Md. Keiper et al., MR IDENTIFICATION OF WHITE-MATTER ABNORMALITIES IN MULTIPLE-SCLEROSIS- A COMPARISON BETWEEN 1.5 T AND 4 T, American journal of neuroradiology, 19(8), 1998, pp. 1489-1493
Citations number
36
Categorie Soggetti
Clinical Neurology","Radiology,Nuclear Medicine & Medical Imaging
BACKGROUND AND PURPOSE: Although MR spectroscopy and functional MR ima
ging of the brain have been successful at 4 T, conventional fast spin-
echo imaging of the brain at 4 T has not been adequately evaluated. Th
e purpose of this study was to compare the detection of white matter a
bnormalities in multiple sclerosis (MS) at 1.5 T and 4 T. METHODS: Fif
teen patients with clinically definite MS were imaged at both 1.5 T an
d 4 T within a 1-week period. Comparison was made between fast spin-ec
ho long-TR images at both field strengths. Pulse sequences were tailor
ed to maximize resolution and signal-to-noise ratio in clinically rele
vant imaging times (< 7 min). Four interpreters independently reviewed
the images obtained at both field strengths in separate sessions and
evaluated them for lesion identification, size, characterization, and
subjective resolution. Differences in interpretations at 1.5 T and 4 T
were subsequently recorded. RESULTS: Images obtained at 4 T showed a
mean of 88 more lesions as compared with images obtained at 1.5 T. All
the lesions measured less than 5 mm and were typically aligned along
perivascular spaces. Twenty-five consensually identified lesions on 4-
T images were not seen at all on 1.5-T images. Moreover, 4-T images sh
owed 56 additional consensually identified lesions, which were indisti
nct and seen only in retrospect on 1.5-T images. These lesions were fr
equently (n = 48) identified in large confluent areas of white matter
signal intensity abnormality at 1.5 T. All observers also agreed that
4-T images subjectively enhanced the perception of normal perivascular
spaces and small perivascular lesions. CONCLUSION: MR imaging at 4 T
can depict white matter abnormalities in MS patients not detectable at
1.5 T through higher resolution with comparable signal-to-noise ratio
and imaging times.