Differentiation between fat-poor angiomyolipoma and clear cell renal cell carcinoma: qualitative and quantitative analysis using arterial spin labeling MR imaging

• Published in: Abdominal imaging 2020-02, Vol.45 (2), p.512-519
• Main Authors: Ye, Jing, Xu, Qing, Wang, Shou-An, Zheng, Jin, Zhu, Qing-Qiang, Dou, Wei-Qiang
• Format: Article
• Language: English
• Subjects: Angiomyolipoma; Angiomyolipoma - blood supply; Angiomyolipoma - diagnostic imaging; Bladder; Blood flow; Carcinoma, Renal Cell - blood supply; Carcinoma, Renal Cell - diagnostic imaging; Cell differentiation; Clear cell-type renal cell carcinoma; Diagnosis, Differential; Diagnostic systems; Female; Gastroenterology; Hepatology; Humans; Image Interpretation, Computer-Assisted; Image processing; Imaging; Informed consent; Kidney cancer; Kidney Neoplasms - blood supply; Kidney Neoplasms - diagnostic imaging; Kidneys; Labeling; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Mathematical analysis; Medical imaging; Medicine; Medicine & Public Health; Middle Aged; Neuroimaging; Perfusion; Prospective Studies; Qualitative analysis; Qualitative research; Quantitative analysis; Radiology; Renal cortex; Retroperitoneum; Spin labeling; Spin Labels; Surgery; Tumors; Ureters
• ISSN: 2366-004X; 2366-0058
• DOI: 10.1007/s00261-019-02303-w

Purpose To assess the diagnostic effectiveness of arterial spin labeling (ASL) MR imaging in differentiating fat-poor AML from clear cell renal cell carcinoma (ccRCC). Methods In this prospective study, 29 ccRCC patients and 9 fat-poor AML patients underwent routine anatomical MRI and ASL at 3T before surgery after signing written informed consent form. For each tumor, tumor blood flow (TBF) was measured in a region of interest (ROI) which was positioned to outline the edge of the target lesions on ASL perfusion maps. Additionally, the mean TBF values were obtained by standardizing the TBF using a blood flow measurement in the reference ROI. Moreover, a cluster containing more than 10 voxels was chosen from the renal cortex and medulla area in normal contralateral kidney as a reference ROI to calculate tumor-to-cortex ratio and tumor-to-medulla ratio. Independent sample t test was used to examine the alteration among the groups of fat-poor AML and ccRCC. ASL images were together analyzed by two radiologists to assess the following characteristics of the renal mass: predominant SI in the tumor on ASL images was lower than, as same as, or higher than SI of the cortex. For qualitative variables, Fisher’s exact test was employed to compare the proportions of these two groups. The sensitivity, specificity ,and accuracy required for discrimination of fat-poor AML from ccRCC were quantified using receiver operating characteristic (ROC) curve. The corresponding optimal cutoff value was obtained for each parameter as well. Results The TBF value was significantly higher in ccRCC group than that in fat-poor AML (270.49 ± 78.88 ml/100 g/min vs. 146.68 ± 47.21 ml/100 g/min; P