Positron Emission Tomography And Computed Tomography Research Articles

Computational Techniques in PET/CT Image Processing for Breast Cancer: A Systematic Mapping Review

The problem arises from the lack of sufficient and comprehensive information about the necessary computer techniques. These techniques are crucial for developing information systems that assist doctors in diagnosing breast cancer, especially those related to positron emission tomography and computed tomography (PET/CT). Despite global efforts in breast cancer prevention and control, the scarcity of literature poses an obstacle to a complete understanding in this area of interest. The methodologies studied were systematic mapping and systematic literature review. For each article, the journal, conference, year of publication, dataset, breast cancer characteristics, PET/CT processing techniques, metrics and diagnostic yield results were identified. Sixty-four articles were analyzed, 44 (68.75%) belong to journals and 20 (31.25%) belong to the conference category. A total of 102 techniques were identified, which were distributed in preprocessing with 7 (6.86%), segmentation with 15 (14.71%), feature extraction with 15 (14.71%), and classification with 65 (63.73%). The techniques with the highest incidence identified in each stage are: Gaussian Filter, SLIC, Local Binary Pattern, and Support Vector Machine with 4, 2, 7, and 35 occurrences, respectively. Support Vector Machine is the predominant technique in the classification stage, due to the fact that Artificial Intelligence is emerging in medical image processing and health care to make expert systems increasingly intelligent and obtain favorable results.

Hybrid PET/MRI of large vessel vasculitis : Radiation dose compared to PET/CT with view on cumulative effective dose.

The diagnosis of large vessel vasculitis (LVV) is often challenging due to the various clinical appearances and the low prevalence. Hybrid imaging by positron emission tomography and computed tomography (PET/CT) is ahighly relevant imaging modality for diagnostics and disease surveillance but may be associated with asignificant amount of radiation dose especially in patients with complications. The aim of this retrospective analysis was to compare the image quality and impact of hybrid imaging methods PET/CT and PET/MRI on the potential for dose reduction. This retrospective single-center study included acohort of 32patients who were referred to PET/MRI for the evaluation of LVV, including graft infections and fever of unknown origin. This cohort was compared to asimilar cohort of 37patients who were examined with PET/CT in the same period. Mean radiation dose as well as image quality to establish adiagnosis were compared between the groups. The mean radiation dose applied in PET/MRI was significantly lower when compared to PET/CT (mean 6.6 mSV vs. 31.7 mSV; p < 0.001). This effect was based on the partially multiphasic CT protocols. At the same time, diagnostic image quality using a4-point scale showed similar results for both imaging modalities in the work-up of LVV. With PET/MRI, the radiation exposure can be significantly reduced with similar image quality and diagnostic impact. Patients with LVV have ahigher risk of receiving aclinically relevant cumulative effective dose (CED) and PET/MRI should be made available to them.

Deep learning radiomics model based on PET/CT predicts PD-L1 expression in non-small cell lung cancer

PurposeProgrammed cell death protein-1 ligand (PD-L1) is an important prognostic predictor for immunotherapy of non-small cell lung cancer (NSCLC). This study aimed to develop a non-invasive deep learning and radiomics model based on positron emission tomography and computed tomography (PET/CT) to predict PD-L1 expression in NSCLC. MethodsA total of 136 patients with NSCLC between January 2021 and September 2022 were enrolled in this study. The patients were randomly divided into the training dataset and the validation dataset in a ratio of 7:3. Radiomics feature and deep learning feature were extracted from their PET/CT images. The Mann-whitney U-test, Least Absolute Shrinkage and Selection Operator algorithm and Spearman correlation analysis were used to select the top significant features. Then we developed a radiomics model, a deep learning model, and a fusion model based on the selected features. The performance of three models were compared by the area under the curve (AUC), sensitivity, specificity, accuracy, positive predictive value, and negative predictive value. ResultsOf the patients, 42 patients were PD-L1 negative and 94 patients were PD-L1 positive. A total of 2446 radiomics features and 4096 deep learning features were extracted per patient. In the training dataset, the fusion model achieved a highest AUC (0.954, 95% confident internal [CI]: 0.890–0.986) compared with the radiomics model (0.829, 95%CI: 0.738–0.898) and the deep learning model (0.935, 95%CI: 0.865–0.975). In the validation dataset, the AUC of the fusion model (0.910, 95% CI: 0.779–0.977) was also higher than that of the radiomics model (0.785, 95% CI: 0.628–0.897) and the deep learning model (0.867, 95% CI: 0.724–0.952). ConclusionThe PET/CT-based deep learning radiomics model can predict the PD-L1 expression accurately in NSCLC patients, and provides a non-invasive tool for clinicians to select positive PD-L1 patients.

Anti-PD-1 Antibody (Tislelizumab) Combined with R-CHOP for the Treatment of Previously Untreated Primary Mediastinal B-Cell Lymphoma: A Prospective Phase II Study

Background: Primary mediastinal B-cell lymphoma (PMBCL) is a rare aggressive B-cell lymphoma of thymic origin. Due to the low incidence rate of PMBCL, there is currently no internationally accepted standard first-line treatment regimen. Dose-adjusted (DA) EPOCH-R which is the more commonly used first-line therapy plan is not so effective because patients usually cannot tolerate it. The R-CHOP regimen is comparable to the R-DA-EPOCH for the first-line treatment of PMBCL in terms of survival and has a better safety profile (Bhatt, V.R. et al, Cancer Treat Rev 2015; Iwanicka el al., Curr Hematol Malig Rep 2014). Meanwhile, patients with PMBCL usually have alterations of 9p24.1, leading to overexpression of PDL-1/2. Previous studies have found that PD-1 monoclonal antibody shows good efficacy in recurrent and refractory PMBCL (Steidl et al., Blood 2011; Zinzani et al., Blood 2017). Tislelizumab, a humanized IgG4 antibody that binds PD-1 with high affinity, minimizes binding to Fcγ receptor 1 (FcγRI) on macrophages by the genetic engineering of Fc segment, abrogating antibody-dependent phagocytosis (ADCP)-induced T-cell clearance. The efficacy and safety of its combination with R-CHOP in previously untreated PMBCL is not yet clear. We speculate that the combination of both may be a new option for the first-line therapy for PMBCL patients with good efficacy and low toxicity. Methods: This is a single-arm, multi-center, phase II clinical study (ChiCTR2100044313). Patients aged 18 years or older with a diagnosis of PMBCL and previously untreated were eligible. Eligible patients received 6 cycles of Tislelizumab (200 mg D1), Rituximab (375 mg/m 2 D1), Cyclophosphamide (750 mg/m 2 D2), Pirarubicin (50 mg/m 2 D2), Vincristine (1.4 mg/m 2, maximum dose 2 mg, D2), Prednisone (100 mg/d D2-6), every 21 days for 1 cycle. Disease response assessments were performed by positron emission tomography and computed tomography (PET-CT) or enhanced CT every two cycles, meanwhile peripheral blood ctDNA was monitored, and treatment-related adverse effects were assessed and recorded. The primary endpoint was objective remission rate (ORR). The secondary endpoints included treatment safety, progression-free survival (PFS) and overall survival (OS), and the exploratory analyses of the correlation between PD-L1 expression in tumor tissues, tumor-associated macrophages (TAM) phenotype in tumor microenvironment and efficacy. Results: From June 2020 to June 2023, 12 patients were enrolled and 9 patients had evaluable efficacy with the median age of 34 years, 3 males and 6 females, all patients had large mediastinal mass at initial diagnosis. 7 patients had PD-L1 expression (VENTANA SP263) above 80% and 2 cases could not be further tested due to insufficient tissue specimens. The ORR was 100%, and the CR rate was 77.8% (7/9) after 6 cycles of treatment. The 5 th and 9 th patient reached PR after 6 cycles of treatment due to irregular hospitalization. And CR was achieved after 2 cycles of regular treatment for the 5 th patient. NGS from formalin-fixed paraffin-embedded (FFPE) and circulating tumor DNA (ctDNA) evaluation from blood were performed across all patients before treatment. 5 patients underwent end of treatment-ctDNA test. Median follow-up 15m (6.8m-26.3m), the third patient was lost to follow-up at 9m. The other patients who achieved CR are still at complete remission. Moreover, we found SOCS1, TNFAIP3 are the most frequently mutated genes in biopsies of PMBCL and only the 5th patient had RHOA mutation which is highly related to PMBCL. The PET-CT and ctDNA assessments were negative in three patients at the end of 6 cycles with 60% concordance, and the 5 th and 9 th patient achieved PR on PET-CT, but the ctDNA assessments were negative. The most common adverse events (AEs) were gastrointestinal reactions, 2 patients experienced grade IV myelosuppression and 1 patient had grade I hyperthyroidism. No treatment-related deaths occurred. Conclusion: Tislelizumab combined with R-CHOP for the treatment of previously untreated PMBCL had good efficacy and sustained response with low toxicity. Longer follow-up is required to access the survival benefit of this regimen. Figure 1: Disease Remission in the Included Patients

