Nuclear imaging for functional evaluation and theragnosis in liver malignancy and transplantation

Currently, nuclear imaging such as positron emission tomography (PET) and single photon emission computed tomography (SPECT) is increasingly used in the management of liver malignancy. 18F-fluorodeoxyglucose (FDG)-PET is the most widely used nuclear imaging in liver malignancy as in other cancers, and has been reported to be effective in diagnosis, response monitoring, recurrence evaluation, and prognosis prediction. Other PET imaging such as 11C-acetate PET is also used complementarily to FDG-PET in diagnosis of liver malignancy. Additionally, image-based evaluation of regional hepatic function can be performed using nuclear imaging. Those imaging modalities are also effective for candidate selection, treatment planning, and perioperative evaluation in liver surgery and transplantation. Recently, nuclear imaging has been actively adopted in the transarterial radioembolization therapy of liver malignancy, according to the concept of theragnosis. With the development of new hybrid imaging technologies such as PET/magnetic resonance imaging and SPECT/CT, nuclear imaging is expected to be more useful in the management of liver malignancy, particularly regarding liver surgery and transplantation. In this review, the efficacy and roles of nuclear imaging methods in diagnosis, transplantation and theragnosis are discussed.

Structural control of magnetic nanoparticles for positive nuclear magnetic resonance imaging

In addition to the tens of millions of medical doses consumed annually around the world,a vast number of nuclear magnetic resonance imaging(MRI)contrast agents are being deployed in MRI research and development,offering precise diagnostic information,targeting capabilities,and analyte sensing.Superparamagnetic iron oxide nanoparticles(SPIONs)are notable among these agents,providing effective and versatile MRI applications while also being heavy-metal-free,bioconjugatable,and theranostic.We designed and implemented a novel two-pronged computational and experimental strategy to meet the demand for the efficient and rigorous development of SPION-based MRI agents.Our MATLAB-based modeling simulation and magnetic characterization revealed that extremely small maghemite SPIONs in the 1-3 nm range possess significantly reduced transversal relaxation rates(R_(2))and are therefore preferred for positive(T_(1)-weighted)MRI.Moreover,X-ray diffraction and X-ray absorption fine structure analyses demonstrated that the diffraction pattern and radial distribution function of our SPIONs matched those of the targeted maghemite crystals.In addition,simulations of the X-ray near-edge structure spectra indicated that our synthesized SPIONs,even at 1 nm,maintained a spherical structure.Furthermore,in vitro and in vivo MRI investigations showed that our 1-nm SPIONs effectively highlighted whole-body blood vessels and major organs in mice and could be cleared through the kidney route to minimize potential post-imaging side effects.Overall,our innovative approach enabled a swift discovery of the desired SPION structure,followed by targeted synthesis,synchrotron radiation spectroscopic studies,and MRI evaluations.The efficient and rigorous development of our high-performance SPIONs can set the stage for a computational and experimental platform for the development of future MRI agents.

Multi-modality parathyroid imaging:A shifting paradigm

The goal of parathyroid imaging in hyperparathyroidism is not diagnosis,rather it is the localization of the cause of hyperparathyroidism for planning the best therapeutic approach.Hence,the role of imaging to accurately and precisely localize the abnormal parathyroid tissue is more important than ever to facilitate minimally invasive parathyroidectomy over bilateral neck exploration.The common causes include solitary parathyroid adenoma,multiple parathyroid adenomas,parathyroid hyperplasia and parathyroid carcinoma.It is highly imperative for the radiologist to be cautious of the mimics of parathyroid lesions like thyroid nodules and lymph nodes and be able to differentiate them on imaging.The various imaging modalities available include high resolution ultrasound of the neck,nuclear imaging studies,four-dimensional computed tomography(4D CT)and magnetic resonance imaging.Contrast enhanced ultrasound is a novel technique which has been recently added to the armam-entarium to differentiate between parathyroid adenomas and its mimics.Through this review article we wish to review the imaging features of parathyroid lesions on various imaging modalities and present an algorithm to guide their radiological differentiation from mimics.

