• Investigative Magnetic Resonance Imaging
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• v.12 no.2
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• pp.178-187
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• 2008

Purpose : To evaluate and compare the diagnostic accuracy of MRI and ultrasound(US) for estimation of invasion depth of gastric carcinoma by correlation with histopathologic findings in vitro and to find out the best MR pulse sequence for detection and accurate delineation of tumor. Materials and Methods : Resected specimen of total or subtotal gastrectomy from 53 patients with gastric carcinoma were done of imaging studies of MRI and US. And US was examined by using high frequency linear transducer for tumor invasion depth by a radiologist. In each case, both imaging findings of MRI and US were evaluated independently for tumor detection and invasion depth by consensus of two radiologists and were compared the diagnostic accuracy between two imaging modalities according to the histopathologic findings. MR imaging with five MR pulse sequences, spin echo T1 and in- and out-of phase gradient echo T1 weighted images, FSE and SSFSE T2 weighted images, were performed. Five MR pulse sequences were evaluated and compared on the point of detection and accurate distinction of tumor from surrounding normal tissue. Results : In EGC, diagnostic accuracy of US(77%) was superior than that of MRI(59%) but no statistically significant difference was noted between two imaging modalities(p=0.096). In AGC, both imaging modalities of MRI and US showed relatively high diagnostic accuracy as 97% and 84% respectively. Diagnostic accuracy of MRI was statistically better than that of US at the significant level(p<0.001). The best MR pulse sequence among five in each specimen was FSE T2WI(75.5%, 40/53) in both EGC and AGC. In AGC, FSE T2WI showed excellent imaging quality by showing very high ratio (93.5%, 29/31) of accurate delineation of tumor. Conclusion : MRI and US show relatively high diagnostic accuracy in the evaluation of tumor invasion depth of resected specimen in AGC. The most excellent pulse sequence of MRI for the evaluation of tumor invasion depth is FSE T2WI on the point of detection and accurate delineation of tumor in both EGC and AGC.

• Journal of radiological science and technology
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• v.31 no.2
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• pp.141-147
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• 2008

Thyroid nodules are a common disease in clinical practice. Fine needle aspiration (FNA) is an accurate and safe method for the diagnosis of thyroid nodules. One of the limitations of FNA is the variable rate of unsatisfactory specimens, especially in small sized, deep seated or complex cystic nodules. To overcome this problem, ultrasound-guided FNA (US-FNA) has been widely used. In this study, the clinical usefulness of US-FNA cytology in thyroid nodules was investigated. Female to male ratio was 6.58:1. The incidence of nodules were 157 (43.1%) cases on the right, 130 (35.7%) cases on the left and 9 (2.5%) cases in isthmus. Total 139 cases (38.2%) belong to less than 1cm and 225 cases (61.8%) belong to more than 1cm. As for the echo type in the nodules, solid types were 255(70.1%), cystic type 39 (10.7%) cases, and the percentage of mixed type was 19.2%. The results show that US-FNA reduces the possibility of unsatisfactory cytologic specimens and the rate of false-negative diagnosis, and improves the diagnostic accuracy in investigation thyroid nodules.

• The Journal of the Korea Contents Association
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• v.13 no.5
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• pp.303-310
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• 2013

Thyroid nodular disease is the most frequently appeared in thyroid disease. Thyroid ultrasonography offers location of nodules, size, the number, information of internal echo characteristic. Thus, it makes possible to sort high-risk nodule containing high possibility about thyroid cancer and to induct precisely when take a Fine Needle Biopsy Aspiration. On thyroid nodule, the case which is diagnosed as malignant is less than 5% but screening test is very important on ultrasound and also must be reduced unnecessary procedure. Therefore, in this study an approach for describing a region is to quantity its texture content. We applied TFA algorithm on case which has been pathologically diagnosed as papillary thyroid cancer. we obtained experiment image which set the ROI on ultrasound and cut the $50{\times}50$ pixel size, histogram equalization. Consequently, Disease recognition detection efficiency of GLavg, SKEW, UN, ENT parameter were high as 91~100%. It is suggestion about possibility on CAD which distinguishes thyroid nodule. In addition, it will be helpful to differential diagnosis of thyroid nodule. If the study on additional parameter algorithm is continuously progressed from now on, it is able to arrange practical base on CAD and it is possible to apply various disease in the thyroid US.

• Journal of Korea Multimedia Society
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• v.13 no.7
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• pp.1044-1050
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• 2010

Endoscopic ultrasonography is a medical procedure in endoscopy combined with ultrasound to obtain images of the internal organs. It is useful to have a predictive pathological manifestation since a doctor can observe tumors under mucosa. However, it is often subjective to judge the degree of malignant degeneration of tumors. Thus, in this paper, we propose a feature analysis procedure to make the pathological manifestation more objective so as to improve the accuracy and recall of the diagnosis. In the process, we extract the ultrasound region from the image obtained by endoscopic ultrasonography. It is necessary to standardize the intensity of this region with the intensity of water region as a base since frequently found small intensity difference is only to be inefficient in the analysis. Then, we analyze the spot region with high echo and calcium deposited region by applying LVQ algorithm and bit plane partitioning procedure to tumor regions selected by medical expert. For detailed analysis, features such as intensity value, intensity information included within two random points chosen by medical expert in tumor region, and the slant of outline of tumor region in order to decide the degree of malignant degeneration. Such procedure is proven to be helpful for medical experts in tumor analysis.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.390-397
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• 2009

Endoscopic ultrasonography is a medical procedure in endoscopy combined with ultrasound to obtain images of the internal organs. It is useful to have a predictive pathological manifestation since a doctor can observe tumors under mucosa. However, it is often subjective to judge the degree of malignant degeneration of tumors. Thus, in this paper, we propose a feature analysis procedure to make the pathological manifestation more objective so as to improve the accuracy and recall of the diagnosis. In the process, we extract the ultrasound region from the image obtained by endoscopic ultrasonography. It is necessary to standardize the intensity of this region with the intensity of water region as a base since frequently found small intensity difference is only to be inefficient in the analysis. Then, we analyze the spot region with high echo and calcium deposited region by applying LVQ algorithm and bit plane partitioning procedure to tumor regions selected by medical expert. For detailed analysis, features such as intensity value, intensity information included within two random points chosen by medical expert in tumor region, and the slant of outline of tumor region in order to decide the degree of malignant degeneration. Such procedure is proven to be helpful for medical experts in tumor analysis.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.2
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• pp.112-119
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• 2015

Photoacoustic microscopy is capable of providing high-resolution molecular images, and its spatial resolution is typically determined by ultrasonic transducers used to receive the photoacoustic signals. Therefore, ultrasonic transducers for photoacoustic microscopy (PAM) should have a high operating frequency, broad bandwidth, and high signal-reception efficiency. Polyvinylidene fluoride (PVDF) is a suitable material. To take full advantage of this material, the selection of the backing material is crucial, as it influences the center frequency and bandwidth of the transducer. Therefore, we experimentally determined the most suitable backing material among EPO-TEK 301, E-Solder 3022, and RTV. For this, three PVDF high-frequency single-element transducers were fabricated with each backing material. The center frequency and -6 dB bandwidth of each transducer were ascertained by a pulse-echo test. The spatial resolution of each transducer was examined using wire-target images. The experimental results indicated that EPO-TEK 301 is the most suitable backing material for a PAM transducer. This material provides the highest signal magnitude and a reasonable bandwidth because a large portion of the energy propagates toward the front medium, and the PVDF resonates in the half-wave mode.

• Journal of the Korean Society of Radiology
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• v.11 no.3
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• pp.153-159
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• 2017

Chronic kidney disease can be treated if it is detected early, but as the disease progresses, it becomes impossible to recover. Finally, renal replacement therapy such as transplantation or dialysis should be used. Ultrasonography is used to diagnose kidney cancer, inflammatory disease, nodular disease, and chronic kidney disease. It is used to identify information about degree of inflammation using information such as kidney size, internal echo characteristics. Currently, the degree of disease in the clinic uses the value of glomerular filtration rate. However, even in ultrasound, changes in the degree of inflammation and disease can be observed. In this study, we used ultrasound images to quantify the changes in brightness, size, cortex, and subclinical changes of the kidney with progression of the disease, and compared them with the glomerular filtration rate used in clinical practice. In 105 cases, we performed 35 cases of normal kidney, 35 cases of early kidney disease, and 35 cases of terminal kidney. The brightness of the cortex of the image was obtained and the difference in brightness between the cortex and the proximal portion was obtained by the slope. The graph of the portion which was not smooth due to the ultrasonic characteristics was used as the function regrass. The size reduction was obtained from the original data. The results were as follows: It was proportional to the glomerular filtration rate. It is considered that the algorithm can be applied to the disease if the algorithm study continues.

• The Journal of the Korean dental association
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• v.53 no.2
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• pp.143-152
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• 2015

Ultrasonography is relatively inexpensive, non-invasive imaging tool and provides real-time imaging. In addition, the images can be obtained repeatedly. But it is not widely used by dentists because it is hard to interpret and technique sensitive. Above all, ultrasonography cannot be used for hard tissue diagnosis. However, ultrasonography can be applied for diagnosis of infection, soft tissue tumor and inflammatory muscle diseases which are commonly found in dental outpatients. Generally, it shows well-defined border, hypoechoic and homogenous structure in case of benign tumor. Malignant tumor appears relatively irregular margin and heterogenous structure. Cyst represents relatively echo-free features compared with benign tumor. Although the general characteristics of abscess are similar with benign tumor, we can observe an increased vascularity and different clinical features. The purpose of this report is to present 3 cases of US images using office-based ultrasonography with their features and discuss the role of office-based ultrasound in dentistry for diagnosis of soft tissue lesions with literature review.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.2
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• pp.46-53
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• 2004

Ultrasonic testing method has been developed to evaluate flaw of adhesive layers in blast tube for the reliability of the rocket nozzle. The ultrasonic reflection from the interface between the steel sheet and the epoxy adhesive is measured with a high-frequency Pulse-echo setup in order to identify contact debonding and missing adhesive in epoxy layer between steel and FRP layers. The steel sheet is resonated by low-frequency ultrasound, and the gap size underneath the measuring location is estimated from the resonance responses. For practical application in industry an automated testing system has been developed where the proposed approach is implemented. The performance of the proposed approach has been verified by actual measurement of gap sizes from the cross-sections of cut specimens using an optical microscope.

• Clinical and Experimental Reproductive Medicine
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• v.15 no.1
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• pp.25-34
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• 1988

The intrafo1licular echoes of cumulus oophoruses within ovarian follicles were assessed with the use of ultrasound in 86 women taking part in an in vitro fertilization(IVF) or gamete intrafallopian transfer(GIFT) program, stimulated with pure follicle-stimulating hormone(FSH)/human menopausal gonadotropin(hMG)/human chorionic gonadotropin (hCG). When intrafo1licular echoes were clearly separated from the follicular wall or relatively dispersed within the follicle, they were considered to be a dissociated cumulus, and when they were only slightly prominent from the follicular wall, they were suspected to be a nondissociated cumulus. A cumulus was seen in 62.1% of the follicles larger than 10 mm diameter and 75.1% of them were dissociated. The larger the follicles in size, the more the cumuluses in number and dissociation. The number of follicles and intrafollicular echoes per woman was not different whether or not she would be pregnant, but the number of dissociated cumuluses was significantly more in pregnant women. The number of observed dissociated cumuluses correlated significantly with the number of recovered mature oocytes. When an intrafollicular echo is seen, it can be taken as evidence of a sign of maturity of that particular follicle and oocyte. Ultrasonographic monitoring of intrafollicular echoes and follicular size is very helpful to predict follicular maturation in ovulation stimulation cycles.