title: Utility of left lateral supine position for myocardial perfusion single-photon emission computed tomography compared with other methods of correcting inferior wall attenuation.
abstract: BACKGROUND
  Single-photon emission computed tomography (SPECT) myocardial perfusion imaging is an accepted method for reflecting the pathophysiological significance of lesions detected by coronary angiography. However, it has an inherent drawback in terms of false-positive perfusion defects for the inferior myocardial wall. To overcome this problem, different acquisition techniques have been proposed, including the computed tomographic-based attenuation correction method. In this respect, a new imaging technique, left supine lateral position SPECT myocardial perfusion imaging with technetium-99m methoxyisobutylisonitrile (Tc-99m MIBI), has been proposed to eliminate this problem and its value has been investigated in this report.
  
  
  METHODS
  Sixty-two patients were prospectively and randomly enrolled in this study. They underwent Tc-99m MIBI SPECT in the supine, prone, left lateral, and sitting positions after an adequate stress test on the same day.The presence and extent of defects on stress images were noted in the supine image data set for the 11 myocardial segments, which were then labeled as 1 or 0 if a defect was present or absent, respectively. This evaluation sequence was repeated in all other image data sets. When defects persisted in other scan positions it was regarded as true positive, and when they were resolved they were regarded as false positive. By this means, the percentages of resolving perfusion defects by that imaging position were calculated for each observer per positional pair under comparison.
  
  
  RESULTS
  From six interpretations carried out by the nuclear medicine physicians, 6×11×3=198 four-fold tables in 11 segments were analyzed for discrepancies between position pairs. In 31 of 33 discrepant interpretations, defects observed in any of the other positions were resolved in the lateral position. Only in two evaluations of one observer were the discrepancies against lateral positioning for the anterior wall. If the inferior wall was considered alone, it was clearly obvious that lateral positioning was more accurate than the other positions.Intraobserver evaluation showed the methodology to be highly reproducible.The SPECT findings were concordant with coronary angiography results in selected patients.
  
  
  CONCLUSIONS
  Visual and quantitative evaluations of the variation in inferior wall activity lead us to suggest that SPECT imaging with Tc-99m MIBI be performed in the left lateral position to allow better visualization of the inferior and septal walls in those departments not able to utilize computed tomographic attenuation correction.
authors.affiliation: Departments of aNuclear Medicine bBiostatistics, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey cImperial College Healthcare NHS Trust, Service of Nuclear Medicine London, London, UK dDepartment of Biomorphological and Functional Sciences, University Federico II, Napoli, Italy eUniversity Hospital Marqués de Valdecilla, Nuclear Medicine Service, Santander, Madrid, Spain.
authors.forename: Haluk B
authors.initials: HB
authors.lastname: Sayman
authors.forename: Bedii
authors.initials: B
authors.lastname: Kanmaz
authors.forename: Ilhami
authors.initials: I
authors.lastname: Uslu
authors.forename: Adil
authors.initials: A
authors.lastname: Al-Nahhas
authors.forename: Alberto
authors.initials: A
authors.lastname: Cuocolo
authors.forename: José M
authors.initials: JM
authors.lastname: Carril
authors.forename: Ferahnaz
authors.initials: F
authors.lastname: Cinaral
authors.forename: Sherif
authors.initials: S
authors.lastname: El-Refaei
authors.forename: Mustafa
authors.initials: M
authors.lastname: Senocak
mesh_terms: D016477:Artifacts; D004383:Duodenogastric Reflux / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D016683:Supine Position; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014057:Tomography, X-Ray Computed
chemical_list: D017256:Technetium Tc 99m Sestamibi