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J Villanueva-Meyer

Publications and source records attributed to J Villanueva-Meyer.

At least 19 recordsLinked to original sources
PubMed2000

Diagnostic accuracy of 99mTc-sestamibi breast imaging: multicenter trial results.

UNLABELLED: Although mammography is well established as a first-line tool for breast cancer screening and detection, efforts to develop complementary procedures continue. Observation of 99mTc-sestamibi tumor uptake provided the impetus for its evaluation as an adjunctive technique. This trial's objectives were to determine in a multicenter trial the diagnostic accuracy of 99mTc-sestamibi in women with suspected breast cancer and to investigate factors influencing diagnostic accuracy. METHODS: Our multicenter trial enrolled 673 women (387 with nonpalpable abnormalities; 286 with palpable abnormalities) scheduled for excisional biopsy or mastectomy. Blinded and unblinded interpretations of scintigraphic images were compared with core laboratory established histopathologic diagnoses to define the diagnostic accuracy of 99mTc-sestamibi breast imaging. RESULTS: Blinded readers' diagnostic accuracy was 78%-81%. Inter-reader agreement was excellent, ranging from 95% to 100% (kappa = 0.82-0.99). Overall institutional sensitivity and specificity for 99mTc-sestamibi breast imaging were 75.4% and 82.7%, respectively. In this population with a 40.1% disease prevalence, the positive predictive value was 74.5% and the negative predictive value was 83.4%. The negative predictive value was 94% in patients with a 40% or lower mammographic likelihood of breast cancer. Sensitivity was higher for palpable abnormalities; specificity was higher for nonpalpable abnormalities. Sensitivity was decreased for tumors <1 cm in largest dimension but appeared not to be affected by patient's age. CONCLUSION: As an adjunct to current procedures, 99mTc-sestamibi breast imaging may contribute to patient management decisions in selected populations, including women with dense breasts, mammographically indeterminate lesions >1 cm, and palpable abnormalities.

Biopsy↗
PubMed1998

Imaging of brain tumors in AIDS patients by means of dual-isotope thallium-201 and technetium-99m sestamibi single-photon emission tomography.

Our aim was to evaluate the use of dual-isotope thallium-201 (Tl) and technetium-99m sestamibi (sestamibi) simultaneous acquisition in brain single-photon emission tomography (SPET) for the differentiation between brain lymphoma and benign central nervous system (CNS) lesions in AIDS patients. Thirty-six consecutive patients with enhancing mass lesions on magnetic resonance (MR) imaging were included in the study. SPET of the brain was performed to obtain simultaneous Tl and sestamibi images. Regions-of-interest were drawn around the lesion and on the contralateral side to calculate uptake ratios. The final diagnosis was reached by pathologic findings in 17 patients and clinical and/or MR follow-up in 19 patients. Of the 36 patients, 11 had brain lymphoma, 1 glioblastoma multiforme, 15 toxoplasmosis and 9 other benign CNS lesions. Correlation between SPET and the final diagnosis revealed in 10 true-positive, 23 true-negative, 1 false-positive and 2 false-negative studies. All patients with toxoplasmosis had negative scans. A patient with a purulent infection had positive scans. Tl and sestamibi scans were concordant in every lesion. The same lesions that took up Tl were also visualized with sestamibi. However, sestamibi scans showed higher lesion-to-normal tissue uptake ratios (3.7 +/- 1.8) compared with those of Tl (2.3 +/- 0.8, P < 0.002). Simultaneous acquisition of Tl and sestamibi can help differentiate CNS lymphoma from benign brain lesions in AIDS patients.

Acquired Immunodeficiency Syndrome↗
PubMed1998

MR and TL-210 spect imaging with pathologic correlation for the assessment of CNS lymphoma vs. toxoplasmosis in AIDS patients.

PURPOSE: Analyze the value of TL-201 (Tl) brain single-photon emission computed tomography (SPECT), to differentiate CNS lymphoma from toxoplasmosis in AIDS patients. MATERIAL AND METHODS: Twenty-four AIDS patients with MR enhancing lesion(s), underwent a brain Tl SPECT. Final diagnosis was established by pathology and clinical/MR follow-up. RESULTS: Nine patients had CNS tumor, 9 toxoplasmosis and 6 other non-tumorous lesions. The sensitivity of T1 to diagnose CNS tumor was 77% and the specificity 93%. Two false negative studies correspond to tumors with significant necrosis. CONCLUSIONS: T1 proved useful for differentiating brain neoplasm from toxoplasmosis. Tumors with significant necrosis, did not show the expected increase in T1 uptake. Determination of T1 uptake ratios help detect tumor with faint tracer uptake.

AIDS-Related Opportunistic Infections↗
PubMed1997

Correlations between SPECT regional cerebral blood flow and psychometric testing in patients with Alzheimer's disease.

Thirty-nine patients with probable Alzheimer's disease (AD) were studied with [99mTc]HMPAO SPECT and a standardized neuropsychological battery testing intellect, memory, attention, language, motor and praxis functions, and depression. Spearman rank correlations and multivariate regression analyses were performed to correlate quantitative regional perfusion deficits to these tests. Patients were found to have decreased perfusion of left frontal, parietal, and temporal regions relative to right. WAB repetition scores and bilateral temporal flow were significantly correlated (P < 0.01). Correlations between visual memory and bilateral temporal flow and those between Mini-Mental State/ Geriatric Depression Scale scores and bihemispheric flow approached significance. Although in this study regional cerebral blood flow was relatively insensitive to neuroanatomical abnormalities underlying specific cognitive deficits, it may have some specificity for identifying the language disorder in AD.

Aged↗
PubMed1997

Temporal lobe perfusion asymmetries in schizophrenia.

UNLABELLED: Structural and functional neuroimaging techniques have consistently demonstrated that abnormal lateralization of temporal lobes may be important in identifying the pathophysiologic processes in schizophrenia. The exact nature of these reported abnormalities has not been consistent. METHODS: We examined temporal lobe perfusion using HMPAO-SPECT in 22 individuals with schizophrenia in an effort to establish whether temporal lobe perfusion asymmetry is seen in these individuals, as compared to a group of 22 age- and sex-matched controls. RESULTS: We found that the asymmetry index, a measure of perfusion differences between two homologous compared areas, was lower (more negative) in schizophrenic individuals. The asymmetry indices of patients considered with the results from globally corrected ROI means indicated that the left temporal lobes of individuals with schizophrenia were significantly hypoperfused when compared to controls. This finding does not appear to be caused by medication effects, demographic variables, handedness, imaging artifacts or analysis techniques. CONCLUSION: In our sample, patients with schizophrenia appear to have significant left hypoperfusion relative to right of their temporal lobes. Abnormal lateralization of temporal lobe blood flow may have important clinical implications by assisting with diagnosis and appropriate treatment for individuals with schizophrenia.

Adolescent↗
PubMed1996

Intense myocardial and lung uptake of 99m-Tc-pyrophosphate using single photon emission computed tomography in a patient with end-stage renal disease and secondary hyperparathyroidism.

Metastatic calcification, a frequent and potential lethal complication of chronic renal failure, is rarely detected before death because of the absence of specific radiographic abnormalities. We report the case of a patient on haemodialysis, with secondary hyperparathyroidism and a second degree A-V block who had a 99m-Tc-pyrophosphate scan to rule out myocardial infarction. The scintigram showed marked myocardial and lung uptake that is indicative of severe metastatic hydroxyapatite calcifications.

Adult↗
PubMed1996

Mammoscintigraphy with technetium-99m-sestamibi in suspected breast cancer.

UNLABELLED: Our goal was to determine the clinical usefulness of 99mTc-sestamibi to identify breast cancer in patients prior to biopsy. METHODS: We studied 66 patients who received 20 mCi 99mTc-sestamibi intravenously. Lateral and anterior planar images were gathered within 30 min of the injection. Only focal increased uptake was interpreted as positive. Confirmatory pathologic diagnoses were obtained within 2 mo. The prevalence of breast cancer in our sample was 54%. RESULTS: We report an overall sensitivity of 83% and specificity of 93% for the diagnosis of breast cancer. In palpable lesions, the sensitivity was of 94% with a specificity of 91%, while in nonpalpable abnormalities the sensitivity was of 64% with a 100% specificity. Six patients with a malignancy had negative scans, four of these lesions were nonpalpable. Only two of 31 patients with benign lesions had an abnormal scan. CONCLUSION: Mammoscintigraphy with 99mTc-sestamibi has high specificity and adequate sensitivity for the noninvasive diagnosis of breast carcinomas.

Adult↗
PubMed1996

Pediatric gastric emptying: value of right lateral and upright positioning.

UNLABELLED: Gastroesophageal reflux and gastric emptying are usually assessed simultaneously with a 1-hr procedure. After ingestion of radiolabeled formula sequential images are gathered when the infant is in the supine position. This position is adequate for gastroesophageal reflux assessment, but delays gastric emptying. METHODS: We studied 48 children, 1 wk to 2 yr of age, who presented with vomiting or failure to thrive. They received 99mTc-sulphur colloid in formula. After completing 1 hr supine imaging we obtained additional abdominal views after changing the position of the infant to right lateral for 30 min, and upright for another 30 min. RESULTS: The percent of gastric emptying at 60 min in the supine position was 35% +/- 19%. After 90 min, in the right lateral decubitus, the percent gastric emptying was 60% +/- 25%. At 120 min, after an upright period, the gastric emptying was 73% +/- 20%. In the supine position 19 of 48 patients showed significant emptying (defined as > 40% emptying). This increased to 41 of 48 normal studies considering the right lateral position and to 45 of 48 normal studies considering the infant upright position. CONCLUSION: Many patients with delayed gastric emptying show significant emptying just by changing position. We routinely complement gastric emptying studies with delayed views in the right lateral and upright position.

Child, Preschool↗
PubMed1995

Regional 133xenon cerebral blood flow and cerebral 99mTc-HMPAO uptake in patients with obsessive-compulsive disorder before and during treatment.

We previously reported increased regional cerebral cortical uptake and decreased caudate nucleus uptake of 99mTc-HMPAO in patients with obsessive-compulsive disorder(OCD) before treatment compared to matched normal controls. In the present study, we determined whether or not these changes persisted during treatment. Single-photon emission computed tomography was used to measure regional cerebral blood flow (rCBF) by 133Xe inhalation and cerebral uptake of 99mTc-HMPAO in eight adult male OCD patients before and during treatment with chlomipramine, and in eight age-matched normal male controls. With 133Xe, there were no significant differences in rCBF between patients with OCD and their matched controls, and no significant differences in rCBF in the patients before and during treatment. Significantly increased HMPAO uptake in the orbital frontal cortex, posterofrontal cortex, and high dorsal parietal cortex bilaterally occurred in the OCD patients before treatment compared to their matched controls, and there were significant reductions of HMPAO uptake, into the normal range, in all these areas in the patients during treatment. Significantly reduced HMPAO uptake in the caudate nucleus bilaterally occurred in the patients before treatment compared to their matched controls, and these reductions persisted during treatment. This study provides additional support for the involvement of both the orbital frontal cortex and the caudate nuclei in the pathophysiology of OCD.

Adult↗
PubMed1995

Three-phase bone and Ga-67 scintigraphy in disseminated sporotrichosis.

A 27-year-old man, who had been shoveling gravel in southern Texas for 3 years, had a history of papules and nodules in the left lateral wall of the abdomen. The lesions increased in number and severity with spread to other regions of the body. A punch biopsy of the right arm lesion revealed intracellular, round and cigar shaped budding yeast. The cultures grew Sporotrichum schenkii. Three-phase bone imaging and a Ga-67 scan defined the extent of the disease including involvement of the right tibia, left second metacarpal, and the left wrist joints, the latter two of which were not apparent on clinical examination.

Adult↗
PubMed1994

Tc-99m sestamibi imaging of a pancreatic VIPoma and parathyroid adenoma in a patient with multiple type I endocrine neoplasia.

Technetium-99m sestamibi is known to localize in primary malignant and metastatic tumors. Specifically, brain, breast, thyroid, parathyroid, lung, and kidney tumors have been imaged. The Verner Morrison syndrome, which is caused by excessive vasoactive intestinal peptide (VIP), consists of watery diarrhea, hypokalemia, and achlorhydria. This condition is rarely associated with multiple endocrine neoplasia. The authors present a case of multiple endocrine neoplasia type I with visualization of a pancreatic VIPoma and parathyroid adenoma with Tc-99m MIBI.

