Simultaneous Li-Doping and Formation of SnO2-Based Composites with TiO2: Applications for Perovskite Solar Cells.

Tin oxide (SnO2) has been recognized as one of the beneficial components in the electron transport layer (ETL) of lead-halide perovskite solar cells (PSCs) due to its high electron mobility. The SnO2-based thin film serves for electron extraction and transport in the device, induced by light absorption at the perovskite layer. The focus of this paper is on the heat treatment of a nanoaggregate layer of single-nanometer-scale SnO2 particles in combination with another metal-dopant precursor to develop a new process for ETL in PSCs. The combined precursor solution of Li chloride and titanium(IV) isopropoxide (TTIP) was deposited onto the SnO2 layer. We varied the heat treatment conditions of the spin-coated films comprising double layers, i.e., an Li/TTIP precursor layer and SnO2 nanoparticle layer, to understand the effects of nanoparticle interconnection via sintering and the mixing ratio of the Li-dopant on the photovoltaic performance. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) measurements of the sintered nanoparticles suggested that an Li-doped solid solution of SnO2 with a small amount of TiO2 nanoparticles formed via heating. Interestingly, the bandgap of the Li-doped ETL samples was estimated to be 3.45 eV, indicating a narrower bandgap as compared to that of pure SnO2. This observation also supported the formation of an SnO2/TiO2 solid solution in the ETL. The utilization of such a nanoparticulate SnO2 film in combination with an Li/TTIP precursor could offer a new approach as an alternative to conventional SnO2 electron transport layers for optimizing the performance of lead-halide perovskite solar cells.

Growth and Dispersion Control of SnO2 Nanocrystals Employing an Amino Acid Ester Hydrochloride in Solution Synthesis: Microstructures and Photovoltaic Applications.

Tin oxide (SnO2) is a technologically important semiconductor with versatile applications. In particular, attention is being paid to nanostructured SnO2 materials for use as a part of the constituents in perovskite solar cells (PSCs), an emerging renewable energy technology. This is mainly because SnO2 has high electron mobility, making it favorable for use in the electron transport layer (ETL) in these devices, in which SnO2 thin films play a role in extracting electrons from the adjacent light-absorber, i.e., lead halide perovskite compounds. Investigation of SnO2 solution synthesis under diverse reaction conditions is crucial in order to lay the foundation for the cost-effective production of PSCs. This research focuses on the facile catalyst-free synthesis of single-nanometer-scale SnO2 nanocrystals employing an aromatic organic ligand (as the structure-directing agent) and Sn(IV) salt in an aqueous solution. Most notably, the use of an aromatic amino acid ester hydrochloride salt-i.e., phenylalanine methyl ester hydrochloride (denoted as L hereafter)-allowed us to obtain an aqueous precursor solution containing a higher concentration of ligand L, in addition to facilitating the growth of SnO2 nanoparticles as small as 3 nm with a narrow size distribution, which were analyzed by means of high-resolution transmission electron microscopy (HR-TEM). Moreover, the nanoparticles were proved to be crystallized and uniformly dispersed in the reaction mixture. The environmentally benign, ethanol-based SnO2 nanofluids stabilized with the capping agent L for the Sn(IV) ions were also successfully obtained and spin-coated to produce a SnO2 nanoparticle film to serve as an ETL for PSCs. Several SnO2 ETLs that were created by varying the temperature of nanoparticle synthesis were examined to gain insight into the performance of PSCs. It is thought that reaction conditions that utilize high concentrations of ligand L to control the growth and dispersion of SnO2 nanoparticles could serve as useful criteria for designing SnO2 ETLs, since hydrochloride salt L can offer significant potential as a functional compound by controlling the microstructures of individual SnO2 nanoparticles and the self-assembly process to form nanostructured SnO2 thin films.

1D Narrow-Bandgap Tin Oxide Materials: Systematic High-Resolution TEM and Raman Analysis.

