Ho-Taek Song

Morton neuroma: evaluated with ultrasonography and MR imaging.

Objective The purpose of this study was to compare the diagnostic accuracy of both ultrasonography (US) and magnetic resonance imaging (MRI) for the assessment of Morton neuroma. Materials and Methods Our study group was comprised of 20 neuromas from 17 patients, and the neuromas were confirmed on surgery following evaluation with US, MRI, or both US and MRI. The diagnostic criterion for Morton neuroma, as examined by US, was the presence of a round or ovoid, well-defined, hypoechoic mass. The diagnostic criterion, based on MR imaging, was a well defined mass with intermediate to low signal intensity on both the T1- and T2-weighted images. The retrospective comparison between the sonographic and MR images was done by two experienced radiologists working in consensus with the surgical and pathologic correlations. Results The detection rate of Morton neuroma was 79% for 14 neuromas from 11 patients who had undergone US followed by an operation. The detection rate was 76% for 17 neuromas from 15 patients who had undergone MRI and a subsequent operation. The mean size of the examined neuromas was 4.9 mm on the US images and it was 5.1 mm on the MRI studies. Ten neuromas (71%) were 5 mm or less as measured by US, and three neuromas were not detected, whereas on the MRI analysis, 10 neuromas (59%) were 5 mm or less and four neuromas were not visualized. Among the patients examined during postoperative follow-up, symptoms were completely relieved in 85% and the symptoms were partially relieved in 15%. Conclusion US and MR imaging are comparable modalities with high detection rate for the evaluation of Morton neuroma.

Textile electrodes of jacquard woven fabrics for biosignal measurement

In the last few years, textile electrodes have become an interesting topic for physiological monitoring, steadily developing to be applied in innovative wearable sensing systems. The structure of textile electrodes can be fabricated by weaving, knitting, or embroidering conductive yarn and is now commercially available. The upgraded textile electrode is used in biosignal sensing and was designed in the form of a jacquard woven structure to measure the ECG. In the case of knit fabric, which has piezo‐resistive properties, the textile electrodes were developed by using the fabric’s flexible strain gauges in a bio‐monitoring system. However, the piezo‐resistive sensing fabrics have some shortcomings such as low dynamic range, poor repeatability, and performance deterioration after washing or repeated folding. Woven fabric, which is cloth woven in the warp and weft directions, has less strain properties and can be constructed more uniformly than knit fabric. Therefore, due to their more consistent woven structure, jacquard woven fabrics made with conductive yarn can be manufactured evenly on a large scale and consistently maintain their properties. The woven structure of jacquard electrodes consists of a double‐faced weave and is woven with a silver covering yarn in the weft direction. The proposed textile electrodes were composed of two groups made up of warps with either the unremoved 100% warps or the half‐removed 50% warps of jacquard woven electrodes that were convex or flat and were either with or without conductive paste. The ECG measurements for the textile electrodes were repeated three times in resting conditions. The convex jacquard electrodes of the half‐removed 50% warps with the conductive paste resulted in the most significant SNR improvement (33.67 dB). The purpose of this paper was to investigate a method to design jacquard woven electrodes uniformly on a large scale and to apply it feasibly to ECG measurement.

Development of a new tri-block copolymer with a functional end and its feasibility for treatment of metastatic breast cancer

We have developed nanomedicine vehicle based on a biocompatible tri-block copolymer, poly(ethylene glycol)-block-poly(lactic acid)-block-poly(ethylene glycol) (PEG-PLA-PEG) by simple approach without toxic linker to escalate therapeutic efficacy of anticancer agent by enhanced targeting to metastasized breast cancers. The synthesized ABA type copolymer had a low polydispersity index and formed small, highly stable spherical micelles. Furthermore, a functional group at the end site of the copolymer can be decorated with imaging agents and targeting moieties. The doxorubicin loaded micelles (DLM) showed higher drug-loading capacity, faster drug release, and better cell toxicity compared to those using di-block copolymers. DLM efficiently delivered to the metastatic breast cancers in brain and bone and suppressed growing of metastasis. In demonstration of treating metastasized animal model, we present a tri-block copolymer as a potential nanomedicine vehicle to efficiently deliver anticancer drug and to effectively treat metastatic breast cancer.

MicroRNA-200 family members and ZEB2 are associated with brain metastasis in gastric adenocarcinoma

Although the incidence of brain metastasis in gastric cancer is relatively low, its prevalence may increase with improved therapy and longer survival tumors. The molecular mechanisms underlying brain metastases are not well understood. To gain insight into the mechanism of brain metastasis, we studied differences in microRNA (miRNA) expression levels in 8 cases of matched primary gastric adenocarcinoma and brain metastatic adenocarcinoma using the Illumina microRNA microarray chip. We identified 6 upregulated and 2 downregulated miRNAs in all 8 cases simultaneously. Interestingly, 2 out of 8 miRNAs (hsa-miR‑141-3p and hsa-miR-200b-3p) belonged to the miR-200 family. Online microRNA database searching revealed that ZEB2 is the top-ranked target gene for hsa-miR141-3p and hsa-miR-200b-3p, prompting us to focus ZEB2 expression in brain metastatic adenocarcinoma. We confirmed that ZEB2 expression was markedly downregulated in some brain metastatic samples. In addition, decreased ZEB2 expression was noted by western blot analysis of 2 metastatic gastric adenocarcinoma cell types that were derived by in vivo selection following intracardiac injection of gastric cancer cell lines. In conclusion, we demonstrate that expression of miRNA-200 family members and ZEB2 are associated with brain metastases of gastric adenocarcinoma, not only in matched patient samples, but also in metastatic cell lines that were derived by in vivo selection.

