Failure to detect a huge Meckel's diverticulum with abundant ectopic gastric mucosa on gastric mucosal scintigraphy with Tc-99m pertechnetate.
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
N Matsunaga
Publications and source records attributed to N Matsunaga.
Ga-67-avid massive cellulitis within a chronic lymphedematous limb in a survivor of Hodgkin's disease.
Explore the source record for details and available documents.
Acute Disease↗
Potential of Gd-DTPA-mannan liposome particles as a pulmonary perfusion MRI contrast agent: an initial animal study.
UNLABELLED: Suga K, Mikawa M, Ogasawara N, et al. Potential of Gd-DTPA-mannan liposome particles as a pulmonary perfusion MRI contrast agent: An initial animal study. Invest Radiol 2001;36:136-145. RATIONALE AND OBJECTIVES: A paramagnetic, particle-type MR contrast agent, (Gd-diethylenetriamine pentaacetic acid [DTPA]-mannan-cholesterol)-coated liposomes, was designed to localize in the lung by the mechanism of capillary blockade, and the potential of this agent for pulmonary perfusion MRI was experimentally investigated. METHODS: Before and up to 60 minutes after slow injection of this contrast agent, MR images were sequentially acquired at 10-second intervals along the same transaxial plane of the lung by using a gradient-echo pulse sequence with a short echo time of 1.2 ms on a 1.5-T MR scanner. After the minimal dose for obtaining a sufficient lung enhancement effect was determined in five rabbits, the time course of the enhancement effect was evaluated in six dogs by arterial blood gas analysis. The efficacy of MRI for detecting perfusion defects was evaluated in seven other dogs with pulmonary embolism. RESULTS: Normal lungs were dose-dependently enhanced by this agent, and with a 2.0 mL/kg dose, dependent lungs were enhanced by more than 201%, with an average half-life of the enhancement effect of 35.7 +/- 5.3 minutes. With less than this dose (1.0-1.5 mL/kg), all of the embolized lung portions were clearly identified as perfusion defects. The prolonged enhancement effect allowed the acquisition of subsequent multisectional lung images, thus facilitating the assessment of anatomic location and extent of the perfusion defects. The reduction of PaO2 in room air after injection was within 5 mm Hg in both normal and embolized animals. CONCLUSIONS: These initial, experimental results show that paramagnetically labeled liposome particles may be a successful MR contrast agent for pulmonary perfusion imaging.
Animals↗
Perfusion characteristics of oleic acid--injured canine lung on Gd-DTPA--enhanced dynamic magnetic resonance imaging.
RATIONALE AND OBJECTIVES: We conducted an animal study to describe and interpret the perfusion characteristics of oleic acid (OA)-injured lungs on gadopentetate dimeglumine (Gd-DTPA)-enhanced dynamic perfusion magnetic resonance (MR) imaging. METHODS: Fourteen dogs received an intravenous OA infusion in the supine (n = 4), prone (n = 4), and right lateral decubitus (n = 6) positions, and 10 minutes later these animals in the same postures underwent the dynamic MR study. Regional Gd-DTPA kinetics was analyzed by the time-signal intensity (SI) curves and by qualitative functional map images of the mean transit time that was representative of the mean circulation time in the vascular bed and the average cumulative sum of the relative increases in SI representative of Gd-DTPA distribution volume during Gd-DTPA first pass. The results were compared with those in six control animals and in another six animals that underwent the MR study 3 minutes (n = 3) and 60 minutes (n = 3) after OA infusion. The MR findings were correlated with the distribution of lung damage and the infused OA particles as assessed by histology. RESULTS: The dynamic MR study showed postural shifts on the gravity-dependent perfusion map of normal lungs. Contrast enhancement during Gd-DTPA first pass in the lung was lower and more heterogeneous in the OA-injured lung models than in controls but was followed by conversely greater and persistent enhancement during the Gd-DTPA redistribution phase. Regardless of the postures for OA infusion, these abnormalities were predominant in the dependent lungs and became more pronounced with time after OA infusion, where more prominent capillary obstruction with OA droplets and alveolar/interstitial edema were histologically observed. On the functional map images, greater mean transit time and the average cumulative sum of the relative increases in SI values were also predominantly distributed in the dependent lungs. CONCLUSIONS: Low and heterogeneous enhancement was observed during Gd-DTPA first pass but was followed by persistent enhancement during the Gd-DTPA redistribution phase, and predominant abnormalities in the dependent lungs may be characteristic features of the perfusion of OA-injured lungs. The histological correlations indicate that these abnormalities may reflect OA-induced pathophysiologies associated with capillary OA obstruction, increased vascular resistance, and capillary permeability/extravascular spaces and that lung damage may be gravity dependent.
Animals↗
Functional assessment of canine kidneys after acute vascular occlusion on Gd-DTPA-enhanced dynamic echo-planar MR imaging.
RATIONALE AND OBJECTIVES: To assess the alteration in renal transit of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) in dog kidneys after acute vascular occlusion on dynamic echo-planar imaging (EPI). METHODS: Dynamic 240-ms EPI series (repetition time/echo time/inversion time [TR/TE/TI] = 3000/42.1/100 ms) of the midcoronal plane of both kidneys of dogs anesthetized by intravenous administration of phenobarbital sodium and ketamine hydrochloride were obtained before and after ligation of the left renal vein (n = 6) or artery (n = 6) for 40 minutes after a 2-second-rate bolus injection of a 0.05 mmol/kg dose of Gd-DTPA. Renal Gd-DTPA transit was analyzed on the time-DeltaR2* curves in each layer of the outer cortex (OC), juxtamedullary cortex and outer zone of the medulla (JMC-OM), and the inner zone of the medulla (IM). The results were compared with those in six normal animals and those of a fast gradient-echo T1-weighted dynamic study performed in other vein- (n = 6) or artery- (n = 6) occluded animals and six normal animals. The histopathological basis of the altered Gd-DTPA transit was also evaluated. RESULTS: The dynamic EPI showed rapid Gd-DTPA transit through each of the five concentric layers, with three separate peaks on the time-DeltaR2* curves. The vein-occluded kidneys showed immediate swelling, with a significant increase in the cross-sectional area proportion of the JMC-OM layer compared with normals (32% +/- 2% vs 24% +/- 2%, P < 0.0001) and intensely congested capillaries, tubular, obliterated material, and gradual and persistent enhancement of the OC and JMC-OM layers but poor Gd-DTPA migration to the IM layer. The artery-occluded kidneys showed a significant reduction in the entire cross-sectional area compared with normals (1352 +/- 69 vs 1432 +/- 47 mm(2), P < 0.05) and poor enhancement, with significant decreases in the area under the time-DeltaR2* curve of the OC and JMC-OM layers compared with the vein-occluded kidneys (79 +/- 50 vs 324 +/- 108 and 82 +/- 42 vs 326 +/- 113, respectively; both P < 0.0001), despite minimal histological damage. In both models, the nonaffected kidneys showed significant increases in the area under the time-DeltaR2* curves compared with baseline. The time course of vascular and tubular Gd-DTPA transit was more detailed by the EPI study than by the T1-weighted imaging study. CONCLUSIONS: Echo-planar imaging has an excellent ability to follow the rapid, renal Gd-DTPA transit through the regional anatomy of the canine kidney. After venous occlusion, the JMC-OM layer may be the most affected site, primarily causing renal swelling and interruption of tubular Gd-DTPA transit and concentration. In contrast, an initial block of vascular Gd-DTPA inflow is the primary effect of arterial occlusion. Nonaffected kidneys seem to compensate by increasing excretion of Gd-DTPA.
Acute Disease↗
Histopathological examination of two cases of anterior staphyloma associated with Peters' anomaly and persistent hyperplastic primary vitreous.
AIMS: To clarify the developmental mechanism and critical period for the uncommon complex of Peters' anomaly and persistent hyperplastic primary vitreous (PHPV). METHODS: Two eyes with Peters' anomaly and PHPV were histologically examined by serial section. One eye was enucleated at age 7 months (case 1) and the other at age 4 months (case 2) owing to severe anterior staphyloma. RESULTS: In both eyes, defects in the endothelium, Descemet's membrane, and posterior stroma were observed in the central cornea, and the degenerative lens adhered to the posterior surface of the defective corneal stroma. Also, in both eyes, the anterior chamber space was not formed and the undifferentiated iris stroma adhered to the posterior surface of the peripheral cornea. Mesenchymal tissue containing melanocytes was observed behind the degenerative lens, and the pigment epithelium was absent at the lower nasal side of the ciliary body in case 1. In case 2, mesenchymal tissue containing scattered melanocytes in the vitreous cavity was seen on the posterior retina. Based on the histological findings, both cases were diagnosed as Peters' anomaly caused by the faulty separation of the lens vesicle, PHPV, maldevelopment of the iris and ciliary body, and goniodysgenesis. CONCLUSION: Migratory disorders of neural crest cells from 4 to 7 weeks of gestation may be responsible for various ocular anomalies including Peters' anomaly and PHPV, as observed in these cases.
Abnormalities, Multiple↗
The substituent effect on nonlinear current voltage characteristics in a two-terminal molecular electronic device.
We present a quantum mechanical tunneling model for electron transport through a molecular junction and address the model with the results of quantum chemical electronic structure calculations. The model gives insight into the origin of the substituent effect on the current versus applied voltage characteristics of molecular junctions.
Computer Simulation↗
Application of the PKCYP-test in cases of altered CYP1A2 for multiple CYP systems in rat models of disease.
Previously, we established a method to assess drug metabolism capacity based on a pharmacokinetic estimation of the quantity of cytochrome P450 (CYP) in vivo (PKCYP-test) by introducing an apparent liver-to-blood free concentration gradient in vivo (qg). The qg values were determined as the ratio of in vivo-in vitro clearance. In this study, we examined the application of the PKCYP-test to the clearance of acetanilide and caffeine mediated by CYP1A2 using rat models in which the levels of CYP enzymes were reduced. Rats fed a choline-deficient diet (CD-fed) and aged rats were used as models for a low level of CYP in the liver. In both rat models, the contribution (fCYP) of CYP1A2 to the in vivo intrinsic clearance values (CLint) of acetanilide and caffeine metabolism was less than unity, suggesting that other metabolic pathways are involved in the CLint. The in vivo clearance for CYP1A2 was estimated by multiplying fCYP by CLint, then the value of qg was determined as the ratio of in vivo-in vitro clearance. We predicted the level of CYP1A2 in CD-fed and aged rats, based on the clearance of acetanilide mediated by CYP1A2, using the qg value of control rats. The clearance of caffeine mediated by CYP1A2 in CD-fed and aged rats, as estimated from the predicted level of CYP1A2, correlated with the observed values. In conclusion, we have demonstrated that the PKCYP-test can be applied to CYP1A2 for drugs metabolized by multiple CYP isozymes, and/or to models involving reduced CYP.
Acetanilides↗
Application of the PKCYP-test to predict the amount of in vivo CYP2C11 using tolbutamide as a probe.
Previous reports have shown that the determination of drug metabolism capacity can be made by the pharmacokinetic estimation of the quantity of cytochrome P450 (CYP) in vivo (PKCYP-test), in which an apparent liver-to-blood free concentration gradient in vivo (qg) is introduced, which is useful for evaluating fluctuations of CYPIA2 in rats. The aim of the present study was to examine the application of the PKCYP-test to evaluate the quantity of in vivo CYP2C11 by using tolbutamide as a probe, to confirm its validity using a physiologically-based pharmacokinetic rat model. Rats treated with carbon tetrachloride (CCl4-treated rats) were used as a model for low levels of CYP2C11 in the liver. In CCl4-treated rats, the total body clearance (CLtot) of tolbutamide and the amount of CYP2C11 fell to about a quarter and a third of that in control rats, respectively. The time-course of tolbutamide concentrations in serum in control rats could be simulated by a physiologically-based pharmacokinetic model. In CCl4-treated rats, take into consideration the qg value of control rats, the level of CYP2C11 was accurately predicted by the PKCYP-test, and the time-course of tolbutamide concentrations in serum could be predicted by the same physiologically-based pharmacokinetic model. In conclusion, we have shown that the PKCYP-test can be used to predict levels of CYP2C11. It was also demonstrated that the qg and amount of CYP are useful parameters in the PKCYP-test by constructing a physiologically-based pharmacokinetic model which was applied to the PKCYP-test.
Animals↗
Intralobar bronchopulmonary sequestration: evidence of air trapping shown by dynamic xenon-133 SPECT.
Dynamic single photon emission computed tomography with xenon-133 gas in a 29-year-old male patient showed xenon-133 retention within an intralobar bronchopulmonary sequestration (BPS) with a focal hyperlucent lung area on CT. Left lower lobectomy showed no fistulous connection between the anomalous and normal bronchial trees, but non-contiguous, incompletely developed visceral pleura between the sequestration and the adjacent normally ventilated lung. These features strongly support the role of intralobar collateral air drift and air trapping in producing secondary changes of a focal hyperlucent lung area in BPS.
Adult↗
Unenhanced CT findings of vascular compromise in association with intussusceptions in adults.
OBJECTIVE: The purpose of this study was to evaluate unenhanced CT findings for predicting the degree of vascular compromise in intussusception observed at surgery. MATERIALS AND METHODS: The imaging studies, clinical records, and surgical and pathologic findings in 25 patients with intussusception were reviewed retrospectively. We evaluated six CT findings based on the abnormalities of each component of intussusception. Presence or absence of these findings was compared with the degree of vascular compromise as observed on pathologic examination, such as edema, ischemia, or necrosis. RESULTS: The hypodense layer was observed in 16 of 18 intussusceptions with various degrees of vascular compromise. A fluid collection surrounded by the returning wall, which was revealed to correspond to trapped peritoneal fluid, was observed in eight of nine intussusceptions with ischemia or necrosis. A gas collection surrounded by the returning wall was observed in two of four intussusceptions with necrosis. Free peritoneal fluid coexisted with a fluid collection surrounded by the returning wall in all the intussusceptions except one. Bowel obstruction was observed in six of nine intussusceptions with ischemia or necrosis. The maximum wall thickness was not related to the degree of vascular compromise. CONCLUSION: The CT findings of a hypodense layer in the returning wall, fluid collection in the space surrounded by the returning wall, and gas collection in the space surrounded by the returning wall can be useful in predicting the degree of vascular compromise in intussusception.
Adolescent↗
Detection of malignant hepatic tumors: comparison of gadolinium-and ferumoxide-enhanced MR imaging.
OBJECTIVE: The purpose of our study was to compare how well gadolinium-enhanced and ferumoxide-enhanced MR imaging reveal malignant hepatic tumors. SUBJECTS AND METHODS: Both gadolinium-enhanced and ferumoxide-enhanced MR imaging were separately performed in 53 patients with a total of 87 malignant hepatic tumors (57 hepatocellular carcinomas, 28 metastases, two cholangiocarcinomas). Thirty-one of the 53 patients had hepatic cirrhosis. Images were reviewed by three independent off-site observers. Observer performance was evaluated by means of sensitivity, specificity, and receiver operating characteristic curve analyses. RESULTS: Gadolinium-enhanced MR imaging outperformed ferumoxide-enhanced MR imaging in sensitivity (81% versus 62%, p < 0.01) for malignant-tumor detection. Specificity was comparable (94%) between the two types of MR imaging. Area under receiver operating characteristic curve (A(z)) value was significantly higher with gadolinium-enhanced MR imaging than with ferumoxide-enhanced MR imaging in patients overall (A(z) = 0.896 versus 0.805, p < 0.001), in patients with cirrhosis (A(z) = 0.907 versus 0.807, p < 0.001), and in patients without cirrhosis (A(z) = 0.899 versus 0.834, p < 0.01). The superiority was enhanced in the subset of patients with cirrhosis. CONCLUSION: Gadolinium-enhanced MR imaging outperforms ferumoxide-enhanced MR imaging in revealing malignant hepatic tumors. Gadolinium-enhanced MR imaging is recommended, particularly for patients with cirrhosis.
Aged↗
Early retardation of 99mTc-DTPA radioaerosol transalveolar clearance in irradiated canine lung.
UNLABELLED: The alteration of 99mTc-labeled diethylenetriaminepentaacetic acid (DTPA) transalveolar clearance in an initial phase of radiation lung injury was experimentally investigated. METHODS: Fourteen dogs were irradiated to the hemithorax with a single dose of 20 Gy. A DTPA radioaerosol study was performed before irradiation and on day 12 after irradiation. On day 14, the DTPA study was repeated again, with seven animals undergoing the study after inhalation of an aerosolized synthetic surfactant. The penetration index (P.I.) and clearance half-time (T(1/2)) of DTPA were measured in each lung. To evaluate the changes in lung surfactant after irradiation, alveolar lipids were stained in the resected lungs (n = 14), and the amounts of alveolar surfactant phospholipid and protein were measured by a bronchoalveolar lavage study in another six irradiated dogs. RESULTS: In all of the 14 irradiated animals, DTPA radioaerosol distributed uniformly throughout the lungs without significant changes in P.I. The T(1/2) values in irradiated lungs were significantly prolonged compared with the matched baseline values and those in nonirradiated lungs (P < 0.05 and 0.001, respectively). The aerosolized synthetic surfactant retarded the DTPA clearance both in the irradiated and in the nonirradiated lungs (P < 0.001) without significant changes in P.I. The histologic and bronchoalveolar lavage studies revealed an increase of alveolar surfactant materials in the irradiated lungs without substantial histologic changes in the alveolar structures. CONCLUSION: DTPA transalveolar clearance was retarded soon after irradiation. Increased alveolar surfactant may be partly responsible for this retarded DTPA clearance because the aerosolized synthetic surfactant also prolonged the clearance in nonirradiated lungs. A DTPA clearance test is sensitive for the early detection of radiation lung injury and seems helpful for clarifying the association of epithelial integrity changes and lung surfactant in radiation lung injury.
