Percutaneous ablation in the kidney

Abstract

Percutaneous ablation in the kidney is now performed as a standard therapeutic nephron-sparing option in patients who are poor candidates for resection. Its increasing use has been largely prompted by the rising incidental detection of renal cell carcinomas with cross-sectional imaging and the need to preserve renal function in patients with comorbid conditions, multiple renal cell carcinomas, and/or heritable renal cancer syndromes. Clinical studies to date indicate that radiofrequency ablation and cryoablation are effective therapies with acceptable short- to intermediate-term outcomes and with a low risk in the appropriate setting, with attention to pre-, peri-, and postprocedural detail. The results following percutaneous radiofrequency ablation and cryoablation in the treatment of renal cell carcinoma are reviewed in this article, including those of several larger scale studies of ablation of T1a tumors. Clinical and technical considerations unique to ablation in the kidney are presented, and potential complications are discussed.

Figure 1a:

Early treatment of RCC with percutaneous RF ablation. (a) Axial contrast-enhanced CT scan of left kidney shows 2-cm RCC arising from posterior midportion of the left kidney. (b) Axial contrast-enhanced CT scan 5 years after technically successful percutaneous RF ablation shows no evidence for enhancement in the ablation zone. Local control was sustained on follow-up.

Figure 1b:

Early treatment of RCC with percutaneous RF ablation. (a) Axial contrast-enhanced CT scan of left kidney shows 2-cm RCC arising from posterior midportion of the left kidney. (b) Axial contrast-enhanced CT scan 5 years after technically successful percutaneous RF ablation shows no evidence for enhancement in the ablation zone. Local control was sustained on follow-up.

Figure 2a:

Cryoablation of RCC. (a) Axial contrast-enhanced CT scan in 78-year-old woman shows 1.4-cm enhancing left RCC (arrow). (b) Intraprocedural nonenhanced CT scan obtained in prone position at time of cryoablation shows cryoprobe within left renal mass (arrow). (c) Nonenhanced and (d) contrast-enhanced CT scans 3 months after ablation show nonenhancing ablation zone (arrow).

Figure 2b:

Cryoablation of RCC. (a) Axial contrast-enhanced CT scan in 78-year-old woman shows 1.4-cm enhancing left RCC (arrow). (b) Intraprocedural nonenhanced CT scan obtained in prone position at time of cryoablation shows cryoprobe within left renal mass (arrow). (c) Nonenhanced and (d) contrast-enhanced CT scans 3 months after ablation show nonenhancing ablation zone (arrow).

Figure 2c:

Cryoablation of RCC. (a) Axial contrast-enhanced CT scan in 78-year-old woman shows 1.4-cm enhancing left RCC (arrow). (b) Intraprocedural nonenhanced CT scan obtained in prone position at time of cryoablation shows cryoprobe within left renal mass (arrow). (c) Nonenhanced and (d) contrast-enhanced CT scans 3 months after ablation show nonenhancing ablation zone (arrow).

Figure 2d:

Cryoablation of RCC. (a) Axial contrast-enhanced CT scan in 78-year-old woman shows 1.4-cm enhancing left RCC (arrow). (b) Intraprocedural nonenhanced CT scan obtained in prone position at time of cryoablation shows cryoprobe within left renal mass (arrow). (c) Nonenhanced and (d) contrast-enhanced CT scans 3 months after ablation show nonenhancing ablation zone (arrow).

Figure 3a:

Incidental perinephric bleeding during percutaneous renal RF ablation. (a) Axial contrast-enhanced CT scan shows 1.5-cm RCC in lower pole of right kidney. (b) Intraprocedural axial contrast-enhanced CT scan shows electrode within mass in lower pole of right kidney, with adjacent small (<2 cm) perinephric hemorrhage (arrow). This finding is frequently seen and typically is self-limited; it resolved at follow-up imaging.

Figure 3b:

Incidental perinephric bleeding during percutaneous renal RF ablation. (a) Axial contrast-enhanced CT scan shows 1.5-cm RCC in lower pole of right kidney. (b) Intraprocedural axial contrast-enhanced CT scan shows electrode within mass in lower pole of right kidney, with adjacent small (<2 cm) perinephric hemorrhage (arrow). This finding is frequently seen and typically is self-limited; it resolved at follow-up imaging.

Figure 4a:

Protective maneuvers used during percutaneous ablation of RCC. (a) Intraprocedural axial contrast-enhanced CT scan of 1.5-cm RCC in lower pole of right kidney, with instillation of CO₂ (arrow) to displace renal mass from adjacent right colon. (b) Intraprocedural axial nonenhanced CT scan of 3.5-cm left RCC, with right lateral decubitus positioning and use of hydrodissection (arrow) to separate kidney from right lateral chest wall and intercostal nerve.

Figure 4b:

Protective maneuvers used during percutaneous ablation of RCC. (a) Intraprocedural axial contrast-enhanced CT scan of 1.5-cm RCC in lower pole of right kidney, with instillation of CO₂ (arrow) to displace renal mass from adjacent right colon. (b) Intraprocedural axial nonenhanced CT scan of 3.5-cm left RCC, with right lateral decubitus positioning and use of hydrodissection (arrow) to separate kidney from right lateral chest wall and intercostal nerve.