We demonstrate for the first time the structure identification and narrow-bandgap property of 1D hybridized SnO/SnO2 nanoparticles derived from the calcination of a single-source precursor, i.e., tin(II) oxalate. Systematic Raman analysis together with high-resolution TEM (HR-TEM) measurements of the tin oxide samples were carried out by changing the calcination temperatures. These data revealed the simultaneous formation of 1D SnO/SnO2 in the rod particles that grew in air. It was also found that Sn(II) can be introduced by changing the concentration of Sn(II) salt in the precursor synthesis and the maximum temperature in calcination. Particles measuring 20~30 nm were sintered to produce tin oxide nanorods including tin monoxide, SnO. Photoabsorption properties associated with the formation of the SnO/SnO2 nanocomposites were also investigated. Tauc plots indicate that the obtained tin oxide samples had a lower bandgap of 2.9~3.0 eV originating from SnO in addition to a higher bandgap of around 3.5~3.7 eV commonly observed for SnO2. Such 1D SnOx/SnO2 hybrids via tin oxalate synthesis with this optical property would benefit new materials design for photoenergy conversion systems, such as photocatalysts.

Preparation of Nanostructured Sn/Ti Oxide Hybrid Films with Terpineol/PEG-Based Nanofluids: Perovskite Solar Cell Applications.

Tin oxide (SnO2) and titanium dioxide (TiO2) are recognized as attractive energy materials applicable for lead halide perovskite solar cells (PSCs). Sintering is one of the effective strategies for improving the carrier transport of semiconductor nanomaterials. Using the alternative metal-oxide-based ETL, nanoparticles are often used in a way that they are dispersed in a precursor liquid prior to their thin-film deposition. Currently, the creation of PSCs using nanostructured Sn/Ti oxide thin-film ETL is one of the topical issues for the development of high-efficiency PSCs. Here, we demonstrate the preparation of terpineol/PEG-based fluid containing both tin and titanium compounds that can be utilized for the formation of a hybrid Sn/Ti oxide ETL on a conductive substrate (F-doped SnO2 glass substrate: FTO). We also pay attention to the structural analysis of the Sn/Ti metal oxide formation at the nanoscale using a high-resolution transmission electron microscope (HR-TEM). The variation of the nanofluid composition, i.e., the concentration of tin and titanium sources, was examined to obtain a uniform transparent thin film by spin-coating and sintering processes. The maximum power conversion efficiency was obtained for the concentration condition of [SnCl2·2H2O]/[titanium tetraisopropoxide (TTIP)] = 25:75 in the terpineol/PEG-based precursor solution. Our method for preparing the ETL nanomaterials provides useful guidance for the creation of high-performance PSCs using the sintering method.

Organically surface engineered mesoporous silica nanoparticles control the release of quercetin by pH stimuli.

Controlling the premature release of hydrophobic drugs like quercetin over physiological conditions remains a challenge motivating the development of smart and responsive drug carriers in recent years. This present work reported a surface modification of mesoporous silica nanoparticles (MSN) by a functional compound having both amines (as a positively charged group) and carboxylic (negatively charged group), namely 4-((2-aminoethyl)amino)-4-oxobut-2-enoic acid (AmEA) prepared via simple mechanochemistry approach. The impact of MSN surface modification on physical, textural, and morphological features was evaluated by TGA, N2 adsorption-desorption, PSA-zeta, SEM, and TEM. The BET surface area of AmEA-modified MSN (MSN-AmEA) was found to be 858.41 m2 g-1 with a pore size of 2.69 nm which could accommodate a high concentration of quercetin 118% higher than MSN. In addition, the colloidal stability of MSN-AmEA was greatly improved as indicated by high zeta potential especially at pH 4 compared to MSN. In contrast to MSN, MSN-AmEA has better in controlling quercetin release triggered by pH, thanks to the presence of the functional groups that have a pose-sensitive interaction hence it may fully control the quercetin release, as elaborated by the DFT study. Therefore, the controlled release of quercetin over MSN-AmEA verified its capability of acting as a smart drug delivery system.

