An evaluation of the British Army spatial disorientation sortie in U.S. Army aviation

A 68-year-old female whose myocardial sympathetic function was severely damaged with multi-vessel vasospastic angina is presented. She had no signs of autonomic dysfunction or diabetes mellitus. Myocardial imaging with 123I-MIBG showed extremely diminished uptake, but 201TlCl and 123I-BMIPP SPECT images were almost normal. Coronary arteriography revealed no significant atherosclerotic stenosis, multivessel spasm was observed by provocation test using acetylcholine. The extremely diminished uptake of 123I-MIBG was slightly increased in response to medication and the subsequent improvement of the patient's condition. Markedly decreased uptake with 123I-MIBG myocardial scintigraphy was considered to be due to multi-vessel spastic angina. We believe that this method of imaging study is useful for evaluating the healing stage of myocardial sympathetic dysfunction.     

Provocative testing for coronary arterial spasm: rationale, risk and clinical illustrations

Two cases of Prinzmetal's variant angina are presented in which coronary spasm was documented by electrocardiographic evidence obtained in the coronary care unit during provocative testing with ergonovine maleate after the arteriographic demonstration of anatomically normal coronary arteries. The rationale and risks of provocative testing for spasm in patients with chest pain and anatomically normal coronary arteries are reviewed. The advantages of performing provocative testing in the coronary care unit after arteriography rather than in the catheterization laboratory during coronary arteriography are discussed.     

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.     

Direct evidence of impaired cardiac sympathetic innervation in essential hypertensive patients with left ventricular hypertrophy

Increased sympathetic nervous activity has been proposed as one of the causes of left ventricular hypertrophy (LVH) associated with hypertension. However, the precise relationship is not fully understood. METHODS: To elucidate the relationship between myocardial sympathetic nervous activity and LVH in patients with essential hypertension EHT), we performed 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy in 49 patients with EHT and 17 normotensive control subjects. Sympathetic innervation of the left ventricle was evaluated using SPECT, and the whole heart uptake of the tracer was quantitatively assessed as the heart-to-mediastinum uptake ratio on both the early (15-min) and delayed (5-hr) images. Myocardial washout rate (MWR) of the tracer from 15 min to 5 hr after the isotope administration was also calculated. The left ventricular mass index (LVMI) was determined echocardiographically. RESULTS: In 49 hypertensive patients, there was a negative correlation between LVMI and heart-to-mediastinum uptake ratio on both the early and delayed images (r=-0.55, p < 0.0001; r=-0.63, p < 0.0001, respectively). In addition, there was a positive correlation between the LVMI and MWR of 123I-MIBG in these hypertensive patients (r=0.59, p < 0.0001). As for the regional uptake of the tracer, there was no significant difference between control subjects and hypertensive patients without cardiac hypertrophy, but a significant decrease of the uptake in the inferior and lateral regions was observed in hypertensive patients with cardiac hypertrophy. CONCLUSION: Patients with EHT had decreased accumulation and increased MWR of 123I-MIBG in proportion to the degree of LVH. Hypertensive patients with cardiac hypertrophy had impaired sympathetic innervation in the inferior and lateral regions of the left ventricle.     

Acute myocardial infarction during pregnancy caused by coronary artery spasm

A 33-year-old pregnant woman suffered from acute anteroseptal myocardial infarction at the 19th gestational week. Despite periodic attacks of myocardial ischaemia after admission, the coronary arteriograms under the use of nitroglycerin were normal. Thereafter, she remained free from the ischaemic events with diltiazem hydrochloride and delivered a healthy baby. The coronary arteriography at puerperium also showed no organic narrowing. However, the provocative test with acetylcholine chloride caused severe spasm of the left anterior descending coronary artery. These findings strongly suggest that acute myocardial infarction in this pregnant woman was caused by coronary artery spasm.     