Role of functional imaging in the development and refinement of invasive neuromodulation for psychiatric disorders

Deep brain stimulation(DBS) is emerging as a pow-erful tool for the alleviation of targeted symptoms in treatment-resistant neuropsychiatric disorders. Despite the expanding use of neuropsychiatric DBS, the mecha-nisms responsible for its effects are only starting to be elucidated. Several modalities such as quantitative elec-troencephalography as well a intraoperative recordings have been utilized to attempt to understand the under-pinnings of this new treatment modality, but functional imaging appears to offer several unique advantages. Functional imaging techniques like positron emission tomography, single photon emission computed tomog-raphy and functional magnetic resonance imaging have been used to examine the effects of focal DBS on activ-ity in a distributed neural network. These investigations are critical for advancing the field of invasive neuro-modulation in a safe and effective manner, particularly in terms of defining the neuroanatomical targets and refining the stimulation protocols. The purpose of this review is to summarize the current functional neuroim-aging findings from neuropsychiatric DBS implantation for three disorders: treatment-resistant depression, obsessive-compulsive disorder, and Tourette syndrome. All of the major targets will be discussed(Nucleus ac-cumbens, anterior limb of internal capsule, subcallosal cingulate, Subthalamic nucleus, Centromedial nucleus of the thalamus-Parafasicular complex, frontal pole, and dorsolateral prefrontal cortex). We will also address some apparent inconsistencies within this literature, and suggest potential future directions for this promis-ing area.

Tc-99m ciprofloxacin imaging in acute cholecystitis

AIM: To evaluate the eff icacy of a new nuclear imaging Infecton (Tc-99m ciprofloxacin) for the diagnosis of acute cholecystitis. METHODS: Sixteen patients thought to have acute cholecystitis were included in this study. The diagnosis of acute cholecystitis was made based on clinical symptoms and ultrasonographic and pathologic f indings. RESULTS: The 16 patients were composed of 12 acute and 4 chronic cholecystitis patients. Twelve patients with acute cholecystitis were image-positive, including one false-positive. Four patients with chronic cholecystitis were image-negative, of whom three were true-negative. This nuclear imaging had a sensitivity of 91.7%, a specificity of 75%, a positive-predictive value of 91.7%, and a negative-predictive value of 75%. CONCLUSION: Tc-99m ciprofloxacin imaging is easy to perform and applicable for the diagnosis of acute cholecystitis.

Multi-modality imaging of cardiac amyloidosis: Contemporary update

Cardiac amyloidosis is a heterogeneous and challenging diagnostic disease with poor prognosis that is now being altered by introduction of new therapies.Echocardiography remains the first-line imaging tool, and when disease is suspected on echocardiography, cardiac magnetic resonance imaging and nuclear imaging play critical roles in the non-invasive diagnosis and evaluation of cardiac amyloidosis. Advances in multi-modality cardiac imaging allowing earlier diagnosis and initiation of novel therapies have significantly improved the outcomes in these patients. Cardiac imaging also plays important roles in the risk stratification of patients presenting with cardiac amyloidosis. In the current review, we provide a clinical and imaging focused update, and importantly outline the imaging protocols, diagnostic and prognostic utility of multimodality cardiac imaging in the assessment of cardiac amyloidosis.

Diagnostic and prognostic value of cardiac imaging in amyloidosis

Amyloidosis is an infiltrative disease caused by extracellular protein deposition that has accumulated a lot of scientific production in recent years.Different types of amyloidosis can affect the heart.Transthyretin amyloidosis and light chain amyloidosis are the two most common types of cardiac amyloidosis.These entities have a poor prognosis,so accurate diagnostic techniques are imperative for determining an early therapeutic approach.Recent advances in cardiac imaging and diagnostic strategies show that these tools are safe and can avoid the use of invasive diagnostic techniques to histological confirmation,such as endomyocardial biopsy.We performed a review on the diagnostic and prognostic implications of different cardiac imaging techniques in cardiac amyloidosis.We mainly focus on reviewing echocardiography,cardiac magnetic resonance,computed tomography and nuclear imaging techniques and the different safety measurements that can be done with each of them.

