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Yong-Ki Kim

Publications and source records attributed to Yong-Ki Kim.

13 recordsLinked to original sources
PubMed2007

Statistical parametric mapping and statistical probabilistic anatomical mapping analyses of basal/acetazolamide Tc-99m ECD brain SPECT for efficacy assessment of endovascular stent placement for middle cerebral artery stenosis.

INTRODUCTION: Statistical parametric mapping (SPM) and statistical probabilistic anatomical mapping (SPAM) were applied to basal/acetazolamide Tc-99m ECD brain perfusion SPECT images in patients with middle cerebral artery (MCA) stenosis to assess the efficacy of endovascular stenting of the MCA. METHODS: Enrolled in the study were 11 patients (8 men and 3 women, mean age 54.2 +/- 6.2 years) who had undergone endovascular stent placement for MCA stenosis. Using SPM and SPAM analyses, we compared the number of significant voxels and cerebral counts in basal and acetazolamide SPECT images before and after stenting, and assessed the perfusion changes and cerebral vascular reserve index (CVRI). RESULTS: The numbers of hypoperfusion voxels in SPECT images were decreased from 10,083 +/- 8,326 to 4,531 +/- 5,091 in basal images (P = 0.0317) and from 13,398 +/- 14,222 to 7,699 +/- 10,199 in acetazolamide images (P = 0.0142) after MCA stenting. On SPAM analysis, the increases in cerebral counts were significant in acetazolamide images (90.9 +/- 2.2 to 93.5 +/- 2.3, P = 0.0098) but not in basal images (91 +/- 2.7 to 92 +/- 2.6, P = 0.1602). The CVRI also showed a statistically significant increase from before stenting (median 0.32; 95% CI -2.19-2.37) to after stenting (median 1.59; 95% CI -0.85-4.16; P = 0.0068). CONCLUSION: This study revealed the usefulness of voxel-based analysis of basal/acetazolamide brain perfusion SPECT after MCA stent placement. This study showed that SPM and SPAM analyses of basal/acetazolamide Tc-99m brain SPECT could be used to evaluate the short-term hemodynamic efficacy of successful MCA stent placement.

Acetazolamide↗
PubMed2006

Comparison of gated blood pool SPECT and multi-detector row computed tomography for measurements of left ventricular volumes and ejection fraction in patients with atypical chest pain: validation with radionuclide ventriculography.

UNLABELLED: Gated blood pool SPECT (GBPS) is an alternative to planar radionuclide ventriculography (PRNV) and offers potential advantages. The aim of this study was to compare GBPS, multi-row detector spiral computed tomography (MDCT), and PRNV for the determination of left ventricular ejection fraction (LVEF) and left ventricular volumes (LV) in subjects with atypical chest pain. METHOD: Twenty-three consecutive patients (14 men, 9 women; mean age 56.2 +/- 9.5 years) referred for MDCT for evaluation of atypical chest pain. All patients underwent PRNV, GBPS, and MDCT at the same day. RESULTS: The mean LVEFs calculated with PRNA (57.3 +/- 8.6%), GBPS (55.2 +/- 6.6%), and MDCT (56 +/- 9.1%) were not statistically different (F value 0.3374, p = 0.715). Comparison of LVEFs from GBPS and MDCT yielded correlation coefficients of 0.5238 (p = 0.0178, 95% CI = 0.1057-0.7845). The correlation of LVEFs between GBPS and PRNV showed a correlation coefficient of 0.8073 (p < 0.0001, 95% CI = 0.5676-0.9209) and 0.6190 (p = 0.0036, 95% CI = 0.2431-0.8333) between MDCT and PRNV. The mean LV end-diastolic volume (EDV) calculated with GBPS (82.7 +/- 17.5 ml) was significantly lower than MDCT (106.8 +/- 18.5 ml) (p = 0.0001). The mean LV end-systolic volume (ESV) calculated with GBPS (37.2 +/- 9.6 ml) was also significantly lower than MDCT (48.1 +/- 15.8 ml) (p = 0.012). Comparison of EDV from GBPS and MDCT yielded a correlation coefficient of 0.5220 (p = 0.0182, 95% CI = 0.1033-0.7835). The correlation of ESV between GBPS and MDCT showed a correlation coefficient of 0.6642 (p = 0.0014, 95% CI = 0.3140-0.8553). CONCLUSION: In conclusion, the LVEF, EDV, and ESV calculated by GBPS correlated significantly with those of obtained with 16-MDCT. In addition, there were no statistical differences of LVEF calculated from PRNV, GBPS, and MDCT. However, with regard to LV, EDV and ESV from GBPS revealed statistically significantly lower than those of MDCT. Also, these results should be addressed whether similar results could also be found in patients with cardiac diseases by the consequent larger population-based study.

