• The Korean Journal of Nuclear Medicine
• /
• v.21 no.2
• /
• pp.167-174
• /
• 1987

Among noninvasive approaches for the evaluation of left ventricular performance, radionuclide ventriculography (RVG) has been shown to be of particular values. Phase analysis, recently introduced as more objective means for evaluating the temporal sequence of systolic ventricular wall motion than cine image of RVG comprises a pixel by pixel Fourier transformation of the time activity curve of a multiple gated acquisition equilibrium blood pool study. To examine the regional wall motion of ventricles in myocardial infarctions, we evaluated the phase image and histogram constructed for each ventricle by total phase angle range and full width of half maximum (FWHM). This study consisted of 7 normal subjects and 23 subjects with acute myocardial infarction. Contrast ventriculography and coronary angiography was performed in all partients with myocardial infarction. And we compared the result of phase analysis with cine image of RVG and examined the interrelationship between phase analysis and contrast ventriculography with coronary angiography. The results were as follows; 1) The total phase angle range and FWHM of LV phase histogram in myocardial infarction ($86^{\circ}\;and\;32^{\circ}$, repectively) were wider than those in normal control ($38^{\circ}\;and\;18^{\circ}$, respectively p<0.01). 2) RV phase angle range and FWHM in patients with right coronary artery (RCA) occlusion ($79^{\circ}\;and\;37^{\circ}$, respectively) were wider than those in normal control ($39^{\circ}\;and\;18^{\circ}$, respectively p<0.001) and the patients without RCA occlusion ($52^{\circ}\;and\;19^{\circ}$, respectively p<0.01). 3) Phase analysis was more sensitive (95%) than cine image of RVG (70%) for the detection of regional wall motion abnormality of LV.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.18 no.2
• /
• pp.28-32
• /
• 2014

Purpose Patient motion during myocardial perfusion SPECT can produce images that show visual artifacts and perfusion defects. This artifacts and defects remain a significant source of unsatisfactory myocardial perfusion SPECT. Motion correction has been developed as a way to correct and detect the patient motion for reducing artifacts and defects, and each motion correction uses different algorithm. We corrected simulated motion patterns with several motion correction methods and compared those images. Materials and Methods Phantom study was performed. The anthropomorphic torso phantom was made with equal counts from patient's body and simulated defect was added in myocardium phantom for to observe the change in defect. Vertical motion was intentionally generated by moving phantom downward in a returning pattern and in a non-returning pattern throughout the acquisition. In addition, Lateral motion was generated by moving phantom upward in a returning pattern and in a non-returning pattern. The simulated motion patterns were detected and corrected similarly to no-motion pattern image and QPS score, after Motion Detection and Correction Method (MDC), stasis, Hopkins method were applied. Results In phantom study, Changes of perfusion defect were shown in the anterior wall by the simulated phantom motions, and inferior wall's defect was found in some situations. The changes derived from motion were corrected by motion correction methods, but Hopkins and Stasis method showed visual artifact, and this visual artifact did not affect to perfusion score. Conclusion It was confirmed that motion correction method is possible to reduce the motion artifact and artifactual perfusion defect, through the apply on the phantom tests. Motion Detection and Correction Method (MDC) performed better than other method with polar map image and perfusion score result.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.20 no.1
• /
• pp.24-27
• /
• 2016

Purpose In this study, we evaluated image quality of lesion in the vicinity according filling and empty bladder developing bladder phantom. Materials and Methods Bladder phantom was developed by modifying NEMA IEC body phantom. Air-balloon was described as bladder and 6 insert were set as lesion in the vicinity bladder according to distance. The images were evaluated in terms of % BV, comparison of SUV and peak count rate (Single, Random and True count). Results % BV was decreased far away from bladder. There were different for SUV about $7.8{\pm}3.8%$ between filling and empty bladder. True count rate was decreased about 38 %. Single and random count were increased about 44, 61%. Conclusion When the lesion is close to bladder, noise is increased. That's why prior to PET-CT scan, It is important to urinate. and It helps patient to get the accurate result.

