• Title/Summary/Keyword: T1WI

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A Design and Manufacture of Triple Band Antenna with Line and Arc shaped Strips for WLAN/WiMAX system (직선과 원호가 결합된 WLAN/WiMAX용 삼중대역 안테나 설계 및 제작)

  • Kwon, Man-Jea;Yoon, Joong-Han
    • The Journal of the Korea institute of electronic communication sciences
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    • v.13 no.1
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    • pp.15-22
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    • 2018
  • In this paper, a microstrip-fed triple-band monopole antenna for WLAN/WiMAX applications was proposed. The proposed antenna is consist of two arc-shaped and one strip line structure, then get the three current path and then designed in order to get triple resonant characteristics. We carried out simulation about parameters. Taking account of coupling effect, Adjusted the length of the two arc-shaped and one strip line, we get the optimized parameters. The proposed antenna is fabricated on an FR-4 substrate, the dielectric constant is 4.4, and total size is $23.5mm(W1){\times}32.0mm(L1){\times}1.0mm(t)$, and its proposed antenna size is $21.0mm(W6){\times}31.0mm(L7)$. From the measured results, return loss of the proposed antenna satisfied return loss 927 MHz (1.844~2.771 GHz), 926 MHz (3.33~4.256 GHz), and 1,415 MHz (5.13~6.545 GHz). And measured results of gain and radiation patterns displayed for operating bands.

The Detection of Intracranial Calcification by MR : Experimental Model (실험적 모델을 이용한 자기공명영상에서 석회화의 인지)

  • 박승진
    • Progress in Medical Physics
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    • v.5 no.1
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    • pp.3-12
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    • 1994
  • Purporse : It is known that detection of calcification by MRI is difficulty in intracranial calcified lesions, but author tried to evaluate the signal intensity image of calcification by MR with experimental model. Subjects & Methods : Author analyzed and compared with values of calcium carbonate and hydroxyapatite phantoms by each concentration (10, 20, 30, 40, 50%) and size(1-10mm), measured ROI attenuating from CT and MRI(TlWI & T2WI). Results : The high concentration of calcium carbonate is, the lower the signal intensity of calcium carbonate phantom is both T1 & T2WI. For concentration of Hydroxyapatite of up to 30% by weight the signal intensity on standard T1 weighted images increased but subsequently decreased. Hyperintensity does not preclude calcification as a cause of the signal alteration-an observation that all radiologists interpreting MR images need to be aware of. Conclusion: The signal intensity of intracranial calcification is various on MR imaging in concerning with components, concentration, & size of calcification, and especially high signal intensity of intracranial calcification noted differencial diagnosis.

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Early Bone Marrow Edema Pattern of the Osteoporotic Vertebral Compression Fracture : Can Be Predictor of Vertebral Deformity Types and Prognosis?

  • Ahn, Sung Eun;Ryu, Kyung Nam;Park, Ji Seon;Jin, Wook;Park, So Young;Kim, Sung Bum
    • Journal of Korean Neurosurgical Society
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    • v.59 no.2
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    • pp.137-142
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    • 2016
  • Objective : To evaluate whether an early bone marrow edema pattern predicts vertebral deformity types and prognosis in osteoporotic vertebral compression fracture (OVCF). Methods : This retrospective study enrolled 64 patients with 75 acute OVCFs who underwent early MRI and followed up MRI. On early MRI, the low SI pattern of OVCF on T1WI were assessed and classified into 3 types (diffuse, globular or patchy, band-like). On followed up MRI, the vertebral deformity types (anterior wedge, biconcave, crush), degree of vertebral body height loss, incidence of vertebral osteonecrosis and spinal stenosis were assessed for each vertebral fracture types. Results : According to the early bone marrow edema pattern on T1WI, 26 vertebrae were type 1, 14 vertebrae were type 2 and 35 vertebrae were type 3. On followed up MRI, the crush-type vertebral deformity was most frequent among the type 1 OVCFs, the biconcave-type vertebral deformity was most frequent among the type 2 OVCFs and the anterior wedge-type vertebral deformity was most frequent among the type 3 OVCFs (p<0.001). In addition, type 1 early bone marrow edema pattern of OVCF on T1WI were associated with higher incidence of severe degree vertebral body height loss, vertebral osteonecrosis and spinal stenosis on the follow up MRI. Conclusion : Early bone marrow edema pattern of OVCF on T1WI, significant correlated with vertebral deformity types on the follow up MRI. The severe degree of vertebral height loss, vertebral osteonecrosis, and spinal stenosis were more frequent in patients with diffuse low SI pattern.

Effect of Metals used in Orthopedic on Magnetic Resonance Imaging I (정형보철용 금속이 자기공명영상에 미치는 영향 I)

  • Kim, Hyeong-Gyun;Choi, Seong-Dae
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.11 no.4
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    • pp.46-50
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    • 2012
  • Stainless steel and titanium used for orthopedic prosthetic metal, magnetic resonance imaging was measured quantitatively the extent of distortion. Based on reading tests at varying metal magnetic resonance imaging (MRI) were investigated. To two image acquisition conditions for having three metal bodies mutually quantitative it compared analyzed the image of cross direction and the image of lengthwise. As for the distortion of the magnetic resonance image, as for the distortion of image it became small in the order of Clip, Strainless and Titanium. In addition, with T1WI and T2WI which are image acquisition condition T2WI the distortion of image became small. As for the distortion of the image by the metal, you could see the distortion of image in elliptical shape, the metal a bigger image distortion appeared in many parts. If clinical doctor has the condition of the same operation, use the Titanium material, it can, raising the diagnostic value of magnetic resonance image inspection after the operating from Stainless.

A Study of the Quantitative, Qualitative Analysis on Optimizing Diagnostic Imaging Device Selection in Nasopharynx MRI (비 인두 자기공명 검사 시 최적의 진단영상 장치 선택에 관한 정량, 정성적 평가에 관한 연구)

  • Goo, Eun-Hoe
    • Journal of the Korean Society of Radiology
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    • v.13 no.7
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    • pp.1035-1043
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    • 2019
  • The object of is this research is to find out the optimal Tesla by evaluating SNR and CNR, after testing 1.5 T and 3.0 T. The randomly selected patients tested by nasopharynx MRI transmitted in PACS were applied to the research. Two MRI units(1.5 T, 3.0 T) was used for analyzing the data. As a method of analysis, in T1W highlighting and T1 fat removal images, we set up a certain area of interest and evaluated the SNR and CNR on tongue, spinal cord, masseter muscle, fat, parotid gland, and tumor tissue. We evaluated the SNR and CNR by quantitative analysis of six tissue, measuring the quality of images for uniform fat removal, magnetic sensitivity artifact on a four-point scale by qualitative analysis. The statistical significance of this date analysis was based on independent sample verification and was accepted when the P value was less than 0.05. As a result of analysis of both devices, 3.0 T was high in the quantitative evaluation, while 1.5 T was high in the qualitative evaluation. Considering the advantages and disadvantages of each device, and if the device is selected complementarily and applied to patients, it is believed that it will provide the optimal information.

An Intradural Extramedullary Hemangioblastoma of Distal Spinal Cord - A Case Report - (척수 원위부에 발생한 경막내수막외 혈관아세포종 - 증례보고 -)

  • Park, Sung-Ho;Cho, Joon;Youn, Seung-Whan;Chang, Sang-Keun
    • Journal of Korean Neurosurgical Society
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    • v.29 no.11
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    • pp.1523-1526
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    • 2000
  • It has been known that hemangioblastoma of spinal cord occurs about 4% of all the spinal tumors. The authors present a rare case of intradural extramedullary(IDEM) hemangioblastoma of distal spinal cord in 41-year-old male patient. This IDEM mass at the level of conus medullaris showed iso-signal intensities on T1-weighted image(T1-WI) and high-signal intensities on T2-WI, and was enhanced homogeneously on MRI. At surgery, T12- L1 total laminectomy and enbloc mass removal were performed. This IDEM hemangioblastoma was confirmed by histopathologic findings. For less postoperative complication in IDEM tumors, we suggest that precise preoperative evaluation and complete excision via proper surgical approach to distal conus should be reemphasized.

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Primary Occipital Malignant Melanoma

  • Oh, Jong-Yang;Joo, Won-Il;Rha, Hyoung-Kyun;Kim, Young-Woo
    • Journal of Korean Neurosurgical Society
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    • v.41 no.1
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    • pp.39-42
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    • 2007
  • Primary intracranial melanoma is uncommon. These tumors most commonly occur at the temporal lobe, cerebellum and cerebellopontine angle. We report a case of intracranial malignant melanoma of the occipital lobe in a 60-year-old man who presented with headache and visual disturbance. The mass showed hyperintensity on T1-weighted images and hypointensity on T2-weighted magnetic resonance images. He underwent gross total removal of tumor and received radiotherapy. Follow-up imaging studios showed neither recurrence nor any signs of residual disease for 4 months.

