The relationship between discrepant areas on 201TlCl/123I-BMIPP myocardial scintigraphy, local wall motion, and glucose metabolism in patients with myocardial infarction

In order to clarify the significance of the discrepancy between myocardial blood flow and fatty acid metabolism on 201TlCl/123I-BMIPP SPECT after acute myocardial infarction, we examined 52 patients (278 segments) with their first acute myocardial infarction using two-dimensional echocardiography and FDG-PET. Patients with Tl/BMIPP discrepancy in the acute stage showed higher FDG accumulation than those without Tl/BMIPP discrepancy. In the chronic stage, however, there was no significant difference between both groups. Patients with Tl/BMIPP discrepancy in the chronic stage had lower wall motion scores than those without Tl/BMIPP discrepancy. Significant improvement of the wall motion score was recognized in patients who showed Tl/BMIPP discrepancy in the acute stage. Patients were classified into stenosis and non-stenosis groups by the presence of significant stenosis on coronary angiography in the chronic stage. In the stenosis group, the Tl/BMIPP discrepancy did not show much change from the acute to chronic stage, but there was a significant decrease in the non-stenosis group. It was concluded that 201TlCl/123I-BMIPP myocardial SPECT is useful for predicting future improvement of wall motion and determining the residual ischemia in the chronic stage based on the presence or absence of this discrepancy.     

Evaluation of myocardial damage using 123I-BMIPP imaging in patients with vasospastic angina

The purpose of this study is to determine whether left ventricular dysfunction following coronary artery spasm by 123I-BMIPP myocardial imaging. To reveal the clinical efficacy of 123I-BMIPP SPECT, 20 patients with vasospastic angina were studied using resting, 3-hour delayed image with 123I-BMIPP and exercise, 3-hour delayed image with 201Tl SPECT. 123I-BMIPP uptake was decreased compared to 201Tl (discordant) in 12 patients (60%) and in 49/100 myocardial segments (49%). The extent and severity score in resting image with 123I-BMIPP were significantly larger than that in delayed image with 201Tl (p < 0.01). In 123I-BMIPP SPECT, the severity score in the latest ischemia were significantly larger than that in others. The incidence of a complete agreement of decreased 123I-BMIPP uptake and coronary artery spasm was significantly higher (75%) than that in 201Tl (28%, p < 0.01). Furthermore, compared to 201Tl uptake, decreased 123I-BMIPP uptake much more corresponded to reduced wall motion in 9 of patients with mismatching. The severity of regional wall motion abnormality was significantly correlated with severity score of 123I-BMIPP. Late redistribution in delayed image with 123I-BMIPP was seen in 6 patients. The regional washout rate and the severity of regional wall motion abnormality in 6 patients was significantly lower than that in others (p < 0.05). Thus, metabolic abnormality assessed by 123I-BMIPP is well associated with left ventricular asynergy and spastic region in patients with vasospastic angina. In conclusion, 123I-BMIPP SPECT may sensitively delineate the impaired myocardium following coronary artery spasm, and it is very useful in diagnosing and estimating the severity of vasospastic angina.     

Intensive medical therapy versus coronary angioplasty for suppression of myocardial ischemia in survivors of acute myocardial infarction: a prospective, randomized pilot study