Accumulation of endogenous adenosine improves cardiomyocyte metabolism via epigenetic reprogramming in an ischemia-reperfusion model

Adenosine kinase (ADK) plays the major role in cardiac adenosine metabolism, so that inhibition of ADK increases myocardial adenosine levels. While the cardioprotective actions of extracellular adenosine against ischemia/reperfusion (I/R) are well-established, the role of cellular adenosine in protection against I/R remains unknown. Here we investigated the role of cellular adenosine in epigenetic regulation on cardiomyocyte gene expression, glucose metabolism and tolerance to I/R. Evans blue/TTC staining and echocardiography were used to assess the extent of I/R injury in mice. Glucose metabolism was evaluated by positron emission tomography and computed tomography (PET/CT). Methylated DNA immunoprecipitation (MeDIP) and bisulfite sequencing PCR (BSP) were used to evaluate DNA methylation. Lentiviral/adenovirus transduction was used to overexpress DNMT1, and the OSI-906 was administered to inhibit IGF-1. Cardiomyocyte-specific ADK/IGF-1-knockout mice were used for mechanistic experiments.Cardiomyocyte-specific ADK knockout enhanced glucose metabolism and ameliorated myocardial I/R injury in vivo. Mechanistically, ADK deletion caused cellular adenosine accumulation, decreased DNA methyltransferase 1 (DNMT1) expression and caused hypomethylation of multiple metabolic genes, including insulin growth factor 1 (IGF-1). DNMT1 overexpression abrogated these beneficial effects by enhancing apoptosis and decreasing IGF-1 expression. Inhibition of IGF-1 signaling with OSI-906 or genetic knocking down of IGF-1 also abrogated the cardioprotective effects of ADK knockout, revealing the therapeutic potential of increasing IGF-1 expression in attenuating myocardial I/R injury. In conclusion, the present study demonstrated that cardiomyocyte ADK deletion ameliorates myocardial I/R injury via epigenetic upregulation of IGF-1 expression via the cardiomyocyte adenosine/DNMT1/IGF-1 axis.

Comparison of SUVA/V and SUVA-V for Evaluating Atherosclerotic Inflammation in 18F-FDG PET/CT.

This study aimed to compare the clinical significance of two parameters, division of standardized uptake value (SUV) of target arterial activity by background venous blood pool activity (SUVA/V) and subtraction of background venous blood pool activity from SUV of target arterial activity (SUVA-V) of carotid arteries with atherosclerotic plaques using 18F-fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (PET/CT). Patients aged 50 years or more who were diagnosed with carotid artery stenosis of 50% or more with carotid Doppler ultrasonography and had torso 18F-FDG PET/CT were enrolled retrospectively and classified patients who developed cerebrovascular events (CVEs) within 5 years after 18F-FDG PET/CT scan as the active group and patients who did not experience the CVE within 5 years as an inactive group. We calculated SUVA/V and SUVA-V using measurements of SUVmax of carotid arteries and mean SUV of superior vena cava (SVC). SUVA-V, SUVA-V_high, and SUVA-V_low were significantly higher in the active group than in the inactive group, but neither SUVA/V, SUVA/V_high, nor SUVA/V_low showed significant differences between the active and inactive groups. The difference in rank between groups of SUVA/V_high and SUVA/V_low was greater than the difference in rank between groups of SUVA-V_high and SUVA-V_low. The CVE incidence differed between SUVA/V_high and SUVA/V_low of high carotid FDG uptake, but the CVE incidence did not differ between SUVA-V_high and SUVA-V_low of high carotid FDG uptake. SUVA-V may be a more rational solution than SUVA/V for evaluating atherosclerotic plaque inflammation on 18F-FDG PET/CT.

Measurable Residual Disease Testing in Multiple Myeloma Routine Clinical Practice: A Modified Delphi Study.

We used a modified Delphi approach to establish areas of consensus and nonconsensus regarding the utility of determining measurable residual disease (MRD) to assess multiple myeloma (MM) treatment response, which may inform disease management and design of future clinical trials. This modified Delphi study incorporated 2 iterative rounds of surveys to evaluate the opinions of an expert panel of 61 practicing hematological oncologists from across 14 countries in Europe concerning the use of MRD testing in MM management. Survey 1 assessed experts' opinions on MRD testing in different clinical situations and associated challenges. Survey 2 focused on the lack of consensus areas identified in survey 1. Consensus to an individual question was defined a priori as 75% agreement or disagreement by the panel. From the 2 rounds of surveys, the experts reached consensus agreement that MRD testing should be performed in newly diagnosed or relapsed patients who achieved complete response (CR) or better after transplantation. In transplant-ineligible patients, experts recommended MRD testing in those who are ≤70 years old and in CR. If a patient was previously positive on positron-emission tomography and computed tomography (PET/CT), both MRD and PET/CT should be assessed at CR. MRD testing should be performed ≤6 months after transplantation and every 6-12 months in continuously treated patients in CR. There was no consensus on making treatment decisions based on MRD status. MRD testing is an important component of clinical management in MM. Additional data will further clarify the role of MRD in guiding treatment decisions.

The Evolving Treatment Landscape of Merkel Cell Carcinoma.

Merkel cell carcinoma (MCC) has a high risk of recurrence and requires unique treatment relative to other skin cancers. The patient population is generally older, with comorbidities. Multidisciplinary and personalized care is therefore paramount, based on patient preferences regarding risks and benefits. Positron emission tomography and computed tomography (PET-CT) is the most sensitive staging modality and reveals clinically occult disease in ~ 16% of patients. Discovery of occult disease spread markedly alters management. Newly diagnosed, localized disease is often managed with sentinel lymph node biopsy (SLNB), local excision, primary wound closure, and post-operative radiation therapy (PORT). In contrast, metastatic disease is usually treated systemically with an immune checkpoint inhibitor (ICI). However, one or more of these approaches may not be indicated. Criteria for such exceptions and alternative approaches will be discussed. Because MCC recurs in 40% of patients and early detection/treatment of advanced disease is advantageous, close surveillance is recommended. Given that over 90% of initial recurrences arise within 3years, surveillance frequency can be rapidly decreased after this high-risk period. Patient-specific assessment of risk is important because recurrence risk varies widely (15 to > 80%: Merkelcell.org/recur) depending on baseline patient characteristics and time since treatment. Blood-based surveillance tests are now available (Merkel cell polyomavirus (MCPyV) antibodies and circulating tumor DNA (ctDNA)) with excellent sensitivity that can spare patients from contrast dye, radioactivity, and travel to a cancer imaging facility. If recurrent disease is locoregional, management with surgery and/or RT is typically indicated. ICIs are now the first line for systemic/advanced MCC, with objective response rates (ORRs) exceeding 50%. Cytotoxic chemotherapy is sometimes used for debulking disease or in patients who cannot tolerate ICI. ICI-refractory disease is the major problem faced by this field. Fortunately, numerous promising therapies are on the horizon to address this clinical need.

Human brown adipose tissue function: insights from current in vivo techniques.

The identification of brown adipose tissue (BAT) as a thermogenic organ in human adults approximately 20 years ago raised the exciting possibility of activating this tissue as a new treatment for obesity and cardiometabolic disease. 18Fluoro-2-deoxyglucose (18F-FDG) combined positron emission tomography and computed tomography (PET/CT) scanning is the most commonly used imaging modality to detect and quantify human BAT activity in vivo. This technique exploits the substantial glucose uptake by BAT during thermogenesis as a marker for BAT metabolism. 18F-FDG PET has provided substantial insights into human BAT physiology, including its regulatory pathways and the effect of obesity and cardiometabolic disease on BAT function. The use of alternative PET tracers and the development of novel techniques such as magnetic resonance imaging, supraclavicular skin temperature measurements, contrast enhanced ultrasound, near infrared spectroscopy and microdialysis have all added complementary information to improve our understanding of human BAT. However, many questions surrounding BAT physiology remains unanswered, highlighting the need for further research and novel approaches to investigate this tissue. This review critically discusses current techniques to assess human BAT function in vivo, the insights gained from these modalities and their limitations. We also discuss other promising techniques in development that will help dissect the pathways regulating human thermogenesis and determine the therapeutic potential of BAT activation.

