Simple techniques to reduce bowel activity in cardiac SPECT imaging.
OBJECTIVE
Scatter from the bowel degrades image quality in 99mTc sestamibi myocardial perfusion imaging (MPI). Iodinated oral contrast, which has been used to outline bowel in medical imaging, absorbs X-rays as well as gamma rays. The purpose of this study was to test our hypothesis that iodinated oral contrast during MPI would absorb gamma rays emitted from 99mTc sestamibi in the bowel, thereby reducing scatter and improving cardiac SPECT images.


RESULTS
Thirty subjects undergoing adenosine stress 99mTc sestamibi cardiac SPECT were randomized to receive either iodinated oral contrast (IOC), water or no intervention (controls). Subjects had 1 day rest-stress MPI using the adenosine stress protocol. Images were analysed using infra-cardiac counts, image variability, image contrast and the ratios of anterior to inferior and septal to lateral walls. The improvement in image contrast and variability between first and second images were significant in both the IOC and water groups. The IOC group had a more significant improvement in variability than did the water group. The reduction in infra-cardiac counts was also more significant in the IOC group.


CONCLUSIONS
The use of oral contrast and water improved the image variability and contrast by decreasing the infra-cardiac scatter. The improvement was even more significant in the oral contrast group.
Iqbal
Syed M
SM
Division of Cardiology, Department of Medicine, Bronx-Lebanon Hospital Center, Montefiore Medical Center and Albert Einstein College of Medicine, New York 10457, USA.
Khalil
Mohammed E
ME
Lone
Bashir A
BA
Gorski
Robert
R
Blum
Steve
S
Heller
Eliot N
EN
D000241:Adenosine / Q000378:metabolism; D000284:Administration, Oral; D000368:Aged; D003287:Contrast Media / Q000494:pharmacology; D005260:Female; D005720:Gamma Rays; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007422:Intestines / Q000187:drug effects / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000473:pathology*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D017256:Technetium Tc 99m Sestamibi; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014867:Water; D014965:X-Rays
D003287:Contrast Media; D019275:Radiopharmaceuticals; D014867:Water; D017256:Technetium Tc 99m Sestamibi; D000241:Adenosine