Biomedical subjects

Edwaldo E Camargo

Publications and source records attributed to Edwaldo E Camargo.

9 recordsLinked to original sources

PubMed2006

Normal values of [99mTc]pertechnetate uptake and excretion fraction by major salivary glands.

The assessment of the functional status of the salivary glands has been used in the scintigraphic evaluation of xerostomia. Several quantitative methods derived from standard dynamic scintigraphy have been suggested. However, the indices proposed are quite variable and unlikely to be useful in clinical practice. The objectives of this study were to obtain reference values of major salivary glands uptake and excretion fraction in healthy subjects and to obtain normal ratios of Tc-pertechnetate uptake by the major salivary glands in comparison to the thyroid gland uptake. The standardization of these values has the purpose of making this evaluation faster and more objective. Fifty volunteers without clinical evidence of xerostomia or thyroid disease underwent static salivary glands scintigraphy with Tc-pertechnetate. Static images were obtained at 20 minutes and then at 3 minutes after oral stimulation with lemon juice. Percent uptake, excretion fraction and salivary gland to thyroid ratio rates were calculated for the parotid and the submandibular glands. The mean of the uptake values at 20 minutes for the right and left parotid glands were respectively 0.31% and 0.26%, and for the submandibular glands 0.15%. The excretion fraction of the tracer after the lemon juice stimulation was 70% for the parotids glands, 50% for the right and 49% for the left submandibular glands. The mean+/-SD salivary gland to thyroid count ratio was 0.79+/-0.45 for the right parotid, 0.78+/-0.5 for the left parotid, 0.67+/-0.33 and 0.66+/-0.34 for the right and left submandibular glands, respectively. Salivary glands scintigraphy with uptake and excretion fraction calculation is an easy to perform, non-invasive and objective method to investigate salivary glands function. These findings help the nuclear physician to interpret salivary gland scintigraphy more objectively, even in patients with thyroid gland dysfunction in whom Tc-pertechnetate thyroid uptake may be abnormal.

Adult↗

PubMed2006

51Cr-EDTA measurements of the glomerular filtration rate in patients with sickle cell anaemia and minor renal damage.

BACKGROUND: Creatinine clearance has been reported to be inaccurate for the estimation of glomerular filtration rate (GFR) in patients with sickle cell anaemia (SCA). Inulin clearance, the reference method for GFR estimation, is impractical for routine use in these patients, and 51Cr-EDTA measurements of the GFR have been rarely reported in this disease. METHODS: In order to obtain reference 51Cr-EDTA values in this disease, we studied 70 patients (40 females; 13-59 years of age, mean: 31.6 years) with homozygous SCA, normal serum creatinine and urinary albumin excretion < or =200 microg x min(-1). All patients were submitted to single-injection 51Cr-EDTA GFR, urinary albumin and haematocrit measurements. 51Cr-EDTA clearances were calculated in different age groups (<20, 20-29, 30-39, 40-49 and >50 years). RESULTS: The mean GFR (+/-standard deviation) obtained for the 70 patients was 111.5+/-23.1 ml x min(-1). Analysis of variance for evaluation of the possible interaction effect between 51Cr-EDTA clearance and sex, age, urinary albumin and haematocrit demonstrated patient age as the only factor influencing 51Cr-EDTA clearance (P < 0.001). The Spearman correlation coefficient showed a significant relationship between 51Cr-EDTA clearance and patient age (r = -0.44, P = 0.0001), but not between 51Cr-EDTA and urinary albumin (r = -0.17, P = 0.1546) or haematocrit (r = 0.079, P = 0.5121). The group aged 20-29 years presented the highest 51Cr-EDTA clearance mean value (126.7+/-20.4 ml x min(-1)), with a progressive reduction in the older groups. CONCLUSION: Young adults with homozygous SCA, normal serum creatinine and micro-albuminuria or normo-albuminuria present supranormal 51Cr-EDTA GFR values. These values rapidly decrease after 30 years of age. We did not find association between urinary albumin and GFR in these patients.

Adolescent↗

PubMed2005

High pre-therapy [99mTc]pertechnetate thyroid uptake, thyroid size and thyrostatic drugs: predictive factors of failure in [131I]iodide therapy in Graves' disease.