SAR image de-noising based on texture strength and weighted nuclear norm minimization

As synthetic aperture radar（SAR） has been widely used nearly in every field, SAR image de-noising became a very important research field. A new SAR image de-noising method based on texture strength and weighted nuclear norm minimization（WNNM） is proposed. To implement blind de-noising, the accurate estimation of noise variance is very important. So far, it is still a challenge to estimate SAR image noise level accurately because of the rich texture. Principal component analysis（PCA） and the low rank patches selected by image texture strength are used to estimate the noise level. With the help of noise level, WNNM can be expected to SAR image de-noising. Experimental results show that the proposed method outperforms many excellent de-noising algorithms such as Bayes least squares-Gaussian scale mixtures（BLS-GSM） method, non-local means（NLM） filtering in terms of both quantitative measure and visual perception quality.

In-situ observation and modeling approach to evolution of pore-fracture structure in coal

The characterisation of the pore-fracture structure(PFS)and its evolution in coal during mining are essential for preventing gas outbursts and improving gas extraction efficiency.In this study,the evolution of the PFS in coal samples under the condition of mining stress was directly captured in situ by combination of the mechanical testing system with high-precision visualisation nuclear magnetic resonance equipment.A fractional derivative model was established to describe the relationship between stress and porosity based on experimental results of the PFS under different stress states.The results showed that with an increase in the deviatoric stress,the adsorption pore content increases rapidly initially and then increases slowly or remains unchanged;the seepage pore and fracture(SPF)content decreases initially and then increases.The SPF compressibility coefficient decreases with an increase in the deviatoric stress.The fractional derivative model can accurately describe the stress sensitivity of the SPFs at the pre-peak stage,thus providing a new approach for accurately characterising the seepage characteristics of coal reservoirs.

Multimodality image fusion for diagnosing coronary artery disease

Coronary artery disease （CAD） is one of the leading causes of death in the US and a substantial health-care burden in all industrialized societies. In recent years we have witnessed a constant strive towards the development and the clinical application of novel or improved detection methods as well as therapies. Particularly, noninvasive imaging is a decisive component in the cardiovascular field. Image fusion is the ability of combining into a sin- gle integrated display the anatomical as well as the physiological data retrieved by separated modalities. Clinical evidence suggests that it represents a promising strategy in CAD assessment and risk stratification by significantly improving the diagnostic power of each modality independently considered and of the traditional side-by-side in- terpretation. Numerous techniques and approaches taken from the image registration field have been implemented and validated in the context of CAD assessment and management. Although its diagnostic power is widely ac- cepted, additional technical developments are still needed to become a routinely used clinical tool.

Imbibition characteristics of sandstone cores with different permeabilities in nanofluids

The core imbibition and shifting nuclear magnetic resonance(NMR) imaging experiment has loss of surface oil phase and air adsorption, which will affect the accuracy of the experiment result. To solve this issue, a modified experiment method, in-situ imbibition NMR method has been worked out. This method was used to carry out sandstone core imbibition experiment in nanofluid, and the oil migration images in the entire process were recorded. In combination with physical properties of the sandstone cores and the variations of the driving force during the imbibition process, imbibition characteristics of the sandstone cores with different permeabilities in nanofluid were analyzed. The results show that: the nanofluid can greatly reduce the interfacial tension of oil phase and improve the efficiency of imbibition and oil discharge, the higher the concentration, the lower the interfacial tension and the higher the efficiency of imbibition and oil discharge would be, but when the concentration reaches a certain value, the increase in imbibition and oil discharge efficiency slows down;the rise of temperature can reduce the oil viscosity resistance and interfacial tension, and hence enhance the imbibition and oil discharge rate;when the sandstone core is higher in permeability, the bottom crude oil would migrate upward and discharge during the imbibition, the higher the permeability of the sandstone core, the more obvious this phenomenon would be, and the phenomenon is shown as top oil discharge characteristic;when the sandstone core is low in permeability, the crude oil in the outer layer of the sandstone core would discharge first during the imbibition, then crude oil in the inside of the core would disperse outside and discharge, which is shown as oil discharge characteristic around the core;but under long time effect of nanofluid, the core would become more and more water-wet and reduce in the oil-water interfacial tension, so would have top oil discharge characteristic in the later stage of imbibition.

