title: Small solid renal masses: characterization by diffusion-weighted MRI at 3 T.
abstract: OBJECTIVE
  To describe the appearance of small solid renal lesions (≤3 cm) on diffusion-weighted magnetic resonance imaging (MRI) and to determine whether ADC measurements may help to differentiate benign from malignant small solid renal masses.
  
  
  METHODS
  Thirty-five patients with 47 small renal masses (23 malignant, 24 benign) who underwent 3 T MRI of the kidney using diffusion-weighted sequences (b values of 0 and 1000 s/mm(2)) were retrospectively evaluated. Qualitative and quantitative analysis of diffusion-weighted images was performed.
  
  
  RESULTS
  Most lesions were hyperintense to kidney on high b-value diffusion-weighted images and hypointense on apparent diffusion coefficient (ADC) map. The mean ADC of the lesions was significantly lower than that of kidney (1.22 ± 0.3 versus 1.85 ± 0.12 mm(2)/s; p < 0.005). The mean ADC was significantly different between renal cell carcinomas (1.2 ± 0.01 mm(2)/s), metastases (1.25 ± 0.04 mm(2)/s), angiomyolipoma (1.07 ± 0.3 mm(2)/s) and oncocytomas (1.56 ± 0.08 mm(2)/s; p < 0.05). The mean ADC of clear cell renal cell carcinomas was significantly different from that of non-clear cell renal cell carcinomas (1.38 ± 0.34 versus 0.83 ± 0.34 mm(2)/s; p < 0.005). No significant difference was found between mean ADC of fat containing and minimal fat angiomyolipomas (1.06 ± 0.48 versus 1.11 ± 0.33 mm(2)/s).
  
  
  CONCLUSIONS
  Small solid renal masses are hyperintense on high b value and have different ADC values.
authors: Department of Radiology B, Universitary Hospital of Strasbourg, Strasbourg, France. fra.agnello@libero.it
authors: F
authors: F
authors: Agnello
authors: C
authors: C
authors: Roy
authors: G
authors: G
authors: Bazille
authors: M
authors: M
authors: Galia
authors: M
authors: M
authors: Midiri
authors: T
authors: T
authors: Charles
authors: H
authors: H
authors: Lang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007668:Kidney / Q000473:pathology; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008875:Middle Aged