LIVER MR-IMAGING - COMPARISON OF RESPIRATORY TRIGGERED FAST SPIN-ECHOWITH T2-WEIGHTED SPIN-ECHO AND INVERSION-RECOVERY

Background: The purpose of this study was to compare a fast spin-echo sequence combined with a respiratory triggering device (R. trig. FSE) with conventional T2-weighted spin-echo (CSE) and inversion recovery ( STIR) sequences for the detection of focal hepatic lesions. Methods: W e performed a prospective study of 33 consecutive patients with known or suspected hepatic tumors. All patients underwent R. trig. FSE, CSE, and STIR imaging at 1.5 T. Acquisition times were 10.7 min for the CS E sequence and ranged from 12 to 15 min for STIR and from 5 to 7 min f or R. trig FSE. For each sequence, liver-spleen contrast-to-noise rati o (CNR) and liver-lesion CNR were determined quantitatively. Image art ifact and sharpness were graded by using a four-point scale on each se quence by two independent readers. Both readers also independently ide ntified hepatic lesions (up to a maximum of eight per patient). For pa tients with focal lesions, the total number of lesions detected (on ea ch sequence) and the minimum size of detected lesions were also determ ined by each reader. Results: No significant difference was detected b etween R. trig. FSE and CSE or STIR in either liver-spleen CNR or live r-lesion CNR. R. trig. FSE images were equivalent to CSE and superior to STIR in sharpness (p < 0.01) and presence of artifact (p < 0.01). R . trig. FSE detected a higher number of lesions (reader 1: n = 92, rea der 2: n = 86) than CSE (reader 1: n = 70, reader 2: n = 69) and a sig nificantly higher number than STIR (reader 1: n = 71, reader 2: n = 76 ). Lesion structure was significantly better defined with R. trig. FSE than with STIR (p ( 0.01) and CSE (p < 0.05). Conclusions. Compared w ith CSE and STIR, R, trig. FSE produces hepatic images of comparable r esolution and detects an increased number of focal hepatic lesions in a shorter period of time.