Study of MR image for involvement of paranasal sinuses in 56 cases with nasopharyngeal carcinoma

Objective： The aim of the study was to study the nuclear magnetic resonance image （MRI） feature for involvement of paranasal sinuses in patients with nasopharyngeal carcinoma （NPC）. Methods： The MRI of 56 patients with NPC and paranasal sinuses infringed were evaluated between December 2003 and August 2004. Results： Among them, 56 （100%） showed breakage in the wall of paranasal sinuses, 29 （51.8%） had thick mucous membrane in sinuses, 36 （64.3%） showed tumour invasion sinuses, 55 （98.2%） connected with primary carcinoma with the lesion, and 14 （25%） stored up fluid in si- nuses. On MRI scan technique, the positive ratios of diagnoses were 66.1%, 76.8%, and 98.2% respectively （P 〈 0.000） in the horizontal section, coronal section and sagittal section. And nearly 60% was in the TlWl and T2Wl, but 100% in strengthen scan. Conclusion： The findings of sinuses wall breakage, thick mucous membrane in sinuses, tumour invasion cavity connective mass, and same enhancement signal in MR image may indicate the paranasal sinuses involved by primary turnout. The sagittal section and enhanced MRI scans are helpful to diagnosis.

^(188)Re-LABELED HYPERBRANCHED POLYSULFONAMINE AS A ROBUST TOOL FOR TARGETED CANCER DIAGNOSIS AND RADIOIMMUNOTHERAPY

Hyperbranched polysulfonamine （HPSA） is a promising biomaterial due to its highly branched spherical architecture and efficient intracellular translocation. To realize the fianctionalization of HPSA, both N-succinimidyl 3-（2- pyridyldithio） propionate （SPDP） for tethering the human-mouse chimeric monoclonal antibody CH12 and N-hydroxy succinimidyl S-acetylmercaptoacetyltriglycinate （NHS-MAG3） for labeling 188Re were sequentially grafted onto the primary amine terminals of HPSA via covalent linkages, attaining the SPDP-HPSA-MAG3 intermediate. In order to reserve the structural integrity of CH12, the fragment crystallizable （Fc） region was also processed by oxidation of oligosaccharide moieties with sodium periodate and then reacted with N-（κ-maleimidoundecanoic acid） hydrazide （KMUH）. After chelating 188Re with MAG3 group, the SPDP was reduced to PDP and connected onto the maleinimide group at the Fc region. As a result, both the epidermal growth factor receptor viii （EGFRvIII） targeted monoclonal antibody CH12 and the radionuclide 188Re were conjugated to the HPSA-based vehicles, forming the 188Re-labeled and CH12-tethered HPSA （CH12-HPSA- 188Re）. The molecular weight and in vitro stability of CH12-HPSA-188Re were evaluated by gel electrophoresis and paper chromatography. On one hand, the CH12-HPSA-188Re could specifically bind to the EGFRvlII-positive human hepatocarcinoma cells in vitro. On the other hand, it could also target at the tumor tissue of nude mice in vivo. Hence, the CH12-HPSA-188Re could effectively target at the human hepatocarcinoma and facilitate the tumor detection and targeted radioimmunotherapy.

The potential clinical applications of radionuclide labeled/doped gold-based nanomaterials

Radionuclides have been widely used for multimodal imaging and radioisotope therapy of cancer.Various nanomaterials have been developed as excellent nanocarriers of radionuclides for the targeted delivery into tumors,in order to minimize the unnecessary side effect and enhance the therapeutic efficacy of radiotherapy.Among those nanomaterials,gold nanomaterials with tunable morphologies,easy modification,good biological safety,and radiation sensitization capability are excellent candidates for cancer theranostics.Given the superior performance of gold-based nanomaterials in biomedicine,we summary the recent advance of radionuclide labeled/doped gold-based nanomaterials for cancer theranostics.In this review article,we will discuss the methods for labelling or doping radionuclides onto gold nanomaterials,their applications for nuclear imaging and Cerenkov luminescence(CL)imaging,as well as the radioisotope therapy of cancer,and finally the toxicity evaluation of radionuclide labeled/doped gold-based nanomaterials.We hope that our review article would provide guidance for non-experts to design the radiolabeled nanomaterials for cancer imaging guided therapy.