Administration, Inhalation↗
Reduction in tick numbers (Haemaphysalis longicornis), mortality and incidence of Theileria sergenti infection in field-grazed calves treated with flumethrin pour-on.
The effectiveness of the pour-on formulation of flumethrin was tested on grazing cattle. Flumethrin was applied once a month from April to October from 1990 to 1995 to cattle grazing in the Aso area of Kumamoto Prefecture in Japan. Both the number of ticks in the field and the number of ticks feeding on cattle decreased remarkably in relation to the number of years flumethrin was applied. Ticks in the field were not detected in 1994 and 1995, and ticks feeding on cattle decreased to 4% in 1995. Mortality due to Theileria sergenti infection also decreased significantly after more than 3 years of flumethrin pour-on application, although overall mortality did not change. At the end of the trial the incidence of T. sergenti had decreased to one-fifth of the pretrial value, although total incidence of disease had not changed. These results indicated that multiple-year seasonal application of flumethrin pour-on to grazing cattle effectively decreased the number of ticks and decreased both mortality and incidence of T. sergenti.
Administration, Topical↗
In situ localization of agouti signal protein in murine skin using immunohistochemistry with an ASP-specific antibody.
Switching between production of eumelanin or pheomelanin in follicular melanocytes is responsible for hair color in mammals; in mice, this switch is controlled by the agouti locus, which encodes agouti signal protein (ASP) through the action of melanocortin receptor 1. To study expression and processing patterns of ASP in the skin and its regulation of pigment production in hair follicles, we have generated a rabbit antibody (termed alphaPEP16) against a synthetic peptide that corresponds to the carboxyl terminus of ASP. The specificity of that antibody was measured by ELISA and was confirmed by Western blot analysis. Using immunohistochemistry, we characterized the expression of ASP in the skin of newborn mice at 3, 6, and 9 days postnatally. Expression in nonagouti (a/a) black mouse skin was negative at all times examined, as expected, and high expression of ASP was observed in 6 day newborn agouti (A/+) and in 6 and 9 day newborn lethal yellow (A(y)/a) mouse skin. In lethal yellow (pheomelanogenic) mice, ASP expression increased day by day as the hair color became more yellow. These expression patterns suggest that ASP is delivered quickly and efficiently to melanocytes and to hair matrix cells in the hair bulbs where it regulates melanin production.
Agouti Signaling Protein↗
Phantom study of fusion image of CT and SPECT with body-contour generated from external Compton scatter sources.
PURPOSE: A phantom study was conducted to evaluate the feasibility of body contour definition with Compton scatter photons from external sources of technetium-99m pertechnetate (Tc-99m) to create a fusion image of CT and SPECT images. METHODS: External sources of 1 mCi (37 MBq) Tc-99m were placed on each collimator, and body-contour SPECT images were obtained with an energy window of 100 keV +/- 25% for detecting 90 degrees and 180 degrees Compton scatter photons of Tc-99m from the body surface in water-filled cylindrical and hexagonal phantoms, and in a chest phantom with a Tc-99m-avid simulated lung nodule and multimethod surface markers. In the chest phantom, each transaxial SPECT slices was registered with the corresponding CT slice by using image-matching soft ware. A summation of the registered images yielded a three-dimensional (3-D) fusion image of this phantom. RESULTS: This method clearly visualized the body contour on all the SPECT slices in all the phantoms except for the complex hexagonal phantom. There was no significant difference between the known and SPECT-measured diameters of the cylindrical phantom. The fit of CT and SPECT images of the chest phantom was achieved with a mean alignment error of 5% in visual inspection, which was improved to 0.2% after correction of the magnification of the SPECT images according to the resultant dimensional differences. The 3-D fusion image of this phantom effectively visualized the anatomic location of the lung nodule and surface markers. CONCLUSION: This simple method effectively provided boundary information on the cold phantoms. Although further improvements in the registration technique with CT images are desirable, the body-contour SPECT image obtained by this method has the potential for accurately creating a 3-D fusion image with CT images, and is a feasible way of anticipating the anatomical localization of a target tissue.
