Hepatic T2‐weighted MRI: A prospective comparison of sequences, including breath‐hold, half‐Fourier turbo spin echo (HASTE)

Abstract

The purpose of this study was to quantitatively compare the hepatic contrast characteristics of conventional spin-echo (CSE) and fast spin-echo (FSE) sequences with breath-hold T2-weighted images acquired with half-Fourier turbo spin echo (HASTE). Forty-five patients were examined with a phased-array surface coil. Nineteen patients had focal hepatic lesions, including eight malignant tumors, 10 cavernous hemangiomas, and one hepatic adenoma. Twenty-six patients had no focal hepatic lesions. T2-weighted images with comparable TE were acquired with CSE, FSE, and HASTE pulse sequences. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) for liver, spleen, and lesions were measured. FSE demonstrated significantly better quantitative performance than CSE for liver-spleen CNR (P .0084). No statistically significant difference was demonstrated between FSE and CSE for liver or spleen SNR. FSE demonstrated clear scan time and resolution advantages over CSE. HASTE performed significantly poorer than CSE and FSE for liver-spleen CNR (P < .0001), liver SNR (P = .0002 for CSE and P < .0001 for FSE), and spleen SNR (P < .0001). Optimized FSE images with a short echo train length performed comparably to CSE images of equivalent TE. Liver-lesion CNR was suppressed on HASTE images, suggesting that long echo train length FSE sequences could diminish solid lesion detection compared to CSE and short echo train length FSE.

Small-Bowel Disease: Comparison of MR Enteroclysis Images with Conventional Enteroclysis and Surgical Findings

“…However, it seems unlikely that MR imaging, even with this sequence, can produce better results than CT in patients with lowgrade partial SBO, given that the diagnosis must rely on the same criteria-that is, dilated bowel loops proximal to the site of obstruction. Although the half-Fourier RARE sequence is fast and can be performed in a breathing-independent fashion (approximately 2 seconds duration), image quality is decreased by blurring, and the soft-tissue contrast is less than that possible with breath-hold fast spinecho sequences (24), which is the technique we prefer.…”

T2‐weighted MRI of rectosigmoid carcinoma: Comparison of respiratory‐triggered fast spin‐echo, breathhold fast‐recovery fast spin‐echo, and breathhold single‐shot fast spin‐echo sequences

“…Although motion artifact was the least prominent with the BH-SSFSE sequence, poor image quality was observed because of blurring artifact, which is thought to be caused by T2-filtering effects (23)(24)(25).…”

Magnetic Resonanance Imaging of the Liver (Including Biliary Contrast Agents)—Part 2: Protocols for Liver Magnetic Resonanance Imaging and Characterization of Common Focal Liver Lesions

“…Since the early applications, FSE sequence is preferred over SSFSE because of the higher liver signal-to-noise ratio (SNR) and lesion-to-liver contrast-to-noise ratio (CNR). 6,7 In fast recovery FSE (FRFSE), 2 RF pulses at the end of the (ET) (flip angles: +180° and −90°) restore the magnetization of tissues with long relaxation times before the subsequent excitation pulse, resulting in improved SNR, CNR, and lesion conspicuity. 8,9 …”

“…In comparison with FSE and FRFSE sequences, the longer ET of SSFSE may result in lower SNR and CNR and decreased conspicuity of solid lesions due to magnetization transfer effects and blurring artifacts along the phase encoding direction. 7,8,11 The design o this sequence is suitable for acquisition with long echo time (TE) and heavy T2-weighting. 4 …”