Dynamic Contrast-Enhanced Perfusion MR Imaging Measurements of Endothelial Permeability: Differentiation between Atypical and Typical Meningiomas

BACKGROUND: AND PURPOSE: The measurement of relative cerebral blood volume (rCBV) and the volume transfer constant (K(trans)) by means of dynamic contrast-enhanced (DCE) perfusion MR imaging (pMRI) can be useful in characterizing brain tumors. The purpose of our study was to evaluate the utility of these measurements in differentiating typical meningiomas and atypical meningiomas. METHODS: Fifteen patients with pathologically confirmed typical meningiomas and seven with atypical meningiomas underwent conventional imaging and DCE pMRI before resection.rCBV measurements were calculated by using standard intravascular

MR IMAGING ASSESSMENT OF IRREGULAR SHRINKAGE OF TUMOR MORPHOLOGY AND VOLUME IN CERVICAL CANCER DURING RADIATION THERAPY

To study the clinical significance of the morphological and volume changes in cervical cancer during an ongoing course of radiation therapy (RT) using MR imaging. Methods: Serial MR imaging examinations were performed in 60 advanced cervical cancer patients. MR imaging was obtained at the start of RT, at 20-25 Gy (2-2.5 weeks of RT), at 45-50 Gy (4-5 weeks of RT), and 1-2 month post-RT. Tumor morphology was classified qualitatively as well-defined (round/oval with a well-demarcated smooth margin) vs. lobulated vs. irregular and tumor volume was assessed in each serial MR examination independently by ROI volumetry and diameter volumetry. ROI volumetry was traced on the computer workstation with a trackball in each sagittal T2-weighted image and calculated by the summation of all tumor areas in each slice and multiplication by the slice profile. Diameter volumetry was to measure the largest three orthogonal tumor diameters in each orthogonal measurement plane and calculate as an ellipsoid formula (V=d1 x d2 x d3 x p/6). Serial tumor volume was compared between the two measurement methods. Results: The proportion of lobulated and irregular tumors increased early during RT and declined lately post-RT (68% pre-RT, 80% at 2-2.5 weeks of RT, 72% at 4-5 weeks of RT, 33% post-RT). Accordingly, ROI volumetry and diameter volumetry correlated well pre-RT (r1=0.89) and post-RT (r4=0.80), but poorly during RT (r2 = 0.17 at 2-2.5 weeks of RT, r3 = 0.69 at 4-5 weeks of RT). Conclusions: Cervical cancers regress in a non-uniform fashion during RT and undergo increasingly irregular shrinkage. Measurement with ROI volumetry techniques, which can optimally measure irregular volumes, provides better assessment of radiation response during treatment than diameter volumetry.

Progress in magnetic resonance imaging of the glymphatic system

The glymphatic system(GS)is a newly discovered brain anatomy.Its discovery improves our understanding of brain fluid flow and waste removal paths and provides an anatomical basis for the flow of cerebral interstitial fluid(ISF)and cerebrospinal fluid(CSF).GS occurs through a normal exchange within perivascular space(PVS),facilitating the elimination of metabolic wastes generated by nerve cells from the brain.Therefore,the GS is mainly responsible for the removal of metabolic waste.Reduced GS activity has been observed to be associated with central nervous system disorders such as cerebral small vessel disease(CSVD)and neurodegenerative diseases.Its activity is expected to be an indicator for diagnosing diseases and predicting their prognosis.This review introduces the magnetic resonance imaging(MRI)technology related to the GS suitable for clinical use and the difference in the system's activity in normal and abnormal states.Through a summary of previous research,imaging methods suitable for monitoring the activity of the GS in the clinic were proposed,and their diagnostic effect on different brain disorders was analyzed.This review aims to clarify ideas for the clinical translation of basic research focusing on GS and provide future clinical research directions and perspectives.

Characteristic MR imaging findings and surgical treatment of cavernous hemangiomas in cavernous sinus

Objective To analyze the imaging character and surgical therapy of cavernous hemangiomas in cavernous sinus(CSHs).Methods From 2001 to 2008,13 patients with CSHs were surgically treated in our department. The diameters of CSHs varied from 3. 5 cm to 6. 0 cm. Results All the patients were operated on with no mortality.

CT and MRI diagnosis of hepatic epithelioid hemangioendothelioma

BACKGROUND: Hepatic epithelioid hemangioendothelioma (EHE) is a rare, low-grade malignant vascular tumor. Although its unusual imaging and pathologic findings are being recognized with increasing frequency, diagnosis is still difficult. This study aimed to analyze the CT and MRI features of hepatic EHE with a pathological study in order to improve the diagnostic accuracy and knowledge of this disease in daily practice. METHODS: Nine patients with hepatic EHE confirmed pathologically underwent plain and dynamic contrast-enhanced multi-detector row CT examination. Of these patients, four underwent additional MRI (plain Ti-weighted imaging (T1WI), T2-weighted imaging (T2WI), and dynamic contrast-enhanced scanning) and one had selective hepatic arteriography. The imaging findings were reviewed retrospectively together with the pathological results. RESULTS: A total of 79 lesions, ranging from 3.0 to 44.6 mm in maximum diameter, with an average of 16.8 +/- 7.1 mm, were found in various segments of the liver. Thirty of the 79 lesions grew adjacent to the hepatic capsule. In the 4 patients receiving MRI, 39 lesions were found with low signal intensity on unenhanced T1WI and intermediate to high signal intensity on T2WI. The 'capsular retraction' sign was found in all the 4 patients. Nine of the 39 lesions showed the 'halo' sign after contrast enhancement on MRI. Of the 79 lesions (hypodense nodules) in the 9 patients shown by unenhanced plain CT, 26 were confluent. Calcification was found in 2 patients and the 'capsular retraction' sign in 7. Thirty-eight of the 79 lesions demonstrated the 'halo' sign after contrast enhancement on CT, and this sign was more clearly demonstrated in the portal venous phase. In one patient, selective hepatic arteriography showed patchy stain in the peripheral liver parenchyma with small vessels around them. Histology in all patients revealed proliferation of abnormal fibrous tissue and vessel-like structures scattered with irregular epithelioid cells having a signet ring-like structure. Immunohistochemically, all patients were positive for CD34, 4 were positive for CD31, and 3 were positive for factor VIII-related antigen. CONCLUSIONS: Hepatic EHE may manifest as solitary or diffuse nodular lesions with a predilection for peripheral subcapsular growth and nodular confluence, together with the 'halo' and 'capsular retraction' signs. These imaging findings can help to improve the diagnostic accuracy of this rare hepatic tumor. (Hepatobiliary Pancreat Dis Int 2010; 9: 154-158)

MRI shows clodronate-liposomes attenuating liver injury in rats with severe acute pancreatitis

BACKGROUND: Studies have revealed that macrophages play an important role in the development of severe acute pancreatitis (SAP). Activated macrophages can lead to a systemic inflammatory response, induce lipid peroxidation, impair membrane structure, result in injury to the liver and the other extrahepatic organs, and eventually result in multiple organ dysfunction syndrome by promoting excessive secretion of cytokines. Liver injury can further aggravate the systemic inflammatory response and increase mortality by affecting the metabolism of toxins and the release of excessive inflammatory mediators. Clodronate is a synthetic bisphosphonate, which is often used for treating bone changes caused by osteoporosis and other factors. In the current study, we created liposomes containing superparamagnetic iron oxide particles (SPIOs) for macrophage labeling and magnetic resonance imaging, using a novel method that can bind the clodronate to induce apoptosis and deplete macrophages. METHODS: Superparamagnetic Fe(3)O(4) nanoparticles were prepared by chemical coprecipitation. SPIO-containing liposomes and SPIO-clodronate-containing liposomes were prepared by the thin film method. SAP models were prepared by injection of sodium taurocholate (2 ml/kg body weight) into the subcapsular space of the pancreas. Sprague-Dawley rats were randomly divided into a control group, a SAP plus SPIO-liposome group, and a SAP plus SPIO-clodronate-containing group. Two and six hours after SAP models were available, T2-weighted MRI scans (in the same plane) of the livers of rats in each group were performed. At the end of the scans, 2 ml of blood was taken from the superior mesenteric vein to measure the levels of serum amylase, ALT, AST, TNF-alpha, and IL-6. Pathological changes in the liver and pancreas were assessed. RESULTS: Transmission electron microscopy showed that the liposomes had a uniform size. No pathological changes in the pancreata of rats in the control group were noted. The pathological changes in the pancreata and livers of rats in the SAP plus SPIO-clodronate-containing liposome group were milder than those in the SAP plus SPIO-liposome group. The MRI signal intensity of the livers in the SAP plus SPIO-liposome and SAP plus SPIO-clodronate-containing groups was significantly lower than that in the control group. There were significant changes in the two experimental groups (P<0.01). In addition, the levels of serum amylase, ALT, AST, TNF-alpha, and IL-6 in rats in the SAP plus SPIO-liposome group were higher than those in the control group (P<0.01), while the corresponding levels in the SPIO-clodronate-containing liposome group were significantly lower than those in the SAP plus SPIO-liposome group (P<0.01). CONCLUSION: Clodronate-containing liposomes protect against liver injury in SAP rats, and SPIO can be used as a tracer for MRI examination following liver injury in SAP rats. (Hepatobiliary Pancreat Dis Int 2010; 9: 192-200)

