Secondary rectal linitis plastica caused by prostatic adenocarcinoma-magnetic resonance imaging findings and dissemination pathways:A case report

BACKGROUND Secondary rectal linitis plastica(RLP)from prostatic adenocarcinoma is a rare and poorly understood form of metastatic spread,characterized by a desmoplastic response and concentric rectal wall infiltration with mucosal preservation.This complicates endoscopic diagnosis and can mimic gastrointestinal malignancies.This case series underscores the critical role of magnetic resonance imaging(MRI)in identifying the distinct imaging features of RLP and highlights the importance of considering this condition in the differential diagnosis of patients with a history of prostate cancer.CASE SUMMARY Three patients with secondary RLP due to prostatic adenocarcinoma presented with varied clinical features.The first patient,a 76-year-old man with advanced prostate cancer,had rectal pain and incontinence.MRI showed diffuse prostatic invasion and significant rectal wall thickening with a characteristic"target sign"pattern.The second,a 57-year-old asymptomatic man with elevated prostatespecific antigen levels and a history of prostate cancer exhibited rectoprostatic angle involvement and rectal wall thickening on MRI,with positron emission tomography/computed tomography PSMA confirming the prostatic origin of the metastatic spread.The third patient,an 80-year-old post-radical prostatectomy,presented with refractory constipation.MRI revealed a neoplastic mass infiltrating the rectal wall.In all cases,MRI consistently showed stratified thickening,concentric signal changes,restricted diffusion,and contrast enhancement,which were essential for diagnosing secondary RLP.Biopsies confirmed the prostatic origin of the neoplastic involvement in the rectum.CONCLUSION Recognizing MRI findings of secondary RLP is essential for accurate diagnosis and management in prostate cancer patients.

Investigating the relationship between intracranial atherosclerotic plaque remodelling and diabetes using high-resolution vessel wall imaging

BACKGROUND Intracranial atherosclerosis,a leading cause of stroke,involves arterial plaque formation.This study explores the link between plaque remodelling patterns and diabetes using high-resolution vessel wall imaging(HR-VWI).AIM To investigate the factors of intracranial atherosclerotic remodelling patterns and the relationship between intracranial atherosclerotic remodelling and diabetes mellitus using HR-VWI.METHODS Ninety-four patients diagnosed with middle cerebral artery or basilar artery INTRODUCTION Intracranial atherosclerotic disease is one of the main causes of ischaemic stroke in the world,accounting for approx-imately 10%of transient ischaemic attacks and 30%-50%of ischaemic strokes[1].It is the most common factor among Asian people[2].The adaptive changes in the structure and function of blood vessels that can adapt to changes in the internal and external environment are called vascular remodelling,which is a common and important pathological mechanism in atherosclerotic diseases,and the remodelling mode of atherosclerotic plaques is closely related to the occurrence of stroke.Positive remodelling(PR)is an outwards compensatory remodelling where the arterial wall grows outwards in an attempt to maintain a constant lumen diameter.For a long time,it was believed that the degree of stenosis can accurately reflect the risk of ischaemic stroke[3-5].Previous studies have revealed that lesions without significant luminal stenosis can also lead to acute events[6,7],as summarized in a recent meta-analysis study in which approximately 50%of acute/subacute ischaemic events were due to this type of lesion[6].Research[8,9]has pointed out that the PR of plaques is more dangerous and more likely to cause acute ischaemic stroke.Previous studies[10-13]have found that there are specific vascular remodelling phenomena in the coronary and carotid arteries of diabetic patients.However,due to the deep location and small lumen of intracranial arteries and limitations of imaging techniques,the relationship between intracranial arterial remodelling and diabetes is still unclear.In recent years,with the development of magnetic resonance technology and the emergence of high-resolution(HR)vascular wall imaging,a clear and multidimensional display of the intracranial vascular wall has been achieved.Therefore,in this study,HR wall imaging(HR-VWI)was used to display the remodelling characteristics of bilateral middle cerebral arteries and basilar arteries and to explore the factors of intracranial vascular remodelling and its relationship with diabetes.

Combination of three-gene immunohistochemical panel and magnetic resonance imaging-detected extramural vascular invasion to assess prognosis in non-advanced rectal cancer patients

AIM To identify a small, clinically applicable immunohistochemistry(IHC) panel that could be combined with magnetic resonance imaging(MRI)-detected extramural vascular invasion(EMVI) for assessment of prognosis concerning the non-advanced rectal cancer patients prior to operation.METHODS About 329 patients with pathologically confirmed rectal carcinoma(RC) were screened in this research, all of whom had been examined via an MRI and were treatment-na?ve from July 2011 to July 2014. The candidate proteins that were reported to be altered by RC were examined in tissues by IHC. All chosen samples were adopted from the fundamental cores of histopathologically confirmed carcinomas during the initial surgeries.RESULTS Of the three proteins that were tested, c-MYC, PCNA and TIMP1 were detected with relatively significant expression in tumors, 35.9%, 23.7% and 58.7% respectively. The expression of the three proteins were closely connected with prognosis(P = 0.032, 0.003, 0.021). The patients could be classified into different outcome groups according to an IHC panel(P < 0.01) via these three proteins. Taking into consideration known survival covariates, especially EMVI, the IHC panel served as an independent prognostic factor. The EMVI combined with the IHC panel could categorize patients into different prognostic groups with distinction(P < 0.01).CONCLUSION These studies argue that this three-protein panel of c-MYC, PCNA, coupled with TIMP1 combined with MRIdetected EMVI could offer extra prognostic details for preoperative treatment of RC.

Long term evolution of magnetic resonance imaging characteristics in a case of atypical left lateral wall hypertrophic cardiomyopathy

We are reporting a long-time magnetic resonance imaging(MRI) follow-up in a rare case of cardiac left lateral wall hypertrophy. Hypertrophic cardiomyopathy(HCM) is the most common genetic cardiovascular disorder and a significant cause of sudden cardiac death. Cardiac magnetic resonance(CMR) imaging can be a valuable tool for assessment of detailed information on size,localization,and tissue characteristics of hypertrophied myocardium. However,there is still little knowledge of long-term evolution of HCM as visualized by magnetic resonance imaging. Recently,our group reported a case of left lateral wall HCM as a rare variant of the more common forms,such as septal HCM,or apical HCM. As we now retrieved an old cardiac MRI acquired in this patient more than 20 years ago,we are able to provide the thrilling experience of an ultra-long MRI followup presentation in this rare case of left lateral wall hypertrophy. Furthermore,this case outlines the tremendous improvements in imaging quality within the last two decades of CMR imaging.

Advances in multimodal magnetic resonance imaging of vascular mild cognitive impairment

Vascular mild cognitive impairment(VaMCI)represents the early stage of symptoms of vascular cognitive impairment(VCI).There are many intervention factors in this period.If the active treatment can delay the further development of the disease and even reduce the risk of transforming into vascular dementia(VaD).As a widely used imaging method,multi-mode magnetic resonance imaging can evaluate the brain structure and function of patients with VaMCI noninvasively and explore the relationship between brain structure,function and cognitive function change.It is beneficial to provide an idea for early diagnosis of VaMCI and to further understand the neuropathologic mechanism of its occurrence,which has broad application prospects.In this paper,the research status and new methods of VaMCI are reviewed by using multi-mode magnetic resonance imaging in recent years.

Imaging plaque inflammation in asymptomatic cocaine addicted individuals with simultaneous positron emission tomography/magnetic resonance imaging

BACKGROUND Chronic cocaine use is associated with stroke, coronary artery disease and myocardial infarction, resulting in severe impairments or sudden mortality. In the absence of clear cardiovascular symptoms, individuals with cocaine use disorder (iCUD) seeking addiction treatment receive mostly psychotherapy and psychiatric pharmacotherapy, with no attention to vascular disease (i.e., atherosclerosis). Little is known about the pre-clinical signs of cardiovascular risk in iCUD and early signs of vascular disease are undetected in this underserved population. AIM To assess inflammation, plaque burden and plaque composition in iCUD aiming to detect markers of atherosclerosis and vascular disease. METHODS The bilateral carotid arteries were imaged with positron emission tomography/magnetic resonance imaging (PET/MRI) in iCUD asymptomatic for cardiovascular disease, healthy controls, and individuals with cardiovascular risk. PET with 18F-fluorodeoxyglucose (18F-FDG) evaluated vascular inflammation and 3-D dark-blood MRI assessed plaque burden including wall area and thickness. Drug use and severity of addiction were assessed with standardized instruments. RESULTS The majority of iCUD and controls had carotid FDG-PET signal greater than 1.6 but lower than 3, indicating the presence of mild to moderate inflammation. However, the MRI measure of wall structure was thicker in iCUD as compared to the controls and cardiovascular risk group, indicating greater carotid plaque burden. iCUD had larger wall area as compared to the healthy controls but not as compared to the cardiovascular risk group, indicating structural wall similarities between the non-control study groups. In iCUD, wall area correlated with greater cocaine withdrawal and craving. CONCLUSION These preliminary results show markers of carotid artery disease burden in cardiovascular disease-asymptomatic iCUD. Broader trials are warranted to develop protocols for early detection of cardiovascular risk and preventive intervention in iCUD.

Magnetic Resonance Imaging of Coronary Arteries:Latest Technical Innovations and Clinical Experiences

Cardiovascular disease(CVD)is the leading cause of death and a major health care challenge globally.Coronary artery disease(CAD)is a primary underlying pathological process in the majority of cardiovascular disease cases.Magnetic resonance imaging(MRI)can play a potentially important role in the management of CAD as a noninvasive imaging modality without ionizing radiation,although its early promise has not been delivered because of several crucial technical limitations.However,recent innovations in MRI have reopened the door,with tremendous opportunities for multiparametric assessment of CAD including luminal stenosis,plaque burden and composition,and disease activities such as infl ammation and hemorrhage.Novel MRI acquisition and reconstruction strategies now offer much increased spatial resolution and image quality and shortened examination times compared with conventional approaches.Recent clinical experiences of coronary MRI indicated the potential to improve the current management of coronary atherosclerosis,such as identifying the patients at the highest risk and evaluating therapeutic responses.In this review we discuss the latest technical advances and clinical insights in coronary MRI.

Evaluation of tumor response to antiangiogenic therapy in patients with recurrent gliomas using contrast-enhanced perfusion-weighted magnetic resonance imaging techniques:A meta-analysis

BACKGROUND It is of vital importance to find radiologic biomarkers that can accurately predict treatment response. Usually, the initiation of antiangiogenic therapy causes a rapid decrease in the contrast enhancing tumor. However, the treatment response is observed only in a fraction of patients due to the partial radiological response secondary to stabilization of abnormal vessels which does not essentially indicate a true antitumor effect. Perfusion-weighted magnetic resonance imaging(PWMRI) techniques have shown implicitness as a strong imaging biomarker for gliomas since they give hemodynamic information of blood vessels. Hence, there is a rapid expansion of PW-MRI related studies and clinical applications.AIM To determine the diagnostic performance of PW-MRI techniques including:(A)dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI); and(B)dynamic susceptibility contrast magnetic resonance imaging(DSC-MRI) for evaluating response to antiangiogenic therapy in patients with recurrent gliomas.METHODS Databases such as PubMed(MEDLINE included), EMBASE, and Google Scholar were searched for relevant original articles. The included studies were assessed for methodological quality with the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Medical imaging follow-up or histopathological analysis was used as the reference standard. The data were extracted by two reviewers independently, and then the sensitivity, specificity, summary receiver operating characteristic curve, area under the curve(AUC), and heterogeneity were calculated using Meta-Disc 1.4 software.RESULTS This study analyzed a total of six articles. The overall sensitivity for DCE-MRI and DSC-MRI was 0.69 [95% confidence interval(CI): 0.53-0.82], and the specificity was 0.99(95%CI: 0.93-1) by a random effects model(DerSimonianeeLaird model). The likelihood ratio(LR) +, LR-, and diagnostic odds ratio(DOR)were 12.84(4.54-36.28), 0.35(0.22-0.53), and 24.44(7.19-83.06), respectively. The AUC(± SE) was 0.9921(± 0.0120), and the Q* index(± SE) was 0.9640(± 0.0323).For DSC-MRI, the sensitivity was 0.73, the specificity was 0.98, the LR+ was 7.82,the LR-was 0.32, the DOR was 31.65, the AUC(± SE) was 0.9925(± 0.0132), and the Q* index was 0.9649(± 0.0363). For DCE-MRI, the sensitivity was 0.41, the specificity was 0.97, the LR+ was 5.34, the LR-was 0.71, the DOR was 8.76, the AUC(± SE) was 0.9922(± 0.2218), and the Q* index was 0.8935(± 0.3037).CONCLUSION This meta-analysis demonstrated a beneficial value of PW-MRI(DSC-MRI and DCE-MRI) in monitoring the response of recurrent gliomas to antiangiogenic therapy, with reasonable sensitivity, specificity, +LR, and-LR.

Dynamic contrast-enhanced magnetic resonance perfusion weighted imaging in astrocytomas: correlation with histopathology and immunohistochemistry

Objective:To investigate magnetic resonance perfusion weighted imaging and its relationship with the grading and the expression of vascular endothelial growth factor (VEGF) and angiogenesis in astrocytomas. Methods: A collection of 34 patients with astrocytomas proved by surgery and pathology were examined by magnetic resonance imaging(MRI), with 26 cases of gradeⅠ-Ⅱ(low-grade) and 8 cases of grade Ⅲ-Ⅳ(high-grade). MR perfusion images were obtained with spin-echo echo planar imaging (SE-EPI) techniques. Expression of VEGF was examined by immunohistochemical method of streptavidin-biotin-peroxidase(SP). The vascular development was measured by micro-vascular density (MVD) which was immunostained with anti-factor Ⅷ-related antigen monoclonal antibody. Results: Both of the expression of VEGF and the angiogenesis in 34 cases of astrocytomas were significantly correlated to the maximum relative cerebral blood volume (Max rCBV) (r=0.604, P<0.001;r=0.625, P<0.001, respectively). The Max rCBV and the expression of VEGF, MVD in high-grade astrocytomas were significantly higher than that of in low-grade astrocytomas (t= 3.0, P=0.017; t=7.08, P=0.01;t=3.37,P=(0.011,) respectively). Conclusion: MR perfusion weighted imaging might be a valuable method in in vivo study of the angiogenesis of astrocytomas and evaluating their malignant degree and prognosis.

Non-invasive assessment of intracranial wall shear stress using high-resolution magnetic resonance imaging in combination with computational fluid dynamics technique

In vivo studies on association between wall shear stress(WSS)and intracranial plaque are deficient.Based on the three-dimensional T1-weighted high-resolution magnetic resonance imaging(3DT1 HR-MRI)data of patients with low-grade stenotic(<50%)atherosclerotic middle cerebral artery(MCA)and subjects with normal MCA,we built a three-dimensional reconstructed WSS model by computational fluid dynamics(CFD)technique.Three-dimensional registration of the CFD model to the HR-MRI was performed with projections based on the resolution and thickness of the images.The relationships between the Wss at each side of the vessel wall and plaque location were analyzed.A total of 94 MCA plaques from 43 patients and 50 normal MCAs were analyzed.In the normal MCAs,WSS was lower at the ventral-inferior wall than at the dorsal-superior wall(proximal segment,p<0.001;middle segment,p<0.001)and lower at the inner wall than at the outer wall of the MCA curve(p<0.001).In atherosclerotic MCAs,similar low Wss regions were observed where plaques developed.The WSS ratio of the ventral-inferior wall to the dorsal-superior wall in atherosclerotic MCAs was lower than that in normal MCAs(p=0.002).The WSS_(inmer-outer)ratio in atherosclerotic MCAs was lower than that in normal MCAs(p=0.002).Low WSS was associated with MCA atherosclerosis formation and occurred mainly at the ventral inferior wall,which was anatomically opposite the orifices of penetrating arteries,and at the inner wall of the MCA curve.Overall,the results were well consistent with the low WSS theory in atherosclerosis formation.The reconstructed WSS model is a promising novel method for assessing an individualized vascular profile once validated by further studies.

Signal Alteration of Substantia Nigra on 3.0T Susceptibility-weighted Imaging in Parkinson's Disease and Vascular Parkinsonism

Recent researches have found that 7 Tesla SWI can detect the alteration of substantia nigra hyperintensity in Parkinson's disease(PD),multiple system atrophy(MSA),and progressive supranuclear palsy(PSP).The aim of this study was to investigate whether 3 Tesla SWI(3T SWI)can visualize anatomical alterations occurring in a hyperintense structure of the substantia nigra in PD and vascular parkinsonism(VP),and whether the evaluation of abnormal signal can be used as a factor in the differential diagnosis of PD and VP.Using 3 Tesla MRI,we evaluated 38 healthy subjects,33 patients with PD and 34 patients with VP.Two blinded readers independently assessed the images.We found that the dorsolateral nigral hyperintensity was absent in 31 of 33 patients with PD and 15 of 34 patients with VP.The dorsolateral nigral hyperintensity was present in 19 of 34 patients with VP and 35 of 38 healthy controls.Group comparisons of absence of dorsolateral nigral hyperintensity revealed significant differences between the patients with PD and those with VP(P<0.001).The sensitivity of SWI for PD was 93.9%and the specificity was 92.1%.Visual assessment of dorsolateral nigral hyperintensity on high-field SWI scans may serve as a new simple diagnostic imaging marker for PD.And our study results indicate that 3T SWI can be used as a tool to identify PD and VP.

High-resolution Magnetic Resonance Imaging of Moyamoya Disease

Objective： To introduce the imaging characteristics of moyamoya disease （MMD） using high-resolution magnetic resonance imaging （HR-MRI） and to discuss the role of HR-MRI in differentiating MMD from other intracranial artery diseases, especially intracranial atherosclerotic disease （ICAD）. Data Sources： This review was based on the data in articles published between 2005 and 2015, which were obtained from PubMed. The keywords included HR-MRI, MMD, ICAD, and intracranial artery diseases. Study Selection： Articles related to HR-MRI for MMD or other intracranial artery diseases were selected for review. Results： There are differences between the characteristic patterns of HR-MRI in MMD and ICAD. MMD is associated with inward remodeling, smaller outer diameters, concentric occlusive lesions and homogeneous signal intensity, while ICAD is more likely to be associated with outward remodeling, normal outer diameters, eccentric occlusive lesions, and heterogeneous signal intensity. Other intracranial artery diseases, such as dissection and vasculitis, also have distinctive characteristics in HR-MRI. HR-MRI may become a useful tool for the differential diagnosis of MMD in the future. Conclusions： HR-MRI of MMD provides a more in-depth understanding of MMD, and it is helpful in evaluating pathological changes in the vessel wall and in differentiating MMD from other intracranial artery steno-occlusive diseases, particularly ICAD.以

Polymeric dual-modal imaging nanoprobe with two-photon aggregation-induced emission for fluorescence imaging and gadolinium-chelation for magnetic resonance imaging

Nanoprobes that offer both fluorescence imaging(FI)and magnetic resonance imaging(MRI)can provide supplementary information and hold synergistic advantages.However,synthesis of such dual-modality imaging probes that simultaneously exhibit tunability of functional groups,high stability,great biocompatibility and desired dual-modality imaging results remains challenging.In this study,we used an amphiphilic block polymer from(ethylene glycol)methyl ether methacrylate(OEGMA)and N-(2-hydroxypropyl)methacrylamide(HPMA)derivatives as a carrier to conjugate a MR contrast agent,Gd-DOTA,and a two-photon fluorophore with an aggregation-induced emission(AIE)effect,TPBP,to construct a MR/two-photon fluorescence dual-modality contrast agent,Gd-DOTA-TPBP.Incorporation of gadolinium in the hydrophilic chain segment of the OEGMA-based carrier resulted in a high r_(1)value for Gd-DOTA-TPBP,revealing a great MR imaging resolution.The contrast agent specifically accumulated in the tumor region,allowing a long enhancement duration for vascular and tumor contrast-enhanced MR imaging.Meanwhile,coupling TPBP with AIE properties to the hydrophobic chain segment of the carrier not only improved its water solubility and reduced its cytotoxicity,but also significantly enhanced its imaging performance in an aqueous phase.Gd-DOTA-TPBP was also demonstrated to act as an excellent fluorescence probe for two-photon-excited bioimaging with higher resolution and greater sensitivity than MRI.Since high-resolution,complementary MRI/FI dual-modal images were acquired at both cellular and tissue levels in tumor-bearing mice after application of Gd-DOTA-TPBP,it has great potential in the early phase of disease diagnosis.

The neuroimaging of neurodegenerative and vascular disease in the secondary prevention of cognitive decline

Structural brain changes indicative of dementia occur up to 20 years before the onset of clinical symptoms. Efforts to modify the disease process after the onset of cognitive symptoms have been unsuccessful in recent years. Thus, future trials must begin during the preclinical phases of the disease before symptom onset. Age related cognitive decline is often the result of two coexisting brain pathologies: Alzheimer's disease(amyloid, tau, and neurodegeneration) and vascular disease. This review article highlights some of the common neuroimaging techniques used to visualize the accumulation of neurodegenerative and vascular pathologies during the preclinical stages of dementia such as structural magnetic resonance imaging, positron emission tomography, and white matter hyperintensities. We also describe some emerging neuroimaging techniques such as arterial spin labeling, diffusion tensor imaging, and quantitative susceptibility mapping. Recent literature suggests that structural imaging may be the most sensitive and cost-effective marker to detect cognitive decline, while molecular positron emission tomography is primarily useful for detecting disease specific pathology later in the disease process. Currently, the presence of vascular disease on magnetic resonance imaging provides a potential target for optimizing vascular risk reduction strategies, and the presence of vascular disease may be useful when combined with molecular and metabolic markers of neurodegeneration for identifying the risk of cognitive impairment.

Reperfusion injury components and manifestations determined by cardiovascular MR and MDCT imaging