BACKGROUND: Patients who have inducible ischemia after acute myocardial infarction (AMI) generally undergo coronary angiography with the intent to revascularize. Whether this approach is superior to intensive treatment with anti-ischemic medications is unknown. METHODS AND RESULTS: We performed a prospective, randomized pilot study comparing intensive medical therapy with coronary angioplasty (PTCA) for suppression of myocardial ischemia in 44 stable survivors of AMI. Myocardial ischemia was quantified with adenosine 201Tl tomography (SPECT) performed 4.5+/-2.9 days after AMI. All patients at baseline had a large total (>/=20%) and ischemic (>/=10%) left ventricular perfusion defect size (PDS). SPECT was repeated at 43+/-26 days after therapy was optimized. The total stress-induced PDS was comparably reduced with medical therapy (from 38+/-13% to 26+/-16%; P<0.0001) and PTCA (from 35+/-12% to 20+/-16%; P<0.0001). The reduction in ischemic PDS was also similar (P=NS) in both groups. Cardiac events occurred in 7 of 44 patients over 12+/-5 months. Patients who remained clinically stable had a greater reduction in ischemic PDS (-13+/-9%) than those who had a recurrent cardiac event (-5+/-7%; P<0.02). Event-free survival was superior in the 24 patients who had a significant (>/=9%) reduction in PDS (96%) compared with those who did not (65%; P=0.009). CONCLUSIONS: In this small pilot study, intensive medical therapy and PTCA were comparable at suppressing ischemia in stable patients after AMI. Sequential imaging with adenosine SPECT can track changes in PDS after anti-ischemic therapies and thereby predict subsequent outcome. Corroboration of these preliminary findings in a larger cardiac-event trial is warranted.     

Clinical value of triple-energy window scatter correction in simultaneous dual-isotope single-photon emission tomography with 123I-BMIPP and 201Tl

To improve the image quality in simultaneous dual-isotope single-photon emission tomography (SPET) with iodine-123 labelled 15-(p-iodophenyl)-3-methylpentadecanoic acid (BMIPP) and thallium-201, we applied the triple-energy window method (TEW) for correction of the cross-talk and scatter artifact. Seventy-one patients with coronary artery disease were included. 201Tl cross-talk into the 123I acquisition window (group 1, n = 30) and 123I cross-talk into the 201Tl window (group 2, n = 41) were studied. In group 1, 123I images were first obtained (single-isotope images), followed by 201Tl injection and SPET acquisition using dual-isotope windows (dual-isotope images). In group 2, the order was reversed. The dual-isotope SPET images with and without TEW were compared with the single-isotope images. Qualitative evaluation was performed by scoring the segmental defect pattern. Detectability of the mismatched fatty acid metabolism on dual-isotope SPET was evaluated by receiver operating characteristic (ROC) curve analysis. Segmental defect pattern agreement between dual and corrected single images was significantly improved by TEW correction (P<0.01). The agreement was particularly improved in segments with absence of uptake. There was no significant difference between TEW-corrected dual-isotope SPET and corresponding single-isotope SPET with regard to either % defect count or background activity. Mismatched fatty acid metabolism depicted by dual-isotope SPET predicted abnormal wall motion more accurately with TEW than without TEW. With TEW, a practical method for scatter and cross-talk correction in clinical settings, simultaneous dual 123I-BMIPP/201Tl SPET is feasible for the assessment of myocardial perfusion/metabolism mismatch.     

Saikosaponin b2 induces differentiation without growth inhibition in cultured B16 melanoma cells

Some patients of ischemic heart disease have low uptake in 123I-labeled beta methyl-iodophenyl penta-decanoic acid (BMIPP) SPECT in spite of normal uptake in thallium-201 (Tl) SPECT. To investigate their clinical significance, we performed both T1 and BMIPP myocardial SPECT in 26 cases with stable angina (n = 16) and unstable angina (n = 10), and compared with clinical backgrounds electrocardiogram (ECG) and left ventriculography (LVG). In 11 patients of them, the uptake of BMIPP was moderately reduced. We divided 26 cases into two groups according to uptake of BMIPP (normal/reduced). The two groups had no differences in length of angina attack and duration of disease, but they had a significant difference in the abnormality of either ECG or LVG. Three to six months after PTCA, we examined LVG in 18 cases, 12 of 16 cases with the abnormality of LVG showed the improvement of wall motion. We concluded the reduced uptake of BMIPP with normal uptake of Tl was related to more severe ischemia in cases with unstable angina.     

