**13. Cystic renal lesions**

**12. Metastases and lymphoma**

(Section 22).

128 Evolving Trends in Kidney Cancer

morphometric pattern.

Imaging features suggestive for metastasis or lymphoma are: size <3 cm, lack of spherical shape, "infiltrative" growth, multiplicity, and bilaterality. There are no capsules or calcifications [8].

**Figure 10.** Oncocytoma. Round, parenchymal mass with enhancement of the peripheral vascular bed in the arterial time

**Figure 11.** Renal lymphoma. CEUS evaluation (left) with an area of hypoenhancement at the upper pole; gray scale evaluation (right) with no signs of tumor. Vascular evaluation seems to be superior for the diagnostic than the At imaging studies, approximately 10% of kidney cancers have a complex cystic appearance. Nonmalignant renal tumors may also have a complex appearance. This is most commonly due to the hemorrhage, infection, inflammation or ischemia. Differentiation between complex cysts requiring surgical treatment or monitoring is essential. The identification of vascularity in the solid area or septa of cystic lesions by CEUS simplifies the diagnosis of lesions with high malignancy potential [24].

The Bosniak classification differentiates five categories of renal cysts named I, II, IIf, III, and IV based on the imaging criteria (ultrasound and CT), being used for further clinical management of the patient [8, 25].

First Bosniak category, called I, depicts thin walls of the cyst, without septa and sharp margins. There are no solid components or calcifications. No enhancement is depicted on CEUS. There is no malignancy potential (**Figure 12**) [8, 25].

**Figure 12.** (a and b) Renal cyst. CEUS evaluation (a); an gray scale evaluation (b). In CEUS (asterisc), the lack of vascular signal suggests an avascular lesion compatible with the diagnosis of cyst.

Renal cysts from second category, II, are characterized by septa thinner than 1 mm, which might have fine calcifications. No contrast enhancement or very discrete enhancement is observed. The malignant potential is 0% [8, 25].

Another future application is related to robotic-assisted partial nephrectomy, which has gained prominence recently, as this approach has a shorter learning curve and a shorter warm ischemia time as compared to laparoscopic partial nephrectomy [32]. CEUS is capable of dynamic evaluation and quantification of microvasculature blood (capillary perfusion) in real time, without affecting renal function. When used in conjunction with a robotic ultrasound probe, CEUS can facilitate better visualization of renal vasculature and tumor and ultimately improving acumen and precision. CEUS is a valuable and a cost-effective tool for the identification of renal blood flow in robotic-assisted partial nephrectomy, especially with complex, challenging tumors [32].

Harmonic Contrast-Enhanced Ultrasound (CEUS) of Kidney Tumors

http://dx.doi.org/10.5772/intechopen.77376

131

The CEUS examination is an important progress for ultrasonography. The procedure depicts dynamic angio-perfusion. It is valuable in strengthening the diagnosis of renal cancer by evidencing neo-angiogenesis. It is useful in detecting tumor and nontumor circulatory abnormalities.

This work was supported by a grant of the Romanian Ministry of Research and Innovation, CCDI-UEFISCDI, project number PN-III-P1-1.2-PCCDI-2017-0056/3, within PNCDI III.

Lidia Ciobanu\*, Attila Tamas Szora, Alexandru Florin Badea, Mihai Suciu and Radu Badea

[1] Badea R, Ciobanu L.Contrast enhanced and Doppler ultrasonography in the characterization of the microcirculation. Expectancies and performances. Medical Ultrasonography.

[2] Cosgrove D, Eckersley R. Contrast-enhanced ultrasound: Basic physics and technology overview. In: Lencioni R, editor. Enhancing the Role of Ultrasound with Contrast

[3] Kono Y, Mattrey RF. Ultrasound of the liver. Radiologic Clinics of North America. 2005;

[4] Nilsson A. Contrast-enhanced ultrasound of the kidneys. European Radiology. 2004;

University of Medicine and Pharmacy "Iuliu Hatieganu", Cluj-Napoca, Romania

\*Address all correspondence to: ciobanulidia@yahoo.com

Agents. Milan: Springer; 2006. pp. 3-14

**16. Conclusions**

**Acknowledgement**

**Author details**

**References**

2012;**14**(4):307-317

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In the third category, called IIF, the cysts have multiple septa, minimally thickened walls, thin or thick calcifications. On CEUS, a discrete enhancement of the walls and septa is depicted. The malignant potential is 5%, and these lesions need regular monitoring for 6 months [8, 25].

Renal cysts from the fourth category, called III, present homogeneous of irregular thickening of the walls and/or septa and irregular calcifications. The CEUS examination reveals multiple contrast enhancing septa. The malignant potential is 50% [8, 25].

In the last category, called IV, the cysts present solid components together with homogeneous of irregular thickening of the walls and/or septa and irregular calcifications. The CEUS examination depicts multiple contrast enhancing septa and irregular contrast enhancing soft tissue components. These lesions are considered malignant [8, 25].

The accuracy of CEUS in differentiating renal cystic lesions as benign or malignant is similar to CE-CT [11]. The sensitivity of CEUS for depicting the vascular signal at the level of the cystic components (septa, walls, and nodules) is superior to CE-CT [26]. However, CEUS does not have the same sensitivity as CT in detecting calcifications, a confounding factor for the measurement of wall thickness and septum [27].
