Initial experience of percutaneous renal cryosurgery under the guidance of a horizontal open MRI system.
OBJECTIVE
The aim of this study was to obtain preliminary results of cryoablation of renal tumors by using a percutaneous approach guided by a horizontal open MRI system, and to assess the safety and efficacy of this procedure.


METHODS
Four patients with renal tumors underwent percutaneous cryosurgery with local anesthesia using a horizontal open MRI system (AIRIS II, Hitachi Medical Corp., Tokyo, Japan). The size of the mass was radiographically documented as 4 cm or less in diameter. A 2- or 3-mm cryoprobe was advanced into the renal mass under real-time MR monitoring. Growth of the iceball during cryoablation was monitored by two-dimensional MR images. Follow-up dynamic CT and physical examination were done after two weeks and six weeks.


RESULTS
MR imaging demonstrated the iceballs as sharply marginated regions of signal loss that expanded and engulfed the renal mass with clear contrast between the iceball and surrounding tissue. Cryoablated tumors resolved, and there were no serious complications and no clinically significant changes during the procedures and follow-up study.


CONCLUSIONS
In this limited clinical trial of percutaneous renal tumor surgery, cryoablation demonstrated its feasibility with minimal morbidity. Intraprocedual MR-guided cryosurgery can be used as a safe modality, although further studies are necessary to determine the long-term efficacy of this procedure.
Harada
J
J
Department of Radiology, Jikei University School of Medicine, Kashiwa Hospital, Chiba, Japan.
Dohi
M
M
Mogami
T
T
Fukuda
K
K
Miki
K
K
Furuta
N
N
Kishimoto
K
K
Simizu
T
T
Miyasaka
K
K
D000368:Aged; D001706:Biopsy; D002292:Carcinoma, Renal Cell / Q000473:pathology / Q000601:surgery*; D003404:Creatinine / Q000097:blood; D003452:Cryosurgery; D005260:Female; D005471:Fluoroscopy; D005500:Follow-Up Studies; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology / Q000601:surgery*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
D003404:Creatinine