• Title, Summary, Keyword: MRI

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USABILITY EVALUATION OF PLANNING MRI ACQUISITION WHEN CT/MRI FUSION OF COMPUTERIZED TREATMENT PLAN (전산화 치료계획의 CT/MRI 영상 융합 시 PLANNING MRI영상 획득의 유용성 평가)

  • Park, Do-Geun;Choe, Byeong-Gi;Kim, Jin-Man;Lee, Dong-Hun;Song, Gi-Won;Park, Yeong-Hwan
    • The Journal of Korean Society for Radiation Therapy
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    • v.26 no.1
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    • pp.127-135
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    • 2014
  • Purpose : By taking advantage of each imaging modality, the use of fused CT/MRI image has increased in prostate cancer radiation therapy. However, fusion uncertainty may cause partial target miss or normal organ overdose. In order to complement such limitation, our hospital acquired MRI image (Planning MRI) by setting up patients with the same fixing tool and posture as CT simulation. This study aims to evaluate the usefulness of the Planning MRI through comparing and analyzing the diagnostic MRI image and Planning MRI image. Materials and Methods : This study targeted 10 patients who had been diagnosed with prostate cancer and prescribed nonhormone and definitive RT 70 Gy/28 fx from August 2011 to July 2013. Each patient had both CT and MRI simulations. The MRI images were acquired within one half hour after the CT simulation. The acquired CT/MRI images were fused primarily based on bony structure matching. This study measured the volume of prostate in the images of Planning MRI and diagnostic MRI. The diameters at the craniocaudal, anteroposterior and left-to-right directions from the center of prostate were measured in order to compare changes in the shape of prostate. Results : As a result of comparing the volume of prostate in the images of Planning MRI and diagnostic MRI, they were found to be $25.01cm^3$(range $15.84-34.75cm^3$) and $25.05cm^3$(range $15.28-35.88cm^3$) on average respectively. The diagnostic MRI had an increase of 0.12 % as compared with the Planning MRI. On the planning MRI, there was an increase in the volume by $7.46cm^3$(29 %) at the transition zone directions, and there was a decrease in the volume by $8.52cm^3$(34 %) in the peripheral zone direction. As a result of measuring the diameters at the craniocaudal, anteroposterior and left-to-right directions in the prostate, the Planning MRI was found to have on average 3.82cm, 2.38cm and 4.59cm respectively and the diagnostic MRI was found to have on average 3.37cm, 2.76cm and 4.51cm respectively. All three prostate diameters changed and the change was significant in the Planning MRI. On average, the anteroposterior prostate diameter decrease by 0.38cm(13 %). The mean right-to-left and craniocaudal diameter increased by 0.08cm(1.6 %) and 0.45cm(13 %), respectively. Conclusion : Based on the results of this study, it was found that the total volumes of prostate in the Planning MRI and the diagnostic MRI were not significantly different. However, there was a change in the shape and partial volume of prostate due to the insertion of prostate balloon tube to the rectum. Thus, if the Planning MRI images were used when conducting the fusion of CT/MRI images, it would be possible to include the target in the CTV without a loss as much as the increased volume in the transition zone. Also, it would be possible to reduce the radiation dose delivered to the rectum through separating more clearly the reduction of peripheral zone volume. Therefore, the author of this study believes that acquisition of Planning MRI image should be made to ensure target delineation and localization accuracy.

Analysis of Health Insurance Standards and Utilization of MRI in Korea: Based on Health Insurance Claim Data (한국의 MRI 건강보험 급여기준 및 진료이용에 관한 연구)

  • Cho, Young-Kwon
    • Journal of the Korean Society of Radiology
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    • v.12 no.7
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    • pp.869-877
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    • 2018
  • This study analyzed the current status of MRI (frequency, amount of treatment) based on the history of application of the MRI health insurance benefit standard and health insurance claim data. MRI examinations began as a health insurance benefit in 2005. In 2005, the indications were restricted for some diseases, but coverage for benefits in 2010, 2013, 2016, and 2018 was expanded. In 2021, the Ministry of Health and Welfare decided to apply health insurance for all MRI examinations. From 2010 to 2017, the number of MRI examinations increased by 86.7% in 2017 compared to 2010, and the amount of treatment increased by 53.5%. According to general characteristics, the number of MRI examinations was higher in women than in men. By age, the number of examinations was the highest among ages 70-79. Outpatient examinations were more frequent than inpatient examinations, and the number of examinations in the tertiary hospitals was the highest among the types of hospitals. The number of brain MRI examinations was the highest in each exam site. In December 2013, the standard of MRI was expanded for heart disease and Crohn's disease, the number of cardiac MRI and abdominal MRI examinations increased in 2014 compared to 2013. However, the number of examinations is small and not associate with the disease, it would be difficult to say that it affected the increase in the total number of MRI examinations. To assess health insurance sustainability and policy effectiveness, monitoring will be necessary.

The Feasibility Study of MRI-based Radiotherapy Treatment Planning Using Look Up Table (Look Up Table을 이용한 자기공명영상 기반 방사선 치료계획의 타당성 분석 연구)

  • Kim, Shin-Wook;Shin, Hun-Joo;Lee, Young-Kyu;Seo, Jae-Hyuk;Lee, Gi-Woong;Park, Hyeong-Wook;Lee, Jae-Choon;Kim, Ae-Ran;Kim, Ji-Na;Kim, Myong-Ho;Kay, Chul-Seung;Jang, Hong-Seok;Kang, Young-Nam
    • Progress in Medical Physics
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    • v.24 no.4
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    • pp.237-242
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    • 2013
  • In the intracranial regions, an accurate delineation of the target volume has been difficult with only the CT data due to poor soft tissue contrast of CT images. Therefore, the magnetic resonance images (MRI) for the delineation of the target volumes were widely used. To calculate dose distributions with MRI-based RTP, the electron density (ED) mapping concept from the diagnostic CT images and the pseudo CT concept from the MRI were introduced. In this study, the look up table (LUT) from the fifteen patients' diagnostic brain MRI images was created to verify the feasibility of MRI-based RTP. The dose distributions from the MRI-based calculations were compared to the original CT-based calculation. One MRI set has ED information from LUT (lMRI). Another set was generated with voxel values assigned with a homogeneous density of water (wMRI). A simple plan with a single anterior 6MV one portal was applied to the CT, lMRI, and wMRI. Depending on the patient's target geometry for the 3D conformal plan, 6MV photon beams and from two to five gantry portals were used. The differences of the dose distribution and DVH between the lMRI based and CT-based plan were smaller than the wMRI-based plan. The dose difference of wMRI vs. lMRI was measured as 91 cGy vs. 57 cGy at maximum dose, 74 cGt vs. 42 cGy at mean dose, and 94 cGy vs. 53 at minimum dose. The differences of maximum dose, minimum dose, and mean dose of the wMRI-based plan were lower than the lMRI-based plan, because the air cavity was not calculated in the wMRI-based plan. These results prove the feasibility of the lMRI-based planning for brain tumor radiation therapy.

Clinical Applications of Breast MRI (유방자기공명영상의 임상 적용)

  • Cho, Nariya;Moon, Woo-Kyung
    • Investigative Magnetic Resonance Imaging
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    • v.13 no.1
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    • pp.1-8
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    • 2009
  • Breast MRI is a cutting-edge technology in the diagnosis and intervention of breast abnormalities. Over the last decade, breast MRI has evolved from a research field to a clinical field. Radiologists should understand the indications, how to obtain adequate images, and how to interpret and report their findings. Breast MRI is now used in the differentiation of benign from malignant mass, preoperative staging of breast cancer patients, assessment of tumor response to neoadjuvant chemotherapy, and evaluation of women with breast implants. It can also be used as a supplemental screening modality for high-risk women. Qualified radiologists and adequate MRI technique are crucial for the success of these purposes. This review is focused on the indication, standardized use of lexicon and categorization of breast MRI.

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Evaluation between 3.0 T vs 1.5 T MRI in Detection of Brain Metastasis using Double Dose Gd-DTPA (뇌전이 종양의 발견에 있어서 Doble dose Gd-DTPA를 이용한 3 T MRI와 1.5 T MRI간의 비교연구)

  • Chung, Woo-Suk;Kim, Hyung-Jung;Ahn, Chul-Min;Lee, Jae-Hoon;Hur, Jin;Cho, Eung-Hyuck;Chung, Tae-Sub
    • Investigative Magnetic Resonance Imaging
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    • v.9 no.2
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    • pp.101-108
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    • 2005
  • Purpose : Early detection of small brain metastases is important. The purpose of this study was to compare the detectability of brain metastases according to the size between 1.5 T and 3.0 T MRI. Materials and Methods : We reviewed 162 patients with primary lung cancer who were examined for TNM staging. After administration of double dose of Gd-DTPA, MR imaging was performed with SPGR by 3.0 T MRI and then with T1 SE sequence by 1.5 T MRI. In each patient, three readers performed qualitative assessment. Sensitivity, positive predictive value, and diagnostic accuracy were calculated in 3.0 T and 1.5 T MRI according to size. Using the signal intensity (SI) measurements between the metastatic nodules and adjacent tissue, nodule-to-adjacent tissue SI ratio was calculated. Results : Thirty-one of 162 patients had apparent metastatic nodules in the brain at either 1.5 T or 3.0 T MR imaging. 143 nodules were detected in 3.0 T MRI, whereas 137 nodules were detected at 1.5 T MRI. Six nodules, only detected in 3.0 T MRI, were smaller than 3.0 mm in dimension. Sensitivity, positive predictive value, and diagnostic accuracy in 3.0 T MRI were 100 %, 100 %, and 100 % respectively, and in 1.5 T MRI were 95.8%, 88.3%, and 85.1% respectively. SI ratio was significantly higher in the 3.0 T MRI than 1.5 T MRI (p=0.025). Conclusion : True positive rate of 3.0 T MRI with Gd-DTPA was superior to 1.5 T MRI with Gd-DTPA in detection of metastatic nodules smaller than 3.0 mm.

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Comparison of static MRI and pseudo-dynamic MRI in tempromandibular joint disorder patients (측두하악관절장애 환자에서의 static MRI와 pseudo-dynamic MRI의 비교연구)

  • Lee, Jin-Ho;Yun, Kyoung-In;Park, In-Woo;Choi, Hang-Moon;Park, Moon-Soo
    • Imaging Science in Dentistry
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    • v.36 no.4
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    • pp.199-206
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    • 2006
  • Purpose: The purpose of this study was to evaluate comparison of static MRI and pseudo-dynamic (cine) MRI in temporomandibular joint (TMJ) disorder patients. Materials and Methods: In this investigation, 33 patients with TMJ disorders were examined using both conventional static MRI and pseudo-dynamic MRI. Multiple spoiled gradient recalled acquisition in the steady state (SPGR) images were obtained when mouth opened and closed. Proton density weighted images were obtained at the closed and open mouth position in static MRI. Two oral and maxillofacial radiologists evaluated location of the articular disk, movement of condyle and bony change respectively and the posterior boundary of articular disk was obtained. Results: No statistically significant difference was found in the observation of articular disk position, mandibular condylar movement and posterior boundary of articular disk using static MRI and pseudo-dynamic MRI (P<0.05). Statistically significant difference was noted in bony changes of condyle using static MRI and pseudo-dynamic MRI (P<0.05). Conclusion: This study showed that pseudo-dynamic MRI didn't make a difference in diagnosing internal derangement of TMJ in comparison with static MRI. But it was considered as an additional method to be supplemented in observing bony change.

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Preoperative Detection of Hepatic Metastases from the colorectal Cancers: Comparison of Dual-phase CT scan, Mn-DPDP enhanced MRI, and combination of CT and MRI (대장암의 간 전이 진단: 이중시기 CT, Mn-DPDP 조영증강 MRI, 그리고 CT-MRI 종합 판독의 비교)

  • Shin, Kyung-Min;Kim, Jong-Yeol;Choi, Gyu-Seok;Kim, Hye-Jeong;Lee, Jong-Min;Chang, Yong-Min;Kim, Yong-Seon;Kang, Duk-Sik;Ryeom, Hun-Kyu
    • Investigative Magnetic Resonance Imaging
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    • v.9 no.2
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    • pp.109-116
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    • 2005
  • Purpose : To determine the usefulness of additional Mn-DPDP MRI for preoperative evaluation of the patients with colorectal cancers by comparison of dual-phase CT scan, Mn-DPDP enhanced MRI and combination of CT and MRI. Materials and Methods : Fifty-three colorectal cancer patients with 92 metastatic nodules underwent dualphase (arterial and portal) helical CT scan and Mn-DPDP MRI prior to surgery. The indication of MRI was presence or suspected of having metastatic lesions at CT scan and/or increased serum carcinoembryonic antigen (CEA) levels (10 ng/mL or more). The diagnosis was established by the combination of findings at surgery, intraoperative ultrasonography, and histopathologic examination. Two radiologists interpreted CT, MRI, and combination of CT-MRI at discrete sessions and evaluated each lesion for location, size, and intrinsic characteristics. The lesions were divided into three groups according to their diameter; 1cm<, 1-2 cm, and >2 cm. Diagnostic accuracy was evaluated using the alternative-free response receiver operating characteristic method. Detection and false positive rate were also evaluated. Results : In the lesions smaller than 1 cm, detection rate of combined CT-MRI was superior to CT or MRI alone (82%, p=0.036). The mean accuracy (Az values) of combined CT and MRI was significantly higher than that of CT in the lesions smaller than 2 cm (1 cm<, p=0.034; 1-2 cm, p=0.045). However, there was no significant difference between MRI and combined CT-MRI. The false positive rate of CT was higher than those of combined CT-MR in the lesions smaller than 1 cm (28%, p=0.023). Conclusion : Additional MRI using Mn-DPDP besides routine CT scan was helpful in differentiating the hepatic lesions (<2 cm) and could improve detection of the small hepatic metastases (<1 cm) from colorectal carcinoma.

