Activatable UCL/CT/MR-enhanced in vivo imaging-guided radiotherapy and photothermal therapy.

Although sophisticated radiotherapy (RT) technology has been widely applied in clinical oncotherapy, unsatisfactory therapeutic effects due to hypoxic tumor microenvironments and complications are still prevalent. Herein, copper sulphide nanoparticles (CuS NPs) wrapped on the surface of upconversion nanoparticles (UCNPs) via manganese dioxide (MnO2) coatings were synthesized for O2 self-supplementing and enhanced combinational RT/photothermal therapy (PTT). In our design, the nanoplatforms can be rapidly enriched at tumor sites by the enhanced permeability and retention (EPR) effect and respond to the tumor microenvironment. The surface MnO2 coatings can interact with over-expressed H2O2 in tumors and cause an abundant generation of oxygen for hypoxic improvement, leading to an enhanced RT. More importantly, by irradiation with near-infrared light, the scattered CuS NPs can convert light energy into heat to destroy tumor cells and reinforce the therapeutic effects of RT. Furthermore, these NPs also displayed excellent performances in upconversion fluorescence imaging (UCL), computerized tomographic (CT) scanning and magnetic resonance imaging (MRI), demonstrating a potential imaging-guided cancer therapy system.

Sodium Cholate Bile Acid-Stabilized Ferumoxytol-Doxorubicin-Lipiodol Emulsion for Transcatheter Arterial Chemoembolization of Hepatocellular Carcinoma.

PURPOSE: To develop bile acid-stabilized multimodal magnetic resonance (MR) imaging and computed tomography (CT)-visible doxorubicin eluting lipiodol emulsion for transarterial chemoembolization of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Ferumoxytol, a US Food and Drug Administration-approved iron oxide nanoparticle visible under MR imaging was electrostatically complexed with doxorubicin (DOX). An amphiphilic bile acid, sodium cholate (SC), was used to form a stable dispersion of ferumoxytol-DOX complex in lipiodol emulsion. Properties of the fabricated emulsion were characterized in various component ratios. Release kinetics of DOX were evaluated for the chemoembolization applications. Finally, in vivo multimodal MR imaging/CT imaging properties and potential therapeutic effects upon intra-arterial (IA) infusion bile acid-stabilized ferumoxytol-DOX-lipiodol emulsion were evaluated in orthotopic McA-Rh7777 HCC rat models. RESULTS: DOX complexed with ferumoxytol through electrostatic interaction. Amphiphilic SC bile acid at the interface between the aqueous ferumoxytol-DOX complexes and lipiodol enabled a sustained DOX release (17.2 ± 1.6% at 24 hours) at an optimized component ratio. In McA Rh7777 rat HCC model, IA-infused emulsion showed a significant contrast around tumor in both T2-weighted MR imaging and CT images (P = .044). Hematoxylin and eosin and Prussian blue staining confirmed the local deposition of IA-infused SC bile acid-stabilized emulsion in the tumor. The deposited emulsion induced significant increases in TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) stain-positive cancer cell apoptosis compared to those in a group treated with the nonstabilized emulsion. CONCLUSIONS: SC bile acid-stabilized ferumoxytol-DOX-lipiodol emulsion demonstrated sustained drug release and multimodal MR imaging/CT imaging capabilities. The new lipiodol-based formulation may enhance the therapeutic efficacy of chemoembolization in HCC.

Molecular MRI of the Immuno-Metabolic Interplay in a Rabbit Liver Tumor Model: A Biomarker for Resistance Mechanisms in Tumor-targeted Therapy?

