1354849 - Diagnostic confidence with quantitative CMR perfusion mapping increases with increased coverage of the left ventricle

Fully quantitative CMR perfusion mapping based on dynamic first-pass perfusion enables pixelwise myocardial perfusion quantification in ml/min/g.¹ Perfusion maps are conventionally acquired in three short-axis slices (basal, mid and apical) of the left ventricle (LV) to allow for assessment of myocardial perfusion in 16 of the 17 LV segments.² Still, a significant part of the LV myocardium, including the apex, is not covered with only 3 short-axis slices. The aim of this study was to assess if an increased LV coverage either by adding three long-axis slices (2-, 3-, and 4-chamber views) or an additional three short-axis views in addition to the conventional three short-axis views would increase the diagnostic confidence when interpreting quantitative perfusion maps.

Methods:

A total of 214 patients, referred for clinical CMR with quantitative perfusion to Lund University Hospital, were included in the study with written informed consent for participation. All patients underwent an imaging protocol including perfusion mapping at rest and during adenosine stress. Six perfusion views were acquired in all patients. In 105 patients six equidistant short-axis slices covering the LV were acquired whereas in 109 patients, three long-axis views (2-, 3-, and 4-chamber) where added to the three conventional short-axis views. All datasets (n=214 x 2) were read by an experienced observer both with access only to the three conventional short-axis views and also with all six views in random order with the observer blinded to all other patient data. The diagnostic confidence for ruling in or out stress-induced ischemia was scored according to a Likert scale (certain ischemia [2 points], probably ischemia [1 point], uncertain [0 points], probably no ischemia [1 point], certain no ischemia [2 points]).

Results:

The diagnostic confidence score increased significantly when increasing the number of perfusion views from three to six (1.25 ± 0.69 vs 1.56 ± 0.64, p < 0.001). Of the 214 patients, 39 had signs of single-vessel disease, 11 multi-vessel disease, 15 coronary microvascular dysfunction, and 5 hypertrophic cardiomyopathy. The number of cases where the observer was certain to rule in or out stress-induced ischemia increased both when adding three long-axis views (Figure 1A-B) and an additional three short-axis views (Figure 1C-D). An examples where diagnostic confidence increased by adding three long-axis views is shown in Figure 2.  

Conclusion:

The diagnostic confidence for stress-induced ischemia with quantitative CMR perfusion mapping increases with increased LV coverage from three to six views. Thus, future development and clinical implementation of quantitative CMR perfusion should aim at increasing the number of views from the current conventional three short-axis views.