Advances in magnetic resonance(MR) and computed tomography(CT) imaging have improved visualization of acute and scar infarct.Over the past decade,there have been and continues to be many significant technical advancements in cardiac MR and multi-detector computed tomography(MDCT) technologies.The strength of MR imaging relies on a variety of pulse sequences and the ability to noninvasively provide information on myocardial structure,function and perfusion in a single imaging session.The recent technical developments may also allow CT technologies to rise to the forefront for evaluating clinical ischemic heart disease.Components of reperfusion injury including myocardial edema,hemorrhage,calcium deposition and microvascular obstruction(MO) have been demonstrated using MR and CT technologies.MR imaging can be used serially and noninvasively in assessing acute and chronic consequences of reperfusion injury because there is no radiation exposure or administration of radioactive materials.MDCT is better suited for assessing coronary artery stenosis and as an alternative technique for as-sessing viability in patients where MR imaging is contraindicated.Changes in left ventricular(LV) volumes and function measured on cine MR are directly related to infarct size measured on delayed contrast enhanced images.Recent MR studies found that transmural infarct,MO and peri-infarct zone are excellent predictors of poor post-infarct recovery and mortality.Recent MR studies provided ample evidence that growth factor genes and stem cells delivered locally have beneficial effects on myocardial viability,perfusion and function.The significance of deposited calcium in acute infarct detected on MDCT requires further studies.Cardiac MR and MDCT imaging have the potential for assessing reperfusion injury components and manifestations.

igh-resolution Magnetic Resonance Vessel Wall Imaging for Intracranial Arterial Stenosis

Objective： To discuss the feasibility and clinical value of high-resolution magnetic resonance vessel wall imaging （HRMR VWI） for intracranial arterial stenosis. Date Sources： We retrieved information from PubMed database up to December 2015, using various search terms including vessel wall imaging （VWI）, high-resolution magnetic resonance imaging, intracranial arterial stenosis, black blood, and intracranial atherosclerosis. Study Selection： We reviewed peer-reviewed articles printed in English on imaging technique of VWI and characteristic findings of various intracranial vasculopathies on VWI. We organized this data to explain the value of VWI in clinical application. Results： VWI with black blood technique could provide high-quality images with submillimeter voxel size, and display both the vessel wall and lumen of intracranial artery simultaneously. Various intracranial vasculopathies （atherosclerotic or nonatherosclerotic） had differentiating features including pattern of wall thickening, enhancement, and vessel remodeling on VWI. This technique could be used for determining causes of stenosis, identification of stroke mechanism, risk-stratifying patients, and directing therapeutic management in clinical practice. In addition, a new morphological classification based on VWI could be established for predicting the efficacy of endovascular therapy. Conclusions： This review highlights the value of HRMR VWI for discrimination of different intracranial vasculopathies and directing therapeutic management.

Distribution of wall shear stress in carotid plaques using magnetic resonance imaging and computational fluid dynamics analysis： a preliminary study

Background Wall shear stress is an important factor in the destabilization of atherosclerotic plaques. The purpose of this study was to assess the distribution of wall shear stress in advanced carotid plaques using high resolution magnetic resonance imaging and computational fluid dynamics.Methods Eight diseased internal carotid arteries in seven patients were evaluated. High resolution magnetic resonance imaging was used to visualize the plaque structures, and the mechanic stress in the plaque was obtained by combining vascular imaging post-processing with computational fluid dynamics.Results Wall shear stresses in the plaques in all cases were higher than those in control group. Maximal shear stresses in the plaques were observed at the top of plaque hills, as well as the shoulders of the plaques. Among them,the maximal shear stress in the ruptured plaque was observed in the rupture location in three cases and at the shoulder of fibrous cap in two cases. The maximal shear stress was also seen at the region of calcification, in thrombus region and in the thickest region of plaque in the other three cases, respectively.Conclusion Determination of maximal shear stress at the plaque may be useful for predicting the rupture location of the plaque and may play an important role in assessing plaque vulnerability.