Background The immuno-metabolic interplay has gained interest for determining and targeting immunosuppressive tumor micro-environments that remain a barrier to current immuno-oncologic therapies in hepatocellular carcinoma. Purpose To develop molecular MRI tools to reveal resistance mechanisms to immuno-oncologic therapies caused by the immuno-metabolic interplay in a translational liver cancer model. Materials and Methods A total of 21 VX2 liver tumor-bearing New Zealand white rabbits were used between October 2018 and February 2020. Rabbits were divided into three groups. Group A (n = 3) underwent intra-arterial infusion of gadolinium 160 (160Gd)-labeled anti-human leukocyte antigen-DR isotope (HLA-DR) antibodies to detect antigen-presenting immune cells. Group B (n = 3) received rhodamine-conjugated superparamagnetic iron oxide nanoparticles (SPIONs) intravenously to detect macrophages. These six rabbits underwent 3-T MRI, including T1- and T2-weighted imaging, before and 24 hours after contrast material administration. Group C (n = 15) underwent extracellular pH mapping with use of MR spectroscopy. Of those 15 rabbits, six underwent conventional transarterial chemoembolization (TACE), four underwent conventional TACE with extracellular pH-buffering bicarbonate, and five served as untreated controls. MRI signal intensity distribution was validated by using immunohistochemistry staining of HLA-DR and CD11b, Prussian blue iron staining, fluorescence microscopy of rhodamine, and imaging mass cytometry (IMC) of gadolinium. Statistical analysis included Mann-Whitney U and Kruskal-Wallis tests. Results T1-weighted MRI with 160Gd-labeled antibodies revealed localized peritumoral ring enhancement, which corresponded to gadolinium distribution detected with IMC. T2-weighted MRI with SPIONs showed curvilinear signal intensity representing selective peritumoral deposition in macrophages. Extracellular pH-specific MR spectroscopy of untreated liver tumors showed acidosis (mean extracellular pH, 6.78 ± 0.09) compared with liver parenchyma (mean extracellular pH, 7.18 ± 0.03) (P = .008) and peritumoral immune cell exclusion. Normalization of tumor extracellular pH (mean, 6.96 ± 0.05; P = .02) using bicarbonate during TACE increased peri- and intratumoral immune cell infiltration (P = .002). Conclusion MRI in a rabbit liver tumor model was used to visualize resistance mechanisms mediated by the immuno-metabolic interplay that inform susceptibility and response to immuno-oncologic therapies, providing a therapeutic strategy to restore immune permissiveness in liver cancer. © RSNA, 2020 Online supplemental material is available for this article.

Spectral CT Imaging-Based Quantification of Iodized Oil Retention following Chemoembolization: Phantom and Animal Studies.

PURPOSE: To evaluate accuracy of iodine quantification using spectral CT and the potential of quantitative iodized oil analysis as an imaging biomarker of chemoembolization. MATERIALS AND METHODS: A phantom of an artificial liver with 6 artificial tumors containing different amounts of iodized oil (0-8 vol%) was scanned by spectral CT, and iodized oil density (mg/mL) and Hounsfield unit (HU) values were measured. In addition, VX2 hepatoma was induced in 23 rabbits. After chemoembolization using iodized oil chemoemulsion, the rabbits were scanned by spectral CT. The accumulation of iodized oil in the tumor was quantified in terms of iodized oil density and HUs, and the performances in predicting a pathologic complete response (CR) were evaluated by receiver operating characteristic curve analyses. RESULTS: The mean difference between true iodine densities and spectral image-based measurements was 0.5 mg/mL. Mean HU values were highly correlated with mean iodine density (r2 = 1.000, P < .001). In the animal study, a pathologic CR was observed in 17 of 23 rabbits (73.9%). The range of area under the curve values of iodine and HU measurements was 0.863-0.882. A tumoral iodine density of 3.57 mg/mL, which corresponds to 0.7 vol% iodized oil in the tumor, predicted a pathologic CR with a sensitivity of 70.6% and a specificity of 100.0%. CONCLUSIONS: Spectral CT imaging has a potential to predict tumor responses after chemoembolization by quantitatively assessing iodized oil in targets.

Molecular Imaging of Extracellular Tumor pH to Reveal Effects of Locoregional Therapy on Liver Cancer Microenvironment.

PURPOSE: To establish magnetic resonance (MR)-based molecular imaging paradigms for the noninvasive monitoring of extracellular pH (pHe) as a functional surrogate biomarker for metabolic changes induced by locoregional therapy of liver cancer. EXPERIMENTAL DESIGN: Thirty-two VX2 tumor-bearing New Zealand white rabbits underwent longitudinal imaging on clinical 3T-MRI and CT scanners before and up to 2 weeks after complete conventional transarterial chemoembolization (cTACE) using ethiodized oil (lipiodol) and doxorubicin. MR-spectroscopic imaging (MRSI) was employed for pHe mapping. Multiparametric MRI and CT were performed to quantify tumor enhancement, diffusion, and lipiodol coverage of the tumor posttherapy. In addition, incomplete cTACE with reduced chemoembolic doses was applied to mimic undertreatment and exploit pHe mapping to detect viable tumor residuals. Imaging findings were correlated with histopathologic markers indicative of metabolic state (HIF-1α, GLUT-1, and LAMP-2) and viability (proliferating cell nuclear antigen and terminal deoxynucleotidyl-transferase dUTP nick-end labeling). RESULTS: Untreated VX2 tumors demonstrated a significantly lower pHe (6.80 ± 0.09) than liver parenchyma (7.19 ± 0.03, P < 0.001). Upregulation of HIF-1α, GLUT-1, and LAMP-2 confirmed a hyperglycolytic tumor phenotype and acidosis. A gradual tumor pHe increase toward normalization similar to parenchyma was revealed within 2 weeks after complete cTACE, which correlated with decreasing detectability of metabolic markers. In contrast, pHe mapping after incomplete cTACE indicated both acidic viable residuals and increased tumor pHe of treated regions. Multimodal imaging revealed durable tumor devascularization immediately after complete cTACE, gradually increasing necrosis, and sustained lipiodol coverage of the tumor. CONCLUSIONS: MRSI-based pHe mapping can serve as a longitudinal monitoring tool for viable tumors. As most liver tumors are hyperglycolytic creating microenvironmental acidosis, therapy-induced normalization of tumor pHe may be used as a functional biomarker for positive therapeutic outcome.

Transarterial Infusion of iRGD-Modified ZrO2 Nanoparticles with Lipiodol Improves the Tissue Distribution of Doxorubicin and Its Antitumor Efficacy.

PURPOSE: To evaluate the effect of transarterial infusion of iRGD-modified and doxorubicin-loaded zirconia-composite nanoparticles (R-DZCNs) with lipiodol in the improvement of the distribution of doxorubicin (DOX) in liver tumors and its antitumor efficacy. MATERIALS AND METHODS: The effect of R-DZCNs was evaluated in vitro by tumor cellular uptake and cytotoxicity assays. For the in vivo study, DOX distribution and antitumor efficiency were assessed. In the DOX distribution study, VX2 tumor-bearing rabbits received transarterial infusion of lipiodol with DOX, doxorubicin-loaded zirconia-composite nanoparticles (DZCNs), or R-DZCNs, respectively. DOX distribution was assessed by immunofluorescence. In the antitumor study, tumor-bearing rabbits received transarterial infusions of lipiodol with DOX, DZCNs, R-DZCNs, or saline respectively. Tumor volume was measured using magnetic resonance imaging, and the expression of apoptosis-related factors (caspase-3, Bax, Bcl-2) was analyzed by immunohistochemistry and Western blotting. RESULTS: R-DZCNs increased cellular uptake and caused stronger cytotoxicity. Compared with the DOX + lipiodol or DZCNs + lipiodol group, the R-DZCNs + lipiodol group showed more DOX fluorescence spots (2,449.15 ± 444.14 vs. 3,464.73 ± 632.75 or 5,062.25 ± 585.62, respectively; P < .001) and longer penetration distance (117.58 ± 19.36 vs 52.64 ± 8.53 or 83.37 ± 13.76 µm, respectively; P < .001). In the antitumor study, the R-DZCNs + lipiodol group showed smaller tumor volumes than the DOX + lipiodol or DZCNs + lipiodol group (1,223.87 ± 223.58 vs. 3,695.26 ± 666.25 or 2281.06 ± 457.21 mm3, respectively; P = .005).The greatest extent of tumor cell apoptosis was observed in R-DZCNs + lipiodol group immunohistochemistry and Western blotting results. CONCLUSIONS: Transarterial infusion of R-DZCNs with lipiodol improved the distribution of DOX and enhanced its antitumor efficacy.

Tumor-Microenvironment-Induced All-in-One Nanoplatform for Multimodal Imaging-Guided Chemical and Photothermal Therapy of Cancer.

Precisely locating tumor site based on tumor-microenvironment-induced (TMI) multimodal imaging is especially interesting for accurate and efficient cancer therapy. In the present investigation, a novel TMI all-in-one nanoplatform, CuSNC@DOX@MnO2-NS, has been successfully fabricated for chemical and photothermal (Chem-PTT) therapy guided by multimodal imaging on tumor site. Here, the CuS nanocages with mesoporous and hollow structure (CuSNC) acting as nanocarriers provide high capacity for loading the anticancer drug, doxorubicin (DOX). The outer layer of the MnO2 nanoshell (MnO2-NS) acts as "gatekeeper" to control the DOX release until the nanoplatform arrives at the tumor site, where abundant glutathione and H+ decompose MnO2-NS into paramagnetic Mn2+. The magnetic resonance imaging and fluorescent imaging were then triggered to locate the tumor, which was further improved by photothermal imaging on account of the intrinsic property of CuSNC. Guided by the multimode imaging, the combination of chemical therapy upon DOX and photothermal therapy upon CuSNC exhibits eminent efficiency on tumor ablation. The nanoplatform exhibits biocompatibility to avoid unwanted harm to normal tissues during trans-shipment in the body. The investigation thus develops a cost-effective TMI nanoplatform with facile preparations and easy integration of Chem-PTT treatment capabilities guided by multimodal imaging for potential application in precise therapy.

Iron-Oxide Nanocluster Labeling of Clostridium novyi-NT Spores for MR Imaging-Monitored Locoregional Delivery to Liver Tumors in Rat and Rabbit Models.

PURPOSE: To label Clostridium novyi-NT spores (C. novyi-NT) with iron oxide nanoclusters and track distribution of bacteria during magnetic resonance (MR) imaging-monitored locoregional delivery to liver tumors using intratumoral injection or intra-arterial transcatheter infusion. MATERIALS AND METHODS: Vegetative state C. novyi-NT were labeled with iron oxide particles followed by induction of sporulation. Labeling was confirmed with fluorescence microscopy and transmission electron microscopy (TEM). T2 and T2* relaxation times for magnetic clusters and magnetic microspheres were determined using 7T and 1.5T MR imaging scanners. In vitro assays compared labeled bacteria viability and oncolytic potential to unlabeled controls. Labeled spores were either directly injected into N1-S1 rodent liver tumors (n = 24) or selectively infused via the hepatic artery in rabbits with VX2 liver tumors (n = 3). Hematoxylin-eosin, Prussian blue, and gram staining were performed. Statistical comparison methods included paired t-test and ANOVA. RESULTS: Both fluorescence microscopy and TEM studies confirmed presence of iron oxide labels within the bacterial spores. Phantom studies demonstrated that the synthesized nanoclusters produce R2 relaxivities comparable to clinical agents. Labeling had no significant impact on overall growth or oncolytic properties (P >.05). Tumor signal-to-noise ratio (SNR) decreased significantly following intratumoral injection and intra-arterial infusion of labeled spores (P <.05). Prussian blue and gram staining confirmed spore delivery. CONCLUSIONS: C. novyi-NT spores can be internally labeled with iron oxide nanoparticles to visualize distribution with MR imaging during locoregional bacteriolytic therapy involving direct injection or intra-arterial transcatheter infusion.

Preparation of a one-dimensional nanorod/metal organic framework Janus nanoplatform via side-specific growth for synergistic cancer therapy.

Janus nanoparticles (JNPs) have emerged in recent years as new compartmentalized colloids with two sides of different components, chemical properties or morphologies that have opened up a wide range of unique applications in biomedicine. Here, we explored a unique lactobionic acid (LA) modified metallic one-dimensional nanorod/metal organic framework (1D NR/MOF) JNP, the LA-gold NR/zeolitic imidazolate framework-8 (LA-AuNR/ZIF-8) JNP, for computed X-ray tomography (CT) image-guided liver cancer targeted synergistic chemo-photothermal theranostics. Taking advantage of the 1D nanostructure of the AuNRs, polyacrilic acid (PAA) was selectively attached to one side of the AuNRs for further growth of ZIF-8, and the exposed side of the AuNRs was modified with the targeting agent LA, thus realizing the drug loading and cancer specific targeting. In addition, the high contrast of Au makes the LA-AuNR/ZIF-8 JNPs suitable for CT image-guided cancer therapy. Furthermore, mice treated with doxorubicin (DOX) loaded LA-AuNR/ZIF-8 JNPs under near infrared (NIR) laser irradiation showed significant tumor inhibition, indicating the effective combination of pH and NIR stimuli response release, cancer specific targeting and synergistic chemotherapy and photothermal therapy.

Chemoembolization with Vascular Disrupting Agent CKD-516 Dissolved in Ethiodized Oil in Combination with Doxorubicin: A VX2 Tumor Model Study.

PURPOSE: To assess feasibility and efficacy of CKD-516, a vascular disrupting agent, in transarterial chemoembolization in a liver tumor model. MATERIALS AND METHODS: A VX2 carcinoma strain was implanted in rabbit liver (n = 40) and incubated for 2 weeks. After confirmation of tumor growth using computed tomography, transarterial chemoembolization was performed. CKD-516 was dissolved in ethiodized oil, and animals were allocated to 4 treatment groups (n = 10 in each): group A, ethiodized oil; group B, ethiodized oil/CKD-516; group C, ethiodized oil + doxorubicin; group D, ethiodized oil/CKD-516 + doxorubicin. To assess hepatic damage, serum aspartate transaminase and alanine transaminase levels were measured on day 1, 3, and 7 after delivery. To assess tumor necrosis, animals were euthanized on day 7, and explanted tumors were stained with hematoxylin and eosin and a terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling assay. Percentage areas of viable tumors were calculated using digitalized histopathologic specimen images. RESULTS: Tumor viability rates were 47.1% ± 11.4%, 27.5% ± 13.6%, 14.4% ± 12.5%, and 0.7% ± 1.0% in groups A, B, C, and D (P < .001). Liver enzyme levels were elevated after drug delivery but recovered during follow-up. Significant between-group differences were observed on days 1, 3, and 7 (aspartate transaminase and alanine transaminase: P = .0135 and P = .0134, P = .0390 and P = .0084, and P = .8260 and P = .0440). CONCLUSIONS: Treatment with a combination of CKD-516 and conventional transarterial chemoembolization showed therapeutic benefit in a liver tumor model.

