• Investigative Magnetic Resonance Imaging
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• 제15권1호
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• pp.67-71
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• 2011

목적 : 1.5T와 3.0T MRI에서 대상회 피질, 편도체, 해마체, 도피질의 T2 이완시간 (T2)을 비교하고자 하였다. 대상 및 방법 : 건강한 12명의 자원자를 대상으로 1.5T와 3.0T에서 해마에 대해 수직으로 FLAIR와 CPMG 펄스열 영상을 같은 조건으로 획득하였다. 대상회 피질, 편도체, 해마체, 도피질에서 T2를 측정하였고, 해마와 나머지 부위의 T2 비를 1.5T와 3.0T 사이에서 비교하였다. 결과 : 1.5T에서 측정한 평균 T2는 대상회 피질, 편도체, 해마체, 도피질에서 각각 $109.5{\pm}3.1$, $117.0{\pm}7.1$, $114.7{\pm}2.4$, $111.3{\pm}2.4$, 3.0T에서 측정한 값은 각각 $99.7{\pm}3.8$, $100.7{\pm}4.3$, $97.9{\pm}3.4$, $96.2{\pm}2.0$ 이었다. 1.5T와 3.0T 사이의 T2 변화 백분율은 각각 -8.9%, -13.5%, -14.6%, -13.5% 이었다. 1.5T와 3.0T 사이에서 해마체에 대한 대상회 피질, 편도체, 도피질의 T2 비는 각각 0.96 과 1.02 (p=0.003), 1.02 과 1.03 (p > 0.05), 0.97 과 0.98 (p > 0.05) 이었다. 결론 : 3.0T에서 대상회 피질의 T2 감소는 편도체, 도피질, 해마체와 비교해서 상대적으로 적었고, 대상회 피질과 해마체의 T2 이완시간비는 1.5T와 3.0T에서 의미 있는 차이를 보였다.

• Korean Journal of Radiology
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• 제20권5호
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• pp.854-861
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• 2019

Objective: To evaluate quantitative magnetic resonance imaging (MRI) parameters for differentiation of cysts from and solid masses in the anterior mediastinum. Materials and Methods: The development dataset included 18 patients from two institutions with pathologically-proven cysts (n = 6) and solid masses (n = 12) in the anterior mediastinum. We measured the maximum diameter, normalized T1 and T2 signal intensity (nT1 and nT2), normalized apparent diffusion coefficient (nADC), and relative enhancement ratio (RER) of each lesion. RERs were obtained by non-rigid registration and subtraction of precontrast and postcontrast T1-weighted images. Differentiation criteria between cysts and solid masses were identified based on receiver operating characteristics analysis. For validation, two separate datasets were utilized: 15 patients with 8 cysts and 7 solid masses from another institution (validation dataset 1); and 11 patients with clinically diagnosed cysts stable for more than two years (validation dataset 2). Sensitivity and specificity were calculated from the validation datasets. Results: nT2, nADC, and RER significantly differed between cysts and solid masses (p = 0.032, 0.013, and < 0.001, respectively). The following criteria differentiated cysts from solid masses: RER < 26.1%; nADC > 0.63; nT2 > 0.39. In validation dataset 1, the sensitivity of the RER, nADC, and nT2 criteria was 87.5%, 100%, and 75.0%, and the specificity was 100%, 40.0%, and 57.4%, respectively. In validation dataset 2, the sensitivity of the RER, nADC, and nT2 criteria was 90.9%, 90.9%, and 72.7%, respectively. Conclusion: Quantitative MRI criteria using nT2, nADC, and particularly RER can assist differentiation of cysts from solid masses in the anterior mediastinum.

• Journal of Korean Neurosurgical Society
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• 제37권5호
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• pp.336-339
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• 2005

Objective: The goal of this study is to establish the anatomical criteria of the normal and stenotic lumbosacral extraforaminal tunnel, and also to determine the effect of the pathologic intervertebral disc on the size of extraforaminal tunnel in the lumbosacral spine. Methods: MRI and CT scans were reviewed and classified into two groups: (1) 40 patients with normal discs at L5- S1 (Group 1) and (2) 43 patients that had undergone successful decompression surgery for extraforaminal entrapment at the lumbosacral region(Group 2). In these two groups, the following parameters were compared are compared: the distance between the disc margin and the ala (lumbosacral tunnel) on the axial MRI, and the posterior disc height at L5-S1 on the mid-sagittal MRI. Results: In the group 1, the mean distance of the lumbosacral tunnel on the axial MRI was $10.1{\pm}2.2mm$. The mean posterior disc height at L5-S1 was $7.4{\pm}1.7mm$ on the mid-sagittal MRI. In the group 2, the mean distance between the disc margin and the ala (costal process) was $1.6{\pm}1.3mm$ on the axial MRI. The average posterior disc height was $4.4{\pm}1.5mm$ on the mid-sagittal MRI. The posterior disc height and the size of the lumbosacral tunnel between the two groups were statistically different on the paired t-test (p<0.0001). However, the posterior disc height was not positively correlated with the size of the extraforaminal tunnel for group 2 (p=0.909). Conclusion: The extraforaminal stenosis was correlated to pathologic disc. However, the posterior disc height was not correlated to the size of the of the extraforaminal tunnel.