Blood Oxygenation Level-dependent Magnetic Resonance Imaging of Breast Cancer： Correlation with Carbonic Anhydrase IX and Vascular Endothelial Growth Factor

Background： Blood oxygenation level-dependent magnetic resonance imaging （BOLD-MRI） is a functional MRI technique which involves using the paramagnetic properties of deoxyhemoglobin to image the local tissue oxygen concentration. The purpose of this study was to investigate whether BOLD-MRI could evaluate hypoxia and angiogenesis of breast invasive ductal carcinoma （IDC）. Methods： Ninety-eight female patients with IDC were retrospectively included in this research. All patients underwent breast BOLD-MRI at 3.0 T before surgery. R2＊ values of BOLD-MR1 were measured. The expression of carbonic anhydrase IX （CA IX） and vascular endothelial growth factor （VEGF） was analyzed by immunohistochemistry. Spearman＇s correlation analysis was used to correlate R2＊ value with CA IX and VEGF levels. Results： Heterogeneous intensity on BOLD-MRI images was the main finding of IDCs. The mean R2＊ value was 52.8 ± 18.6 Hz. The R2＊ values in patients with axillary lymph node metastasis were significantly higher than the R2＊ values in patients without axillary lymph node metastasis （t = 2.882, P = 0.005）. R2＊ values increased with CA IX level and positively correlated with the level of CA 1X （r = 0.616, P 〈 0.001）; however, R2＊ value had no significantly correlation with the level of VEGF （r = 0.110, P = 0.281）. Conclusion： B OLD-MRI could noninvasively evaluate chronic hypoxia of IDC, but not angiogenesis.

What can imaging tell us about cognitive impairment and dementia?

Dementia is a contemporary global health issue with far reaching consequences, not only for affected individuals and their families, but for national and global socio-economic conditions. The hallmark feature of dementia is that of irreversible cognitive decline, usually affecting memory, and impaired activities of daily living. Advances in healthcare worldwide have facilitated longer life spans, increasing the risks of developing cognitive decline and dementia in late life. Dementia remains a clinical diagnosis. The role of structural and molecular neuroimaging in patients with dementia is primarily supportive role rather than diagnostic, American and European guidelines recommending imaging to exclude treatable causes of dementia, such as tumor, hydrocephalus or intracranial haemorrhage, but also to distinguish between different dementia subtypes, the commonest of which is Alzheimer&#x02019;s disease. However, this depends on the availability of these imaging techniques at individual centres. Advanced magnetic resonance imaging (MRI) techniques, such as functional connectivity MRI, diffusion tensor imaging and magnetic resonance spectroscopy, and molecular imaging techniques, such as 18F fluoro-deoxy glucose positron emission tomography (PET), amyloid PET, tau PET, are currently within the realm of dementia research but are available for clinical use. Increasingly the research focus is on earlier identification of at risk preclinical individuals, for example due to family history. Intervention at the preclinical stages before irreversible brain damage occurs is currently the best hope of reducing the impact of dementia.

Theranostic applications:Non-ionizing cellular and molecular imaging through innovative nanosystems for early diagnosis and therapy

Modern medicine is expanding the possibilities of receiving "personalized" diagnosis and therapies,providing minimal invasiveness,technological solutions based on non-ionizing radiation,early detection of pathologies with the main objectives of being operator independent and with low cost to society.Our research activities aim to strongly contribute to these trends by improving the capabilities of current diagnostic imaging systems,which are of key importance in possibly providing both optimal diagnosis and therapies to patients.In medical diagnostics,cellular imaging aims to develop new methods and technologies for the detection of specific metabolic processes in living organisms,in order to accurately identify and discriminate normal from pathological tissues.In fact,most diseases have a "molecular basis" that detected through these new diagnostic methodologies can provide enormous benefits to medicine.Nowadays,this possibility is mainly related to the use of Positron Emission Tomography,with an exposure to ionizing radiation for patients and operators and with extremely high medical diagnosticscosts.The future possible development of non-ionizing cellular imaging based on techniques such as Nuclear Magnetic Resonance or Ultrasound,would represent an important step towards modern and personalized therapies.During the last decade,the field of nanotechnology has made important progress and a wide range of organic and inorganic nanomaterials are now available with an incredible number of further combinations with other compounds for cellular targeting.The availability of these new advanced nanosystems allows new scenarios in diagnostic methodologies which are potentially capable of providing morphological and functional information together with metabolic and cellular indications.