A comparison of three radionuclide myocardial perfusion tracers in clinical practice: the ROBUST study.
There are no large studies available to guide the selection of thallium (Tl), methoxyisobutylisonitrile (MIBI) or tetrofosmin (Tf) for myocardial perfusion imaging. Our objective was to compare the technical and clinical performance of the three in routine clinical practice. We randomised 2,560 patients to receive Tl, MIBI or Tf. A 1-day stress/rest protocol was used for MIBI and Tf. Tracer uptake was scored using a 17-segment model, quality and artefact scores were assigned, and ratios of heart (H), liver (L), subdiaphragmatic (S) and lung activity were measured. Mean quality scores (stress/rest) were Tl 2.13/2.16, MIBI 2.18/2.39, Tf 2.18/2.42 ( P=ns stress and <0.00001 rest). For attenuation artefact, Tl>MIBI=Tf ( P<0.05) and for low-count artefact Tl>MIBI>Tf ( P<0.001). For H/S, Tl>MIBI=Tf, for H/L Tl>MIBI=Tf, and for H/lung Tl<MIBI=Tf. Stress defects in the patients with reversible or mixed perfusion defects were more severe for Tl than for the other tracers (mean summed score out of 68: Tl 52.3, MIBI 55.7, Tf 54.4, P<0.01), but mean rest scores were more similar (Tl 58.7, MIBI 60.7, Tf 59.4, P=0.02). In the subset of 137 patients undergoing diagnostic perfusion studies without prior infarction, angiography or revascularisation, overall sensitivity for the detection of coronary disease defined by subsequent angiography was 91% with a specificity of 87%. There were no significant differences between the tracers with regard to sensitivity and specificity.


CONCLUSIONS
There are technical differences between the tracers. Overall image quality score is superior using technetium, with less low-count artefact and less attenuation. Stress defect depth and extent are slightly greater using thallium, with no difference between MIBI and tetrofosmin. All three tracers perform well in clinical terms, with high sensitivity and specificity for angiographic stenosis and no differences in accuracy between the tracers.
Kapur
Akhil
A
Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK.
Latus
Katherine A
KA
Davies
Glyn
G
Dhawan
Rhanju T
RT
Eastick
Sian
S
Jarritt
Peter H
PH
Roussakis
George
G
Young
Melanie C
MC
Anagnostopoulos
Constantinos
C
Bomanji
Jimmy
J
Costa
Durval C
DC
Pennell
Dudley J
DJ
Prvulovich
Elizabeth M
EM
Ell
Peter J
PJ
Underwood
S Richard
SR
D000241:Adenosine; D016477:Artifacts; D003327:Coronary Disease / Q000000981:diagnostic imaging; D003430:Cross-Sectional Studies; D004280:Dobutamine; D005080:Exercise Test; D006321:Heart / Q000000981:diagnostic imaging*; D006331:Heart Diseases / Q000000981:diagnostic imaging*; D006801:Humans; D009206:Myocardium / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000493:pharmacokinetics; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D011786:Quality Control; D011859:Radiography; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi / Q000493:pharmacokinetics; D013793:Thallium / Q000493:pharmacokinetics; D006113:United Kingdom
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C027549:thallium chloride; D004280:Dobutamine; C078700:technetium tc-99m tetrofosmin; D017256:Technetium Tc 99m Sestamibi; D013793:Thallium; D000241:Adenosine