• The Korean Journal of Nuclear Medicine
• /
• v.28 no.3
• /
• pp.313-316
• /
• 1994

Usually the persistence of ventricular activity in Tc-99m DTPA cisternography is deter mined using 24 hour images in our country. However, the 24 hour image is regarded as an in-sufficient data by many investigators. They prefer 48 hour image. The aim of the present study was to evaluate the feasibility and usefulness of 48 hour delayed imaging in Tc-99m DTPA cisternography. We performed 48 hour cisternography using Tc-99m DTPA in 38 patients with known hydrocephalus. 37-111 MBq (1-3mCi) of Tc-99m DTPA were injected by lumbar puncture. Anterior and both lateral Images were obtained at 2, 6, 24 and 48 hours. The classification of hydrocephalus was done at 24 and 48 hours by two independent nuclear medicine physicians. The 48 hour images were interpretable in all cases. In seven patients, the clearance of ventricular activity was noted only on 48 hours images. Therefore, their classification was changed from type W to type III. Sixteen of 38 patients were underwent shunt operations. Clinical improvement was noted in 13 patients(1/1 of type II, 3/6 of type III 8/9 of type IV). One case who showed a changing pattern from IV to IIIa showed no clinical improvement after shunt operation. In conclusion, the 48 hour delayed imaging was feasible and useful technique in Tc-99m DTPA cisternography.

• Journal of Biomedical Engineering Research
• /
• v.23 no.3
• /
• pp.253-261
• /
• 2002

A spatially adaptive falter was formulated to imrove PET image qualify and the Performance of the filter was evaluated using simulation and phantom and human PET studies. In the proposed filter. if a pixel was identified as the edge Pixel, the Pixel value was Preserved. Otherwise a Pixel was replaced by the mean of the pixel values weighted by 2:7: 2. A Pixel was identified as the edge Pixel. if it satisfies the following conditions : the number of ADs (absolute difference between center and neighborhood pixels) which is smaller than THl (($pix_max{\times}0.1/log_2(NPM)$, NPM : mean of 6 neighborhood pixels excluding minimum and maximum) is 8-k and the number of ADs which is lager than TH2 ($NPM{\times}0.1$) is k. where k : 2, 3, …, 6. The results of this study demonstrate the superior performance of the Proposed titter compared to Gaussian fitter, weight median filter and subset averaged median filter. The proposed tittering method is simple but effective in increasing uniformity and contrast with minimal degradation of spatial resolution of PET images and thus. is expected to Provide improved diagnositc quality PET images .

• Nuclear Medicine and Molecular Imaging
• /
• v.41 no.4
• /
• pp.272-279
• /
• 2007

Purpose: The aim of this study was to evaluate the discriminating nature of $^{123}I-FP-CIT$ SPECT in patients with parkinsonism. Methods: $^{123}I-FP-CIT$ SPECT images acquired from the 18 normal controls; NC ($60.4{\pm}10.0$ yr) and 237 patients with parkinsonism ($65.9{\pm}9.2$ yr) were analyzed. From spatialIy normalized images, regional counts of the caudate, putamen, and occipital lobe were obtained using region of interest method. Binding potential (BP) was calculated with the ratio of specific to nonspecific binding activity at equilibrium. Additionally, the BP ratio of putamen to caudate (PCR) and asymmetric Index (ASI) were measured. Results: BPs of NC $3.37{\pm}0.57,\; 3.10{\pm}0.41,\; 3.23{\pm}0.48$ for caudate, putamen, whole striatum, respectively) had no significant difference with those of essential tremor; ET ($3.31{\pm}0.64,\; 3.06{\pm}0.61,\; 3.14{\pm}0.63$) and Alzheimer's disease; AD (3.33 $\pm$0.60, 3.29$\pm$0.79, 3.31$\pm$0.70), but were higher than those of Parkinson's disease; PD (1.92$\pm$0.74, 1.39$\pm$0.68, 1.64$\pm$0.68), multiple system atrophy; MSA (2.36$\pm$1.07, 2.16$\pm$0.91, 2.26$\pm$0.96), and dementia with Lewy body; DLB (1.95$\pm$0.72, 1.64$\pm$0.65, 1.79$\pm$0.66)(p<0.005). PD had statisticalIy lower values of PER and higher values of ASI than those of NC (p<0.005). And PD had significantIy lower value of PCR, higher ASI and lower BP in the putamen and whole striatum than MSA (p<0.05). Conclusion: Dopamine transporter image of $^{123}I-FP-CIT$ SPECT was a good value in differential diagnosis of parkinsonism.

• The Korean Journal of Nuclear Medicine
• /
• v.28 no.2
• /
• pp.172-176
• /
• 1994

As the Tc-99m-MIBI myocardial SPECT demonstrated wide application in the diagnosis of myocardial function, the quantitative and severity-dependent information is currently re quired. In this study, we proposed a computerized method for scoring the fixed defects in terms of extent-weighted severity and for identifying the reversibility in ischemic regions. At the first stage of this method, the transverse slices were reconstructed with 0.4 Nyquist freq. and order 5 Butterworth filter. From the oblique/sagittal slices, maximal count per pixel circumferential profiles were extracted for each sector, and then stress/redist. polar maps were normalized and plotted. For reversibility, the stress polar map was subtracted from the de-layed image and positive-valued pixels were categorized into three grades. The extent-weight-ed severity scores were calculated using the assigned grades and their number of pixels. This procedure was done automatically and the reversibility and severity scores were produced for each of the coronary territories (LAD, RCA, LCX) or any combination of these. Clinical ap-plication has shown that the changes In reversibility scores after PTCA were correlated linearly with the pre PTCA scores(r>0.8) in postinfarct cases as well as in angina, and severity scores of persistent defects in stress/rest SPECT study matched to the regional ejection fraction and visual analysis of regional wall motion of gated blood pool scan(r>0.6). We conclude that the computerized severity scoring method for the analysis of myocardial SPECT could be useful in the assessment of the myocardial ischemia and fixed defect.

• Nuclear Medicine and Molecular Imaging
• /
• v.43 no.4
• /
• pp.363-365
• /
• 2009

Kikuchi's disease is a self-limiting benign disease characterized by cervical lymphadenopathy, but it can be mistaken for malignant disease, and when involved lymph nodes are unusually located, diagnosis can be more difficult. The authors report the case of a 19-year-old man with Kikuchi's disease, who had isolated intra-abdominal lymphadenopathy and increased 18-fluoro-deoxyglucose (FDG) uptake in positron emission tomography-computed tomography (PET-CT). Although its incidence is extremely rare, intra-abdominal Kikuchi's disease with increased FDG uptake in PET-CT image should be considered in the differential diagnosis when constitutional symptoms mimic those of malignant lymphoma.

• Journal of Biomedical Engineering Research
• /
• v.26 no.5
• /
• pp.283-294
• /
• 2005

The Center for Imaging Human Structures (CIH) was established in December 2002 to develop new diagnostic imaging techniques and to make them available to the greater community of biomedical and clinical researchers at Sungkyunkwan University. CIH has been involved in 5 specific activities to provide solutions for early diagnosis and improved treatment of human diseases. The five area goals include: 1) development of a digital mammography system with computer aided diagnosis (CAD); 2) development of digital radiological imaging techniques; 3) development of unified medical solutions using 3D image fusion; 4) development of multi-purpose digital endoscopy; and, 5) evaluation of new imaging systems for clinical application

• The Korean Journal of Nuclear Medicine
• /
• v.37 no.1
• /
• pp.13-23
• /
• 2003

Neurodegenerative disorders cause a variety of dementia including Alzheimer disease, frontotemporal dementia, dementia with Lewy bodies, corticobasal degeneration, progressive supranuclear palsy, and Huntington's disease. PET scan is useful for early detection and differential diagnosis of these dementing disorders. Also, it provides valuable information about clinico-anatomical correlation, allowing better understanding of function of brain. Here we discuss recent achievements PET studies regarding these dementing disorders. Future progress in PET technology, new tracers, and image analysis will play an important role in further clarifying the disease pathophysiology and brain functions.