Algorithms↗
PubMed2006

Voxel-based statistical analysis of cerebral blood flow using Tc-99m ECD brain SPECT in patients with traumatic brain injury: group and individual analyses.

PURPOSE: Statistical parametric mapping (SPM) was applied to brain perfusion single photon emission computed tomography (SPECT) images in patients with traumatic brain injury (TBI) to investigate regional cerebral abnormalities compared to age-matched normal controls. METHOD: Thirteen patients with TBI underwent brain perfusion SPECT were included in this study (10 males, three females, mean age 39.8 +/- 18.2, range 21 - 74). SPM2 software implemented in MATLAB 5.3 was used for spatial pre-processing and analysis and to determine the quantitative differences between TBI patients and age-matched normal controls. RESULTS: Three large voxel clusters of significantly decreased cerebral blood perfusion were found in patients with TBI. The largest clusters were area including medial frontal gyrus (voxel number 3642, peak Z-value = 4.31, 4.27, p = 0.000) in both hemispheres. The second largest clusters were areas including cingulated gyrus and anterior cingulate gyrus of left hemisphere (voxel number 381, peak Z-value = 3.67, 3.62, p = 0.000). Other clusters were parahippocampal gyrus (voxel number 173, peak Z-value = 3.40, p = 0.000) and hippocampus (voxel number 173, peak Z-value = 3.23, p = 0.001) in the left hemisphere. The false discovery rate (FDR) was less than 0.04. CONCLUSION: From this study, group and individual analyses of SPM2 could clearly identify the perfusion abnormalities of brain SPECT in patients with TBI. Group analysis of SPM2 showed hypoperfusion pattern in the areas including medial frontal gyrus of both hemispheres, cingulate gyrus, anterior cingulate gyrus, parahippocampal gyrus and hippocampus in the left hemisphere compared to age-matched normal controls. Also, left parahippocampal gyrus and left hippocampus were additional hypoperfusion areas. However, these findings deserve further investigation on a larger number of patients to be performed to allow a better validation of objective SPM analysis in patients with TBI.

Adult↗
PubMed2006

Characterization of follicular thyroid nodules at fine needle aspiration biopsy using double phase thallium-201 imaging: comparison of visual and semiquantitative analyses.

OBJECTIVE: To compare visual and semiquantitative indices of double phase thallium-201 thyroid scintigraphy (DTS) for differentiation of malignant nodules by indeterminate fine needle aspiration biopsy (FNAB) results. DESIGN: DTS (early; 15 minutes; delayed, 2 hour) were performed after injection of 37MBq of thallium-201 in 60 patients with indeterminate FNAB. MAIN OUTCOME: With grade 4 and 5, sensitivity and specificity were 51.4% and 78.3%, respectively. With early lesion to nonlesion ratio (L/N) 1.49, sensitivity and specificity were 97.3% and 39.1%, respectively. With delayed L/N 1.89, sensitivity and specificity were 70.3% and 78.3%, respectively. With wash-out rate (WR) 18.93%, sensitivity and specificity were 89.2% and 82.6%. Early L/N was superior to delayed L/N and WR for the detection of malignant thyroid nodules. CONCLUSION: Visual assessment had a limited value for differentiation of follicular nodules. The optimal semiquantitative indices were 1.49 for early L/N and 1.89 for delayed L/N. Also, optimal WR was 18.93%. The early L/N was superior to delayed L/N and WR for the detection of malignant thyroid nodular lesions. However, visual assessment and early L/N of DTS showed similar results. Visual analysis and semiquantitative indices of DTS could not differentiate follicular carcinoma and follicular variant of papillary thyroid cancer.

