Haiyan Lou MD, Presenter: Nothing to Disclose

Qidong Wang, Abstract Co-Author: Nothing to Disclose

Shunliang Xu, Abstract Co-Author: Nothing to Disclose

MR T2 star weighted angiography (SWAN) is a relatively new magnetic resonance imaging (MRI) sequence relying on susceptibility differences between adjacent tissues to produce an image. The presence of SWAN appearance of infection has not been well-established in previous literature. The purpose of this study was to identify the tuberculomas and meningitis during the treatment process to the formation of calcium deposits by using SWAN.

10 Tuberculous meningoencephalitis patients were recruited for this study with a mean age of 26 years ranging from 16 to 52 years-old. All images in the SWAN series were obtained using 8-channel phased array head coil on 3T clinical scanner (signa HDX machine, GE, Medical systems. Milwaukee, Wis, USA).the SWAN was a 3D gradient echo pulse sequence, and its parameters were: TR/TE=55.5/5.9 (ms), flip angle 20° bandwidth, 41.7Khz, section thickness, 2mm, matrix size, 416×256. the acquisition time was 5min 38 sec with the use of ASSET factor-2. After SWAN post-processing. 64 minIP slices of Magnitude and phase images of axial plane were generated. We evaluated granulomas and meningitis patterns in the flowing sequences: T2 weighted image; contrast enhanced T1weighted images; magnitude and phase images. Also CT scan was performed to determine whether a lesion on MRI images was a hyperdensity of calcification.

12 solitary nodules of ten patients had a hypointensity signal in Phase images. The active granulomas with contrast enhancement, depicts hypointense nodule related to the microvascular composition or the presence of paramagnetic substances. 6 patients with Tuberculous Leptomeningitis showed hypointense paramagnetism fills the cortical sulci in phase images and hyperintensity of the calcium deposition confirmed by CT scan.

The SWAN phase images is more sensitive in presenting the nodule characteristics of Tuberculous granulomas and leptomeningitis. Unlike calcified nodules, Granuloma and leptomeningitis containing paramagnetic substances or microvascular composition in the SWAN sequence showed hypointense patterns.

MRI SWAN can show the sensitive natures of the granuloma and meningitis tuberculosis transformation,non-calcified components in the SWAN showed hypointensity on the paramagnetic substance.

Lou, H, Wang, Q, Xu, S, MR T2 Star-weighted Angiography(SWAN) Findings of Granulomas and Leptomeningitis in Tuberculous Meningoencephalitis Patients.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11007780.html