Multimodality Molecular Imaging-Guided Tumor Border Delineation and Photothermal Therapy Analysis Based on Graphene Oxide-Conjugated Gold Nanoparticles Chelated with Gd.

Tumor cell complete extinction is a crucial measure to evaluate antitumor efficacy. The difficulties in defining tumor margins and finding satellite metastases are the reason for tumor recurrence. A synergistic method based on multimodality molecular imaging needs to be developed so as to achieve the complete extinction of the tumor cells. In this study, graphene oxide conjugated with gold nanostars and chelated with Gd through 1,4,7,10-tetraazacyclododecane-N,N',N,N'-tetraacetic acid (DOTA) (GO-AuNS-DOTA-Gd) were prepared to target HCC-LM3-fLuc cells and used for therapy. For subcutaneous tumor, multimodality molecular imaging including photoacoustic imaging (PAI) and magnetic resonance imaging (MRI) and the related processing techniques were used to monitor the pharmacokinetics process of GO-AuNS-DOTA-Gd in order to determine the optimal time for treatment. For orthotopic tumor, MRI was used to delineate the tumor location and margin in vivo before treatment. Then handheld photoacoustic imaging system was used to determine the tumor location during the surgery and guided the photothermal therapy. The experiment result based on orthotopic tumor demonstrated that this synergistic method could effectively reduce tumor residual and satellite metastases by 85.71% compared with the routine photothermal method without handheld PAI guidance. These results indicate that this multimodality molecular imaging-guided photothermal therapy method is promising with a good prospect in clinical application.

Dual pH/reduction-responsive hybrid polymeric micelles for targeted chemo-photothermal combination therapy.

The combination of chemotherapy and photothermal therapy in multifunctional nanovesicles has emerged as a promising strategy to improve cancer therapeutic efficacy. Herein, we designed new pH/reduction dual-responsive and folate decorated polymeric micelles (FA Co-PMs) as theranostic nanocarrier to co-encapsulate doxorubicin (DOX) and indocyanine green (ICG) for targeted NIR imaging and chemo-photothermal combination therapy. The Co-PMs exhibited nano-sized structure (∼100 nm) with good monodispersity, high encapsulation efficiency of both ICG and DOX, triggered DOX release in response to acid pH and reduction environment, and excellent temperature conversion with laser irradiation. In vitro cellular uptake study indicated FA Co-PMs achieved significant targeting to BEL-7404 cells via folate receptor-mediated endocytosis, and laser-induced hyperthermia further enhanced drug accumulation into cancer cells. In vivo biodistribution study indicated that FA Co-PMs prolonged drug circulation and enhanced drug accumulation into the tumor via EPR effect and FA targeting. Furthermore, the ICG-based photo-triggered hyperthermia combined with DOX-based chemotherapy synergistically induced the BEL-7404 cell death and apoptosis, and efficiently suppressed the BEL-7404 xenografted tumor growth while significantly reduced systemic toxicity in vivo. Therefore, the designed dual-responsive Co-PMs were promising theranostic nanocarriers for versatile antitumor drug delivery and imaging-guided cancer chemo-photothermal combination therapy. STATEMENT OF SIGNIFICANCE: The combination of chemotherapy and photothermal therapy in multifunctional nanovesicles has emerged as a promising strategy to improve cancer therapeutic efficacy. Herein, we designed novel pH/reduction dual-responsive and folate decorated polymeric micelles (FA Co-PMs) as theranostic nanocarrier to co-encapsulate doxorubicin (DOX) and indocyanine green (ICG) for targeted NIR imaging and chemo-photothermal combination therapy. The Co-PMs triggered DOX release in response to acid pH and reduction environment and exhibited excellent temperature conversion with laser irradiation. The results indicated FA Co-PMs achieved significant targeting to BEL-7404 cells in vitro and efficiently suppressed the BEL-7404 xenografted tumor growth while significantly reduced systemic toxicity in vivo. Therefore, the designed dual-responsive Co-PMs displayed great potential in imaging-guided cancer chemo-photothermal combination therapy as theranostic nanocarriers.

