title: Respiratory self-gating for free-breathing magnetization transfer MRI of the abdomen.
abstract: OBJECTIVE
  Magnetization transfer (MT) MRI can be effective for the diagnosis of a broad range of fibrotic diseases, including liver fibrosis. However, respiratory motion, a major source of artifacts in thoracic and abdominal MR imaging, can obscure important anatomic structures, making diagnosis difficult. In this study, we explored the potential to combine free-breathing (FB) respiratory self-gating (RSG) methods with MT saturation for FB MT ratio (MTR) measurements of abdominal organs.
  
  
  METHODS
  A respiratory self-gated multiple-gradient recalled echo sequence with MT presaturation (RSG-MT GRE) was developed and applied in a series of seven normal volunteers. We compared the MTR values of liver, pancreas, kidney, spleen, and posterior paraspinal muscle measured using our RSG-MT GRE sequence and a conventional MT GRE sequence.
  
  
  RESULTS
  RSG consistently reduced motion artifacts within MT-weighted images acquired during FB, improved the accuracy of FB MTR measurements, and produced comparable MTRs to breath-holding MTR measurements.
  
  
  CONCLUSIONS
  RSG approaches may offer to improve the utility of MT-weighted imaging methods for the assessment of fibrotic diseases and tumor desmoplasia in abdominal organs.
authors: Department of Radiology, Northwestern University, Chicago, Illinois, USA.
authors: Weiguo
authors: W
authors: Li
authors: Department of Radiology, Northwestern University, Chicago, Illinois, USA.
authors: Zhuoli
authors: Z
authors: Zhang
authors: Department of Radiology, Northwestern University, Chicago, Illinois, USA.
authors: Kangan
authors: K
authors: Li
authors: Siemens Healthcare, Columbus, Ohio, USA.
authors: Ning
authors: N
authors: Jin
authors: Department of Radiology, Northwestern University, Chicago, Illinois, USA.
authors: Yue
authors: Y
authors: Zhang
authors: Department of Radiology, Northwestern University, Chicago, Illinois, USA.|Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, USA.
authors: Tianjing
authors: T
authors: Zhang
authors: Department of Radiology, Northwestern University, Chicago, Illinois, USA.
authors: Frank H
authors: FH
authors: Miller
authors: Department of Radiology, Northwestern University, Chicago, Illinois, USA.|Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, USA.
authors: Andrew C
authors: AC
authors: Larson
mesh_terms: D016477:Artifacts; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007668:Kidney / Q000033:anatomy & histology; D008099:Liver / Q000033:anatomy & histology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D018482:Muscle, Skeletal / Q000033:anatomy & histology; D010179:Pancreas / Q000033:anatomy & histology; D055425:Respiratory-Gated Imaging Techniques; D013154:Spleen / Q000033:anatomy & histology; D055815:Young Adult
keywords: abdomen; magnetization transfer; respiratory motion; respiratory self-gating