01-05-2014 | Urogenital
Routinely performed multiparametric magnetic resonance imaging helps to differentiate common subtypes of renal tumours
Published in: European Radiology | Issue 5/2014
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Objectives
To retrospectively evaluate the ability of multiparametric magnetic resonance (MR) imaging to differentiate renal tumours.
Methods
MR images from 100 consecutive pathologically proven solid renal tumours without macroscopic fat [57 clear cell, 16 papillary and 7 chromophobe renal cell carcinomas (RCCs), 16 oncocytomas and 4 minimal fat angiomyolipomas (AMLs)] between 2009 and 2012 were evaluated. Two radiologists blinded to pathology results independently reviewed double-echo chemical shift, dynamic contrast-enhanced T1- and T2-weighted images and apparent diffusion coefficient (ADC) maps. Signal intensity index (SII), tumour-to-spleen SI ratio (TSR), ADC ratio, wash-in (WiI) and wash-out indices (WoI) between different phases were calculated.
Results
There were significant differences between papillary RCCs and other renal tumours for arterial WiI (P < 0.001), initial WoI (P = 0.006) and ADC ratio (P < 0.001); between chromophobe RCCs and oncocytomas for TSR (P = 0.02), parenchymal WiI (P = 0.03), late WiI (P = 0.02), initial WoI (P = 0.03) and late WoI (P = 0.04); and between clear cell RCCs and oncocytomas for SII (P = 0.01) and parenchymal WiI (P = 0.01). Papillary RCCs were distinguished from other tumours (sensitivity 37.5 %, specificity 100 %) and oncocytomas from chromophobe RCCs (sensitivity 25 %, specificity 100 %) and clear cell RCCs (sensitivity 100 %, specificity 94.2 %).
Conclusion
MR imaging provides criteria able to accurately distinguish papillary RCCs from other tumours and oncocytomas from chromophobe and clear cell RCCs.
Key Points
• Multiparametric MR parameters accurately distinguish papillary RCCs with high specificity (100 %).
• Oncocytomas can be distinguished from chromophobe RCCs with high specificity (100 %).
• Oncocytomas can be distinguished from clear cell RCCs with high specificity (94.2 %).
• In oncocytomatosis, imaging follow-up with such parameters analysis could be promoted.