99Tcm-MIBI gated myocardial perfusion imaging in patients with myocardial bridging diagnosed by CT angiography

Objective To explore the clinical value of 99Tcm-MIBI G-MPI in patients diagnosed with myocardial bridging(MB) by CTA. Methods Forty-five patients with MB and 17 normal controls diagnosed by CTA(64 slices CT) were included. All patients underwent rest 99Tcm-MIBI G-MPI and 17 MB patients and 9 normal controls also underwent stress 99Tcm-MIBI G-MPI. Myocardial ischemia, function and wall motion were assessed. G-MPI results were compared with CTA results by χ2 test, Fisher exact test and t test. Results In patients with MB, the positive rate of abnormal perfusion by gated stress 99Tcm-MIBI G-MPI was 64.7% (11/17) and 41.2% (7/17) using quantitative analysis and visual evaluation respectively; while the data were 42.2% (19/45) and 22.2% (10/45) by rest G-MPI (P=0.035). The positive rate by rest G-MPI in MB patients was significant different among mural coronary arteries of different depths and different locations. By quantitative analysis of the stress G-MPI, the reversible, fixed, and mixed ischemia patients were 4 (35.3%), 6 (23.5%) and 1 (5.9%) respectively; the reversed, reversible and fixed abnormity of wall motion was found in 4 (23.5%), 4 (23.5%) and 2 (11.8%) patients respectively; the reversed, reversible and fixed wall thickening were found in 6 (35.3%), 5 (29.4%) and 1 (5.9%) patients respectively. There was no significant difference in left ventricular ejection fraction and peak filling rate between MB patients and normal controls in both rest and stress studies (t: from -0.564 to 1.292, all P>0.05). Conclusion The G-MPI may be useful for the evaluation of myocardial ischemia and myocardial function simultaneously in patients with MB. Key words: Myocardial bridging;  Tomography, emission-computed, single-photon;  Tomography, X-ray computed;  MIBI