title: Evaluation of normality and reproducibility parameters of scintigraphy with (99m)Tc-MAA in the diagnosis of intrapulmonary vascular dilatations.
abstract: BACKGROUND
  The formation of intrapulmonary vascular dilations (IPVD) is the key event for the onset of hepatopulmonary syndrome, vascular changes secondary to portal hypertension that leads to hypoxemia. The diagnosis of IPVD can be made by contrasted transthoracic echocardiography or scintigraphy with technetium-macroaggregated albumin-((99m)Tc-MAA)-that is a sensitive and specific diagnostic method and quantifies the IPVD magnitude. However, its procedure and diagnostic indices are not yet standardized and well defined in health services. The aims of this study were to define normality values and evaluate the inter- and intra-observer reproducibility degree of diagnostic indexes of IPVD through (99m)Tc-MAA scintigraphy.
  
  
  METHODS
  Cross-sectional study was conducted at the Clinical Hospital, Federal University of Pernambuco (HC-UFPE) between July and December 2012. Fifteen patients with hepatosplenic schistosomiasis and nine patients without liver or heart disease (control group) were assessed. After clinical assessment, ultrasound and echocardiography, patients underwent (99m)Tc-MAA scintigraphy, and a relative brain uptake value exceeding 6 % or systemic uptake value exceeding 11 % was considered diagnostic of IPVD. Each assessment was performed by two independent observers. To analyze the results of the normal group, the nonparametric Bootsptrap method simulation model combined with the Monte Carlo method was used and to analyze inter- and intra-observer reproducibility indexes, the kappa and intra-class correlation coefficient were used.
  
  
  RESULTS
  In normal subjects, the average brain uptake of (99m)Tc-MAA was 7.9 ± 0.01 % and systemic uptake was 12.4 ± 0.03 %, with low dispersal rates for both measures. The intra-observer agreement was 100 %, with kappa index of 1.0 (p < 0.0001), suggesting a perfect agreement. The inter-observer agreement was also 100 % (kappa = 1.0, p < 0.0001) for brain uptake; however, systemic uptake showed kappa = 0.25 (p = 0.07), which features tolerable concordance. The intra-class correlation was excellent for both uptake indexes.
  
  
  CONCLUSIONS
  The normality values were slightly higher than those reported in studies from other countries. The demographic characteristics of the Brazilian population, the small number of patients or different methodologies can be the causes of such differences. (99m)Tc-MAA scintigraphy showed excellent reproducibility.
authors.affiliation: Universidade Federal de Pernambuco, Av. Prof. Moraes Rego s/n, Cidade Universitária, Recife-PE, Recife, Pernambuco, CEP 50670-901, Brazil, andrasq@hotmail.com.
authors.forename: Andréa Simone Siqueira
authors.initials: AS
authors.lastname: de Queirós
authors.forename: Simone Cristina Soares
authors.initials: SC
authors.lastname: Brandão
authors.forename: Liana Gonçalves
authors.initials: LG
authors.lastname: Macedo
authors.forename: Maira Souto
authors.initials: MS
authors.lastname: Ourem
authors.forename: Vitor Gomes
authors.initials: VG
authors.lastname: Mota
authors.forename: Luiz Arthur Calheiros
authors.initials: LA
authors.lastname: Leite
authors.forename: Edmundo Pessoa Almeida
authors.initials: EP
authors.lastname: Lopes
authors.forename: Ana Lúcia Coutinho
authors.initials: AL
authors.lastname: Domingues
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging*; D003198:Computer Simulation; D003430:Cross-Sectional Studies; D004452:Echocardiography; D058625:End Stage Liver Disease / Q000503:physiopathology; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D008171:Lung Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging*; D009010:Monte Carlo Method; D055420:Perfusion Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D013668:Technetium Tc 99m Aggregated Albumin; D014652:Vascular Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging*
chemical_list: D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin