Freddy Ståhlberg
Expert
Brain lesion contrast in MR imaging. Dependence on field strength and concentration of gadodiamide injection in patients and phantoms
Författare
Summary, in English
PURPOSE: To compare the contrast effects of gadodiamide injection at 0.3 and at 1.5 T, at different concentrations in phantoms, and to correlate the results to clinical doses used for examining brain lesions. MATERIAL AND METHODS: Gel phantoms with T1 and T2 corresponding to brain gray matter were doped with different concentrations of gadodiamide injection and examined with T1-weighted sequences. Two different sets of phantoms were used, one for 0.3 T and one for 1.5 T. To express contrast, a quotient (RATIOphantom) between signals in each tube with gadodiamide injection and in the one without it was calculated. A corresponding quotient (RATIOpatient) between signals in brain metastases and in gray matter was calculated in 16 patients examined at 0.3 T (0.1 and 0.3 mmol Gd/kg b.w.) and in 5 patients examined at 1.5 T (0.1 mmol Gd/kg b.w.). RESULTS: Maximum RATIOphantom and RATIOpatient were more than 50% higher at 1.5 T than at 0.3 T at equal concentrations using heavily T1-weighted sequences. The use of SE TR/TE 600/30 instead of 400/25 reduced the contrast effect 15-45% depending on concentration. Comparing RATIOpatient to RATIOphantom suggests that the maximum T1 effect of Gd contrast media occurs at higher doses than in current clinical use, as at 0.1 mmol/kg b.w. we achieved 38% (0.3 T) and 56% (1.5 T) of the maximum phantoms. At 0.3 mmol/kg b.w. we achieved 63% (0.3 T) of the theoretical maximum. CONCLUSION: The contrast effect of Gd contrast media is higher at 1.5 T than at 0.3 T. Higher doses than presently used might prove useful especially at lower field strengths where the contrast effect of Gd is less pronounced. Heavy T1-weighting is also important.
Avdelning/ar
- Diagnostisk radiologi, Malmö
- Diagnostisk radiologi, Lund
Publiceringsår
1997
Språk
Engelska
Sidor
14-18
Publikation/Tidskrift/Serie
Acta Radiologica
Volym
38
Issue
1
Dokumenttyp
Artikel i tidskrift
Förlag
SAGE Publications
Ämne
- Radiology, Nuclear Medicine and Medical Imaging
Status
Published
Forskningsgrupp
- Radiology Diagnostics, Malmö
ISBN/ISSN/Övrigt
- ISSN: 1600-0455