The Implementation of the Moral Education Program in a Medical School Using Dilemma Discussion / 한국의학교육

Gachon Medical School has developed and implemented a medical ethics course entitled, "Life and Society II". The course uses dilemma discussion based on medical case studies to allow students to develop their moral reasoning ability in both clinical and hospital settings. The course was developed by the faculty of medicine during the 1998-1999 academic years. The program was designed in a four-stage process: 1) learning objectives were identified, 2) contemporary controversies and relevant ethical issues were chosen based on relevance to modern medical practice, 3) a syllabus was drafted based on the aforementioned ethical issues and teaching methods appropriate for each issue were integrated into the syllabus, and 4) tutorial manuals were produced. The course was taught to 41 second-year premedical students and evaluated by student surveys. The learning goals were identified through both a literature survey of contemporary issues in medical ethics and an in-house survey of important content to teach in a medical ethics course. The curriculum was designed based on the identification of specific learning objectives per ethical issue, selection of appropriate materials and content, organization of dilemma scenarios and formulation of questions for discussion. The course was taught using a variety of teaching formats: dilemma discussions, seminars, tutorials, lectures, assigned readings and student presentations. Positive results were obtained from the student surveys: it was discovered that most students thought that the course's learning objectives were achieved. Furthermore, of all the teaching methods employed, most of our students felt that discussing dilemmas was the most effective method for developing moral reasoning ability.

Clinical Features Associated with an Increased Risk of Malignancy in Indeterminate Group by Find Needle Aspiration of Thyroid Nodules / 대한내분비학회지

BACKGROUND: The recommended management of patients who have cytologic diagnosis of indeterminate group by fine fine needle aspiration (FNA) in thyroid nodules is controversial. Our objective was to identify the incidence of malignancy through thyroidectomy in indeterminate group and clinical features associated with an increased risk of malignancy that might guide future practice. METHODS: We retrospectively reviewed the medical records of 222 patients who had cytologic diagnosis of indeterminate group by FNA in thyroid nodules at Seoul National University Hospital from Jan. 1990 to Aug. 1998. Patients characteristics and clinical features were compared between benign and malignant nodules classified as pathologic findings through thyroidectomy. RESULTS: The frequency of indeterminate group was 6% (222/3981) among patients underwent thyroid FNA. The frequency of malignant nodules was 47.4% (64/135) among 135 patients underwent thyroidectomy. Among clinical features, rapid increase in size (7.0% vs 20.3%, p=0.024), local symptoms such as dysphagia, hoarseness, pain (1.4% vs 15.6%, p=0.003), fixation (4.4% vs 35.7%, p<0.001), hard consistency(15.7% vs 59.7%, p<0.001) and irregular surface(6.3% vs 25.6%, p=0.001) were significantly more common in malignant nodules than in benign nodules. However, clinical features such as mean age of patients, male sex, presence of past history of benign thyroid disease, family history of benign thyroid disease, solitary nodule, presence of cervical lymph nodes, mean size of nodules and cold nodules by thyroid scan in malignant nodules were not significantly different from that in benign nodules. Among clinical features that were significantly more common in malignant nodules, fixation(p=0.042) and presence of local symptoms (p=0.043) were significantly independent risk factors predictive of malignancy. CONCLUSION: Its better to recommend thyroidectomy in patients with clinical features such as presence of local symptoms, fixed nodule and hard nodule in indeterminate group, in otherwise to decide treatment with repeated FNAs when clinical features such as patients symptoms and physical examinations of nodule change through regular follow-up.

Usefulness of Immunoglobulin Fraction Precipitated with Polyethylene Glycol in Assay for TSH Receptor Antibodies using Chinese Hamster Overy Cells Expressing Human TSH Receptors / 대한내분비학회지

BACKGROUND: Graves' disease and primary myxedema are thought to be caused by the action of TSH receptor autoantibodies(thyroid stimulating antibody; TSAb & thyroid stimulation blocking antibody; TSBAb). Thus, detection of these antibodies is crucial in diagnosis and in follow up of those patients. Recently, a sensitive method using human TSH receptor transfected Chinese Hamster Ovary(CHO) cells has been developed. However, the complexity of IgG purification procedure is considered as a limitation for its clinical application as a routine test. The aim of this study is to determine whether polyethylene glycol(PEG)-precipitated immunogiobuIin fraction could substitute for purified IgG. METHODS: We developed optimal conditions for TSAb and TSBAb assays using crude, PEG precipitated immunoglobulin fraction; and evaluated the correlation of TSAb and TSBAb activities between thase measured using crude immunoglobulin fraction and purified IgG to clarify the usefulness of PEG-precipitated immunoglobulin fraction. TSH receptor expressing wild type CHO cells were used in TSAb and CHO cells expressing chimeric TSH receptor(Mc2; 90-165 amino acid residues were substituted by those of rat LH/CG receptar) were used in TSBAb assay to minimize the possible disturbing effects of TSAb in serum. RESULTS: The optimal serum amount for TSAb and TSBAb assay using PEG-precipitated immunoglobulin fraction were 250mL serum equivalent/well and 50mL serum equivalent/well, respectively. The optimal incubation time for both assays were 2 homs, and aptimal ccrncentration of bTSH for TSBAb assay was 0.1U/L. TSAb activities measured with PEG-precipitated immunoglobulin were significantly correlated with those measured with purified IgG in 26 patients with Graves diseases(r=0.93, p<0.001). Although TSBAb activities measured using PEG-precipitated imrnunoglobulin were conelated with those measured using purified IgG in 20 patients with primary myxedema(r=0.86, p<0.001), the positive rate in TSBAb assay using PEG-precipitated immunoglobulin was lower than that of usmg purified IgG(20% v.s. 65%) because of negative conversion of TSBAb activities in samples with weakly positive TSBAb activities measured using purified IgG. CONCLUSION: PEG-precipitated immunoglobulin fraction could be used instead of purified IgG in TSAb assay using hTSHR-tranasfected wild type CHO cells with equal sensitivity and specificity. This simple and practical TSAb assay using PEG-precipitated immunoglobulin in hTSHR-transfected CHO cells would be useful in clinica1 practiee.

Diagnosis of Ictal Hyperperfusion Using Subtraction Image of Ictal and Interictal Brain Perfusion SPECT / 대한핵의학회잡지

A robust algorithm to disclose and display the difference of ictal and interictal perfusion may facilitate the detection of ictal hyperfusion foci. Diagnostic performance of localizing epileptogenic zones with subtracted SPECT images was compared with the visual diagnosis using ictal and interictal SPECT, MR, or PET. Ictal and interictal Tc-99m-HMPAO cerebral perfusion SPECT images of 48 patients(pts) were processed to get parametric subtracted images. Epileptogenic foci of all pts were diagnosed by seizure free state after resection of epileptogenic zones. In subtraction SPECT, we used normalized difference ratio of pixel counts((ictal-interictal)/interictalx100%) after correcting coordinates of ictal and interictal SPECT in semi-automatized 3-dimensional fashion. We found epileptogenic zones in subtraction SPECT and compared the performance with visual diagnosis of ictal and interictal SPECT, MR and PET using post-surgical diagnosis as gold standard. The concordance of subtraction SPECT and ictal-interictal SPECT was moderately good(kappa=0.49). The sensitivity of ictal-interictal SPECT was 73% and that of subtraction SPECT 58%. Positive predictive value of ictal-interictal SPECT was 76% and that of subtraction SPECT was 64%. There was no statistical difference between sensitivity or positive predictive values of subtraction SPECT and ictal-interictal SPECT, MR or PET. Such was also the case when we divided patients into temporal lobe epilepsy and neocortical epilepsy. We conclude that subtraction SPECT we produced had equivalent diagnostic performance compared with ictal-interictal SPECT in localizing epileptogenic zones. Additional value of these subtraction SPECT in clinical interpretation of ictal and interictal SPECT should be further evaluated.

The Heterogeneity of Flow Distribution and Partition Coefficient in Myocardium Positron Emission Tomography / 대한핵의학회잡지

For estimation of regional myocardial blood flow with O-15 water PET, a few modifications considering partial volume effect based on single compartment model have been proposed. In this study, we attempted to quantify the degree of heterogeneity and to show the effect of tissue flow heterogeneity on partition coefficient(lamda) and to find the relation between perfusable tissue index(PTI) and (lamda) by computer simulation using two modified models. We simulated tissue curves for the regions with homogeous and heterogenous blood flow over a various flow range(0.2-4.0ml/g/min).Simulated heterogeneous tissue composed of 4 subregions of the same or different size of block which have different homogeneous flow and different degree of slope of distribution of blood flow. We measured the index representing heterogeneity of distribution of blood flow for each heterogeneous tissue by the constitution heterogeneity(CH). For model I, we assumed that tissue recovery coefficient (FMME) was the product of partial volume effect(FMMF) and PTI. Using model I, PTI, flow, and FMM were estimated. For model II, we assumed that partition coefficient was another variable which could represent tissue characteristics of heterogeneity of flow distribution. Using model II PTI, flow and (lamda) were estimated. For the simulated tissue with homogeneous flow, both models gave exactly the same estimates of three parameters. For the simulated tissue with heterogeneous flow distribution, in model I, flow and FMM were correctly estimated as CH was increased moderately. In model II, flow and (lamda) were decreased curvi-linearly as CH was increased. The degree of underestimation of (lamda) obtained using model II, was correlated with CH. The degree of underestimation of flow was dependent on the degree of underestimation of (lamda). PTI was somewhat overestimated and did not change according to CH. We conclude that estimated (lamda) reflect the degree of tissue heterogeneity of flow distribution. We could use the degree of underestimation of (lamda) to find the characteristic heterogeneity of tissue flow and use (lamda) to recover the underestimated flow.

Biodistribution and Metabolism of I-123 Labelled Fatty Acid ( I ) - 15-( p-iodophenyl ) pentadecanoic acid ( IPPA ) / 대한핵의학회잡지

I-123 labelled fatty acids are suitable for investigation of regional myocardial metabolism, so they are on the clinical trial. However, the precise properties of these materials are not characterized yet. We have synthesized phenylpentadecanoic acid and labeled this compound with I-123. The purpose of this study was to examine the stability, biodistribution, metabolism and SPECT imaging of [I-123]15-(p-iodophenyl)pentadecanoic acid(I-123-IPPA) that we made. The stability test of I-123-IPPA in serum of rat, mouse and human showed no free I-123 after 1 hour. In biodistribution study in mice for various time intervals after injection(5, 10, 15, 30, 60 minutes), uptake in myocardium was 14.5%ID/g(5 min), and 1.9%ID/heart(5 min), while uptake in muscles was 2.6%ID/g(5 min). Myocardium to blood ratio and myocardium to lung ratio increased for 5 min after injection and then decreased rapidly. Chromatographic data of rat blood and urine showed that little PPA was found in blood and urine 15-20 min after injection. The myocardial I-123-IPPA SPECT images of a dog with myocardial infarction showed defects similar to those of Tc-99m-MIBI and F-18-FDG. These data suggest that I-123-IPPA is quite stable in vitro and shows favorable biodistribution in mice. SPECT imaging with I-123-IPPA demonstrated infarct zone as photon defect in dog model of myocardial infarction. I-123-IPPA may be used for the evaluation of fatty acid metabolism in clinical trials in Korea.

Study of 188Re ( V ) -DMSA for Treatment of Cancer - Rediolabeling and Biodistribution / 대한핵의학회잡지

The purpose of this study was to examine the radiolabeling and biodistribution of 188Re(V)-DMSA as a therapeutic cancer radiopharmaceutical. We made a DMSA kit(NaHC03 1.5 mg, meso-2,3-dimercaptosuccinic acid 1.0 mg L(+)-ascorbic acid 0.7mg, SnCl2 2H2O 0.34 mg, pH 2.9) for labeling with 188Re. In this kit, 188ReO4- 5 mCi/2 ml added and boiled at 100 degree C for 3 hr in water bath. The final pH adjusted to 7.5 with 7% NaHCO3 solution. We checked the labelling efficacy with TLC-SG(n-butanol : acetic acid:H2O = 3 : 2 : 3) and examined the stability both in room temperature and in serum at 37 degree C. Biodistribution(l, 3, 13, 24, 48 hr) of 188Re(V)-DMSA compound was evaluated in Sarcoma 180 tumor-bearing mice. Each labeling efficiency and stability at room temperature for 48 hours was over 98% and 95%, respectely. The stability in serum were 82%(6 hr) and 85%(48 hr). Tumor uptake of 188Re(V)-DMSA in Sarcoma 180- bearing mice were 0.66+/-0.15%(1 hr), 0.51+/-0.10%(3 hr), 0.19+/-0..05%(24 hr) and 0.13+/-0.02%(48 hr). These result are consistent with those of 99mTc(V)-DMSA which were reported previously In conclusion, 188Re(V)-DMSA may be a useful therapeutic radiopharmaceutical for treating some cancers and metastatic bone lesion.

The Results of Transsphenoidal Microsurgery for Pituitary Microadenama in Cushing's Disease / 대한내과학회지

BACKGROUND: Cushing's disease is a hypercortisolic state attributable to hypersecretion of ACTH at pituitary gland Most of these diseases are due to pituitary microadenoma. Selective removal of adenoma by transsphenoidal microsurgery is the treatment of choice for Cushing's disease. We evaluated 25 cases to analyze results of transsphenoidal microsurgery and to identify prognostic factors that may predict successful outcome. METHODS: From 1989 to 1995, 25 patients were diagnosed as having Cushing's disease in Seoul National University Hospital. They were underwent pituitary microsurgery and confirmed to have pituitary microadenoma radiologically and pathologically. About these patients. retrospective evaluation was done. RESULTS: The patients consist of 21 females and 4 males and the age was ranged from 23 to 49 years. 19 patients (76%) were judged as immediate remission. The preoperative clinical, hormonal, and radiological characteristics of the remission and failure groups were similiar The patients who were immediate remission were followed from 3 months to 72 months. 3 patients had recurrences(15.8%) at 4, 8, 49 months after operation. The pre and postoperative clinical, hormonal, and radiological characteristics of the long-term remission and recurrence groups were similiar. We could not find any predictable factors of surgical outcome. CONCLUSION: The first line trearment of Cushing's disease is transsphenoidal microsurgery. However considering relative late and high rate of recurrence of Cushing's disease following curative surgery, careful longterm follow up is mandatory.

Multipe CD-ROM Title Sharing System Using By Multiple Users / 대한의료정보학회지

A method is well known to backup the necessary and useful data into CD-ROM. It is, however, difficult for multiple users to simultaneously access these CD-ROMs which are scattered. In this paper, we have developed the system of which many user can concurrently access some CD-ROMs which are scattered in several locations. The system developed in this paper can be operated under a client/sever network and in window 95 for an easily usage. The system has, now, evaluated very good in some library of university, official department, and hospital in korea. The developing of the system is, further, to extend CD-Recorder, Juke-Box, and so on.

Labeling and Biodistribution of Re-188-DTPA ( Diethylenetriaminepentaacetic acid ) / 대한핵의학회잡지