The Usefulness of Magnetic Resonance Imaging in the Preoperative Study and Postoperative Control in the Laparoscopic Treatment of the Incisional Hernia

Background and Objectives: The aim of this study is to evaluate the usefulness of Magnetic Resonance Imaging (MRI) for planning surgery and postoperative control of complex cases of abdominal wall hernia. Methods: Included in a prospective data base with more than 350 patients treated in two centers, a prospective study over ten patients with complex incisional hernias was designed. In all cases, preoperative diagnosis study and postoperative imaging control by MR Imaging were established. In the early and late follow-up controls, local and general complications were specifically noted and studied by MRI in each case. Results: The preoperative MRI was effective method for an adequate understanding of the defects and hernia sack content. In the postoperative control, the MRI was useful in the follow-up of the mesh integration, detection of complications and diagnosis of the relapsing. Conclusion: In our experience the MRI test is specially recommended in the preoperative workup of complex cases of incisional hernia.

It’s Time for New Insights into Renovascular Hypertension at the Molecular Level

At the cellular level, reduced kidney perfusion in atherosclerotic renal arthery disease (ARVD), induces hypoxia, activation of the renin-angiotensin-aldosterone system (RAAS) and cytokine activation. Impaired blood flow in the kidneys creates a microenvironment triggering significant cytokine production, contributing to vascular damage and endothelial disfunction. Interactions between cytokines and endothelial, glomerular, and tubular cells often result in increased vessel permeability, and fibrosis, and contribute to the development of chronic kidney disease (CKD). Molecules such as endothelins, prostaglandins, and nitric oxide play a crucial role at the molecular level. The imbalance between vasoconstrictor and vasodilator factors contributes to vascular dysfunction. Oxidative stress and inflammatory processes at the cellular level contribute to endothelial damage and structural changes in blood vessels. Mineralocorticoid receptor antagonists (MRAs) therapy in the context of ARVD holds promise in reducing fibrosis, promoting angiogenesis and enhancing overall outcomes in patients with this pathology. Recent data also indicates the antioxidative, anti-inflammatory, and antifibrotic effects of SGLT2 inhibitors. They reduce oxidative stress caused by hypoxic conditions and enhance renal perfusion, contributing to the preservation of cellular function. Studies employing Blood Oxygen Level-Dependent (BOLD) imaging have identified adaptations to reduced blood flow, volume, and glomerular filtration rate in post-stenotic kidneys that preserve oxygenation in the medulla and cortex during medical therapy. Data from the literature indicate that despite the partial recovery of renal hypoxia and restoration of blood flow after revascularization, inflammatory cytokines and injury biomarkers remain elevated, and the glomerular filtration rate (GFR) does not recover in ARVD. Restoration of vascular patency alone has failed to reverse tubulointerstitial damage and partially explains the limited clinical benefit of renal stenting. Considering these findings, BOLD MR imaging emerges as a technique capable of providing insights into the critical juncture of irreversibility in ARVD. However, further research is needed to monitor renal hypoxia following renal artery stenting and the inflammatory response over an extended period in conjunction with optimal therapy involving MRAs and SGLT2 agonists. The aim of research at the molecular level enables the identification of potential therapeutic modalities targeting specific molecular pathways, opening the door to innovative approaches in treating renovascular hypertension.