Adenocarcinoma, Follicular↗
PubMed2005

Characterization of breast lesion using double phase Tc-99m Tetrofosmin scintimammography: comparison of visual and quantitative analyses.

UNLABELLED: To compare the diagnostic performances of visual and quantitative indices of double phase Tc-99m Tetrofosmin scintimammography (TF-SMM) for the detection of breast cancer. METHODS: Double phase TF-SMM (early, 10 min; delayed, 3h) were performed after injection of 925 MBq of Tc-99m Tetrofosmin in 75 highly suspected breast cancer patients (malignant: 49, benign: 26). For visual analysis, five scoring method was used. For quantitative analysis, early, delayed lesions to non-lesion ratios (L/Ns) and washout rate (%, WR) were calculated. Receiver operating characteristic curve (ROC) analyses were performed to determine the optimal visual grade, to calculate cut-off values of quantitative indices, and to compare visual and quantitative diagnostic performances. RESULTS: When over grade 3 of visual grade was used as cut-off value in the defection of primary breast cancer, the sensitivity and specificity were 75.5 and 80.8%, respectively. The positive and negative predictive values were 88.1 and 63.6%, respectively. The area under curve was 0.824 (95% CI, 0.719-0.902) and standard error (S.E.) was 0.047. The optimal L/N ratios were 3.13 for early and 2.56 for delayed image. When early L/N 3.13 was used as cut-off point, the sensitivity and specificity of TF-SMM were 61.2 and 96.2%, respectively. The positive and negative predictive values were 96.8 and 56.8%, respectively. The AUC was 0.809 (95% CI, 0.702-0.890) and S.E. was 0.049. When delayed L/N 2.56 was used as cut-off value, the sensitivity and specificity were 46.9 and 96.2%, respectively. The positive and negative predictive values were 95.8 and 49%, respectively. The AUC was 0.741 (95% CI, 0.627-0.835) and S.E. was 0.057. No statistical differences between visual assessment and quantitative analysis of early image (difference between area, 0.015; S.E., 0.044; 95% CI, -0.072 to 0.102; p = 0.736) and delayed image (difference between area, 0.083; S.E., 0.054; 95% CI, -0.023 to 0.060; p = 0.189) was noted. However, early L/N was superior to delayed L/N ratio for the detection of breast cancer (difference between area, 0.068; S.E., 0.033; 95% CI, 0.004-0.132; p = 0.038). CONCLUSION: In conclusion, TF-SMM showed a favorable diagnostic accuracy in differentiating benign from malignant breast lesions. The optimal visual interpretation grades for the detection of primary breast cancer of double phase TF-SMM were grade 4 and 5. The optimal quantitative indices for the detection of breast cancer were 3.12 for early L/N and 2.56 for delayed L/N. Visual and quantitative analyses showed similar results. However, early L/N was superior to delayed one for the detection of breast cancer. Therefore, the delayed image should not be routinely performed for the purpose of primary breast cancer detection. These findings deserve further investigation on a larger number of patients to be performed to allow a better validation of the differentiation malignant from benign breast lesions using double phase TF-SMM.

Breast Neoplasms↗
PubMed2005

Comparison of quantitative and visual analysis of Tc-99m MIBI scintimammography for detection of primary breast cancer.

UNLABELLED: Tc-99m MIBI scintimammography (SMM) is known to be a useful diagnostic tool for primary breast cancer. We conducted this study to compare the quantitative and visual analysis for detection of primary breast cancer and also investigated the incremental role of quantitative index of SMM. METHODS: 520 highly suspected breast cancer patients (malignant 370: palpable 232, nonpalpable 138; benign 150: palpable 67, nonpalpable 83) were included in this study. The SMM was performed 10 min after the injection of 750 MBq of Tc-99m MIBI. For visual analysis, three-scoring based method was used. The lesions to non-lesion ratios (L/Ns) were calculated. Receiver operating characteristic curve (ROC) analyses were performed to determine the optimal visual grade, to calculate cut-off value of L/N and to investigate whether the L/N could provide incremental value additive to visual analysis. The patients were divided into four groups according to the tumor size (group A: size </= 1cm; group B: 1cm < size </= 3 cm; group C: 3 cm < size </= 5 cm; group D: size > 5 cm). Also, the patients were divided into two groups according to age (under and over 45 years) to investigate incremental value of quantitative analysis. RESULTS: When visual grade 3 was used as the cut-off grade, the sensitivity and specificity were 82.7 and 78%, respectively. The L/N of malignant breast disease was significantly higher than that of benign (2.00 +/- 1.88 versus 0.60 +/- 0.7, P < 0.01). When L/N of 1.27 was used as the cut-off value, the sensitivity and specificity of SMM were 77.6 and 83.3%, respectively. When the L/N was added to visual grade, the area under curve (AUC) of visual + quantitative (V + Q) analyses was higher than that of visual (V) and quantitative (Q) analyses (AUC 0.874 versus 0.803, P < 0.01). In group A and B, the AUCs of V + Q (0.861, 0.895) were higher than those of V (0.808, 0.781) and Q (0.808, 0.813). In group C, the AUC of V + Q (0.847) was higher than that of Q (0.803, P = 0.041). However, the AUC of V (0.915) was higher than that of V + Q (P = 0.009). In group D, there were no statistical differences between V + Q (0.685) and V (0.570, P = 0.058) and Q (0.620, P = 0.145). The V + Q revealed incremental value in the detection of primary breast cancer in both age groups. Also, in older age patients group (over 45 years), the specificities of Q and V + Q were higher than younger group (under 45 years). For axillary lymph node involvement, the sensitivity, specificity, and accuracy of SMM were 66.9, 70.1, and 68%, respectively. CONCLUSION: From this study, the optimal visual grade for diagnosis of breast cancer was grade 3 and cut-off value of L/N was 1.27. Also, we found that the L/N provides incremental value additive to visual analysis. Especially, when the tumor is small (size </=3 cm), the L/N should be obtained for the diagnosis of breast cancer. The V + Q revealed incremental value in the detection of primary breast cancer in both age groups. Also, in older age patients group, the specificities of Q and V + Q were higher than younger group.

Analysis of Variance↗
PubMed2005

Normal gallbladder visualization during post-ablative iodine-131 scan of thyroid cancer.

Whole body iodine-131 scan is a well-established imaging method for the detection of metastatic or residual tumor sites in patients with well-differentiated thyroid cancer. Many false-positive iodine-131 scan findings mimicking metastatic thyroid cancer have long been reported. The authors describe a false positive uptake in normal gallbladder on post-ablative iodine-131 scan in a patient with papillary thyroid cancer. This finding should be considered to be another possible false-positive finding on iodine-131 whole body scan.

Carcinoma, Papillary↗
PubMed2004

Incremental diagnostic value of quantitative analysis of double phase Tc-99m MIBI scintimammography for the detection of primary breast cancer additive to visual analysis.

