title: Longer Tc-99m-mebrofenin labeling-to-administration time results in scintigraphic underestimation of liver function.
abstract: OBJECTIVE
  Tc-99m-mebrofenin clearance rate is used to estimate hepatocellular function. This investigation studied effect of labeling-to-administration (LTA) time of Tc-99m-mebrofenin and its liver clearance rate.
  
  
  METHODS
  A total of 15 patients, age 46 ± 13 (range, 19-69) years, referred for routine gallbladder ejection fraction testing, were retrospectively studied. All had tests associated to normal liver, and no medical history of liver diseases was observed. Tc-99m-mebrofenin scintigraphic liver clearance (MSLC) rate was determined by the standard technique based on liver uptake rate. The radiopharmaceutical was prepared at an off-site central radiopharmacy. Linear regression was used to assess relationship of LTA time and MSLC.
  
  
  RESULTS
  The LTA was 7.6 ± 2.0 (range, 4-12) hours. The labeling efficiency was 99.0% ± 1.33%. The MSLC rate was 11.9%/min ± 2.7%/min (range, 6.4-18.3). There was an inverse relationship of LTA and MSLC, expressed in the following equation: y = -0. 97x + 19.25 (R = 0.5076, P = 0.0028). The negative correlation with LTA remained when MSLC was corrected for body surface area (R = 0.4241, P = 0.0085).
  
  
  CONCLUSIONS
  There is a significant underestimation of MSLC with increasing LTA time. If liver function assessment is the purpose of a hepatobiliary study, Tc-99m-mebrofenin should be administered as close to the time of radiopharmaceutical preparation as possible, preferably within 1 hour.
authors: Department of Radiology, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey, PA, USA. mtulchin@psu.edu
authors: Mark
authors: M
authors: Tulchinsky
authors: Thomas W
authors: TW
authors: Allen
mesh_terms: D000328:Adult; D000368:Aged; D000814:Aniline Compounds; D001659:Biliary Tract / Q000000981:diagnostic imaging; D005260:Female; D015637:Gated Blood-Pool Imaging; D005998:Glycine; D006801:Humans; D007098:Imino Acids / Q000008:administration & dosage*; D008099:Liver / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008111:Liver Function Tests; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds / Q000008:administration & dosage*; D011877:Radionuclide Imaging; D013997:Time Factors; D055815:Young Adult
chemical_list: D000814:Aniline Compounds; D007098:Imino Acids; D015609:Organotechnetium Compounds; C034837:technetium Tc 99m mebrofenin; D005998:Glycine