High temporal resolution SSFP cine MRI for estimation of left ventricular diastolic parameters.
OBJECTIVE
To obtain high temporal resolution (HTR) magnetic resonance (MR) steady-state free-precession (SSFP) cine cardiac images by using multichannel radiofrequency (RF) hardware and parallel imaging techniques; to study the effect of temporal resolution; and to compare the derived left ventricular (LV) diastolic filling parameters with echocardiographic results.


METHODS
HTR images were acquired in 13 healthy volunteers using a 1.5 T scanner with 32 RF channels and sensitivity encoding (SENSE) and k-t broad-use linear-acquisition speedup technique (k-t BLAST) imaging techniques. LV diastolic parameters were calculated and compared to conventional echocardiographic indices such as the isovolumic relaxation time (IVRT) and E/A ratio. The need for HTR was assessed and the MR results were compared with echocardiographic results.


RESULTS
The HTR (approximately 6-ms) images yielded higher peak filling rates, peak ejection rates, and peak atrial filling rates. A progressive decline in filling and ejection rates was observed with worsening temporal resolution. The IVRTs and E/A ratios measured with MR versus echocardiography were in broad agreement. Also, SENSE and k-t BLAST yielded similar diastolic functional parameters.


CONCLUSIONS
With SENSE or k-t BLAST and modern hardware, HTR cine images can be obtained. The lower temporal resolutions (30-50 ms) used in clinical practice reduce LV filling rates by <or=30% and may hinder characterization of transient phenomena such as the IVRT.
Krishnamurthy
Ramkumar
R
Department of Bioengineering, Rice University, Houston, Texas, USA.
Pednekar
Amol
A
Cheong
Benjamin
B
Muthupillai
Raja
R
D000328:Adult; D000465:Algorithms; D003971:Diastole; D004452:Echocardiography / Q000379:methods; D005260:Female; D006352:Heart Ventricles / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D013997:Time Factors; D018487:Ventricular Dysfunction, Left; D016277:Ventricular Function, Left