title: USPIO-enhanced MR imaging of macrophage infiltration in native and transplanted kidneys: initial results in humans.
abstract: The purpose of this study was to evaluate the detection and characterization of macrophage infiltration in native and transplanted kidneys using ultrasmall superparamagnetic iron oxide particles (USPIO). Among 21 patients initially enrolled, 12 scheduled for renal biopsy for acute or rapidly progressive renal failure (n = 7) or renal graft rejection (n = 5) completed the study. Three magnetic resonance (MR) sessions were performed with a 1.5-T system, before, immediately after and 72 h after i.v. injection of USPIO at doses of 1.7-2.6 mg of iron/kg. Signal intensity change was evaluated visually and calculated based on a region of interest (ROI) positioned on the kidney compartments. Histological examination showed cortical macrophage infiltration in four patients (>5 macrophages/mm(2)), two in native kidneys (proliferative extracapillary glomerulonephritis) and two in transplants (acute rejection). These patients showed a 33 +/- 18% mean cortical signal loss on T2*-weighted images. In the remaining eight patients, with <5 macrophages/mm(2), there was no cortical signal loss. However, in three of these, presenting with ischemic acute tubular necrosis, a strong (42 +/- 18%) signal drop was found in the medulla exclusively. USPIO-enhanced MR imaging can demonstrate infiltration of the kidneys by macrophages both in native and transplanted kidneys and may help to differentiate between kidney diseases.
authors.affiliation: Service d'Imagerie Diagnostique et Thérapeutique de l'Adulte, Groupe Hospitalier Pellegrin, Place Amélie Raba-Léon, 33076, Bordeaux Cedex, France. olivier.hauger@chu-bordeaux.fr
authors.forename: Olivier
authors.initials: O
authors.lastname: Hauger
authors.forename: Nicolas
authors.initials: N
authors.lastname: Grenier
authors.forename: Colette
authors.initials: C
authors.lastname: Deminère
authors.forename: Catherine
authors.initials: C
authors.lastname: Lasseur
authors.forename: Yahsou
authors.initials: Y
authors.lastname: Delmas
authors.forename: Pierre
authors.initials: P
authors.lastname: Merville
authors.forename: Christian
authors.initials: C
authors.lastname: Combe
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000494:pharmacology; D005260:Female; D005290:Ferric Compounds / Q000737:chemistry; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007668:Kidney / Q000378:metabolism / Q000473:pathology; D016030:Kidney Transplantation / Q000379:methods*; D008262:Macrophage Activation; D008264:Macrophages / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; C000499:ferric oxide