moreover, for half-dose total-body PET/CT, a 3-min scan duration could maintain image quality and lesion detectability.
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Neoplasias Colorretais , Fluordesoxiglucose F18 , Neoplasias Colorretais/diagnóstico por imagem , Humanos , Estadiamento de Neoplasias , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Tomografia por Emissão de Pósitrons/métodos , Compostos RadiofarmacêuticosRESUMO
Retraction phenomenon is a unique sign on an automated breast volume scanner coronal plane image and has high specificity in differentiating benign lesions from malignant breast cancer. The purpose of this study was to quantify the retraction phenomenon by setting different rules to describe connected regions from different dimensions. In total, six quantitative indicators (FΩ1,FΓ,FS,FΩ2,FΩ3and FL) were obtained. FΩ1, FΩ2 and FΩ3 represent the relative areas of the connected region under different rules. FΓandFS represent the number ratio and absolute area of the connected region, respectively. FL represents the ratio of edge numbers. Two hundred fourteen patients with 214 lesions (90 benign and 124 malignant) were enrolled in this study. All quantitative indicators in the malignant group were significantly higher than those in the benign group (all p values <0.001). The indicator FΓ achieved the highest area under the receiver operating characteristic curve (AUC) (0.701, 95% confidence interval: 0.631-0.771). Both FΓ and FS had significant associations with axillary lymph node metastasis (p = 0.023 and 0.049). Compared with the classic texture feature gray-level co-occurrence matrix, retraction phenomenon quantization improved the AUC by 8.3%. The results indicate that retraction phenomenon quantitative indicators have certain value in distinguishing benign and malignant breast lesions and seem to be associated with axillary lymph node metastasis.
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Neoplasias da Mama , Interpretação de Imagem Assistida por Computador , Mama/diagnóstico por imagem , Mama/patologia , Neoplasias da Mama/patologia , Diagnóstico Diferencial , Feminino , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Metástase Linfática/patologia , Prognóstico , Curva ROC , Sensibilidade e EspecificidadeRESUMO
PURPOSE: This study was to evaluate the effects of an ultra-low dose of [18F]-FDG on the image quality of total-body PET/CT and its lesion detectability in colorectal cancer (CRC). METHODS: Sixty-two CRC patients who underwent total-body PET/CT (uEXPLORER, United Imaging Healthcare, Shanghai, China) with an ultra-low dose (0.37 MBq/kg) of [18F]-FDG were enrolled in this retrospective study. The PET images were reconstructed with the entire 15-min dataset first and then split into 13-, 8-, 5-, 4-, 3-, 2-, and 1-min duration groups to simulate fast scanning images. For simplicity, the images reconstructed with the data from 15 to 1 min were referred to as G15, G13, and so on until G1. Subjective image quality was assessed with 5-point Likert scales. The objective image quality parameters included the SUVmax, SUVmean, and signal-to-noise ratio (SNR) of the liver and blood pool and the SUVmax and tumor-to-background ratio (TBR) of the lesions. G15 served as the control to evaluate lesion detectability. RESULTS: A total of 62 patients (43 men, 19 women; age 41-88, mean ± SD 64.0 ± 10.9 years) with 64 CRC primary tumor lesions and 10 low-grade intraepithelial neoplasia (LGIN) lesions were enrolled in this study. The subjective scores were highest for G15 (4.5 ± 0.5) and then decreased from G13 (4.3 ± 0.4) to G8 (3.7 ± 0.5). The liver SNR increased with the extension of acquisition time from G8 (17.2 ± 2.8) to G13 (20.6 ± 3.4) and G15 (21.9 ± 3.4). The liver SNR of G8 was not significantly different from that of G13 (p = 0.15) and was significantly different from that of G15 (p = 0.001). All 64 CRC lesions could be identified in all image groups, even on G1. One of ten LGINs was missed on G1, G2, and G3, and one LGIN was missed on G1, G2, G3, and G4. G15 served as the control, and 100% (48/48) lymph nodes could be found on G13 and G8 compared to 93.8% (45/48) lymph nodes on G5 and G4, 85.4% (41/48) lymph nodes on G3, 81.3% (39/48) lymph nodes on G2, and 77.1% (37/48) lymph nodes on G1. For liver metastases, there were no missed liver lesions on G13 and G8 and 3, 4, 6, 7, and 9 missed liver lesions on G5, G4, G3, G2, and G1, respectively. For other areas of metastasis, including the lung, peritoneum, and ovaries, there were no missed lesions in any group. CONCLUSIONS: Total-body PET/CT with an ultra-low dose of [18F]-FDG can maintain satisfactory image quality and lesion detectability in CRC.
