Improvement of brain lesion detection at 0.1 T by simultaneous use of Gd‐DTPA and magnetization transfer imaging

Abstract

Imaging parameters were optimized at 0.1 T to improve contrast-to-noise ratios (CNR) when combining magnetization transfer (MT) imaging and the use of paramagnetic contrast medium. This was accomplished by imaging a phantom containing serial concentrations of Gd-DTPA in cross-linked bovine serum albumin. With the use of simulations, the dependence of CNR on imaging parameters was studied. Conventional and MT images were obtained from 10 brain tumor patients with single and triple doses of Gd-DTPA. Simulations demonstrated the importance of TR in postcontrast sequences. The CNR in MT images is less sensitive to TR than in conventional images. A significant CNR improvement caused by MT remains at longer TR when there is no contrast enhancement without MT. The clinical results indicate that a single dose of Gd-DTPA combined with MT cannot replace imaging with a triple dose. However, MT significantly improved the CNR after single and triple Gd-DTPA-doses on T1-weighted and proton-density images.

Spin lock and magnetization transfer imaging of head and neck tumors.

“…Tanttu et al (1992) and Kurki et al (1992) were among first investigators to suggest that MT could have synergistic action with Gd-DTPA at 0.1 T. The contrast of enhancing brain lesions can be improved by suppressing unenhancing surrounding tissues with MT pulse and simultaneously reducing the signal suppression of the lesion with paramagnetic agent that shortens T1. The combined use of MT and Gd-DTPA has been shown to increase the contrast in brain lesion imaging in several studies , Kurki et al 1992, Finelli et al 1994, Mehta et al 1995, Abo Ramadan et al 1997. Finelli et al (1994) and Mehta et al (1995) demonstrated an approximate doubling of enhancing lesion CNR with MT for a variety of CNS lesions and CNR of the same order as triple dose of Gd-DTPA.…”

“…Finelli et al (1994) and Mehta et al (1995) demonstrated an approximate doubling of enhancing lesion CNR with MT for a variety of CNS lesions and CNR of the same order as triple dose of Gd-DTPA. In a study with low field strength (0.1 T) a significant but not as remarkable increase in brain tumor CNR was found with combined use of MT and Gd-DTPA (Abo Ramadan et al 1997). Using the background suppression capability MT technique has been exploited in MR angiography (Edelman et al 1992,) and also for contrast improvement in liver neoplasms (Outwater et al 1992, Kahn et al 1993, Halavaara et al 1998, breast (Flamig et al 1992), normal knee (Wolf et al 1991) and heart ).…”