Brain uptake of iomazenil in cirrhotic patients: a single photon emission tomography study

Abstract

Brain uptake of 123I-iomazenil was studied in seven cirrhotic patients and eight normal controls using single photon emission computerized tomography. The highest concentration of the ligand was found in the occipital cortex, which corresponds to the brain region with the highest concentration of benzodiazepine receptors. The peak uptake was delayed in patients across all brain regions. The uptake in occipital cortex was higher in low albumin cirrhotics. Patients with low albumin also presented a more delayed peak uptake in occipital cortex and a higher volume of distribution of iomazenil in plasma, compared to patients with normal albumin levels and controls. The changes in brain uptake (delayed peak uptake and increased maximal uptake in occipital cortex) appears to reflect changes in the pharmacokinetics of the ligand, particularly in cirrhotics with low levels of plasma albumin. The curve of brain uptake of the tracer was modelled into a two compartments equation, which seems to provide a practical and reliable method to calculate the slopes of acquisition and decay, time to peak and maximal acquisition.

Psychiatric neuroimaging research in Brazil: historical overview, current challenges, and future opportunities

“…17 A concise history of psychiatric neuroimaging research in Brazil and its impact During the late 1980s and 1990s, a number of Brazilian psychiatrists working abroad led the development of several quantitative, controlled psychiatric neuroimaging investigations using computed tomography, 18,19 structural MRI, 20 rCBF SPECT, 21,22 task-related fMRI, 23 and molecular imaging with SPECT. 24,25 In regard to controlled studies carried out entirely in Brazil involving samples affected by psychiatric disorders, the first quantitative neuroimaging publications in international peer-reviewed journals date from the early 2000s (Figure 1). [26][27][28][29] These papers reported the findings of studies carried out at the Laboratory of Psychiatric Neuroimaging housed in the Clinics Hospital, University of Sã o Paulo Medical School (HCFMUSP), set up in 1997.…”