title: Evaluation of a Gadolinium-Based Nanoparticle (AGuIX) for Contrast-Enhanced MRI of the Liver in a Rat Model of Hepatic Colorectal Cancer Metastases at 9.4 Tesla.
abstract: OBJECTIVE
  The aim of this study was to compare a Gd-based nanoparticle (AGuIX) with a standard extracellular Gd-based contrast agent (Gd-DOTA) for MRI at 9.4 T in rats with hepatic colorectal cancer metastases.
  
  
  METHODS
  12 rats with hepatic metastases were subjected to MRI using a 9.4 T animal scanner. T1w self-gated FLASH sequences (TR/TE = 45/2.5 ms, alpha = 45°, TA = 1: 23 min, FOV = 5.12 × 5.12 cm(2), matrix = 256 × 256) were acquired before and at 10 time points after contrast injection. Each animal received 0.1 mmol/kg BW Gd-DOTA i.v. 2 days later AGuIX was applied at 0.01 mmol/kg BW (representing equal Gd doses). The SNR of normal liver (SNRliver), hyper- and hypoenhancing parts of tumors (SNRtumor, hyperenh/SNRtumor, hypoenhanc), erector spinae muscle (SNRmuscle), CNR and lesion enhancement (LE) were calculated based on ROI measurements.
  
  
  RESULTS
  Mean SNRliver (Gd-DOTA: 14.6 +/- 0.7; AGuIX: 28.2+/- 2.6, p < 0.001), SNRtumor, hyperenhanc (Gd-DOTA: 18.6 +/- 1.2; AGuIX: 29.6 +/- 2.8, p < 0.001), SNRtumor, hypoenhanc (Gd-DOTA: 12.0 +/- 0.7; AGuIX: 15.4 +/- 0.7, p < 0.001), SNRmuscle (Gd-DOTA: 12.3 +/- 0.3; AGuIX: 14.0 +/- 0.7, p < 0.001), mean CNR (Gd-DOTA: -2.5 +/- 0.2; AGuIX: -7.5 +/- 1.0, p < 0.001) and LE (Gd-DOTA: 3.8 +/- 0.7; AGuIX: 14.9 +/- 2.8, p = 0.001) were significantly higher using AGuIX. Regardless of the larger molecular size, AGuIX demonstrates an early peak enhancement followed by a continuous washout.
  
  
  CONCLUSIONS
  AGuIX provides better enhancement at 9.4 T compared to Gd-DOTA for equal doses of applied Gd. This is based on the molecule structure and the subsequent increased interaction with protons leading to a higher relaxivity. AGuIX potentially ameliorates the conspicuity of focal liver lesions and may improve the sensitivity in diagnostic imaging of malignant hepatic tumors.
  
  
  CONCLUSIONS
  AGuIX provides superior enhancement as compared to the extracellular compound Gd-DOTA at 9.4 T. AGuIX may improve the detection and diagnostic sensitivity of malignant focal liver lesions. The small size of AGuIX allows for fast renal clearance and prevents undesirable accumulation in the body.
authors.affiliation: Clinic of Diagnostic and Interventional Radiology, Saarland University Medical Center, Homburg, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Fries
authors.affiliation: Clinic of Diagnostic and Interventional Radiology, Saarland University Medical Center, Homburg, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Morr
authors.affiliation: Clinic of Diagnostic and Interventional Radiology, Saarland University Medical Center, Homburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Müller
authors.affiliation: Laboratoire de Physico-Chimie des Matériaux Luminescents, Université Claude Bernard, Lyon, France.
authors.forename: F
authors.initials: F
authors.lastname: Lux
authors.affiliation: Laboratoire de Physico-Chimie des Matériaux Luminescents, Université Claude Bernard, Lyon, France.
authors.forename: O
authors.initials: O
authors.lastname: Tillement
authors.affiliation: Clinic of Diagnostic and Interventional Radiology, Saarland University Medical Center, Homburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Massmann
authors.affiliation: Clinic of Diagnostic and Interventional Radiology, Saarland University Medical Center, Homburg, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Seidel
authors.affiliation: Department of General, Visceral and Pediatric Surgery, Saarland University Medical Center, Homburg, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Schäfer
authors.affiliation: Institute for Clinical and Experimental Surgery, Saarland University Medical Center, Homburg, Germany.
authors.forename: M D
authors.initials: MD
authors.lastname: Menger
authors.affiliation: Clinic of Diagnostic and Interventional Radiology, Saarland University Medical Center, Homburg, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Schneider
authors.affiliation: Clinic of Diagnostic and Interventional Radiology, Saarland University Medical Center, Homburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Bücker
mesh_terms: D000818:Animals; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000473:pathology; D003287:Contrast Media; D005260:Female; D006571:Heterocyclic Compounds / Q000737:chemistry; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000175:diagnosis* / Q000556:secondary*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry; D009368:Neoplasm Transplantation; D009942:Organometallic Compounds / Q000737:chemistry; D011856:Radiographic Image Enhancement / Q000379:methods*; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D012833:Siloxanes / Q000737:chemistry
chemical_list: D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; D012833:Siloxanes; C050823:gadolinium 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetate