A head-to-head comparison between 64-slice multidetector computed tomographic and conventional coronary angiographies...

It has been suggested that multidetector computed tomographic coronary angiography (MDCT-CA) may be a reliable modality for the diagnosis and assessment of myocardial bridge (MB). However, the correlation between MB measurements of MDCT-CA and conventional coronary angiography (CCA) has not been determined.

We assessed the correlation between MDCT-CA and CCA in MB measurements. One hundred twenty consecutive patients (77 men, 61±12 yrs) underwent MDCT-CA and CCA simultaneously from suspected coronary artery disease. MB measurements on MDCT-CA included location, length, depth, within-MB diameter, reference luminal diameters of segment proximal and distal MB, and luminal narrowing. MB measurements on CCA included length, within-MB diameter, reference lumen diameters of segment proximal and distal to MB, and luminal narrowing.

We observed 38 MB segments in 30 patients (25%), with 6 patients having ≥2 MB segments. The within-MB diameters on MDCT-CA and CCA showed a significant correlation during systolic (1.3±0.3 mm vs. 1.2±0.5 mm: r=0.394, P=0.028) and diastolic phases (1.4±0.4 mm vs. 1.6±0.6 mm: r=0.524, P=0.001). Systolic luminal narrowing (SLN) on CCA ranged from 8% to 75% (38±16%), and a definite milking effect (defined as SLN>50%) was observed in only 7 segments (18.4% of 38 MBs, or 5.8% of all cohorts). In case of MB segments with a definite milking effect, length of MBs on MDCT-CA and CCA correlated significantly (systolic phase: r=0.794, P=0.033 and diastolic phase: r=0.766, P=0.045). SLN on CCA was not related with any MB measurement on MDCT-CA.

In case of MBs with sufficient systolic compression, diameter and length of MBs correlates significantly between MDCT-CA and CCA analysis. The detection rate of MB on CCA may be associated with the degree of systolic compression, and systolic compression on CCA cannot be predicted by any measurement on MDCT-CA.