Comparison of inferior myocardial defect between planar and SPECT image of 123I-metaiodobenzylguanidine cardiac scintigraphy

Discordant findings of inferior MIBG defect between SPECT and planar images were sometimes observed in the clinical studies. In this study, we compared inferior myocardial findings between planar and SPECT image of 123I-metaiodobenzyl-guanidine (MIBG) cardiac scintigraphy in 29 patients. All patients were estimated as normal in anterior accumulation of MIBG. The patients were divided into 3 groups according to the visual finding of inferior defect in the planar and SPECT image; normal group (normal inferior accumulation of MIBG both in the planar and SPECT image, N = 10), discordance group (inferior MIBG defect was only observed in the SPECT image, but was not observed in the planar image, N = 7), inferior defect group (inferior MIBG defect was observed both in the planar and SPECT image, N = 12). Inferior/anterior count ratio of SPECT and planar image were 0.96 +/- 0.11 vs. 0.97 +/- 0.05 in normal group, 0.59 +/- 0.21 vs. 0.99 +/- 0.13 in discordance group, 0.46 +/- 0.13 vs. 0.82 +/- 0.04 in inferior defect group. Liver/heart count ratio was significantly higher in the discordance group (2.07 +/- 0.49) than that in the normal (1.14 +/- 0.15) and inferior defect group (1.45 +/- 0.39). In phantom study, it has been reported that increased liver accumulation of MIBG causes artifactual inferior defect adjacent to the liver. These data indicate that increased liver/heart count ratio may cause artifactual inferior defect on MIBG SPECT image in the clinical studies. Planar image evaluation may be helpful to distinct the artifactual inferior defect on SPECT image.     

123I-metaiodobenzylguanidine (MIBG) scintigraphy for the staging of neuroblastoma

Nineteen children with neuroblastoma (aged 2 w.-7 y.o.) were studied to evaluate the optimal scan conditions for Iodine-123-Metaiodobenzylguanidine (MIBG) scintigraphy for accurate staging at the time of diagnosis. Six and 24 hours after an injection of 123I-MIBG, whole body image and truncal spot and SPECT images were obtained. Compared with other studies (CT or MRI and bone scintigraphy), each 123I-MIBG image was evaluated visually to investigate which image can demonstrate the extent of neuroblastoma most exactly. MIBG images demonstrated primary tumors in all patients, and metastatic lymphadenopathy in 8 of 9 patients. Twenty-four hour SPECT images gave us the most detailed information about the extent of abnormal accumulation. As to bone and bone marrow lesions, 6 hour images were superior to 24 hour images in detectability. Moreover, MIBG showed many more lesions and more extended accumulation than the bone scan. 123I-MIBG scintigraphy was very useful in detecting neuroblastomas. In order to get the most valuable information, both delayed SPECT and early whole body planar images should be obtained.     

Influence of ergometric parameters on the results of myocardial perfusion tomographic scintigraphy

BACKGROUND: The percentage of peak predicted heart rate that is accepted to consider as sufficient a given exercise test is 85%. However, the optimal value of such rate and other exercise parameters for the purposes of myocardial single-photon emission tomography is not well established. PATIENTS AND METHODS: With the aim of establishing the minimal levels of maximal heart rate, product heart rate x systolic blood pressure and ventilatory oxygen uptake to obtain an adequate diagnostic efficacy of myocardial perfusion scintigraphy, 159 patients with coronary artery disease or suspicion of this without previous myocardial infarction were studied with stress test single photon emission tomography with 99mTc-methoxi-isobutil-isonitrile. All the patients were coronary angiography tested. RESULTS: Sensitivity and negative predictive value were significantly higher at levels of heart rate > 80% (93 vs 78%; p = 0.002 and 94 vs 56%; p = 0.0004), product heart rate x systolic blood pressure > 18,000 (88 vs 78%; p = 0.04 and 84 vs 52%; p = 0.004) and > 5 METs (85 vs 77%; p = 0.002 and 74 vs 69%; p = 0.03). CONCLUSIONS: Sensitivity and negative predictive value of stress test single photon emission tomography with 99mTc-methoxi-isobutil-isonitrile are low if levels higher than 80% of heart rate, 18,000 of product of heart rate x systolic blood pressure and 5 METs have not been achieved.     

