Korean J Urol.  2014 Sep;55(9):587-592. 10.4111/kju.2014.55.9.587.

Diagnostic Efficacy of Contrast-Enhanced Ultrasound for Small Renal Masses

• Oh TH
• Lee YH
• Seo IY

• KMID: 2069776
• DOI: http://doi.org/10.4111/kju.2014.55.9.587

Abstract

PURPOSE
Ultrasound (US) is highly sensitive in the detection of renal masses. However, it may not be able to differentiate benign and malignant lesions in smaller masses. The purpose of this study was to determine the diagnostic efficacy of contrast-enhanced ultrasound (CEUS) for small renal masses.
MATERIALS AND METHODS
From January 2011 to December 2013, a total of 85 patients underwent CEUS for evaluation of renal masses. Of these patients, CEUS findings were retrospectively analyzed for small renal cell carcinoma (RCC) cases (n=38) and angiomyolipoma (AML) cases (n=11). The tumor echogenicity and enhancement patterns and degrees were evaluated. The diagnostic efficacy of CEUS in differentiating the two diseases was compared.
RESULTS
On CEUS, the findings of diffuse heterogeneous enhancement (observed in 78.9% of RCCs and 27.3% of AMLs, p=0.003), washout from hyperenhancement or iso-enhancement to hypoenhancement in late phase (73.7% of RCCs and 18.2% of AMLs, p=0.001), and perilesional rim-like enhancement (57.9% of RCCs and 9.1% of AMLs, p=0.006) were significantly different between AML and RCC cases. The corresponding sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 86.8% (33/38), 63.6% (7/11), 89.2% (33/37), 58.3% (7/12), and 81.6% (40/49), respectively.
CONCLUSIONS
Our results suggest that the characteristic CEUS features could have diagnostic value in the evaluation of small renal mass. CEUS showed a higher diagnostic efficacy than conventional US for differentiating RCC and AML.

Keyword

Angiomyolipoma; Contrast media; Renal cell carcinoma; Ultrasonography

MeSH Terms

Adult
Aged
Aged, 80 and over
Angiomyolipoma/*ultrasonography
Carcinoma, Renal Cell/*ultrasonography
Contrast Media/diagnostic use
Diagnosis, Differential
Female
Humans
Kidney Neoplasms/*ultrasonography
Male
Middle Aged
Reproducibility of Results
Retrospective Studies
Sensitivity and Specificity
Sulfur Hexafluoride/diagnostic use
Ultrasonography/*methods
Contrast Media
Sulfur Hexafluoride

Figure

• 

  FIG. 1 A 42-year-old man with clear cell renal carcinoma. (A) Conventional ultrasonography demonstrated that a hypoechogenic mass with a diameter of 2.8 cm was located in the left lower kidney. (B) Contrast-enhanced ultrasound (CEUS) imaging of the arterial phase showed a diffuse, heterogeneous enhanced tumor. (C) CEUS imaging at the late phase showed washout of the tumor. (D) CEUS imaging at the late phase showed perilesional enhancement with slow centripetal fill in a rim-like pattern.

• 

  FIG. 2 A 56-year-old man with angiomyolipoma. (A) Conventional ultrasonography demonstrated that a hyperechogenic mass with a diameter of 2.3 cm was located in the left lower kidney. (B) Contrast-enhanced ultrasound imaging in the late phase showed a dot-like enhancement.

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