BACKGROUND AND OBJECTIVE: Several factors may interfere with the success rate of radioiodine therapy (RIT) in Graves' disease. Our aim was to evaluate, retrospectively, some of these factors in the outcome of RIT. METHODS: Patient gender, age at diagnosis, ophthalmopathy, disease duration, thyroid size, drug used as clinical treatment, thionamide withdrawal period during RIT preparation, FT4, TSH and [99mTc]pertechnetate thyroid uptake prior to RIT were studied as potential interference factors for RIT success. Eighty-two Graves' disease patients were submitted to RIT after thionamide treatment failure. Prior to RIT, 67 patients were receiving methimazole and 15 propylthiouracil. Thirty-three patients received thionamides during RIT; in 49 patients the medication was withdrawn for 2-30 days. [99mTc]pertechnetate thyroid uptake was determined before RIT. Fixed doses of 370 MBq of [131I]iodide were administered to all patients. RESULTS: Eleven patients became euthyroid; 40 became hypothyroid and 31 remained hyperthyroid. There was no association between outcome and age at diagnosis, gender, ophthalmopathy, pre-RIT FT4, TSH, antithyroid antibodies or thyrostatic drug. Multiple logistic regression showed higher probability of treatment success in patients with thyroid mass <53 g (odds ratio (OR)=8.9), with pre-RIT thyroid uptake <12.5% (OR=4.1) and in patients who withdrew thionamide before RIT (OR=4.9). CONCLUSIONS: Fixed doses of 370 MBq of radioiodine seem to be practical and effective for treating Graves' disease patients with [99mTc]pertechnetate uptake <12.5% and thyroid mass <53 g. This treatment is clearly not recommended for patients with large goitre. In contrast to what could be expected, patients with a high pre-RIT thyroid uptake presented a higher rate of RIT failure.

Adolescent↗

PubMed2003

Elevated thalamic and prefrontal regional cerebral blood flow in obsessive-compulsive disorder: a SPECT study.

Functional neuroimaging studies have pointed to a possible role of cerebral circuits involving the prefrontal and anterior cingulate cortices, the striatum, and thalamus in the pathophysiology of obsessive-compulsive disorder (OCD). Regional cerebral blood flow (rCBF) of 16 drug-free Brazilian patients with OCD and 17 healthy subjects matched for age, gender, handedness and level of education was measured with [99m-Tc] HMPAO single photon emission computed tomography. Analysis of covariance identified four regions of interest with significantly higher rCBF: the right superior and inferior frontal cortex and the right and left thalamus. Positive correlations between symptom severity measured by Clinical Global Impression scores and rCBF were found in the right and left inferior frontal lobes and in the right basal ganglia. Compulsive behavior was inversely correlated with rCBF in the right thalamus, and duration of illness correlated positively with rCBF in the right and left superior frontal lobes and with the right thalamus. The findings of this SPECT study conducted in Brazil are in agreement with prior studies and provide additional support for the involvement of prefrontal-subcortical circuits in the pathophysiology of OCD. Furthermore, the study suggests that similar brain mechanisms appear to be involved cross-culturally.

Adolescent↗

PubMed2003

Neuropsychological performance and regional cerebral blood flow in obsessive-compulsive disorder.

Convergent findings from neuropsychological and neuroimaging studies have suggested that neural dysfunction in frontal-subcortical circuits may play a central role in the pathophysiology of obsessive-compulsive disorder (OCD). To further examine the relationship between these two sets of findings we investigated both neuropsychological functions and regional cerebral blood flow (rCBF) in a combined study. Fourteen unmedicated patients fulfilling DSM-IV criteria for OCD and 14 healthy controls matched for age, gender, handedness, and education were assessed on neuropsychological tests that included Trail Making Test (TMT), Rey Complex Figure Test (RCF) (copy and 5-min recall), Verbal Fluency Test (VFT), and Wisconsin Card Sorting Test (WCST). rCBF was studied with 99 mTc-hexamethyl-propyleneamine-oxime (HMPAO) single photon emission computed tomography (SPECT). Patients performed more poorly than controls (P<.05) on RCF (copy), VFT, and WCST (perseverative errors). Spearman's correlations indicated that severity of OCD correlated inversely with performance on the RCF (copy and recall scores) and positively with rCBF in the right thalamus. Positive correlations were observed between nonperseverative errors (WCST) and rCBF in frontal areas and anterior cingulate. Perseverative errors (WCST) correlated negatively with rCBF in the right thalamus. These findings are consistent with most previously published studies and suggest neural dysfunctions in the frontal-subcortical circuits probably more pronounced in the right hemisphere. They also extend the existing research, showing associations between deficits in cortical-subcortical circuitry and performance on neuropsychological tests of controlled attention and visuospatial functions.

Adolescent↗

PubMed2002

Scintigraphic follow-up of the effects of therapy with hydroxyurea on splenic function in patients with sickle cell disease.

Patients with sickle cell disease (SCD) may develop functional asplenia as a chronic complication, secondary to repeated episodes of polymerisation of haemoglobin S. It is known that increased plasma concentrations of fetal haemoglobin (HbF) reduce the polymerisation of haemoglobin S. Hydroxyurea is a chemotherapeutic agent capable of increasing HbF levels in the red blood cells and its use has recently been proposed in the treatment of SCD. The objective of this study was to evaluate the effects of long-term therapy with hydroxyurea on recovery of splenic function. Twenty-one patients (aged 3-22 years; 14 with SS haemoglobinopathy, 7 with Sbeta(0) haemoglobinopathy) were studied with liver/spleen scintigraphy before and after 6 and 12 months of treatment. All studies were submitted to visual inspection and semi-quantitative analyses using spleen/liver ratios. Imaging prior to treatment demonstrated functional asplenia in nine SS patients and one Sbeta(0) patient and impaired splenic function in five SS patients and six Sbeta(0) patients. After treatment, splenic function improved in ten patients, remained unchanged in eight and worsened in three. Using liver/spleen imaging, it was possible to demonstrate that hydroxyurea is capable of improving splenic function in some SCD patients. Improvement is not always possible and frequently does not lead to a normal splenic function even after 1 year of treatment.

Adolescent↗

PubMed2002

Bone scintigraphy as an adjunct for the diagnosis of oral diseases.

Bone scintigraphy is a very sensitive method for the detection of osteoblastic activity of the skeleton. The technique consists of imaging the uptake of bone-seeking radiopharmaceuticals, particularly technetium-99m labeled diphosphonates, in the mineral component of bone, which consists of hydroxyapatite crystals and calcium phosphate, as well as in the organic matrix such as collagen fibers. Plain radiographs, computed tomography, and magnetic resonance imaging are classified as structural imaging modalities, whereas bone scintigraphy is a functional method. In many cases, radionuclide imaging techniques are the only means by which early physiologic changes that are a direct result of biochemical alteration may be assessed, before significant bone mineral changes can be detected by other means. Since many oral diseases may cause metabolic changes in the oromaxillofacial complex, it would be of great value to use bone scintigraphy to evaluate more completely some conditions involving the bones in the region to formulate more appropriate treatment plans. Based upon the current literature, the authors discuss the possible applications of bone scintigraphy as a diagnostic and treatment planning adjunct for oral diseases. Bone scintigraphy has proven particularly useful in the study of malignant lesions and in the evaluation of vascularized bone grafts used for maxillofacial reconstructions.

Bone Diseases, Infectious↗

PubMedDate not supplied

Radioguided surgery using intravenous 99mTc sestamibi associated with breast magnetic resonance imaging for guidance of breast cancer resection.

The purpose of this study was to evaluate the feasibility of surgery radioguided with intravenous (99m)Tc sestamibi associated with magnetic resonance imaging (MRI) of the breast to detect tumor extent and guide complete tumor resection. A descriptive experimental study was developed with 10 breast cancer patients (stage IIA-IIB) who underwent mastectomy. From 2 to 10 days before surgery, the patients underwent breast MRI with 0.1 mmol/kg of gadolinium and scintimammography with a 740 MBq of (99m)Tc sestamibi. A region of interest was drawn around the tumor image and an uptake curve as a function of time was plotted to calculate the optimal time to perform radioguided surgery. In the perioperative period, the same dose of (99m)Tc sestamibi was intravenously injected into the patients. Tumor resection was performed under the guidance of a gamma probe. MRI was used to evaluate the skin and deep fascia involvement and to detect occult tumor foci which were also excised. Subsequently a modified radical mastectomy was performed. Tumor and residual breast were histopathologically examined. In a series of 10 women, all demonstrated (99m)Tc sestamibi uptake in tumor cells. Eight patients showed no disease in the residual breast, one presented with one foci of invasive ductal carcinoma measuring 0.5 cm in diameter located 5 cm from the tumor bed, and one presented with one foci of ductal carcinoma in situ measuring 0.8 cm at the resection margin. The mean tumor size in the histopathologic assessment was 3.3 cm and in MRI was 5.0 cm. Radioguided surgery using (99m)Tc sestamibi associated with MRI is a feasible technique that can be employed in tumor resection.

Adult↗

PubMedDate not supplied

The accuracy of (99m)Tc-DTPA scintigraphy in the evaluation of acute renal graft complications.

PURPOSE: Renal scintigraphy has been used for many years in the evaluation of renal transplants and can help in the diagnosis of graft complications, leading to prompt clinical management and preventing further deterioration of renal function. The purpose of this study was to evaluate the overall accuracy of renal scintigraphy with (99m)Tc-DTPA in the diagnosis of acute renal graft complications. MATERIALS AND METHODS: Seventy-six scintigraphic studies performed in 55 patients (ages ranging from 6 to 65 years), were reviewed. Scintigraphy results were compared to biopsies performed within 5 days of imaging. (99m)Tc-DTPA study was performed within a mean time of 19 days after kidney transplants. Dynamic images were performed in the anterior position of the abdomen and pelvis every 2 seconds for 80 seconds (flow phase) and every 15 seconds for 30 minutes (functional phase), after an intravenous injection of 370 MBq (10 mCi) of (99m)Tc-DTPA. RESULTS: The scintigraphic results were concordant with the biopsies in 86% of the cases studied. The sensitivities of renal scintigraphy for detection of acute tubular necrosis (ATN), acute rejection (AR) and cortical necrosis (CN) were 98%, 87% and 100%, respectively. Specificities and accuracies for detection of ATN, AR and CN were 89%, 86% and 100%, and 95%, 87% and 100%, respectively. CONCLUSION: Renal scintigraphy with (99m)Tc-DTPA showed a good overall accuracy in the detection of acute renal graft complications. It can be used as a reliable tool in the routine evaluation of these patients.

Journal Article↗