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Low‐contrast focal lesion detectability phantom for 1 H MR imaging
Author(s) -
Madsen Ernest L.,
Blechinger Joseph C.,
Frank Gary R.
Publication year - 1991
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.596659
Subject(s) - imaging phantom , nuclear medicine , magnetic resonance imaging , physics , lesion , contrast (vision) , nuclear magnetic resonance , medicine , radiology , optics , pathology
A phantom made from tissue‐mimicking materials is reported for testing 1 H MRI systems regarding their ability to detect small low‐contrast focal lesions and to delineate the boundaries of larger lesions. Two sets of seven spherical simulated lesions with diameters of 2, 3, 4, 5, 6.3, 7.9, and 9.5 mm have T 1 and T 2 values somewhat higher than the corresponding values in the surrounding simulated normal tissue. Relaxometer determinations of T 1 and T 2 for the simulated normal tissue yielded 955 and 106 ms, respectively, at 22 °C and 1 T. The corresponding values in set ♯1 of the simulated lesions were 1017 and 175 ms and in set ♯2 were 1002 and 127 ms. These T 1 and T 2 values are similar to those for brain and brain lesions but are too high to represent soft tissue such as liver and muscle. The centers of the 14 lesions are coplanar, and eight alignment devices surround them facilitating superposition of the scan plane and the plane containing the centers of the lesions. Illustrative images made with a 1.5‐T system are shown. All simulated lesions are detectable in T 2 ‐weighted head coil images. Corresponding T 1 ‐weighted images are also shown, the 2‐ and 3‐mm lesions of set ♯2 and the 2‐mm lesion of set ♯1 not being detectable. The phantoms could be useful for performance or acceptance testing and perhaps for quality assurance testing.