title: MRI for differentiation of renal cell carcinoma with sarcomatoid component from other renal tumor types.
abstract: OBJECTIVE
  To investigate the usefulness of MRI for detection of sarcomatoid renal cell carcinoma (SRCC) components within RCC and differentiation from other renal tumors.
  
  
  METHODS
  Two observers independently interpreted T2-weighted images of 10 patients with pathologically confirmed RCCs with SRCC and 131 with non-SRCC renal tumors, with special reference to conspicuously low signal intensity (SI) areas (T2LIA) compared to the renal cortex. SRCC probability was classified as (1) definitely non-SRCC, no T2LIA; (2) probably non-SRCC, <1 cm T2LIA; (3) low probability of SRCC, homogeneous tumor with 1-3 cm T2LIA; (4) probably SRCC, heterogeneous tumor with 1-3 cm T2LIA; and (5) definitely SRCC, >3 cm T2LIA, multiple >1 cm T2LIAs, or showing disruption of the pseudocapsule. The observers used chemical shift imaging to exclude the area representing hemorrhage or hemosiderin deposition from T2LIA. Scores of 4/5 were regarded as positive for evaluating the accuracy and area under the receiver operating characteristic curve. The SI ratio of the lowest SI in the tumor to that of the renal cortex in the 1 and ≥2 score groups was compared using Mann-Whitney's U test.
  
  
  RESULTS
  Sensitivity, specificity, accuracy, and positive and negative predictive values were 90%, 95%, 94%, 56%, and 99%, respectively, and area under the receiver operating characteristic curve was 0.93. The mean SI ratio of the lowest SI in the tumor to that of the renal cortex was significantly lower in the ≥2 score group (0.58) than in the 1 score group (1.36).
  
  
  CONCLUSIONS
  MRI predicted RCC with SRCC with a moderate positive predictive value and a high negative predictive value.
authors: Department of Radiology, Nagoya City University Graduate School of Medical Sciences and Medical school, 1 Kawasumi Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan, m2rbimn@gmail.com.
authors: Mitsuru
authors: M
authors: Takeuchi
authors: Tatsuya
authors: T
authors: Kawai
authors: Tomohiro
authors: T
authors: Suzuki
authors: Taku
authors: T
authors: Naiki
authors: Noriyasu
authors: N
authors: Kawai
authors: Yukio
authors: Y
authors: Fujiyoshi
authors: Hiroshi
authors: H
authors: Inagaki
authors: Kenjiro
authors: K
authors: Kohri
authors: Masaki
authors: M
authors: Hara
authors: Yuta
authors: Y
authors: Shibamoto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007668:Kidney / Q000473:pathology; D007680:Kidney Neoplasms / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D012372:ROC Curve; D012680:Sensitivity and Specificity; D055815:Young Adult