Manufacturing a TiO2-Based Semiconductor Film with Nanofluid Pool Boiling and Sintering Processes toward Solar-Cell Applications.

For the first time, nanofluid boiling was applied as a process for the creation of a semiconductor TiO2 nanoparticle film that can be deposited onto a conductive substrate (F-doped SnO2 glass: FTO). A steel-base device designed for pool boiling was used to deposit a TiO2-based nanofluid consisting of nanoparticles with an average size of about 20 nm. The boiling of the nanofluid directly on the FTO glass substrate allowed for the deposition of the nanoparticles onto the FTO surface. In principle, the surface responsible for transferring heat to the fluid can be covered with these nanoparticles when the nanofluid boils. Using the as-deposited films, crystal growth of the TiO2 nanoparticle was controlled by varying the strategies of the post-sintering profile. The maximum temperatures, periods, and ramping rates for the obtained samples were systematically changed. Scanning electron microscopy (SEM) revealed that a densely packed TiO2-nanoparticle layer was obtained for the as-deposited substrate via pool boiling. For the maximum temperature at 550 °C, the TiO2 grain sizes became larger (~50 nm) and more round-shaped TiO2 nanostructures were identified. Notably, we have demonstrated for the first time how the sintering of TiO2 nanoparticles proceeds for the nanoporous TiO2 films using high-resolution transmission electron microscopy (TEM) measurements. We found that the TiO2 nanoparticles fused with each other and crystal growth occurred through neighboring 2-4 nanoparticles for the 550 °C sample, which was proved by the TEM analysis that continuous lattice fringes corresponding to the (101) anatase phase were clearly observed through the entire area of some nanoparticles aligned horizontally. In addition, the loss of the TiO2 nanofluid (precursor solution) was completely avoided in our TiO2 deposition. Unlike the commonly used spin-coating method, nanofluid pool boiling would provide an alternative cost-effective approach to manufacture semiconductor layers for various applications, such as solar cells.

Elucidation of the Crystal Growth Characteristics of SnO2 Nanoaggregates Formed by Sequential Low-Temperature Sol-Gel Reaction and Freeze Drying.

SnO2 nanoparticles are regarded as attractive, functional materials because of their versatile applications. SnO2 nanoaggregates with single-nanometer-scale lumpy surfaces provide opportunities to enhance hetero-material interfacial areas, leading to the performance improvement of materials and devices. For the first time, we demonstrate that SnO2 nanoaggregates with oxygen vacancies can be produced by a simple, low-temperature sol-gel approach combined with freeze-drying. We characterize the initiation of the low-temperature crystal growth of the obtained SnO2 nanoaggregates using high-resolution transmission electron microscopy (HRTEM). The results indicate that Sn (II) hydroxide precursors are converted into submicrometer-scale nanoaggregates consisting of uniform SnO2 spherical nanocrystals (2~5 nm in size). As the sol-gel reaction time increases, further crystallization is observed through the neighboring particles in a confined part of the aggregates, while the specific surface areas of the SnO2 samples increase concomitantly. In addition, X-ray photoelectron spectroscopy (XPS) measurements suggest that Sn (II) ions exist in the SnO2 samples when the reactions are stopped after a short time or when a relatively high concentration of Sn (II) is involved in the corresponding sol-gel reactions. Understanding this low-temperature growth of 3D SnO2 will provide new avenues for developing and producing high-performance, photofunctional nanomaterials via a cost-effective and scalable method.

A molten salt-based nitridation approach for synthesizing nanostructured InN electrode materials.