Quantitative T 2 Mapping of Knee Cartilage: Comparison between the Synthetic MR Imaging and the CPMG Sequence

The purpose was to evaluate the feasibility of quantitative MRI T2 mapping based on the quantitative MRI (QRAPMASTER) sequence for the quantitative assessment of knee cartilage. The T2 values from the phantom study showed excellent correlation between the two techniques (r2 = 0.998). The cartilage T2 values exhibited strong correlations (r2 = 0.867–0.982). Quantitative MRI (qMRI) T2 mapping can be used as an alternative to multi-echo T2 mapping, with relatively short scan time.

Abstract 2067: Hyperpolarized 13C-pyruvate MRS quantitatively monitor the therapeutic efficacy of adjuvant metformin combined RT in brain metastasis from triple negative breast cancer

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CAnnIntroductionnnThe hyperpolarized 13C-pyruvate is a robust imaging biomarker to evaluate the metabolic status of cancer to monitor the anti-cancer therapeutic effect and to predict the prognosis as earliest as possible by 10,000 fold increase of MRS sensitivity. According to the clinical epidemiological research, metformin reduces cancer incidence or mortality in type II diabetes patients. In this study, we investigated the anti-cancer metabolic effect of metformin as an adjuvant for the radiation therapy to treat brain metastasis from triple negative breast cancer in nude mouse model by measuring the metabolic flux through the hyperpolarized 13C-pyruvate MRS.nnMethodsnnSix weeks old BALB/C nude mice were stereotactically implanted 2×105 MDA-MB-231-luciferase breast cancer cells in the striatum of brain. After 1 week from tumor implantation, animals were randomly divided into 4 groups: vehicle (distilled water), oral metformin alone (MET), radiation treatment (RT), and radiation combined with adjuvant oral metformin treatment (METRT). Mice were treated with 300 mg/kg of oral metformin for 5 days in a week from week 1 until when the animals die. MRI and 13C MRS was performed at week 2 and week 3, before and after treatment. Brain tumors were irradiated at week 2 with 3Gy for 5 consecutive days. MRI and MRS was performed at 9.4T Bruker MRI scanner using 20mm surface dual tuned 1H-13C coil. 75mmole of hyperpolarized [1-13C] pyruvate was injected via tail vein in all mice. Metabolic flux was calculated as lactate/pyruvate ratio. The progression and the response to treatment was also monitored by bioluminescence imaging. Paraffin sections were stained with H&E for histological evaluation.nnResultsnnThere was no difference in tumor growth and metabolic flux rate between vehicle and MET alone groups. Vehicle group showed 260% increase in tumor mass, whereas RT group showed only 39% increase in tumor volume. 13C MRS showed 60% decrease in lactate/pyruvate flux ratio in RT group, whereas vehicle group showed 60% increase in metabolic flux ratio. Interestingly, the tumor volume was significantly regressed and 13C-lactate flux was significantly decreased in METRT group after treatment. Bioluminescence imaging showed time-dependent increasing flux in vehicle group, but RT and METRT groups showed decreased photon flux activity. In comparison of METRT with RT alone group, bioluminescence activity was significantly decreased in METRT group. H&E staining of histological sections showed significant tumor necrosis and decreased cellularity in METRT group.nnConclusionnnHyperpolarized 13C-pyruvate MRS informs the adjuvant therapeutic effect of metformin and RT in brain metastasis from triple negative breast cancer.nnCitation Format: Young-suk Choi, Han-Sol Lee, Jung-Sung Lee, Hyun-Jin Park, Ju-Hyun Lee, Eun-Kyung Wang, Seung-Wook Yang, Eunhae Joe, Soo Hyeon Lee, Dong-Hyun Kim, Ho-Taek Song. Hyperpolarized 13C-pyruvate MRS quantitatively monitor the therapeutic efficacy of adjuvant metformin combined RT in brain metastasis from triple negative breast cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2067. doi:10.1158/1538-7445.AM2014-2067

Determination of optimal imaging mode for ultrasonographic detection of subdermal contraceptive rods: comparison of spatial compound, conventional, and tissue harmonic imaging methods.

Objective To determine which mode of ultrasonography (US), among the conventional, spatial compound, and tissue-harmonic methods, exhibits the best performance for the detection of Implanon® with respect to generation of posterior acoustic shadowing (PAS). Materials and Methods A total of 21 patients, referred for localization of impalpable Implanon®, underwent US, using the three modes with default settings (i.e., wide focal zone). Representative transverse images of the rods, according to each mode for all patients, were obtained. The resulting 63 images were reviewed by four observers. The observers provided a confidence score for the presence of PAS, using a five-point scale ranging from 1 (definitely absent) to 5 (definitely present), with scores of 4 or 5 for PAS being considered as detection. The average scores of PAS, obtained from the three different modes for each observer, were compared using one-way repeated measure ANOVA. The detection rates were compared using a weighted least square method. Results Statistically, the tissue harmonic mode was significantly superior to the other two modes, when comparing the average scores of PAS for all observers (p < 0.00-1). The detection rate was also highest for the tissue harmonic mode (p < 0.001). Conclusion Tissue harmonic mode in uS appears to be the most suitable in detecting subdermal contraceptive implant rods.