Susceptibility weighted imaging (SWI) can exploit the magnetic susceptibility differences of various tissues. SWI is more sensitive in detection of susceptibility effects and depicts significantly more small hemorrhagic lesions than does the conventional GRE sequence.Intracranial hemorrhage (ICH) looks dark blooming on SWI. However, pattern of ICH on phase images has not been well known. The purpose of this study is to characterize hemorrhagic lesions on phase images of SWI.

We retrospectively enrolled patients with ICH who underwent both SWI and precontrast CT between 2011 and 2013 (n=43).SWI was taken using 3-Teslar system and phase map was generated after postprocessing. SWI was obtained with 3-dimensional gradient echo, according to the following parameters: FA=15, a repetition time(TR) of 28ms, an echo time(TE) of 20 ms, a 320 x 320 acqusition matrix, a field of view of 23 x 23 cm, a slice thickness of 2 mm. Types of hemorrhage were determined and stages of hemorrhage were...

Four types of hemorrhage are observed: subdural and epidural (acute, n=3; subacute, n=10; and chronic, n=4); subarachnoid (acute, n=5); parenchymal hemorrhage (acute, n=2; subacute, n=13); and microbleed (n=40). Subdural hemorrhage and epidural hemorrhage showed heterogeneous mixed bright and dark pattern in acute and early subacute stage; and homogeneous gray on phase images in late subacute and chronic stage. All acute subarachnoid hemorrhage showed bright on phase images without aliasing. All parenchymal hemorrhages more than 5-mm showed aliasing pattern on phase images regardless of hemorrhagic stage,...

Calcification can be differentiated from hemorrhage on phase images on the basis of differences in susceptibility effects. Other clinical application of phase images ,more recently, researchers have shown that changes in iron content of the brain can be monitored by using phase images. But, pattern of ICH on phase images has not been well known, as dark blooming pattern. In our hospital, pattern of hemorrhage in phase images of SWI showed variable difference according to type, stage, and size.

Y. J. LEE, H. S. Choi, B.-Y. Kim, J. Jang, S. L. Jung, K. J. Ahn, B. S. Kim; Seoul/KR mail to: [email protected]

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