UNLABELLED: Tc-99m MIBI scintimammography (SMM) is known to be a useful diagnostic tool for primary breast cancer. We conducted this study to establish optimal visual grades for the detection of primary breast cancer and to investigate whether the quantitative indices of double phase SMM could provide incremental diagnostic value additive to visual analysis. METHODS: Five hundred and twenty highly suspected breast cancer patients (malignant: 370; benign: 150) were included in this study. Double phase Tc-99m MIBI SMM (early: 10 min; delayed: 3 h) was performed after injection of 750 MBq of Tc-99m MIBI. For visual analysis, five scoring method was used. The early and delayed lesion to non-lesion ratios (L/N) and retention index (RI) were calculated. Receiver operating characteristic curve (ROC) analyses was performed to determine the optimal visual grade, to calculate cut-off value of quantitative indices for differentiation malignant and benign diseases and to investigate whether the quantitative indices could provide incremental diagnostic value additive to visual analysis. To investigate the incremental diagnostic value of quantitative index in variable tumor size groups, the patients were subdivided into four groups (group A: size 5 cm). RESULTS: When over visual grade 3 was used as the cut-off grade for the diagnosis of breast cancer, the sensitivity and specificity were 75.5, 86.4%, respectively. Early L/N of malignant breast disease was significantly higher than that of benign (2.00 +/- 1.88 vs. 0.60 +/- 0.7; p < 0.01). However, delayed L/N and RI had no significant difference between malignant and benign breast diseases. When early L/N of 1.27 was used as the cut-off value, the sensitivity and specificity of SMM were 77.6, 83.3%, respectively. When the early L/N was added to visual grade, the area under curve (AUC) of visual + quantitative analysis (V + Q) was higher than that of visual analysis (V) alone (AUC 0.893 vs. 0.803; p < 0.01). In group A, the AUC of V + Q was higher than that of V alone (0.843 vs. 0.808; p = 0.029). In group B, the AUC of V + Q was also higher (0.913 vs. 0.781; p < 0.01). However, in groups C and D, the AUCs of V + Q and V were not different (0.926 vs. 0.915; p = 0.144: 0.663 vs. 0.570; p = 0.093). For axillary lymph node involvement, the sensitivity, specificity, and of SMM were 66.9, 70.1, and 68%, respectively. CONCLUSION: From this study, the optimal visual interpretation grades for diagnosis of breast cancer were grades 4 and 5 and cut-off value of early L/N was 1.27. Also, we found that delayed image was not required for breast cancer detection and quantitative index of early L/N provide incremental diagnostic value additive to visual analysis. Especially, when the tumor is small (size <or= 3 cm), the early L/N should be obtained for the diagnosis of breast cancer.

Breast Neoplasms↗
PubMed2003

Optimized Mueller polarimeter with liquid crystals.

We demonstrate a Mueller polarimeter in which the polarization-state generator and analyzer are both composed of a linear polarizer and two liquid-crystal variable retarders. The polarimeter is designed to optimize the accuracy of the final results by minimization of the condition numbers of the modulation and analysis matrices. The polarimeter calibration, a difficult task by conventional procedures, is achieved easily by use of the eigenvalue method of Compain et al. [Appl. Opt. 38, 3490 (1999)]. The overall polarimeter performance is tested with a linear polarizer at various angles and a compensator at various retardations.

Journal Article↗
PubMed2003

Multifocal Pott's disease (tuberculous spondylitis) incidentally detected on Tc-99m MDP bone and Ga-67 citrate scintigraphy in a patient with diabetes.

Pott's disease is an uncommon extrapulmonary form of tuberculosis. Delay in diagnosis and management may cause serious complications. The authors describe Pott's disease incidentally detected on Tc-99m MDP bone and Ga-67 imaging in a patient with diabetes. Tc-99m MDP bone scintigraphy showed intensely increased uptake in the lower cervical spine and lumbosacral regions. Ga-67 scintigraphy revealed intensely increased uptake corresponding to the areas noted on Tc-99m MDP bone scintigraphy. Magnetic resonance imaging showed destructive lesions in the C5-C6 and L5-S1 intervertebral discs with destruction of adjacent end plates. Biopsy of the lumbosacral area was guided by computed tomography, and histologic examination of the bone specimen showed caseation, giant cells, and acid-fast bacilli. Posterior decompression and posterolateral spinal fusion with bone grafts were performed. Antituberculous chemotherapy with isoniazid, rifampicin, pyrazinamide, and ethambutol was started. The patient showed remarkable relief of symptoms during a period of 9 months of therapy. Both Tc-99m MDP bone and Ga-67 imaging can offer the convenience of screening the entire body to detect multiple sites of Pott's disease.

Cervical Vertebrae↗
PubMedDate not supplied

Gated blood pool SPECT for measurement of left ventricular volumes and left ventricular ejection fraction: comparison of 8 and 16 frame gated blood pool SPECT.