Managed care and outcomes of hospitalization among elderly patients with congestive heart failure

123I-radiolabeled metaiodobenzylguanidine (123I-MIBG) cardiac imaging has been used to evaluate the distribution of sympathetic nervous system (SNS) in the heart. Different heart diseases have shown impaired cardiac SNS distribution as reflected by MIBG activity. The aim of this study was to assess the cardiac distribution of SNS in normal subjects, using MIBG imaging. Ten normal subjects (1 male and 9 females, mean age 46 +/- 9 years) with no cardiac abnormalities underwent myocardial 123I-MIBG scintigraphy, Tc-99m methoxyisobutylisonitrile (MIBI) cardiac perfusion imaging and equilibrium radionuclide angiography (RNA). Regional myocardial MIBG and MIBI activities were quantitatively evaluated using a region of interest analysis. For this purpose, the left ventricle was divided into 6 myocardial regions as anterior, apical, inferior, septum, lateral and posterolateral. In particular, myocardial MIBG and MIBI activities were measured as myocardium to mediastinum ratio. Regional left ventricular function was assessed by RNA. Myocardial MIBG uptake was homogeneous in anterior (2.2 +/- 0.5), inferior (2.5 +/- 0.7), septal (2.4 +/- 0.4), lateral (2.3 +/- 0.4), and posterolateral (2.3 +/- 0.4) regions. Conversely, MIBG uptake was significantly lower in the apical region (1.9 +/- 0.3) compared to all other left ventricular segments (p < 0.05). Regional myocardial perfusion, as measured by MIBI uptake, was homogeneous in all regions. No regional left ventricular wall motion abnormalities were observed by RNA. In conclusion, our data suggest that a decreased MIBG uptake may be observed in the left ventricular apical region of normal subjects reflecting reduced sympathetic innervation of the apex. This finding is not related to myocardial perfusion or wall motion abnormalities. The knowledge of cardiac sympathetic innervation in normal subjects may be helpful to assess SNS abnormalities in heart disease.     

Low prevalence of coronary artery spasm in patients with normal coronary angiograms and unexplained ventricular fibrillation

AIMS: The aetiology of ventricular fibrillation in patients without identifiable structural heart disease is unknown. Recently, high prevalence of silent ischaemia due to coronary artery spasm has been reported in such patients. However, in at least one report, all patients had non-critical coronary artery lesions. Identification of coronary artery spasm as the underlying aetiology of ventricular fibrillation has important therapeutic implications. METHODS AND RESULTS: We performed ergonovine provocation tests in 18 patients (14 males, and four females; mean age, 36 years) with documented ventricular fibrillation in the absence of identifiable structural heart disease who had undergone aborted sudden death. In group I (n = 7) ergonovine provocation tests were performed at a mean interval of 31 months (range 21-42 months) after the index episode. These patients had already received an implantable cardioverter defibrillator, after failed electrophysiologically guided antiarrhythmic therapy. In group II (n = 11) the ergonovine provocation test was performed prospectively as part of the diagnostic evaluation. All patients were off antiarrhythmic drugs, calcium entry or beta-adrenoceptor blockers at the time of the ergonovine provocation test. Ergonovine was administered intravenously as a bolus injection, beginning with 0.05 mg followed every 3 min by incremental doses up to a cumulative maximum dose of 0.45 mg. Predefined end-points were (1) recording of ischaemic ST segment shifts of > or = 1 mm in at least two corresponding leads of the 12-lead electrocardiogram; (2) induction of ventricular tachycardia or ventricular fibrillation; and (3) administration of a cumulative dose of 0.45 mg. A positive response to ergonovine was seen in only one patient (5%) in group I in whom there developed ST segment elevation without angina and a short burst of rapid ventricular tachycardia. CONCLUSIONS: This study found a low prevalence of coronary artery spasm in patients with aborted sudden death resulting from documented ventricular fibrillation and non-apparent underlying heart disease. All patients had normal coronary angiograms and a negative history for spontaneous episodes of chest pain. The mechanism of arrhythmogenesis in such patients remains largely unknown.     

A new noninvasive method of diagnosing vasospastic angina based on dilation response of the left main coronary artery to nitroglycerin as measured by echocardiography

OBJECTIVES: The purpose of the present study was to evaluate the feasibility of diagnosing vasospastic angina based on coronary artery tone as assessed by M-mode echocardiographic measurement of the dilation response of the left main coronary artery to nitroglycerin. BACKGROUND: The definite diagnosis of vasospastic angina is done by a coronary spasm provocative test using ergonovine maleate or acetylcholine during cardiac catheterization. Current noninvasive, nonpharmacologic diagnostic methods are not sensitive enough for the diagnosis of vasospastic angina. METHODS: Thirty-eight patients who had an angiographically normal left main trunk were studied. These patients were classified into four groups based on the presence or absence of more than 50% stenosis in the coronary arteries except for the left main trunk and the results of the acetylcholine or ergonovine provocative test. At 7 a.m. and at noon on the same day, the left main trunk diameter was measured by M-mode echocardiography before and after sublingual administration of nitroglycerin (0.3 mg), and its present dilation was calculated to assess coronary artery tone. RESULTS: The percent dilation of the left main trunk diameter induced by sublingual nitroglycerin at 7 a.m. and at noon was 22.4 +/- 4.7% (mean +/- SD) and 18.1 +/- 4.0% in 11 patients with vasospastic angina and without coronary stenosis, 14.9 +/- 7.1% and 11.2 +/- 6.9% in 9 patients with vasospastic angina and coronary stenosis, 6.1 +/- 3.5% and 7.0 +/- 5.1% in 8 patients without vasospastic angina but with coronary stenosis and 8.1 +/- 5.6% and 7.8 +/- 5.7% in 10 control subjects. The percent dilation at 7 a.m. was significantly greater in the vasospastic angina without coronary stenosis group than in the remaining three groups, and in the vasospastic angina groups, the percent dilation at 7 a.m. was significantly greater than that at noon. When percent dilation at 7 a.m. exceeding 15% was defined as positive for the diagnosis of vasospastic angina, the sensitivity was 80% and the specificity 94%. CONCLUSIONS: Basal tone of the left main trunk is elevated in the early morning in vasospastic angina. Dilation of the left main trunk diameter exceeding 15% induced by sublingual nitroglycerin in the early morning as measured by M-mode echocardiography is a highly sensitive and specific criterion for the diagnosis of vasospastic angina.     

Iodine-123-MIBG SPECT versus planar imaging in children with neural crest tumors

Iodine-123-metaiodobenzylguanidine (MIBG) SPECT was compared with 123I-MIBG planar imaging in 35 studies of 25 children with neural crest tumors. METHODS: Iodine-123-MIBG (0.070-0.140 mCi/kg intravenously) was followed at 24 hr by wholebody planar imaging and triple-detector, high-resolution thoraco-abdominal SPECT. At 48 hr, thoracoabdominal planar imaging was performed whenever a high-tissue background or gut activity interfered with the interpretation of the 24-hr planar images. SPECT views included a cine loop presentation of multiple volume-rendered projections. Two reviewers enumerated the number of abnormal sites on the planar and SPECT studies and rated the certainty of interpretation for each study on a scale from 0.1 (low certainty) to 1.0 (high). RESULTS: Abnormal uptake was noted on planar or SPECT imaging in 13 studies (seven patients). The average number of abnormal sites detected per study for all 35 studies was 2.7 for planar imaging and 2.9 for SPECT (p = not significant) (and 7.2 and 8.4 for planar and SPECT, respectively, for the 13 abnormal studies.) The certainty ratings for all 35 studies were 0.74 for planar studies, 0.82 for SPECT (p = 0.05, chi-square, compared with planar) and 0.86 for planar and SPECT combined (p = 0.01 compared with planar alone). On volume-rendered images, gut activity was seen as diffuse and/or linear intraluminal activity. CONCLUSION: When 123I-MIBG SPECT is used, the number of lesions detected is not increased, but there is a significant improvement in the certainty of interpretation over planar imaging.     

Fasting and nonfasting iodine-123-idophenylpentadecanoic acid myocardial SPECT imaging in coronary artery disease

Iodine-123-labeled idophenylpentadecanoic acid (IPPA) metabolic imaging has been shown to be clinically useful for the identification of myocardial viability in patients with coronary artery disease and left ventricular dysfunction. Imaging is usually performed under fasting conditions since nonfasting conditions may affect myocardial uptake of 123I-IPPA. The purpose of this study was to examine the impact of dietary condition on 123I-IPPA metabolic imaging. METHODS: Forty patients with stable coronary artery disease underwent, in randomized order and on separate days, 123I-IPPA SPECT myocardial imaging under fasting and nonfasting conditions. Patients were injected with 123I-IPPA (4-5 mCi) at rest with imaging performed at 4 (initial) and 30 (delay) min. For each image (initial and delay images), 10 segments were analyzed by three experienced observers without knowledge of patient identity or dietary condition using a 5-point grading system (O = no uptake to 4 = normal uptake). A summed global score was obtained for each image by adding the scores for all 10 segments. Image quality was assessed using a 3-point grading system. RESULTS: Visual agreement for normal and abnormal segments between fasting and nonfasting conditions was 82% (kappa = 0.63). There were no significant differences in the summed global scores for both conditions. Image quality was equivalent for both conditions in 65% of cases and superior under the nonfasting condition in 25% of cases. CONCLUSION: Image quality as well as the presence, location and severity of defects are similar under fasting and nonfasting conditions with 123I-IPPA. Therefore, fasting is not necessary before 123I-IPPA SPECT imaging for the assessment of myocardial viability.     

Evaluation of long-term prognosis in patients with heart failure: is cardiac imaging with iodine-123 metaiodobenzylguanidine useful?

The effect of cardiac sympathetic activity on long-term prognosis in patients with heart failure was evaluated by cardiac imaging with iodine-123 metaiodobenzylguanidine (123I-MIBG) in 46 patients admitted for the first episode of heart failure (idiopathic dilated cardiomyopathy: 18, ischemic heart disease: 10, hypertensive heart disease: 7, valvular heart disease: 4, others: 7). Cardiac imaging was performed with 123I-MIBG and thallium-201 (201Tl) at rest on separate days before discharge. Using whole body imaging, the ratio of cardiac uptake of the isotope to total injected dose was calculated (percentage uptake). The cardiac uptake ratio of 123I-MIBG (percentage uptake of 123I-MIBG divided by percentage uptake of 201Tl) and percentage washout of 123I-MIBG from the heart over 3 hours were calculated as scintigraphic parameters. Cardiac events were defined as cardiac death or deterioration of heart failure requiring readmission. Scintigraphic parameters, clinical parameters, left ventricular function obtained by echocardiography and neurohumoral parameters were compared between the event group and event-free group. During the follow-up period of 26.9 +/- 13.9 (7.1-53.8 months), cardiac events developed in 14 patients (cardiac death in 10 and deterioration of heart failure in 4; 30%). Univariate analysis showed uptake ratio and washout rate of 123I-MIBG, percentage uptake of 201Tl, New York Heart Association class at discharge, fractional shortening of the left ventricle, serum norepinephrine and atrial natriuretic peptide levels differed significantly between the two groups. Cox proportional-hazard analysis showed that the uptake ratio was an independent predictor of cardiac events (p < 0.0001). When a cut-off point in the uptake ratio equal to or less than 0.50 and age equal to or more than 65 years old were included in the Cox proportional-hazard analysis instead of actual numbers, relative risks of cardiac events by each index were 31.2 (95% confidence interval, 3.9 to 247.6; p = 0.001) and 4.2 (p = 0.025), respectively. These data suggest that cardiac uptake of 123I-MIBG is a strong and independent predictor of long-term prognosis in patients with heart failure.     

Differential responsiveness of murine T lymphomas to local growth and invasion factors may determine metastasis formation in the ovaries

Iodine-123-metaiodobenzylguanidine [123I-MIBG] has been used to evaluate the cardiac sympathetic nervous system. We evaluated the effect of pulmonary hypertension on the sympathetic neuronal function of the left ventricle in patients with pulmonary hypertension. We studied 20 patients with either chronic lung disease or pulmonary vascular disease. The patients were divided into a pulmonary hypertensive group and a control group. Single photon emission tomography was performed in the resting state 15 min and 4 h after administration of 123I-MIBG. Regions of interest (ROI) were set in the left ventricular (LV) free wall, the interventricular septum (IVS) and outside the LV free wall on short-axis images. The washout rate and the ROI/LV uptake ratio were calculated in each ROI. The IVS:LV uptake ratio was significantly lower in the pulmonary hypertensive group than in the control group. Our results suggest that left heart sympathetic neuronal dysfunction initially occurs in the IVS before it involves the LV free wall subsequently.     

Action of intracoronary nitroglycerin in refractory coronary artery spasm

Coronary artery spasm usually responds to sublingual nitroglycerin. This report describes four patients with variant angina and one patient with rest angina who had coronary spasm that was refractory to sublingual or i.v. nitroglycerin. In four patients, spasm occurred spontaneous and in one patient after 0.05 mg of ergonovine. In each case, 25-100 micrograms of intracoronary nitroglycerin promptly (30-45 seconds) resulted in reopacification of the vessel involved in spasm and resolution of evidence for ischemia. Thus, intracoronary nitroglycerin can reverse coronary artery spasm that does not respond to systemic nitroglycerin administration.     

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.     

Radioimmunotherapy of orthotopically transplanted pancreatic cancer with 131I-labeled chimeric monoclonal antibody Nd2

Recent study demonstrated high susceptibility of plasma LDL to lipid peroxidative modification in patients with variant angina. Oxidized stress state, especially oxidized LDL, may induce coronary artery spasm by its impairing effect of endothelium-dependent arterial relaxation, but precise mechanisms remain unclear. Study subjects included 93 patients who underwent coronary angiographic examination: 12 patients with coronary artery spasm provoked by ergonovine without organic stenosis (group I), 11 patients who did not demonstrate coronary artery spasm or organic stenosis (group II) and 70 patients with organic coronary artery stenosis (group III). Levels of plasma HDL-cholesterol and apoA-I in group I were similar to those in III but were significantly lower than those in II, although the other plasma lipid parameters were not different among the three groups. The levels of TBARS in plasma and HDL were significantly higher in group I than in II or III (2.94+/-1.56 vs. 1.91+/-0.35 or 2.23+/-0.89 nmol MDA/ml and 1.23+/-1.00 vs. 0.54+/-0.37 or 0.70+/-0.63 nmol MDA/mg protein; P < 0.05), although the levels of TBARS in LDL were not significantly different. In the monitoring curve of diene production during copper-induced lipid peroxidation of HDL, its propagation slope was steeper and levels of maximum diene absorbance was higher in group I as compared with that in II or III, but not found in those of LDL. These results suggested that high susceptibility of HDL to lipid peroxidative modification in group I may contribute to the genesis of coronary artery spasm, and oxidized HDL rather than oxidized LDL is more likely to be related to coronary artery spasm.     

Coronary vasoreactivity to ergonovine after angioplasty: difference between the infarct-related coronary artery and the noninfarct-related coronary artery

BACKGROUND: The vasoreactivity after direct percutaneous transluminal coronary angioplasty (PTCA) in patients with previous myocardial infarction remains unknown. We examined the constrictor response to ergonovine of the infarct-related coronary artery in comparison with that of noninfarct-related coronary artery after angioplasty. METHODS: Ergonovine was administered intravenously to 17 patients with previous myocardial infarction (group I) and to 21 patients with stable angina (group II) 1 year after PTCA. The effects of ergonovine on lumen diameter were analysed quantitatively at the PTCA segment, nonPTCA segment (proximal to the PTCA segment), and nonPTCA artery. RESULTS: The ergonovine-induced decrease in minimal lumen diameter at the PTCA segment was significant in group I (decrease from 2.12 +/- 0.56 to 1.39 +/- 0.74 mm, P < 0.01), but not in group II (decrease from 1.60 +/- 0.35 to 1.43 +/- 0.33 mm, NS). Patients in group I showed a constrictor response at the nonPTCA artery (decrease in diameter from 2.54 +/- 0.90 to 1.94 +/- 0.77 mm, P < 0.01), and a tendency to constrict at the nonPTCA segment (2.56 +/- 0.67 to 2.11 +/- 0.66 mm, P = 0.06), whereas those in group II showed no significant constrictor response to ergonovine at any of the three segments examined. The changes in diameter at the three segments in patients in group I were significantly greater than those in group II (all P < 0.01). Subtotal coronary spasm at the PTCA segment was provoked only in three patients in group I (18%). CONCLUSIONS: The constrictor response to ergonovine of the infarct-related coronary artery was enhanced compared with that of the noninfarct-related coronary artery. This difference in coronary vasoreactivity at the angioplasty segment may be due to previous hypersensitivity of the smooth muscle.     

Surgical relevance of diagnostic imaging of abdominal tumors--decision making in pancreatic tumor

1. An association has been reported between QT interval abnormalities and cardiovascular autonomic neuropathy in diabetic patients. The QT interval abnormalities reflect local inhomogeneities of ventricular recovery time and may be related to an imbalance in cardiac sympathetic innervation. Sympathetic innervation of the heart can be visualized and quantified by single-photon emission-computed tomography with m-[123I]iodobenzylguanidine. In this study we evaluated cardiac sympathetic integrity by m-[123I]iodobenzylguanidine imaging and the relationship between both QT interval prolongation and QT dispersion from standard 12-lead ECG variables and m-[123I]iodobenzylguanidine uptake in insulin-dependent diabetic patients. 2. Three patient groups were studied, comprising six healthy control subjects, nine diabetic patients without cardiovascular autonomic neuropathy (CAN-) and 12 diabetic patients with cardiovascular neuropathy (CAN+). Resting 12-lead ECG was recorded for measurement of maximal QT interval and QT dispersion. The QT interval was heart rate corrected using Bazett's formula (QTc) and the Karjalainen approach (QTk). Quantitative measurement (in counts/min per g) and visual defect pattern of m-[123I]iodobenzylguanidine uptake were performed using m-[123I]iodobenzylguanidine single-photo emission-computed tomography. 3. Global myocardial m-[123I]iodobenzylguanidine uptake was significantly reduced in both diabetic patient groups compared with control subjects. The visual defect score of m-[123I]iodobenzylguanidine uptake was significantly higher in CAN+ diabetic patients than in control subjects and in CAN- patients. This score was not significantly different between control subjects and CAN- patients. QTc interval and QT dispersion were significantly increased in CAN+ diabetic patients as compared with control subjects (QTc: 432 +/- 15 ms versus 404 +/- 19 ms, P < 0.05; QT dispersion: 42 +/- 10 versus 28 +/- 8 ms, P < 0.05). QT dispersion was also significantly longer in CAN- diabetic patients than in control subjects (41 +/- 9 ms versus 28 +/- 8 ms, P < 0.05). QTc interval was significantly related to global myocardial m-[123I]iodobenzylguanidine uptake and defect score in diabetic patients (r = -0.648, P < 0.01, and r = 0.527, P < 0.05, respectively). There was no correlation between QT dispersion and both m-[123I]iodobenzylguanidine uptake measures. 4. In conclusion, these findings suggest that m-[123I]iodobenzylguanidine imaging is a valuable tool for the detection of early alterations in myocardial sympathetic innervation in long-term diabetic patients without cardiovascular autonomic neuropathy. Insulin-dependent diabetic patients with cardiovascular autonomic neuropathy have a delayed cardiac repolarization and increased variability of ventricular refractoriness. The cardiac sympathetic nervous system seems to be one of the determinants of QT interval lengthening, but does not appear to be involved in dispersion of ventricular recovery time. It is assumed that QT dispersion is based on more complex electrophysiological mechanisms which remain to be elucidated.     

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.     

Assessment of cardiac toxicity by 123I-MIBG myocardial SPECT in elderly non-Hodgkin lymphoma patients treated with COP-BLAM and G-CSF

COP-BLAM chemotherapy with concomitant G-CSF was performed on patients 65 or older with non-Hodgkin's lymphoma (NHL), and cardiac sympathetic disorders due to the chemotherapeutic agents were studied using 123I-MIBG (metaiodobenzylguanidine) myocardial SPECT (single photon emission CT). The results showed no correlation between the ejection fraction due to echocardiography and the total dose of adriamycin (ADR). However, there was a positive correlation between the total dose of ADR and the washout rate, and the possibility of cardiac sympathetic disorders caused by ADR was suggested.     

Iodine-123 metaiodobenzylguanidine cardiac imaging to identify and localize vasospastic angina without significant coronary artery narrowing

OBJECTIVES: We assessed the ability of iodine-123 metaiodobenzylguanidine (MIBG) imaging to identify and localize coronary spasm and determined the most useful method of MIBG analysis in vasospastic angina without significant coronary narrowing. BACKGROUND: Various noninvasive methods have been used to detect vasospastic angina, but they are not very sensitive in patients with sporadic attacks. MIBG imaging has recently been proposed as a useful tool for detecting vasospastic angina. METHODS: Normal limits of both visual and quantitative analysis of two-dimensional polar maps (bull's-eyes) for MIBG imaging were at first established in 59 normal subjects. For optimal criteria of visual analysis, we established regional differences in abnormal MIBG defect scores. An abnormal region of the bull's-eye was defined as an area > 2 SD below normal. An abnormal regional washout rate was defined as < 0%. Using these criteria, we prospectively evaluated 104 patients with suspected vasospastic angina. Visual, bull's-eye and regional washout rate analyses were compared for overall detection of the disease and for individual vessel involvement. RESULTS: Overall sensitivity by these methods was 30%, 42% and 76%, respectively. Washout rate analysis showed a significantly higher sensitivity than the other two methods. Specificity was 78%, 72% and 87%, respectively. The sensitivity of detecting spasm-induced coronary artery with washout rate analysis was 82% for the left anterior descending (LAD), 76% for the right (RCA) and 69% for the circumflex (Cx) coronary arteries. The sensitivity of visual analysis was 29%, 15% and 35%, respectively; that for bull's-eye analysis was 34%, 54% and 41%, respectively. Washout rate analysis showed a significantly higher sensitivity for LAD spasm than for the other two methods and a higher sensitivity for RCA and Cx spasms than for visual analysis. CONCLUSIONS: Regional washout rate analysis of MIBG imaging is a highly accurate technique for determining the presence and location of coronary artery spasm.