PURPOSE: The aim of this study was to evaluate whether T1-201 reinjection distinguishes viable from non-viable myocardium in patients with reverse redistribution after acute myocardial infarction. MATERIALS AND METHODS: We studied 42 patients with acute myocardial infarction (age, 55+/-12 years). Eighteen (43%) out of 42 showed reverse redistribution on dipyridamole stress-4 hour redistribution T1-201 single photon emission computed tomography (SPECT). T1-201 reinjection was performed at 24 hours. Reverse redistribution was defined as worsening of perfusion defect at 4 hour delayed scan. All patients underwent follow-up echocardiography in 4 months to assess regional wall motion improvement. T1-201 uptake on reinjection images were analyzed for the prediction of myocardial wall motion improvement. RESULTS: Of 36 segments with reverse redistribution, 17 segments showed normal wall motion on echocardiography, while 19 segments showed all motion abnormalities. Of 19 the segments with reverse redistribution, 11 (58%) showed enhanced uptake after 24 hour reinjection. Myocardial wall motion was improved in 10 of 11 segments (90%) with enhanced uptake on reinjection. Wall motion improvement was not seen in 5 of 8 segments (63%) without enhanced thallium uptake. When myocardial viability was assessed by the uptake on reinjection image, nine of 10 segments (90%) with normal or mildly decreased uptake showed improved wall motion. Wall motion was not improved in 5 of 9 segments (56%) with severely decreased uptake. CONCLUSION: In patients with acute myocardial ifarction, T1-201 reinjection imaging on myocardial segments with reverse redistribution has a high positive predictive value in the assessment of myocardial viability.
Dipyridamole ; Echocardiography ; Follow-Up Studies ; Humans ; Myocardial Infarction* ; Myocardium* ; Perfusion ; Thallium* ; Tomography, Emission-Computed, Single-Photon

PURPOSE: We investigated the role of myocardial perfusion SPECT in prediction of ventricular dilatation and the role of revascularization including thrombolytic therapy and PTCA in prevention of ventricular dilatation after an acute myocardial infarction (AMI). MATERIALS AND METHODS: We performed dipyridamole stress, 4 hour redistribution, and 24 hour reinjection Tl-201 SPECT in 16 patients with AMI two to nine days after attack. Perfusion and wall motion abnormalities were quantified by perfusion index (PI) and wall motion index (WMI). Left ventricular ejection fraction (LVEF), WMI and ventricular volume were measured within 1 week of AMI and after average of 6 months. According to serial changes of left ventricular end-diastolic volume (LVEDV), patients were divided into two groups. We compared WMI, PI and LVEF between the two groups. Relationships among degree of volume, stress-rest PI, WMI, CKMB, Q wave, LVEF and revascularization were analysed using multivariate analysis. RESULTS: Only initial rest perfusion index was significantly different between the two groups (p<0.05). While initial LVEF, stress PI, CKMB, trial of revascularization procedure, presence of Q wave and WMI were not significantly different between the two groups. Eight of 16 patients (50%) showed LV dilatation on follow-up echocardiography. Three of 3 patients (100%) who did not undergo revascualrization procedure documented LV dilatation. And only 5 (38%) of the remaining 13 patients who underwent revascularization revealed LV dilatation. There was no difference in infarct location between the two groups. By multivariate linear regression analysis in patients only undergoing revascularization, rest perfusion index was the only significant factor. CONCLUSION: Myocardial perfusion SPECT performed prior to revascularization was useful in prediction of LV dilatation after an AMI. Rest perfusion index on myocardial perfusion plays as a significant predictor of left ventricular dilatation after AMI. And revascularization appears to be a valuable procedure in alleviating LV dilatation after AMI with or without viable myocardium in a limited number of patients studied retrospectively.
Dilatation ; Dipyridamole ; Echocardiography ; Follow-Up Studies ; Humans ; Linear Models ; Multivariate Analysis ; Myocardial Infarction* ; Myocardium ; Perfusion* ; Retrospective Studies ; Stroke Volume ; Thrombolytic Therapy ; Tomography, Emission-Computed, Single-Photon* ; Ventricular Remodeling*

PURPOSE: We evaluated the importance of redistribution and 24 hour reinjection images in Tl-201 SPECT assessment of myocardial viability after acute myocardial infarction (AMI). MATERIALS AND METHODS: We performed dipyridamole stress-4 hour redistribution-24 hour reinjection Tl-201 SPECT in 43 patients with recent AMI (4-16 days). The myocardium was divided into 16 segments and perfusion grade was measured visually with 4 point score from 0 to 3 (absent uptake to normal uptake). A perfusion defect with stress score 2 was considered moderate. A defect was considered severe if the stress score was 0 or l (absent uptake or severe perfusion decrease). Moderate defect on stress image were considered viable and segments with severe defect were considered viable if they showed improvement of 1 score or more on redistribution or reinjection images. We compared the results of viability assess-ment in stress-redistribution and stress-reinjection images. RESULTS: On visual analysis, 344 of 688 segments (50%) had abnormal perfusion. Fifty two (15%) had moderate perfusion defects and 292 (85%) had severe perfusion defects on stress image. Of 292 severe stress defects, 53 were irreversible on redistribution and reversible on reinjection images, and 15 were reversible on redistribution and irreversible on reinjection images. Two hundred twenty four of 292 segments (76.7%) showed concordant results on stress-redistribution and stress-reinjection images. Therefore 24 hour reinjection image changed viability status from necrotic to viable in 53 segments of 292 severe stress defect (18%). However, myocardial viability was underestimated in only 5% (15/292) of severe defects by 24 hour reinjection. CONCLUSION: The 24 hour reinjection imaging is useful in the assessment of rnyocardial viability. It is more sensitive than 4 hour redistribution imaging. However, both redistribution and reinjection images are needed since they complement each other.
Complement System Proteins ; Dipyridamole ; Humans ; Myocardial Infarction* ; Myocardium ; Perfusion ; Tomography, Emission-Computed, Single-Photon