Figure 5a:

Expected evolution of imaging findings prior to and following percutaneous RF ablation. (a) Axial contrast-enhanced CT scan shows 1.5-cm enhancing RCC abutting left renal collecting system. (b) Axial intraprocedural nonenhanced CTscan shows electrode (arrow) within the tumor. (c) Axial contrast-enhanced CT scan 2 months after ablation shows trace left perinephric fat stranding and nonenhancement in the ablation zone. Nodularity within left perinephric fat (arrows), when observed along the electrode track, may mimic tumor seeding. (d) Axial contrast-enhanced CT scan 6 months after percutaneous RF ablation shows decreased size of ablation zone and decreased left perinephric fat stranding. Axial contrast-enhanced CT scans (e) 12 and (f) 18 months after ablation show continued decrease in size of ablation zone and continued decrease in left perinephric fat stranding and nodularity.

Figure 5b:

Expected evolution of imaging findings prior to and following percutaneous RF ablation. (a) Axial contrast-enhanced CT scan shows 1.5-cm enhancing RCC abutting left renal collecting system. (b) Axial intraprocedural nonenhanced CTscan shows electrode (arrow) within the tumor. (c) Axial contrast-enhanced CT scan 2 months after ablation shows trace left perinephric fat stranding and nonenhancement in the ablation zone. Nodularity within left perinephric fat (arrows), when observed along the electrode track, may mimic tumor seeding. (d) Axial contrast-enhanced CT scan 6 months after percutaneous RF ablation shows decreased size of ablation zone and decreased left perinephric fat stranding. Axial contrast-enhanced CT scans (e) 12 and (f) 18 months after ablation show continued decrease in size of ablation zone and continued decrease in left perinephric fat stranding and nodularity.

Figure 5c:

Expected evolution of imaging findings prior to and following percutaneous RF ablation. (a) Axial contrast-enhanced CT scan shows 1.5-cm enhancing RCC abutting left renal collecting system. (b) Axial intraprocedural nonenhanced CTscan shows electrode (arrow) within the tumor. (c) Axial contrast-enhanced CT scan 2 months after ablation shows trace left perinephric fat stranding and nonenhancement in the ablation zone. Nodularity within left perinephric fat (arrows), when observed along the electrode track, may mimic tumor seeding. (d) Axial contrast-enhanced CT scan 6 months after percutaneous RF ablation shows decreased size of ablation zone and decreased left perinephric fat stranding. Axial contrast-enhanced CT scans (e) 12 and (f) 18 months after ablation show continued decrease in size of ablation zone and continued decrease in left perinephric fat stranding and nodularity.

Figure 5d:

Expected evolution of imaging findings prior to and following percutaneous RF ablation. (a) Axial contrast-enhanced CT scan shows 1.5-cm enhancing RCC abutting left renal collecting system. (b) Axial intraprocedural nonenhanced CTscan shows electrode (arrow) within the tumor. (c) Axial contrast-enhanced CT scan 2 months after ablation shows trace left perinephric fat stranding and nonenhancement in the ablation zone. Nodularity within left perinephric fat (arrows), when observed along the electrode track, may mimic tumor seeding. (d) Axial contrast-enhanced CT scan 6 months after percutaneous RF ablation shows decreased size of ablation zone and decreased left perinephric fat stranding. Axial contrast-enhanced CT scans (e) 12 and (f) 18 months after ablation show continued decrease in size of ablation zone and continued decrease in left perinephric fat stranding and nodularity.

Figure 5e:

Expected evolution of imaging findings prior to and following percutaneous RF ablation. (a) Axial contrast-enhanced CT scan shows 1.5-cm enhancing RCC abutting left renal collecting system. (b) Axial intraprocedural nonenhanced CTscan shows electrode (arrow) within the tumor. (c) Axial contrast-enhanced CT scan 2 months after ablation shows trace left perinephric fat stranding and nonenhancement in the ablation zone. Nodularity within left perinephric fat (arrows), when observed along the electrode track, may mimic tumor seeding. (d) Axial contrast-enhanced CT scan 6 months after percutaneous RF ablation shows decreased size of ablation zone and decreased left perinephric fat stranding. Axial contrast-enhanced CT scans (e) 12 and (f) 18 months after ablation show continued decrease in size of ablation zone and continued decrease in left perinephric fat stranding and nodularity.

Figure 5f:

Expected evolution of imaging findings prior to and following percutaneous RF ablation. (a) Axial contrast-enhanced CT scan shows 1.5-cm enhancing RCC abutting left renal collecting system. (b) Axial intraprocedural nonenhanced CTscan shows electrode (arrow) within the tumor. (c) Axial contrast-enhanced CT scan 2 months after ablation shows trace left perinephric fat stranding and nonenhancement in the ablation zone. Nodularity within left perinephric fat (arrows), when observed along the electrode track, may mimic tumor seeding. (d) Axial contrast-enhanced CT scan 6 months after percutaneous RF ablation shows decreased size of ablation zone and decreased left perinephric fat stranding. Axial contrast-enhanced CT scans (e) 12 and (f) 18 months after ablation show continued decrease in size of ablation zone and continued decrease in left perinephric fat stranding and nodularity.

Figure 6a:

Use of percutaneous RF ablation to treat metastatic RCC. (a) Axial contrast-enhanced CT scan shows heterogeneous enhancing 3.50-cm intrasplenic mass (arrow). Biopsy confirmed metastatic RCC. (b) Axial contrast-enhanced CT scan 6 months after percutaneous RF ablation shows decreased nonenhancing ablation zone (arrow) and no evidence of residual tumor. (Reprinted, with permission, from reference .)

Figure 6b:

Use of percutaneous RF ablation to treat metastatic RCC. (a) Axial contrast-enhanced CT scan shows heterogeneous enhancing 3.50-cm intrasplenic mass (arrow). Biopsy confirmed metastatic RCC. (b) Axial contrast-enhanced CT scan 6 months after percutaneous RF ablation shows decreased nonenhancing ablation zone (arrow) and no evidence of residual tumor. (Reprinted, with permission, from reference .)