This requires a correction method, as proposed by Nabavi et al , in assessing PS parameter according to the Renkin-Crone equation, E = 1 – exp (-PS/BF), to avoid inaccurate determination of blood flow when compartment model is used. According to a previous study , tumor was considered successfully ablated by no evidence of enhanced focal masses within the treated lesion that frequently decreases in size. Perfusion parameters were obtained in tumor cryoablated area and in normal ipsilateral renal cortex to verify selleck the changes in perfusion parameters due to cryo-therapy.
No post-procedural biopsy was performed on any tumor. Hence a small number of patients were enclosed in our preliminary study, no statistical analysis was performed. Results Good image quality was obtained in 14 of 15 patients. 1 Patient had technically inadequate pCT examination due to motion artifacts with data not included in the analysis. 1 patient showed residual tumour. The perfusion parameters (TA, TTP, wash-in rate, Peak contrast enhancement and BV, BF, PS and MTT) in the cryoablated area and normal renal parenchyma of 14 patients were calculated and comparatively evaluated (Table 1, 2). Two pattern curves with different morphology were generated analyzing Time/Density plots. A particular pattern (Type 1), characterised by rapid density increase click here and tendency
to decrease after density peak, was observed in the patient (n = 1) with evidence of residual tumor (Figure 1). A second characteristic curve
(Type 2), with steady density increase or a plateau following an initial rise, was identified in patients (n = 13) responsive to treatment, with no evidence of residual tumor (Figure Beta adrenergic receptor kinase 2). Figure 1 Cryoablated Renal Cell Carcinoma (RCC) in the right kidney of a 47 years-old patient. a) Perfusional CT scan shows three regions of interest, selected on abdominal aorta (ROI 1), normal ipsilateral renal cortex (ROI 2), cryoablated tumor area (ROI 3). b) The corresponding time-density curves show contrast enhancement kinetic with typical pattern at responsive cryoablated tumor area (curve 3: slower initial enhancement, decreased amplitude, slower wash-out) compared to abdominal aorta (curve 1) and ipsilateral normal renal cortex (curve 2). Blood colour maps (c, Blood Volume, BV; d, Blood Flow, BF; e, Permeability – Surface Area Product, PS) at the same levels, show the high arterial (ROI 1) and parenchymal (ROI 2) perfusion parameters with no colour encoding in successfully cryoablated area (ROI 3). Figure 2 Residual renal cancer cell (RCC) in right kidney, six months after cryoablation. Pre-treatment contrast-enhanced cortico-medullary phase CT scan (a) shows exophytic solid tumor with heterogeneous contrast-enhancement. Post-treatment perfusional CT (b) shows a nodular enhancing component (ROI 3) in the medial portion of the ablation zone with peripheral linear enhancement in the peri-renal fat, suggestive for residual tumour.