OBJECTIVES: To assess qualitative and quantitative chemical shift MRI parameters of renal cortical tumours.
METHODS: A total of 251 consecutive patients underwent 1.5-T MRI before nephrectomy. Two readers (R1, R2) independently evaluated all tumours visually for a decrease in signal intensity (SI) on opposed- compared with in-phase chemical shift images. In addition, SI was measured on in- and opposed-phase images (SIIP, SIOP) and the chemical shift index was calculated as a measure of percentage SI change. Histopathology served as the standard of reference.
RESULTS: A visual decrease in SI was identified significantly more often in clear cell renal cell carcinoma (RCCs) (R1, 73 %; R2, 64 %) and angiomyolipomas (both, 80 %) than in oncocytomas (29 %, 12 %), papillary (29 %, 17 %) and chromophobe RCCs (13 %, 9 %; all, P < 0.05). Median chemical shift index was significantly greater in clear cell RCC and angiomyolipoma than in the other histological subtypes (both, P < 0.001). Interobserver agreement was fair for visual (kappa, 0.4) and excellent for quantitative analysis (concordance correlation coefficient, 0.80).
CONCLUSIONS: A decrease in SI on opposed-phase chemical shift images is not an identifying feature of clear cell RCCs or angiomyolipomas, but can also be observed in oncocytomas, papillary and chromophobe RCCs. After excluding angiomyolipomas, a decrease in SI of more than 25 % was diagnostic for clear cell RCCs.
Written by:
Karlo CA, Donati OF, Burger IA, Zheng J, Moskowitz CS, Hricak H, Akin O. Are you the author?
Department of Radiology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue. Radiology Academic Offices, Room C278, New York, NY, 10065, USA.
Reference: Eur Radiol. 2013 Jan 10. Epub ahead of print.
doi: 10.1007/s00330-012-2758-x
PubMed Abstract
PMID: 23300041
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