UNLABELLED: Gated blood pool SPECT (GBPS) is an alternative to planar radionuclide ventriculography (PRNV) and offers potential advantages. The aim of this study was to compare 8 and 16 frame GBPS for the determination of left ventricular ejection fraction(LVEF) and left ventricular volumes (LV) in subjects underwent two consecutive GBPS. METHOD: About 66 consecutive patients (30 men, 36 women; mean age 62.3 +/- 10.4 years) referred for PRNV for evaluation of preoperative cardiac risk stratification (n = 40), prechemotherapy cardiac function evaluation (n = 18, breast cancer), and congestive heart failure patients (n = 8). All patients underwent PRNV of 16 frame and GBPS with both of 8 and 16 frame. RESULTS: The mean LVEF calculated with PRNV (58.3 +/- 16.8), showed statistically lower than 8-GBPS (70.6 +/- 17.7), and 16-GBPS (69.9 +/- 16.8) (PRNV vs. 8-GBPS, p < 0.01; PRNV vs 16-GBPS, p < 0.01; 8-GBPS vs 16-GBPS, p > 0.05). The correlation of LVEFS between 8-GBPS and 16-GBPS showed a correlation coefficient of 0.9194 (p < 0.01, 95% CI = 0.8712-0.9500). The mean left ventricular end-diastolic volumes (EDV) calculated with 8-GBPS (83.2 +/- 33.5 ml), and 16-GBPS (88.4 +/- 36.8 ml) showed no statistical differences (p > 0.05). The mean left ventricular end-systolic volumes (ESV) calculated with 8-GBPS (28.1 +/- 31.4 ml), and 16-GBPS (30.5 +/- 33 ml) showed also no statistical differences (p > 0.05). Comparison of EDV from 8 and 16-GBPS yielded a correlation coefficient of 0.7430 (p < 0.01, 95% CI = 0.6108-0.8349). The correlation between ESV of 8-GBPS and 16-GBPS showed a correlation coefficient of 0.9522 (p < 0.01, 95% CI = 0.9228-0.9705). CONCLUSION: This study demonstrated that the LVEFs of 8-GBPS correlated well with that of 16-GBPS. The LVEF of PRNV was significantly lower than those of 8 and 16-GBPS. Also, left ventricular EDV and ESV of 8-GBPS correlated well with those of 16-GBPS. Also, further studies, involving large lumber patients, should be performed to validate the usefulness of GBPS for the evaluation of left ventricular diastolic function.

Cardiac Volume↗
PubMedDate not supplied

Automatic quantification of right ventricular volumes and right ventricular ejection fraction with gated blood pool SPECT: Comparison of 8- and 16-frame gated blood pool SPECT with first-pass radionuclide angiography.

BACKGROUND: The aim of this study was to compare 8- and 16-frame gated blood pool single photon emission computed tomography (SPECT) (GBPS) for the determination of right ventricular ejection fraction (RVEF) and right ventricular (RV) volumes in subjects who underwent two consecutive GBPS studies. METHODS AND RESULTS: In this study 65 consecutive patients (29 men and 36 women) referred for first-pass radionuclide angiography (FP-RNA) underwent FP-RNA and both 8- and 16-frame GBPS. The mean FP-RNA RVEF was statistically lower than RVEF determined by 8-frame GBPS (P < .001) and 16-frame GBPS (P < .001). Comparison of RVEF by FP-RNA and GBPS yielded coefficients of 0.8666 (P < .0001) for 16-frame GBPS and 0.7290 (P < .0001) for 8-frame GBPS. The correlation of RVEF between 8- and 16-frame GBPS showed a coefficient of 0.6657 (P < .0001). The mean RV end-diastolic volume (EDV) calculated with 8- and 16-frame GBPS showed no statistical differences (P = .3580). The mean RV end-systolic volume (ESV) calculated with 8- and 16-frame GBPS also showed no statistical differences (P = .2265). Comparison of EDV by 8- and 16-frame GBPS yielded a coefficient of 0.7327 (P < .0001). The correlation between ESV by 8-frame GBPS and 16-frame GBPS showed a coefficient of 0.6067 (P < .0001). CONCLUSION: GBPS is a simple and reproducible acquisition method for the assessment of RVEF and RV volumes. RVEF values calculated by 8- and 16-frame GBPS correlated well with FP-RNA, although mean RVEF values from FP-RNA were lower than GBPS RVEF values. In addition, RV ESV and EDV were both well correlated with 8- and 16-frame GBPS. GBPS should prove to be useful in diagnosis, as well as in following disease progression and evaluating the efficacy of therapeutic interventions, in patients with biventricular dysfunction.

Cardiac Volume↗