Re-188 is useful candidate for therapeutic radionuclide because it has a physical half life of 17 hours, contains beta ernissions suitable for therapy(maximum energy 2.12MeV) and emits a garnma ray that is suitable for quantitative diagnostic scanning(155keV). To use He-188 as a radionuclide compound of angioplasty balloon radiotherapy, we investigated the labelling method and biodistribution of Re-188- DTPA. We postulated that labeled Re-188-DTPA is preferable because it would be excreted via urinary system more easily than other compounds. To label Re-188 with DTI'A, 1ml of 222MBqI(6mCi) of Re-188 was added to DTPA solution(DTPA 20mg, SnC4 2HsO 10mg, pH 3.5) and boiled at 100C for 120min in water bath. pH was adjuted to 5 with 2.3Fo sodium acetate. I.abeling efficiency was measured using TLC-SG(acetone, saline). We evaluated biodistribution of Re-188-DTPA in sacrificed mice at 10 and 60 minutes after injection. We acquired images of kidneys, and drew tirne-activity r.urves in normal dogs and rats and calculated Trnax and Tl/2 in rats. The labelling efficiency was 95.7Yo on average. Labelling of Re-188-DTPA was stable(90% after 5hours) in vitro at room temperature. According to time-activity curves of dogs and rats, it took 15 to 20 minutes after injection for Re-188-DTPA to be washed out through kidneys. In conclusion, Re-188-DTPA was successfully labeled, Re-188-DTPA was stable in vitro and was excreted early via kidneys in animals. We could recornmend Re-188-DTPA as radionuclide of potential use in angioplasty balloon radiotherapy.

Clinical Application of Positron Emission Tomography / 대한핵의학회잡지

No abstract available.

Optimization of Subtraction Brain Perfusion SPECT with Basal / Acetazolamide Consecutive Acquisition / 대한핵의학회잡지

This study investigated the method to adjust acquisition time(a) and injection dose(i) to make the best basal and subtraction images in consecutive SPECT. Image quality was assumed to be mainly affected by signal to noise ratio(S/N). Basal image was subtracted from the second image consecutively acquired at the same position. We calculated S/N ratio in basal SPECT images(S1/N1) and subtraction SPECT images(Ss/Ns) to find a(time) and i(dose) to maximize S/N of both images at the same time. From phantom images, we drew the relation of image counts and a(time) and i(dose) in our system using fanbeam-high-resolution collimated triple head SPECT. Noise by imaging process depended on Poisson distribution. We took maximum tolerable duration of consecutive acquisition as 30 minutes and maximum injectible dose as 1,850MBq(50 mCi)(sum of two injections) per study. Counts of second-acquired image(S2), counts(Ss) and noise(Ns) of subtraction SPECT were as follows. C1 was the coefficient of measurement with our system.

Ablation of Remnant Thyroid Tissue with I-131 in Well Differentiated Thyroid Cancer After Surgery / 대한핵의학회잡지

To evaluate the effectiveness of I-131 in ablation of residual thyroid tissue, we analyzed 350 patients with thyroid cancer who were treated with various doses of I-131 after surgery for thyroid cancer. Two hundred fifty five patients were treated with l.lGBq(30mCi) of I-131 for ablation of remnant thyroid and one hundred seventeen patients received more than 2.8GBq(75mCi) of I-131. We determined the effectiveness of ablation by following I-131 whole body scan. Absent visible uptake or minimal uptake in thyroid tissue were considered as successful ablation. Of 255 patients who received doses of 30mCi I-131 therapy, 131 patients(51%) showed successful ablation of residual thyroid tissue with 2.6+/-1.7 times of I-131 therapy. Of 117 patients who received doses of the more than 75mCi I-131, 84 patients(72%) had successful remnant thyroid ablation with 1.6+/-1.1 times of I-131 therapy. According to the extent of surgery, successful ablation rates were 78%, 62%, 54%, 33% in patients who underwent total thyroidectomy, subtotal thyroidectomy, lobectomy and isthmectomy, lobectomy or tumorectomy, respectively. This study showed that ablation of remnant thyroid after surgery with 30mCi I-131 was successful only in 50%. Therefore, in cases of patients with high risk for recurrence, we recommend high dose I-131 for ablation of remnant after total thyroidectomy.