Single-phase InN nanocrystals were synthesized for the first time by a molten salt-based nitridation approach using InCl3 and LiNH2 as indium and nitrogen sources, respectively. A molten salt, KCl-LiCl, during nitridation, enabled us to obtain InN nanocrystals at relatively low temperatures ranging from 400 °C to 500 °C. SEM and HR-TEM measurements coupled with XRD data revealed that InN nanocrystals were formed with average grain sizes of approximately 50-60 nm. Notably, the photoelectrochemical cell fabricated using the InN nanocrystals synthesized at 450 °C exhibited a photocurrent response under light irradiation from 400 nm to 880 nm. The precise control of the growth of InN particles using our synthetic approach provides opportunities for developing versatile nitride nanocrystals.

Efficacy and Safety of Regorafenib or TAS-102 in Patients with Metastatic Colorectal Cancer Refractory to Standard Therapies.

BACKGROUND: Regorafenib and TAS-102 are novel antitumor agents for patients with metastatic colorectal cancer (mCRC) whose disease has progressed after standard therapies. In randomized trials, regorafenib and TAS-102 prolonged survival in patients with mCRC. However, the appropriate selection of regorafenib or TAS-102 in treatment strategy has not yet been established. PATIENTS AND METHODS: We performed a retrospective analysis, between March 2013 and July 2015, on the efficacy and safety of regorafenib or TAS-102. RESULTS: Thirty-seven patients with mCRC treated with regorafenib or TAS-102 were included. Of these 37 patients, 23 first received regorafenib and 14 received TAS-102. The median progression-free survival and overall survival were 3.0 and 5.8 months, respectively, in the regorafenib group and 2.1 and 6.3 months, respectively, in the TAS-102 group. Drug-related adverse events (AEs) and grade ≥3 AEs were 23 (100%) and 10 (43.5%), respectively, in the regorafenib group and 13 (92.9%) and 2 (14.3%), respectively, in the TAS-102 group. The most frequent grade ≥3 AEs were hepatotoxicity (17.4%) and hand-foot syndrome (13.0%) in the regorafenib group, and neutropenia (14.3%) in the TAS-102 group. In subgroup analysis, the median overall survival was 11.5 months in patients receiving crossover treatment with regorafenib to TAS-102, and 7.6 months in those receiving crossover treatment with TAS-102 to regorafenib. CONCLUSION: Our results showed that regorafenib and TAS-102 have comparable efficacy but different toxicity profiles in patients with mCRC. Both are considered new salvage treatment options. Differences in the toxicity profiles between the two treatments will help in choosing regorafenib or TAS-102.

Electrochemical Self-Assembly of Nanostructured CuSCN/Rhodamine B Hybrid Thin Film and Its Dye-Sensitized Photocathodic Properties.

Nanostructured hybrid thin films of CuSCN and rhodamine B (RB) are electrochemically self-assembled (ESA) by cathodic electrolysis in an ethanol/water mixture containing Cu2+, SCN-, and RB. By selecting the solvent, Cu2+/SCN- ratio, and the concentration of RB, we demonstrate several control parameters in the film formation. High loading of RB into the film has been achieved to reach a CuSCN:RB volume ratio of approximately 2:1. The RB solid could almost completely be extracted from the hybrid film by soaking the film in dimethylacetamide (DMA), leading to a large increase of the surface area. The crystallographic orientation of the nanostructure with respect to the substrate can be controlled. Efficient quenching of fluorescence of RB has been observed for the CuSCN/RB hybrid film, implying hole injection from RB excited state to CuSCN. Photoelectrochemical study on the porous crystalline CuSCN obtained after the DMA treatment and sensitized with RB revealed sensitized photocathodic action under visible light illumination, indicating the potential usefulness of the porous CuSCN electrodes for construction of tandem dye-sensitized solar cells.

Size-controlled synthesis of anisotropic TiO2 single nanocrystals using microwave irradiation and their application for dye-sensitized solar cells.

A microwave hydrothermal reaction of colloidal titanates is presented as a cost-effective synthesis to produce TiO(2) single nanocrystals. The photoelectrode consisting of anisotropic nanorods and V-shaped twins has a significant advantage for achieving an appreciable incident photon-to-current conversion efficiency of 85.6% for the dye-sensitized solar cell.

