T1-weighted images with ECG gating using partial flip angle spin-echo imaging.
ECG-gated spin-echo imaging can reduce vascular artefacts compared with spin-echo scans without gating. However, this method produces poor T1-weighted images because the repetition time (TR) is limited by the heart rate. We investigated the value of low flip angle spin-echo imaging for increasing T1-dependent contrast when using ECG gating. Using computer simulation, the predicted contrast increased with decreasing the flip angle, and the effect was almost saturated at a flip angle of around 40 degrees. With the application of this flip angle, the identical image contrast as a T1-weighted image (TR = 400 ms) can be obtained within the heart rate range of 65 to 75 beats/min. For clinical evaluation, the tissue contrast index values ((signal intensity in the lesion-signal intensity in the muscle)2 x 100/signal intensity in the muscle) obtained by conventional spin-echo and low flip angle spin-echo imaging were compared in 17 patients. The contrast index of low flip angle spin-echo images (74.0 +/- 52.0) was significantly higher than that of conventional spin-echo images (40.9 +/- 35.9). Thus, ECG-gated low flip angle spin-echo imaging provided better T1-dependent contrast than conventional ECG-gated spin-echo imaging. This method may be especially useful for Gd-DTPA-enhanced magnetic resonance imaging.
Sugimura
K
K
Department of Radiology, Shimane Medical University, Izumo, Japan.
Kawamitsu
H
H
Yoshikawa
K
K
Yuasa
K
K
Kasai
T
T
Okizuka
H
H
D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis*; D003198:Computer Simulation; D003287:Contrast Media; D004562:Electrocardiography; D004938:Esophageal Neoplasms / Q000175:diagnosis*; D019786:Gadolinium DTPA; D006339:Heart Rate; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis*; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008479:Mediastinal Neoplasms / Q000175:diagnosis*; D008954:Models, Biological; D009942:Organometallic Compounds; D004369:Pentetic Acid / Q000031:analogs & derivatives
D003287:Contrast Media; D009942:Organometallic Compounds; D004369:Pentetic Acid; D019786:Gadolinium DTPA