Cross-Technology Localization: Leveraging Commodity WiFi to Localize Non-WiFi Device

  • Zhang, Dian;Zhang, Rujun;Guo, Haizhou;Xiang, Peng;Guo, Xiaonan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.15 no.11
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    • pp.3950-3969
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    • 2021
  • Radio Frequency (RF)-based indoor localization technologies play significant roles in various Internet of Things (IoT) services (e.g., location-based service). Most such technologies require that all the devices comply with a specified technology (e.g., WiFi, ZigBee, and Bluetooth). However, this requirement limits its application scenarios in today's IoT context where multiple devices complied with different standards coexist in a shared environment. To bridge the gap, in this paper, we propose a cross-technology localization approach, which is able to localize target nodes using a different type of devices. Specifically, the proposed framework reuses the existing WiFi infrastructure without introducing additional cost to localize Non-WiFi device (i.e., ZigBee). The key idea is to leverage the interference between devices that share the same operating frequency (e.g., 2.4GHz). Such interference exhibits unique patterns that depend on the target device's location, thus it can be leveraged for cross-technology localization. The proposed framework uses Principal Components Analysis (PCA) to extract salient features of the received WiFi signals, and leverages Dynamic Time Warping (DTW), Gradient Boosting Regression Tree (GBRT) to improve the robustness of our system. We conduct experiments in real scenario and investigate the impact of different factors. Experimental results show that the average localization accuracy of our prototype can reach 1.54m, which demonstrates a promising direction of building cross-technology technologies to fulfill the needs of modern IoT context.

Proposal of Traffic Management Strategy between Hierarchical Mobile-WiMAX/WLAN Networks (계층적 Mobile-WiMAX/WLAN 네트워크에서의 트래픽 관리 전략에 관한 연구연구)

  • Moon, Tae-Wook;Kim, Moon;Cho, Sung-Jun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.1
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    • pp.153-160
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    • 2009
  • A hierarchical network between Mobile-WiMAX and WLAN systems is to make it possible to utilize wireless internet services including time sensitive applications such as VoIP, VOD, visual telephony etc. During the process of vertical handoff decision from Mobile-WiMAX to WLAN hotspot, vertical handoff delay causes user dissatisfaction because it doesn't provide the seamless wireless internet service. We make use of type of service (ToS) parameters in IEEE 802.16e specification as the criterion parameter of vertical handoff decision process in hierarchical Mobile-WiMAX/WLAN networks. In this paper, we propose the process of vertical handoff decision for seamless wireless internet service which is sensitive to time delay. If type of service is time sensitive application, the decision of vertical handoff is withdrawn until the service is terminated. In focus on user satisfaction, if the proposed traffic management strategy in hierarchical Mobile-WiMAX/WLAN networks is used, user will utilize seamless wireless internet services including time sensitive applications.

Comparison of Single- and Multi-Echo Susceptibility-Weighted Imaging in Detecting Cerebral Arteriovenous Shunts: A Preliminary Study (뇌동정맥단락 진단에서의 단일 에코 자화율 강조영상과 다중 에코 자화율 강조영상의 비교: 예비 연구)

  • Seung Wan Han;Jae Ho Shin;Yon Kwon Ihn;Seung Ho Yang;Jae Hoon Sung
    • Journal of the Korean Society of Radiology
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    • v.84 no.1
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    • pp.226-239
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    • 2023
  • Purpose To compare the sensitivities of T2-weighted image (T2WI) and susceptibility-weighted imaging (SWI) in detecting cerebral arteriovenous fistula (AVF), cerebral arteriovenous malformation (AVM), and carotid-cavernous sinus fistula (CCF), and to qualitatively evaluate single-echo SWI (s-SWI) and multi-echo SWI (m-SWI) in characterizing vascular lesions. Materials and Methods From January 2016 to December 2021, cerebral angiography-proven lesions were recruited. The sensitivities of T2WI and SWI in detecting vascular lesions were compared using McNemar's test. Qualitative evaluations of s-SWI and m-SWI were categorized to be of poor, average, or good quality and compared using Fisher's exact test. Results A total of 24 patients (mean age: 61 years, 12 female, and 12 male) were enrolled. Twenty patients underwent s-SWI or m-SWI, and four patients underwent both. AVF, AVM, and CCF were diagnosed in 10, 11, and 3 patients, respectively. SWI demonstrated higher sensitivity compared to that of T2WI (82.1% vs. 53.6%, p = 0.013). m-SWI showed better image quality compared to that of s-SWI (good quality, 83.3% vs. 25.0%, p = 0.009). Conclusion SWI demonstrated a higher sensitivity for detecting cerebral arteriovenous shunts compared to that of T2WI. m-SWI exhibited better image quality compared to that of s-SWI in characterizing vascular lesions.