• 전자공학회논문지
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• 제53권12호
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• pp.131-138
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• 2016

본 연구에서는 CT에서 사용되는 요오드화 조영제가 가돌리늄조영제와 비교하여 MR영상신호에 어떠한 영향을 미치는지 알아보고자 하였으며, 이에 따른 CT조영증강 검사 이후 MRI검사를 시행하는 프로토콜이 적정한지에 대하여 논하고자 하였다. 실험은 iodine과 gadolinium의 두 개의 팬텀을 제작하여 MRI에서의 통상적인 T1, T2, T2 FLAIR, 3D Angio 검사를 시행 후, 이에 대한 정량적 분석이 이루어졌다. 실험결과 체내 자유수(Free water)와 유사한 셀라인의 신호강도 SSI(Saline's Signal Intensity)는 iodine팬텀에서 각 175, 1231, 333, 37 [a.u]을 보였고, gadolinium팬텀에서 101, 1021, 321, 31 [a.u]을 기록하였다. 셀라인의 SI(Signal Intensity)를 기준으로 가장 큰 차이의 신호강도 BDEPS(the Biggest Difference of EPS)는 iodine팬텀에서 각 1297, 123, 757, 232 [a.u]를 보였고, gadolinium팬텀에서 793, 6, 1495, 365 [a.u]를 기록하였다. 이때 셀라인과 비교한 신호증강정도 EPS(Enhancement Percentage to Saline)는 iodine팬텀에서 641.1 -90.0, 127.3, 527%를 보였고, gadolinium팬텀에서 685.1, 99.4, 365.7, 1077.4% 기록하였다. BDEPS를 보이는 지점인 BP(BDEPS's point)는 iodine팬텀에서 900, 900, 477, 900 mmol을 보였고, gadolinium팬텀에서 4, 0.2, 0.2, 40 mmol을 기록하였다. 셀라인과 비교 하여 육안으로 SI변화를 확인할 수 있는 지점 CPSS(Change Point of SI to SSI)는 iodine팬텀에서 63, 423, 63, 29 mmol을 보였고, gadolinium팬텀에서 각 [50, 30], [4, 0.2], [4, 1], 0.2 mmol을 기록하였다. 본 연구를 통하여 iodine 역시 MR신호에 영향을 끼치며, 이는 gadolinium과는 다른 패턴을 보이는 것을 확인하였다. 이에 따라 임상현장에서 본 연구의 정량화 데이터를 감안하여 CT와 MRI 검사 순서 프로토콜을 결정한다면 유용한 진단학적 MR영상을 구현 할 수 있을 것으로 사료된다.

• Investigative Magnetic Resonance Imaging
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• 제14권2호
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• pp.121-125
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• 2010

목적 : 본 연구는 유방암 진단 후 추가적으로 유방암을 발견하는 데 있어 3 테슬러 유방자기공명 영상의 진단적 정확성을 알아보고자 하였다. 대상 및 방법 : 2009년 3월부터 6월까지, 새롭게 유방암을 진단 받은 101명의 환자가 유방 자기공명 영상을 촬영하고 수술을 받았다. 자기공명영상에서는 종양의 범위와 다초점, 다중심, 반대측 유방암이 의심되는 소견에 대해 분석하였다. 자기공명영상으로 발견된 유방암은 조직검사나 위치결정술 후 수술로 진단되었다. 결과 : 34명 환자에서 37예의 암이 의심되는 소견이 추가적으로 자기공명영상에서 보였다. 16예의 다초점 유방암, 11예의 다중심 유방암 그리고 2예의 반대측 유방암을 포함하여 29예가 진양성이었다(29/37, 78.4%); 13 (44.8%)예는 관내상피암 그리고 16 (55.1%)예는 침윤성 암이었다. 6예의 양성 병변, 2예의 고위험병변을 포함하여 8예가 위양성이었다(8/37, 21.6%). 결론 : 3 테슬러 자기공명영상에서 최근에 유방암이 진단된 환자의 33.7%에서 추가적으로 암이 의심되는 소견이 보였다. 추가적으로 유방암을 발견하는 3 테슬러 자기공명영상의 민감도와 특이도는 각각 100%, 89.3% 였다

• Korean Journal of Radiology
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• 제20권5호
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• pp.812-822
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• 2019

Objective: To assess the diagnostic value of combining diffusion-weighted imaging (DWI) with conventional magnetic resonance imaging (MRI) for differentiating between pathologic and traumatic fractures at extremities from metastasis. Materials and Methods: Institutional Review Board approved this retrospective study and informed consent was waived. This study included 49 patients each with pathologic and traumatic fractures at extremities. The patients underwent conventional MRI combined with DWI. For qualitative analysis, two radiologists (R1 and R2) independently reviewed three imaging sets with a crossover design using a 5-point scale and a 3-scale confidence level: DWI plus non-enhanced MRI (NEMR; DW set), NEMR plus contrast-enhanced fat-saturated T1-weighted imaging (CEFST1; CE set), and DWI plus NEMR plus CEFST1 (combined set). McNemar's test was used to compare the diagnostic performances among three sets and perform subgroup analyses (single vs. multiple bone abnormality, absence/presence of extra-osseous mass, and bone enhancement at fracture margin). Results: Compared to the CE set, the combined set showed improved diagnostic accuracy (R1, 84.7 vs. 95.9%; R2, 91.8 vs. 95.9%, p < 0.05) and specificity (R1, 71.4% vs. 93.9%, p < 0.005; R2, 85.7% vs. 98%, p = 0.07), with no difference in sensitivities (p > 0.05). In cases of absent extra-osseous soft tissue mass and present fracture site enhancement, the combined set showed improved accuracy (R1, 82.9-84.4% vs. 95.6-96.3%, p < 0.05; R2, 90.2-91.1% vs. 95.1-95.6%, p < 0.05) and specificity (R1, 68.3-72.9% vs. 92.7-95.8%, p < 0.005; R2, 83.0-85.4% vs. 97.6-98.0%, p = 0.07). Conclusion: Combining DWI with conventional MRI improved the diagnostic accuracy and specificity while retaining sensitivity for differentiating between pathologic and traumatic fractures from metastasis at extremities.

• 대한방사선기술학회지:방사선기술과학
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• 제41권6호
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• pp.553-560
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• 2018

PET-CT and PET-MRI which integrates CT using ionized radiation and MRI using phenomena of magnetic resonance are determined to have the limitation to apply the semi-quantitative index, standardized uptake value (SUV), with the same level due to the fundamental differences of image capturing principle and reorganization, hence, their correlations were analyzed to provide their clinical information. To 30 study subjects maintaining pre-treatment, $^{18}F-FDG$ (5.18 MBq/㎏) was injected and they were scanned continuously without delaying time using $Biograph^{TM}$ mMR 3T (Siemens, Munich) and Biograph mCT 64 (Siemens, Germany), which is an integral type, under the optimized condition except the structural differences of both scanners. Upon the measurement results of $SUV_{max}$ setting volume region of interest with evenly distributed radioactive pharmaceuticals by captured images, $SUV_{max}$ mean values of PET-CT and PET-MRI were $2.94{\pm}0.55$ and $2.45{\pm}0.52$, respectively, and the value of PET-MRI was measured lower by $-20.85{\pm}7.26%$ than that of PET-CT. Also, there was a statistically significant difference in SUVs between two scanners (P<0.001), hence, SUV of PET-CT and PET-MRI cannot express the clinical meanings in the same level. Therefore, in case of the patients who undergo cross follow-up tests with PET-CT and PET-MRI, diagnostic information should be analyzed considering the conditions of SUV differences in both scanners.

• Korean Journal of Radiology
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• 제22권7호
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• pp.1021-1033
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• 2021

Objective: To assess the expression of vascular normalization genes in different molecular subtypes of breast cancer and to determine whether molecular subtypes with a higher vascular normalization gene expression can be identified using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI). Materials and Methods: This prospective study evaluated 306 female (mean age ± standard deviation, 50 ± 10 years), recruited between January 2014 and August 2017, who had de novo breast cancer larger than 1 cm in diameter (308 tumors). DCE MRI followed by IVIM DWI studies using 11 different b-values (0 to 1200 s/mm²) were performed on a 1.5T MRI system. The Tofts model and segmented biexponential IVIM analysis were used. For each tumor, the molecular subtype (according to six [I-VI] subtypes and PAM50 subtypes), expression profile of genes for vascular normalization, pericytes, and normal vascular signatures were determined using freshly frozen tissue. Statistical associations between imaging parameters and molecular subtypes were examined using logistic regression or linear regression with a significance level of p = 0.05. Results: Breast cancer subtypes III and VI and PAM50 subtypes luminal A and normal-like exhibited a higher expression of genes for vascular normalization, pericyte markers, and normal vessel function signature (p < 0.001 for all) compared to other subtypes. Subtypes III and VI and PAM50 subtypes luminal A and normal-like, versus the remaining subtypes, showed significant associations with K^trans, k_ep, v_p, and IAUGC_BN90 on DEC MRI, with relatively smaller values in the former. The subtype grouping was significantly associated with D, with relatively less restricted diffusion in subtypes III and VI and PAM50 subtypes luminal A and normal-like. Conclusion: DCE MRI and IVIM parameters may identify molecular subtypes of breast cancers with a different vascular normalization gene expression.

• Investigative Magnetic Resonance Imaging
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• 제20권4호
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• pp.224-230
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• 2016

Purpose: The purpose of this study was to compare the grade of fatty degeneration and atrophy of rotator cuffs on immediate postoperative MRI to those on preoperative MRI in patients with rotator cuff tears. Materials and Methods: Seventy patients were included in this study, who received arthroscopic rotator-cuff repair and underwent both preoperative magnetic resonance imaging (MRI) and immediate postoperative MRI in our institution. Fatty degeneration of rotator cuffs and the atrophy of supraspinatus muscles were evaluated with T1 oblique sagittal images in the Y-shaped view. Fatty degeneration was evaluated using a Goutallier classification system, and the atrophy of supraspinatus muscles was evaluated using a modified tangent sign and a visual occupation ratio. Results: From 70 patients, a total of 100 tendons were repaired: 18, 69, and 13 tendons were treated for subscapularis, supraspinatus, and infraspinatus, respectively. The Goutallier grades (P = 0.012), modified tangent signs (P = 0.000), and visual occupation ratios (P = 0.000) of supraspinatus muscles were significantly decreased in immediate postoperative MRIs when compared to preoperative MRIs. In immediate postoperative MRIs, the Goutallier grades of supraspinatus muscles were decreased by one grade in 18.8% (n = 13) of the patients, and the atrophy of supraspinatus muscles was improved by one grade in 26.1% (n = 18) for modified tangent signs and 21.7% (n = 15) for visual occupation ratios. However, fatty infiltration by the Goutallier grades of subscapularis (P = 1.000) and infraspinatus (P = 0.157) muscles were not significantly changed after arthroscopic surgery. Conclusion: Immediate postoperative MRIs showed a significant improvement of fatty degeneration and muscle atrophy in supraspinatus muscles when compared to preoperative MRIs.

• Journal of Korean Neurosurgical Society
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• 제64권6호
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• pp.901-912
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• 2021

Objective : In the cervical spine, many surgical procedures have been developed to achieve optimal results for various disorders, including degenerative diseases, traumatic injury, and tumor. In this study, we report our experience and follow-up results with a new surgical technique for cervical spine entitled posterior floating laminotomy (PFL) in comparison with conventional laminectomy and fusion (LF). Methods : Data for 85 patients who underwent conventional LF (n=66) or PFL (n=19) for cervical spine disorders between 2012 and 2019 were analyzed. Radiological parameters, including cervical lordosis (CL), T1 slope (T1S), segmental lordosis (SL), and C2-7 sagittal vertical axis (SVA), were measured with lateral spine X-rays. Functional outcomes, comprising the modified Japanese Orthopaedic Association (mJOA), neck disability index (NDI), and visual analog scale (VAS) scores, were also measured. For the patients who underwent PFL, postoperative magnetic resonance image (MRI) was performed in a month after the surgery, and the degree of decompression was evaluated at the T2-weighted axial image, and postoperative computed tomography (CT) was conducted immediately and 1 year after the operation to evaluate the gutter fusion. Results : There was no difference in CL, T1S, SL, and C2-7 SVA between the groups but there was a difference in the preoperative and postoperative SL angles. The mean difference in the preoperative SL angle compared with that at the last follow-up was -0.3° after conventional LF and 4.7° after PFL (p=0.04), respectively. mJOA, NDI, and VAS scores showed significant improvements (p<0.05) during follow-up in both groups. In the PFL group, postoperative MRI showed sufficient decompression and postoperative CT revealed gutter fusion at 1 year after the operation. Conclusion : PFL is a safe surgical method which can preserve postoperative CL and achieve good clinical outcomes.