Non-invasive monitoring of the therapeutic response in sorafenib-treated hepatocellular carcinoma based on photoacoustic imaging.

PURPOSE: We investigated the changes of tissue oxygen saturation (sO2) in sorafenib-treated HCC (hepatocelluar carcinoma) mouse models using photoacoustic imaging (PI). MATERIALS AND METHODS: Nude mice, implanted with human HCC (HepG2-RFP) cells in the liver, were randomised to the sorafenib-treated group (n = 21) or the control group (n = 20). Tumour volume and sO2 were measured by PI at baseline and then one week later, and radiant efficiency (RE) and therapeutic response were analysed by fluorescence imaging and histologic analysis. RESULTS: Sorafenib was effective in treating HCC by evaluating necrotic fraction, apoptosis index, and microvessel density (MVD). One week after treatment, the sO2 of HCC and residual healthy liver tissue decreased, and the hypoxia inducible factor-1α (HIF-1α) protein expression of HCC increased, correlating with the apoptosis index. The ΔsO2 in HCC showed a significantly positive correlation with the necrotic fraction and the apoptosis index of tumour and a negative correlation with the MVD of tumour. CONCLUSION: Sorafenib treatment results in changes of sO2 in HCC and liver parenchyma and induces the accumulation of HIF-1α by hypoxic environment. sO2 as measured by PI, can be a useful marker for non-invasive monitoring of the therapeutic response in orthotopic HCC mouse models. KEY POINTS: • Hypoxia is a characteristic feature of the tumour microenvironment • It is important to monitor sO 2 in HCC during sorafenib treatment • PI is useful for non-invasive monitoring of sO 2 in HCC. • ΔsO 2 in HCC showed a significantly correlation with tumour response.

Intravoxel incoherent motion MRI for monitoring the therapeutic response of hepatocellular carcinoma to sorafenib treatment in mouse xenograft tumor models.

Background With the introduction of targeted therapies, there has been a growing need for non-invasive imaging methods which accurately evaluate therapeutic effects and overcome the limitations of tumor size-based therapeutic response assessments. Purpose To assess diagnostic values of intra-voxel incoherent motion (IVIM) imaging in evaluating therapeutic effects of sorafenib on hepatocellular carcinoma (HCC) using mouse xenograft model. Material and Methods Twenty-four mice bearing Huh-7 were divided into a control group and two treatment groups received sorafenib doses of 5 mg/kg (5 mg-Tx) or 30 mg/kg (30 mg-Tx). IVIM imaging was performed using 10 b-values (0-900 s/mm2). The apparent diffusion coefficient (ADC), diffusion coefficient ( D), and perfusion fraction ( f) were measured for whole tumors and tumor periphery. Changes between baseline and post-treatment parameters ( Δ ADC, Δ D, and Δ f) were calculated, and these parameters were compared with microvessel density (MVD) and area of tumor cell death. Results The post-treatment f and Δ f for tumor periphery were significantly higher in control group, followed by 5 mg-Tx and 30 mg-Tx ( P < 0.001). MVD showed significant positive correlation with post-treatment f ( r = 0.584, P = 0.003) and negative correlation with D ( r = -0.495, P = 0.014) for tumor periphery, while no parameter showed significant correlation with area of tumor cell death. Conclusion The f is significantly correlated with MVD of HCC, and could potentially be used to evaluate the anti-angiogenic effects of sorafenib.

Microwave coagulation/ablation in combination with sorafenib suppresses the overgrowth of residual tumor in VX2 liver tumor model.

OBJECTIVES: Our study is to evaluate the effect of thermal ablation on residual VX2 tumor tissue and the efficiency of sorafenib as an adjuvant therapy after insufficient microwave coagulation (MWC) on a rabbit VX2 liver tumor model. METHODS: Thirty-seven rabbits with orthotic VX2 liver tumors were randomly divided into MWC group (n=11), combination treatment group (n=14), and control group (n=12). The therapeutic efficacy was evaluated by contrast enhanced ultrasound (CEUS), magnetic resonance imaging (MRI), pathological and immunohistochemical examinations. Analysis of enhancement characteristics included enhancement level, pattern, and location. The necrotic degree of tumor was analyzed by semi-quantitative classification. The apparent diffusion coefficiency (ADC) was calculated using diffused weighted image (DWI). RESULTS: The tumor growth was accelerated in MWC group compared with control group and combination treatment group. A low metastasis rate was shown in combination treatment group compared with other two groups. The degree of necrosis in combination treatment group was greater than that in MWC group. The ADC value on DWI was higher compared with that of the control and MWC group, with statistical significance (P<0.05). With adjuvant therapy of sorafenib after insufficient ablation, the microvessel density (MVD) was lower than that of control group, whereas in MWC group the MVD was higher than that of control group, with statistical significance (P<0.05). CONCLUSION: Insufficient thermal ablation promotes residual tumor progression. While the adjuvant therapy of sorafenib serves as an effective way to suppress the overgrowth and neovascularization of residual tumor after insufficient thermal ablation.

Sorafenib and gadolinium co-loaded liposomes for drug delivery and MRI-guided HCC treatment.

To improve the poor water solubility of sorafenib and to monitor its distribution and the early feedback effects on its in vivo treatment efficacy in a precise manner, sorafenib (SF) and gadolinium (Gd) co-loaded liposomes (SF/Gd-liposomes) were prepared. The simultaneous imaging and therapy efficacies of the SF/Gd-liposomes were tested. The solubility of SF in SF/Gd-liposomes was significantly increased from 0.21 µg/mL to 250 µg/mL. The imaging capability of SF/Gd-liposomes were tested by in-vitro and the in-vivo imaging ability tests and the results confirmed that SF/Gd-liposomes could be served as an effective contrast agent. The design of SF/Gd-liposomes allowed the MRI-guided in vivo visualization of the delivery and biodistribution of liposome. In the in vivo antitumor studies, SF/Gd-liposomes had better antitumor effects in H22 tumor-bearing mice than SF solution (oral or i.v. administration) (P<0.05). These findings indicated that the SF/Gd-liposomes could be used as the promising nano-carriers for the MRI-guided in vivo visualization of the delivery and HCC treatment.

Preparation of Radiopaque Drug-Eluting Beads for Transcatheter Chemoembolization.

PURPOSE: To develop a simple method to produce radiopaque drug-eluting microspheres (drug-eluting beads [DEBs]) that could be incorporated into the current clinical transcatheter arterial chemoembolization workflow and evaluate their performance in vitro and in vivo. MATERIALS AND METHODS: An ethiodized oil (Lipiodol; Guerbet, Villepinte, France) and ethanol solution was added to a lyophilized 100-300 µm bead before loading with doxorubicin. These radiopaque drug-eluting beads (DEBs; Biocompatibles UK Ltd, Farnham, United Kingdom) were evaluated in vitro for x-ray attenuation, composition, size, drug loading and elution, and correlation between attenuation and doxorubicin concentration. In vivo conspicuity was evaluated in a VX2 tumor model. RESULTS: Lipiodol was loaded into lyophilized beads using two glass syringes and a three-way stopcock. Maximum bead attenuation was achieved within 30 minutes. X-ray attenuation of radiopaque beads increased linearly (21-867 HU) with the amount of beads (0.4-12.5 vol%; R(2) = 0.9989). Doxorubicin loading efficiency and total amount eluted were similar to DC Bead (Biocompatibles UK Ltd); however, the elution rate was slower for radiopaque DEBs (P < .05). Doxorubicin concentration linearly correlated with x-ray attenuation of radiopaque DEBs (R(2) = 0. 99). Radiopaque DEBs were seen in tumor feeding arteries after administration by fluoroscopy, computed tomography, and micro-computed tomography, and their location was confirmed by histology. CONCLUSIONS: A simple, rapid method to produce radiopaque DEBs was developed. These radiopaque DEBs provided sufficient conspicuity to be visualized with x-ray imaging techniques.

Multimodality Imaging of Ethiodized Oil-loaded Radiopaque Microspheres during Transarterial Embolization of Rabbits with VX2 Liver Tumors.

