title: High-resolution 3 T MR microscopy imaging of arterial walls.
abstract: OBJECTIVE
  To achieve a high spatial resolution in MR imaging that allows for clear visualization of anatomy and even histology and documentation of plaque morphology in in vitro samples from patients with advanced atherosclerosis. A further objective of our study was to evaluate whether T2-weighted high-resolution MR imaging can provide accurate classification of atherosclerotic plaque according to a modified American Heart Association classification.
  
  
  METHODS
  T2-weighted images of arteries were obtained in 13 in vitro specimens using a 3 T MR unit (Medspec 300 Avance/Bruker, Ettlingen, Germany) combined with a dedicated MR microscopy system. Measurement parameters were: T2-weighted sequences with TR 3.5 sec, TE 15-120 msec; field of view (FOV) 1.4 x 1.4; NEX 8; matrix 192; and slice thickness 600 microm. MR measurements were compared with corresponding histologic sections.
  
  
  RESULTS
  We achieved excellent spatial and contrast resolution in all specimens. We found high agreement between MR images and histology with regard to the morphology and extent of intimal proliferations in all but 2 specimens. We could differentiate fibrous caps and calcifications from lipid plaque components based on differences in signal intensity in order to differentiate hard and soft atheromatous plaques. Hard plaques with predominantly intimal calcifications were found in 7 specimens, and soft plaques with a cholesterol/lipid content in 5 cases. In all specimens, hemorrhage or thrombus formation, and fibrotic and hyalinized tissue could be detected on both MR imaging and histopathology.
  
  
  CONCLUSIONS
  High-resolution, high-field MR imaging of arterial walls demonstrates the morphologic features, volume, and extent of intimal proliferations with high spatial and contrast resolution in in vitro specimens and can differentiate hard and soft plaques.
authors.affiliation: Department of Angiography and Interventional Radiology, University of Vienna, Vienna, Austria. johannes.sailer@univie.ac.at
authors.forename: Johannes
authors.initials: J
authors.lastname: Sailer
authors.forename: Thomas
authors.initials: T
authors.lastname: Rand
authors.forename: Andreas
authors.initials: A
authors.lastname: Berg
authors.forename: Irene
authors.initials: I
authors.lastname: Sulzbacher
authors.forename: P
authors.initials: P
authors.lastname: Peloschek
authors.forename: Thomas
authors.initials: T
authors.lastname: Hölzenbein
authors.forename: Johannes
authors.initials: J
authors.lastname: Lammer
mesh_terms: D000368:Aged; D001158:Arteries / Q000473:pathology*; D050197:Atherosclerosis / Q000473:pathology*; D005260:Female; D006801:Humans; D007089:Image Enhancement; D066298:In Vitro Techniques; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods; D008297:Male; D008853:Microscopy; D015588:Observer Variation; D012680:Sensitivity and Specificity