Impaired cardiac sympathetic innervation activity is associated with myocardial extracellular remodeling, functional capacity and biomarkers

Background

Despite recent advances in treatment, heart failure (HF) continues to be associated with high mortality rates. In this setting, 123iodine-meta-iodobenzylguanidine (123I-MIBG) scintigraphy emerges as a promising tool for the prediction of clinical outcomes in HF due to its ability to assess cardiac sympathetic innervation. However, 123I-MIBG scintigraphy's correlation with myocardial remodeling and cardiopulmonary exercise capacity has not yet been fully elucidated.

Objectives

To evaluate cardiac sympathetic activity through 123I-MIBG scintigraphy, and to analyze its correlation with myocardial remodeling and exercise capacity in HF patients.

Methods

Symptomatic HF patients (NYHA class II–III) stratified by LVEF as HFpEF (LVEF 45%) and HFrE'F (LVEF <45%) and healthy controls were enrolled. HF patients were euvolemic under optimized treatment at the time of enrollment. All individuals underwent CMR with morphology/function and extracellular volume fraction (ECV) assessment, global longitudinal strain (GLS) by echocardiogram, cardiopulmonary exercise testing (CPET), cardiac sympathetic imaging 123I-MIBG scintigraphy (mIBG), and NT-proBNP.

Results

Eighty individuals were recruited allocated into the following groups: HFpEF (n=33, 59.42±12.63 years, LVEF: 59.82±9.87, NT-proBNP: 409.40±693.37, H2FPEF-score: 5±2), HFrEF (n=28, 53.93±11.40 years; LVEF: 29.81±8.67, NT-proBNP: 1662,34±2016,73) and healthy controls (42.65±13.96 years, LVEF: 65.27±4.73, NT-proBNP: 44,43±33,28) were enrolled. While ECV was elevated in HF groups (HFpEF: 0.32±0.05%, HFrEF: 0.31±0.41% and controls: 0.26±0.03, p<0.05), adjusted maximum oxygen consumption (VO2max) was markedly reduced vs. controls (HFpEF: 18.58±6.29mL/kg/min, HFrEF: 17.60±3.89mL/kg/min, controls: 29.73±9.98mL/kg/min, p<0.001). The MIBG heart-to-mediastinum ratio at 4 hours (H/M) was significantly lower in HF compared with controls (HFpEF: 1.59±0.25, HFrEF: 1.45±0.15 and controls: 1.92±0.25, p<0.001). Interestingly, the H/M ratio was more impaired with HFrEF compared to HFpEF (Fig. 1A). As a result, the mean myocardial washout rate was increased in HF patients (HFrEF 36.38±14.35, HFpEF 29.92±18.33 vs. controls 8.0±27.01, p<0.001). In addition, considering all HF patients, H/M was inversely associated with ECV (R: −0.45, p<0.001, Fig. 1B), NT-proBNP (R: −0.55, p<0.001) and VO2max (R: −0.27, p: <0.024, Fig. 1C). GLS was inversely associated with H/M in HFrEF but not HFpEF (HFrEF: R: −0.535, p<0.001 and HFpEF: R: −0.036, p=NS, Fig. 1D).

Conclusion

Cardiac sympathetic activity assessed by 123I-MIBG was abnormal in patients with HF with reduced and preserved EF as compared to controls. H/M, a validated marker for cardiac sympathetic activity, showed a strong correlation with markers of functional capacity and myocardial remodeling. Sympathetic innervation appears to be a limiting factor for global longitudinal strain in HFrEF, while in HFpEF longitudinal strain is independent of sympathetic activity

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): The São Paulo Research Foundation

Comparison of estimates of body fat content in childhood-onset systemic lupus erythematosus