No abstract available.
Thyroid Gland* ; Thyroid Nodule*

OBJECTIVE: The study was performed to evaluate whether thallium reinjection (RI) distinguishes viable from nonviable myocardium among myocardial segments which showed persistent perfusion defect (PD) in patients with acute myocardial infarction (AMI). MATERIALS AND METHODS: We studied 22 patients underwent PTCA after AMI. SPECT was performed in all patients using dipyridamole stress- 4 hour redistribution (RD) followed by 24 hour RI protocols. Dysfunctional segs were classified into 5 groups: 1) normal, 2) reversible, 3) mild to moderate PD, 4) severe PD and 5) reverse redistribution (RR). All patients underwent follow up echocardiography after 4 months to assess regional wall motion (WM) improvement such as a criteria of viable myocardium. RESULTS: A total of 127 segs with abnormal WM was analyzed. Of 74 segs with PD, 17 (23%) showed enhanced uptake after 24 hour RI. Five of 17 segs (29%) with PD that responded to RI with enhanced thallium uptake showed WM improvement. WM improvement were seen in the 24 of 57 segs (42%) not responding to RI. All four segs (100%) with RR that responded to RI showed improvement. WM improvement were not seen in the 5 of 8 segs (71%) with RR not responding to thallium RI. Eleven (73%) of 15 segs with mild-moderate PD after RI showed improvement, but 33% of segs with severe PD after RI did not showed improvement. Segs with mild-moderate PD after RI and fill in after RI showed improvement in comparison to segs with severe PD after RI(p<0.05). CONCLUSIONS: These data indicate that because only small proportion of PD showed further perfusion improvement after RI and predictive value by the uptake after RI was low, there was limited role of RI after myocardial infarction. Usefulness of RI could be found in segs showing RR responding to RI in AMI reflects viable myocardium.
Dipyridamole ; Echocardiography ; Follow-Up Studies ; Humans ; Myocardial Infarction* ; Myocardium ; Perfusion ; Thallium ; Tomography, Emission-Computed, Single-Photon

PURPOSE: ATP (adenosine triphosphate) is a potent coronary vasodilator with a rapid onset of action and a very short half-life. Myocardial perfusion scintigraphy with intravenous ATP has not yet been sufficiently proven in the diagnosis, follow-up, and risk stratification of coronary artery disease. The purpose of this study was to evaluate the safety, feasibility and diagnostic accuracy of pharmacologic stress thallium-201 myocardial SPECT using an intravenous ATP infusion in patients with suspected coronary artery disease. MATERIALS AND METHODS: Thalliurn-201 myocardial SPECT in 319 patients with suspected coronary artery disease were performed after the infusion of ATP (0.08 mg/kg/min for 6 rnin). The adverse effects were carefully monitored. Coronary angiography was also performed within 3 weeks. RESULTS: Although 76.5% of the patients had sorne adverse effects, they were transient, mild, and well tolerated. In all patients, the ATP infusion protocol was completed and only 2 patients required aminophylline. The adverse effects were dyspnea in 63%, headache in 31%, flushing in 21%, chest pain in 14% and abdominal discomfort in 5% of the patients. The sensitivity and specificity were 80% and 90% respectively. CONCLUSION: Thallium-201 myocardial SPECT after 6 min-infusion of ATP at a rate of 0.08 mg/kg/min is safe and has a diagnostic value in detecting coronary artery disease.
Adenosine Triphosphate* ; Aminophylline ; Chest Pain ; Coronary Angiography ; Coronary Artery Disease* ; Coronary Vessels* ; Diagnosis* ; Dyspnea ; Flushing ; Follow-Up Studies ; Half-Life ; Headache ; Humans ; Infusions, Intravenous* ; Perfusion Imaging ; Sensitivity and Specificity ; Tomography, Emission-Computed, Single-Photon*

We report four cases of spontaneous intracranial hypotension that were investigated by radionuclide cisternography Tc-99m-diethylenetriamine pentaacetic acid radionuclide cisternography of all our patients showed direct sign of cerebrospinal fluid leakage as well as indirect signs of less activity than expected over the cerebral convexities and rapid appearance of bladder activity. The headache of all patients was eventually controlled with bed rest and hydration.
Bed Rest ; Cerebrospinal Fluid ; Headache ; Humans ; Intracranial Hypotension* ; Urinary Bladder