Humans↗
Relative preservation of peripheral lung function in smoking-related pulmonary emphysema: assessment with 99mTc-MAA perfusion and dynamic 133Xe SPET.
In this study the cross-sectional functional differences between the central and peripheral lung in smokers with pulmonary emphysema were evaluated by lung perfusion and dynamic xenon-133 single-photon emission tomography (SPET). The subjects were 81 patients with a long-term smoking history and relatively advanced emphysema, 17 non-smoker patients with non-obstructive lung diseases and six healthy non-smokers. Regional lung functional difference between the peripheral and central lung was assessed in the upper, middle and lower lung zones by technetium-99m macroaggregated albumin SPET and dynamic 133Xe SPET. The distribution of emphysematous changes was assessed by density-mask computed tomography (CT) images which depicted abnormally low attenuation areas (LAAs) of less than -960 Hounsfield units. Two hundred and eighty-eight (59.2%) lung zones of 63 (77.7%) patients with pulmonary emphysema showed relative preservation of lung function in the peripheral lung, with a curvilinear band of normal perfusion (a stripe sign) and a significantly faster 133Xe half-clearance time (T(1/2)) than in central lung (P<0.0001). Of these lung zones, 256 (88.8%) showed central-dominant LAA distributions on density-mask CT images, but the remaining 32 zones did not show any regional preference in LAA distribution. Conversely, 117 (24.0%) lung zones of 19 (23.4%) patients showed periphery-dominant perfusion defects and LAA distributions, with significantly prolonged T(1/2) in the peripheral lung area (P<0.0001). The remaining 81 lung zones of the patients with pulmonary emphysema and all the lung zones of the healthy subjects and patients with non-obstructive lung diseases did not show a stripe sign, and no differences were observed in T(1/2) values and LAA distributions between the central and peripheral lung. Relative preservation of peripheral lung function seems to be a characteristic feature in smoking-related pulmonary emphysema, and may indicate a lower susceptibility of peripheral parenchyma to the development of this disease.
Case-Control Studies↗
Alteration of myocardial metaiodobenzylguanidine uptake after treatment of phaeochromocytoma and neuroblastoma.
The relationships between changes in myocardial uptake of metaiodobenzylguanidine (MIBG) and those in circulating catecholamines and cardiac function after treatment of phaeochromocytoma and neuroblastoma were evaluated. Iodine-123 or iodine-131 MIBG scintigraphy was performed before and after surgical resection and/or chemotherapy for primary tumours in nine patients with phaeochromocytoma and 13 patients with neuroblastoma. Changes in myocardial MIBG uptake after treatment were estimated by the heart-to-upper mediastinum (H/M) uptake ratios on the images obtained 24 h after MIBG injection, which were compared with serum levels of noradrenaline (NA) and adrenaline (A). Cardiac function was assessed by echocardiography, with measurements of the left ventricular ejection fraction (LVEF). Before treatment, eight patients with phaeochromocytoma and three with neuroblastoma showed poor myocardial MIBG uptake, with highly elevated circulating NA and A. Echocardiography, however, did not show cardiac dysfunction in these patients with the exception of two patients with phaeochromocytoma. With normalization of NA and A levels after treatment, all of these patients except for the two with persistent cardiac dysfunction showed restoration of myocardial MIBG uptake. The H/M ratios increased significantly after treatment in both patient groups, i.e. with phaeochromocytoma and with neuroblastoma (P<0.0001 and P<0.05, respectively), and these ratios correlated inversely with circulating NA and A before and after treatment. By contrast, there was no significant correlation between H/M ratios and LVEF in these two groups. These results indicate that suppression of myocardial MIBG uptake usually may not be related to cardiac dysfunction and may be reversible following normalization of excess catecholamine levels after treatment in patients with neuroadrenergic tumours. However, the suppression may persist in the presence of catecholamine-induced cardiac dysfunction. The assessment of myocardial MIBG uptake can be a helpful adjunct in monitoring the normalization of circulating catecholamine levels and also in identifying the presence of cardiac dysfunction in treated patients with neuroadrenergic tumours.
3-Iodobenzylguanidine↗