PubMed Health⌕ Search

Biomedical subjects

B B Iskandrian

Publications and source records attributed to B B Iskandrian.

2 recordsLinked to original sources

Tomographic myocardial perfusion imaging with technetium-99m teboroxime during adenosine-induced coronary hyperemia: correlation with thallium-201 imaging.

Single-photon emission computed tomographic imaging with technetium-99m teboroxime during exercise has been found to be feasible and the results correlate with those obtained with thallium-201. This study examined the feasibility of this technique and compared tomographic imaging with technetium-99m teboroxime during adenosine-induced coronary hyperemia with thallium-201 imaging. With the patient positioned on the imaging table, adenosine was infused at a rate of 140 micrograms/kg per min for 6 min. At 4 min, 20 to 25 mCi (740 to 925 MBq) of technetium-99m teboroxime was injected intravenously and imaging was started as soon as the infusion was completed with use of a 180 degrees anterior arc and 32 stops at 10 s/stop (total imaging time 7.8 min). Rest images were obtained 60 to 90 min later with use of a similar dose of technetium-99m teboroxime. Exercise tomographic thallium images were obtained within 2 weeks of the teboroxime studies. In the 20 patients studied, the teboroxime images were normal in 2 (50%) of 4 normal subjects and abnormal in 15 (94%) of 16 patients with coronary artery disease; 4 of the 15 had a fixed defect and 11 a reversible defect. There was agreement between teboroxime and thallium studies in 16 patients (80%), in 319 (80%) of 400 segments and in 50 (83%) of 60 vascular segments (p less than 0.05). In two normal subjects, an apparent fixed defect involving the inferior wall was seen on the teboroxime but not the thallium images and was thought to be due to an attenuation artifact secondary to extracardiac activity in the left lobe of the liver.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗

Comparison of same-day protocols using technetium-99m-sestamibi myocardial imaging.

Two same-day protocols (rest/exercise [Protocol 1] and exercise/rest [Protocol 2]) with sestamibi (hexakis 2-methoxy-2-isobutyl-isonitrile) were performed within 2 to 14 days of each other after randomization. The initial study in each protocol was done using a dose of 185-296 MBq of 99mTc-sestamibi. The second study in each protocol used a dose of 555-925 MBq. SPECT imaging was started 30 to 60 min after injection using a 180 degrees anterior arc. Segmental analysis was interpreted as normal, scar or ischemia (20 segments/patient). Among the protocols, there was concordance in 93% of the segments (593/640 segments). In the 11 patients with coronary artery disease and no prior myocardial infarction who had ischemic abnormality, count densities from abnormal and normal zones were compared between the two protocols. Protocol 1 showed greater count differences between abnormal and normal zones on exercise images with better normalization of abnormality on rest images than Protocol 2 (p less than 0.05). Technetium-99m-sestamibi provides high quality images using either of the two same-day protocols. However, the rest/exercise protocol provides better image contrast and ability to detect reversibility of perfusion defects, and is the preferred same-day protocol.

Ambulatory Care↗