Publications (180) View all
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Article: Assessment of SPM in Perfusion Brain SPECT Studies. A Numerical Simulation Study Using Bootstrap Resampling Methods
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ABSTRACT: Statistical parametric mapping (SPM) has become the technique of choice to statistically evaluate positron emission tomography (PET), functional magnetic resonance imaging (fMRI), and single photon emission computed tomography (SPECT) functional brain studies. Nevertheless, only a few methodological studies have been carried out to assess the performance of SPM in SPECT. The aim of this paper was to study the performance of SPM in detecting changes in regional cerebral blood flow (rCBF) in hypo- and hyperperfused areas in brain SPECT studies. The paper seeks to determine the relationship between the group size and the rCBF changes, and the influence of the correction for degradations. The assessment was carried out using simulated brain SPECT studies. Projections were obtained with Monte Carlo techniques, and a fan-beam collimator was considered in the simulation process. Reconstruction was performed by using the ordered subsets expectation maximization (OSEM) algorithm with and without compensation for attenuation, scattering, and spatial variant collimator response. Significance probability maps were obtained with SPM2 by using a one-tailed two-sample f-test. A bootstrap resampling approach was used to determine the sample size for SPM to detect the between-group differences. Our findings show that the correction for degradations results in a diminution of the sample size, which is more significant for small regions and low-activation factors. Differences in sample size were found between hypo- and hyperperfusion. These differences were larger for small regions and low-activation factors, and when no corrections were included in the reconstruction algorithm.IEEE Transactions on Biomedical Engineering 08/2008; · 2.28 Impact Factor -
Article: The goal is quantitative cerebral blood flow.
Journal of Neuroradiology 01/2006; 32(5):291-3. · 1.21 Impact Factor -
Article: 111Indium labelled leukocyte scintigraphy in the detection of acute prostatitis.
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ABSTRACT: Although prostatitis is a common problem the diagnosis is still controversial despite the availability of a wide variety of diagnostic tools. In fact, there is still no accurate method of localizing the infected tissue. The aims of the present study were to assess whether 111In labelled leukocytes (ILLs) accumulated in the infected tissue of acute prostatitis and if such uptake responded to treatment. We prospectively studied 10 adult male patients who had community acquired prostatitis and compared them with six male patients who had urinary tract infections but without prostatitis. An initial urinary culture and two blood cultures were carried out for each patient. All patients were followed up for 8 weeks after therapy was completed. Pre- and post-treatment scintigraphies were performed. Before treatment, all patients with prostatitis showed uptake of ILLs in the prostate area. After the patients had completed treatment with antibiotics, the scintigraphy results showed no uptake in the prostate area in 9/10 patients. The remaining patient showed a marked decrease in the uptake of ILLs. None of the six patients with urinary tract infection showed ILL uptake in the prostate region. It is suggested that ILLs could be useful for detecting acute prostatitis, especially in clinically ambiguous patients with urological infections. Furthermore, scintigraphy with 111In labelled leukocytes could help to determine the most appropriate course of therapy.Nuclear Medicine Communications 12/2002; 23(11):1137-42. · 1.40 Impact Factor -
Article: Repetitive transcranial magnetic stimulation in the treatment of chronic negative schizophrenia: a pilot study.
Journal of Neurology Neurosurgery & Psychiatry 08/1999; 67(1):129-30. · 4.76 Impact Factor -
Article: Ictal laughter associated with paroxysmal hypothalamopituitary dysfunction.
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ABSTRACT: Seizures with ictal laughter (also termed gelastic seizures) have been associated with hypothalamic hamartomas and precocious puberty. It is not known, however, where in the brain such seizures originate. We describe a child with gelastic seizures and a hypothalamic lesion (probably a hamartoma) in whom two dysfunctional phenomena were observed. First, there was a hyperperfusion in the hypothalamopituitary areas shown by ictal [99m]Tc hexamethyl-propyleneamine oxime (HM-PAO) single photon-emission computed tomography (SPECT). Second, there was an ictal pulse of gonadotropins, 17 beta-estradiol, and growth hormone well above the normal limits in one of the seizures. These findings suggest that gelastic seizures associated with hypothalamic hamartomas are generated in the hypothalamus or in its neighboring regions and that these seizures may cause paroxysmal dysfunction of the hypothalamopituitary axis.Epilepsia 02/1997; 38(1):114-7. · 3.96 Impact Factor
