title: Susceptibility-weighted imaging in the evaluation of brain arteriovenous malformations.
abstract: BACKGROUND
  Digital subtraction angiography (DSA) remains the gold standard in the evaluation of arteriovenous malformations (AVMs). Susceptibility-weighted imaging (SWI), a relatively new magnetic resonance imaging (MRI) technique, exploits the magnetic susceptibility differences of various tissues, such as blood, iron and calcification. Earlier studies have shown that the magnitude and phase information of SWI offers improved sensitivity, revealing low-flow vascular malformations that are invisible on conventional gradient-echo (GRE) sequences.
  
  
  OBJECTIVE
  To evaluate the imaging appearance of AVMs on SWI.
  
  
  METHODS
  In this retrospective study, the appearance of the various components (feeding artery, nidus, and draining veins) of AVMs on the phase, magnitude, and minimal intensity projection (minIP) images of SWI were analyzed in 14 patients with AVM and compared with conventional sequences.
  
  
  RESULTS
  Detection and delineation of various components of AVMs was best achieved in the magnitude images. Although minIP was most effective in detecting hemorrhage and calcification, it was the magnitude image that could separate the hemorrhagic and calcified component in the nidus from the remaining nidus. The minIP was less effective in detecting the AVM components, especially nidus and draining vein, whereas conspicuity was poor with the phase images.
  
  
  CONCLUSIONS
  The magnitude images of the SWI help in differentiating the different components of AVM and also helps in differentiating nidus from hemorrhage and calcification.
authors.affiliation: Department of Imaging Sciences & Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum - 695 011, India.
authors.forename: Uttam
authors.initials: U
authors.lastname: George
authors.forename: Milan
authors.initials: M
authors.lastname: Jolappara
authors.forename: Chandrasekharan
authors.initials: C
authors.lastname: Kesavadas
authors.forename: Arun Kumar
authors.initials: AK
authors.lastname: Gupta
mesh_terms: D000293:Adolescent; D000328:Adult; D015901:Angiography, Digital Subtraction / Q000379:methods; D001165:Arteriovenous Malformations / Q000000981:diagnostic imaging* / Q000473:pathology*; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology*; D002648:Child; D004198:Disease Susceptibility; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult