SPECT and PET serve as molecular imaging techniques and in vivo biomarkers for brain metastases

GD2-targeting therapy: a comparative analysis of approaches and promising directions

Disialoganglioside GD2 is a promising target for immunotherapy with expression primarily restricted to neuroectodermal and epithelial tumor cells. Although its role in the maintenance and repair of neural tissue is well-established, its functions during normal organism development remain understudied. Meanwhile, studies have shown that GD2 plays an important role in tumorigenesis. Its functions include proliferation, invasion, motility, and metastasis, and its high expression and ability to transform the tumor microenvironment may be associated with a malignant phenotype. Structurally, GD2 is a glycosphingolipid that is stably expressed on the surface of tumor cells, making it a suitable candidate for targeting by antibodies or chimeric antigen receptors. Based on mouse monoclonal antibodies, chimeric and humanized antibodies and their combinations with cytokines, toxins, drugs, radionuclides, nanoparticles as well as chimeric antigen receptor have been developed. Furthermore, vaccines and photoimmunotherapy are being used to treat GD2-positive tumors, and GD2 aptamers can be used for targeting. In the field of cell therapy, allogeneic immunocompetent cells are also being utilized to enhance GD2 therapy. Efforts are currently being made to optimize the chimeric antigen receptor by modifying its design or by transducing not only αβ T cells, but also γδ T cells, NK cells, NKT cells, and macrophages. In addition, immunotherapy can combine both diagnostic and therapeutic methods, allowing for early detection of disease and minimal residual disease. This review discusses each immunotherapy method and strategy, its advantages and disadvantages, and highlights future directions for GD2 therapy.

Fibroblast activation protein as a potential theranostic target in brain metastases of diverse solid tumours

Brain metastases are a very common and serious complication of oncological diseases. Despite the vast progress in multimodality treatment, brain metastases significantly decrease the quality of life and prognosis of patients. Therefore, identifying new targets in the microenvironment of brain metastases is desirable. Fibroblast activation protein (FAP) is a transmembrane serine protease typically expressed in tumour-associated stromal cells. Due to its characteristic presence in the tumour microenvironment, FAP represents an attractive theranostic target in oncology. However, there is little information on FAP expression in brain metastases. In this study, we quantified FAP expression in samples of brain metastases of various primary origin and characterised FAP-expressing cells. We have shown that FAP expression is significantly higher in brain metastases in comparison to non-tumorous brain tissues, both at the protein and enzymatic activity levels. FAP immunopositivity was localised in regions rich in collagen and containing blood vessels. We have further shown that FAP is predominantly confined to stromal cells expressing markers typical of cancer-associated fibroblasts (CAFs). We have also observed FAP immunopositivity on tumour cells in a portion of brain metastases, mainly originating from melanoma, lung, breast, and renal cancer, and sarcoma. There were no significant differences in the quantity of FAP protein, enzymatic activity, and FAP+ stromal cells among brain metastasis samples of various origins, suggesting that there is no association of FAP expression and/or presence of FAP+ stromal cells with the histological type of brain metastases. In summary, we are the first to establish the expression of FAP and characterise FAP-expressing cells in the microenvironment of brain metastases. The frequent upregulation of FAP and its presence on both stromal and tumour cells support the use of FAP as a promising theranostic target in brain metastases.

The role of [18F]fluorodopa positron emission tomography in grading of gliomas

PURPOSE

Gliomas are the most commonly occurring brain tumour in adults and there remains no cure for these tumours with treatment strategies being based on tumour grade. All treatment options aim to prolong survival, maintain quality of life and slow the inevitable progression from low-grade to high-grade. Despite imaging advancements, the only reliable method to grade a glioma is to perform a biopsy, and even this is fraught with errors associated with under grading. Positron emission tomography (PET) imaging with amino acid tracers such as [18F]fluorodopa (18F-FDOPA), [11C]methionine (11C-MET), [18F]fluoroethyltyrosine (18F-FET), and 18F-FDOPA are being increasingly used in the diagnosis and management of gliomas.

METHODS

In this review we discuss the literature available on the ability of 18F-FDOPA-PET to distinguish low- from high-grade in newly diagnosed gliomas.

RESULTS

In 2016 the Response Assessment in Neuro-Oncology (RANO) and European Association for Neuro-Oncology (EANO) published recommendations on the clinical use of PET imaging in gliomas. However, since these recommendations there have been a number of studies performed looking at whether 18F-FDOPA-PET can identify areas of high-grade transformation before the typical radiological features of transformation such as contrast enhancement are visible on standard magnetic resonance imaging (MRI).

CONCLUSION

Larger studies are needed to validate 18F-FDOPA-PET as a non-invasive marker of glioma grade and prediction of tumour molecular characteristics which could guide decisions surrounding surgical resection.

Neuroimaging with PET/CT in chronic traumatic encephalopathy: what nuclear medicine can do to move the field forward

INTRODUCTION

chronic traumatic encephalopathy (CTE) is a progressive neurodegenerative syndrome, caused by single or repeated traumatic brain injuries. Since a few years ago, post mortem examination represented the only effective method to diagnose CTE through the detection of its peculiar neuropathological features (i.e. tau protein aggregates) at a macroscopic and microscopic level. Several efforts have been made to develop radiopharmaceuticals characterized by high affinity for tau aggregates, suitable for imaging through Positron Emission Computed Tomography (Tau-PET).

AREAS COVERED

: The various radiopharmaceuticals utilized for the molecular imaging of CTE through Tau-PET are covered, with specific reference to their applications in clinical practice. Furthermore, PET probes binding to the translocator protein (TSPO), a marker of brain injury and repair, are reviewed as potential tools for the imaging of neuroinflammatory cascade associated with CTE.

EXPERT OPINION

molecular neuroimaging of CTE with Tau-PET is an intriguing, although still not completely explored, tool for the in vivo detection and monitoring of neuropathological hallmarks associated with CTE. Furthermore, some novel tracers, such as TSPO-ligands, hold the promise to get an insight into the complex physiopathological mechanisms leading from brain injury to symptomatic CTE.

Role of nanotechnology in animal production and veterinary medicine

Nanotechnology is the discipline and technology of small and specific things that are < 100 nm in size. Because of their extremely miniscule size, any changes in their chemical and physical structure may show higher reactivity and solubility than larger particles. Nanotechnology plays a vital role in every field of life. It is considered one of the most bleeding edge field of scientific research. It has already several applications in a myriad of disciplines while its application in the field of animal production and veterinary medicine is still experimental in nature. But, in recent years, the role of nanotechnology in the aforementioned fields of scientific inquiry has shown great progress. These days, nanotechnology has been employed to revolutionize drug delivery systems and diagnose atypical diseases. Applications of nanoparticle technology in the field of animal reproduction and development of efficacious vaccines have been at the forefront of scientific endeavors. Additionally, their impacts on meat and milk quality are also being judiciously inquired in recent decades. Veterinary nanotechnology has great potential to improve diagnosis and treatment, and provide new tools to this field. This review focuses on some noteworthy applications of nanoparticles in the field of animal production and their future perspectives.

18F-FDG-PET/CT analysis in hospitalized patients affected by pulmonary disease: The experience of the Nuclear Medicine Unit of "Policlinico Tor Vegata"

OBJECTIVE

The main aim of this study was to retrospectively evaluate the clinical data and outcomes of a cohort of 492 hospitalized patients who underwent fluorine-18-fluorodeoxyglucose (F-FDG)-PET/CT analysis at the nuclear medicine unit of 'Policlinico Tor Vergata' in Rome during the years 2017 and 2018 with particular emphasis for patients affected by pulmonary diseases.

METHODS

Anamnestic data (age and gender), main pathologic conditions, results of F-FDG-PET/CT examination, appropriateness of the request, and medical records of 492 consecutive hospitalized patients who underwent F-FDG-PET/CT analysis (55.38 ± 3.78 years; range 33-81 years) from January 2017 to December 2018 were obtained.

RESULTS

Considering all examinations, positive results were observed in 66.9% of cases whereas it was not possible to perform a diagnosis in 12.7% of cases (doubt results). About 20-fold increase in the percentage of doubt results was observed in F-FDG-PET/CT analysis with no appropriateness as compared to those with double appropriateness (both the request and clinical). Noteworthy, our data showed a 95% higher concordance between the positive results of the F-FDG-PET/CT examination and the histologic diagnosis. Conversely, the concordance between the analysis of the bronchoalveolar lavages and the PET analysis was very low.

CONCLUSION

Data here reported showed the high accuracy of the F-FDG-PET/CT performed in our department, mainly for pulmonary diseases, also highlighting the importance of continuously updating the selection criteria for patients who need PET examinations.

Construction of nanomaterials as contrast agents or probes for glioma imaging

Malignant glioma remains incurable largely due to the aggressive and infiltrative nature, as well as the existence of blood-brain-barrier (BBB). Precise diagnosis of glioma, which aims to accurately delineate the tumor boundary for guiding surgical resection and provide reliable feedback of the therapeutic outcomes, is the critical step for successful treatment. Numerous imaging modalities have been developed for the efficient diagnosis of tumors from structural or functional aspects. However, the presence of BBB largely hampers the entrance of contrast agents (Cas) or probes into the brain, rendering the imaging performance highly compromised. The development of nanomaterials provides promising strategies for constructing nano-sized Cas or probes for accurate imaging of glioma owing to the BBB crossing ability and other unique advantages of nanomaterials, such as high loading capacity and stimuli-responsive properties. In this review, the recent progress of nanomaterials applied in single modal imaging modality and multimodal imaging for a comprehensive diagnosis is thoroughly summarized. Finally, the prospects and challenges are offered with the hope for its better development.

SPECT imaging of cerebral blood flow changes induced by acute trigeminal nerve stimulation in drug-resistant epilepsy. A pilot study

OBJECTIVE

To explore the cortical areas targeted by acute transcutaneous trigeminal nerve stimulation (TNS) in patients with drug-resistant epilepsy (DRE) using single photon emission computed tomography (SPECT).

METHODS

Ten patients with DRE underwent brain SPECT at baseline and immediately after a 20-minute TNS (0.25 ms; 120 Hz; 30 s ON and 30 s OFF) applied bilaterally to the infraorbital nerve. The French Color Standard International Scale was used for qualitative analyses and z-scores were used to calculate the Odds Ratio (OR).

RESULTS

At baseline global hypoperfusion (mainly in temporo-mesial, temporo-parietal and fronto-temporal and temporo-occipital areas) was detected in all patients. Following TNS, a global increase in cortical tracer uptake and a significant decrease in median hypoperfusion score were observed. A significant effect favoring a general TNS-induced increase in cortical perfusion (OR = 4.96; p = 0.0005) was detected in 70% of cases, with significant effects in the limbic (p = 0.003) and temporal (p = 0.003) lobes. Quantitative analyses of z-scores confirmed significant TNS-induced increases in perfusion in the temporal (+0.59 SDs; p = 0.001), and limbic (+0.43 SDs; p = 0.03) lobes.

CONCLUSION

Short-term TNS is followed a global increase in cortical perfusion, namely in the temporal and limbic lobes.

SIGNIFICANCE

The TNS-induced perfusion increase may reflect neurons' activity changes in cortical areas implicated in the epilepsy network.

Two-versus three-dimensional regions of interest for quantifying SPECT-CT images

The aim of this study was to investigate the relationship of quantitative parameters between the two-dimensional region of interest (ROI) and the three-dimensional volume of interest (VOI) for accumulation of radiopharmaceutical. Single-photon emission computed tomography combined with computed tomography (SPECT/CT) images of the NEMA/IEC phantom were acquired. The ROIs and VOIs were automatically set to the sphere and background in the phantom. We defined as two-dimensional analysis (2D analysis) that which used ROIs set on the center section of the sphere, and as three-dimensional analysis (3D analysis) that which used VOIs set on the center of gravity of the sphere. Dose linearity (DL), the recovery coefficient (RC), the contrast-to-noise ratio (CNR), and standardized uptake value (SUV) were evaluated. Each index value was compared between both analyses. DL was almost 1 under both conditions. RC showed a similar tendency with 2D and 3D analyses. The CNR for 3D analysis was smaller than for 2D analysis. The maximum SUV was almost equal with both analyses. The mean SUV with 3D analysis was underestimated by 4.83% on average compared with 2D analysis. For the same accumulation, a difference may occur in the quantitative index between 2 and 3D analyses. In particular, the quantitative parameters based on the average value tends to be smaller with 3D analysis than 2D analysis. The quantitative parameters in 2D analysis showed dependence upon the cross section used for setting the ROI, whereas 3D analysis showed less dependence on the position of the VOI.

Inhibiting PI3K leads to glucose metabolism disturbance in default mode network

BACKGROUND

As the symbolic pathological changes of Alzheimer's disease (AD), hyperphosphorylated tau and amyloid plaque play important roles in the progression of the disease. In AD patients, the neural activity in default mode network is abnormal at different stages of the disease, and showed a hypoconnective status. Inhibition of phosphatidylinositol-3-kinase (PI3K) activates glycogen synthase kinase 3 beta (GSK-3β) and induces tau phosphorylation.

OBJECTIVE

We speculated that inhibiting cerebral PI3K altered the glucose metabolism in DMN. We aimed to explore the impacts of PI3K inhibition on tau phosphorylation, cerebral glucose metabolism, and synaptic plasticity.

METHODS

We injected wortmannin, an inhibitor of PI3K, lateral ventricularly in rats to mimic the pathology of AD. Immunohistochemistry was carried out to analyze the expression of phosphorylated tau. Region-specific glucose metabolism in the brain was analyzed using ¹⁸F-FDG PET imaging. In vivo long-term potentiation (LTP) in the hippocampus was detected to assess the synaptic plasticity.

RESULTS

The results show that the phosphorylated tau at T231 increased and the hippocampal LTP was suppressed 24 h after wortmannin administration. In the DMN, glucose uptake was significantly high, indicating a neural activity disturbance.

CONCLUSION

We conclude that targeting PI3K-GSK-3β pathway to mimic AD tau pathology interrupted the glucose metabolism of DMN brain regions.

Texture Analysis on [18F]FDG PET/CT in Non-Small-Cell Lung Cancer: Correlations Between PET Features, CT Features, and Histological Types

PURPOSE

The study aims to investigate the correlations between positron emission tomography (PET) texture features, X-ray computed tomography (CT) texture features, and histological subtypes in non-small-cell lung cancer evaluated with 2-deoxy-2-[¹⁸F]fluoro-D-glucose PET/CT.

PROCEDURES

We retrospectively evaluated the baseline PET/CT scans of 81 patients with histologically proven non-small-cell lung cancer. Feature extraction and statistical analysis were carried out on the Matlab platform (MathWorks, Natick, USA).

RESULTS

Intra-CT correlation analysis revealed a strong positive correlation between volume of the lesion (CT_vol) and maximum density (CT_max), and between kurtosis (CT_krt) and maximum density (CT_max). A moderate positive correlation was found between volume (CT_vol) and average density (CT_mean), and between kurtosis (CT_krt) and average density (CT_mean). Intra-PET analysis identified a strong positive correlation between the radiotracer uptake (SUV_max, SUV_mean) and its degree of variability/disorder throughout the lesion (SUV_std, SUV_ent). Conversely, there was a strong negative correlation between the uptake (SUV_max, SUV_mean) and its degree of uniformity (SUV_uni). There was a positive moderate correlation between the metabolic tumor volume (MTV) and radiotracer uptake (SUV_max, SUV_mean). Inter (PET-CT) correlation analysis identified a very strong positive correlation between the volume of the lesion at CT (CT_vol) and the metabolic volume (MTV), a moderate positive correlation between average tissue density (CT_mean) and radiotracer uptake (SUV_max, SUV_mean), and between kurtosis at CT (CT_krt) and metabolic tumor volume (MTV). Squamous cell carcinomas had larger volume higher uptake, stronger PET variability and lower uniformity than the other subtypes. By contrast, adenocarcinomas exhibited significantly lower uptake, lower variability and higher uniformity than the other subtypes.

CONCLUSIONS

Significant associations emerged between PET features, CT features, and histological type in NSCLC. Texture analysis on PET/CT shows potential to differentiate between histological types in patients with non-small-cell lung cancer.

Combining Diagnostic Imaging and Pathology for Improving Diagnosis and Prognosis of Cancer

In the era of personalized medicine, the management of oncological patients requires a translational and multidisciplinary approach. During early phases of cancer development, biochemical alterations of cell metabolism occur much before the formation of detectable tumour masses. Current molecular imaging techniques, targeted to the study of molecular kinetics, employ molecular tracers capable of detecting cancer lesions with both high sensitivity and specificity while also providing essential information for both prognosis and therapy. On the contrary, complementary and crucial information is provided by histopathological examination and ancillary techniques such as immunohistochemistry. Thus, the successful collaboration between diagnostic imaging and anatomic pathology can represent a fundamental step in the "tortuous" but decisive path towards personalized medicine.

Utility of Molecular Imaging with 2-Deoxy-2-[Fluorine-18] Fluoro-DGlucose Positron Emission Tomography (18F-FDG PET) for Small Cell Lung Cancer (SCLC): A Radiation Oncology Perspective

BACKGROUND AND OBJECTIVE

Although accounting for a relatively small proportion of all lung cancers, small cell lung cancer (SCLC) remains to be a global health concern with grim prognosis. Radiotherapy (RT) plays a central role in SCLC management either as a curative or palliative therapeutic strategy. There has been considerable progress in RT of SCLC, thanks to improved imaging techniques leading to accurate target localization for precise delivery of RT. Positron emission tomography (PET) is increasingly used in oncology practice as a non-invasive molecular imaging modality.

METHODS

Herein, we review the utility of molecular imaging with 2-deoxy-2-[fluorine-18] fluoro-Dglucose PET (18F-FDG PET) for SCLC from a radiation oncology perspective.

RESULTS

There has been extensive research on the utility of PET for SCLC in terms of improved staging, restaging, treatment designation, patient selection for curative/palliative intent, target localization, response assessment, detection of residual/recurrent disease, and prediction of treatment outcomes.

CONCLUSION

PET provides useful functional information as a non-invasive molecular imaging modality and may be exploited to improve the management of patients with SCLC. Incorporation of PET/CT in staging of patients with SCLC may aid in optimal treatment allocation for an improved therapeutic ratio. From a radiation oncology perspective, combination of functional and anatomical data provided by integrated PET/CT improves discrimination between atelectasis and tumor, and assists in the designation of RT portals with its high accuracy to detect intrathoracic tumor and nodal disease. Utility of molecular imaging for SCLC should be further investigated in prospective randomized trials to acquire a higher level of evidence for future potential applications of PET.

Prostate cancer and inflammation: A new molecular imaging challenge in the era of personalized medicine

The relationship between cancer and inflammation is one of the most important fields for both clinical and translational research. Despite numerous studies reported interesting and solid data about the prognostic value of the presence of inflammatory infiltrate in cancers, the biological role of inflammation in prostate cancer development is not yet fully clarified. The characterization of molecular pathways that connect altered inflammatory response and prostate cancer progression can provide the scientific rationale for the identification of new prognostic and predictive biomarkers. Specifically, the detection of infiltrating immune cells or related-cytokines by histology and/or by molecular imaging techniques could profoundly change the management of prostate cancer patients. In this context, the anatomic pathology and imaging diagnostic teamwork can provide a valuable support for the validation of new targets for diagnosis and therapy of prostate cancer lesions associated to the inflammatory infiltrate. The aim of this review is to summarize the current literature about the role of molecular imaging technique and anatomic pathology in the study of the mutual interaction occurring between prostate cancer and inflammation. Specifically, we reported the more recent advances in molecular imaging and histological methods for the early detection of prostate lesions associated to the inflammatory infiltrate.

Xiaoshuan enteric-coated capsule alleviates cognitive impairment by enhancing hippocampal glucose metabolism, hemodynamics and neuroplasticity of rat with chronic cerebral hypoperfusion

Chronic cerebral hypoperfusion (CCH) is identified as a critical risk factor of dementia in patients with cerebrovascular disease. Xiaoshuan enteric-coated capsule (XSECC) is a compound Chinese medicine approved by Chinese State Food and Drug Administration for promoting brain remodeling and plasticity after stroke. The present study aimed to explore the potential of XSECC to improve cognitive function after CCH and further investigate the underlying mechanisms. CCH was induced by bilateral common carotid artery occlusion (BCCAO) in rats. XSECC (420 or 140 mg/kg) treatment remarkably reversed BCCAO-induced cognitive deficits. Notably, after XSECC treatment, magnetic resonance angiography combined with arterial spin labeling noninvasively demonstrated significantly improved hippocampal hemodynamics, and ¹⁸F-FDG PET/CT showed enhanced hippocampal glucose metabolism. In addition, XSECC treatment markedly alleviated neuropathologies and improved neuroplasticity in the hippocampus. More importantly, XSECC treatment facilitated axonal remodeling by regulating the phosphorylation of axonal growth related proteins including protein kinase B (AKT), glycogen synthase kinase-3β (GSK-3β) and collapsin response mediator protein-2 (CRMP2) in the hippocampus. Taken together, the present study demonstrated the beneficial role of XSECC in alleviating BCCAO-induced cognitive deficits by enhancing hippocampal glucose metabolism, hemodynamics and neuroplasticity, suggesting that XSECC could be a useful strategy in cerebral hypoperfusion state and dementia.