The Usefulness of F-18 FDG Whole Body PET in the Evaluation of Postoperative Recurrence of Cancer / 대한핵의학회잡지

he purpose of this study was to evaluate the usefulness of whole body F-18 FDG PET scan for deceting postoperative recurrence of cancer. One hundred four cancer patients after operation were enrolled(l4 brain tumor, 15 head and neck cancer, 23 gynecologic cancer). Besides conventional images(CI) including CT and MRI, F-18 FDG PET scan was obtained on ECAT EXACT 47 scanner(Siemens-CTI), beginning 60 minutes after injection of 370MBq(10mCi) of F-18 FDG. Regional scan was also obtained with emission image. Transmission images using Ge-68 were carried out for attenuation correction in both whole body and regional images. Findings of PET and CI were confirmed by pathology or clinical follow up. The sensitivity and specificity of PET for detecting recurrence were 94% and 92%, respectively. Contrarily, the sensitivity and specific it of CI were 78% and 68% CI results were negative and PET results were positive in 11 cases. The biopsy or clinical follow-up of those cases confirmed recurrence of tumor. False negative cases of CI were frequent in patients with gynecologic cancers. Also we measured the Serum concentration of tumor markers in patients with gynecologic cancer(CA125), thyroid cancer(thyroglobulin), and colorectal cancer(CEA). The sensitivity and specificity of tumor markers were 71% and 84%, respectively. We conclude that F-18 FDG PET can be used valuably in detecting recurrent foci of a wide variety of malignancy compared to conventional diagnositic methods.

Characteristics of 18F fluorodeoxyglucose Uptake in Human Colon Cancer Cells / 대한핵의학회잡지

Cancer tissues are characterized by increased glucose uptake. 18F-fluorodeoxyglucose(FDG), a glucose analogue is used for the diagnosis of cancer in PET studies. This study was aimed to compare the glucose uptake and glucose transporter l(GLUT1) expression in various human colon cancer cells. We measured FDG uptake by cell retention study and expression of GLUTI using Western blotting. Human colon cancer cells, SNU-C2A, SNU-C4 and SNU-C5, were used. The cells were incubated with 1micro Ci/ml of FDG in HEPES-buffered saline for one hour. The FDG uptake of SNU-C2A,SNU-C4 and SNU-C5 were 16.8+/-1.36, 12.3+/-5.55 and 61.0+/-2.17cpm/microgram of protein, respectively. Dose-response and time-course studies represent that FDG uptake of cancer cells were dose dependent and time dependent. The rate of FDG uptake of SNU-C2A, SNU-C4 and SNU-C5 were 0.29+/-0.03, 0.21+/-0.09 and 1.07+/-0.07cpm/min/microgram of protein, respectively. Western blot analysis showed that the GLUT1 expression of SNU-C5 was significantly higher than those of SNU-C2A and SNU-C4. These results represent that FDG uptake into human colon cancer cells are different from each other. In addition, FDG uptake and expression of CLUT1 are closely related in human colon cancer cells.

Analysis of Aggravated Perfusion in Myocardial SPECT after Coronary Artery Bypass Surgery / 대한핵의학회잡지

Though myocardial perfusion was usually expected to improve after coronary artery bypass graft(CABG) surgery, some myocardial segments were aggravated after operation, as we compared perfusion changes on postoperative SPECT with preoperative ones. In this study, we evaluated perfusion changes after operation in rest and stress myocardial SPCET in 44 patients (M:F=25:19, age 57.1 year +/- 8.2) who had CABG before and 3 months after operation. We tried to find out possible causes for perfusion aggravation with multivariate logistic regression analysis regarding whether bypass graft was artery or vein and which coronary artery territory was operated. Among 616 myocardial segments which were operated, 89(14.4%) aggravated after operation In the univariate analysis, myocardial segments in the left circumflex arteries(I Cx) aggravated more often(p<0.01) than others and segments having operative angioplasty did less often(p<0.01). Multivariate logistic regression revealedthat LCx was risk factor for perfusion aggravation [odds ratio=2.54 (95% confidence interval : 1.53-4.22, p<0.01)] However, this was not the case when we analysed in terms of arterial territories. Among 106 coronary rterial territories which were operated. 27(25.5%) aggravated. The territories having aggravated had similar characterstics regarding whether they received arterial or venous grafts. Angioplasty and whether the operated territories were left anterior descending. Right coronary or left circumflex arteries. In conclusion, myocardial segments in the left circumflex artery tended to aggravate more often after bypass surgery than the others. In short-term comparison of perfusion after surgery. We could not find any tendency that arterial or venous fraft was associated with more frequency of the affravation of perfusion after operation.

Predictive Values of Gated Myocardial SPECT for Wall Motion Improvement After Bypass Surgery / 대한핵의학회잡지

We studied to investigate the predictive values of gated SPECT for the improvement of wall motion after bypass surgery. As we compared postoperative SPECT with preoperative ones, we defined viability as wall motion improvement. We performed rest 71-201/stress Tc-99m-MIBI gated SPECT in 25 patients before and 3 months after bypass surgery. Myocardial wall motion was graded as normal, hypokinesia, akinesia, and dyskinesia by pair-wise visual analysis of gated pre and postoperative SPECT's on the same monitor screen. Myocardial wall thickening was determined good or poor Among 92 segments with wall motion abnormalities before operation, 69 (75%) improved and 23 did not. Before operation, we could find segments with good systolic thickening in 64 segments among total 92. Thickening of the remaining 28 was poor. Wall motion improved postoperatively in 45 segments (70%) among 64 with good thickening. Twenty four(86%) among 28 segments with poor thickening had also improved. We grouped segments into mild(hypokinetic) and severe(akinetic/dyskinetic) ones. Among 33 segments with severe motion abnormalities, 14 had good thickening and 19 did not. Nine(60%) improved out of 14 segments having severe abnormality with good thickening. However, 16(84%) segments out of 19 having severe abnormality with poor thickening also improved. Neither degree of perfusion decrease nor severity of wall motion abnormalities could explain the high rate of false negatives. In conclusion, as we defined viability as wall motion improvement by comparing pre and postoperative SPECT, systolic thickening observed by gated Tc-99m-MIBI SPECT in myocardial segments with wall motion abnormalities predicted wall motion improvement after bypass surgery. However, poor thickening could not be referred as evidence of nonviable myocardium both in mild and severe contractile dysfunction, so that we might need stimulation study such as dobutamine echocardiography or dobutamine gated SPECT.

Performance of Gated Myocardial Perfusion SPECT to Diagnose Coronary Artery Disease / 대한핵의학회잡지

We studied to investigate the predictive values of gated SPECT for the improvement of wall motion after bypass surgery. As we compared postoperative SPECT with preoperative ones, we defined viability as wall motion improvement. We performed rest T1-20l/stress Tc-99m-MIBI gated SPECT in 25 patients before and 3 months after bypass surgery. Myocardial wall motion was graded as normal, hypokinesia, a kinesia, and dyskinesia by pair-wise visual analysis of gated pre and postoperative SPECT's on the same monitor wall motion abnormalities before operation, 69 (75%) improved and 23 did not. Before operation, we could find segments with good systolic thickenining 64 segments among total 92. Thickening of the remaining 28 was poor. Wall motion improved postoperatively in 45 segments (70%) among 64 with good thickening, Twenty four(86%) among 28 segments with poor thickening had also improved. We grouped segments into mild(hypokinetic) and severe(akinetic/dyskinetic) ones. Among 33 segments with severe motion abnormalities, 14 had good thickening and 19 did not. Nine(60%) improved out of 14 segments having severe abnormality with good thickening. However, 16(84%) segments out of 19 having severe abnormality with poor thickening also improved. Neither degree of perfusion decrease nor severity of wall motion abnormalities could explain the high rate of false negatives. In conclusion, as we defined viability as wall motion improvement by comparing pre and postoperative SPECT, systolic thickening observed by gated Tc-99m-MIBI SPECT in myocardial segments with wall motion abnormalities predicted wall motion improvement after bypass surgery. However, poor thickening could not be referred as evidence of nonviable myocardium both in mild and severe contractile dysfunction, so that we might need stimulation study such as dobutamine echocardiography or dobutamine gated SPECT.

Transient Prolonged Stunning by Dipyridamole Stress Proved by Post-stress ( 1 hour ) and 24 hour Tc-99m-MIBI Gated SPECT / 대한핵의학회잡지

We performed 1st day Tc-99m-sestamibi gated SPECT with dipyridamole/rest T1-201 SPECT and 2nd day 24 hour delay T1-201 SPECT/rest Tc-99m-sestamibi gated SPECT in 27 patients with coronary artery disease(24) or having chest pain(3). Stress and rest Tc-99m- sestamibi gated SPECT was acquired at 60min post-injection. A 4-point scoring system(0 to 3 for normal to absent tracer uptake) for 17 segments was used. Wall motion was scored on another 4 point scale(0 to 3 for normal to dyskinesia) in the lst day post-stress gated and the 2nd day rest gated SPECT. Post-stress gated SPECT showed wall motion abnormality in 94 segments(20%). Fifty-five segments among these 94 showed the same wall motion between post-stress and rest gated SPECT:i.e. 1-1: 23 segments, 2-2: 29 segments, 3-3: 3 segments. Re-maining 39 segments (41.5%) showed different wall motion between post-stress and rest Tc-99m-sestamibi gated SFECT. Twenty one segments with wall motion abnormality had normal perfusion(rest:15 segments, 24 hour delay: 6 segments) at either rest or 24 hour delay. Fifteen among these 21 segments showed persistent post-stress and the 2nd day rest wall motion abnormality(persistent stunning). However, in 6 segments with prolonged (1 hour after stress) stunning, abnormal wall motion did improve in the 2nd day rest Tc-99m-sestamibi gated SPECT(transient prolonged stunning). These 6 segments had normal perfusion at rest(n=4) or at 24 hour delay(n=2). Post stress wall motions showed significantly higher scores in persistent stunning than in prolonged transient stunning(P value<0.05). It was concluded that we could find stunned myocardium with gated Tc-99m-sestamibi SPECT at either post-stress or rest and that some myocardial walls of post-stress 1 hour gated SPECT did not show truly rest wall motion. So, we should be cautious if we use post-stress Tc-99m-sestamibi wall motion to assess rest wall motion.

Bone Scan Appearance of Renal Osteodystrophy in Diabetic Chronic Renal Failure Patients / 대한내과학회지

OBJECTIVES: It is suggested that frequency of low turnover bone disease is much higher in diabetic renal osteodystrophy. We tried to find out whether bone scan images show less 99mTc-MDP uptake in diabetic renal ostwdystrophy. METHODS: We compared bone scan images of renal failure patients with and without diabetes. The number of patients studied was 134 (43 patients had diabetes and 91 patients did not). Two experienced nuclear physicians read Tc-99m-MDP bone scan twice separately and gave the score either 1 or 0 on 6 areas; axial skeleton, long bone, skull and mandible, periarticular areas, costochondral junction and sternum. The means of summed scores were compared using Students t-test. To exclude the effects of sex, age and serum creatinine concentration, we analysed these factors together with the effect of diabetes using analysis of covariance. We also interpreted on bone scan images, as classical renal osteodystrophy, renal failure and normal. RESULTS: The intra- and interobserver variations were very low. Patients of diabetes group showed significantly lower mean of summed score(2.0+/-0.95) compared to patients of non-DM group(3.3+/-1.2). Analysis of covariance revealed that lower score of diabetes group was independent of sex, age and serum creatinine level. of diabetes group, 2 nuclear physicians interpreted bone scans as classical renal osteodystrophy in 60% and 56%, However, they interpreted bone scans of non-DM group in 80%, 88%(between-observer k: 0.74). Chi-square test showed that this difference was statistically significant (p<0.05). CONCLUSION: Bone scan image of diabetic renal osteodystrophy showed less 99mTc-MDP uptake, which meant low osteoblastic activity. This influence of diabetes upon bone uptake was significant after considering other confounding factors.