The role of myocardial apoptosis in the development of heart failure

Heart failure can result from a variety of causes, including volume or pressure overload and contractile disturbances of the myocardium. Loss of myocytes is an important mechanism in the development of cardiac failure. In general, myocyte death resulting in progressive deterioration of myocardial function is attributed to necrosis, but recently the involvement of programmed cell death (mainly apoptosis) has been suggested. The authors review the possible role of myocardial apoptosis in developing of heart failure. Subcellular genetic regulatory processes as well as the pharmacological susceptibility of programmed cell death are also discussed. In heart failure, significant amount of cardiac myocytes undergoes apoptosis, that unlike necrosis can be prevented. Specific inhibition of this process could mean a considerable part of cardioprotection after thorough understanding of the underlying cellular mechanisms.     

Reappraisal of quantitative esophageal scintigraphy by optimizing results with ROC analyses

This study investigates whether systematic analyses of methodological issues contribute to improve and renew the diagnostic role of quantitate esophageal scintigraphy. METHODS: Forty-seven patients with normal (n = 26) and pathologic (n = 21) esophageal function were studied with scintigraphy and manometry, using the latter findings as the gold standard. Scintigraphic data were analyzed by receiver operator characteristic (ROC) methods to: establish the optimal decision threshold for six different quantitative parameters, evaluate their inherent discrimination capacity and compare liquid compared with solid bolus data. RESULTS: Quantitative parameters have shown remarkable differences in their potential to discriminate between normal and pathologic findings (percentage of emptying at definite time points > mean time > transit time > mean transit time > Tmax). Sensitivity of 95% at a specificity of 96% was the optimum obtained. At comparable specificity levels, solid bolus studies generally demonstrated higher sensitivity than liquid bolus studies. CONCLUSION: The diagnostic performance of optimized esophageal scintigraphy is close to that of manometry. Our findings do not only renew the role of esophageal scintigraphy as an accurate screening test for esophageal motility disorders but also invalidate recent reservations about the diagnostic potential of this method.     

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.     

123I-MIBG myocardial scintigraphy in diabetic patients: relationship with 201Tl uptake and cardiac autonomic function

The purpose of this study is to investigate the effects of aging on the human stretch reflexes. The EMG and torque responses of the stretch reflex of the wrist flexors were evoked by ramp-and-hold mechanical perturbations. The stretch reflexes were recorded at seven test conditions with different stretch velocity and muscle preload. The test results from young and older healthy adult subjects were compared. In average, the absolute amplitude of the short-latency (20-40 ms) EMG (recorded from flexor carpi radialis) reflex response was significantly lower in the older group. If the data were normalized and expressed in percentage of the maximal voluntary EMG activity, however, this group difference was not significant. There was no change in the reflex gain of the short-latency reflex with aging. For the long-latency (50-90 ms) EMG reflex response, both the normalized amplitude and the reflex gain were significantly enhanced with aging, probably through supraspinal mechanisms. There was no significant difference in the threshold velocity for the evoked EMG reflexive activities between age groups. There were also no changes in the reflexive wrist flexion torque with aging. These results suggested that the number of motor units recruited during the stretch reflex activity declined with aging although the percentage of motor units recruited was not affected by aging. It is concluded that the central regulating mechanisms of the spinal motoneuron excitability are not compromised by aging. The automatic gain compensation phenomenon is also preserved with aging.     

Management of heart failure complicating acute myocardial infarction

Development of heart failure complicating acute myocardial infarction is directly related to the extent of myocardial infarction and complex architectural changes defined as infarct expansion and remodeling. ACE inhibitors are an exciting class of agents that have the potentiality to prevent left ventricular dilatation, evolution of heart failure and death in the acute myocardial infarction setting. Besides, reperfusion is a important intervention that prevents infarct expansion in the early period after myocardial infarction. Early reperfusion limits expansion by infarct size reduction while late reperfusion reduces expansion independent of myocardial salvage by limiting transmural damage and improving the infarct healing. Therefore, reperfusion therapy decreases the incidence of congestive heart failure and significantly improves the prognosis of heart failure. On the other hand, the in-hospital mortality rate of cardiogenic shock, resulting from acute myocardial infarction, remains high, although primary PTCA has apparently resulted in substantial improvement in mortality of myocardial infarction shock. Thus, reperfusion treatment may be more effective in preventing rather than treating cardiogenic shock.     

Extracorporeal membrane oxygenation in myocardial failure after pediatric heart surgery

In spite of progressive improvement not only in myocardial protection but also in anesthetic and surgical techniques, the repair of complex congenital heart defects can still lead to cardiopulmonary compromise refractory to conventional treatment. We describe two patients in whom successful surgical repair of congenital heart defects was followed by severe heart failure refractory to medical treatment. Both patients were managed by extracorporeal membrane oxygenation (ECMO). We discuss the indications, contraindications and use of ECMO in the postoperative intensive care unit.     

111In-pentetreotide scintigraphy is superior to 123I-MIBG scintigraphy in the diagnosis and location of chemodectoma

Chemodectomas, or glomus tumours, are unusual head and neck paragangliomas. A non-invasive imaging technique, 123I-metaiodobenzylguanidine (123I-MIBG) scintigraphy, has long been used for the diagnosis of all types of paraganglioma. The aim of this study was to evaluate and compare classic 123I-MIBG scintigraphy with the more recent 111In-pentetreotide scintigraphy in the diagnosis and location of chemodectomas. We performed 123I-MIBG and 111In-pentetreotide scintigraphy in eight patients (7 females, 1 male) with histologically or radiologically confirmed chemodectomas (five carotid body and three jugulotympanic chemodectomas). 123I-MIBG uptake was visualized in four patients on planar views and SPET images (sensitivity 50%); uptake was low in three patients. Using 111In-pentetreotide scintigraphy, all chemodectomas in eight patients were visualized (sensitivity 100%) and 111In-pentetreotide uptake was high in all cases. In conclusion, our results indicate that 111In-pentetreotide scintigraphy is superior to 123I-MIBG scintigraphy in the diagnosis and location of chemodectomas. In-pentetreotide or 123I-MIBG uptake suggests a neuroendocrine origin, providing important functional information in the diagnosis of chemodectomas. Moreover, 111In-pentetreotide scintigraphy permits a good classification of patients with or without somatostatin receptors in the chemodectoma in the application of pharmacological therapy with somatostatin analogues to inoperable tumours. The main therapeutic action of cold somatostatin analogues is to inhibit hormonal hypersecretion in different neuroendocrine tumours. In chemodectomas, however, the most important effect of somatostatin analogues is to reduce tumour volume or inhibit growth progression.     

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.     

Changes in fatty acid compositions of myocardial lipids in rats with heart failure following myocardial infarction

