Re: Xu et al.: “Renal cell carcinoma: real-time contrast-enhanced ultrasound findings”

Renal oncocytoma: contrast-enhanced sonographic features

OBJECTIVES

The purpose of this study was to illustrate the features of renal oncocytoma on contrast-enhanced sonography.

METHODS

Five cases of surgical pathologically proven renal oncocytoma were retrospectively reviewed and analyzed in this study. The 5 patients studied included 3 men and 2 women with a mean age of 52.3 years (range, 32-66 years). All patients underwent conventional and contrast-enhanced sonographic examinations before surgery. The sonographic features, enhancement pattern, and dynamic perfusion change of the tumors and renal parenchyma in vascular phases were evaluated and compared to computed tomography.

RESULTS

On grayscale sonography, renal oncocytomas appeared as solitary hypoechoic or isoechoic masses originating from the renal cortex measuring 2 to 6 cm with a well-defined margin. Color Doppler flow imaging showed rich blood flow signals in the periphery and striplike blood flow signals within the masses. On contrast-enhanced sonography, the features of these tumors included early enhancement, hyperenhancement, and fast wash-out compared to the adjacent renal cortex. There were irregular nonenhanced areas seen in the center of the masses (n = 3) and nonenhanced thin rims seen in the periphery (n = 5). Macroscopically, the well-marginated tumors were yellowish brown with a tender texture and were located in the renal cortex. Central irregularly shaped fibrous scars were seen in 3 tumors, consistent with nonenhanced areas on contrast-enhanced imaging.

CONCLUSIONS

Contrast-enhanced sonography can provide valuable hemodynamic information on renal oncocytoma, which may help in making a differential diagnosis of this benign renal tumor in clinical practice.

Improved outcome of percutaneous radiofrequency ablation in renal cell carcinoma: a retrospective study of intraoperative contrast-enhanced ultrasonography in 73 patients

OBJECTIVES

To evaluate the impact of contrast-enhanced ultrasonography (CEUS) during percutaneous radiofrequency ablation (PRFA) procedure in renal cell carcinoma (RCC).

METHODS

From January 2008 to July 2010, 73 patients with sporadic unilateral RCC were enrolled to our study (57 men and 16 women, age range: 37-78 years, mean age 57.9 years). The diameter of the tumor was 1.7-5.8, 3.4 cm on average. The patients were divided into two groups depending on the intraoperative ultrasonography type: CEUS group and conventional ultrasound group. Patients in CEUS group received CEUS before insertion of the electrode, and the second CEUS was performed right after the initial ablation to dynamically evaluate the images. If there was highly suspicious residue, additional ablation and repeated CEUS were applied. Patients in the conventional ultrasound group received PRFA guided by gray-scale ultrasound. All of these patients received contrast-enhanced computed tomography (CT) examination 7 days after the procedure (patients in CEUS group received CEUS conducted with each CT scan), with subsequent CT and CEUS assessment at 3, 6, and every 6 months thereafter.

RESULTS

The mean follow-up period was 22 months (range: 12-42 months). All tumors were biopsied before RFA. The local tumor control rate was 94.6% (35/37) in the CEUS group and 86.1% (31/36) in the conventional ultrasound group (P < 0.05); the cancer-specific survival rate and the overall survival rate were 100%. The post-RFA (12 months) mean GFR levels were 84.7 ± 27.5 mL/min/1.73 m(2) (P > 0.05, compared with pre-GFR: 86.4 ± 26.2 mL/min/1.73 m(2)) in the CEUS group and 81.9 ± 22.8 mL/min/1.73 m(2) (P > 0.05, compared with pre-GFR: 83.5 ± 23.7 mL/min/1.73 m(2)) in the conventional ultrasound group.

CONCLUSION

Intraoperative CEUS can "real-time" monitor the ablated area during PRFA procedure. This technique can help to achieve a higher success rate compared with conventional ultrasound. No impact of intraoperative CEUS has been found on GFR level.

Contrast-enhanced ultrasound in abdominal imaging

The administration of a contrast agent is considered an essential tool to evaluate abdominal diseases using Ultrasound. The most targeted organ is the liver, especially to characterize focal liver lesions and to assess the response to percutaneous treatment. However, the expanding abdominal indications of contrast-enhanced ultrasound make this technique an important tool in the assessment of organ perfusion including the evaluation of ischemic, traumatic, and inflammatory diseases.

Short-term evaluation of liver tumors after transarterial chemoembolization: limitations and feasibility of contrast-enhanced ultrasonography

PURPOSE

To evaluate the limitations and the feasibility of contrast-enhanced ultrasonography (CEUS) for the assessment of tumor response shortly after transarterial chemoembolization (TACE).

MATERIALS AND METHODS

Fifty seven patients (41 patients with hepatomas, 16 patients with metastases) were studied with CEUS before, 1 day after, and 30 days after TACE. A CEUS-efficiency score (CEUS-ES) was calculated, which evaluated: (a) the completeness of visualization of the target tumor(s) (2: good, 1: adequate, 0: poor) and (b) the quality of delineation of post-TACE necroses (2: good, 1: adequate, 0: poor). A CEUS study was considered as "diagnostic," if each of the aforementioned parameters was associated with grade 1 or 2.

RESULTS

CEUS studies were "diagnostic" in 36/57 patients (63.1%). Patients with hepatomas were more likely to undergo "diagnostic" CEUS than patients with metastases (70.7% vs. 43.7%, P = 0.0728). Lesions' multiplicity, deep location, hypoenhancement on pretreatment CEUS, and diffuse growth had a statistically significant (P < 0.05) negative impact on CEUS-ES. Hyperechogenicity on pre-treatment, unenhanced US had a non-statistically significant (P = 0.176) negative impact. Differences between "diagnostic" CEUS studies and CT/MR regarding detection of residual tumor were insignificant (P = 0.8178).

CONCLUSION

The percentage of lesions which are unsuitable for post-TACE evaluation with CEUS is not negligible. For the rest, the respective role of CEUS is promising.