Purpose To assess the visibility of radiopaque microspheres during transarterial embolization (TAE) in the VX2 rabbit liver tumor model by using multimodality imaging, including single-snapshot radiography, cone-beam computed tomography (CT), multidetector CT, and micro-CT. Materials and Methods The study was approved by the institutional animal care and use committee. Fifteen VX2-tumor-bearing rabbits were assigned to three groups depending on the type of embolic agent injected: 70-150-µm radiopaque microspheres in saline (radiopaque microsphere group), 70-150-µm radiopaque microspheres in contrast material (radiopaque microsphere plus contrast material group), and 70-150-µm radiolucent microspheres in contrast material (nonradiopaque microsphere plus contrast material group). Rabbits were imaged with single-snapshot radiography, cone-beam CT, and multidetector CT. Three to 5 weeks after sacrifice, excised livers were imaged with micro-CT and histologic analysis was performed. The visibility of the embolic agent was assessed with all modalities before and after embolization by using a qualitative three-point scale score reading study and a quantitative assessment of the signal-to-noise ratio (SNR) change in various regions of interest, including the tumor and its feeding arteries. The Kruskal-Wallis test was used to compare the rabbit characteristics across groups, and the Wilcoxon signed rank test was used to compare SNR measurements before and after embolization. Results Radiopaque microspheres were qualitatively visualized within tumor feeding arteries and targeted tissue with all imaging modalities (P < .05), and their presence was confirmed with histologic examination. SNRs of radiopaque microsphere deposition increased after TAE on multidetector CT, cone-beam CT, and micro-CT images (P < .05). Similar results were obtained when contrast material was added to radiopaque microspheres, except for additional image attenuation due to tumor enhancement. For the group with nonradiopaque microspheres and contrast material, retained tumoral contrast remained qualitatively visible with all modalities except for micro-CT, which demonstrated soluble contrast material washout over time. Conclusion Radiopaque microspheres were visible with all imaging modalities and helped increase conspicuity of the tumor as well as its feeding arteries after TAE in a rabbit VX2 liver tumor model. (©) RSNA, 2015.

Early prediction of response of sorafenib on hepatocellular carcinoma by CT perfusion imaging: an animal study.

OBJECTIVE: This study evaluated the feasibility of CT perfusion parameters for the early efficacy prediction of sorafenib in the treatment of hepatocellular carcinoma (HCC) in rats. METHODS: CT hepatic perfusion measurements were performed in the livers of 40 rats implanted with rat HCC. The rats in the experimental group (n = 28) were treated by oral gavage with sorafenib (20 mg per day), whereas the rats in the control group (n = 12) were treated by normal saline. Rats were classified into the responder group if the maximum diameter of their tumour had decreased 21 days after treatment, whereas the other rats were classified into the non-responder group. Data were analysed using the Pearson correlation analysis or analysis of variance. RESULTS: CT perfusion was used to depict haemodynamic changes before and after treatment. The arterial liver perfusion was significantly decreased in the responder group on Day 11 after treatment with sorafenib (from 71.5 to 53.4 ml min(-1) 100 ml(-1)), whereas no significant changes were observed in the non-responder group (p = 0.87). The maximum diameter of the tumour was also significantly decreased in the responder group on Day 21 after treatment (p = 0.042), whereas the maximum tumour diameter was significantly increased in the control group (p = 0.001). CONCLUSION AND ADVANCES IN KNOWLEDGE: CT perfusion could be used to quantitatively analyse the haemodynamic changes in the treatment of HCC with sorafenib, which indicates that this approach may be developed for the early prediction of treatment efficacy for sorafenib.

Early prediction of treatment response to sorafenib with elastosonography in a mice xenograft model of hepatocellular carcinoma: a proof-of-concept study.

PURPOSE: Sorafenib is the reference therapy for advanced hepatocellular carcinoma (HCC). There is no method for predicting in the early period subsequent individual response. Starting from the clinical experience in humans that subcutaneous metastases may rapidly change consistency under sorafenib and that elastosonography allows assessment of tissue elasticity, we investigated the role of this ultrasound-based technique in the early prediction of tumor response to sorafenib in a HCC mice model. MATERIALS AND METHODS: HCC subcutaneous xenografting in mice was utilized. Mice were randomized to vehicle (17 mice) or treatment with sorafenib (19 mice). Strain elastosonography (Esaote, Italy) of the tumor mass was performed at different time points (day 0, + 2 and + 14 from treatment start) until the mice were sacrificed (day + 14). At the same time points, the volume was calculated with ultrasonography. RESULTS: Sorafenib-treated mice showed a smaller increase in tumor size on day + 14 in comparison to vehicle-treated mice (tumor volume increase + 175 % vs. + 382 %, p = 0.009). The median tumor elasticity increased in both groups on day + 2 (+ 5.65 % and + 3.86 %, respectively) and decreased on day + 14 (-3.86 % and -3.63 %, respectively). However, among Sorafenib-treated tumors, 13 mice with a growth percentage delta < 200 % (considered as good treatment response) showed an increase in elasticity on day + 2 (+ 8.9 %, range -12.6 - + 64) while the other 6 with a growth percentage delta > 300 % (considered as poor treatment response) showed a decrease in elasticity (-17 %, range -30.2 - + 15.3) (p = 0.044). CONCLUSION: Elastosonography appears to be a promising noninvasive new technique for the early treatment prediction of HCC tumor response to sorafenib. Specifically, an early increase in tumor elasticity (corresponding to tumors becoming softer) is associated with a good response.