title: Scintigraphic imaging of endothelium-dependent vasodilation in the forearm: a preliminary report.
abstract: BACKGROUND
  The diagnosis of endothelial dysfunction has been gaining clinical importance, but although endothelial function testing is available in the research setting, no technique yet exists that is simple, safe, reproducible and easily performed as a clinical screening method. The aim of this study was to design a new, scintigraphic method of imaging the flow-mediated dilation in the forearm, which represents the functional characteristic of endothelial dysfunction.
  
  
  RESULTS
  The study group comprised 118 subjects in whom left forearm ischemia was induced by inflating a sphygmomanometer cuff to supra systolic pressure for 4.5 min. Later, dynamic acquisition (2 s frame/min) was initiated after the injection of technetium-99m methoxy-isobutyl isonitril into the dorsal pedal veins. Equivalent regions of interest were drawn on both arms to detect total activity counts during 1 min and the perfusion ratios (left arm/right arm) were calculated. The left arm counts (22,203.3+/-12,372.7) were significantly higher than the right arm counts (9,980.9+/-5,931.9) (p<0.001). A significant decrease in perfusion ratios was noted in the hypertension and hypercholesterolemia groups. An increase in the number of risk factors caused an insignificant decrease in perfusion ratio (p=0.346).
  
  
  CONCLUSIONS
  Non-invasive evaluation of endothelium-dependent vasodilation by semiquantitative scintigraphic method using radioactive perfusion tracer provided promising results.
authors.affiliation: Department of Nuclear Medicine, Gulhane Military Medical Academy and School of Medicine, Etlik-Ankara, Turkey. aokaracali@yahoo.com
authors.forename: Alper O
authors.initials: AO
authors.lastname: Karacalioglu
authors.forename: Sait
authors.initials: S
authors.lastname: Demirkol
authors.forename: Ozdes
authors.initials: O
authors.lastname: Emer
authors.forename: Turgay
authors.initials: T
authors.lastname: Celik
authors.forename: Selim
authors.initials: S
authors.lastname: Kilic
authors.forename: Seyfettin
authors.initials: S
authors.lastname: Ilgan
authors.forename: Mehmet A
authors.initials: MA
authors.lastname: Ozguven
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003627:Data Interpretation, Statistical; D004730:Endothelium, Vascular / Q000502:physiology* / Q000503:physiopathology; D005260:Female; D005542:Forearm / Q000098:blood supply*; D006801:Humans; D006937:Hypercholesterolemia / Q000503:physiopathology; D006973:Hypertension / Q000503:physiopathology; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D011446:Prospective Studies; D011849:Radioactive Tracers; D011877:Radionuclide Imaging / Q000295:instrumentation / Q000379:methods*; D012039:Regional Blood Flow / Q000502:physiology; D015203:Reproducibility of Results; D013667:Technetium; D014664:Vasodilation / Q000502:physiology*
chemical_list: D011849:Radioactive Tracers; D013667:Technetium