Objective We aimed to compare estimates of body fat content with respect to their ability to predict the percentage of body fat, confirmed by dual-energy X-ray absorptiometry scans in childhood-onset systemic lupus erythematosus. Methods We included 64 consecutive childhood-onset systemic lupus erythematosus patients and 64 healthy age and sex-matched controls in a cross-sectional study. Anthropometric data, body mass index and body adiposity index were calculated for all subjects. Childhood-onset systemic lupus erythematosus patients were further assessed for clinical and laboratory childhood-onset systemic lupus erythematosus manifestations and fat mass, lean mass and percentage of body fat evaluated by dual-energy X-ray absorptiometry. Results Elevated waist/hip ratio was observed in childhood-onset systemic lupus erythematosus patients when compared to controls ( p < 0.001). We did not find differences between body mass index and body adiposity index classification in childhood-onset systemic lupus erythematosus patients and controls. Using dual-energy X-ray absorptiometry as gold standard we observed that all indirect estimates of body fat were correlated with whole body fat mass. We observed a correlation between height and cumulative corticosteroid dose adjusted by weight ( r = 0.429, p = 0.005) in childhood-onset systemic lupus erythematosus. On whole body analysis we observed a correlation between lean mass and ACR Damage Index scores ( r = -0.395; p = 0.019); percentage of body fat and adjusted Systemic Lupus Erythematosus Disease Activity Index ( r = 0.402; p = 0.008), disease duration ( r = -0.370; p = 0.012). On trunk analysis we observed a correlation between lean mass and ACR Damage Index ( r = -0.319; p = 0.042); percentage of body fat with adjusted Systemic Lupus Erythematosus Disease Activity Index ( r = 0.402; p = 0.005), disease duration ( r = -0.408; p = 0.005). Conclusions This is the first study analyzing body adiposity index in childhood-onset systemic lupus erythematosus patients. We observed that all indirect estimates of body fat were correlated with whole body fat mass. This study shows that we should not replace body mass index by body adiposity index to evaluating fat levels in childhood-onset systemic lupus erythematosus. In consideration of the importance of overweight classification in cardiovascular diseases, any direct estimates of body fat can be used in an attempt to improve the prognosis of patients. Note We believe that we have presented evidence of body adiposity index accuracy in childhood-onset systemic lupus erythematosus patients but further research on the generalizability of body adiposity index to other patient groups needs to be done.

Attenuation correction effects on SPECT/CT procedures: phantoms studies

Attenuation correction is widely used in SPECT/CT (Single Photon Emission Computed Tomography) procedures, especially for imaging of the thorax region. Different compensation methods have been developed and introduced into clinical practice. Most of them use attenuation maps obtained using transmission scanning systems. However, this gives extra dose of radiation to the patient. The purpose of this study was to identify when attenuation correction is really important during SPECT/CT procedures.For this purpose, we used Jaszczak phantom and phantom with three line sources, filled with technetium ((99m)-Tc), with scattering materials, like air, water and acrylic, in different detectors configurations. In all images acquired were applied analytic and iterative reconstruction algorithms; the last one with or without attenuation correction. We analyzed parameters such as eccentricity, contrast and spatial resolution in the images.The best reconstruction algorithm on average was iterative, for images with 128 × 128 and 64 × 64 matrixes. The analytical algorithm was effective only to improve eccentricity in 64 × 64 matrix and matrix in contrast 128 × 128 with low statistics. Turning to the clinical routine examinations, on average, for 128 × 128 matrix and low statistics counting, the best algorithm was the iterative, without attenuation correction,improving in 150% the three parameters analyzed and, for the same matrix size, but with high statistical counting, iterative algorithm with attenuation correction was 25% better than that without correction. We can conclude that using the iterative algorithm with attenuation correction in the water, and its extra dose given, is not justified for the procedures of low statistic counting, being relevant only if the intention is to prioritize contrast in acquisitions with high statistic counting.

Quantitative coronary arterial stenosis assessment by multidetector CT and invasive coronary angiography for identifying patients with myocardial perfusion abnormalities

BACKGROUND

Semi-quantitative stenosis assessment by coronary CT angiography only modestly predicts stress-induced myocardial perfusion abnormalities. The performance of quantitative CT angiography (QCTA) for identifying patients with myocardial perfusion defects remains unclear.

METHODS

CorE-64 is a multicenter, international study to assess the accuracy of 64-slice QCTA for detecting ≥50% coronary arterial stenoses by quantitative coronary angiography (QCA). Patients referred for cardiac catheterization with suspected or known coronary artery disease were enrolled. Area under the receiver-operating-characteristic curve (AUC) was used to evaluate the diagnostic accuracy of the most severe coronary artery stenosis in a subset of 63 patients assessed by QCTA and QCA for detecting myocardial perfusion abnormalities on exercise or pharmacologic stress SPECT.

RESULTS

Diagnostic accuracy of QCTA for identifying patients with myocardial perfusion abnormalities by SPECT revealed an AUC of 0.71, compared to 0.72 by QCA (P = .75). AUC did not improve after excluding studies with fixed myocardial perfusion abnormalities and total coronary arterial occlusions. Optimal stenosis threshold for QCTA was 43% yielding a sensitivity of 0.81 and specificity of 0.50, respectively, compared to 0.75 and 0.69 by QCA at a threshold of 59%. Sensitivity and specificity of QCTA to identify patients with both obstructive lesions and myocardial perfusion defects were 0.94 and 0.77, respectively.

CONCLUSIONS

Coronary artery stenosis assessment by QCTA or QCA only modestly predicts the presence and the absence of myocardial perfusion abnormalities by SPECT. Confounding variables affecting the relationship between coronary anatomy and myocardial perfusion likely account for some of the observed discrepancies between coronary angiography and SPECT results.

Decrease in bone mass in women after liver transplantation: associated factors

BACKGROUND

In the future, an increasing number of female liver transplant recipients will reach the climacteric with osteoporosis as a common complication. We evaluated the factors associated with decreased bone mass among women after liver transplantation.

METHODS

A prospective, cross-sectional study of 23 outpatient transplant recipients followed from February 2009 to March 2010 included women of age ≥35 years after liver transplantations ≥1 year prior. We recorded patient histories, liver enzyme levels, as well as bone mineral densities measured at the lumbar spine and femur. Statistical analysis used Fisher's exact test, simple odds ratio (OR), and Spearman's rank correlation coefficient.

RESULTS

The mean patient age was 52.5 ± 11 years with 30.4% premenopausal, and 69.6% perimenopausal or postmenopausal. Approximately 21% showed osteoporosis and 35%, a low bone mass. Postmenopausal women: OR 69.0 (95% CI 2.89-1647.18; P<.0001), aged ≥49 years: OR 13.33 (95% CI 1.78-100.15; P=.0123) and receiving a transplant after 44 years of age: OR 49.50 (95% CI 3.84-638.43; P<.0001) were associated with a lower bone mass. Having undergone transplantation for more than 5.8 years lowered the risk of bone mass change: OR 0.11 (95% CI 0.02-0.78; P=.0361). Clinical and laboratory variables, including corticosteroid use, were not associated with decreased bone mass.

CONCLUSION

Understanding the prevalence and factors associated with osteoporosis among female liver transplant recipients is important to enhance the strategies to diagnose and treat these women, seeking to improve their quality of life.

Voxel-based morphometry of brain SPECT can detect the presence of active central nervous system involvement in systemic lupus erythematosus

OBJECTIVE

To determine the value of voxel-based morphometry (VBM) of brain SPECT (single-photon emission computed tomography) images (BSI) in discriminating active central nervous system (CNS) manifestations in systemic lupus erythematosus (SLE) patients.

PATIENTS AND METHODS

Forty SLE patients (mean age 33 yrs) and 33 normal volunteers were submitted to BSI. SLE patients were screened for the presence of CNS involvement following the American College of Rheumatology (ACR) case definition. Patients with CNS infections, uraemia, diabetes and previous ischaemic or haemorrhagic stroke were excluded. Magnetic resonance imaging (MRI) scans were obtained in a 2T scanner (Elscint Prestige) with T1- and T2-weighted images. BSI were performed after injection of 1110 MBq (30 mCi) of (99m)Tc-ECD (ethyl-cysteinate-dimer). BSI were analysed using the statistical parametric mapping. After normalization, segmentation and smoothing the groups of SLE patients with active and inactive CNS manifestations and healthy volunteers were compared using VBM. Post-processed images were compared voxel-by-voxel using t-test in order to determine differences of intensity between groups. This analysis included grand mean scaling, proportional threshold masking (set to 0.4) and implicit masking. A P-value of 0.001 and cluster size of 32 were taken into consideration.

RESULTS

VBM analyses of BSI did not show any differences between SLE patients with inactive CNS involvement and normal controls. However, the group of SLE patients with active CNS involvement had a global hypoperfusion, more intense in the frontal, dorsolateral and medial temporal lobe when compared with SLE patients without CNS involvement (P = 0.001) and healthy volunteers (P = 0.001).

CONCLUSION

VBM of BSI is a useful and objective method for detecting perfusion abnormalities in SLE patients, which is indicative of active CNS involvement. However, it is not helpful in differentiating the clinical sub-types of CNS involvement according to the ACR classification.

99mTc-sestamibi thyroid uptake in euthyroid individuals and in patients with autoimmune thyroid disease

PURPOSE

We investigated the biokinetics of (99m)Tc-sestamibi in the thyroid of euthyroid volunteers (EVs) and in patients with autoimmune thyroid diseases and determined the best time interval between (99m)Tc-sestamibi injection and calculation of uptake.

METHODS

Forty EVs, 30 patients with Graves' disease (GD), 15 patients with atrophic Hashimoto's thyroiditis (AHT) and 15 patients with hypertrophic Hashimoto's thyroiditis (HHT) underwent (99m)Tc-sestamibi thyroid scintigraphy. Dynamic images were acquired for 20 min, and static images were obtained 20 min, 60 min and 120 min post injection. Five-, 20-, 60- and 120-min uptake, time to maximal uptake (T(max)) and T(1/2) of tracer clearance were calculated. Thyroid hormones and antibodies were measured. (99m)Tc-pertechnetate uptake was investigated in GD patients.

RESULTS

T(max) was approximately 5 min in all four groups. The mean T(1/2) value for EVs was similar to the GD value and lower than the HHT and AHT values. The mean (+/-SD) 5-min uptake was 0.13% (+/-0.05%) for EVs. The 5-min uptake in GD was higher than that in EVs(P<0.001) and correlated with free thyroxine (r=0.54) and with (99m)Tc-pertechnetate uptake (r=0.68). Uptake in HHT was higher than that in AHT (P=0.0003) and EVs (P=0.002). Uptake in AHT was lower than uptake in EVs (P=0.0001).

CONCLUSION

Five minutes is the optimal time interval between (99m)Tc-sestamibi injection and calculation of thyroid uptake. Five-minute uptake differentiates euthyroid individuals from GD patients. There is a high correlation between (99m)Tc-sestamibi and (99m)Tc-pertechnetate uptake in GD. The reduced (99m)Tc-sestamibi uptake in AHT patients is probably due to glandular destruction and fibrosis. Inflammatory infiltrate and high mitochondrial density in thyrocytes possibly explain the increased uptake in GD and HHT.

Leptin injection during lactation alters thyroid function in adult rats

The aim of this study was to evaluate the effects of hyperleptinemia during the first ten days of life on thyroid function in adulthood. After birth, pups were separated into two groups: L8 - receiving daily injections of recombinant mouse leptin (8 microg/100 g body weight, sc) and control (C) - receiving the same volume of saline. Both groups were treated for the first 10 days of lactation. The animals were sacrificed at 150 days of age, and the blood was collected for leptin, TSH, total triiodothyronine (TT 3 ) and total thyroxin (TT 4 ) serum concentration determinations by radioimmunoassay. The thyroid gland was excised to determine thyroid iodine uptake. Leptin, TT 3 and TT 4 serum concentrations in L8 group were significantly (108 %, 47 % and 32 %; p < 0.05) higher than that of controls. There was no significant difference between the groups related to thyroid iodine uptake and TSH serum concentration. These data suggest that the first half of lactation period is important in determining thyroid function in adulthood, and that it can be programmed by serum leptin concentration.

Brain single-photon emission computed tomography and magnetic resonance imaging in Machado-Joseph disease

BACKGROUND

Machado-Joseph disease (MJD) is one of the most frequently encountered spinocerebellar ataxias. However, few reports on brain single-photon emission computed tomographic (SPECT) imaging (BSI) with hexylmethylpropylene amineoxine labled with technetium Tc 99m and magnetic resonance imaging (MRI) have been performed for the evaluation of patients with MJD.

OBJECTIVES

To investigate possible abnormalities with BSI and MRI in patients with MJD and to correlate these findings with the duration of symptoms; cerebellar, extrapyramidal, and pyramidal syndromes; and the molecular characteristics of the MJD mutation.

PATIENTS AND METHODS

Twelve patients (8 males and 4 females [mean age, 39 years]) with genetically proven MJD were studied. The patients underwent BSI and MRI on the same day. Brain SPECT imaging was performed after an intravenous injection of 99mTc-hexylmethylpropylene amineoxine. The transaxial, coronal, and sagittal BSIs obtained were submitted to visual and semiquantitative analyses. Magnetic resonance imaging was obtained in a 2-T system with coronal, sagittal, transaxial, and 3-dimensional (volumetric) acquisitions. The volumes of the cerebellar hemispheres and vermis were calculated. Control groups for BSI (22 female and 20 male subjects [mean age, 33 years]) and MRI (13 female and 4 male subjects [mean age, 32.2 years]) were included for comparison.

RESULTS

Correlation was observed between the perfusion abnormalities identified by visual analysis in the BSI with the structural abnormalities observed on MRI in the parietal lobes and vermis. Brain SPECT imaging identified (by visual analysis) more perfusion abnormalities in the inferior portion of the frontal lobes, mesial and lateral portions of the temporal lobes, basal ganglia, and cerebellar hemispheres. Magnetic resonance imaging identified more abnormalities in the pons and superior portions of the frontal lobes. Olivary atrophy was identified by MRI. Semiquantitative analysis showed a statistically significant difference of perfusion in the inferior and superior portions of the frontal lobes, lateral portion of the temporal lobes, parietal lobes, left basal ganglia, cerebellar hemispheres, and vermis when compared with the control group. A significant difference was noted between the vermis and cerebellar volumes on MRI when compared with the control group. A significant relationship was observed between the perfusion of the left parietal lobe (P =.05) and extrapyramidal syndrome. There was a tendency toward an inverse relationship between the duration of symptoms and the perfusion of the cerebellar hemispheres (rho = -0.37; P =.24) and volume of the vermis (rho = -0.30; P =.34); between the length of the expanded (CAG)n repeat and the perfusion of the left parietal lobe (rho = -0.32; P =.36), vermis (rho = -0.28; P =.43), and pons (rho = -0.28; P =.42). A direct association was observed between the length of the expanded (CAG)n repeat and the perfusion of the lateral portion of the right temporal lobe (rho = 0.67; P =.03).

CONCLUSIONS

Brain SPECT imaging and MRI were capable of identifying subclinical abnormalities in individuals with MJD. These findings may be helpful for a better understanding of the pathophysiology of this disease.

Incidental focal thyroid uptake on FDG positron emission tomographic scans may represent a second primary tumor

PURPOSE

This article discusses the value of incidental thyroid uptake of fluorodeoxyglucose (FDG) on whole-body positron emission tomography (PET) scans performed in patients with cancer. This issue has been reported diversely in the literature.

MATERIALS AND METHODS

Whole-body PET scans of four patients with cancer (two of them women; age, 49 to 78 years) in whom focal thyroid uptake was visualized and subsequently correlated with thyroid carcinoma based on cytologic or histopathologic data were reviewed. The clinical outcomes of these patients were analyzed retrospectively. Maximum and average standardized uptake values (SUVs) of thyroid accumulation were recalculated in all patients.

RESULTS

Two of the four patients referred for FDG PET scans had lung adenocarcinomas, one had prostate carcinoma, and one had an unknown primary tumor. Focal thyroid uptake was visualized, with maximum and average SUVs ranging from 3.7 and 2.3 to 53 and 34, respectively. These findings were correlated with cytologic (two patients) or histopathologic data (two patients) that indicated thyroid carcinoma. In two patients, their treatment was changed and total thyroidectomy was performed; in one of them the SUVs of the focal thyroid accumulation (maximum and average values of 7.9 and 4.8, respectively) were less than the cutoff values for thyroid cancer noted in the literature. The clinical condition of the other two patients did not permit additional investigation or treatment for thyroid carcinoma.

CONCLUSION

Increased focal thyroid uptake on whole-body FDG PET scans should not be overlooked, even when it is not marked, and should prompt further investigation to rule out cancer.

FDG-PET standardized uptake values in normal anatomical structures using iterative reconstruction segmented attenuation correction and filtered back-projection

Filtered back-projection (FBP) is the most commonly used reconstruction method for PET images, which are usually noisy. The iterative reconstruction segmented attenuation correction (IRSAC) algorithm improves image quality without reducing image resolution. The standardized uptake value (SUV) is the most clinically utilized quantitative parameter of [fluorine-18]fluoro-2-deoxy-D-glucose (FDG) accumulation. The objective of this study was to obtain a table of SUVs for several normal anatomical structures from both routinely used FBP and IRSAC reconstructed images and to compare the data obtained with both methods. Twenty whole-body PET scans performed in consecutive patients with proven or suspected non-small cell lung cancer were retrospectively analyzed. Images were processed using both IRSAC and FBP algorithms. Nonquantitative or gaussian filters were used to smooth the transmission scan when using FBP or IRSAC algorithms, respectively. A phantom study was performed to evaluate the effect of different filters on SUV. Maximum and average SUVs (SUVmax and SUVavg) were calculated in 28 normal anatomical structures and in one pathological site. The phantom study showed that the use of a nonquantitative smoothing filter in the transmission scan results in a less accurate quantification and in a 20% underestimation of the actual measurement. Most anatomical structures were identified in all patients using the IRSAC images. On average, SUVavg and SUVmax measured on IRSAC images using a gaussian filter in the transmission scan were respectively 20% and 8% higher than the SUVs calculated from conventional FBP images. Scatterplots of the data values showed an overall strong relationship between IRSAC and FBP SUVs. Individual scatterplots of each site demonstrated a weaker relationship for lower SUVs and for SUVmax than for higher SUVs and SUVavg. A set of reference values was obtained for SUVmax and SUVavg of normal anatomical structures, calculated with both IRSAC and FBP image reconstruction algorithms. The use of IRSAC and a gaussian filter for the transmission scan seems to give more accurate SUVs than are obtained from conventional FBP images using a nonquantitative filter for the transmission scan.

Activation of the growth plates on three-phase bone scintigraphy: the explanation for the overgrowth of fractured femurs