Assessment of 123I-beta-methyl iodophenyl pentadecanoic acid (BMIPP) myocardial scintigraphy in patients of chronic right ventricular overload--fatty acid metabolism in right ventricular myocardium

An investigation on the right ventricular pressure level and the abnormalities in the fatty acid metabolism of myocardium was made using 123I-beta-methyl-iodophenyl pentadecanoic acid (BMIPP) myocardial SPECT in patients with chronic right ventricular overloading. Twenty patients who presented with right ventricular systolic pressure (RVSP) of 35 mmHg or more were used as the subjects. Dual myocardial SPECT with 201TlCl (Tl) and BMIPP was carried out for the subjects and RVc/LVc, a ratio of radioactivity count incorporated in the right ventricular free wall to the left one was determined for Tl and BMIPP. And the correlations between RVc/LVc and RVSP, and RVc/LVc and RVSP/LVSP were examined. The subjects were classified into 3 groups based on the RVSP levels and the count ratio, BMIPP/Tl was compared among the three groups. With respect of Tl uptake, there were significant, positive correlations between RVc/LVc and RVSP (correlation coefficient r = 0.51, p < 0.05) and between RVc/LVc and RVSP/LVSP (correlation coefficient r = 0.59, p < 0.01). On the other hand, no significant correlation was found between them with respect of the uptake of BMIPP. The BMIPP/Tl ratio in the group with higher than 80 mmHg of RVSP was 0.82 +/- 0.06, which was significantly lower than the ratio's for two groups of less than 80 mmHg; 0.91 +/- 0.07 and 0.98 +/- 0.04 in the group with 35-49 and 50-79 mmHg of RVSP, respectively. These results show that when compared with BMIPP, Tl is superior for the estimation of right ventricular pressure. For the patients with right ventricular overloading, it was suggested that when RVSP reaches 80 mmHg or more, there appear some disorders in the fatty acid metabolism in the right ventricular myocardium.     

Impairment of regional fatty acid uptake in relation to wall motion and thallium-201 uptake in ischaemic but viable myocardium: assessment with iodine-123-labelled beta-methyl-branched fatty acid

In coronary artery disease, discrepancy in the uptake of thallium-201 and of methyl-branched fatty acid at rest has been described. The purpose of this study was to evaluate iodine-123 labelled beta-methyl-branched fatty acid (BMIPP) myocardial uptake and wall motion at rest in segments with stress-induced ischaemia identified by stress 201Tl tomography in patients with chronic coronary artery disease. 123I-BMIPP myocardial tomography was performed at rest and was compared with the findings of exercise-reinjection 201Tl tomography in 45 patients with chronic coronary artery disease. Regional wall motion was evaluated by contrast left ventriculography in 36 patients. Among 237 segments with reversible 201Tl defects, equally decreased uptake on both reinjection 201Tl and BMIPP images was observed in 93 (39%), more severely decreased uptake of BMIPP in 118 (50%) and more severely decreased uptake of reinjection 201Tl in 26 (11%). On the other hand, among 90 segments with non-reversible 201Tl defects, each pattern was observed in 71 (79%), 6 (7%) and 13 (14%) segments, respectively. When comparing the ischaemic segments with and without more severely reduced uptake of BMIPP than of reinjection 201Tl, wall motion was impaired to a greater extent in the segments with more severely reduced uptake of BMIPP than of reinjection 201Tl [severe hypo- or dyskinesis was present in 64 (70%) of 91 segments and in 24 (22%) of 110 segments, respectively, P<0.005]. In patients with chronic coronary artery disease, resting fatty acid uptake was frequently more reduced than reinjection 201Tl in the segments with stress-induced ischaemia, while in most of the fixed perfusion defects BMIPP and reinjection 201Tl uptake decreased concordantly. In ischaemic myocardium, wall motion was impaired to a greater extent in those segments which showed more severely reduced uptake of BMIPP than of reinjection 201Tl. In ischaemic but viable myocardium, discordant BMIPP uptake less than reinjection 201Tl uptake may indicate metabolic alterations and wall motion abnormality at rest independent of perfusion abnormalities. In conclusion, the combination of resting BMIPP and stress-reinjection 201Tl imaging may provide information on metabolic alterations and wall motion abnormality at rest independent of perfusion abnormalities.     

