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PURPOSE We assessed what MR imaging parameters affected ringing artifacts during the arterial phase of gadoxetic acid-enhanced dynamic magnetic resonance (MR) imaging. MATERIALS AND METHODS We tested various parameters, including imaging matrices, choice of either sequential or elliptical centric phase-encoding scheme, scanning time, and contrast injection rate using new simulation software on a personal computer and visually evaluated clinical MR images retrospectively using a 4-point scale to assess ringing artifacts. RESULTS The simulation study revealed that square matrices, short scanning time, slow injection rate, and sequential view ordering effectively reduced ringing artifacts, findings confirmed in clinical practice using gadoxetic acid-enhanced MR imaging. Significantly fewer artifacts resulted using a slow injection rate (P

The purpose of this study was to evaluate whether experimental fine-cell detector computed tomography with a 0.3125 mm cell (0.3 mm cell CT) can improve the detection of coronary vessel walls compared with conventional 64-slice computed tomography with a 0.625 mm cell (0.6 mm cell CT). A coronary vessel wall phantom was scanned using 0.6 mm cell CT and 0.3 mm cell CT. The data for 0.3 mm cell CT were obtained using four protocols: a radiation dose equal, double, triple or quadruple that were used in the 0.6 mm cell CT protocol. The detectable size of the vessel wall was assessed based on the first and second derivative functions, and the minimum measurable values were compared using a paired t-test. As a result, the minimum detectable wall thickness of 0.6 mm cell CT (1.5 mm) was significantly larger than that of 0.3 mm cell CT performed using the triple- and quadruple-dose protocols (0.9 mm) and the double-dose protocol (1.1 mm). The difference in the minimum detectable vessel wall thickness measured using 0.6 mm cell CT (1.5 ± 0.1 mm) and 0.3 mm cell CT (0.9 ± 0.1 mm, 1.1 ± 0.2 mm) was significant (p < 0.01). We concluded that 0.3 mm cell CT improved the detection of coronary vessel walls when a more than double-dose protocol was used compared with 0.6 mm cell CT.

To compare image quality obtained in phantoms with virtual monochromatic spectral (VMS) imaging with that obtained with conventional 120-kVp computed tomography (CT) for a given radiation dose.Three syringes were filled with a diluted contrast medium (each syringe contained a contrast medium with a different iodine concentration [5, 10, or 15 mg of iodine per milliliter]), and a fourth syringe was filled with water. These syringes were placed in a torso phantom meant to simulate the standard human physique. The phantom was examined with a CT system and use of the fast kilovoltage switching (80 and 140 kVp) and conventional (120 kVp) modes. Image noise and contrast-to-noise (CNR) ratio were analyzed on VMS images and 120-kVp CT images.Image noise on VMS images in the range of 67-72 keV was significantly lower than that on the 120-kVp CT images (P.014). Image noise was lowest at 69 keV and was 12% lower when compared with that on 120-kVp CT images. CNR on the VMS images was highest at 68 keV. CNR on the VMS images obtained at 68 keV in the syringes filled with diluted contrast material (5, 10, and 15 mg of iodine per milliliter) was 28%, 31%, and 30% higher, respectively, compared with that on the 120-kVp CT images (P.001).VMS imaging at approximately 70 keV yielded lower image noise and higher CNR than did 120-kVp CT for a given radiation dose. VMS imaging has the potential to replace 120-kVp CT as the standard CT imaging modality, since optimal VMS imaging may be expected to yield improved image quality in a patient with standard body habitus.

As an epoxy-based negative photoresist, SU-8 is being widely used for various permanent use MEMS devices due to its excellent thermal and chemical stability. Due to its UV curability, classical structuring methods of SU-8 are based on UV photolithography and UV imprint processes. This study describes a process to form a micro pattern in SU-8 film that is based on thermal imprinting. One of major obstacles in the process is that SU-8 is easy to deform during and after releasing a mold because the mold is separated from the SU-8 in the un-cured state. In this study, series of imprint tests using a Ni mold were performed with the un-cured SU-8 samples pre-treated with UV light for different exposure time, and their results were compared each other in terms of the replication quality. As a result, a SU-8 sample pre-treated with UV light for 8 s resulted in the best replication quality for given imprint conditions, and we could successfully replicate micro patterns with the aspect ratio of 2.5 (25 mum depth and 10 mum line-and-spacing) in SU-8 resist.