Children with an uncomplicated femoral fracture, treated with superimposition of fragments and intentional shortening, usually develop overgrowth of the fractured femur and the ipsilateral tibia which may compensate for the initial shortening and enable the limb in question to reach a length similar to that on the normal side. The overgrowth is evaluated clinically and by scanography. The increased metabolic activity of the growth plates that support this overgrowth has not been documented by any laboratory method. In order to evaluate the metabolic activity of the growth plates, 18 patients (11 males, seven females; mean age 6.1 years) with fractures of the femur were studied at three different time intervals (2-5 months, 6-12 months and 18-24 months). Three-phase bone scintigraphy was performed in all patients. Ten children (five males, five females; mean age 7.5 years) who had had bone imaging for other reasons were used as the control group. Visual analysis of the flow and equilibrium phases was performed for the distal femoral and proximal tibial growth plates. Visual and semi-quantitative analyses of the delayed images were performed for the distal femoral and proximal and distal tibial growth plates. Semi-quantitative analyses yielded the following activity ratios: (a) the distal femoral growth plate of the fractured femur to the contralateral one (FR); (b) the proximal growth plate of the tibia on the side of the fractured femur to the contralateral one (TpR); (c) the distal growth plate of the tibia on the side of the fractured femur to the contralateral one (TdR); and (d) in the control group, the distal growth plates of both femora (FCG) and the proximal (TCGp) and distal (TCGd) growth plates of the tibiae. Visual analysis of the blood flow, equilibrium and delayed images showed increased activity in the distal femoral growth plates during the first and second time intervals, but not during the third. No significant activity changes were found in the proximal and distal tibial growth plates during any of the phases analysed. The mean and standard deviation for FR in the three time intervals were: FRI=1.22+/-0.27, FRII=1.17+/-0.16 and FRIII=1.09+/-0.20. FR values were significantly higher than in the control group (FCG=0.99+/-0.03) (P=0.033). The mean and standard deviation for TpR in the three time intervals were: TpRI=1.08+/-0.18, TpRII=0.94+/-0.09 and TpRIII=0.96+/-0.20. TpR values were not significantly different from those in the control group (TCGp=1.00+/-0.05). However, TpRI was significantly higher than TpRII (P=0.043). The mean and standard deviation for TdR in the three time intervals were: TdRI=1.10+/-0.41, TdRII=1.05+/-0.15 and TdRIII=1.13+/-0.36. TdR values were not significantly higher than in the control group (TCGd=1.00+/-0.04) (P=0.777). These results support the concept that three-phase bone imaging is able to quantify and determine that activation occurs in the distal femoral and proximal tibial growth plates of fractured femora. This phenomenon may explain the overgrowth observed in this injured bone structure.

Tc-99m MDP uptake in uterine leiomyoma

A 47-year-old woman with adenocarcinoma of the right breast had bone scintigraphy with Tc-99m MDP. Bone imaging did not show any metastases. However, a large area of increased tracer uptake was seen extending from the abdomen to the pelvis. Abdominal ultrasound revealed a large solid and heterogeneous mass, measuring 18 x 11 x 14.3 cm, that originated in an empty uterus. A biopsy of the surgical specimen showed a leiomyoma of the uterus.

Gallium-67 imaging in a patient with paracoccidioidomycosis: a case report

A 26 year-old female was admitted with abdominal pain, fever and weight loss. The clinical and laboratory investigations led to the diagnosis of paracoccidioidomycosis. Gallium-67 whole body images correlated well with the clinical course of the disease and with the patient's prognosis.

Detection of synchronous carcinomas of the colon with F-18 fluorodeoxyglucose: a case report

Colon and rectal carcinomas are common in North America and Northwestern Europe. In South America, the risk of this disease is not as great. Adenocarcinomas are the most common types of tumors, and they occur mainly in the descending colon, sigmoid, and rectum. A patient with a possible right colon carcinoma was examined using F-18 FDG.

Thyroid suppression test with L-thyroxine and [99mTc] pertechnetate

OBJECTIVE

The thyroid suppression test is still used in some centres as an adjunt in the diagnosis of autonomous functioning thyroid nodules. With the purpose of minimizing the disadvantages of the original T3 suppression test, we have evaluated the efficacy of a method using L-thyroxine as TSH suppression agent and [99 mTc] pertechnetate as radiopharmaceutical.