PURPOSE: A prospective comparison was made between imaging with Tc-99m pertechnetate (Tc-99m) and Ioine-131 (I-131) for the detection of residual and metastatic tissue after total thyroidectomy in patients with well-differentiated thyroid carcinoma. MATERALS AND METHODS: Initially our patients had imaging with Tc-99m, followed by I-131 within 3 days. The study included 21 patients who had ablation with high dose of I-131 ranging from 100 mCi to 150 mCi. Planar and pinhole images were acquired for both Tc-99m and I-131. Diagnostic images of Tc-99m and I-131 were compared with post-therapy images. Degree of uptake on Tc-99m and I-131 images was scored by four point scale and compared. RESULTS: The results of the Tc-99m study were: 16 of 19 studies (84%) were positive on simple planar images, but 19 of 20 studies (95%) were positive on pinhole images. Conventional I-131 diagnostic imaging on the other hand showed that all studies (100%) were positive on both planar and pinhole images. There was a significant difference in degree of uptake between Tc-99m and I-131 planar images (p<0.05). Only one case of Tc-99m scintigraphy was negative on both planar and pinhole studies (false negative). There was no distant metastasis on the therapeutic I-131 images. CONCLUSION: Tc-99m scan using pinhole in certain clinical situations is an alternative to the I-131 scan in detecting thyroid or lymph node metastasis prior to the first ablative treatment after thyroidectomy for well-differentiated thyroid carcinoma.
Diagnostic Imaging ; Hand ; Humans ; Lymph Nodes ; Neoplasm Metastasis ; Prospective Studies ; Radionuclide Imaging* ; Sodium Pertechnetate Tc 99m* ; Thyroid Gland* ; Thyroid Neoplasms* ; Thyroidectomy

PURPOSE: The aim of this study is to demonstrate the feasibility of 2-[fluorine-18] fluoro-2-deoxy-D-glucose (F-18-FDG) whole body scan (FDG W/B Scan) using dual-head gamma camera equipped with ultra high energy collimator in patients with various cancers, and compare the RESULTS with those of coincidence imaging. MATERIALS AND METHODS: Phantom studies of planar imaging with ultra high energy and coincidence tomography (FDG CoDe PET) were performed. Fourteen patients with known or suspected maligancy were examined. F-18-FDG whole body scan was performed using dual-head gamma camera with high energy (511 keV) collimators and regional FDG CoDe PET immediately followed it. Radiological, clinical follow up and histologic RESULTS were correlated with F-18-FDG finding. RESULTS: Planar phantom study showed 13.1 mm spatial resolution at 10 cm with a sensitivity of 2638 cpm/MBq/ml. In coincidence PET, spatial resolution was 7.49 mm and sensitivity was 5351 cpm/MBq/ml. Eight out of 14 patients showed hypermetabolic sites in primary or metastatic tumors in FDG CoDe PET. The lesions showing no hypermetabolic uptake of FDG in both methods were all less than 1 cm except one lesion of 2 cm sized metastatic lymph node. The metastatic lymph nodes of positive FDG uptake were more than 1.5 cm in size or conglomerated lesions of lymph nodes less than 1 cm in size. FDG W/B scan showed similar RESULTS but had additional false positive and false negative cases. FDG W/B scan not visualize liver metastasis in one case that showed multiple metastatic sites in FDG CoDe PET. CONCLUSION:S: FDG W/B scan with specially designed collimators depicted some cancers and their metastatic sites, although it had a limitation in image quality compared to that of FDG CoDe PET. This study suggests that F-18-FDG positron imaging using dual-head gamma camera is feasible in oncology and helpful if it should be more available by regional distribution of FDG.
Electrons ; Follow-Up Studies ; Gamma Cameras* ; Humans ; Liver ; Lymph Nodes ; Neoplasm Metastasis ; Positron-Emission Tomography ; Whole Body Imaging*

In a murine model of systemic lupus erythematosus (SLE)-like chronic graft-versus-host disease (cGVHD), donor CD8+T cells rapidly fall into anergy to host cells, while donor CD4+T cells hyperactivate B cells and break B-cell tolerance to self-Ags in the recipient mouse. The functional recovery of donor CD8+T cells can result in the conversion of cGVHD to acute GVHD (aGVHD), indicating that donor CD8+T-cell anergy is a restriction factor in the development of cGVHD. In this report, we present evidence that donor CD4+CD25+regulatory T cells (T(reg) cells) are critical in maintaining the donor CD8+T-cell anergy and thus suppressing the development of aGVHD in mice that are naturally prone to cGVHD. Our results provide a novel insight into the role of T(reg) cells in determining cGVHD versus aGVHD.
T-Lymphocytes, Regulatory/*immunology ; Mice, Inbred DBA ; Mice ; Interleukin-2 Receptor alpha Subunit/*metabolism ; Immune Tolerance/physiology ; Graft vs Host Disease/*immunology ; Female ; Clonal Anergy/*physiology ; Chronic Disease ; CD8-Positive T-Lymphocytes/*immunology ; CD4-Positive T-Lymphocytes/*immunology ; Animals