[A recurrent gastric cancer patient with multiple organ metastasis who achieved partial remission by multidisciplinary therapy (radiochemotherapy plus hyperthermia)].

A 77-year-old male patient visited our hospital for postoperative gastric cancer in September of 2007. He suffered from serious appetite loss, general fatigue, nausea and some other side effects since he was taking S-1(100 mg/day) for the postoperative adjuvant therapy. Chest enhanced CT(as of September, 2007)revealed right mediastinum lymph node metastases and multiple liver metastases that had been diagnosed at the operation were evaluated as remission. He re-started S-1 with a lower dose(80 mg/day)soon after he visited our hospital as an outpatient. That side-effect was slightly improved. However, PET-CT(as of May, 2008)showed another metastasis of left supraclavicular lymph nodes(Virchow lymph nodes). Multidisciplinary therapy, chemotherapy(docetaxel 60 mg/m2, every 3 weeks), radiotherapy and hyperthermia were performed and PET-CT(as of July, 2008)showed left supraclavicular lymph node metastases were evaluated as complete remission, and as to right mediastinum lymph node metastases, we achieved partial remission. Thus, overall partial remission was achieved with the RECIST guideline.

[Efficacy of 5-FU hepatic arterial infusion with l-leucovorin for patients with unresectable colorectal liver metastasis].

We investigated the efficacy of 5-FU hepatic artery infusion (HAI)for patients with unresectable colorectal liver metastasis. Fifteen patients who received HAI between June 2004 and December 2006 were studied. HAI was attempted as first-line chemotherapy in seven patients(Group A)and as second-line or more in eight(Group B). The response rate, time to progression, survival and toxicity were compared with those of 39 patients treated with systemic chemotherapy(18 as first-line: Group C, 21 as second-line or more: Group D). Response rate was 85.7%, 35.7%, 50.0%, and 4.8% in Groups A, B, C, and D, respectively. Time to progression was 12.5 months, 4.7 months, 5.8 months, and 2.3 months, in Groups A, B, C, and D, respectively, and significantly longer in Group A compared with Group C, as well as in Group B compared with Group D. Median survival was 15.4 months, 9.1 months, 11.3 months, and 8.0 months in Groups A, B, C, and D, respectively, and significantly longer in Group B compared with Group D. Grade 3 or 4 non-hematological toxicity was not observed in Group A and B. HAI was effective for the control of unresectable colorectal liver metastasis and improved survival as second-line chemotherapy or more.

Bland embolization of hepatocellular carcinoma using superabsorbent polymer microspheres.

The purpose of this study was to investigate the clinical outcomes of bland embolization using superabsorbent polymer microspheres (SAP-TAE) as an initial therapeutic option for previously untreated hepatocellular carcinoma (HCC) ineligible for resection or ablation. Fifty-nine patients with previously untreated HCC unamenable to surgery or ablation underwent bland embolization using 100- to 200-mum reconstituted SAP particles (SAP-TAE) as the initial treatment. SAP-TAE was repeated as needed based on tumor response but was switched to chemoembolization when necessary to control residual or progressive tumor. Early tumor response was assessed by contrast-enhanced CT according to RECIST and EASL criteria 1 month after the initial SAP-TAE. The overall survival was calculated using the Kaplan-Meier method. The overall mean follow-up period was 30.6 months (range, 7-59 months). A total of 121 sessions of SAP-TAE were performed, with 1-5 sessions per patient (mean, 2.1 sessions). The mean period of repeated SAP-TAE was 15.6 months (range, 1-51 months), and it exceeded 1 and 2 years in 32 (54%) and 15 (25%) patients, respectively. Thirteen (22%) patients underwent repeated SAP-TAE alone, and the remaining 46 (78%) patients underwent subsequent chemoembolization. No major complication was observed and postembolization syndrome was minimal after SAP-TAE in all patients. Response rate was 14% and 66% by RECIST and EASL criteria, respectively. Overall survival rates were 100% and 83% at 1 and 2 years, respectively, and median survival time was 30 months. In conclusion, SAP-TAE was a safe and repeatable option as the induction therapy for HCC unamenable to surgery or ablation, despite the high incidence of converting to TACE during the total course.

[An icteric type hepatocellular carcinoma with no detectable tumor in the liver but with an intrabile duct recurrent tumor].

A 70-year-old man was admitted to our hospital with obstructive jaundice. We performed a laparotomy. The intraductal tumor was removed with the extrahepatic bile ducts. A histological examination of the tumor showed an icteric type hepatocellular carcinoma. The recurrent tumor was detected as intrajejunal tumor thrombi by a CT scan. No lesions were detected in the liver by a CT scan, ultrasonography, and angiography. We performed the second laparotomy. The tumor thrombi in jejunal limb were removed. At 2 months after the operation, an intrahepatic lesion and tumor thrombi were detected. TACE were performed two times and the response was CR. At 16 months after the operation, no recurrence has been seen in this patient.

[A case of postoperative liver metastasis from bile duct carcinoma responding to transarterial chemoembolization].

A 77-year-old man underwent pylorus-preserving pancreatoduodenectomy for bile duct carcinoma in October 2000. Histological diagnosis was moderately-differentiated tubular adenocarcinoma, pT 2 (ss, pHinf 0, pPanc 1, pPV 0, pA 0), pN 0, and final Stage II. The patient was periodically observed after operation. In September 2003, follow-up abdominal CT examinations revealed a liver tumor, 89 x 62 x 60 mm in size, at the anterior segment. Transarterial chemoembolization with 5-FU, epirubicin, mitomycin C and superabsorbent polymer microsphere was initiated under the diagnosis of liver metastasis. After completion of 4 chemoembolizations, the tumor responded partially and diminished to 50 x 16 x 14 mm in CT and superparamagnetic iron oxide-enhanced MRI. Currently, the patient is free from any signs of relapse.

[A case of advanced hepatocellular carcinoma with tumor thrombus treated by transarterial chemoembolization therapy using cisplatin (CDDP) with DSM and SAP-MS].

A 78-year-old woman with advanced HCC had been treated by transarterial chemoembolization with epirubicin, however, tumor progression was not controlled and a tumor thrombus was found in the portal vein trunk. A new treatment method for transarterial chemoembolization using CDDP with DSM and SAP-MS was introduced. Marked regression of hepatic lesions and portal vein tumor thrombus was observed after two sessions. No adverse effect was found. The patient has been controlled without tumor recurrence and elevation of tumor marker for 14 months. A new treatment protocol will be useful for patients with far advanced hepatocellular carcinoma with portal vein tumor thrombus.

Balloon-occluded retrograde transvenous obliteration performed in a pediatric patient with isolated gastric fundal varices.

BACKGROUND: For giant gastric varices in association with portal hypertension, endoscopic treatment often is difficult. Although balloon-occluded retrograde transvenous obliteration (B-RTO) has been performed successfully in adult cirrhotic patients, there has been no report in pediatric patients. METHODS: A 10-year-old girl with biliary atresia (BA) who had been free of jaundice after hepatic portoenterostomy was detected to have isolated gastric fundal varices by routine endoscopy. They gradually enlarged up to 4 cm in diameter, showing a tense appearance, so prophylactic treatment was conducted. Magnetic resonance angiography showed the blood flow of the varices mainly drained by a large gastrorenal shunt. A balloon catheter was introduced into the gastrorenal shunt via the femoral vein and was inflated to occlude the outflow of the varices. Five percent ethanolamine oleate was injected into the varices, and the outflow occlusion was kept for more than 30 minutes. Extensive thrombosis was achieved by an additional embolotherapy after 17 months. Throughout the course, the patient has been doing well without bleeding or worsening of the liver function tests. CONCLUSIONS: B-RTO for isolated gastric fundal varices has been performed safely in a pediatric patient and seems effective in reducing the variceal size and tension.

Using superparamagnetic iron oxide-enhanced MRI to differentiate metastatic hepatic tumors and nonsolid benign lesions.

OBJECTIVE: We evaluated the ability of superparamagnetic iron oxide (SPIO)-enhanced MRI to differentiate solid metastatic tumors and nonsolid benign lesions by clarifying the characteristic signal-intensity pattern of each lesion on SPIO-enhanced T2-weighted and heavily T1-weighted gradient-echo images. MATERIALS AND METHODS: SPIO-enhanced MRI was performed using a 1.5-T system in 33 consecutive patients without cirrhosis who had 81 focal hepatic lesions (42 cysts, 13 hemangiomas, 26 metastatic tumors). The relative signal intensity of lesions on SPIO-enhanced heavily T1- and T2-weighted gradient-echo images was classified into one of the following three categories: high intensity, isointensity, or low intensity relative to the surrounding liver parenchyma. The diagnostic accuracy for differentiating solid metastatic tumors from nonsolid benign lesions (cysts or hemangiomas) was determined. RESULTS: A combination of the relative signal intensity of the lesion on T2- and heavily T1-weighted gradient-echo images could be classified into the following five categories: high intensity and high intensity (category 1), high intensity and isointensity (category 2), high intensity and low intensity (category 3), isointensity and isointensity (category 4), and isointensity and low intensity (category 5). According to these categories, category 1 contained two hemangiomas, category 2 had 11 hemangiomas, category 3 had 25 metastatic tumors and two cysts, category 4 had three cysts, and category 5 had 37 cysts and one metastatic tumor. When a tumor with a relative signal intensity of categories 1 or 2 was considered to be a hemangioma (category 3 metastatic tumors and categories 4 and 5 cysts), diagnostic accuracy for characterizing such hepatic lesions was 96% (78/81). CONCLUSION: When evaluating metastatic liver tumors on SPIO-enhanced MRI, we recommend that heavily T1- and T2-weighted gradient-echo images be obtained with our parameters to exclude hemangiomas or cysts.

Detection of hepatocellular carcinoma: comparison of dynamic MR imaging with dynamic double arterial phase helical CT.

OBJECTIVE: Three-dimensional (3D) Fourier transformation-enhanced fast gradient-echo sequences with a special spectral inversion recovery pulse and fat suppression developed for abdominal imaging, including MR angiography, can show enhanced areas clearly. The purpose of this study was to evaluate the efficacy of dynamic MR imaging with the pulse sequences for the detection of hypervascular hepatocellular carcinoma by comparing it with that of dynamic helical CT with double arterial phase imaging. SUBJECTS AND METHODS: Fifty-three patients with 103 hypervascular hepatocellular carcinoma nodules who underwent both dynamic MR imaging with 3D Fourier transformation-enhanced fast gradient-echo sequences with a special spectral inversion recovery pulse and dynamic helical CT with double arterial phase imaging were enrolled in the study. For dynamic MR imaging, unenhanced, arterial, portal venous, and equilibrium phase images were obtained before and approximately 19, 60, and 120 sec, respectively, after injection of gadopentetate dimeglumine. Three observers independently interpreted the images obtained with each technique in a blinded manner and in random order. RESULTS: Mean sensitivity and positive predictive values of CT for hypervascular hepatocellular carcinoma (66% and 97%, respectively) were higher than those of MR imaging (63% and 96%, respectively), but there was no significant difference in detecting sensitivity among the observers (p < 0.05). CT and MR imaging were complementary, with some tumors undetected by CT but revealed on MR imaging. There was also no significant difference in A(z) values between CT (0.74) and MR imaging (0.71) (p < 0.05). CONCLUSION: Dynamic MR imaging with 3D Fourier transformation-enhanced fast gradient-echo sequences with a special spectral inversion recovery pulse is recommended to improve the detection of hypervascular hepatocellular carcinoma nodules in addition to the use of dynamic helical CT with double arterial phase imaging.