Changes in fatty acid composition of myocardial lipids were examined in rats with heart failure following myocardial infarction. Left ventricular systolic pressure (LVSP) was decreased and left ventricular end-diastolic pressure (LVEDP) was elevated 24 h, 1 and 12 weeks after left coronary artery ligation (CAL), suggesting the development of heart failure at these periods in this model. Hearts were isolated 24 h, 1 week and 12 weeks after the operation. Myocardial lipids in the infarcted scar tissue, non-infarcted remaining left ventricle including interseptum and right ventricle were separated into phospholipid (PL), triacylglycerol (TG), diacylglycerol (DAG) and free fatty acid (FFA) fractions. In the scar tissue PL content markedly decreased whereas TG, DAG and FFA contents increased 24 h after CAL. Despite a marked decrease in constituted fatty acids of PL fraction in the scar tissue the percentage of arachidonic acid in PL was elevated 12 weeks after CAL, suggesting that release of arachidonic acid during PL degradation was suppressed. In the non-infarcted viable left ventricle PL content remained unchanged throughout the experiment whereas TG, DAG and FFA contents were elevated 24 h after CAL. Despite no changes in PL and other lipid contents in the non-infarcted tissue the percentage of linoleic acid in PL was reduced and that of docosahexaenoic acid in PL was elevated 12 weeks after CAL. Our findings showed that myocardial lipid composition of the non-infarcted left ventricle was altered only in an early stage of the development of heart failure and fatty acid compositions of PL was exchanged in a late stage of the development of heart failure. The exchange may be related to cardiac dysfunction or myocardial remodelling in the rat with heart failure.     

I-123 MIBG scintigraphy in adults. A report of clinical experience

Thirty-one adult patients with clinical findings suggestive of pheochromocytoma were studied with I-123 MIBG. All patients had images obtained at 24 and 48 hours. Five patients had abnormal uptake proved to be because of I-123 MIBG avid tumors. The remaining 26 patients had no proven tumors and showed physiologic uptake in various organs. The 24-hour images were of high quality. In all cases, the 48-hour images contributed no significant additional information. Only in 1 patient did the 48-hour image add some certainty. Physiologic uptake was seen in the salivary glands, liver, G.I. tract, and urinary bladder in all patients (100%). Uptake was also observed in the lung and heart (90%), normal adrenal glands (32%), thyroid (29%), spleen (23%) uterus (13%), and neck muscles (6%). The authors' experience indicates that I-123 MIBG gives superior images compared to the previously used I-131 MIBG, that the optimum imaging time for adults is 18-24 hours, and that normal distribution patterns including uterine and neck muscle uptake should be familiar to physicians interpreting the studies.     

A quantitative assessment of innervation in the conduction system of the calf heart

BACKGROUND: The aim of the present investigation was to determine the relative distribution of autonomic and sensory nerves in the cardiac conduction tissues of calves. METHODS: A quantitative immunohistochemical and histochemical technique was adopted. RESULTS: Immunoreactivity to the general neuronal marker protein gene product 9.5 (PGP 9.5) demonstrated that all regions of the conduction system possessed a higher relative density of total nerves when compared with the surrounding myocardial tissues. Unlike myocardial innervation, the conduction system did not display an atrial-to-ventricular gradient in nerve density. PGP 9.5-immunoreactive nerve trunks and varicose nerve fibres were more numerous in the transitional atrioventricular node and the penetrating atrioventricular bundle than in either the sinus node, compact atrioventricular node, or bundle branches. The Purkinje network of the ventricular conduction tissues possessed a rich supply of PGP 9.5-immunoreactive nerve trunks and varicose nerve fibres. Acetylcholinesterase (AChE)-positive nerves were the main subtype identified in the sinus and atrioventricular nodes and in the ventricular conduction tissues, representing 50-80% of the area occupied by PGP 9.5-immunoreactive nerves. The compact atrioventricular node possessed AChE-positive and tyrosine hydroxylase (TH)-immunoreactive nerves in similar proportions (45%), although, in general, TH-immunoreactive nerves had a lower relative nerve density than AChE-positive nerves. Neuropeptide Y (NPY)-immunoreactive nerves represented the main peptide-containing subpopulation and occurred throughout the conduction system, displaying a similar pattern of distribution and relative density to those demonstrating TH immunoreactivity. Nerve fibres immunoreactive for somatostatin, vasoactive intestinal polypeptide, substance P, and calcitonin gene-related peptide formed relatively minor subpopulations. CONCLUSIONS: The general innervation of the bovine conduction tissues exhibits significant regional variation. Throughout all regions of the conduction system, AChE-positive nerve represented the dominant subtype when compared with TH- and NPY-immunoreactive nerves. The distribution and relative density of nerve subtypes in the tissues of the bovine conduction system are similar to those observed in man, whereas differences were observed in other regions, such as the atrioventricular bundle and bundle branches. This finding must be considered by those making interspecies comparisons.     

Digoxin in heart failure: results of the recent Digoxin Investigation Group trial in the context of other treatments for heart failure

BACKGROUND: This case report is the first documentation of the occurrence and potential source of lethal graft-versus-host disease (GVHD) after simultaneous kidney-pancreas transplantation. The patient was a 27-year-old African-American male who received an ABO-compatible, five HLA antigen-mismatched kidney-pancreas transplant from a 17-year-old African-American female donor, who died after childbirth. METHODS: Preoperative crossmatches using lymphocytotoxicity and flow cytometry were negative. The patient received four blood transfusions within 10 days of transplantation. Immunosuppression consisted of OKT3 induction, and then cyclosporine, azathioprine, and corticosteroids. RESULTS: On postoperative day (POD) 9, the patient became febrile, and leukocytopenia and pancytopenia developed. Immunosuppression was reduced and granulocyte colony-stimulating factor was begun. Cultures were negative, interleukin 6 and interleukin 8 levels were elevated, and a cutaneous rash appeared on POD 18. A skin biopsy demonstrated dermatitis with focal epidermal necrosis consistent with GVHD. In an attempt to identify the source of GVHD, variable-number tandem repeat analysis fingerprinting was performed with DNA from donor splenocytes, from the skin biopsy, as well as from the patient's buccal mucosa. The skin biopsy showed a mixed variable-number tandem repeat analysis type containing DNA fragments matching the recipient and donor. Blood donors were excluded as a source because they were serologically different from the organ donor. The patient developed liver abnormalities and died from multiorgan failure on POD 22. CONCLUSIONS: We speculate that carryover of passenger donor lymphocytes within the transplanted organ were responsible for GVHD. Furthermore, donor traits such as sexual mismatching, African-American race, and alloimmune status may be important potential risk factors for GVHD.     

Influence of age and gender on quantitative sacroiliac joint scintigraphy

The value of quantitative sacroiliac joint scintigraphy for detecting sacroiliitis is controversial. Age and gender may contribute to this discordance. In previous reports, the number of control groups has been small and might not exactly reflect the change of sacroiliac/sacral (SI/S) ratios related to different age. In addition, the selection of control subjects was not strict. In most studies, care was not taken to ensure that control subjects did not have a history of back pain or any other relevant conditions. In addition, there was no requirement for a normal radiograph as a condition of inclusion. The aim of our study was to evaluate the consequent changes in SI/S ratios, according to age (in 10-yr intervals) and gender. METHODS: Over a period of 5 yr, 413 control subjects without a history of back pain, scoliosis, kyphosis, joint pain, arthritis, lesions within the pelvis, chemotherapy or systemic disease such as diabetes or systemic lupus erythematosus were included in this study. A posterior planar film of the pelvis was obtained to calculate SI/S ratio 3 hr after injection of 740 MBq 99mTc-methylenediphosphonate. Our data showed that: (a) the change in SI/S ratios related to age was significant in both females and males; (b) the SI/S ratios were higher in males younger than 30 yr and higher in men in the 41-50-yr age group and in females in other groups; (c) the SI/S ratios declined steadily with increasing age in females, whereas there were two plateaus in men aged 21-40 yr and 41-70 yr; (d) there were significant differences of SI/S ratios between the genders in certain age groups; and (e) no differences were found between left SI/S ratios and right SI/S ratios. CONCLUSION: The influence of age and gender on SI/S ratios are substantial, and it is essential for each department to establish its own values for SI/S ratios based on gender and age (in 10-yr intervals).