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Neoplasias Colorretais , Neoplasias Hepáticas , Adulto , Idoso , Idoso de 80 Anos ou mais , China , Neoplasias Colorretais/diagnóstico por imagem , Feminino , Fluordesoxiglucose F18 , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodosRESUMO
BACKGROUND: Considering the few reported cardiac masses, PET/CT in the imaging workup of cardiac masses is not well established. This retrospective study analyzed the role of 18F-FDG PET/CT imaging in cardiac/pericardial masses. METHODS AND RESULTS: Fifty-nine patients with newly diagnosed cardiac/pericardial masses who underwent PET/CT and transthoracic echocardiography (TTE) were recruited. Echocardiographic and PET/CT characteristics were evaluated for predictive value in differentiating malignant and non-malignant lesions using histologic confirmation as the gold standard. The McNemar test was used to test the differences in sensitivity between PET/CT and TTE. 18F-FDG PET/CT had higher sensitivity in determining the malignancy of cardiac/pericardial masses compared to TTE (sensitivity, 96.6% vs 72.4%, P = .039). However, when pericardial masses were excluded from the analysis, the difference in sensitivity between the two was not statistically significant (sensitivity, 95.6% vs 78.3%, P = .219). 18F-FDG PET/CT identified two malignant pericardial masses missed on TTE, changed the diagnostic orientation of TTE in 15 patients, and found seven patients with extracardiac lesions in 29 malignant patients. CONCLUSIONS: PET/CT was an effective additional image modality in patients with suspected malignant cardiac mass for further confirmation and to screen for potential metastasis.
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Fluordesoxiglucose F18 , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Coração , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Tomografia por Emissão de Pósitrons , Estudos RetrospectivosRESUMO
PURPOSE: The aim of this study is to investigate the value of pre-treatment 18F-FDG PET/CT in predicting the pathological characteristic of HCC and recurrence after liver transplantation (LT). METHODS: A total of 34 patients who underwent 18F-FDG PET/CT before LT for HCC and did not receive any other treatment were retrospectively enrolled in the study. The maximal standard uptake value of the tumor (T-SUVmax), normal liver tissues (L-SUVmax), and mediastinal blood pool (B-SUVmax) were derived, followed by the calculations of the T-SUVmax/L-SUVmax (T/L) and the T-SUVmax/B-SUVmax (T/B) ratios. Combined with the post-transplantation pathological results and ROC curve, the performance in predicting the pathological characteristic and the recurrence after LT were evaluated. RESULTS: The AUCs for T-SUVmax, T/L, and T/B in predicting the pathological grade of tumors were 0.820, 0.784, and 0.806, respectively. Alternatively, the AUCs for T-SUVmax, T/L, and T/B in predicting the recurrence after LT were 0.865, 0.899, and 0.931, respectively. The individual cutoff values were 5.0, 1.7, and 2.2, corresponding to a predication accuracy of 88.2%, 85.3%, and 88.2%, respectively. In addition, the AUCs for T/B in predicting microvascular invasion (mVI) and liver capsular invasion (LCI) were 0.825 and 0.788, respectively. CONCLUSION: The pre-treatment 18F-FDG PET/CT is effective for predicting recurrence of HCC after LT. In addition, it demonstrates values for predicting the pathological characteristic of HCC such as pathological grade, mVI, and LCI.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Transplante de Fígado , Carcinoma Hepatocelular/diagnóstico por imagem , Carcinoma Hepatocelular/cirurgia , Fluordesoxiglucose F18 , Humanos , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/cirurgia , Recidiva Local de Neoplasia/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos , Estudos RetrospectivosRESUMO
This study aimed to dynamically monitor myocardial cell death using 99m Tc-Duramycin single-photon emission computed tomography/computed tomography (micro-SPECT/CT) imaging in acute myocardial infarction (AMI) and the anti-apoptosis effect of atorvastatin for cardioprotection. Mice were randomized into three groups: AMI group, AMI with atorvastatin treatment (T-AMI) group, and sham group. Three groups of model mice were randomly selected at day 1 (D1), day 3 (D3), and day 7 (D7) day after surgery with 99m Tc-Duramycin micro-SPECT/CT imaging. The lesion-to-normal myocardial tissue ratio (L/N) average values were 2.62 on D1, 3.89 on D3, and 1.20 on D7 for the uptake of 99m Tc-duramycin in the infarcted region in the AMI group. The sham group presented no positive imaging in myocardium, and the L/N average values were 1.09, 1.14, and 1.10 on D1, D3, and D7, respectively. Meanwhile, 99m Tc-linear-duramycin imaging showed no radioactive uptake in the infarction region. The T-AMI group imaging showed tracer uptake decreased obviously compared to the uptake in the infarcted region in AMI mice. 99m Tc-Duramycin SPECT/CT imaging allowed non-invasive monitoring of myocardial cell death in a mouse model of AMI and an assessment of atorvastatin anti-apoptosis effect for cardioprotection by in vivo molecular imaging.
Assuntos
Apoptose/efeitos dos fármacos , Atorvastatina/farmacologia , Bacteriocinas/química , Cardiotônicos/farmacologia , Infarto do Miocárdio/diagnóstico por imagem , Peptídeos/química , Compostos Radiofarmacêuticos/química , Doença Aguda , Animais , Atorvastatina/uso terapêutico , Bacteriocinas/farmacologia , Cardiotônicos/uso terapêutico , Modelos Animais de Doenças , Camundongos , Infarto do Miocárdio/tratamento farmacológico , Miocárdio/citologia , Miocárdio/metabolismo , Miocárdio/patologia , Peptídeos/farmacologia , Compostos Radiofarmacêuticos/farmacologia , Tomografia Computadorizada com Tomografia Computadorizada de Emissão de Fóton Único , Tecnécio/químicaRESUMO
PURPOSE: The purpose was to explore the effects of total-body PET/CT with half-dose 18F-FDG activity on image quality, compared with those of conventional PET/CT with clinical routine full-dose 18F-FDG in lung cancer. METHODS: Fifty-six primary lung cancer patients who underwent total-body PET/CT on a uEXPLORER scanner with half-dose (1.85 MBq/kg) 18F-FDG activity before treatment were retrospectively studied; among them, 28 patients were confirmed by postoperative pathologic examination and 28 patients by biopsy. After matching with the pathological study results, the other 28 patients with lung cancer who underwent surgery were selected for the full-dose (3.70 MBq/kg) group. Patients in the full-dose group were studied with a conventional uM780 PET/CT scanner. The acquisition time of the half-dose group was 15 min, split into 4-min and 2-min duration groups, which were all referred to as G15, G4 and G2, respectively. The PET/CT scanning speed in the full-dose group was 2 min/bed. Image quality was evaluated by subjective and objective analyses. The subjective analysis method was carried out with a 5-point scale (5-excellent, 1-poor). Objective analysis indicators of PET image quality included the SUVmax, SUVmean and signal-to-noise ratio (SNR) of the liver; the SUVmax and SUVmean of the blood pool; and the SUVmax and tumour-to-background ratio (TBR) of the lesions. G15 served as the reference for G2 and G4 to test lesion detectability. RESULTS: Image quality scores in G2 (4.3 ± 0.7) were significantly higher than those in the full-dose group (3.7 ± 0.6) (p = 0.004). The mean and SD of the image quality scores in G4 and G15 were 4.9 ± 0.2 and 5.0 ± 0.0, respectively. The liver SNR in G2 was significantly higher than that in the full-dose group; the corresponding SNR were 11.7 ± 1.5 and 8.3 ± 1.2 (p < 0.001), respectively. The liver SNR significantly increased with the time of acquisition among G2, G4 and G15 (11.1 ± 1.7, 15.2 ± 3.4 and 30.5 ± 6.0, all p < 0.05). G15 served as the reference, and all these lesions (100%) could be identified by G2 and G4. CONCLUSION: Total-body PET/CT with half-dose 18F-FDG activity in G2 and G4 achieved comparable image quality to conventional PET/CT, and its image quality was better than that of conventional PET/CT with clinical routine full-dose 18F-FDG in lung cancer.
Assuntos
Fluordesoxiglucose F18 , Neoplasias Pulmonares , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Tomografia por Emissão de Pósitrons , Estudos Retrospectivos , Tomografia Computadorizada por Raios XRESUMO
OBJECTIVE. The purpose of this article is to describe the clinical applications of a total-body PET scanner and discuss future expectations. CONCLUSION. PET has been widely used in the fields of oncology, neurology, and cardiology. However, current PET scanners have limitations, including long scanning time, low signal-to-noise ratio, and high dose of ionizing radiation. Total-body PET with a long scan range provides solutions to these problems, markedly increasing the sensitivity of the system.
Assuntos
Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Imagem Corporal Total , Previsões , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/tendências , Imagem Corporal Total/tendênciasRESUMO
PURPOSE: To investigate the added value of dual-time-point 18F-FDG PET/CT imaging in the diagnosis of colorectal cancer liver metastases (CRLM). METHODS: One hundred and eight patients with CRLM preoperatively underwent a dual-time-point 18F-FDG PET/CT scan. All hepatic lesions were diagnosed by histopathology. The diagnostic sensitivity of 18F-FDG PET/CT for CRLM was calculated on early scan and delayed scan, respectively. The McNemar test was used to test the differences of the sensitivity and the specificity between early scan and delayed scan. RESULTS: On a per-patient basis, no significant difference in sensitivity was found between early scan and delayed scan (92.93% vs. 96.97%, P = 0.125). The per-patient specificity of early and delayed scans was 77.78%. On a per-lesion basis, overall sensitivity of delayed scan was significantly higher than that of early scan (83.49% vs. 76.61%, P < 0.001). The per-lesion specificity of early and delayed scans was 69.23%. For the lesion size of CRLM ≤ 10 mm, delayed imaging had significantly higher sensitivity than early imaging (47.17% vs. 26.42%, P < 0.001). However, for CRLM > 10 mm, there was no significant difference in sensitivity between early and delayed scans (92.73% vs. 95.15%, P = 0.125). Of the detected 182 liver metastatic lesions on delayed scan, the SUVmax on delayed scan was significantly higher than that on early scan (12.13 ± 7.13 vs. 9.16 ± 4.74, P < 0.001). The SUVmean of the normal liver on delayed scan was significantly lower than that on early scan (1.91 ± 0.29 vs. 2.33 ± 0.31, P < 0.001). The tumor to normal background ratio on delayed scan was significantly higher than that on early scan (6.59 ± 4.43 vs. 4.02 ± 2.23, P < 0.001). CONCLUSION: The dual-time-point 18F-FDG PET/CT imaging might detect more CRLM lesions compared with single-time-point imaging, especially for small (< 10 mm) lesions.
Assuntos
Neoplasias Colorretais/patologia , Neoplasias Hepáticas/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Fluordesoxiglucose F18 , Humanos , Neoplasias Hepáticas/secundário , Masculino , Pessoa de Meia-Idade , Compostos Radiofarmacêuticos , Estudos Retrospectivos , Sensibilidade e EspecificidadeRESUMO
PURPOSE: The use of antibodies as tracers requires labeling with isotopes with long half-lives due to their slow pharmacokinetics, which creates prohibitively high radiation dose to non-target organs. Pretargeted methodology could avoid the high radiation exposure due to the slow pharmacokinetics of antibodies. In this investigation, we reported the development of a novel pretargeted single photon emission computed tomography (SPECT) imaging strategy (atezolizumab-TCO/[99mTc]HYNIC-PEG11-Tz) for evaluating immune checkpoint ligand PD-L1 expression in tumor based on bioorthogonal Diels-Alder click chemistry. PROCEDURES: The radioligand [99mTc]HYNIC-PEG11-Tz was achieved by the synthesis of a 6-hydrazinonicotinc acid (HYNIC) modified 1,2,4,5-tetrazine (Tz) and subsequently radiolabeled with technetium-99m (Tc-99m). The stability of [99mTc]HYNIC-PEG11-Tz was evaluated in vitro, and its blood pharmacokinetic test was performed in vivo. Atezolizumab was modified with trans-cyclooctene (TCO). The [99mTc]HYNIC-PEG11-Tz and atezolizumab-TCO interaction was tested in vitro. Pretargeted H1975 cell immunoreactivity binding and saturation binding assays were evaluated. Pretargeted biodistribution and SPECT imaging experiments were performed in H1975 and A549 tumor-bearing modal mice to evaluate the PD-L1 expression level. RESULTS: [99mTc]HYNIC-PEG11-Tz was successfully radiosynthesized with a specific activity of 9.25 MBq/µg and a radiochemical purity above 95 % as confirmed by reversed-phase HPLC (RP-HPLC). [99mTc]HYNIC-PEG11-Tz showed favorable stability in NS, PBS, and FBS and rapid blood clearance in mice. The atezolizumab was modified with TCO-NHS ester to produce a conjugate with an average 6.4 TCO moieties as confirmed by liquid chromatograph-mass spectrometer (LC-MS). Size exclusion HPLC revealed almost complete reaction between atezolizumab-TCO and [99mTc]HYNIC-PEG11-Tz in vitro, with the 1:1 Tz-to-mAb reaction providing a conversion yield of 88.65 ± 1.22 %. Pretargeted cell immunoreactivity binding and saturation binding assays showed high affinity to H1975 cells. After allowing 48 h for accumulation of atezolizumab-TCO in H1975 tumor, pretargeted in vivo biodistribution revealed high uptake of the radiotracer in the tumor with a tumor-to-muscle ratio of 27.51 and tumor-to-blood ratio of 1.91. Pretargeted SPECT imaging delineated the H1975 tumor clearly. Pretargeted biodistribution and SPECT imaging in control groups demonstrated a significantly reduced tracer accumulation in the A549 tumor. CONCLUSIONS: We have developed a HYNIC-modified Tz derivative, and the HYNIC-PEG11-Tz was labeled with Tc-99m with a high specific activity and radiochemical purity. [99mTc]HYNIC-PEG11-Tz reacted rapidly and almost completely towards atezolizumab-TCO in vitro with the 1:1 Tz-to-mAb reaction. SPECT imaging using the pretargeted strategy (atezolizumab-TCO/[99mTc]HYNIC-PEG11-Tz) demonstrated high-contrast images for high PD-L1 expression H1975 tumor and a low background accumulation of the probe. The pretargeted imaging strategy is a powerful tool for evaluating PD-L1 expression in xenograft mice tumor models and a potential candidate for translational clinical application.