Evaluation of myocardial perfusion and fatty acid uptake using a single injection of iodine-123-BMIPP in patients with acute coronary syndromes

The purpose of this study was to clarify the possibility of simultaneous evaluation of myocardial perfusion and fatty acid metabolism using a single injection of 123I-beta-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) in patients with acute coronary syndromes. METHODS: Thirty patients with unstable angina pectoris (UAP group) and 15 patients with acute myocardial infarction (MI group) were studied. BMIPP dynamic SPECT was performed 2 min after the injection of BMIPP (185 MBq), and images were obtained every 3 min for 15 min with a three-head gamma camera. Conventional BMIPP SPECT was also performed 30 min after the injection. Serial BMIPP and resting 201TI images were compared. RESULTS: A 201TI-BMIPP mismatch between 30-min BMIPP and resting 201TI images was observed in 27 of 30 patients in the UAP group and 8 of 15 patients in the MI group, respectively. However, a 201TI-BMIPP mismatch between early (2-5-min) BMIPP and resting 201TI images was observed in only 2 of 30 patients in the UAP group and in only 2 of 15 patients in the MI group, respectively. The kappa statistics of tracer uptake between early BMIPP and resting 201TI images showed good concordance in UAP (kappa = 0.823) and MI (kappa = 0.765) groups, respectively. These results indicated that initial distribution of BMIPP reflects myocardial perfusion in patients with acute coronary syndromes. CONCLUSION: Myocardial perfusion and fatty acid metabolism can be evaluated simultaneously using a single injection of BMIPP, when images are taken soon (2-5 min) and long after the injection in patients with acute coronary syndromes.     

Scintigraphic assessment of silent myocardial ischaemia after early infarction using myocardial SPET imaging with 201Tl and 123I-MIBG

To test the hypothesis that myocardial sympathetic denervation reflects silent myocardial ischaemia early after infarction, 12 patients with myocardial infarction but without post-infarction angina pectoris underwent single photon emission tomography (SPET) at rest with 201Tl and 123I-metaiodobenzylguanidine (MIBG) shortly after and 3 months after infarction. Short-axis SPET images at the basal, mid-ventricular and apical portions of the left ventricle were selected, and each short-axis image was divided into eight segments. Tracer uptake in each of the 24 segments was scored using a 4-point scale. The total score in each segment was calculated as the defect score for each image, and the difference between the total defect score for the 201Tl and 123I-MIBG images was calculated as the delta defect score. All 12 patients underwent exercise stress 201Tl scintigraphy 1 month after infarction, and they were divided into two groups: those patients with (Group A, n = 7) and those patients without (Group B, n = 5) transient perfusion defects in the peri-infarcted region without chest pain. For the 123I-MIBG defect score, a marked reduction at 3 months was observed in Group A (24 +/- 12 vs 13 +/- 6; P < 0.01), whereas the defect score remained unchanged in Group B (25 +/- 7 vs 23 +/- 8; N.S.). The delta defect score was significantly reduced in Group A (10 +/- 5 vs 6 +/- 4; P < 0.05), whereas it remained unchanged in Group B. The 123I-MIBG defect score early after infarction was higher than the exercise-induced 201Tl defect score (24 +/- 12 vs 20 +/- 9; P < 0.01), whereas at 3 months post-infarction it was lower than the exercise-induced 201Tl defect score (13 +/- 6 vs 20 +/- 9; P < 0.05). Moreover, effort chest pain during daily activities was noted in 5 of the 7 (71%) patients in Group A within 3 months post-infarction. The results of this study suggest that viable but denervated myocardium (mismatched 123I-MIBG defects) is present in peri-infarcted regions, and that myocardial sensory nervous disturbance, which may co-exist with sympathetic nervous denervation, may induce silent myocardial ischaemia in patients with myocardial infarction.     

Extraskeletal primary osteosarcoma of the frontal region]

This article presents two cases with preserved myocardial 201Tl uptake and absent uptake of two kinds of radioiodinated fatty acids: iodine-123-labeled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) and iodine-123-labeled 15-(p-iodophenyl)-9-(R,S)-methylpentadecanoic acid (9MPA). Although coronary angiography showed no stenotic lesion and left ventriculography revealed no wall motion abnormality, no myocardial uptake of BMIPP and 9MPA was observed in the first case. In the second case, no myocardial accumulation was recognized even in the initial phase of dynamic SPECT acquired soon after the injection of 9MPA. The results suggest that the non-visualized myocardium was not specific for BMIPP imaging and that rather than the early back diffusion of the tracers from the myocardium, abnormality of the myocardial cell membrane was a possible mechanism accounting for the phenomenon.     

Molecular biology of iron and zinc uptake in eukaryotes

This study was designed to evaluate the feasibility of assessing myocardial viability using glucose loading followed by 201Tl SPECT. METHODS: First, the effect of insulin on the kinetics of 201Tl uptake was evaluated in isolated perfused rat hearts. Second, glucose-loading 201Tl myocardial SPECT was performed in 13 nondiabetic patients with histories of anterior myocardial infarction. Thirty minutes before acquiring rest 201Tl SPECT, 20 g of glucose were intravenously injected into the fasting subjects. Thallium perfusion defects were compared to those of conventional rest-redistribution SPECT images obtained within a 2-wk interval. SPECT images were divided into 21 segments, and a defect score in 17 segments was calculated as a sum of the semiquantitative defect scores (0 = normal; 1 = mildly decreased uptake; 2 = severely decreased uptake; 3 = absence of uptake). RESULTS: Thallium-201 uptake in isolated hearts showed a significant increase of 26% after insulin loading. Eleven (24%) of 45 segments showing perfusion defects on the conventional rest SPECT images demonstrated 201Tl uptake on glucose-loading SPECT imaging. Defect scores decreased significantly on the glucose-loading SPECT images (9.9 +/- 2.2 in early images; mean +/- s.e.) compared with the conventional rest-redistribution SPECT images (12.6 +/- 6.9 in delayed images, p < 0.05). CONCLUSION: Glucose-loading SPECT represents a superior method for assessing myocardial viability using 201Tl.     

Hypertrophic cardiomyopathy showing no 123I-BMIPP myocardial accumulation with type I CD36 deficiency

A 57 years old male consulted our hospital in complaining chest oppression and short of breath. Familial and dilated phase hypertrophic cardiomyopathy (HCM) was detected by ECG, echocardiography, left ventriculography and left ventricular endomyocardial biopsy. 201T1 SPECT showed regional increased accumulation in the ventricular septum, however, no myocardial accumulation of 123I-beta-methyl-p-iodophenylpentadecanoic acid (123I-BMIPP) was observed. We analyzed CD36 in this patient, and found he had type 1 CD36 deficiency. Myocardial uptake of long-chain fatty acids occurs via a specific transporter, which is homologous with human CD36. We hypothesize that CD36 deficiency, especially type 1 CD36 deficiency, might be one factor of no myocardial 123I-BMIPP uptake.     

Evaluation of myocardial uptake of beta-methyl-(123I)-iodophenylpentadecanoic acid (123I-BMIPP)

To evaluate the myocardial uptake of beta-methyl-(123I)-iodophenylpentadecanoic acid (123I-BMIPP), nineteen patients with ischemic heart disease including left ventricular hypertrophy (mean age 63 +/- 7.8, 14 males and 5 females) underwent BMIPP myocardial scintigraphy. Myocardial uptake (MU) of BMIPP to the total injected dose was calculated from anterior view of the planar image in all subjects, and was compared with plasma glucose (BS), triglyceride (TG), and free fatty acid (FFA). It was also compared with left ventricular mass (LVM) calculated with echocardiography. MU was not related to BS, TG, and FFA, however had the positive correlation with LVM (r = 0.676, p < 0.01). Myocardial uptake per left ventricular mass (MU/LVM) had the negative correlation with LVM (r = -0.671, p < 0.01). Further studies for the significance of MU/LVM will be required.     