Adenoma↗
PubMed1994

Cerebral blood flow changes with acute cocaine intoxication: clinical correlations with SPECT, CT, and MRI.

In summary, these data suggest that widespread primary or secondary cerebral vasoconstriction is common in patients with neurological complications from cocaine. In most patients, SPECT showed wide-spread hypoperfusion in regions that had no clear clinical significance (e.g., the periventricular area). In many, the SPECT was performed more than 24 hours after the onset of neurological symptomatology. These findings raise several questions. It has been assumed that these SPECT changes in patients with acute neurological symptoms are temporary, although it will be important to determine whether these areas of hypoperfusion persist after symptoms have abated. Recently, Holman and colleagues (1991) found multifocal and deep areas of hypoperfusion with SPECT in 16 of 18 patients with a history of chronic cocaine abuse. Although most of the subjects tested positive for cocaine, several had abstained from cocaine use for weeks prior to the study. All 18 subjects had neuropsychological deficits, 13 mild and 5 moderate. Similarly, Pascual-Leone and colleagues (1991) have shown that CT scan atrophy strongly correlates with the duration of cocaine abuse, suggesting that brain injury may occur with continued use of cocaine. It is the authors' concern that cocaine abuse might produce permanent changes in cerebral perfusion. In conclusion, brain SPECT was found to be a useful procedure in the evaluation of acute cocaine intoxication. Brain SPECT revealed focal cortical lesions not seen on head CT or MRI, which corresponded to clinical deficits. In addition, [99mTc]HMPAO brain SPECT had a characteristic scalloped appearance, and this may be a marker for acute intoxication with cocaine. This study further supports the contention that cocaine causes neurological disease by its vasoconstrictive action.

Adult↗
PubMed1993

Cerebral abnormalities in myotonic dystrophy. Cerebral blood flow, magnetic resonance imaging, and neuropsychological tests.

OBJECTIVE: To study cerebral abnormalities in myotonic dystrophy (MD) and determine the different patterns of cerebral function in patients with MD with maternal (mMD) vs paternal (pMD) inheritance. DESIGN: Patients with MD and normal controls were studied with neuropsychological testing, magnetic resonance imaging, and single photon emission computed tomography. SETTING: Studies were done at Harbor-UCLA Medical Center, Torrance, Calif. PATIENTS AND OTHER PARTICIPANTS: Twenty-two consecutive-patients with MD, 11 of whom had pMD and eight mMD, and 10 normal controls were studied. Diagnoses were made on the basis of family history, electromyography, and clinical examinations. Normal subjects in the same age distribution were studied for comparisons. RESULTS: We found significantly lower neuropsychological performance and cerebral blood flow in the patients with MD compared with the controls. Patients with mMD had statistically lower scores on IQ tests and more extensive cerebral hypoperfusion when compared with those with pMD. Changes in cerebral blood flow were most severe in the frontal and temporoparietal association cortex. Cerebral blood blow measures strongly correlated with IQ. CONCLUSIONS: Patients with mMD had earlier onset of disease and lower IQs than the pMD group. The pattern of cerebral perfusion in the mMD group was consistent with a diffuse brain injury, while cerebral perfusion in pMD showed more minor changes. These findings emphasize the cognitive differences between mMD and pMD.

Adolescent↗
PubMed1993

Cerebral perfusion and neuropsychological consequences of chronic cocaine use.

Research indicates that cocaine significantly constricts the cerebral vasculature and can lead to ischemic brain infarction. Long-term effects of intermittent or casual cocaine use in patients without symptoms of stroke or transient ischemic attack were investigated. Single-photon emission computed tomography with xenon-133 and [99mTc]hexamethylpropyleneamine oxime, magnetic resonance imaging, and selected neuropsychological measures were used to study cerebral perfusion, brain morphology, and cognitive functioning. Patients were drug free for at least 6 months before evaluation. All showed regions of significant cerebral hypoperfusion in the frontal, periventricular, and/or temporal-parietal areas. Deficits in attention, concentration, new learning, visual and verbal memory, word production, and visuomotor integration were observed. This study indicates that long-term cocaine use may produce sustained brain perfusion deficits and persistent neuropsychological compromise in some subgroups of cocaine-abusing patients.

Adult↗