Objectives. We conducted an initial clinical trial of a newly developed car
diac magnetic resonance imaging (CMRI) system. We evaluated left ventricula
r (LV) function in 85 patients to compare the clinical utility of the CMRI
system with echocardiography, the current noninvasive gold standard.
Background. Conventional CMRI systems require cardiac-gating and respirator
y compensation to synthesize a single image from data acquired over multipl
e cardiac cycles, In contrast, the new CMRI system allows continuous real-t
ime dynamic acquisition and display of any scan plane at 16 images/s withou
t the need for cardiac gating or breath-holding.
Methods. A conventional 1.5T Signa MRI Scanner (GE, Milwaukee, Wisconsin) w
as modified by the addition of an interactive workstation and a bus adapter
. The new CMRI system underwent clinical trial by testing its ability to ev
aluate global and regional LV function. The first group (A) consisted of 31
patients with acceptable echocardiography image quality. The second group
(B) consisted of 31 patients with suboptimal echocardiography image quality
. The third group (C) consisted of 29 patients with severe lung disease or
congenital cardiac malformation who frequently have suboptimal echo study.
Two independent observers scored wall motion and image quality using the st
andard 16-segment model and rank order analysis.
Results. CMRI evaluation was complete in less than 15 min. In group A, no s
ignificant difference was found between ECHO and CMRI studies (p = NS). In
group B, adequate visualization of wall segments was obtained 38% of the ti
me using ECHO and 97% of the time using CMRI (p < 0.0001). When grouped int
o coronary segments, adequate visualization of at least one segment occurre
d in 18 of 30 patients (60%) with ECHO and in all 30 patients (100%) with C
MRI (p < 0.0001). In group C, adequate visualization of the wall segments w
as obtained in 58% (CI 0.53-0.62) of the time using echocardiography and 99
.7% (CI 0.99-1.0) of the time using CMRI (p < 0.0001).
Conclusions. The new CMRI system provides clinically reliable evaluation of
LV function and complements suboptimal echocardiography. In comparison wit
h the conventional CMRI, the new CMRI system significantly reduces scan tim
e, patient discomfort and associated cost. (J Am Coil Cardiol 1998;32:2049-
56) (C) 1998 by the American College of Cardiology.