DESIGN

Open nonrandomized prospective study

MATERIALS AND METHODS

A control group of 15 normal volunteers (11 males, 4 females; 21-35 years, mean 26.4 years) and a patient group of 20 patients (18 females, 2 males; 27-83 years, mean 53.6 years) divided into 4 subgroups, were studied: 7 patients with autonomous functioning nontoxic nodules, 3 with autonomous functioning toxic nodules, 7 with Graves disease and 3 with nonautoimmune diffuse toxic goitre. Baseline thyroid uptake and imaging were begun 20 minutes after an intravenous injection of 370 MBq (10 mCi) of [99 mTc] pertechnetate. This was followed by a single daily intake of 2 microg/kg of L-thyroxine, for 10 days. Thyroid imaging and uptake were then repeated.

RESULTS

In the control group [99 mTc] pertechnetate uptake after L-thyroxine suppression had a mean reduction of 75.8 +/- 7.69% (58-87%) in comparison to the baseline level. All subjects were euthyroid by clinical and laboratory criteria and none complained of side-effects, despite significant suppression of TSH levels. In the patient group, thyroid uptake after suppression decreased in 10 patients (maximum reduction 39%), was unchanged in 2 patients and increased in the remaining 8 patients.

CONCLUSION

The method described was efficient for demonstration of autonomous thyroid tissue, since none of the patients showed significant reduction of thyroid uptake after L-thyroxine suppression compared with the control group. This test was as effective as the original T3 suppression test, but more convenient to the patient: no side-effects, ease of hormonal intake, low dosimetry and short stay in the nuclear medicine laboratory.

Brain SPECT imaging in Huntington's disease before and after therapy with olanzapine. Case report

Olanzapine, an atypical antipsychotic drug, was administered to a patient with Huntington's disease (HD) with marked choreiform movements. Brain SPECT with 99mTc-HMPAO was performed before and after treatment. Brain SPECT imaging has been performed in patients with HD in order to determine the status of basal ganglia perfusion. The use of brain SPECT with 99mTc-HMPAO before and after treatment in patients with HD has not been yet reported. The marked hypoperfusion of the basal ganglia on brain SPECT performed before therapy with olanzapine improved significantly after treatment.

[Actinomycotic mycetomas in Rio Grande do Sul--report of 4 cases]

São relatados quatro casos de micetoma causados por Nocardia brasiliensis, ocorridos no Rio Grande do Sul. É revista a literatura rio-grandense-do-sul.

Small forms and hyphae of paracoccidioides brasiliensis in human tissue

A 53 year-old man had a three-year recurrent respiratory infection. No fungi was detected in sputum examinations. Immunodiffusion test with paracoccidiodin revealed two precipitin bands. Very small forms and hyphae of a fungus were seen on silver methenamine stained serial sections from lung's lesion. P. brasiliensis was identified on the basis of the rare multibudding small forms.

The status of histoplasmosis in Brazil

Thirty four cases of the progressive form of histoplasmosis, five epidemics of the mycosis, many histoplasmin skin test surveys and few clinical or histological evidences of the benign form of the disease were reported in Brazil. The occurrence of the infection in animals and the isolation of H. capsulatum from soil have also been reported.

Progressive pulmonary paracoccidioidomycosis a study of 34 cases observed in Rio Grande do Sul (Brazil)

Data on 34 patients with progressive pulmonary paracoccidioi domycosis seen in the State of Rio Grande do Sul (Brazil) are reviewed. Clinical manifestations were similar to those of a prolonged or a recurrent undifferentiated respiratory infection. Roentgenographic findings were also non-characteristic. A mycologic diagnosis was readily made when sputum was available.

Chromomycosis: a clinical and mycologic study of thirty-five cases observed in the hinterland of Rio Grande do Sul, Brazil

Data on thirty-five patients with chromomycosis seen in the hinterland of the State of Rio Grande do Sul (Brazil) are reviewed. Atypical lesions were found in 28.5% of the patients. The lesions were localized on the upper limbs and face in 14.2% and 8.5% of the patients, respectively. The clinical aspects and mycologic diagnosis of chromomycosis are discussed, and an account is given of its regional distribution in Rio Grande do Sul.