title: High resolution 3D diffusion cardiovascular magnetic resonance of carotid vessel wall to detect lipid core without contrast media.
abstract: BACKGROUND
  Without the need of contrast media, diffusion-weighted imaging (DWI) has shown great promise for accurate detection of lipid-rich necrotic core (LRNC), a well-known feature of vulnerable plaques. However, limited resolution and poor image quality in vivo with conventional single-shot diffusion-weighted echo planar imaging (SS-DWEPI) has hindered its clinical application. The aim of this work is to develop a diffusion-prepared turbo-spin-echo (DP-TSE) technique for carotid plaque characterization with 3D high resolution and improved image quality.
  
  
  METHODS
  Unlike SS-DWEPI where the diffusion encoding is integrated in the EPI framework, DP-TSE uses a diffusion encoding module separated from the TSE framework, allowing for segmented acquisition without the sensitivity to phase errors. The interleaved, motion-compensated sequence was designed to enable 3D black-blood DWI of carotid arteries with sub-millimeter resolution. The sequence was tested on 12 healthy subjects and compared with SS-DWEPI for image quality, vessel wall visibility, and vessel wall thickness measurements. A pilot study was performed on 6 patients with carotid plaques using this sequence and compared with conventional contrast-enhanced multi-contrast 2D TSE as the reference.
  
  
  RESULTS
  DP-TSE demonstrated advantages over SS-DWEPI for resolution and image quality. In the healthy subjects, vessel wall visibility was significantly higher with diffusion-prepared TSE (p < 0.001). Vessel wall thicknesses measured from diffusion-prepared TSE were on average 35% thinner than those from the EPI images due to less distortion and partial volume effect (p < 0.001). ADC measurements of healthy carotid vessel wall are 1.53 ± 0.23 × 10-3 mm2/s. In patients the mean ADC measurements in the LRNC area were significantly lower (0.60 ± 0.16 × 10-3 mm2/s) than those of the fibrous plaque tissue (1.27 ± 0.29 × 10-3 mm2/s, p < 0.01).
  
  
  CONCLUSIONS
  Diffusion-prepared CMR allows, for the first time, 3D DWI of the carotid arterial wall in vivo with high spatial resolution and improved image quality over SS-DWEPI. It can potentially detect LRNC without the use of contrast agents, allowing plaque characterization in patients with renal insufficiency.
authors.forename: Yibin
authors.initials: Y
authors.lastname: Xie
authors.forename: Wei
authors.initials: W
authors.lastname: Yu
authors.forename: Zhaoyang
authors.initials: Z
authors.lastname: Fan
authors.forename: Christopher
authors.initials: C
authors.lastname: Nguyen
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Bi
authors.forename: Jing
authors.initials: J
authors.lastname: An
authors.forename: Tianjing
authors.initials: T
authors.lastname: Zhang
authors.forename: Zhaoqi
authors.initials: Z
authors.lastname: Zhang
authors.forename: Debiao
authors.initials: D
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002339:Carotid Arteries / Q000737:chemistry / Q000473:pathology*; D002340:Carotid Artery Diseases / Q000175:diagnosis* / Q000473:pathology; D016022:Case-Control Studies; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008055:Lipids / Q000032:analysis*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D010865:Pilot Projects; D058226:Plaque, Atherosclerotic; D011237:Predictive Value of Tests
chemical_list: D003287:Contrast Media; D008055:Lipids