The issue of integrating copper with low-dielectric constant (low-k) films for interconnects has been greatly alleviated due to the size reduction of integrated circuits (ICs). This study describes a process for copper micro patterning in parylene-C thin film that combines the hot-embossing and electroplating techniques. The process begins with the deposition of a parylene film on a silicon wafer by a vapor deposition polymerization method. To improve the adhesion of a parylene-C onto a silicon, a silicon wafer was treated using SF6 plasma for 2 min, and spin-coated with an adhesion promoter before parylene deposition. Then, the surfaces of parylene-C films were embossed and subsequently treated by O2 plasma at 2 min to improve the adhesion between the parylene and the Cu/Ta seed layer. Finally, micro-scale gap-filled copper lines with the aspect ratio of 2.5 were electroplated, and the back side of electroplated metal is planarized to the level of the top of the parylene-C layer by a chemical mechanical planarization (CMP) process.

We report two cases of cystic neoplasm of the liver with mucinous epithelium in which both ovarian-like stroma and bile duct communication were absent. The first case was a 41-year-old woman. She underwent right trisegmentectomy due to a multilocular cystic lesion, 15 cm in diameter, with papillary nodular components in the medial segment and right lobe. Histologically, arborizing papillae were seen in the papillary lesion. The constituent neoplastic cells had sufficient cytoarchitectural atypia to be classified as high-grade dysplasia. The second case was a 60-year-old woman. She underwent left lobectomy due to a unilocular cystic lesion, 17 cm in diameter, in the left lobe. Histologically, the cyst wall was lined by low columnar epithelia with slight cellular atypia. In both cases, neither ovarian-like stroma nor bile duct communications were found throughout the resected specimen. According to the most recent World Health Organization (WHO) classification in 2010, cystic tumors of the liver with mucinous epithelium are classified as mucinous cystic neoplasms when ovarian-like stromata are found, and as intraductal papillary neoplasm of bile duct when bile duct communication exists. Therefore, we diagnosed the cystic tumors as ‘biliary cystadenoma’ according to the past WHO classification scheme from 2000. We believe that the combined absence of both ovarian-like stroma and bile duct communication is possible in mucinous cystic tumors of the liver. Herein, we have described the clinicopathologic features of the two cases and reviewed past cases in the literature.

We report a case of concomitant pancreatic endocrine neoplasm (PEN) and intraductal papillary mucinous neoplasm (IPMN). A 74-year-old man had been followed-up for mixed-type IPMN for 10 years. Recent magnetic resonance images revealed an increase in size of the branch duct IPMN in the pancreas head, while the dilation of the main pancreatic duct showed minimal change. Although contrast-enhanced computed tomography and magnetic resonance imaging did not reveal any nodules in the branch duct IPMN, endoscopic ultrasound indicated a suspected nodule in the IPMN. A malignancy in the branch duct IPMN was suspected and we performed pylorus-preserving pancreatoduodenectomy with lymphadenectomy. The resected specimen contained a cystic lesion, 10 x 10 mm in diameter, in the head of the pancreas. Histological examination revealed that the dilated main pancreatic duct and the branch ducts were composed of intraductal papillary mucinous adenoma with mild atypia. No evidence of carcinoma was detected in the specimen. Incidentally, a 3-mm nodule consisting of small neuroendocrine cells was found in the main pancreatic duct. The cells demonstrated positive staining for chromogranin A, synaptophysin, and glucagon but negative staining for insulin and somatostatin. Therefore, the 3-mm nodule was diagnosed as a PEN. Since the mitotic count per 10 high-power fields was less than 2 and the Ki-67 index was less than 2%, the PEN was pathologically classified as low-grade (G1) according to the 2010 World Health Organization (WHO) criteria. Herein, we review the case and relevant studies in the literature and discuss issues related to the synchronous occurrence of the relatively rare tumors, PEN and IPMN.

The authors fabricated micropatterns with inclined sidewalls in a glass-like carbon (GC) mold to thermal imprint on a glass substrate, and succeeded in controlling its inclination angle. The technology comprised three features: (1) A Si-containing photoresist was used with its etching resistance higher than that of the conventional photoresist; (2) the inclination angle of pattern's sidewalls was controlled by a defocus UV exposure technique; and (3) a GC substrate was etched to form a mold by using a Si-containing photoresist structure with inclined sidewalls as a masking layer; the technique was also used to control the inclination angle of the trench's sidewalls in the GC mold. The authors input different focus offset values to defocus the image in order to control the intensity distribution of UV lights within a film of Si-containing photoresist that was spin-coated on a polished GC wafer. In the next step, GC was etched by a 19:1 mixture of O2 and CHF3 which then created a trench structure with inclined sidewalls according to the variations in local masking thicknesses. By changing the focus offset in the UV exposure system from 0 to −12 μm, the inclination angle of the Si-containing photoresist microstructures was varied from 17° to 40°. With these changes, the range of the angles of GC molds became 6° to 17°. Then by thermal imprinting on Pyrex glass and quartz, these numbers expanded from 10° to 32°.