Use of exercise technetium-99m sestamibi SPECT imaging to detect residual ischemia and for risk stratification after acute myocardial infarction

The clinical presentation, electrocardiographic findings, and technetium-99m sestamibi single-photon emission computed tomography (SPECT) imaging results of 134 consecutive patients who underwent nuclear exercise testing within 14 days of an acute myocardial infarction (AMI) were correlated with cardiac events over a 15 +/- 10-month follow-up. Whereas only 23 patients (17%) had chest pain and 31 (23%) had ischemic ST-segment depression during exercise, 94 (70%) had ischemia on SPECT (p < 0.001). On follow-up, 13 patients experienced a cardiac event: 7 were rehospitalized for unstable angina, 3 had recurrent AMI, and 3 died of cardiac causes. Ischemia on the sestamibi images identified 11 of these patients (85%), whereas chest pain identified only 3 (23%, p = 0.006), and electrocardiographic ischemia identified only 4 (31%, p = 0.017). The presence of either ischemia as seen on SPECT or defects in multiple vascular territories identified 12 patients (92%) with an event, including all who had cardiac death. By Cox regression analysis of clinical, stress, and image parameters, the number of ischemic defects on SPECT was the only significant correlate of a future event (chi-square = 4.62, p = 0.03), and patients with > or = 3 reversible sestamibi defects had an event rate of 38%. The extent of ischemia as seen on nuclear imaging remained a strong correlate (p = 0.008) of an event in the 54 patients (40%) who had received thrombolytic therapy. Thus, exercise technetium-99m sestamibi SPECT after AMI frequently reveals residual ischemia, and is better than clinical data, symptoms, and stress electrocardiographic data in identifying patients who will have a subsequent cardiac event.     

Genetic and developmental influences on infant mouse ultrasonic calling. II. Developmental patterns in the calls of mice 2-12 days of age

Both 360 degrees and 180 degrees rotation acquisition methods have been used in myocardial single photon emission tomography (SPET) studies. We compared both methods using 201Tl, 99Tcm and 123I radiopharmaceuticals with phantoms and clinical models. Myocardial phantom studies with anterior and inferior defects were performed using 201Tl, 99Tcm and 123I. Clinical models of 14 typical situations, including normal subjects, patients with anterior or inferior defects and a high right hemi-diaphragm, were studied. The radiopharmaceuticals were 201Tl, 99Tcm-sestamibi, 123I-BMIPP and 123I-MIBG. Four sets of 180 degrees anterior rotation data with starting angles of (A) posterior, (B) LPO 30 degrees, (C) LPO 60 degrees and (D) left lateral direction were generated and compared with 360 degrees rotation SPET. A polar map display was used for quantification. In phantom studies, the defect contrast on the map was higher in the anterior defect with 180 degrees rotation than with 360 degrees rotation. However, it was decreased in the inferior defect, particularly with 201Tl, because of decreased wall activity around the defect. In the patient model with anterior or inferior defects, the defect contrast was improved with 180 degrees SPET by up to 10%. A slight decrease in the normal region was also noted in the 180 degrees reconstruction. The effect of diffuse liver activity on the inferior region depended on the rotation range. A patient with a high right hemi-diaphragm showed a lower inferior count with 360 degrees SPET. In conclusion, the 360 degrees acquisition was superior to the 180 degrees acquisition in the phantom with defects. Clinically, the quantitative differences in radionuclide types (99Tcm, 123I or 201Tl) were not significant for quantifying a moderate degree (50-60% of peak count) of defect. However, we note quantitative variation depending on the rotation range in the 180 degrees method.     

