• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.142-147
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• 1997

Purpose: To compare the effectiveness of the in-phase (IP) sequence and the opposed-phase (Op) sequence in the detection of focal hepatic lesions in the single breath-hold hepatic MR imaging with fast gradient T1-weighted pulse sequences. Materials and Methods: IP and OP T1-weighted breath-hold imaging was performed using fast gradient echo sequences in 45 patients referred for known focal hepatic lesions, in which 78 lesions were detected. Three blind readers independently reviewed the images for lesion detectability. The signal-to-noise ratio (SNR) of the liver, the lesion-to-liver contrast-to-noise ratio (CNR) and the liver-to-spleen CNR were also compared. A consensus was reached by three readers to determine which sequence is better in image quality. Results: On OP images, 61(78%), 61(78%), and 63(89%) lesions were correctly identified for reader 1, 2 and 3, respectively. On IP images, 66(85%), 65(83%), and 65(93%) lesions were detected for each reader, respectively. When two image sets were combined, 71(91 %), 69(88 %), and 76(97%) lesions respectively were detected for each reader. In cases of hepatocellular carcinoma, liver-to-Iesion CNR was greater on the OP images(p (0.05), but in other lesions significant difference was not demonstrated. Liver-to-spleen CNR was higher on OP images(p ( 0.1), but the SNR of the liver was higher on the IP images. Conclusion: Use of both IP and OP imaging can be helpful to avoid erroneous missing of some focal hepatic lesions.

• Investigative Magnetic Resonance Imaging
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• v.16 no.2
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• pp.173-176
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• 2012

We report the radiological findings of regional enhancement of the liver adjacent to the right adrenal pheochromocytoma. CT and MRI showed focal strong enhancement of adjacent liver tissue in the arterial phase. However during the delayed phase, the lesion showed iso-attenuation with normal hepatic parenchyma and not delineated. The lesion did not show abnormal signal intensity on neither T1 nor T2 weighted images and indistinguishable from normal parenchyma. The enhancing hepatic lesion was spontaneously regressed on postoperative follow up CT which was taken several months after the adrenalectomy.

• The Korean Journal of Nuclear Medicine
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• v.26 no.1
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• pp.106-110
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• 1992

외상, 만성간질환, 화상 및 전신성경련등의 원인으로 발생한 횡문근융해증 9예의 $^{99m}Tc-MDP$ 골스캔을 분석하여 다음과 같은 성적을 얻었다. 동통부위보다 넓은 전신성 병변이 44%에서 확인되었으며 나머지 56%는 국소 동통부위의 근육에만 Bone-seeking agent가 침착되는 것이 확인되있고, 골스캔만으로도 44%에서 신부전증이 동반되었음을 확인할 수 있었다. 전신성 병변은 원인과는 관계없이 출현하였고, 신부전증도 원인질환에는 관계없이 발생하였다. 1예에서 실시한 CT는 국소성 병변만을 보여 주었으나골스캔은 전신성 병변을 나타내어 주었다. 따라서 횡문근융해증의 진단에는 골스캔이 중요함을 확인해주었다.

• The Korean Journal of Nuclear Medicine
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• v.39 no.6
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• pp.456-463
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• 2005

Purpose: we often find variable degrees of FDG uptake and patterns in stomach, which can make difficult to distinguish physiologic uptake from pathologic uptake on FDG PET. The purpose of this study was to find out the significant findings of stomach on FDG PET. Materials and Methods: Thirty-eight patients who underwent both FDG PET and endoscopy within one week from Jun. 2003, to Aug. 2004 were included in this study. We reviewed 38 patients (18 for medical check up, 15 for work up of other malignancies, and 5 for the evaluation of stomach lesion). Their mean age was 56 years old (range:$32{\sim}79$), men and women were 28 and 10, respectively. Two nuclear physicians evaluated five parameters on FDG PET findings of stomach with a consensus: 1) visual grades 2) maximum SUV (max.SUV) 3) focal 4) diffuse and S) asymmetric patterns. We correlated the lesions of FDG PET findings of stomach with those of endoscopy. We considered more than equivocal findings on FDG PET as positive. Results: The six of 38 patients were proven as malignant lesions by endoscopic biopsy and others were inflammatory lesions (ulcer in 3, chronic atrophic gastritis in 12, uncommon forms of gastritis in 5), non-inflammatory lesions (n=3), and normal stomach (n=9). By the visual analysis, malignant lesions had higher FDG uptake than the others. The max.SUV of malignant lesions was $7.95{\pm}4.83$ which was significantly higher than the other benign lesions ($2.9{\pm}0.69$ in ulcer, $3.08{\pm}1.2$ in chronic atrophic gastritis, $3.2{\pm}1.49$ in uncommon forms of gastritis (p=0.044)). In the appearance of stomach on FDG PET, malignant lesions were shown focal (5 of 6) and benign inflammatory lesions were shown diffuse (9 of 20) and asymmetric (14 of 20). Benign lesions and normal stomach were shown variable degrees of uptake and patterns. Some cases of benign inflammatory lesions such as ulcer and gastritis were shown focal and mimicked cancerous lesion (4 of 15). Conclusion: Gastric malignant lesions had higher FDG uptake and focal pattern. However, benign inflammatory lesions had moderate degrees of uptake and diffuse and asymmetric patterns rather than focal. It is difficult to differentiate between benign lesions including normal.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.5
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• pp.960-966
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• 2017

In this paper, we proposed an algorithm that can extract lesion by inputting a medical image. Feature points are extracted using SIFT algorithm to extract genetic training of medical image. To increase the intensity of the feature points, the input image and that raining image are matched using vector similarity and the lesion is extracted. The vector similarity match can quickly lead to lesions. Since the direction vector is generated from the local feature point pair, the direction itself only shows the local feature, but it has the advantage of comparing the similarity between the other vectors existing between the two images and expanding to the global feature. The experimental results show that the lesion matching error rate is 1.02% and the processing speed is improved by about 40% compared to the case of not using the feature point intensity information.

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.135-141
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• 1997

Purpose: To assess the usefulness of breath-hold fast MR imaging of liver with fat suppression (FS) by application of chemical saturation technique in the diagnosis of regional fatty changes suspected in sonography. Materials and Methods: Thirteen patients who had focal lesions with diffuse, homogeneous signal changes after FS through chemical saturation technique without additional changes of imaging parameter during MR imaging of liver were selected. T1-weighted fast low-angle shot and T2-weighted turbo spin-echo sequences were obtained with or without FS during each single breath-holding session. Subjective changes of signal intensity between the pre-FS and the FS images were compared with the sonographic findings in each lesion. Results: Seven lesions of decreased signal intensity after FS on T1 or T2-weighted images, including three lesions only at FS T1 images, were regarded as focal fat infiltration. All seven lesions had compatible sonographic findings as homogenously echogenic areas. Another six lesions of subjectively increased signal intensity including two lesions only at FS T2 images were regarded as focal fat sparing. All six lesions had sonographic findings as homogenous echo poor areas suggesting focal fat sparing. In cases regarded as fat infiltration, score changes were more prominent at FS T1 images than FS T2 images(p=0.0002). In cases regarded as fat sparing, score changes were more prominent at FS T2 images than FS T1 images(p=0.042). Conclusion: Breath-hold fast T1 and T2-weighted MR imaging with and without chemical saturation pre-pulse may be sufficient for characterization of regional fatty changes in the differential diagnosis of focal hepatic lesion found at sonography.

• The Korean Journal of Nuclear Medicine
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• v.32 no.4
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• pp.354-364
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• 1998

Purpose: Simple X-ray study and bone scan have limitations for early diagnosis of bone or bone marrow lesions in multiple myeloma. The purpose of this study was to evaluate the diagnostic usefulness of bone marrow immunoscintigraphy using anti-granulocyte monoclonal antibody for the evaluation of bone involvement in multiple myeloma. Materials and Methods: In 22 patients (Male: 15, Female: 7) with multiple myeloma, we performed whole-body immunoscintigraphy using $^{99m}Tc$-labelled antigranulocyte antibody (BW 250/183, Scintimum $Granulozyt^{(R)}$ CIS, France) and compared the findings with those of simple bone radiography and $^{99m}Tc$-MDP bone scan. Abnormal findings in bone marrow scintigraphy were, considered to be present in case of expansion of peripheral bone marrow or focal photon defect in axial bones. Results: Marrow expansion was noted in 15 of 22 patients (68%). Focal photon defects were found in 18 patients (82%). While one (33%) of 3 patients with Stage II disease showed focal defects in bone marrow scan, abnormal focal defects were observed in 17 of 19 (90%) patients with Stage III. Among 124 focal abnormal sites which were observed in bone marrow scan, bone scan or simple bone radiography, bone marrow scan detected 92 sites (74%), whereas 82 sites (66%) were observed in simple bone radiography(58 sites, 47%) or bone scan(40 sites, 32%). Fifty-one (41%) out of 124 bone lesions were detected by bone marrow scan only, and located mostly in thoracolumbar spine. Conclusion: Bone marrow scan using $^{99m}Tc$-labelled antigranulocyte antibody seems to be a more sensitive procedure for the detection of pathologic bone lesions than simple bone X-ray or bone scan in patients with multiple myeloma.

• The Korean Journal of Nuclear Medicine
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• v.33 no.4
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• pp.368-380
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• 1999

Purpose: The purpose of this study was to evaluate and compare the scintigraphic findings and diagnostic accuracy of double-phase Tc-99m sestamibi scan in primary and secondary hyperparathyroidism (HPT). Materials and Methods: We retrospectively reviewed 16 cases of primary (18 lesions) and 11 cases of secondary HPT (44 lesions) who underwent Tc-99m-sestamibi scan before the surgical intervention. Scan was performed using LEM camera (Siemens, Germany) after the injection of 740MBq of Tc-99m sestamibi. Routine image consisted of baseline and 3-hour delayed images and each image was obtained using both parallel and pine hole collimator. The study population was 27 patients (male/female=5/22, age: $49.1{\pm}10.8$). Results: Eighteen lesions of primary HPT consisted of 13 adenomas and S hyperplasias, while all lesions of secondary HPT were hyperplasias. Among the case of primary HPT, we could detect all the lesions of 13 adenomas but only 2 lesions of 5 hyperplasias (40%) could be detected by double phase scintigraphy. Three cases of primary lesion showed decreased uptake in delayed images compared with baseline. The sensitivity, specificity, positive predictive value and accuracy of primary and secondary HPT were 58.8% (10/17), 83.3% (10/12), 83.3% (10/12), 75.9% (22/29), and 37.5% (15/40), 50% (2/4), 88.2% (15/17), 38.6% (17/44), respectively. Overall sensitivity, specificity, positive predictive value and accuracy were 43.9% (25/57), 75% (12/16), 86.2% (25/29), and 53.4% (39/73). There were no statistical difference between the weight of primary and secondary HPT lesion (p>0.05). Conclusion: Tc-99m sestamibi scan is fairly good modality to detect parathyroid lesion in patient with primary HPT before the surgical intervention. However, since some of cases may reveal decreased uptake in delayed image, a careful attention to the findings of baseline images may be helpful. Still the low accuracy of sestamibi scan in diagnosis of secondary HPT prohibits routine use of it for this disease.

• Journal of radiological science and technology
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• v.38 no.2
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• pp.115-120
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• 2015

To study the differences of focal liver lesion image detection at 3 minute, 10 minute and 15 minute time points on gadoxetic acid (GA)'s enhanced MR imaging with a flip angle (FA) of $30^{\circ}$ compared with a $11^{\circ}$. The subjects were 69 patients evaluated with GA enhanced MR imaging with 3.0T MR scanner. The patients are total 35(23 men and 7 women at the mean age of 60.4 years), hepatocellular carcinoma(23) and metastsis(12) except for normal, cyst and hemangioma. After GA was injected, FA $11^{\circ}$ and $30^{\circ}$ images were obtained at 3 minute, 10 minute and 15 minute time points respectively. After quantitative and qualitative assessment of each image was done, statistical analysis was performed by using the independent sample T-test. From both quantitative and qualitative assessment of 3 minute and 10 minute MR images after the injection of GA, FA $30^{\circ}$ images was found to be superior than FA $11^{\circ}$, but there were no statistical significance. However, at 15 minute time point, Statistically significant FA $30^{\circ}$ image(p<0.05) was better than FA $11^{\circ}$ therefore, the FA $30^{\circ}$ improves the focal liver lesion detection. FA $30^{\circ}$ of MR image can detect liver lesion more sensitively than the existing $FA11^{\circ}$ image after GA contrast enhancement at 15 minute time point.

• Investigative Magnetic Resonance Imaging
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• v.15 no.1
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• pp.22-31
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• 2011

Purpose : To compare free-breathing and respiratory-triggered diffusion-weighted imaging on 1.5-T MR system in the detection of hepatic lesions. Materials and Methods: This single-institution study was approved by our institutional review board. Forty-seven patients (mean 57.9 year; M:F = 25:22) underwent hepatic MR imaging on 1.5-T MR system using both free-breathing and respiratory-triggered diffusion-weighted imaging (DWI) at a single examination. Two radiologists retrospectively reviewed respiratory-triggered and free-breathing sets (B50, B400, B800 diffusion weighted images and ADC map) in random order with a time interval of 2 weeks. Liver SNR and lesion-to-liver CNR of DWI were calculated measuring ROI. Results : Total of 62 lesions (53 benign, 9 malignant) that included 32 cysts, 13 hemangiomas, 7 hepatocellular carcinomas (HCCs), 5 eosinophilic infiltration, 2 metastases, 1 eosinophilic abscess, focal nodular hyperplasia, and pseudolipoma of Glisson's capsule were reviewed by two reviewers. Though not reaching statistical significance, the overall lesion sensitivities were increased in respiratory-triggered DWI [reviewer1: reviewer2, 47/62(75.81%):45/62(72.58%)] than free-breathing DWI [44/62(70.97%):41/62(66.13%)]. Especially for smaller than 1 cm hepatic lesions, sensitivity of respiratory-triggered DWI [24/30(80%):21/30(70%)] was superior to free-breathing DWI [17/30(56.7%):15/30(50%)]. The diagnostic accuracy measuring the area under the ROC curve (Az value) of free-breathing and respiratory-triggered DWI was not statistically different. Liver SNR and lesion-to-liver CNR of respiratory-triggered DWI ($87.6{\pm}41.4$, $41.2{\pm}62.5$) were higher than free-breathing DWI ($38.8:{\pm}13.6$, $24.8{\pm}36.8$) (p value < 0.001, respectively). Conclusion: Respiratory-triggered diffusion-weighted MR imaging seemed to be better than free-breathing diffusion-weighted MR imaging on 1.5-T MR system for the detection of smaller than 1 cm lesions by providing high SNR and CNR.