Perfusion-CT monitoring of cryo-ablated renal cells tumors.
BACKGROUND
No single and thoroughly validated imaging method in monitoring of cryoablated renal cell carcinoma (RCC) is available. The purpose of our study was to determine the feasibility of dynamic contrast-enhanced perfusion CT (pCT) in evaluating the hemodynamic response of RCC.


METHODS
15 patients (14 male, 1 female; age range, 43-81 years; mean age, 62 years) with cryoablated RCC via a transperitoneal approach, underwent to pCT 6-8 months after cryo-therapy. pCT was performed for 65 seconds after intravenous injection of contrast medium (80 mL, 370 mg iodine per millilitre, 4 mL/sec). Perfusion parameters (Time/Density curve; Blood flow, BF; Blood Volume, BV; Mean Transit Time, MTT; Permeability-Surface Area Product, PS) were sampled in the cryoablated tumor area and in ipsilateral renal cortex using deconvolution-based method. A tumor was considered to be not responsive to treatment by CT evidence of pathological contrast enhancement in the cryoablated area or renal mass persistence compared with the preoperative CT control. Written informed consent was obtained from all participants before the study.


RESULTS
After cryotherapy, successfully ablated tumor (n = 13) showed decrease in BV (5,39 +/- 1,28 mL/100 g), BF (69,92 +/- 20,12 mL/100 g/min) and PS (16,66 +/- 5,67 mL/100 g/min) value and increased value of MTT (25,35 +/- 4,3 sec) compared with those of normal renal cortex (BV: 117,86 +/- 31,87 mL/100 g/min; BF: 392,39 +/- 117,32 mL/100 g/min; MTT: 18,02 +/- 3,6 sec; PS: 81,68 +/- 22,75 mL/100 g/min). In one patient, assessment of perfusion parameters was not feasible for breathing artifacts. One tumor showed poor response to treatment by the evidence of nodular contrast enhancement in the region encompassing the original lesion. Two typical enhancement patterns were obtained comparing the Time-Density curves of responsive and not responsive ablated tumors.


CONCLUSIONS
Perfusion CT seems to be a feasible and promising technique in monitoring the effects of cryoablation therapy.
Squillaci
Ettore
E
Department of Diagnostic and Molecular Imaging, Interventional Radiology and Radiotherapy - University Tor Vergata, Rome, Italy. ettoresquillaci@tiscali.it
Manenti
Guglielmo
G
Cicciò
Carmelo
C
Nucera
Francesca
F
Bove
Pierluigi
P
Vespasiani
Giuseppe
G
Russolillo
Laura
L
Simonetti
Giovanni
G
D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging* / Q000628:therapy; D017679:Cryotherapy; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual / Q000000981:diagnostic imaging*; D055420:Perfusion Imaging; D014057:Tomography, X-Ray Computed