Helical CT angiography with maximum intensity projection in the assessmentof aortic coarctation after surgery

OBJECTIVE. The value of CT angiography and three-dimensional (3D) reconstru ctions was investigated in the postoperative care after surgical repair of aortic coarctation and compared with conventional angiography. SUBJECTS AND METHODS, Twenty-five patients referred because of suspicion of stenosis in the area of former coarctation were prospectively studied with CT angiography and catheter angiography. We determined the morphometric an d morphologic findings such as aortic diameter, stenosis, aneurysm, intimal flaps, circumscribed pouch, or arteriosclerotic plaques with 3D reconstruc tions, using maximum-intensity-projection (MIP) technique and catheter angi ography. The results of both techniques were compared. The ratio of the nar rowest diameters of the former coarctation and the descending aorta was cor related with the systolic pullback blood pressure gradient in all patients. RESULTS. The former coarctation was normal in 11 patients, (44%), group A: narrowed in 12 children (48%), group B; and dilated in two children (8%), g roup C. An intimal flap and a circumscribed pouch were delineated in four s ubjects. MIP reconstructions and catheter angiography revealed identical re sults regarding the classification into groups A, B, C; intimal flaps; and circumscribed pouches. Statistical analysis revealed good correlation betwe en the narrowest aortic diameters measured on MIP reconstructions and cathe ter angiography, whereas no correlation between the systolic pullback blood pressure gradient and the diameter ratio of the former coarctation and the descending aorta was found. CONCLUSION. CT angiography and 3D reconstructions using MIP represent a rel iable noninvasive technique to replace diagnostic catheter angiography in t he postoperative care of patients with coarctation and provide the clinicia n with valuable information concerning further invasive procedures.