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The relationship between biofeedback and the activation of the auditory cortex

  • 윤효운;김경환;송명성;정준영;임동미;조은미;박현욱
    • Proceedings of the KSMRM Conference
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    • pp.95-95
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    • 2003
  • We aimed to control the sensory input in terms of auditory perception. For this purpose, the direct comparison of the activation at the auditory cortex between the phases of the passive and active listening was carried out.

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Effect of MRI Media Contrast on PET/MRI (PET/MRI에 있어 MRI 조영제가 PET에 미치는 영향)

  • Kim, Jae Il;Kim, In Soo;Lee, Hong Jae;Kim, Jin Eui
    • The Korean Journal of Nuclear Medicine Technology
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    • v.18 no.1
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    • pp.19-25
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    • 2014
  • Purpose: Integrated PET/MRI has been developed recently has become a lot of help to the point oncologic, neological, cardiological nuclear medicine. By using this PET/MRI, a ${\mu}-map$ is created some special MRI sequence which may be divided parts of the body for attenuation correction. However, because an MRI contrast agent is necessary in order to obtain an more MRI information, we will evaluate to see an effect of SUV on PET image that corrected attenuation by MRI with contrast agent. Materials and Methods: As PET/MRI machine, Biograph mMR (Siemens, Germany) was used. For phantom test, 1mCi $^{18}F-FDG$ was injected in cylinderical uniformity phantom, and then acquire PET data about 10 minutes with VIBE-DIXON, UTE MRI sequence image for attenuation correction. T1 weighted contrast media, 4 cc DOTAREM (GUERBET, FRANCE) was injected in a same phatnom, and then PET data, MRI data were acquired by same methodes. Using this PET, non-contrast MRI and contrast MRI, it was reconstructed attenuation correction PET image, in which we evanuated the difference of SUVs. Additionally, for let a high desity of contrast media, 500 cc 2 plastic bottles were used. We injected $^{18}F-FDG$ with 5 cc DOTAREM in first bottle. At second bottle, only $^{18}F-FDG$ was injected. and then we evaluated a SUVs reconstructed by same methods. For clinical patient study, rectal caner-pancreas cancer patients were selected. we evaluated SUVs of PET image corrected attenuastion by contrast weighted MRI and non-contrast MRI. Results: For a phantom study, although VIBE DIXON MRI signal with contrast media is 433% higher than non-contrast media MRI, the signals intensity of ${\mu}-map$, attenuation corrected PET are same together. In case of high contrast media density, image distortion is appeared on ${\mu}-map$ and PET images. For clinical a patient study, VIBE DIXON MRI signal on lesion portion is increased in 495% by using DOTAREM. But there are no significant differences at ${\mu}-map$, non AC PET, AC-PET image whether using contrast media or not. In case of whole body PET/MRI study, %diff between contras and non contrast MRAC at lung, liver, renal cortex, femoral head, myocardium, bladder, muscle are -4.32%, -2.48%, -8.05%, -3.14%, 2.30%, 1.53%, 6.49% at each other. Conclusion: In integrated PET/MRI, a segmentation ${\mu}-map$ method is used for correcting attenuation of PET signal. although MRI signal for attenuation correciton change by using contrast media, ${\mu}-map$ will not change, and then MRAC PET signal will not change too. Therefore, MRI contrast media dose not affect for attenuation correction PET. As well, not only When we make a flow of PET/MRI protocol, order of PET and MRI sequence dose not matter, but It's possible to compare PET images before and after contrast agent injection.

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