Diagnostic value of18F-fluorodeoxyglucose positron emission tomography andcomputed tomography fordifferentiating polymyalgia rheumatica andrheumatoid arthritis: Using classification andregression tree analysis.

Determining which sites were important to differentiate polymyalgia rheumatica (PMR) from rheumatoid arthritis (RA) using 18F-fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (PET-CT) is challenging. Patients with PMR or RA who were undergoing PET-CT were recruited at two mutual-aid hospitals in Japan between 2009 and 2018. Classification and regression tree (CART) analyses were performed to identify FDG uptake patterns that differentiated PMR from RA. We enrolled 35 patients with PMR and 46 patients with RA. Univariate CART analysis showed that FDG uptake in the shoulder joints, spinous processes of the lumbar vertebrae, pubic symphysis, sternoclavicular joints, ischial tuberosities, greater trochanters, and hip joints differentiated PMR from RA. Multivariate CART analysis revealed that FDG uptake by at least one of the ischial tuberosities had the highest diagnostic value for distinguishing PMR from RA (sensitivity, 77.1%; specificity, 82.6%). We performed the same CART analysis to patients who had not undergone treatment (PMR, n = 28; RA, n = 9). Similar results were obtained, and sensitivity and specificity were increased (sensitivity, 89.3%; specificity, 88.8%). In PET-CT, FDG uptake by at least one of the ischial tuberosities best discriminates between PMR and RA.

18F-FMISO PET-guided dose escalation with multifield optimization intensity-modulated proton therapy in nasopharyngeal carcinoma.

The purpose of this study was to evaluate the radiotherapy planning feasibility of dose escalation with intensity-modulated proton therapy (IMPT) to hypoxic tumor regions identified on 18F-Fluoromisonidazole (FMISO) positron emission tomography and computed tomography (PET-CT) in NPC. Nine patients with stages T3-4N0-3M0 NPC underwent 18F-FMISO PET-CT before and during week 3 of radiotherapy. The hypoxic volume (GTVhypo) is automatically generated by applying a subthresholding algorithm within the gross tumor volume (GTV) with a tumor to muscle standardized uptake value (SUV) ratio of 1.3 on the 18F-FMISO PET-CT scan. Two proton plans were generated for each patient, a standard plan to 70Gy and dose escalation plan with upfront boost followed by standard 70GyE plan. The stereotactic boost was planned with single-field uniform dose optimization using two fields to deliver 10 GyE in two fractions to GTVhypo. The standard plan was generated with IMPT with robust optimization to deliver 70GyE, 60GyE in 33 fractions using simultaneous integrated boost technique. A plan sum was generated for assessment. Eight of nine patients showed tumor hypoxia on the baseline 18F-FMISO PET-CT scan. The mean hypoxic tumor volume was 3.9 cm3 (range .9-11.9cm3 ). The average SUVmax of the hypoxic volume was 2.2 (range 1.44-2.98). All the dose-volume parameters met the planning objectives for target coverage. Dose escalation was not feasible in three of eight patients as the D0.03cc of temporal lobe was greater than 75GyE. The utility of boost to the hypoxic volume before standard course of radiotherapy with IMPT is dosimetrically feasible in selected patients. Clinical trials are warranted to determine the clinical outcomes of this approach.

Diffuse Large B-Cell Lymphoma and Related Entities.

Diffuse large B-cell lymphoma (DLBCL) is the most common malignant B-cell neoplasm, with an incidence of 5.6 per 100 000 persons per year and a mean age of onset of approximately 65 years. It is an aggressive type of non-Hodgkin's lymphoma requiring urgent treatment with curative intent. Evidence-based guidelines have not been available to date. For this first international evidence-based DLBCL-specific guideline, various systematic literature searches were performed. 5 systematic reviews, 21 randomized controlled trials (RCTs), and 36 non-randomized studies were used to formulate 42 recommendations. 142 were formulated on the basis of expert consensus. All recommendations were approved in a structured consensus-finding process. For staging, combined positron emission tomography and computed tomography (PET/CT) should be performed (evidence: a prospective registry study). For all patients with a new diagnosis of DLBCL and without contraindications, R-CHOP based immunochemotherapy (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) should be initiated with curative intent (evidence: RCTs). The individual treatment strategy is tailored to the patient's age and risk constellation. Once immunochemotherapy has been completed, PET/CT should be performed again to check for remission. Patients with PET-positive residual disease that is amenable to radiotherapy should be treated with consolidating irradiation (evidence: retrospective cohort study). This clinical practice guideline on the diagnosis, treatment, and followup of patients with DLBCL and related entities provides a standardized clinical management approach, identifies areas where improvement would be desirable, and can serve as a basis for the development of further studies.

Adaptive Positron Emission Tomography Radiation Therapy in Patients With Locally Advanced Vulvar Cancer: A Prospective Study

In this prospective trial, we aim to determine whether fluorodeoxyglucose positron emission tomography and computed tomography (PET/CT)-based adaptive radiation therapy (ART) improves dosimetry outcomes for patients treated with definitive radiation for locally advanced vulvar cancer. Patients were enrolled in 2 sequential institutional review board-approved prospective protocols for PET/CT ART from 2012 to 2020. Patients were planned with pretreatment PET/CT to 45 to 56 Gy in 1.8 Gy/fraction, followed by a boost to gross disease (nodal and/or primary) to a total of 64 to 66 Gy. Intratreatment PET/CT was obtained at 30 to 36 Gy, and all patients were replanned to the same dose goals with revised organ at risk (OAR), gross tumor volume, and planned target volume contours. Radiation therapy consisted of either intensity modulated radiation therapy or volumetric modulated arc therapy. Toxicity was graded by Common Terminology Criteria for Adverse Events, version 5.0. Local control, disease-free survival, overall survival, and time to toxicity were estimated using the Kaplan-Meier method. Dosimetry metrics for OARs were compared using the Wilcoxon signed rank test. Twenty patients were eligible for analysis. Median follow-up among surviving patients was 5.5 years. Local control, disease-free survival, and overall survival at 2 years were 63%, 43%, and 68%, respectively. ART significantly reduced the following OAR doses: bladder, maximum dose (Dmax; median reduction [MR], 1.1 Gy; interquartile range [IQR], 0.48-2.3 Gy; P < .001) and D2cc (MR, 1.5 Gy; IQR, 0.51-2.1 Gy; P < .001); bowel, Dmax (MR, 1.0 Gy; IQR, 0.11-2.9 Gy; P < .001), D2cc (MR, 0.39 Gy; IQR, 0.023-1.7 Gy; P < .001), and D15cc (MR, 0.19 Gy; IQR, 0.026-0.47 Gy; P=.002); and rectal, mean dose (MR, 0.66 Gy; IQR, 0.17-1.7 Gy; P=.006) and D2cc (MR, 0.46 Gy; IQR, 0.17-0.80 Gy; P=.006). No patients experienced any grade ≥3 acute toxicities. There were no reported late grade ≥2 vaginal toxicities. Lymphedema at 2 years was 17% (95% confidence interval, 0%-34%). Doses to bladder, bowel, and rectum were significantly improved with ART, though the median magnitudes were modest. Which patients benefit most from adaptive treatment is a matter for future investigation.

PET/CT standardized uptake value and EGFR expression predicts treatment failure in nasopharyngeal carcinoma

ObjectiveThis study inventively combines epidermal growth factor receptor (EGFR) expression of the primary lesion and standardized uptake value (SUV) of positron emission tomography and computed tomography (PET/CT) to predict the prognosis of nasopharyngeal carcinoma (NPC). This study aimed to evaluate the predictive efficacy of maximum standard uptake value (SUVmax) and EGFR for treatment failure in patients with NPC.MethodsThis retrospective study reviewed the results of EGFR expression and pretreatment 18F-FDG PET/CT of 313 patients with NPC. Time-dependent receiver operator characteristics was used for analyzing results and selecting the optimal cutoff values. Cox regression was used to screen out multiple risk factors. Cumulative survival rate was calculated by Kaplan–Meier.ResultsThe selected cutoff value of SUVmax-T was 8.5. The patients were categorized into four groups according to EGFR expression and SUVmax-T. There were significant differences in the 3-year local recurrence-free survival (LRFS) (p = 0.0083), locoregional relapse-free survival (LRRFS) (p = 0.0077), distant metastasis-free survival (DMFS) (p = 0.013), and progression-free survival (PFS) (p = 0.0018) among the four groups. Patients in the EGFR-positive and SUVmax-T > 8.5 group had the worst survival, while patients in the EGFR-negative and SUVmax-T ≤ 8.5 group had the best prognosis. Subsequently, patients with only positive EGFR expression or high SUVmax-T were classified as the middle-risk group. There were also a significant difference in 3-year overall survival among the three risk groups (p = 0.034). SUVmax-T was associated with regional recurrence-free survival and LRRFS in multivariate analysis, whereas EGFR was an independent prognostic factor for LRRFS, DMFS, and PFS.ConclusionThe combination of SUVmax-T and EGFR expression can refine prognosis and indicate clinical therapy.

Incidental gallbladder cancer and its contemporary management: From evaluation to targeted therapy

Gall bladder cancer (GBC) is the commonest malignancy of biliary tract. It is locally aggressive and potentially fatal in most of the patients. With the rise in the number of laparoscopic cholecystectomies being performed worldwide, incidental presentation of GBC is becoming common. The revelation of cancer for benign cholecystectomy presents a challenge. Incidental GBC needs detailed evaluation that includes review of preoperative imaging, histopathology report of cholecystectomy and high quality imaging to look for residual or metastatic disease. It is imperative to correctly stage the disease to formulate the best treatment strategy. For assessment of disease, triple-phase Contrast Enhanced Computed Tomography (CECT) scan and staging laparoscopy have definite roles; with Positron Emission Tomography and Computed Tomography (PET/CT) useful in confirming suspicious lesions. The factors associated with poor prognosis is presence of residual disease, lymphovascular invasion, grade of tumor and presence of metastatic lymph nodes. Neoadjuvant chemotherapy can be employed for the patients who are not candidate for upfront re-resection. Surgery includes liver excision and lymphadenectomy. Adjuvant therapy is indicated for higher stage tumor for improving survival, but response rate is low. Evaluation of biomarkers can provide a target for novel therapy.

MFCNet: A multi-modal fusion and calibration networks for 3D pancreas tumor segmentation on PET-CT images

In clinical diagnosis, positron emission tomography and computed tomography (PET-CT) images containing complementary information are fused. Tumor segmentation based on multi-modal PET-CT images is an important part of clinical diagnosis and treatment. However, the existing current PET-CT tumor segmentation methods mainly focus on positron emission tomography (PET) and computed tomography (CT) feature fusion, which weakens the specificity of the modality. In addition, the information interaction between different modal images is usually completed by simple addition or concatenation operations, but this has the disadvantage of introducing irrelevant information during the multi-modal semantic feature fusion, so effective features cannot be highlighted. To overcome this problem, this paper propose a novel Multi-modal Fusion and Calibration Networks (MFCNet) for tumor segmentation based on three-dimensional PET-CT images. First, a Multi-modal Fusion Down-sampling Block (MFDB) with a residual structure is developed. The proposed MFDB can fuse complementary features of multi-modal images while retaining the unique features of different modal images. Second, a Multi-modal Mutual Calibration Block (MMCB) based on the inception structure is designed. The MMCB can guide the network to focus on a tumor region by combining different branch decoding features using the attention mechanism and extracting multi-scale pathological features using a convolution kernel of different sizes. The proposed MFCNet is verified on both the public dataset (Head and Neck cancer) and the in-house dataset (pancreas cancer). The experimental results indicate that on the public and in-house datasets, the average Dice values of the proposed multi-modal segmentation network are 74.14% and 76.20%, while the average Hausdorff distances are 6.41 and 6.84, respectively. In addition, the experimental results show that the proposed MFCNet outperforms the state-of-the-art methods on the two datasets.

A Novel Lung Nodule Accurate Segmentation of PET-CT Images Based on Convolutional Neural Network and Graph Model

Positron Emission Tomography and Computed Tomography(PET/CT) imaging could obtain functional metabolic feature information and anatomical localization information of the patient body. However, tumor segmentation in PET/CT images is significantly challenging for fusing of dual-modality characteristic information. In this work, we have proposed a novel deep learning-based graph model network which can automatically fuse dual-modality information for tumor area segmentation. Our method rationally utilizes the advantage of each imaging modality(PET: the superior contrast, CT: the superior spatial resolution). We formulate this task as a Conditional Random Field(CRF) based on multi-scale fusion and dual-modality co-segmentation of object image with a normalization term which balances the segmentation divergence between PET and CT. This mechanism considers that the spatial varying characteristics acquire different scales, which encode various feature information over different modalities. The ability of our method was evaluated to detect and segment tumor regions with different fusion approaches using a dataset of PET/CT clinical tumor images. The results illustrated that our method effectively integrates both PET and CT modalities information, deriving segmentation accuracy result of 0.86 in DSC and the sensitivity of 0.83, which is 3.61% improvement compared to the W-Net.