Propanil affects transcriptional and posttranscriptional regulation of IL-2 expression in activated EL-4 cells

OBJECTIVE: To determine the clinical and prognostic value of identifying metabolic abnormalities of myocardial fatty acid metabolism in idiopathic dilated cardiomyopathy using iodine-123 beta-methyl-iodophenyl pentadecanoic acid (123I BMIPP). SETTING: Cardiac care division in national hospital. PATIENTS: 32 consecutive patients with idiopathic dilated cardiomyopathy in whom both 123I BMIPP and thallium-201 myocardial single photon emission computed tomography were performed. METHODS: The uptake of each tracer was scored visually from 0 (normal) to 3 (defect) in 17 segments (eight basal, eight midventricular, and one apical). A total score for all 17 segments was compared with clinicopathological variables. Prognostic value of mismatches between the two tracers were also evaluated. RESULTS: The 123I BMIPP total score was correlated with pulmonary capillary wedge pressure (r = 0.68, p < 0.001), left ventricular end diastolic pressure (r = 0.65, p < 0.001), percentage fractional shortening at six months' follow up (r = -0.58, p = 0. 001), myocyte diameter (r = 0.66, p < 0.001), and percentage area of interstitial fibrosis (r = 0.69, p < 0.001) measured by morphometry in the biopsy specimens. During a mean (SD) follow up of 20 (11) months, deterioration of the New York Heart Association functional class was observed in 11 of the 32 patients; four of these died. Segments with a greater decrease in 123I BMIPP than thallium-201 uptake (type B mismatching) were often observed in patients with deterioration (88/187, 29% v 58/357, 16%; p < 0.001). CONCLUSIONS: The extent of the abnormality of myocardial fatty acid metabolism in idiopathic dilated cardiomyopathy reflects the severity of haemodynamic deterioration and histopathological changes. Type B mismatching is one of the important prognostic indicators in idiopathic dilated cardiomyopathy.     

Oxygen consumption, lactate metabolism, and gastric intramucosal pH in an experimental liver transplantation model

We have evaluated whether myocardial uptake of the fatty acid analog 123I-15-(p-iodophenyl)-3-R,S-methyl pentadecanoic acid (BMIPP) is dependent on the dietary state. METHODS: We compared the biodistribution of 150 MBq of 123I-BMIPP in six healthy volunteers in two states: after at least 12 hr of fasting and after oral glucose loading (75 g) 60 min before tracer administration, followed by a meal enriched in carbohydrates and protein. Planar and tomographic acquisitions were performed over a 4-hr time period after tracer injection; data were corrected for radioactive decay and injected dose. Radioactivity was measured in blood samples drawn at several points. RESULTS: Significant increases of glycemia and insulinemia and a significant drop in plasma nonesterified acids were documented after glucose loading. Half-time values for plasma radioactivity were significantly shorter in the glucose-loaded state than in the fasted state (4.3 +/- 1.4 min compared to 6.3 +/- 1.3 min, p < 0.05). Activity in the heart and liver tended to be higher in the glucose-loaded state than in the fasted state. SPECT images at 0.5 hr after tracer injection demonstrated that the myocardial wall-to-cavity ratio was higher after glucose than in the fasted state (2.53 +/- 0.59 compared to 2.11 +/- 0.21, p = 0.15). Washout from the liver between 1 and 4 hr after injection increased from 18.6% +/- 4.4% in the fasted study to 24.1% +/- 2.4% after glucose (p = 0.04). Washout from the myocardium between 0.5 and 3.5 hr after injection increased from 13.1% +/- 8.8% in the fasted study to 24.0% +/- 3.7% after glucose (p = 0.05). CONCLUSION: These results indicate that fasting before BMIPP scintigraphy is not mandatory to obtain adequate SPECT images. At the tire when SPECT is usually performed, glucose loading may provide improved ratios between myocardial and blood pool activity.     