The surface quality of a mold is one of the major factors in imprint lithography as it determines the final surface quality and the minimum size of the replicated patterns. This paper describes a process for O2-based reactive ion etching (RIE) of glassy carbon (GC) without encountering any micro masking effect. Glassy carbon, because of its attractive properties such as its surface inertness, thermal stability and extraordinary hardness, has drawn much interest as a mold material for high-temperature imprinting on glasses and metals. Etch profiles with highly smooth surfaces free of micro masking effects were achieved by adding SF6 to the etching gas. The fraction of SF6 in the gas mixture (ranging from 0.1 to 0.6) showed little change in the quality of the etched surface, but it did lead to a proportional decrease in the etch rate of GC. A reasonable GC etch rate (115?120 nm min?1) and a smooth etch surface were obtained using SF6 at a fraction 0.2 or below. Using electron beam lithography (EBL), and processing under the established SF6/O2 RIE conditions, GC molds were fabricated and successfully applied to thermal imprinting onto glass and metals.

In this study, we demonstrated a process for fabricating a dual damascene opening in a chemically amplified negative UV photoresist, such as SU-8. The process is based on a UV-assisted thermal-imprinting process, which involved UV pretreatment and thermal imprinting using a Ni mold. After establishing process parameters (e.g., adhesion enhancing, UV pre-treating, thermal imprinting, and etch back conditions) for the given geometry and dimensions of the mold pattern, we could successfully form 25-µm-deep trenches with a 10 µm line-and-space pattern and 45 µm-deep via holes in SU-8/Si samples by UV-assisted thermal imprinting, followed by O2/CHF3 reactive ion etching (RIE). Delamination defects could be avoided with the help of adhesion enhancement treatment. The process studied here showed great potential in reducing time and cost compared with the standard photolithographic dual damascene process.

The authors are developing an on-fiber device that uses a quartz fiber as a substrate material and a large-area display and a wearable health monitor by woven fibers with embedded electrical circuit. The electrical circuit will be formed by inserting some electroconductive material into the concave pattern by inkjet and electroless-plating after thermally imprinting on the surface of the quartz fiber. To imprint the quartz fiber, a mold should be able to withstand the high temperature of 1400°C. Therefore, a mold for quartz imprinting on quartz fiber was fabricated with a glasslike carbon substrate polished by chemical-mechanical-polishing. Mold patterns with high accuracies were processed by applying microelectromechanical system fabrication techniques such as photolithography and reactive ion etching. Precise patterns with 5μm minimum linewidths were transferred on the front surface of a 200μm square quartz fiber by thermal nanoimprint technology. The width of the imprinted quartz fibers grew from 200to...

An 83-year-old man underwent computed tomography during a routine check-up due to a history of surgical treatment for pancreatic cancer. Two tumors were detected in the anterior segment of the liver. A needle biopsy of the larger tumor was performed, and pathological examination showed that the tumor was a poorly differentiated hepatocellular carcinoma. Resection was not performed considering the patient's poor physical condition. Thus, transcatheter arterial chemoembolization and radiofrequency ablation of the tumors were performed. Three months later, residual tumor of the larger lesion and multiple pulmonary metastases were detected. This time, continuous hepatic arterial infusion chemotherapy was performed. Although the pulmonary metastases markedly reduced, tumor thrombi appeared in the right portal vein on computed tomography. Finally, sorafenib was administered, which led to disappearance of the tumor thrombi and no other signs of recurrence 8 months after initiation of sorafenib on computed tomography. Although sorafenib administration has continued at reduced doses of 200 mg per day or less due to hypertension, complete response has persisted for the past 34 months. It is noteworthy that sorafenib has been given at reduced doses, but a long-term complete response is maintained in a patient who had portal tumor thrombi and distant metastasis. Herein, we present this rare case of advanced hepatocellular carcinoma controlled with reduced doses of sorafenib following multidisciplinary therapy, describe our single center experience with sorafenib use in patients with hepatocellular carcinoma, and review previous reports that focused on dose reduction of sorafenib.