Age- and Brain Region-Specific Changes of Glucose Metabolic Disorder, Learning, and Memory Dysfunction in Early Alzheimer's Disease Assessed in APP/PS1 Transgenic Mice Using 18F-FDG-PET

Alzheimer's disease (AD) is a leading cause of dementia worldwide, associated with cognitive deficits and brain glucose metabolic alteration. However, the associations of glucose metabolic changes with cognitive dysfunction are less detailed. Here, we examined the brains of APP/presenilin 1 (PS1) transgenic (Tg) mice aged 2, 3.5, 5 and 8 months using 18F-labed fluorodeoxyglucose (18F-FDG) microPET to assess age- and brain region-specific changes of glucose metabolism. FDG uptake was calculated as a relative standardized uptake value (SUVr). Morris water maze (MWM) was used to evaluate learning and memory dysfunction. We showed a glucose utilization increase in multiple brain regions of Tg mice at 2 and 3.5 months but not at 5 and 8 months. Comparisons of SUVrs within brains showed higher glucose utilization than controls in the entorhinal cortex, hippocampus, and frontal cortex of Tg mice at 2 and 3.5 months but in the thalamus and striatum at 3.5, 5 and 8 months. By comparing SUVrs in the entorhinal cortex and hippocampus, Tg mice were distinguished from controls at 2 and 3.5 months. In MWM, Tg mice aged 2 months shared a similar performance to the controls (prodromal-AD). By contrast, Tg mice failed training tests at 3.5 months but failed all MWM tests at 5 and 8 months, suggestive of partial or complete cognitive deficits (symptomatic-AD). Correlation analyses showed that hippocampal SUVrs were significantly correlated with MWM parameters in the symptomatic-AD stage. These data suggest that glucose metabolic disorder occurs before onset of AD signs in APP/PS1 mice with the entorhinal cortex and hippocampus affected first, and that regional FDG uptake increase can be an early biomarker for AD. Furthermore, hippocampal FDG uptake is a possible indicator for progression of Alzheimer's cognition after cognitive decline, at least in animals.

Evaluation of toxicity on epithelial and tumor cells of biaryl dipeptide tyrosines

We report a method to obtain biaryl dipeptide tyrosine via Suzuki-Miyaura and alkynyl dipeptide tyrosine by Sonogashira cross-coupling reactions. Analysis of the biological action of biaryl dipeptide tyrosine 4d compound showed its ability to impair the metabolism and proliferation of SK-Mel-28 human melanoma lineage cells, independently of mitochondrial membrane depolarization, apoptosis and necrosis. Moreover, 4d compound did not cause toxicity to human umbilical vein endothelial cells (HUVEC), suggesting its toxic specificity to cancer cells.

Insight into the Molecular Imaging of Alzheimer's Disease

Alzheimer's disease is a complex neurodegenerative disease affecting millions of individuals worldwide. Earlier it was diagnosed only via clinical assessments and confirmed by postmortem brain histopathology. The development of validated biomarkers for Alzheimer's disease has given impetus to improve diagnostics and accelerate the development of new therapies. Functional imaging like positron emission tomography (PET), single photon emission computed tomography (SPECT), functional magnetic resonance imaging (fMRI), and proton magnetic resonance spectroscopy provides a means of detecting and characterising the regional changes in brain blood flow, metabolism, and receptor binding sites that are associated with Alzheimer's disease. Multimodal neuroimaging techniques have indicated changes in brain structure and metabolic activity, and an array of neurochemical variations that are associated with neurodegenerative diseases. Radiotracer-based PET and SPECT potentially provide sensitive, accurate methods for the early detection of disease. This paper presents a review of neuroimaging modalities like PET, SPECT, and selected imaging biomarkers/tracers used for the early diagnosis of AD. Neuroimaging with such biomarkers and tracers could achieve a much higher diagnostic accuracy for AD and related disorders in the future.

Pancreatic tumors imaging: An update

Currently, ultrasound (US), computed tomography (CT) and Magnetic Resonance imaging (MRI) represent the mainstay in the evaluation of pancreatic solid and cystic tumors affecting pancreas in 80-85% and 10-15% of the cases respectively. Integration of US, CT or MR imaging is essential for an accurate assessment of pancreatic parenchyma, ducts and adjacent soft tissues in order to detect and to stage the tumor, to differentiate solid from cystic lesions and to establish an appropriate treatment. The purpose of this review is to provide an overview of pancreatic tumors and the role of imaging in their diagnosis and management. In order to a prompt and accurate diagnosis and appropriate management of pancreatic lesions, it is crucial for radiologists to know the key findings of the most frequent tumors of the pancreas and the current role of imaging modalities. A multimodality approach is often helpful. If multidetector-row CT (MDCT) is the preferred initial imaging modality in patients with clinical suspicion for pancreatic cancer, multiparametric MRI provides essential information for the detection and characterization of a wide variety of pancreatic lesions and can be used as a problem-solving tool at diagnosis and during follow-up.