Real-time SERS monitoring anticancer drug release along with SERS/MR imaging for pH-sensitive chemo-phototherapy

In situ and real-time monitoring of responsive drug release is critical for the assessment of pharmacodynamics in chemotherapy.In this study,a novel pH-responsive nanosystem is proposed for real-time monitoring of drug release and chemo-phototherapy by surface-enhanced Raman spectroscopy(SERS).The Fe3O4@Au@Ag nanoparticles(NPs)deposited graphene oxide(GO)nanocomposites with a high SERS activity and stability are synthesized and labeled with a Raman reporter 4-mercaptophenylboronic acid(4-MPBA)to form SERS probes(GO-Fe3O4@Au@Ag-MPBA).Furthermore,doxorubicin(DOX)is attached to SERS probes through a pH-responsive linker boronic ester(GO-Fe3O4@Au@Ag-MPBA-DOX),accompanying the 4-MPBA signal change in SERS.After the entry into tumor,the breakage of boronic ester in the acidic environment gives rise to the release of DOX and the recovery of 4-MPBA SERS signal.Thus,the DOX dynamic release can be monitored by the real-time changes of 4-MPBA SERS spectra.Additionally,the strong T2 magnetic resonance(MR)signal and NIR photothermal transduction efficiency of the nanocomposites make it available for MR imaging and photothermal therapy(PTT).Altogether,this GO-Fe3O4@Au@Ag-MPBA-DOX can simultaneously fulfill the synergistic combination of cancer cell targeting,pH-sensitive drug release,SERS-traceable detection and MR imaging,endowing it great potential for SERS/MR imaging-guided efficient chemo-phototherapy on cancer treatment.

Quantitative comparisons between relaxation enhanced compressed sensing 3D MERGE and conventional 3D MERGE for vessel wall imaging in equal scan time: preliminary studies

In this study, we quantitatively compared relaxation enhanced compressed sensing(RECS-3D MERGE) with conventional 3D MERGE techniques on blood suppression efficiency, wall-lumen contrast and plaque burden measurement for carotid atherosclerotic imaging in equal scan time. Twelve patients were recruited in the study. RECS-3D MERGE and conventional 3D MERGE were implemented. 2D DIR-FSE was carried out as a reference standard. The lumen signal-to-tissue ratio(STR) was used as the quantitative measure of blood suppression efficiency. The contrast-to-tissue ratio(CTR) was used as the quantitative measure of wall-lumen contrast. Vessel lumen area(LA) and wall area(WA) were measured for morphological comparisons. The lumen STR of RECS-3D MERGE was significantly lower than that of 3D MERGE while the wall-lumen CTR of RECS-3D MERGE was significantly higher. There were no significant differences in plaque burden measurements between RECS-3D MERGE and 2D DIR-FSE. For comparison between conventional 3D MERGE and 2D DIR-FSE, there were no significant differences in LA measurement. However, the WA of 3D MERGE was significantly larger. The RECS-3D MERGE sequence achieved more sufficient blood suppression and higher image contrast without prolonging the scan time. These improvements lead to more accurate morphological measurements of carotid atherosclerotic imaging.

Nanogels as Contrast Agents for Molecular Imaging

Nanogels （NGs） as soft nanosized materials have gained a variety of interests in biomedical fields. The versatile NG scaffolds with 3-dimensional spherical shape, high loading efficiency, tunable surface functionalization, and excellent biocompatibility afford their uses as carrier to load mono- or multi-mode molecular imaging contrast agents （CAs）. This review summarizes the synthesis routes and applications of NGs as CAs for molecular imaging applications including magnetic resonance （MR）, computed tomography （CT）, radionuclide, optical, and dual/mul- ti-modality imaging.

Synthesis of bifunctional Gd_2O_3:Eu^(3+) nanocrystals and their applications in biomedical imaging

Ultrafine Gd2O3：Eu3＋nanocrystals were successfully prepared by a simple reverse microemulsion method and subsequent calcination. Their structural, optical and magnetic properties were investigated using scanning electron microscopy （SEM）, transmis-sion electron microscopy （TEM）, X-ray diffraction （XRD）, Fourier transform infrared （FTIR）, photoluminescence （PL）, and magnetic property measurement system （MPMS）. The amorphous Gd2（CO3）3：Eu3＋colloidal spheres were proved as an intermediate product, and gradually transformed into crystallized Gd2O3：Eu3＋with average diameter less than 100 nm. The paramagnetic property of the synthesized Gd2O3：Eu3＋nanocrystals were confirmed with its linear hysteresis plot （M-H）. And Gd2O3：Eu3＋nanocrystals showed high contrast T1-enhancing modality due to the presence of the Gd3＋ ions onto the particle surface. In addition, the application of the Gd2O3：Eu3＋nanocrystals as biotag for cell labeling was reported, red fluorescence from Eu3＋ions observed by fluorescence micros-copy showed that the nanocrystals could permeate the cell membrane. Cytotoxicity studies of the Gd2O3：Eu3＋nanocrystals showed no adverse effect on cell viability, evidencing their high biological compatibility. Therefore, the nanoprobe formed from Gd2O3：Eu3＋nanocrystals provided the dual modality of optical and magnetic resonance imaging.

Engineered macrophage-biomimetic versatile nanoantidotes for inflammation-targeted therapy against Alzheimer’s disease by neurotoxin neutralization and immune recognition suppression

Immune recognition of excessive neurotoxins by microglia is a trigger for the onset of neuroinflammation in the brain,leading to neurodegeneration in Alzheimer’s disease(AD).Blocking active recognition of microglia while removing neurotoxins holds promise for fundamentally alleviating neurotoxin-induced immune responses,but is very challenging.Herein,an engineered macrophage-biomimetic versatile nanoantidote(OT-Lipo@M)is developed for inflammation-targeted therapy against AD by neurotoxin neutralization and immune recognition suppression.Coating macrophage membranes can not only endow OT-Lipo@M with anti-phagocytic and inflammation-tropism capabilities to target inflammatory lesions in AD brain,but also efficiently reduce neurotoxin levels to prevent them from activating microglia.The loaded oxytocin(OT)can be slowly released to downregulate the expression of immune recognition site Toll-like receptor 4(TLR4)on microglia,inhibiting TLR4-mediated pro-inflammatory signalling cascade.Benefiting from this two-pronged immunosuppressive strategy,OT-Lipo@M exhibits outstanding therapeutic effects on ameliorating cognitive deficits,inhibiting neuronal apoptosis,and enhancing synaptic plasticity in AD mice,accompanied by the delayed hippocampal atrophy and brain microstructural disruption by in vivo 9.4T MR imaging.This work provides new insights into potential AD therapeutics targeting microglia-mediated neuroinflammation at the source.

Dual-targeted nanoformulation with Janus structure for synergistic enhancement of sonodynamic therapy and chemotherapy

The accurate delivery of nanoparticles and organic small molecule drugs remains a serious challenge in nanoparticle-based tumor therapy.Dual-targeted therapy combining tumor cell targeting and organelle targeting is an effective solution.Here,an anticancer nanoformulation accurate delivery system was prepared using hyaluronic acid (HA) targeting CD44 receptors on the surface of tumor cells and IR780iodine (IR780) targeting mitochondrial for delivery.The system is based on an ultra-small Janus structured inorganic sensitizer TiO_(2-x)@NaGdF_(4) nanoparticles (TN NPs) prepared by one-step pyrolysis,further loaded with organic small molecule acoustic sensitizer IR780 and mitochondrial hexokinase Ⅱ inhibitor lonidamine (LND),followed by encapsulation of HA.Ultra-small size nanoparticles exhibit strong tissue penetration,tumor inhibition and in vivo metabolism.Under ultrasound radiation,TN NPs and IR780could produce a synergistic effect,effectively increased the efficiency of reactive oxygen species (ROS)production.Meanwhile,the released IR780 could smoothly target the mitochondria,and the ROS produced by IR780 can destroy the mitochondrial structure and disrupt the mitochondrial respiration.LND could inhibit the energy metabolism of tumor cells by reducing the activity of hexokinase Ⅱ (HK Ⅱ),which further accelerates the process of apoptosis.Furthermore,since the Janus structure allows the integration of multifunctional components into a single system,TN NPs can not only serve as an acoustic sensitizer to generate ROS,but the Gd element contained can also act as the nuclear magnetic resonance (MR)imaging contrast agent,suggesting that the nanoformulation can enable imaging-guided diagnosis and therapy.In conclusion,a new scheme to enhance sonodynamic therapy (SDT) and chemotherapy synergistically is proposed here based on ultra-small dual-targeted nanoformulation with Janus structure in the ultrasound radiation environment.