ECG-gated dual-isotope myocardial SPECT with 201Tl and 99mTc-tetrofosmin: simultaneous assessment of stress/rest myocardial perfusion and left ventricular function

ECG-gated dual-isotope acquisition protocol involving rest imaging with 201Tl and stress 99mTc-tetrofosmin (TF) SPECT was designed for the simultaneous assessment of rest/stress myocardial perfusion and rest ventricular systolic function. This study assessed the feasibility and diagnostic accuracy of this protocol. Forty-five patients underwent the dual-isotope SPECT protocol. Twenty minutes after resting injection of 111 MBq of 201Tl, 370 MBq of 99mTc-TF was administered at a peak exercise. The dual-isotope gated SPECT acquisition was performed 1 hour later. Then, the regional count increase rate (%WT) of 99mTc-TF from end-diastole end-systole was calculated using an automated method which was developed for quantification of regional wall thickening based on circumferential profile analysis in our laboratory. Myocardial perfusion and contractility analysis was carried out using 8 segments of left ventricle with comparison of coronary angiographical findings. The sensitivity and specificity for the detection of diseased coronary vessels (> = or 75% stenosis) were 76% and 94%, respectively. Infarcted regions showing reversible defect had significantly greater %WT as compared with those with fixed defects (63 seg; 12.7 +/- 6.1% vs. 36 seg; 8.9 +/- 7.2%, p < 0.01). In conclusion, this dual-isotope protocol has some advantages; i.e., shortening an examination time, having the exact registration of stress/rest perfusion, and simultaneous evaluation of resting regional wall thickening.     

Stress and rest myocardial SPET quantification with 201Tl and 99Tcm-tetrofosmin: a comparison

99Tcm-tetrofosmin is a new myocardial perfusion agent that has excellent physical and pharmacokinetic characteristics for performing tomographic myocardial perfusion studies. The aim of this study was to compare the behaviour of 99Tcm-tetrofosmin and 201Tl in the assessment of ischaemia and viability in patients with previous myocardial infarction. Twenty consecutive patients who had suffered infarction and been referred for assessment of ischaemia and myocardial viability were enrolled into the study. Each patient underwent two stress tests performed no more than 10 days apart, one with a 201Tl exercise-reinjection-redistribution method and one with a 99Tcm-tetrofosmin short protocol (exercise-rest). The results were quantified using polar maps to represent images for stress, rest and reversibility. The post-stress images showed there was a slight tendency to overestimate defect size with 99Tcm-tetrofosmin in the lateral region (P < 0.006). We found no significant differences between the two tracers when comparing reversibility. The same defect size at rest were obtained when the maps for 201Tl with uptake of 50% were compared with those for 99Tcm-tetrofosmin with uptake of 45%. Agreement between the two agents for assessment of viability was 93%. We conclude that the quantitative assessment of myocardial ischaemia and uptake of 99Tcm-tetrofosmin at rest are comparable to those obtained with 201Tl in patients who have suffered myocardial infarction.     

Prognosis of "clandestine" myocardial ischemia, silent myocardial ischemia, and angina pectoris in medically treated patients

The aim of this study was to assess the prognosis of medically treated patients with "clandestine" myocardial ischemia (perfusion defect without angina and no ST depression > 1 mm during exercise test) compared to those with silent myocardial ischemia (ST-segment depression > 1 mm, without angina) and those with angina pectoris. One hundred twelve patients without previous myocardial infarction were included. All patients underwent a symptom-limited exercise test on a bicycle ergometer, myocardial perfusion technetium-99m-methoxy-isobutyl-isonitrile single-photon emission computed tomography (SPECT), and coronary angiography. They were classified into 3 groups (angina group, 34 patients; silent group, 20 patients; and the clandestine group, 58 patients). The mean follow-up was 3.6 years (range 6 months to 5.5 years). Patients with clandestine ischemia had a lower scintigraphic and angiographic score than patients with silent ischemia (25+/-8 vs 31+/-9 and 24+/-8 vs 29+/-7, p = 0.008, respectively), but the prognosis was similar. Only angina and severe reversible SPECT defects were predictive for cardiac events: death + myocardial infarction + revascularization. We conclude that in medically treated patients without previous myocardial infarction, angina and severe reversible SPECT defects are predictive for cardiac events only when the need for revascularization is included as a cardiac event.