Dynamic MRI of small renal cell carcinoma.

OBJECTIVE

To evaluate the appearance of contrast-enhanced dynamic MRI of small renal cell carcinoma (RCC) (< 3 cm diameter).

MATERIALS AND METHODS

Twenty-seven patients with 28 small RCCs were studied by both conventional spin echo and contrast-enhanced dynamic MRI for tumor detection and characterization. All tumors were detected by contrast-enhanced CT and confirmed by operation. Dynamic MRI was performed using a breath-hold fast low angle shot technique after rapid injection of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA). Characterization of a renal mass was done by the visual analysis of tumor vascularity as well as quantitative assessment of the contrast noise ratio (CNR) and degree of enhancement.

RESULTS

With conventional spin echo MR and dynamic MR, 18 and 26 of 28 small RCCs were detected, respectively. In the dynamic study the tumor/renal medulla contrast was marked at 90-120 s after administration of Gd-DTPA (CNR:15.1). The tumor/renal medulla contrast in the dynamic study was more marked than that of postcontrast T1-weighted imaging (CNR, -0.25); T2-weighted imaging (CNR, 3.1); and T1-weighted imaging (CNR, -0.76).

CONCLUSION

Contrast-enhanced dynamic MRI is a useful technique for the diagnosis of small RCC especially in a patient with renal insufficiency or allergy to iodinated contrast material.