68Ga-PSMA PET-CT and PSMA score affecting therapeutic decision-making in high-risk prostatic carcinoma.

This research study was conducted to evaluate the impact of (68Ga)-tagged prostatic-specific membrane antigen (68Ga-PSMA) positron emission tomography and computed tomography (PET-CT), compare its role with conventional radiology in early staging of high-risk prostate cancer, and calculate the PSMA score evaluating its usefulness in 68Ga-PSMA PET-CT reporting in our patient population. 68Ga-PSMA PET-CT of 65 high-risk cases of prostate cancer was performed for staging purpo-ses. Any change in disease stage was noted after 68Ga-PSMA PET-CT findings and PSMA score leading to a change in the management plan. Change in disease stage post-PSMA imaging was seen in 39% cases, high PSMA score (03) was noted in > 80% of upstaged cases, while low score (0) and (1) was seen in 65% and 35% down-staged individuals, respectively. Change in therapeutic decision-making was observed in 32% (21) of patients. 68Ga-PSMA PET-CT scans have a significant influence on the planned clinical management of high-risk prostate cancer patients; hence, they can be utilized as a replacement for radiological imaging tools, particularly in the detection of pelvic nodal and distant metastatic disease. PSMA score can be considered as an effective tool in standardized reporting of 68Ga-PSMA imaging.

Prevalence, Distribution, and Concomitance of Whole-Spine Ossification of the Posterior Longitudinal Ligament and Ossification of the Ligament Flavum in South Koreans: A Whole-Spine-CT-Based Cross-Sectional Study.

No studies assessing the prevalence of ossification of the spinal ligament were conducted using whole-spine positron emission tomography and computed tomography (PET-CT) in healthy Koreans. We aimed to determine the prevalence of ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligament flavum (OLF) in healthy Koreans using whole-body PET-CT. We reviewed whole-body PET-CT images captured during general health checkups at the General Health Promotion Center of our institution from January 2015 to 2020. OPLL and OLF were identified by the presence of heterotopic ossification in the posterior longitudinal ligament and ligament flavum on axial and sagittal PET-CT images. A total of 1,934 adults (1,645 men, 289 women) were included. The mean age was 48.05 years (range, 28-86 years). Among the 1,934 patients, 173 had OPLL (8.9%). The most commonly involved cervical vertebra levels arranged according to frequency were C4, C5, C3, and C6. OLF was observed in 125 patients (6.5%). The most commonly involved thoracic levels were T10, T11, and T5. The prevalence of OPLL and OLF was the highest in patients aged 60-69 years. Among the C-OPLL patients, 15.1% had T-OPLL, 5.0% had L-OPLL, and 25.8% had T-OLF. Our study revealed the prevalence of OPLL and OLF in healthy Korean subjects. It was consistent with that in other Asian countries. The presence of OPLL and OLF at most locations correlated with the presence or absence of spinal ossification at other locations.

Comparison of 18F-FDG and 68-PSMA-11 in PET for prostate cancer diagnosis

Prostate cancer is the second most incident neoplasm in men, except for non-melanoma skin cancer, and has the second highest mortality rate in Brazil. Early diagnosis increases the chances of cure and enables a less aggressive treatment for the patient. Nuclear Medicine presents effective alternatives for prostate cancer diagnosis, such as Positron Emission Tomography (PET) or PET and Computed Tomography (PET/CT) imaging. The aim of this study is to compare the advantages and disadvantages of the radiopharmaceuticals 18F-FDG and 68Ga-PSMA-11 used for PET or PET/CT in the diagnosis of this type of cancer. Compared to 18F-FDG, 68Ga-PSMA-11 has some advantages such as its availability by means of generators, the independent production of a cyclotron facility and its theranostic potential. The disadvantages compared to 18F-FDG are the scalability of 18F-FDG production compared to limited generator production. Despite its favorable characteristics, the radiopharmaceutical 18F-FDG has limitations in the diagnosis of some types of tumors, such as prostate cancer. All the favorable and unfavorable aspects of these two radiopharmaceuticals are presented in this work.