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 (SI(IP), SI(OP)) 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. KEY POINTS: • Chemical shift MRI offers new information about fat within renal tumours. • Opposed-phase signal decrease can be observed in all renal cortical tumours. • A greater than 25 % decrease in signal appears to be diagnostic for clear cell RCCs.
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 (SI(IP), SI(OP)) 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. KEY POINTS: • Chemical shift MRI offers new information about fat within renal tumours. • Opposed-phase signal decrease can be observed in all renal cortical tumours. • A greater than 25 % decrease in signal appears to be diagnostic for clear cell RCCs.
Authors: D G Mitchell; I Kim; T S Chang; S Vinitski; P M Consigny; S A Saponaro; S M Ehrlich; M D Rifkin; R Rubin Journal: Invest Radiol Date: 1991-12 Impact factor: 6.016
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Authors: Shaheed W Hakim; Nicola Schieda; Taryn Hodgdon; Matthew D F McInnes; Marc Dilauro; Trevor A Flood Journal: Eur Radiol Date: 2015-06-03 Impact factor: 5.315
Authors: Andreas M Hötker; Yousef Mazaheri; Andreas Wibmer; Christoph A Karlo; Junting Zheng; Chaya S Moskowitz; Satish K Tickoo; Paul Russo; Hedvig Hricak; Oguz Akin Journal: AJR Am J Roentgenol Date: 2017-01-17 Impact factor: 3.959
Authors: Nicola Schieda; Matthew S Davenport; Ivan Pedrosa; Atul Shinagare; Hersch Chandarana; Nicole Curci; Ankur Doshi; Gary Israel; Erick Remer; Jane Wang; Stuart G Silverman Journal: J Magn Reson Imaging Date: 2019-01-28 Impact factor: 4.813