Abstract 4210: Evaluation of Coronary Stenoses and their Functional Significance in Patients with Known and Suspected Coronary Artery Disease using MRI and CTA
Objectives: Non-invasive computed tomography coronary angiography (CTA) is an accurate anatomic imaging technique, but cannot assess the hemodynamic severity of the detected atherosclerotic lesions. In patients with abnormal CTA, optimal treatment strategy may therefore remain uncertain. The purpose of the current study was to compare anatomic observations with CTA to functional assessment with MRI in patients with known and suspected CAD.
Methods: In this prospective study, 55 patients (62% male, average age 57±9 years, pre-test likelihood low to intermediate 62%) underwent 64-slice CTA and 1.5 Tesla MRI within 40 days. The presence of CAD (normal <30% stenosis, non-significant 30%–50% stenosis, and significant >50% stenosis) was determined on CTA and first pass perfusion during adenosine stress was assessed on MRI.
Results: CTA was normal in 15 (27%), non-significant in 24 (44%) and significant in 16 (29%) patients. MRI revealed a perfusion defect in 21 (38%) patients, and was normal in 34 (62%). Table 1⇓ shows the CTA results for patients with normal and abnormal perfusion on MRI. CTA was abnormal in almost all patients with an abnormal perfusion. However, a normal perfusion MRI study was associated with abnormal CTA in a large proportion of patients, as non-significant and significant CAD was noted in 15 (44%) and 5 (15%) patients respectively.
Conclusion: Although abnormal perfusion on MRI correlated well with abnormal CTA, underlying CAD is present in the majority of patients with a normal MRI perfusion study. The combination of both techniques may allow more refined characterization of CAD.