title: Comprehensive small animal imaging strategies on a clinical 3 T dedicated head MR-scanner; adapted methods and sequence protocols in CNS pathologies.
abstract: BACKGROUND
  Small animal models of human diseases are an indispensable aspect of pre-clinical research. Being dynamic, most pathologies demand extensive longitudinal monitoring to understand disease mechanisms, drug efficacy and side effects. These considerations often demand the concomitant development of monitoring systems with sufficient temporal and spatial resolution.
  
  
  RESULTS
  This study attempts to configure and optimize a clinical 3 Tesla magnetic resonance scanner to facilitate imaging of small animal central nervous system pathologies. The hardware of the scanner was complemented by a custom-built, 4-channel phased array coil system. Extensive modification of standard sequence protocols was carried out based on tissue relaxometric calculations. Proton density differences between the gray and white matter of the rodent spinal cord along with transverse relaxation due to magnetic susceptibility differences at the cortex and striatum of both rats and mice demonstrated statistically significant differences. The employed parallel imaging reconstruction algorithms had distinct properties dependent on the sequence type and in the presence of the contrast agent. The attempt to morphologically phenotype a normal healthy rat brain in multiple planes delineated a number of anatomical regions, and all the clinically relevant sequels following acute cerebral ischemia could be adequately characterized. Changes in blood-brain-barrier permeability following ischemia-reperfusion were also apparent at a later time. Typical characteristics of intra-cerebral haemorrhage at acute and chronic stages were also visualized up to one month. Two models of rodent spinal cord injury were adequately characterized and closely mimicked the results of histological studies. In the employed rodent animal handling system a mouse model of glioblastoma was also studied with unequivocal results.
  
  
  CONCLUSIONS
  The implemented customizations including extensive sequence protocol modifications resulted in images of high diagnostic quality. These results prove that lack of dedicated animal scanners shouldn't discourage conventional small animal imaging studies.
authors.affiliation: Department of Neurology, Regensburg University Medical Centre, Regensburg, Germany.
authors.forename: Deepu R
authors.initials: DR
authors.lastname: Pillai
authors.forename: Robin M
authors.initials: RM
authors.lastname: Heidemann
authors.forename: Praveen
authors.initials: P
authors.lastname: Kumar
authors.forename: Nagesh
authors.initials: N
authors.lastname: Shanbhag
authors.forename: Titus
authors.initials: T
authors.lastname: Lanz
authors.forename: Michael S
authors.initials: MS
authors.lastname: Dittmar
authors.forename: Beatrice
authors.initials: B
authors.lastname: Sandner
authors.forename: Christoph P
authors.initials: CP
authors.lastname: Beier
authors.forename: Norbert
authors.initials: N
authors.lastname: Weidner
authors.forename: Mark W
authors.initials: MW
authors.lastname: Greenlee
authors.forename: Gerhard
authors.initials: G
authors.lastname: Schuierer
authors.forename: Ulrich
authors.initials: U
authors.lastname: Bogdahn
authors.forename: Felix
authors.initials: F
authors.lastname: Schlachetzki
mesh_terms: D000818:Animals; D049628:Body Size / Q000502:physiology; D002138:Calibration; D002493:Central Nervous System Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D004195:Disease Models, Animal; D006257:Head / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods* / Q000592:standards / Q000662:veterinary; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D011859:Radiography; D051381:Rats; D017208:Rats, Wistar; D012377:Rodentia; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured